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Sample records for 2-component beam consisting

  1. Consistency check of photon beam physical data after recommissioning process

    NASA Astrophysics Data System (ADS)

    Kadman, B.; Chawapun, N.; Ua-apisitwong, S.; Asakit, T.; Chumpu, N.; Rueansri, J.

    2016-03-01

    In radiotherapy, medical linear accelerator (Linac) is the key system used for radiation treatments delivery. Although, recommissioning was recommended after major modification of the machine by AAPM TG53, but it might not be practical in radiotherapy center with heavy workloads. The main purpose of this study was to compare photon beam physical data between initial commissioning and recommissioning of 6 MV Elekta Precise linac. The parameters for comparing were the percentage depth dose (PDD) and beam profiles. The clinical commissioning test cases followed IAEA-TECDOC-1583 were planned on REF 91230 IMRT Dose Verification Phantom by Philips’ Pinnacle treatment planning system. The Delta4PT was used for dose distribution verification with 90% passing criteria of the gamma index (3%/3mm). Our results revealed that the PDDs and beam profiles agreed within a tolerance limit recommended by TRS430. Most of the point doses and dose distribution verification passed the acceptance criteria. This study showed the consistency of photon beam physical data after recommissioning process. There was a good agreement between initial commissioning and recommissioning within a tolerance limit, demonstrated that the full recommissioning process might not be required. However, in the complex treatment planning geometry, the initial data should be applied with great caution.

  2. Simultaneous determination of electron beam profile and material response using self-consistent iterative method

    NASA Astrophysics Data System (ADS)

    Kandel, Yudhishthir; Denbeaux, Gregory

    2016-08-01

    We develop a novel iterative method to accurately measure electron beam shape (current density distribution) and monotonic material response as a function of position. A common method is to scan an electron beam across a knife edge along many angles to give an approximate measure of the beam profile, however such scans are not easy to obtain in all systems. The present work uses only an electron beam and multiple exposed regions of a thin film of photoresist to measure the complete beam profile for any beam shape, where the material response is characterized externally. This simplifies the setup of new experimental tools. We solve for self-consistent photoresist thickness loss response to dose and the electron beam profile simultaneously by optimizing a novel functional iteratively. We also show the successful implementation of the method in a real world data set corrupted by noise and other experimental variabilities.

  3. On the use of consistent approximations for the optimal design of beams

    SciTech Connect

    Polak, E.; Neto, C.K.

    1994-12-31

    Most optimal design problems can only be solved through discretization. One solution strategy is to expand the original problem into an infinite sequence of finite dimensional, approximating nonlinear programming problems, which can be solved using standard algorithms. In this paper, an expansion strategy based on the concept of consistent approximations is proposed for certain optimal beam design problems, where the beam is modelled using Euler-Bernoulli beam theory. It is shown that any accumulation point of the sequence of the stationary points of the family of approximating problems is a stationary point of the original, infinite-dimensional problem. Numerical results are presented for problems of optimal design of fixed beams.

  4. Full data consistency conditions for cone-beam projections with sources on a plane.

    PubMed

    Clackdoyle, Rolf; Desbat, Laurent

    2013-12-07

    Cone-beam consistency conditions (also known as range conditions) are mathematical relationships between different cone-beam projections, and they therefore describe the redundancy or overlap of information between projections. These redundancies have often been exploited for applications in image reconstruction. In this work we describe new consistency conditions for cone-beam projections whose source positions lie on a plane. A further restriction is that the target object must not intersect this plane. The conditions require that moments of the cone-beam projections be polynomial functions of the source positions, with some additional constraints on the coefficients of the polynomials. A precise description of the consistency conditions is that the four parameters of the cone-beam projections (two for the detector, two for the source position) can be expressed with just three variables, using a certain formulation involving homogeneous polynomials. The main contribution of this work is our demonstration that these conditions are not only necessary, but also sufficient. Thus the consistency conditions completely characterize all redundancies, so no other independent conditions are possible and in this sense the conditions are full. The idea of the proof is to use the known consistency conditions for 3D parallel projections, and to then apply a 1996 theorem of Edholm and Danielsson that links parallel to cone-beam projections. The consistency conditions are illustrated with a simulation example.

  5. MultiSIMNRA: A computational tool for self-consistent ion beam analysis using SIMNRA

    NASA Astrophysics Data System (ADS)

    Silva, T. F.; Rodrigues, C. L.; Mayer, M.; Moro, M. V.; Trindade, G. F.; Aguirre, F. R.; Added, N.; Rizzutto, M. A.; Tabacniks, M. H.

    2016-03-01

    SIMNRA is widely adopted by the scientific community of ion beam analysis for the simulation and interpretation of nuclear scattering techniques for material characterization. Taking advantage of its recognized reliability and quality of the simulations, we developed a computer program that uses multiple parallel sessions of SIMNRA to perform self-consistent analysis of data obtained by different ion beam techniques or in different experimental conditions of a given sample. In this paper, we present a result using MultiSIMNRA for a self-consistent multi-elemental analysis of a thin film produced by magnetron sputtering. The results demonstrate the potentialities of the self-consistent analysis and its feasibility using MultiSIMNRA.

  6. Appropriate Measures and Consistent Standard for High Energy Laser Beam Quality (Postprint)

    DTIC Science & Technology

    2006-08-01

    may be distributed to individuals. “Appropriate measures and consistent standard for high energy laser beam quality” Dr. T. Sean Ross (AFRL/DELO... High Power Solid State Laser Branch b Air Force Research Laboratory, Directed Energy Directorate, Laser Division, Tactical Systems Branch Ross...e2 must be used. If the power or energy measured in the small area around the focal spot is Ps and the total laser output power or energy is P, the

  7. Characterisation of gunshot residue particles using self-consistent ion beam analysis

    NASA Astrophysics Data System (ADS)

    Bailey, M. J.; Jeynes, C.

    2009-06-01

    Individual particles of gunshot residue were studied with particle-induced X-ray emission and backscattering spectrometry using a 2.5 MeV H + beam focussed to ˜4 μm and self-consistent fitting of the data. The geometry of these spherical particles was considered in order to accurately fit the corresponding particle spectrum and therefore to quantify the trace element composition of these particles. The demonstrable self-consistency of this method allows the compositions of most residue particles to be determined unambiguously and with a higher sensitivity to trace elements than conventional methods.

  8. Study on the consistency of the voxel of two photon polymerization with inclined beam

    NASA Astrophysics Data System (ADS)

    Cheng, Kai; Zhou, Xiaoqin; Zheng, Xu; Lin, Jieqiong

    2016-12-01

    In the process of two photon polymerization, the focused beam should be perpendicular to the materials to be processed. But actually it is hard to control, because of the errors of the optical system and the three-dimensional motion platform. So, the inconsistencies of voxels in size and angle due to the errors mentioned above will seriously impact the surface quality of the products. In this paper, the size, angle and location of the titled voxels formed by inclined beam are simulated according to matrix optics and polymerization theory. According to the simulation results, a method for angle errors compensation with the aid of scanning galvanometer is proposed. Although the angle of the voxels can be controlled by scanning galvanometer, but the deflection angles of the scanning galvanometer have a certain range, it should be lower than 3°, or the deformation of the voxels will be serious. Therefore the consistency of the voxel in both size and angle will be ensured.

  9. Data consistency-driven scatter kernel optimization for x-ray cone-beam CT

    NASA Astrophysics Data System (ADS)

    Kim, Changhwan; Park, Miran; Sung, Younghun; Lee, Jaehak; Choi, Jiyoung; Cho, Seungryong

    2015-08-01

    Accurate and efficient scatter correction is essential for acquisition of high-quality x-ray cone-beam CT (CBCT) images for various applications. This study was conducted to demonstrate the feasibility of using the data consistency condition (DCC) as a criterion for scatter kernel optimization in scatter deconvolution methods in CBCT. As in CBCT, data consistency in the mid-plane is primarily challenged by scatter, we utilized data consistency to confirm the degree of scatter correction and to steer the update in iterative kernel optimization. By means of the parallel-beam DCC via fan-parallel rebinning, we iteratively optimized the scatter kernel parameters, using a particle swarm optimization algorithm for its computational efficiency and excellent convergence. The proposed method was validated by a simulation study using the XCAT numerical phantom and also by experimental studies using the ACS head phantom and the pelvic part of the Rando phantom. The results showed that the proposed method can effectively improve the accuracy of deconvolution-based scatter correction. Quantitative assessments of image quality parameters such as contrast and structure similarity (SSIM) revealed that the optimally selected scatter kernel improves the contrast of scatter-free images by up to 99.5%, 94.4%, and 84.4%, and of the SSIM in an XCAT study, an ACS head phantom study, and a pelvis phantom study by up to 96.7%, 90.5%, and 87.8%, respectively. The proposed method can achieve accurate and efficient scatter correction from a single cone-beam scan without need of any auxiliary hardware or additional experimentation.

  10. Self-Consistent Simulations of Heavy-Ion Beams Interacting with Electron-Clouds

    SciTech Connect

    Vay, J; Furman, M A; Seidl, P A; Cohen, R H; Friedman, A; Grote, D P; Covo, M K; Molvik, A W; Stoltz, P H; Veitzer, S; Verboncoeur, J P

    2006-08-04

    Electron-clouds and rising desorbed gas pressure limit the performance of many existing accelerators and, potentially, that of future accelerators including heavy-ion warm-dense matter and fusion drivers. For the latter, self-consistent simulation of the interaction of the heavy-ion beam(s) with the electron-cloud is necessary. To this end, we have merged the two codes WARP (HIF accelerator code) and POSINST (high-energy e-cloud build-up code), and added modules for neutral gas molecule generation, gas ionization, and electron tracking algorithms in magnetic fields with large time steps. The new tool is being benchmarked against the High-Current Experiment (HCX) and good agreement has been achieved. The simulations have also aided diagnostic interpretation and have identified unanticipated physical processes. We present the ''roadmap'' describing the different modules and their interconnections, along with detailed comparisons with HCX experimental results, as well as a preliminary application to the modeling of electron clouds in the Large Hadron Collider.

  11. SELF-CONSISTENT LANGEVIN SIMULATION OF COULOMB COLLISIONS IN CHARGED-PARTICLE BEAMS

    SciTech Connect

    J. QIANG; R. RYNE; S. HABIB

    2000-05-01

    In many plasma physics and charged-particle beam dynamics problems, Coulomb collisions are modeled by a Fokker-Planck equation. In order to incorporate these collisions, we present a three-dimensional parallel Langevin simulation method using a Particle-In-Cell (PIC) approach implemented on high-performance parallel computers. We perform, for the first time, a fully self-consistent simulation, in which the friction and diffusion coefficients are computed from first principles. We employ a two-dimensional domain decomposition approach within a message passing programming paradigm along with dynamic load balancing. Object oriented programming is used to encapsulate details of the communication syntax as well as to enhance reusability and extensibility. Performance tests on the SGI Origin 2000 and the Cray T3E-900 have demonstrated good scalability. Work is in progress to apply our technique to intrabeam scattering in accelerators.

  12. Photon-number statistics of twin beams: Self-consistent measurement, reconstruction, and properties

    SciTech Connect

    Peřina, Jan Jr.; Haderka, Ondřej; Michálek, Václav

    2014-12-04

    A method for the determination of photon-number statistics of twin beams using the joint signal-idler photocount statistics obtained by an iCCD camera is described. It also provides absolute quantum detection efficiency of the camera. Using the measured photocount statistics, quasi-distributions of integrated intensities are obtained. They attain negative values occurring in characteristic strips an a consequence of pairing of photons in twin beams.

  13. Energy regeneration model of self-consistent field of electron beams into electric power*

    NASA Astrophysics Data System (ADS)

    Kazmin, B. N.; Ryzhov, D. R.; Trifanov, I. V.; Snezhko, A. A.; Savelyeva, M. V.

    2016-04-01

    We consider physic-mathematical models of electric processes in electron beams, conversion of beam parameters into electric power values and their transformation into users’ electric power grid (onboard spacecraft network). We perform computer simulation validating high energy efficiency of the studied processes to be applied in the electric power technology to produce the power as well as electric power plants and propulsion installation in the spacecraft.

  14. Initial Self-Consistent 3D Electron-Cloud Simulations of the LHC Beam with the Code WARP+POSINST

    SciTech Connect

    Vay, J; Furman, M A; Cohen, R H; Friedman, A; Grote, D P

    2005-10-11

    We present initial results for the self-consistent beam-cloud dynamics simulations for a sample LHC beam, using a newly developed set of modeling capability based on a merge [1] of the three-dimensional parallel Particle-In-Cell (PIC) accelerator code WARP [2] and the electron-cloud code POSINST [3]. Although the storage ring model we use as a test bed to contain the beam is much simpler and shorter than the LHC, its lattice elements are realistically modeled, as is the beam and the electron cloud dynamics. The simulated mechanisms for generation and absorption of the electrons at the walls are based on previously validated models available in POSINST [3, 4].

  15. Self-consistent drift-diffusion-reaction model for the electron beam interaction with dielectric samples

    SciTech Connect

    Raftari, B. Budko, N. V. Vuik, C.

    2015-11-28

    The charging of insulating samples degrades the quality and complicates the interpretation of images in scanning electron microscopy and is important in other applications, such as particle detectors. In this paper, we analyze this nontrivial phenomenon on different time scales employing the drift-diffusion-reaction approach augmented with the trapping rate equations and a realistic semi-empirical source function describing the pulsed nature of the electron beam. We consider both the fast processes following the impact of a single primary electron, the slower dynamics resulting from the continuous bombardment of a sample, and the eventual approach to the steady-state regime.

  16. Self-consistent analysis of radiation and relativistic electron beam dynamics in a helical wiggler using Lienard-Wiechert fields

    SciTech Connect

    Tecimer, M.; Elias, L.R.

    1995-12-31

    Lienard-Wiechert (LW) fields, which are exact solutions of the Wave Equation for a point charge in free space, are employed to formulate a self-consistent treatment of the electron beam dynamics and the evolution of the generated radiation in long undulators. In a relativistic electron beam the internal forces leading to the interaction of the electrons with each other can be computed by means of retarded LW fields. The resulting electron beam dynamics enables us to obtain three dimensional radiation fields starting from an initial incoherent spontaneous emission, without introducing a seed wave at start-up. Based on the formalism employed here, both the evolution of the multi-bucket electron phase space dynamics in the beam body as well as edges and the relative slippage of the radiation with respect to the electrons in the considered short bunch are naturally embedded into the simulation model. In this paper, we present electromagnetic radiation studies, including multi-bucket electron phase dynamics and angular distribution of radiation in the time and frequency domain produced by a relativistic short electron beam bunch interacting with a circularly polarized magnetic undulator.

  17. Self-Consistent 3D Modeling of Electron Cloud Dynamics and Beam Response

    SciTech Connect

    Furman, Miguel; Furman, M.A.; Celata, C.M.; Kireeff-Covo, M.; Sonnad, K.G.; Vay, J.-L.; Venturini, M.; Cohen, R.; Friedman, A.; Grote, D.; Molvik, A.; Stoltz, P.

    2007-04-02

    We present recent advances in the modeling of beam electron-cloud dynamics, including surface effects such as secondary electron emission, gas desorption, etc, and volumetric effects such as ionization of residual gas and charge-exchange reactions. Simulations for the HCX facility with the code WARP/POSINST will be described and their validity demonstrated by benchmarks against measurements. The code models a wide range of physical processes and uses a number of novel techniques, including a large-timestep electron mover that smoothly interpolates between direct orbit calculation and guiding-center drift equations, and a new computational technique, based on a Lorentz transformation to a moving frame, that allows the cost of a fully 3D simulation to be reduced to that of a quasi-static approximation.

  18. Toward fully self-consistent simulation of the interaction of E-Clouds and beams with WARP-POSINST

    SciTech Connect

    LLNL; Furman, M.A.; Furman, M.A.; Celata, C.M.; Sonnad, K.; Venturini, M.; Cohen, R.H.; Friedman, A.; Grote, D.P.; Vay, J.-L.

    2012-04-09

    To predict the evolution of electron clouds and their effect on the beam, the high energy physics community has relied so far on the complementary use of 'buildup' and 'single/multi-bunch instability' reduced descriptions. The former describes the evolution of electron clouds at a given location in the ring, or 'station', under the influence of prescribed beams and external fields [1], while the latter (sometimes also referred as the 'quasi-static' approximation [2]) follows the interaction between the beams and the electron clouds around the accelerator with prescribed initial distributions of electrons, assumed to be concentrated at a number of discrete 'stations' around the ring. Examples of single bunch instability codes include HEADTAIL [3], QuickPIC [4, 5], and PEHTS [6]. By contrast, a fully self-consistent approach, in which both the electron cloud and beam distributions evolve simultaneously under their mutual influence without any restriction on their relative motion, is required for modeling the interaction of high-intensity beams with electron clouds for heavy-ion beam-driven fusion and warm-dense matter science. This community has relied on the use of Particle-In-Cell (PIC) methods through the development and use of the WARP-POSINST code suite [1, 7, 8]. The development of novel numerical techniques (including adaptive mesh refinement, and a new 'drift-Lorentz' particle mover for tracking charged particles in magnetic fields using large time steps) has enabled the first application of WARP-POSINST to the fully self-consistent modeling of beams and electron clouds in high energy accelerators [9], albeit for only a few betatron oscillations. It was recently observed [10] that there exists a preferred frame of reference which minimizes the number of computer operations needed to simulate the interaction of relativistic objects. This opens the possibility of reducing the cost of fully self-consistent simulations for the interaction of ultrarelativistic

  19. A fully consistent linearized model for vibration analysis of rotating beams in the framework of geometrically exact theory

    NASA Astrophysics Data System (ADS)

    Invernizzi, Davide; Dozio, Lorenzo

    2016-05-01

    The equations of motions governing the free vibrations of prismatic slender beams rotating in a plane at constant angular velocity are derived according to a geometrically exact approach. Compared to other modeling methods, additional stiffening terms induced by pre-stress are found in the dynamic equations after fully consistent linearization about the deformed equilibrium configuration. These terms include axial, bending and torsional stiffening effects which arise when second-order generalized strains are retained. It is shown that their contribution becomes relevant at moderate to high angular speeds, where high means that the equilibrium state is subject to strains close to the limit where a physically linear constitutive law still applies. In particular, the importance of the axial stiffening is specifically investigated. The natural frequencies as a function of the angular velocity and other system parameters are computed and compared with benchmark cases available in the literature. Finally, the error on the modal characteristics of the rotating beam is evaluated when the linearization is carried out about the undeformed configuration.

  20. Ion beam nanopatterning of III-V semiconductors: consistency of experimental and simulation trends within a chemistry-driven theory

    PubMed Central

    El-Atwani, O.; Norris, S. A.; Ludwig, K.; Gonderman, S.; Allain, J. P.

    2015-01-01

    Several proposed mechanisms and theoretical models exist concerning nanostructure evolution on III-V semiconductors (particularly GaSb) via ion beam irradiation. However, making quantitative contact between experiment on the one hand and model-parameter dependent predictions from different theories on the other is usually difficult. In this study, we take a different approach and provide an experimental investigation with a range of targets (GaSb, GaAs, GaP) and ion species (Ne, Ar, Kr, Xe) to determine new parametric trends regarding nanostructure evolution. Concurrently, atomistic simulations using binary collision approximation over the same ion/target combinations were performed to determine parametric trends on several quantities related to existing model. A comparison of experimental and numerical trends reveals that the two are broadly consistent under the assumption that instabilities are driven by chemical instability based on phase separation. Furthermore, the atomistic simulations and a survey of material thermodynamic properties suggest that a plausible microscopic mechanism for this process is an ion-enhanced mobility associated with energy deposition by collision cascades. PMID:26670948

  1. Ion beam nanopatterning of III-V semiconductors: Consistency of experimental and simulation trends within a chemistry-driven theory

    DOE PAGES

    El-Atwani, O.; Norris, S. A.; Ludwig, K.; ...

    2015-12-16

    In this study, several proposed mechanisms and theoretical models exist concerning nanostructure evolution on III-V semiconductors (particularly GaSb) via ion beam irradiation. However, making quantitative contact between experiment on the one hand and model-parameter dependent predictions from different theories on the other is usually difficult. In this study, we take a different approach and provide an experimental investigation with a range of targets (GaSb, GaAs, GaP) and ion species (Ne, Ar, Kr, Xe) to determine new parametric trends regarding nanostructure evolution. Concurrently, atomistic simulations using binary collision approximation over the same ion/target combinations were performed to determine parametric trends onmore » several quantities related to existing model. A comparison of experimental and numerical trends reveals that the two are broadly consistent under the assumption that instabilities are driven by chemical instability based on phase separation. Furthermore, the atomistic simulations and a survey of material thermodynamic properties suggest that a plausible microscopic mechanism for this process is an ion-enhanced mobility associated with energy deposition by collision cascades.« less

  2. Ion beam nanopatterning of III-V semiconductors: Consistency of experimental and simulation trends within a chemistry-driven theory

    SciTech Connect

    El-Atwani, O.; Norris, S. A.; Ludwig, K.; Gonderman, S.; Allain, J. P.

    2015-12-16

    In this study, several proposed mechanisms and theoretical models exist concerning nanostructure evolution on III-V semiconductors (particularly GaSb) via ion beam irradiation. However, making quantitative contact between experiment on the one hand and model-parameter dependent predictions from different theories on the other is usually difficult. In this study, we take a different approach and provide an experimental investigation with a range of targets (GaSb, GaAs, GaP) and ion species (Ne, Ar, Kr, Xe) to determine new parametric trends regarding nanostructure evolution. Concurrently, atomistic simulations using binary collision approximation over the same ion/target combinations were performed to determine parametric trends on several quantities related to existing model. A comparison of experimental and numerical trends reveals that the two are broadly consistent under the assumption that instabilities are driven by chemical instability based on phase separation. Furthermore, the atomistic simulations and a survey of material thermodynamic properties suggest that a plausible microscopic mechanism for this process is an ion-enhanced mobility associated with energy deposition by collision cascades.

  3. Ion beam nanopatterning of III-V semiconductors: consistency of experimental and simulation trends within a chemistry-driven theory

    NASA Astrophysics Data System (ADS)

    El-Atwani, O.; Norris, S. A.; Ludwig, K.; Gonderman, S.; Allain, J. P.

    2015-12-01

    Several proposed mechanisms and theoretical models exist concerning nanostructure evolution on III-V semiconductors (particularly GaSb) via ion beam irradiation. However, making quantitative contact between experiment on the one hand and model-parameter dependent predictions from different theories on the other is usually difficult. In this study, we take a different approach and provide an experimental investigation with a range of targets (GaSb, GaAs, GaP) and ion species (Ne, Ar, Kr, Xe) to determine new parametric trends regarding nanostructure evolution. Concurrently, atomistic simulations using binary collision approximation over the same ion/target combinations were performed to determine parametric trends on several quantities related to existing model. A comparison of experimental and numerical trends reveals that the two are broadly consistent under the assumption that instabilities are driven by chemical instability based on phase separation. Furthermore, the atomistic simulations and a survey of material thermodynamic properties suggest that a plausible microscopic mechanism for this process is an ion-enhanced mobility associated with energy deposition by collision cascades.

  4. Self-Consistent Simulation of Transport and Energy Deposition of Intense Laser-Accelerated Proton Beams in Solid-Density Matter.

    PubMed

    Kim, J; Qiao, B; McGuffey, C; Wei, M S; Grabowski, P E; Beg, F N

    2015-07-31

    The first self-consistent hybrid particle-in-cell (PIC) simulation of intense proton beam transport and energy deposition in solid-density matter is presented. Both the individual proton slowing-down and the collective beam-plasma interaction effects are taken into account with a new dynamic proton stopping power module that has been added to a hybrid PIC code. In this module, the target local stopping power can be updated at each time step based on its thermodynamic state. For intense proton beams, the reduction of target stopping power from the cold condition due to continuous proton heating eventually leads to broadening of the particle range and energy deposition far beyond the Bragg peak. For tightly focused beams, large magnetic field growth in collective interactions results in self-focusing of the beam and much stronger localized heating of the target.

  5. Quasi-stationary Regime of Tubular Electron Beam Confinement in a Self-consistent Penning-Malmberg trap

    SciTech Connect

    Lapshin, V. I.; Tarasov, I. K.; Tkachenko, I. V.; Tkachenko, V. I.

    2006-01-15

    Results of investigations of collective trap formation for a tubular electron beam which propagates in the conducting cylinder with a longitudinal magnetic field are submitted. It is shown that collective trap forms due to the double potential sag occurrence. Long lived particles accumulation may be theoretically described in the terms of shearless electron tubular beam rotation.

  6. Self-consistent simulation of an electron beam for a new autoresonant x-ray generator based on TE 102 rectangular mode

    NASA Astrophysics Data System (ADS)

    Dugar-Zhabon, V. D.; Orozco, E. A.; Herrera, A. M.

    2016-02-01

    The space cyclotron autoresonance interaction of an electron beam with microwaves of TE 102 rectangular mode is simulated. It is shown that in these conditions the beam electrons can achieve energies which are sufficient to generate hard x-rays. The physical model consists of a rectangular cavity fed by a magnetron oscillator through a waveguide with a ferrite isolator, an iris window and a system of dc current coils which generates an axially symmetric magnetic field. The 3D magnetic field profile is that which maintains the electron beam in the space autoresonance regime. To simulate the beam dynamics, a full self-consistent electromagnetic particle-in-cell code is developed. It is shown that the injected 12keV electron beam of 0.5A current is accelerated to energy of 225keV at a distance of an order of 17cm by 2.45GHz standing microwave field with amplitude of 14kV/cm.

  7. Self-consistent long-time simulation of chirping energetic particle modes and abrupt large events in beam-driven JT-60U tokamak plasmas

    NASA Astrophysics Data System (ADS)

    Bierwage, A.; Shinohara, K.; Todo, Y.; Aiba, N.; Ishikawa, M.; Matsunaga, G.; Takechi, M.; Yagi, M.

    2016-10-01

    Recurring bursts of chirping Alfvén modes as well as so-called Abrupt Large Events (ALE) that were observed in JT-60U tokamak plasmas driven by negative-ion-based neutral beams (N-NB) are reproduced in first-principle simulations performed with an extended version of the hybrid code MEGA. This code simulates the interactions between gyrokinetic fast ions and magnetohydrodynamic (MHD) modes in the presence of a realistic fast ion source and collisions, so that it self-consistently captures dynamics across a wide range of time scales (0.01-100 ms). Detailed comparisons with experimental measurements are performed. On the long time scale (10-100 ms) the simulation reproduces ALEs with the associated avalanche-like transport of fast ions. ALEs are shown to occur when multiple modes with toroidal mode numbers n = 1 , 2 , 3 are excited to large amplitudes. On the meso time scale (1-10 ms), bursts of chirping modes are reproduced, which are shown to be n = 1 energetic particle modes (EPM). On the short time scale (0.01-0.1 ms), pulsations and phase jumps are reproduced, which we interpret as the result of beating between multiple resonant wave packets. JSPS Grant-in-Aid for Scientific Research (No. 25820443, 16K18341). NIFS Collaborative Research Program (NIFS12KNTT016).

  8. Stimulated second-order processes in the interaction of a spinless quantum particle beam with a self-consistent electromagnetic field

    SciTech Connect

    Kuzelev, M. V.

    2011-02-15

    A nonlinear theory of interaction of two electromagnetic waves with a beam or a gas of spinless charged particles is developed. The effects of stimulated Compton scattering of electromagnetic waves and stimulated particle pair production (annihilation) during a collision of two electromagnetic quanta are investigated. Other stimulated processes that can occur only in a medium and decelerate electromagnetic waves are also considered. The relation between stimulated processes and various types of instabilities considered in classical electrodynamics of plasmas and plasmalike media is demonstrated.

  9. Solid consistency

    NASA Astrophysics Data System (ADS)

    Bordin, Lorenzo; Creminelli, Paolo; Mirbabayi, Mehrdad; Noreña, Jorge

    2017-03-01

    We argue that isotropic scalar fluctuations in solid inflation are adiabatic in the super-horizon limit. During the solid phase this adiabatic mode has peculiar features: constant energy-density slices and comoving slices do not coincide, and their curvatures, parameterized respectively by ζ and Script R, both evolve in time. The existence of this adiabatic mode implies that Maldacena's squeezed limit consistency relation holds after angular average over the long mode. The correlation functions of a long-wavelength spherical scalar mode with several short scalar or tensor modes is fixed by the scaling behavior of the correlators of short modes, independently of the solid inflation action or dynamics of reheating.

  10. SU-E-T-133: Assessing IMRT Treatment Delivery Accuracy and Consistency On a Varian TrueBeam Using the SunNuclear PerFraction EPID Dosimetry Software

    SciTech Connect

    Dieterich, S; Trestrail, E; Holt, R; Saini, S; Pfeiffer, I; Kent, M; Hansen, K

    2015-06-15

    Purpose: To assess if the TrueBeam HD120 collimator is delivering small IMRT fields accurately and consistently throughout the course of treatment using the SunNuclear PerFraction software. Methods: 7-field IMRT plans for 8 canine patients who passed IMRT QA using SunNuclear Mapcheck DQA were selected for this study. The animals were setup using CBCT image guidance. The EPID fluence maps were captured for each treatment field and each treatment fraction, with the first fraction EPID data serving as the baseline for comparison. The Sun Nuclear PerFraction Software was used to compare the EPID data for subsequent fractions using a Gamma (3%/3mm) pass rate of 90%. To simulate requirements for SRS, the data was reanalyzed using a Gamma (3%/1mm) pass rate of 90%. Low-dose, low- and high gradient thresholds were used to focus the analysis on clinically relevant parts of the dose distribution. Results: Not all fractions could be analyzed, because during some of the treatment courses the DICOM tags in the EPID images intermittently change from CU to US (unspecified), which would indicate a temporary loss of EPID calibration. This technical issue is still being investigated. For the remaining fractions, the vast majority (7/8 of patients, 95% of fractions, and 96.6% of fields) are passing the less stringent Gamma criteria. The more stringent Gamma criteria caused a drop in pass rate (90 % of fractions, 84% of fields). For the patient with the lowest pass rate, wet towel bolus was used. Another patient with low pass rates experienced masseter muscle wasting. Conclusion: EPID dosimetry using the PerFraction software demonstrated that the majority of fields passed a Gamma (3%/3mm) for IMRT treatments delivered with a TrueBeam HD120 MLC. Pass rates dropped for a DTA of 1mm to model SRS tolerances. PerFraction pass rates can flag missing bolus or internal shields. Sanjeev Saini is an employee of Sun Nuclear Corporation. For this study, a pre-release version of PerFRACTION 1

  11. Results of Bladder-Conserving Treatment, Consisting of Brachytherapy Combined With Limited Surgery and External Beam Radiotherapy, for Patients With Solitary T1-T3 Bladder Tumors Less Than 5 cm in Diameter

    SciTech Connect

    Blank, Leo; Koedooder, Kees; Os, Rob van; Kar, Marlou van de; Haitze van der Veen, J.; Koning, Caro

    2007-10-01

    Purpose: To evaluate the long-term, local relapse-free, distant metastasis-free, and overall survival rates in patients with a solitary bladder tumor <5 cm in diameter who were treated with external beam radiotherapy, limited surgery, and brachytherapy. Methods and Materials: The results of 122 patients after bladder-saving treatment were analyzed. After EBRT, the patients underwent cystotomy, and catheters were implanted. Of the 122 patients, 99 were treated with a continuous low-dose-rate technique and 23 patients with a pulsed-dose-rate technique. The median follow-up period was 5 years. Results: The 5-year local and distant relapse-free survival rate was 76% and 83%, respectively. The 5 and 10-year relapse-free survival rate was 69% and 66%, respectively. For overall survival, the corresponding rates were 73% and 49%. Toxicity was low. No differences were found between the continuous low-dose-rate and pulsed-dose-rate groups. Conclusion: The results of our study have shown that external beam radiotherapy followed by brachytherapy as a bladder-saving treatment for a selected group of patients with bladder cancer yields excellent local tumor control and low toxicity.

  12. BEAM-BEAM 2003 SUMMARY.

    SciTech Connect

    FISCHER,W.SEN,T.

    2003-05-19

    This paper summarizes the presentations and discussions of the Beam-Beam'03 workshop, held in Montauk, Long Island, from May 19 to 23, 2003. Presentations and discussions focused on halo generation from beam-beam interactions; beam-beam limits, especially coherent limits and their effects on existing and future hadron colliders; beam-beam compensation techniques, particularly for long-range interactions; and beam-beam study tools in theory, simulation, and experiment.

  13. A symplectic coherent beam-beam model

    SciTech Connect

    Furman, M.A.

    1989-05-01

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

  14. Consistent model driven architecture

    NASA Astrophysics Data System (ADS)

    Niepostyn, Stanisław J.

    2015-09-01

    The goal of the MDA is to produce software systems from abstract models in a way where human interaction is restricted to a minimum. These abstract models are based on the UML language. However, the semantics of UML models is defined in a natural language. Subsequently the verification of consistency of these diagrams is needed in order to identify errors in requirements at the early stage of the development process. The verification of consistency is difficult due to a semi-formal nature of UML diagrams. We propose automatic verification of consistency of the series of UML diagrams originating from abstract models implemented with our consistency rules. This Consistent Model Driven Architecture approach enables us to generate automatically complete workflow applications from consistent and complete models developed from abstract models (e.g. Business Context Diagram). Therefore, our method can be used to check practicability (feasibility) of software architecture models.

  15. Indexing Consistency and Quality.

    ERIC Educational Resources Information Center

    Zunde, Pranas; Dexter, Margaret E.

    A measure of indexing consistency is developed based on the concept of 'fuzzy sets'. It assigns a higher consistency value if indexers agree on the more important terms than if they agree on less important terms. Measures of the quality of an indexer's work and exhaustivity of indexing are also proposed. Experimental data on indexing consistency…

  16. Focused ion beam and field-emission microscopy of metallic filaments in memory devices based on thin films of an ambipolar organic compound consisting of oxadiazole, carbazole, and fluorene units

    USGS Publications Warehouse

    Pearson, Christopher; Bowen, Leon; Lee, Myung Won; Fisher, Alison L.; Linton, Katherine E.; Bryce, Martin R.; Petty, Michael C.

    2013-01-01

    We report on the mechanism of operation of organic thin film resistive memory architectures based on an ambipolar compound consisting of oxadiazole, carbazole, and fluorene units. Cross-sections of the devices have been imaged by electron microscopy both before and after applying a voltage. The micrographs reveal the growth of filaments, with diameters of 50 nm–100 nm, on the metal cathode. We suggest that these are formed by the drift of aluminium ions from the anode and are responsible for the observed switching and negative differential resistance phenomena in the memory devices.

  17. Focused ion beam and field-emission microscopy of metallic filaments in memory devices based on thin films of an ambipolar organic compound consisting of oxadiazole, carbazole, and fluorene units

    NASA Astrophysics Data System (ADS)

    Pearson, Christopher; Bowen, Leon; Lee, Myung-Won; Fisher, Alison L.; Linton, Katharine E.; Bryce, Martin R.; Petty, Michael C.

    2013-05-01

    We report on the mechanism of operation of organic thin film resistive memory architectures based on an ambipolar compound consisting of oxadiazole, carbazole, and fluorene units. Cross-sections of the devices have been imaged by electron microscopy both before and after applying a voltage. The micrographs reveal the growth of filaments, with diameters of 50 nm-100 nm, on the metal cathode. We suggest that these are formed by the drift of aluminium ions from the anode and are responsible for the observed switching and negative differential resistance phenomena in the memory devices.

  18. Lazy arc consistency

    SciTech Connect

    Schiex, T.; Gaspin, C.; Regin, J.C.; Verfaillie, G.

    1996-12-31

    Arc consistency filtering is widely used in the framework of binary constraint satisfaction problems: with a low complexity, inconsistency may be detected and domains are filtered. In this paper, we show that when detecting inconsistency is the objective, a systematic domain filtering is useless and a lazy approach is more adequate. Whereas usual arc consistency algorithms produce the maximum arc consistent sub-domain, when it exists, we propose a method, called LAC{tau}, which only looks for any arc consistent sub-domain. The algorithm is then extended to provide the additional service of locating one variable with a minimum domain cardinality in the maximum arc consistent sub-domain, without necessarily computing all domain sizes. Finally, we compare traditional AC enforcing and lazy AC enforcing using several benchmark problems, both randomly generated CSP and real life problems.

  19. Beam-beam simulations for separated beams

    SciTech Connect

    Furman, Miguel A.

    2000-04-10

    We present beam-beam simulation results from a strong-strong gaussian code for separated beams for the LHC and RHIC. The frequency spectrum produced by the beam-beam collisions is readily obtained and offers a good opportunity for experimental comparisons. Although our results for the emittance blowup are preliminary, we conclude that, for nominal parameter values, there is no significant difference between separated beams and center-on-center collisions.

  20. The GATOR2 Component Wdr24 Regulates TORC1 Activity and Lysosome Function

    PubMed Central

    Cai, Weili; Wei, Youheng; Jarnik, Michal; Reich, John; Lilly, Mary A.

    2016-01-01

    TORC1 is a master regulator of metabolism in eukaryotes that responds to multiple upstream signaling pathways. The GATOR complex is a newly defined upstream regulator of TORC1 that contains two sub-complexes, GATOR1, which inhibits TORC1 activity in response to amino acid starvation and GATOR2, which opposes the activity of GATOR1. While the GATOR1 complex has been implicated in a wide array of human pathologies including cancer and hereditary forms of epilepsy, the in vivo relevance of the GATOR2 complex remains poorly understood in metazoans. Here we define the in vivo role of the GATOR2 component Wdr24 in Drosophila. Using a combination of genetic, biochemical, and cell biological techniques we demonstrate that Wdr24 has both TORC1 dependent and independent functions in the regulation of cellular metabolism. Through the characterization of a null allele, we show that Wdr24 is a critical effector of the GATOR2 complex that promotes the robust activation of TORC1 and cellular growth in a broad array of Drosophila tissues. Additionally, epistasis analysis between wdr24 and genes that encode components of the GATOR1 complex revealed that Wdr24 has a second critical function, the TORC1 independent regulation of lysosome dynamics and autophagic flux. Notably, we find that two additional members of the GATOR2 complex, Mio and Seh1, also have a TORC1 independent role in the regulation of lysosome function. These findings represent a surprising and previously unrecognized function of GATOR2 complex components in the regulation of lysosomes. Consistent with our findings in Drosophila, through the characterization of a wdr24-/- knockout HeLa cell line we determined that Wdr24 promotes lysosome acidification and autophagic flux in mammalian cells. Taken together our data support the model that Wdr24 is a key effector of the GATOR2 complex, required for both TORC1 activation and the TORC1 independent regulation of lysosomes. PMID:27166823

  1. Network Consistent Data Association.

    PubMed

    Chakraborty, Anirban; Das, Abir; Roy-Chowdhury, Amit K

    2016-09-01

    Existing data association techniques mostly focus on matching pairs of data-point sets and then repeating this process along space-time to achieve long term correspondences. However, in many problems such as person re-identification, a set of data-points may be observed at multiple spatio-temporal locations and/or by multiple agents in a network and simply combining the local pairwise association results between sets of data-points often leads to inconsistencies over the global space-time horizons. In this paper, we propose a Novel Network Consistent Data Association (NCDA) framework formulated as an optimization problem that not only maintains consistency in association results across the network, but also improves the pairwise data association accuracies. The proposed NCDA can be solved as a binary integer program leading to a globally optimal solution and is capable of handling the challenging data-association scenario where the number of data-points varies across different sets of instances in the network. We also present an online implementation of NCDA method that can dynamically associate new observations to already observed data-points in an iterative fashion, while maintaining network consistency. We have tested both the batch and the online NCDA in two application areas-person re-identification and spatio-temporal cell tracking and observed consistent and highly accurate data association results in all the cases.

  2. Consistent Quantum Theory

    NASA Astrophysics Data System (ADS)

    Griffiths, Robert B.

    2001-11-01

    Quantum mechanics is one of the most fundamental yet difficult subjects in physics. Nonrelativistic quantum theory is presented here in a clear and systematic fashion, integrating Born's probabilistic interpretation with Schrödinger dynamics. Basic quantum principles are illustrated with simple examples requiring no mathematics beyond linear algebra and elementary probability theory. The quantum measurement process is consistently analyzed using fundamental quantum principles without referring to measurement. These same principles are used to resolve several of the paradoxes that have long perplexed physicists, including the double slit and Schrödinger's cat. The consistent histories formalism used here was first introduced by the author, and extended by M. Gell-Mann, J. Hartle and R. Omnès. Essential for researchers yet accessible to advanced undergraduate students in physics, chemistry, mathematics, and computer science, this book is supplementary to standard textbooks. It will also be of interest to physicists and philosophers working on the foundations of quantum mechanics. Comprehensive account Written by one of the main figures in the field Paperback edition of successful work on philosophy of quantum mechanics

  3. Consistent quantum measurements

    NASA Astrophysics Data System (ADS)

    Griffiths, Robert B.

    2015-11-01

    In response to recent criticisms by Okon and Sudarsky, various aspects of the consistent histories (CH) resolution of the quantum measurement problem(s) are discussed using a simple Stern-Gerlach device, and compared with the alternative approaches to the measurement problem provided by spontaneous localization (GRW), Bohmian mechanics, many worlds, and standard (textbook) quantum mechanics. Among these CH is unique in solving the second measurement problem: inferring from the measurement outcome a property of the measured system at a time before the measurement took place, as is done routinely by experimental physicists. The main respect in which CH differs from other quantum interpretations is in allowing multiple stochastic descriptions of a given measurement situation, from which one (or more) can be selected on the basis of its utility. This requires abandoning a principle (termed unicity), central to classical physics, that at any instant of time there is only a single correct description of the world.

  4. Cartesian beams.

    PubMed

    Bandres, Miguel A; Gutiérrez-Vega, Julio C

    2007-12-01

    A new and very general beam solution of the paraxial wave equation in Cartesian coordinates is presented. We call such a field a Cartesian beam. The complex amplitude of the Cartesian beams is described by either the parabolic cylinder functions or the confluent hypergeometric functions, and the beams are characterized by three parameters that are complex in the most general situation. The propagation through complex ABCD optical systems and the conditions for square integration are studied in detail. Applying the general expression of the Cartesian beams, we also derive two new and meaningful beam structures that, to our knowledge, have not yet been reported in the literature. Special cases of the Cartesian beams are the standard, elegant, and generalized Hermite-Gauss beams, the cosine-Gauss beams, the Lorentz beams, and the fractional order beams.

  5. Head-on beam-beam compensation in RHIC

    SciTech Connect

    Fischer, W.; Heimerle, M.; Luo, Y.; Pikin, A.; Beebe, E.; Bruno, D.; Gassner, D.; Gu, X.; Gupta, R. C.; Hock, J.; Jain, A.; Lambiase, R.; Mapes., M.; Meng, W.; Montag, C.; Oerter, B.; Okamura, M.; Raparia, D.; Tan, Y.; Than, R.; Tuozzolo, J.; Zhang, w.

    2010-07-29

    Head-on beam-beam compensation with electron lenses had been proposed for the SSC, LHC, and the Tevatron [1,2]. Two electron lenses are installed in the Tevatron [2-4], where they are routinely used as gap cleaner and have been tested in many other configurations. In RHIC there are 2 head-on beam-beam interactions at IP6 and IP8, and 4 long-range beam-beam interactions with large separation (10 mm) at the other IPs. We consider the partial indirect compensation of the head-on beam-beam effect with one electron lens in each ring. Together with intensity and emittance upgrades [5,6] our goal is to approximately double the luminosity over what can be achieved without these upgrades. A RHIC electron lens consists of: a DC electron gun, an electron beam transport to the main solenoid, the superconducting main solenoid in which the interaction with the hadron beam occurs, an electron beam transport to the collector, and an electron collector. The 2 electron lenses are located in IR10 between the DX beam separation dipoles. The proton beams pass through the main solenoids of both electron lenses, and interact head-on with one of them. The following is a slightly modified version of Ref. [7]. The table shows the main parameters of the proton beam and the electron lenses. References [8-11] present simulations for and discuss beam dynamics problems.

  6. Beam-beam experience in RHIC

    SciTech Connect

    Montag, C.; Heimerle, M.

    2010-07-29

    The Relativistic Heavy Ion Collider RHIC consists of two superconducting storage rings that intersect at six locations around the ring circumference. Two of these interaction regions are currently equipped with experiment detectors, namely STAR at the “6 o’clock” interaction point (IP), and PHENIX at “8 o’clock”. The two beams collide only at these two interaction regions, while they are vertically separated by typically 6-10mm at the other IPs. Together with the separator dipoles located at roughly 10m from the IP, and a distance between bunches of 30m, this avoids any parasitic beam-beam collisions. RHIC is capable of colliding any ion species at magnetic rigidities up to B × r = 830T × m , corresponding to 250 GeV for proton beams, or 100 GeV/n for fully stripped gold ions.

  7. Magnetic beam position monitor

    SciTech Connect

    Varfolomeev, A.A.; Ivanchenkov, S.N.; Khlebnikov, A.S.

    1995-12-31

    Many nondestructive beam position monitors are known. However, these devices can not be used for DC particle beam diagnostics. We investigated a method of beam diagnostics applicable for the operative control of DC high power e-beam inside closed waveguide. A design of the detector for determination of{open_quote} center of mass {close_quote} position of DC particle beam was developed. It was shown that the monitor can be used as a nondestructive method for the beam position control in resonators. Magnetic field of the particle beam outside a resonator is used. The detector consists of the steel yokes and magnetic field sensors. The sensors measure magnetic fluxes in the steel yokes fixed outside the resonator. When the particle beam changes its position, these magnetic fluxes also change. Beam displacement sensitivity of the monitor depends on the steel yoke dimensions. The detector sensitivity is equal to 1 Gauss/mm for the conditions adequate to the FOM-FEM project.

  8. Methods of beam cooling

    SciTech Connect

    Sessler, A.M.

    1996-02-01

    Diverse methods which are available for particle beam cooling are reviewed. They consist of some highly developed techniques such as radiation damping, electron cooling, stochastic cooling and the more recently developed, laser cooling. Methods which have been theoretically developed, but not yet achieved experimentally, are also reviewed. They consist of ionization cooling, laser cooling in three dimensions and stimulated radiation cooling.

  9. Measurement of T1 of the Ultrashort T2* Components in White Matter of the Brain at 3T

    PubMed Central

    Du, Jiang; Sheth, Vipul; He, Qun; Carl, Michael; Chen, Jun; Corey-Bloom, Jody; Bydder, Graeme M.

    2014-01-01

    Recent research demonstrates that white matter of the brain contains not only long T2 components, but a minority of ultrashort T2* components. Adiabatic inversion recovery prepared dual echo ultrashort echo time (IR-dUTE) sequences can be used to selectively image the ultrashort T2* components in white matter of the brain using a clinical whole body scanner. The T2*s of the ultrashort T2* components can be quantified using mono-exponential decay fitting of the IR-dUTE signal at a series of different TEs. However, accurate T1 measurement of the ultrashort T2* components is technically challenging. Efficient suppression of the signal from the majority of long T2 components is essential for robust T1 measurement. In this paper we describe a novel approach to this problem based on the use of IR-dUTE data acquisitions with different TR and TI combinations to selectively detect the signal recovery of the ultrashort T2* components. Exponential recovery curve fitting provides efficient T1 estimation, with minimized contamination from the majority of long T2 components. A rubber phantom and a piece of bovine cortical bone were used for validation of this approach. Six healthy volunteers were studied. An averaged T2* of 0.32±0.09 ms, and a short mean T1 of 226±46 ms were demonstrated for the healthy volunteers at 3T. PMID:25093859

  10. Beam diagnostics

    SciTech Connect

    Bogaty, J.; Clifft, B.E.; Zinkann, G.P.; Pardo, R.C.

    1995-08-01

    The ECR-PII injector beam line is operated at a fixed ion velocity. The platform high voltage is chosen so that all ions have a velocity of 0.0085c at the PII entrance. If a previous tune configuration for the linac is to be used, the beam arrival time must be matched to the previous tune as well. A nondestructive beam-phase pickup detector was developed and installed at the entrance to the PII linac. This device provides continuous phase and beam current information and allows quick optimization of the beam injected into PII. Bunches traverse a short tubular electrode thereby inducing displacement currents. These currents are brought outside the vacuum interface where a lumped inductance resonates electrode capacitance at one of the bunching harmonic frequencies. This configuration yields a basic sensitivity of a few hundred millivolts signal per microampere of beam current. Beam-induced radiofrequency signals are summed against an offset frequency generated by our master oscillator. The resulting kilohertz difference frequency conveys beam intensity and bunch phase information which is sent to separate processing channels. One channel utilizes a phase locked loop which stabilizes phase readings if beam is unstable. The other channel uses a linear full wave active rectifier circuit which converts kilohertz sine wave signal amplitude to a D.C. voltage representing beam current. A prototype set of electronics is now in use with the detector and we began to use the system in operation to set the arrival beam phase. A permanent version of the electronics system for the phase detector is now under construction. Additional nondestructive beam intensity and phase monitors at the {open_quotes}Booster{close_quotes} and {open_quotes}ATLAS{close_quotes} linac sections are planned as well as on some of the high-energy beam lines. Such a monitor will be particularly useful for FMA experiments where the primary beam hits one of the electric deflector plates.

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

    SciTech Connect

    Paynter, D.; Weston, S. J.; Cosgrove, V. P.; Evans, J. A.; Thwaites, D. I.

    2014-05-15

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

  12. DNMT3b Modulates Melanoma Growth by Controlling Levels of mTORC2 Component RICTOR.

    PubMed

    Micevic, Goran; Muthusamy, Viswanathan; Damsky, William; Theodosakis, Nicholas; Liu, Xiaoni; Meeth, Katrina; Wingrove, Emily; Santhanakrishnan, Manjula; Bosenberg, Marcus

    2016-03-08

    DNA methyltransferase DNMT3B is frequently overexpressed in tumor cells and plays important roles during the formation and progression of several cancer types. However, the specific signaling pathways controlled by DNMT3B in cancers, including melanoma, are poorly understood. Here, we report that DNMT3B plays a pro-tumorigenic role in human melanoma and that DNMT3B loss dramatically suppresses melanoma formation in the Braf/Pten mouse melanoma model. Loss of DNMT3B results in hypomethylation of the miR-196b promoter and increased miR-196b expression, which directly targets the mTORC2 component Rictor. Loss of RICTOR in turn prevents mTORC2 activation, which is critical for melanoma formation and growth. These findings establish Dnmt3b as a regulator of melanoma formation through its effect on mTORC2 signaling. Based on these results, DNMT3B is a potential therapeutic target in melanoma.

  13. Prokaryotic 2-component systems and the OmpR/PhoB superfamily.

    PubMed

    Nguyen, Minh-Phuong; Yoon, Joo-Mi; Cho, Man-Ho; Lee, Sang-Won

    2015-11-01

    In bacteria, 2-component regulatory systems (TCSs) are the critical information-processing pathways that link stimuli to specific adaptive responses. Signals perceived by membrane sensors, which are generally histidine kinases, are transmitted by response regulators (RRs) to allow cells to cope rapidly and effectively with environmental challenges. Over the past few decades, genes encoding components of TCSs and their responsive proteins have been identified, crystal structures have been described, and signaling mechanisms have been elucidated. Here, we review recent findings and interesting breakthroughs in bacterial TCS research. Furthermore, we discuss structural features, mechanisms of activation and regulation, and cross-regulation of RRs, with a focus on the largest RR family, OmpR/PhoB, to provide a comprehensive overview of these critically important signaling molecules.

  14. Beam-energy inequality in the beam-beam interaction

    SciTech Connect

    Krishnagopal, S.; Siemann, R. )

    1990-03-01

    Conditions for energy transparency,'' unequal-energy beams having the same beam-beam behavior, are derived for round beams from a Hamiltonian model of the beam-beam interaction. These conditions are equal fractional betatron tunes, equal synchrotron tunes, equal beam-beam strength parameters, equal nominal sizes, equal {beta}{sup *}'s and equal bunch lengths. With these conditions the only way to compensate for unequal energies is with the number of particles per bunch.

  15. Self-esteem modulates the latency of P2 component in implicit self-relevant processing.

    PubMed

    Yang, Juan; Qi, Mingming; Guan, Lili

    2014-03-01

    Previous study has shown that the latency of P2 component was more prolonged in processing self-relevant words compared to processing non-self-relevant words. However, the prolonged P2 latency may index the self-relevance of the words, the valence of the words, or an interaction of the two. The present study aimed to (1) further clarify the specific psychological significance of the prolonged P2 latency in implicit self-processing and (2) investigate the potential association between self-esteem and the latency of P2 in processing implicit self-relevant information. Nineteen participants were examined using event-related potentials (ERPs) technology. They were exposed to positive and negative words and were asked to make a judgment about the color of each word. For the data analysis, words were grouped individually according to their degree of self-relevance (low vs. high) for each participant. Results showed that the latency of P2 was more prolonged in processing the negative-high self-relevant words compared to processing the positive-high self-relevant words. Also, self-esteem was negatively correlated with the P2 latency in processing negative-high self-relevant words. Overall, the results of the present study suggested that levels of self-esteem might modulate neural correlates of self-referential processing.

  16. Development of 3D beam-beam simulation for the Tevatron

    SciTech Connect

    Stern, E.; Amundson, J.; Spentzouris, P.; Valishev, A.; Qiang, J.; Ryne, R.; /LBL, Berkeley

    2007-06-01

    We present status of development of a 3D Beam-Beam simulation code for simulating the Fermilab Tevatron collider. The essential features of the code are 3D particle-in-cell Poisson solver for calculating the Beam-Beam electromagnetic interactions with additional modules for linear optics, machine impedance and chromaticity, and multiple bunch tracking. The simulations match synchrobetatron oscillations measured at the VEPP-2M collider. The impedance calculations show beam instability development consistent with analytic expressions.

  17. Beam tuning

    SciTech Connect

    Pardo, R.C.; Zinkann, G.P.

    1995-08-01

    A program for configuring the linac, based on previously run configurations for any desired beam was used during the past year. This program uses only a small number of empirical tunes to scale resonator fields to properly accelerate a beam with a different charge-to-mass (q/A) ratio from the original tune configuration. The program worked very well for the PII linac section where we can easily match a new beam`s arrival phase and velocity to the tuned value. It was also fairly successful for the Booster and ATLAS sections of the linac, but not as successful as for the PII linac. Most of the problems are associated with setting the beam arrival time correctly for each major linac section. This problem is being addressed with the development of the capacitive pickup beam phase monitor discussed above. During the next year we expect to improve our ability to quickly configure the linac for new beams and reduce the time required for linac tuning. Already the time required for linac tuning as a percentage of research hours has decreased from 22% in FY 1993 to 15% in the first quarter of FY 1995.

  18. Foldable beam

    NASA Technical Reports Server (NTRS)

    Hedgepeth, J. M.; Coyner, J. V.; Crawford, R. F.

    1981-01-01

    A foldable beam possessing superior qualities of light weight, compactness for transportation, quick deployment with minimum use of force, and high strength is described. These qualities are achieved through the use of a series of longitudinally rigid segments, hinged along one side and threaded by one or two cables along the opposite side. Tightening the cables holds the beam extended. Loosening the cables permits the segments to fold away from the threaded side. In one embodiment the segments are connected by canted hinges with the result that the beam may be folded in a helix-like configuration around a cylinder. In another embodiment the segments themselves may be hinged to fold flat laterally as the beam is folded, resulting in a configuration that may be helixed around a shorter cylinder.

  19. Beam-beam deflection and signature curves for elliptic beams

    SciTech Connect

    Ziemann, V.

    1990-10-22

    In this note we will present closed expressions for the beam-beam deflection angle for arbitrary elliptic beams including tilt. From these expressions signature curves, i.e., systematic deviations from the round beam deflection curve due to ellipticity or tilt are derived. In the course of the presentation we will prove that it is generally impossible to infer individual beam sizes from beam-beam deflection scans. 3 refs., 2 figs.

  20. Consistency argued students of fluid

    NASA Astrophysics Data System (ADS)

    Viyanti; Cari; Suparmi; Winarti; Slamet Budiarti, Indah; Handika, Jeffry; Widyastuti, Fatma

    2017-01-01

    Problem solving for physics concepts through consistency arguments can improve thinking skills of students and it is an important thing in science. The study aims to assess the consistency of the material Fluid student argmentation. The population of this study are College students PGRI Madiun, UIN Sunan Kalijaga Yogyakarta and Lampung University. Samples using cluster random sampling, 145 samples obtained by the number of students. The study used a descriptive survey method. Data obtained through multiple-choice test and interview reasoned. Problem fluid modified from [9] and [1]. The results of the study gained an average consistency argmentation for the right consistency, consistency is wrong, and inconsistent respectively 4.85%; 29.93%; and 65.23%. Data from the study have an impact on the lack of understanding of the fluid material which is ideally in full consistency argued affect the expansion of understanding of the concept. The results of the study as a reference in making improvements in future studies is to obtain a positive change in the consistency of argumentations.

  1. Simulation of beam-induced plasma for the mitigation of beam-beam effects

    SciTech Connect

    Ma, J.; Wang, G.; Samulyak, R.; Yu, K.; Litvinenko, V.

    2015-05-03

    One of the main challenges in the increase of luminosity of circular colliders is the control of the beam-beam effect. In the process of exploring beam-beam mitigation methods using plasma, we evaluated the possibility of plasma generation via ionization of neutral gas by proton beams, and performed highly resolved simulations of the beam-plasma interaction using SPACE, a 3D electromagnetic particle-in-cell code. The process of plasma generation is modelled using experimentally measured cross-section coefficients and a plasma recombination model that takes into account the presence of neutral gas and beam-induced electromagnetic fields. Numerically simulated plasma oscillations are consistent with theoretical analysis. In the beam-plasma interaction process, high-density neutral gas reduces the mean free path of plasma electrons and their acceleration. A numerical model for the drift speed as a limit of plasma electron velocity was developed. Simulations demonstrate a significant reduction of the beam electric field in the presence of plasma. Preliminary simulations using fully-ionized plasma have also been performed and compared with the case of beam-induced plasma.

  2. Beam experiments related to the head-on beam-beam compensation project at RHIC

    SciTech Connect

    Montag, C.; Bai, M.; Drees, A.; Fischer, W.; Marusic, A.; Wang, G.

    2011-03-28

    Beam experiments have been performed in RHIC to determine some key parameters of the RHIC electron lenses, and to test the capability of verifying lattice modifications by beam measurements. We report the status and recent results of these experiments. The Relativistic Heavy Ion Collider (RHIC) consists of two superconducting storage rings that intersect at six locations around its circumference. Beams collide in interaction points (IPs) 6 and 8, which are equipped with the detectors STAR and PHENIX, respectively (Fig. 1). With the polarized proton working point constrained between 2/3 and 7/10 to achieve good luminosity lifetime and maintain polarization, the proton bunch intensity is limited to 2 {center_dot} 10{sup 11} protons per bunch by the resulting beam-beam tuneshift. To overcome this limitation, installation of an electron lens in IP 10 is foreseen to partially compensate the beam-beam effect and reduce the beam-beam tuneshift parameter. As part of this project, beam experiments are being performed at RHIC to determine key parameters of the electron lens as well as to verify lattice modifications.

  3. Beam wander relieved orbital angular momentum communication in turbulent atmosphere using Bessel beams

    PubMed Central

    Yuan, Yangsheng; Lei, Ting; Li, Zhaohui; Li, Yangjin; Gao, Shecheng; Xie, Zhenwei; Yuan, Xiaocong

    2017-01-01

    Optical beam wander is one of the most important issues for free-space optical (FSO) communication. We theoretically derive a beam wander model for Bessel beams propagating in turbulent atmosphere. The calculated beam wander of high order Bessel beams with different turbulence strengths are consistent with experimental measurements. Both theoretical and experimental results reveal that high order Bessel beams are less influenced by the turbulent atmosphere. We also demonstrate the Bessel beams based orbital angular momentum (OAM) multiplexing/demultiplexing in FSO communication with atmospheric turbulence. Under the same atmospheric turbulence condition, the bit error rates of transmitted signals carried by high order Bessel beams show smaller values and fluctuations, which indicates that the high order Bessel beams have an advantage of mitigating the beam wander in OAM multiplexing FSO communication. PMID:28186198

  4. Beam wander relieved orbital angular momentum communication in turbulent atmosphere using Bessel beams

    NASA Astrophysics Data System (ADS)

    Yuan, Yangsheng; Lei, Ting; Li, Zhaohui; Li, Yangjin; Gao, Shecheng; Xie, Zhenwei; Yuan, Xiaocong

    2017-02-01

    Optical beam wander is one of the most important issues for free-space optical (FSO) communication. We theoretically derive a beam wander model for Bessel beams propagating in turbulent atmosphere. The calculated beam wander of high order Bessel beams with different turbulence strengths are consistent with experimental measurements. Both theoretical and experimental results reveal that high order Bessel beams are less influenced by the turbulent atmosphere. We also demonstrate the Bessel beams based orbital angular momentum (OAM) multiplexing/demultiplexing in FSO communication with atmospheric turbulence. Under the same atmospheric turbulence condition, the bit error rates of transmitted signals carried by high order Bessel beams show smaller values and fluctuations, which indicates that the high order Bessel beams have an advantage of mitigating the beam wander in OAM multiplexing FSO communication.

  5. Coherent beam-beam interaction with four colliding beams

    NASA Astrophysics Data System (ADS)

    Podobedov, B.; Siemann, R. H.

    1995-09-01

    The coherent beam-beam interaction in the absence of Landau damping is studied with a computer simulation of four space-charge-compensated colliding beams. Results are presented for the modes, phase space structures, widths, and growth rates of coherent beam-beam resonances. These results are compared with solutions of the Vlasov equation, and with measurements made at the Dispositif de Collisions dans l'Igloo (DCI) storage ring in Orsay, France, which operated with space-charge-compensated colliding beams.

  6. BEAM-BEAM SIMULATIONS FOR DOUBLE-GAUSSIAN BEAMS.

    SciTech Connect

    MONTAG, C.; MALITSKY, N.; BEN-ZVI, I.; LITVINENKO, V.

    2005-05-16

    Electron cooling together with intra-beam scattering results in a transverse distribution that can best be described by a sum of two gaussians, one for the high-density core and one for the tails of the distribution. Simulation studies are being performed to understand the beam-beam interaction of these double-gaussian beams. Here we report the effect of low-frequency random tune modulations on diffusion in double-gaussian beams and compare the effects to those in beam-beam interactions with regular gaussian beams and identical tune shift parameters.

  7. Consistent transport coefficients in astrophysics

    NASA Technical Reports Server (NTRS)

    Fontenla, Juan M.; Rovira, M.; Ferrofontan, C.

    1986-01-01

    A consistent theory for dealing with transport phenomena in stellar atmospheres starting with the kinetic equations and introducing three cases (LTE, partial LTE, and non-LTE) was developed. The consistent hydrodynamical equations were presented for partial-LTE, the transport coefficients defined, and a method shown to calculate them. The method is based on the numerical solution of kinetic equations considering Landau, Boltzmann, and Focker-Planck collision terms. Finally a set of results for the transport coefficients derived for a partially ionized hydrogen gas with radiation was shown, considering ionization and recombination as well as elastic collisions. The results obtained imply major changes is some types of theoretical model calculations and can resolve some important current problems concerning energy and mass balance in the solar atmosphere. It is shown that energy balance in the lower solar transition region can be fully explained by means of radiation losses and conductive flux.

  8. Postural consistency in skilled archers.

    PubMed

    Stuart, J; Atha, J

    1990-01-01

    The consistency of an archer's postural set at the moment of loose (arrow release) is commonly perceived to be an important determinant of success. The coach seeks, among other things, to provide the archer with information about postural consistency, details of which he acquires by eye or occasionally by video-recordings. The gains that might be achieved from more precise information are examined here. Nine skilled archers, classified into either skilled or elite groups according to their officially computed handicap, were continuously monitored and measured with a three-dimensional co-ordinate analyser (Charnwood Dynamics Coda-3 Scanner) while shooting two ends (series) of three arrows each. Considerable variability was observed in the precision with which the positions of head, elbow and bow at the moment of loose were replicated by archers of similar levels of skill. These results are interpreted to suggest that precise postural consistency may not be the primary feature distinguishing between the performance of archers at the higher skill levels.

  9. Consistent interpretations of quantum mechanics

    SciTech Connect

    Omnes, R. )

    1992-04-01

    Within the last decade, significant progress has been made towards a consistent and complete reformulation of the Copenhagen interpretation (an interpretation consisting in a formulation of the experimental aspects of physics in terms of the basic formalism; it is consistent if free from internal contradiction and complete if it provides precise predictions for all experiments). The main steps involved decoherence (the transition from linear superpositions of macroscopic states to a mixing), Griffiths histories describing the evolution of quantum properties, a convenient logical structure for dealing with histories, and also some progress in semiclassical physics, which was made possible by new methods. The main outcome is a theory of phenomena, viz., the classically meaningful properties of a macroscopic system. It shows in particular how and when determinism is valid. This theory can be used to give a deductive form to measurement theory, which now covers some cases that were initially devised as counterexamples against the Copenhagen interpretation. These theories are described, together with their applications to some key experiments and some of their consequences concerning epistemology.

  10. Task Versus Component Consistency in the Development of Automatic Processes: Consistent Attending Versus Consistent Responding.

    DTIC Science & Technology

    1982-03-01

    a visual search paradigm, Schneider and Shiffrin (1977, Experiment 2) found that reaction times in conditions where subjects could consistently attend...requires less effort, is more accurate and is faster (see for example, Corballis, 1975; Egeth, Atkinson , Gilmore, & Marcus, 1973; Kristofferson, 1972...Logan, 1978, 1979; Neisser, 1974; Schneider & Shiffrin , 1977; Shiffrin & Schneider, 1977; Schneider & Fisk, in press - a; for a review, see Schneider

  11. STATUS OF THE RHIC HEAD-ON BEAM-BEAM COMPENSATION PROJECT

    SciTech Connect

    Fischer, W.; Luo, Y.; Pikin, A.; Beebe, E.; Bruno, D.; Gassner, D.; Hocke, J.; Jain, A.; Lambiase, R.; Mapes, M.; Meng, W.; Montag, C.; Oerter, B.; Okamura, M.; Raparia, D.; Than, R.; Tuozzolo, J.

    2010-05-23

    In polarized proton operation the luminosity of RHIC is limited by the head-on beam-beam effect, and methods that mitigate the effect will result in higher peak and average luminosities. Two electron lenses, one for each ring, are being constructed to partially compensate the head-on beam-beam effect in the two rings. An electron lens consists of a low energy electron beam that creates the same amplitude dependent transverse kick as the proton beam. We discuss design considerations and present the main parameters.

  12. FFAG Beam Line for nuPIL - Neutrinos from PIon Beam Line

    SciTech Connect

    Lagrange, Jean-Baptiste; Pasternak, Jaroslaw; Bross, Alan; Liu, Ao; Appleby, Robert; Tygier, Sam

    2016-06-01

    The Long Baseline Neutrino Facilities (LBNF) program aims to deliver a neutrino beam for the Deep Underground Neutrino Experiment (DUNE). The current baseline for LBNF is a conventional magnetic horn and decay pipe system. Neutrinos from PIon beam Line (nuPIL) is a part of the optimization effort to optimize the LBNF. It consists of a pion beam line after the horn to clean the beam of high energy protons and wrong-sign pions before transporting them into a decay beam line, where instrumentation could be implemented. This paper focuses on the FFAG solution for this pion beam line. The resulting neutrino flux is also presented.

  13. A Low-Mass H2 Component to the AU Microscopii Circumstellar Disk

    NASA Astrophysics Data System (ADS)

    France, Kevin; Roberge, Aki; Lupu, Roxana E.; Redfield, Seth; Feldman, Paul D.

    2007-10-01

    We present a determination of the molecular gas mass in the AU Microscopii circumstellar disk. Direct detection of a gas component to the AU Mic disk has proven elusive, with upper limits derived from ultraviolet absorption line and submillimeter CO emission studies. Fluorescent emission lines of H2, pumped by the O VI λ1032 resonance line through the C-X (1-1) Q(3) λ1031.87 Å transition, are detected by the Far Ultraviolet Spectroscopic Explorer. These lines are used to derive the H2 column density associated with the AU Mic system. The derived column density is in the range N(H2)=1.9×1017 to 2.8×1015 cm-2, roughly 2 orders of magnitude lower than the upper limit inferred from absorption line studies. This range of column densities reflects the range of H2 excitation temperature consistent with the observations, T(H2)=800-2000 K, derived from the presence of emission lines excited by O VI in the absence of those excited by Lyα. Within the observational uncertainties, the data are consistent with the H2 gas residing in the disk. The inferred N(H2) range corresponds to H2-to-dust ratios of <~1/30:1 and a total M(H2)=4.0×10-4 to 5.8×10-6 M⊕. We use these results to predict the intensity of the associated rovibrational emission lines of H2 at infrared wavelengths covered by ground-based instruments, HST NICMOS, and the Spitzer IRS. Based in part on observations made with the Far Ultraviolet Spectroscopic Explorer, operated by the Johns Hopkins University for NASA.

  14. Surrogate measures and consistent surrogates.

    PubMed

    Vanderweele, Tyler J

    2013-09-01

    Surrogates which allow one to predict the effect of the treatment on the outcome of interest from the effect of the treatment on the surrogate are of importance when it is difficult or expensive to measure the primary outcome. Unfortunately, the use of such surrogates can give rise to paradoxical situations in which the effect of the treatment on the surrogate is positive, the surrogate and outcome are strongly positively correlated, but the effect of the treatment on the outcome is negative, a phenomenon sometimes referred to as the "surrogate paradox." New results are given for consistent surrogates that extend the existing literature on sufficient conditions that ensure the surrogate paradox is not manifest. Specifically, it is shown that for the surrogate paradox to be manifest it must be the case that either there is (i) a direct effect of treatment on the outcome not through the surrogate and in the opposite direction as that through the surrogate or (ii) confounding for the effect of the surrogate on the outcome, or (iii) a lack of transitivity so that treatment does not positively affect the surrogate for all the same individuals for whom the surrogate positively affects the outcome. The conditions for consistent surrogates and the results of the article are important because they allow investigators to predict the direction of the effect of the treatment on the outcome simply from the direction of the effect of the treatment on the surrogate. These results on consistent surrogates are then related to the four approaches to surrogate outcomes described by Joffe and Greene (2009, Biometrics 65, 530-538) to assess whether the standard criteria used by these approaches to assess whether a surrogate is "good" suffice to avoid the surrogate paradox.

  15. Hybrid laser-beam-shaping system for rotatable dual beams with long depth of focus

    NASA Astrophysics Data System (ADS)

    Chou, Fu-Lung; Chen, Cheng-Huan; Lin, Yu-Chung; Lin, Mao-Chi

    2016-10-01

    A laser processing system consisting of two diffractive elements and one refractive element is proposed enabling a Gaussian laser beam to be transformed into two beams with a depth of focus of up to 150 µm and focal spot smaller than 5 µm. For specific laser processing, the two beams are rotatable when the beam-splitting diffractive element is rotated. The overall system is versatile for laser cutting and drilling.

  16. Theoretical and Experimental Beam Plasma Physics (TEBPP)

    NASA Technical Reports Server (NTRS)

    Roberts, B.

    1986-01-01

    The theoretical and experimental beam plasma physics (TEBPP) consists of a package of five instruments to measure electric and magnetic fields, plasma density and temperature, neutral density, photometric emissions, and energetic particle spectra during firings of the particle injector (SEPAC) electron beam. The package is developed on a maneuverable boom (or RMS) and is used to measure beam characteristics and induced perturbations field ( 10 m) and mid field ( 10 m to 100 m) along the electron beam. The TEBPP package will be designed to investigate induced oscillations and induced electromagnetic mode waves, neutral and ion density and temperature effects, and beam characteristics as a function of axial distance.

  17. Theoretical and Experimental Beam Plasma Physics (TEBPP)

    NASA Technical Reports Server (NTRS)

    Roberts, W. T.

    1985-01-01

    The theoretical and experimental beam plasma physics (TEBPP) consists of a package of five instruments to measure electric and magnetic fields, plasma density and temperature, neutral density, photometric emissions, and energetic particle spectra during firings of the particle injector (SEPAC) electron beam. The package is deployed on a maneuverable boom (or RMS) and is used to measure beam characteristics and induced perturbations in the near field ( 10 m) and mid field (10 m to 100 m) along the electron beam. The TEBPP package will be designed to investigate induced oscillations and induced electromagnetic mode waves, neutral and ion density and temperature effects, and beam characteristics as a function of axial distance.

  18. Adjustment procedure for beam alignment in scanned ion-beam therapy

    NASA Astrophysics Data System (ADS)

    Saraya, Y.; Takeshita, E.; Furukawa, T.; Hara, Y.; Mizushima, K.; Saotome, N.; Tansho, R.; Shirai, T.; Noda, K.

    2016-09-01

    Control of the beam position for three-dimensional pencil-beam scanning is important because the position accuracy of the beam significantly impacts the alignment of the irradiation field. To suppress this effect, we have developed a simple procedure for beamline tuning. At first, beamline tuning is performed with steering magnets and fluorescent screen monitors to converge the beam's trajectory to a central orbit. Misalignment between the beam's position and the reference axis is checked by using the verification system, which consists of a screen monitor and an acrylic phantom. If the beam position deviates from the reference axis, two pairs of steering magnets, which are placed on downstream of the beam transport line, will be corrected. These adjustments are iterated until the deviations for eleven energies of the beam are within 0.5 mm of the reference axis. To demonstrate the success of our procedure, we used our procedure to perform beam commissioning at the Kanagawa Cancer Center.

  19. Self-consistent undulator radiation via Lienard-Wiechert fields

    NASA Astrophysics Data System (ADS)

    Elias, Luis R.; Tecimer, Musit; Kimel, Isidoro

    1995-09-01

    Using Lienard-Wiechert fields and the Lorentz Force relation we present self consistent 3D radiation studies of electron beams moving through periodic electromagnetic structures such as those present in synchrotrons and free-electron laser undulators. Besides providing an economical means of calculating 3D vector radiation fields, our approach yields new insights into individual electron motion as it is driven by both, the velocity fields (Coulomb Fields) and the radiation fields generated by other electrons. We present results of electron beam compression resulting from longitudinal radiation forces competing in opposition with repulsive velocity field forces. We discuss results of noiseless 3D Self Amplified Spontaneous Emission in the X-Ray region resulting from the interaction of a filamentary electron beam with a circularly polarized magnetic undulator.

  20. Coherent beam-beam effects, theory & observations

    SciTech Connect

    Yuri I Alexahin

    2003-07-16

    Current theoretical understanding of the coherent beam-beam effect as well as its experimental observations are discussed: conditions under which the coherent beambeam modes may appear, possibility of their resonant interaction (coherent resonances), stability of beam-beam oscillations in the presence of external impedances. A special attention is given to the coherent beam-beam modes of finite length bunches: the synchro-betatron coupling is shown to provide reduction in the coherent tuneshift and--at the synchrotron tune values smaller than the beam-beam parameter--Landau damping by overlapping synchrotron satellites.

  1. Maintaining consistency in distributed systems

    NASA Technical Reports Server (NTRS)

    Birman, Kenneth P.

    1991-01-01

    In systems designed as assemblies of independently developed components, concurrent access to data or data structures normally arises within individual programs, and is controlled using mutual exclusion constructs, such as semaphores and monitors. Where data is persistent and/or sets of operation are related to one another, transactions or linearizability may be more appropriate. Systems that incorporate cooperative styles of distributed execution often replicate or distribute data within groups of components. In these cases, group oriented consistency properties must be maintained, and tools based on the virtual synchrony execution model greatly simplify the task confronting an application developer. All three styles of distributed computing are likely to be seen in future systems - often, within the same application. This leads us to propose an integrated approach that permits applications that use virtual synchrony with concurrent objects that respect a linearizability constraint, and vice versa. Transactional subsystems are treated as a special case of linearizability.

  2. Consistency of warm k -inflation

    NASA Astrophysics Data System (ADS)

    Peng, Zhi-Peng; Yu, Jia-Ning; Zhu, Jian-Yang; Zhang, Xiao-Min

    2016-11-01

    We extend k -inflation which is a type of kinetically driven inflationary model under the standard inflationary scenario to a possible warm inflationary scenario. The dynamical equations of this warm k -inflation model are obtained. We rewrite the slow-roll parameters which are different from the usual potential driven inflationary models and perform a linear stability analysis to give the proper slow-roll conditions in warm k -inflation. Two cases, a power-law kinetic function and an exponential kinetic function, are studied, when the dissipative coefficient Γ =Γ0 and Γ =Γ (ϕ ), respectively. A proper number of e-folds is obtained in both concrete cases of warm k -inflation. We find a constant dissipative coefficient (Γ =Γ0) is not a workable choice for these two cases while the two cases with Γ =Γ (ϕ ) are self-consistent warm inflationary models.

  3. Self-consistent triaxial models

    NASA Astrophysics Data System (ADS)

    Sanders, Jason L.; Evans, N. Wyn

    2015-11-01

    We present self-consistent triaxial stellar systems that have analytic distribution functions (DFs) expressed in terms of the actions. These provide triaxial density profiles with cores or cusps at the centre. They are the first self-consistent triaxial models with analytic DFs suitable for modelling giant ellipticals and dark haloes. Specifically, we study triaxial models that reproduce the Hernquist profile from Williams & Evans, as well as flattened isochrones of the form proposed by Binney. We explore the kinematics and orbital structure of these models in some detail. The models typically become more radially anisotropic on moving outwards, have velocity ellipsoids aligned in Cartesian coordinates in the centre and aligned in spherical polar coordinates in the outer parts. In projection, the ellipticity of the isophotes and the position angle of the major axis of our models generally changes with radius. So, a natural application is to elliptical galaxies that exhibit isophote twisting. As triaxial Stäckel models do not show isophote twists, our DFs are the first to generate mass density distributions that do exhibit this phenomenon, typically with a gradient of ≈10°/effective radius, which is comparable to the data. Triaxiality is a natural consequence of models that are susceptible to the radial orbit instability. We show how a family of spherical models with anisotropy profiles that transition from isotropic at the centre to radially anisotropic becomes unstable when the outer anisotropy is made sufficiently radial. Models with a larger outer anisotropy can be constructed but are found to be triaxial. We argue that the onset of the radial orbit instability can be identified with the transition point when adiabatic relaxation yields strongly triaxial rather than weakly spherical endpoints.

  4. Silicon microfabricated beam expander

    SciTech Connect

    Othman, A. Ibrahim, M. N.; Hamzah, I. H.; Sulaiman, A. A.; Ain, M. F.

    2015-03-30

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

  5. The Consistent Vehicle Routing Problem

    SciTech Connect

    Groer, Christopher S; Golden, Bruce; Edward, Wasil

    2009-01-01

    In the small package shipping industry (as in other industries), companies try to differentiate themselves by providing high levels of customer service. This can be accomplished in several ways, including online tracking of packages, ensuring on-time delivery, and offering residential pickups. Some companies want their drivers to develop relationships with customers on a route and have the same drivers visit the same customers at roughly the same time on each day that the customers need service. These service requirements, together with traditional constraints on vehicle capacity and route length, define a variant of the classical capacitated vehicle routing problem, which we call the consistent VRP (ConVRP). In this paper, we formulate the problem as a mixed-integer program and develop an algorithm to solve the ConVRP that is based on the record-to-record travel algorithm. We compare the performance of our algorithm to the optimal mixed-integer program solutions for a set of small problems and then apply our algorithm to five simulated data sets with 1,000 customers and a real-world data set with more than 3,700 customers. We provide a technique for generating ConVRP benchmark problems from vehicle routing problem instances given in the literature and provide our solutions to these instances. The solutions produced by our algorithm on all problems do a very good job of meeting customer service objectives with routes that have a low total travel time.

  6. Deducing Wild 2 Components with a Statistical Dataset of Olivine in Chondrite Matrix

    NASA Technical Reports Server (NTRS)

    Frank, D. R.; Zolensky, M. E.; Le, L.

    2012-01-01

    , Wild 2 may have received a larger contribution from the Kakangari and/or enstatite chondrite forming regions. Alternatively, Wild 2 may have undergone accretion in an anomalously reducing region, marked by nebular condensation of this atypical forsterite. In [4], a similar conclusion was reached with an Fe-XANES study. We will also use similar lines of reasoning, and our previous conclusions in [5], to constrain the relative contributions of silicates that appear to have been radially transported from different ordinary and carbonaceous chondrite forming regions to the Kuiper Belt. In addition, the widespread depletion of Cr in these FeO-rich (Fa(sub greater than 20)) fragments is consistent with mild thermal metamorphism in Wild 2.

  7. A Refined Zigzag Beam Theory for Composite and Sandwich Beams

    NASA Technical Reports Server (NTRS)

    Tessler, Alexander; Sciuva, Marco Di; Gherlone, Marco

    2009-01-01

    A new refined theory for laminated composite and sandwich beams that contains the kinematics of the Timoshenko Beam Theory as a proper baseline subset is presented. This variationally consistent theory is derived from the virtual work principle and employs a novel piecewise linear zigzag function that provides a more realistic representation of the deformation states of transverse-shear flexible beams than other similar theories. This new zigzag function is unique in that it vanishes at the top and bottom bounding surfaces of a beam. The formulation does not enforce continuity of the transverse shear stress across the beam s cross-section, yet is robust. Two major shortcomings that are inherent in the previous zigzag theories, shear-force inconsistency and difficulties in simulating clamped boundary conditions, and that have greatly limited the utility of these previous theories are discussed in detail. An approach that has successfully resolved these shortcomings is presented herein. Exact solutions for simply supported and cantilevered beams subjected to static loads are derived and the improved modelling capability of the new zigzag beam theory is demonstrated. In particular, extensive results for thick beams with highly heterogeneous material lay-ups are discussed and compared with corresponding results obtained from elasticity solutions, two other zigzag theories, and high-fidelity finite element analyses. Comparisons with the baseline Timoshenko Beam Theory are also presented. The comparisons clearly show the improved accuracy of the new, refined zigzag theory presented herein over similar existing theories. This new theory can be readily extended to plate and shell structures, and should be useful for obtaining relatively low-cost, accurate estimates of structural response needed to design an important class of high-performance aerospace structures.

  8. Beam geometry selection using sequential beam addition

    SciTech Connect

    Popple, Richard A. Brezovich, Ivan A.; Fiveash, John B.

    2014-05-15

    Purpose: The selection of optimal beam geometry has been of interest since the inception of conformal radiotherapy. The authors report on sequential beam addition, a simple beam geometry selection method, for intensity modulated radiation therapy. Methods: The sequential beam addition algorithm (SBA) requires definition of an objective function (score) and a set of candidate beam geometries (pool). In the first iteration, the optimal score is determined for each beam in the pool and the beam with the best score selected. In the next iteration, the optimal score is calculated for each beam remaining in the pool combined with the beam selected in the first iteration, and the best scoring beam is selected. The process is repeated until the desired number of beams is reached. The authors selected three treatment sites, breast, lung, and brain, and determined beam arrangements for up to 11 beams from a pool comprised of 25 equiangular transverse beams. For the brain, arrangements were additionally selected from a pool of 22 noncoplanar beams. Scores were determined for geometries comprised equiangular transverse beams (EQA), as well as two tangential beams for the breast case. Results: In all cases, SBA resulted in scores superior to EQA. The breast case had the strongest dependence on beam geometry, for which only the 7-beam EQA geometry had a score better than the two tangential beams, whereas all SBA geometries with more than two beams were superior. In the lung case, EQA and SBA scores monotonically improved with increasing number of beams; however, SBA required fewer beams to achieve scores equivalent to EQA. For the brain case, SBA with a coplanar pool was equivalent to EQA, while the noncoplanar pool resulted in slightly better scores; however, the dose-volume histograms demonstrated that the differences were not clinically significant. Conclusions: For situations in which beam geometry has a significant effect on the objective function, SBA can identify

  9. Beam impedance of a split cylinder

    SciTech Connect

    Lambertson, G.

    1990-04-01

    A common geometry for position electrodes at moderately low frequencies is the capacitive pickup consisting of a diagonally- divided cylinder that encloses the beam trajectory. For the simplified system here, a relatively direct approach will given the longitudinal and transverse beam impedances (Z{parallel}and Z{perpendicular}) at low frequencies. This paper discusses the determination of this impedance.

  10. Optical beam jitter control

    NASA Astrophysics Data System (ADS)

    Watkins, R. Joseph; Chen, Hong-Jen; Agrawal, Brij N.; Shin, Young S.

    2004-06-01

    For several future imaging and communications spacecraft, a challenging area of technology development is the fine acquisition, tracking, and pointing (ATP) control of the spacecraft and its payload. For example, some spacecraft with large aperture(s) in the range of 10~30 m diameter requires a few arc-seconds accuracy, 10~15 nano-radians jitter, and a fast slewing rate to acquire the target. Furthermore these stringent requirements are at risk of great structure and control interactions. This paper we will focus on the control of optical beam jitter. A Laser Jitter Control (LJC) testbed has been constructed to test jitter algorithms. The testbed consists of two fast steering mirrors (FSM), three position sensing modules (PSM), one diode laser, and several beam splitters and mirrors, all on an isolated Newport optical bench. Jitter is injected with one FSM and the other FSM is used to control it. The jitter spectrum, representing the on-orbit spacecraft and beam jitter environment, contains not only narrow band noise due to rotating devices such as gyroscopes and reaction wheels but also broadband noise. The performance of a Wiener Filter-adaptive algorithm with ideal reference signal is established as the baseline for comparison of adaptive control methods in suppressing both broadband and narrowband disturbances. Specifically, the Least Mean Squares (LMS) approach and the Gradient Adaptive Lattice (GAL) approach are investigated during these experiments.

  11. BEAM CONTAINMENT SYSTEM FOR NSLS-II

    SciTech Connect

    Kramer, S.L.; Casey, W.; Job, P.K.

    2010-05-23

    The shielding design for the NSLS-II will provide adequate protection for the full injected beam loss in two periods of the ring around the injection point, but the remainder of the ring is shielded for lower losses of {le} 10% full beam. This will require a system to insure that beam losses don't exceed these levels for a period of time that could cause excessive radiation levels outside the shield walls. This beam containment system will measure, provide a level of control and alarm indication of the beam power losses along the beam path from the source (e-gun, linac) thru the injection system and the storage ring. This system will consist of collimators that will provide limits to (and potentially to measure) the beam miss-steering and control the loss points of the charge and monitors that will measure the average beam current losses along the beam path and alarm when this beam power loss exceeds the level set by the shielding specifications. This will require some new ideas in beam loss detection capability and collimation. The initial planning and R&D program will be presented.

  12. SAMURAI spectrometer for RI beam experiments

    NASA Astrophysics Data System (ADS)

    Kobayashi, T.; Chiga, N.; Isobe, T.; Kondo, Y.; Kubo, T.; Kusaka, K.; Motobayashi, T.; Nakamura, T.; Ohnishi, J.; Okuno, H.; Otsu, H.; Sako, T.; Sato, H.; Shimizu, Y.; Sekiguchi, K.; Takahashi, K.; Tanaka, R.; Yoneda, K.

    2013-12-01

    A large-acceptance multiparticle spectrometer SAMURAI has been constructed at the RIKEN RI Beam Factory (RIBF) for RI beam experiments. It was designed primarily for kinematically complete experiments such as the invariant-mass spectroscopy of particle-unbound states in exotic nuclei, by detecting heavy fragments and projectile-rapidity nucleons in coincidence. The system consists of a superconducting dipole magnet, beam line detectors, heavy fragment detectors, neutron detectors, and proton detectors. The SAMURAI spectrometer was commissioned in March 2012, and a rigidity resolution of about 1/1500 was obtained for RI beams up to 2.4 GeV/c.

  13. The SSC beam scraper system

    SciTech Connect

    Maslov, M.A.; Mokhov, N.V.; Yazynin Institut Fiziki Vysokikh Ehnergij, Protvino )

    1991-06-01

    In this paper we present the results of a full-scale study of a beam scraping system that is designed to guarantee reliable operation of the SSC throughout the whole cycle and for minimum background for experiments at the interaction regions. The machine aperture limits and beam loss formation are analyzed. Simulation programs and a calculational model are described. The physics of beam scraping is explored, and measures to increase significantly the system efficiency are determined. A tolerable scraping rate, taking into account scraper material integrity, quench limits in downstream superconducting magnets, radiation shielding requirements, and minimal beam halo levels at the IPs are also determined. Finally, a complete multi-component scraper system in the SSC East Cluster is proposed. Throughout the paper we define a scraper as a primary absorber consisting of precise movable jaws that have a flat inner edge along the circulation beam and which may be forced to touch the beam halo in horizontal or vertical planes. Secondary absorbers -- collimators -- are destined to intercept outscattered protons and other particles produced in scraper material. All these are surrounded with a radiation shielding. 15 refs., 50 figs., 13 tabs.

  14. Relativistic electron beam generator

    DOEpatents

    Mooney, L.J.; Hyatt, H.M.

    1975-11-11

    A relativistic electron beam generator for laser media excitation is described. The device employs a diode type relativistic electron beam source having a cathode shape which provides a rectangular output beam with uniform current density.

  15. Laser beam monitoring system

    DOEpatents

    Weil, Bradley S.; Wetherington, Jr., Grady R.

    1985-01-01

    Laser beam monitoring systems include laser-transparent plates set at an angle to the laser beam passing therethrough and light sensor for detecting light reflected from an object on which the laser beam impinges.

  16. Simulation Studies of Beam-Beam Effects of a Ring-Ring Electron-Ion Collider Based on CEBAF

    SciTech Connect

    Yuhong Zhang,Ji Qiang

    2009-05-01

    The collective beam-beam effect can potentially cause a rapid growth of beam sizes and reduce the luminosity of a collider to an unacceptably low level. The ELIC, a proposed ultra high luminosity electron-ion collider based on CEBAF, employs high repetition rate crab crossing colliding beams with very small bunch transverse sizes and very short bunch lengths, and collides them at up to 4 interaction points with strong final focusing. All of these features can make the beam-beam effect challenging. In this paper, we present simulation studies of the beam-beam effect in ELIC using a self-consistent strong-strong beam-beam simulation code developed at Lawrence Berkeley National Laboratory. This simulation study is used for validating the ELIC design and for searching for an optimal parameter set.

  17. Beam imaging sensor

    DOEpatents

    McAninch, Michael D.; Root, Jeffrey J.

    2016-07-05

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

  18. Tunable beam displacer

    SciTech Connect

    Salazar-Serrano, Luis José; Valencia, Alejandra; Torres, Juan P.

    2015-03-15

    We report the implementation of a tunable beam displacer, composed of a polarizing beam splitter (PBS) and two mirrors, that divides an initially polarized beam into two parallel beams whose separation can be continuously tuned. The two output beams are linearly polarized with either vertical or horizontal polarization and no optical path difference is introduced between them. The wavelength dependence of the device as well as the maximum separation between the beams achievable is limited mainly by the PBS characteristics.

  19. BEAM INSTRUMENTATION FOR HIGH POWER HADRON BEAMS

    SciTech Connect

    Aleksandrov, Alexander V

    2013-01-01

    This presentation will describe developments in the beam diagnostics which support the understanding and operation of high power hadron accelerators. These include the measurement of large dynamic range transverse and longitudinal beam profiles, beam loss detection, and non-interceptive diagnostics.

  20. Propagation-invariant beams with quantum pendulum spectra: from Bessel beams to Gaussian beam-beams.

    PubMed

    Dennis, Mark R; Ring, James D

    2013-09-01

    We describe a new class of propagation-invariant light beams with Fourier transform given by an eigenfunction of the quantum mechanical pendulum. These beams, whose spectra (restricted to a circle) are doubly periodic Mathieu functions in azimuth, depend on a field strength parameter. When the parameter is zero, pendulum beams are Bessel beams, and as the parameter approaches infinity, they resemble transversely propagating one-dimensional Gaussian wave packets (Gaussian beam-beams). Pendulum beams are the eigenfunctions of an operator that interpolates between the squared angular momentum operator and the linear momentum operator. The analysis reveals connections with Mathieu beams, and insight into the paraxial approximation.

  1. Method and apparatus for timing of laser beams in a multiple laser beam fusion system

    DOEpatents

    Eastman, Jay M.; Miller, Theodore L.

    1981-01-01

    The optical path lengths of a plurality of comparison laser beams directed to impinge upon a common target from different directions are compared to that of a master laser beam by using an optical heterodyne interferometric detection technique. The technique consists of frequency shifting the master laser beam and combining the master beam with a first one of the comparison laser beams to produce a time-varying heterodyne interference pattern which is detected by a photo-detector to produce an AC electrical signal indicative of the difference in the optical path lengths of the two beams which were combined. The optical path length of this first comparison laser beam is adjusted to compensate for the detected difference in the optical path lengths of the two beams. The optical path lengths of all of the comparison laser beams are made equal to the optical path length of the master laser beam by repeating the optical path length adjustment process for each of the comparison laser beams. In this manner, the comparison laser beams are synchronized or timed to arrive at the target within .+-.1.times.10.sup.-12 second of each other.

  2. Beam instabilities in hadron synchrotrons

    DOE PAGES

    Metral, E.; T. Argyropoulos; Bartosik, H.; ...

    2016-04-01

    Beam instabilities cover a wide range of effects in particle accelerators and they have been the subjects of intense research for several decades. As the machines performance was pushed new mechanisms were revealed and nowadays the challenge consists in studying the interplays between all these intricate phenomena, as it is very often not possible to treat the different effects separately. Furthermore, the aim of this paper is to review the main mechanisms, discussing in particular the recent developments of beam instability theories and simulations.

  3. Shimmed electron beam welding process

    DOEpatents

    Feng, Ganjiang; Nowak, Daniel Anthony; Murphy, John Thomas

    2002-01-01

    A modified electron beam welding process effects welding of joints between superalloy materials by inserting a weldable shim in the joint and heating the superalloy materials with an electron beam. The process insures a full penetration of joints with a consistent percentage of filler material and thereby improves fatigue life of the joint by three to four times as compared with the prior art. The process also allows variable shim thickness and joint fit-up gaps to provide increased flexibility for manufacturing when joining complex airfoil structures and the like.

  4. On the differentiation of N2 components in an appetitive choice task: evidence for the revised Reinforcement Sensitivity Theory.

    PubMed

    Leue, Anja; Chavanon, Mira-Lynn; Wacker, Jan; Stemmler, Gerhard

    2009-11-01

    Task- and personality-related modulations of the N2 were probed within the framework of the revised Reinforcement Sensitivity Theory (RST). Using an appetitive choice task, we investigated 58 students with extreme scores on the behavioral inhibition system and behavioral approach system (BIS/BAS) scales. The baseline-to-peak N2 amplitude was sensitive to the strength of decision conflict and demonstrated RST-related personality differences. In addition to the baseline N2 amplitude, temporal PCA results suggested two N2 components accounting for a laterality effect and capturing different N2 patterns for BIS/BAS groups with increasing conflict level. Evidence for RST-related personality differences was obtained for baseline-to-peak N2 and tPCA components in the present task. The results support the RST prediction that BAS sensitivity modulates conflict processing and confirm the cognitive-motivational conflict concept of RST.

  5. Beam-beam dynamics during the injection process at the PEP-II B-Factory

    SciTech Connect

    Chin, Yong Ho

    1991-10-01

    This paper is concerned with beam-beam effects during the injection process at the proposed asymmetric SLAC/LBL/LLNL B-Factory based on PEP (PEP-2). For symmetric colliders, the primary source of the beam-beam effect is the head-on collision at the interaction point (IP), and this effect can be mitigated by separating the beams during the injection process. For an asymmetric collider, which intrinsically consists of two separate rings, the bunches not only collide at the IP but experience a long-range beam-beam force on the way into and out of the IP region. These collisions are called ``parasitic crossings (PC).`` The parasitic crossings emerge as a potential source of far stronger beam-beam impact during the injection process for the following reason. In the proposed injection scheme of the APIARY-6.3d design, the bunches are injected horizontally into the two rings with large horizontal offset of 8{sigma}{sub Ox}{sup sptm} where {sigma}{sub Ox}{sup sptm} is the nominal horizontal storage ring beam size at the end of the septum magnet. Then, the injected beam starts to travel around the ring oscillating horizontally. For the sake of discussion, let us assume that the beam in the other ring has already been fully stored. When the injected beam arrives at the 1st PC, where the two nominal orbits are separated horizontally by about 7.6 times the nominal horizontal beam size of the low energy ring, it may pass through the other beam far more closely than at the nominal separation distance, or it may even strike the other beam head-on.

  6. Beam-beam dynamics during the injection process at the PEP-II B-Factory

    SciTech Connect

    Chin, Yong Ho.

    1991-10-01

    This paper is concerned with beam-beam effects during the injection process at the proposed asymmetric SLAC/LBL/LLNL B-Factory based on PEP (PEP-2). For symmetric colliders, the primary source of the beam-beam effect is the head-on collision at the interaction point (IP), and this effect can be mitigated by separating the beams during the injection process. For an asymmetric collider, which intrinsically consists of two separate rings, the bunches not only collide at the IP but experience a long-range beam-beam force on the way into and out of the IP region. These collisions are called parasitic crossings (PC).'' The parasitic crossings emerge as a potential source of far stronger beam-beam impact during the injection process for the following reason. In the proposed injection scheme of the APIARY-6.3d design, the bunches are injected horizontally into the two rings with large horizontal offset of 8{sigma}{sub Ox}{sup sptm} where {sigma}{sub Ox}{sup sptm} is the nominal horizontal storage ring beam size at the end of the septum magnet. Then, the injected beam starts to travel around the ring oscillating horizontally. For the sake of discussion, let us assume that the beam in the other ring has already been fully stored. When the injected beam arrives at the 1st PC, where the two nominal orbits are separated horizontally by about 7.6 times the nominal horizontal beam size of the low energy ring, it may pass through the other beam far more closely than at the nominal separation distance, or it may even strike the other beam head-on.

  7. A 2-component system is involved in the early stages of the Pisolithus tinctorius-Pinus greggii symbiosis.

    PubMed

    Herrera-Martínez, Aseneth; Ruiz-Medrano, Roberto; Galván-Gordillo, Santiago Valentín; Toscano Morales, Roberto; Gómez-Silva, Lidia; Valdés, María; Hinojosa-Moya, Jesús; Xoconostle-Cázares, Beatriz

    2014-01-01

    Ectomycorrhizal symbiosis results in profound morphological and physiological modifications in both plant and fungus. This in turn is the product of differential gene expression in both co-symbionts, giving rise to specialized cell types capable of performing novel functions. During the precolonization stage, chemical signals from root exudates are sensed by the ectomycorrizal fungus, and vice versa, which are in principle responsible for the observed change in the developmental symbionts program. Little is known about the molecular mechanisms involved in the signaling and recognition between ectomycorrhizal fungi and their host plants. In the present work, we characterized a novel lactone, termed pinelactone, and identified a gene encoding for a histidine kinase in Pisolithus tictorius, which function is proposed to be the perception of the aforementioned metabolites. In this study, the use of closantel, a specific inhibitor of histidine kinase phosphorylation, affected the capacity for fungal colonization in the symbiosis between Pisolithus tinctorius and Pinus greggii, indicating that a 2-component system (TCS) may operate in the early events of plant-fungus interaction. Indeed, the metabolites induced the accumulation of Pisolithus tinctorius mRNA for a putative histidine kinase (termed Pthik1). Of note, Pthik1 was able to partially complement a S. cerevisiae histidine kinase mutant, demonstrating its role in the response to the presence of the aforementioned metabolites. Our results indicate a role of a 2-component pathway in the early stages of ectomycorrhizal symbiosis before colonization. Furthermore, a novel lactone from Pinus greggii root exudates may activate a signal transduction pathway that contributes to the establishment of the ectomycorrhizal symbiosis.

  8. Antenna Beam Coverage Concepts

    NASA Technical Reports Server (NTRS)

    Estabrook, Polly; Motamedi, Masoud

    1990-01-01

    The strawman Personal Access Satellite System (PASS) design calls for the use of a CONUS beam for transmission between the supplier and the satellite and for fixed beams for transmission between the basic personal terminal and the satellite. The satellite uses a 3 m main reflector for transmission at 20 GHz and a 2 m main reflector for reception at 30 GHz. There are several types of spot beams under consideration for the PASS system besides fixed beams. The beam pattern of a CONUS coverage switched beam is shown along with that of a scanning beam. A switched beam refers to one in which the signal from the satellite is connected alternatively to various feed horns. Scanning beams are taken to mean beams whose footprints are moved between contiguous regions in the beam's coverage area. The advantages and disadvantages of switched and/or scanning beams relative to fixed beams. The consequences of using switched/scanning in lieu of fixed beams in the PASS design and attempts are made to evaluate the listed advantages and disadvantages. Two uses of switched/scanning beams are examined. To illustrate the implications of switched beams use on PASS system design, operation at two beam scan rates is explored.

  9. Telecommunication using muon beams

    DOEpatents

    Arnold, Richard C.

    1976-01-01

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

  10. Elliptical Laguerre-Gaussian correlated Schell-model beam.

    PubMed

    Chen, Yahong; Liu, Lin; Wang, Fei; Zhao, Chengliang; Cai, Yangjian

    2014-06-02

    A new kind of partially coherent beam with non-conventional correlation function named elliptical Laguerre-Gaussian correlated Schell-model (LGCSM) beam is introduced. Analytical propagation formula for an elliptical LGCSM beam passing through a stigmatic ABCD optical system is derived. The elliptical LGCSM beam exhibits unique features on propagation, e.g., its intensity in the far field (or in the focal plane) displays an elliptical ring-shaped beam profile, being qualitatively different from the circular ring-shaped beam profile of the circular LGCSM beam. Furthermore, we carry out experimental generation of an elliptical LGCSM beam with controllable ellipticity, and measure its focusing properties. Our experimental results are consistent with the theoretical predictions. The elliptical LGCSM beam will be useful in atomic optics.

  11. LANSCE beam current limiter

    SciTech Connect

    Gallegos, F.R.

    1996-06-01

    The Radiation Security System (RSS) at the Los Alamos Neutron Science Center (LANSCE) provides personnel protection from prompt radiation due to accelerated beam. Active instrumentation, such as the Beam Current Limiter, is a component of the RSS. The current limiter is designed to limit the average current in a beam line below a specific level, thus minimizing the maximum current available for a beam spill accident. The beam current limiter is a self-contained, electrically isolated toroidal beam transformer which continuously monitors beam current. It is designed as fail-safe instrumentation. The design philosophy, hardware design, operation, and limitations of the device are described.

  12. SUMMARY OF BEAM BEAM OBSERVATIONS DURING STORES IN RHIC.

    SciTech Connect

    FISCHER,W.

    2003-05-19

    During stores, the beam-beam interaction has a significant impact on the beam and luminosity lifetimes in RHIC. This was observed in heavy ion, and even more pronounced in proton collisions. Observations include measurements of beam-beam induced tune shifts, lifetime and emittance growth measurements with and without beam-beam interaction, and background rates as a function of tunes. In addition, RHIC is currently the only hadron collider in which strong-strong beam-beam effects can be seen. Coherent beam-beam modes were observed, and suppressed by tune changes. In this article we summarize the most important beam-beam observations made during stores so far.

  13. Partially coherent nonparaxial beams.

    PubMed

    Duan, Kailiang; Lü, Baida

    2004-04-15

    The concept of a partially coherent nonparaxial beam is proposed. A closed-form expression for the propagation of nonparaxial Gaussian Schell model (GSM) beams in free space is derived and applied to study the propagation properties of nonparaxial GSM beams. It is shown that for partially coherent nonparaxial beams a new parameter f(sigma) has to be introduced, which together with the parameter f, determines the beam nonparaxiality.

  14. Automated beam builder

    NASA Technical Reports Server (NTRS)

    Muench, W. K.

    1980-01-01

    Requirements for the space fabrication of large space structures are considered with emphasis on the design, development, manufacture, and testing of a machine which automatically produces a basic building block aluminum beam. Particular problems discussed include those associated with beam cap forming; brace storage, dispensing, and transporting; beam component fastening; and beam cut-off. Various critical process tests conducted to develop technology for a machine to produce composite beams are also discussed.

  15. Optical Beam-Shear Sensors

    NASA Technical Reports Server (NTRS)

    Martin, Stefan; Szwaykowski, Piotr

    2007-01-01

    A technique for measuring optical beam shear is based on collecting light from the four quadrants of the beam and comparing the optical power collected from each quadrant with that from the other three quadrants. As used here, "shear" signifies lateral displacement of a beam of light from a nominal optical axis. A sensor for implementing this technique consists of a modified focusing lens and a quad-cell photodetector, both centered on the nominal optical axis. The modification of the lens consists in cutting the lens into four sectors (corresponding to the four quadrants) by sawing along two orthogonal diameters, then reassembling the lens following either of two approaches described next. In one approach, the lens is reassembled by gluing the sectors back together. In the simplest variant of this approach, the kerf of the saw matches the spacing of the photodetector cells, so that the focus of each sector crosses the axis of symmetry to fall on the opposite photodetector cell (see figure). In another variant of this approach, the lens sectors are spaced apart to make their individual foci to fall on separate photodetector cells, without crossing the optical axis. In the case of a sufficiently wide beam, the modified lens could be replaced with four independent lenses placed in a square array, each focusing onto an independent photodetector

  16. Optical routing system consisting of spatial light modulator and kinoform phase gratings

    NASA Astrophysics Data System (ADS)

    Lee, Deug Ju; Kim, Nam; Song, Seok Ho; Suh, HoHyung

    1996-05-01

    Dynamic free-space optical routing system is experimented by a holographic crossbar with single-stage switching architecture. For dynamic operation, electrically addressed liquid- crystal spatial light modulator and diffraction gratings are used in place of passive holograms. Diffraction gratings are consisted of regular cells and have multiple phase delays. This pixelated kinoform phase grating array displayed on SLM deflects a input beam toward a wanted direction or splits a input beam into many beams and then steers them to desired positions. Each grating array is combined with three periods of grating which is constructed by 32 X 32 pixels with equally space phase levels. This system has higher efficiencies and superior characteristics of beam split, and produces asymmetric output beam pattern. In this system, input ports are 3 X 3 and output ports are 5 X 5. It operates at high speed as dynamic free-space optical switch and leads low optical losses.

  17. Fermilab HINS Proton Ion Source Beam Measurements

    SciTech Connect

    Tam, W.M.; Apollinari, G.; Chaurize, S.; Hays, S.; Romanov, G.; Scarpine, V.; Schmidt, C.; Webber, R.; /Fermilab

    2009-05-01

    The proton ion source for the High Intensity Neutrino Source (HINS) Linac front-end at Fermilab has been successfully commissioned. It produces a 50 keV, 3 msec beam pulse with a peak current greater than 20mA at 2.5Hz. The beam is transported to the radio-frequency quadrupole (RFQ) by a low energy beam transport (LEBT) that consists of two focusing solenoids, four steering dipole magnets and a beam current transformer. To understand beam transmission through the RFQ, it is important to characterize the 50 keV beam before connecting the LEBT to the RFQ. A wire scanner and a Faraday cup are temporarily installed at the exit of the LEBT to study the beam parameters. Beam profile measurements are made for different LEBT settings and results are compared to those from computer simulations. In lieu of direct emittance measurements, solenoid variation method based on profile measurements is used to reconstruct the beam emittance.

  18. Electron beam injection experiments - Replication of flight observations in a laboratory beam plasma discharge

    NASA Technical Reports Server (NTRS)

    Bernstein, W.; Mcgarity, J. O.; Konradi, A.

    1983-01-01

    Recent electron beam injection experiments in the lower ionosphere have produced two perplexing results: (1) At altitudes from 140 km to 220 km, the beam associated 391.4 nm intensity is relatively independent of altitude despite the decreasing N2 abundance. (2) The radial extent of the perturbed region populated by beam associated energetic electrons significantly exceeds the nominal gyrodiameter for 90 deg injection. A series of laboratory measurements is described in which both of these flight results appear to have been closely reproduced. The laboratory results are reasonably consistent with the transition from a collision dominated to collisionless beam-plasma discharge configuration.

  19. Tevatron beam-beam compensation project progress

    SciTech Connect

    Shiltsev, V.; Zhang, X.L.; Kuznetsov, G.; Pfeffer, H.; Saewert, G.; Zimmermann, F.; Tiunov, M.; Bishofberger, K.; Bogdanov, I.; Kashtanov, E.; Kozub, S.; Sytnik, V.; Tkachenko, L.; /Serpukhov, IHEP

    2005-05-01

    In this paper, we report the progress of the Tevatron Beam-Beam Compensation (BBC) project [1]. Electron beam induced proton and antiproton tuneshifts have been reported in [2], suppression of an antiproton emittance growth has been observed, too [1]. Currently, the first electron lens (TEL1) is in operational use as the Tevatron DC beam cleaner. We have made a lot of the upgrades to improve its stability [3]. The 2nd Tevatron electron lens (TEL2) is under the final phase of development and preparation for installation in the Tevatron.

  20. RHIC electron lens beam transport system design considerations

    SciTech Connect

    Gu, X.; Pikin, A.; Okamura, M.; Fischer, W.; Luo, Y.; Gupta, R.; Hock, J.; Jain, A.; Raparia, D.

    2010-10-01

    To apply head-on beam-beam compensation for RHIC, two electron lenses are designed and will be installed at IP10. Electron beam transport system is one of important subsystem, which is used to transport electron beam from electron gun side to collector side. This system should be able to change beam size inside superconducting magnet and control beam position with 5 mm in horizontal and vertical plane. Some other design considerations for this beam transport system are also reported in this paper. The head-on beam-beam effect is one of important nonlinear source in storage ring and linear colliders, which have limited the luminosity improvement of many colliders, such as SppS, Tevatron and RHIC. In order to enhance the performance of colliders, beam-beam effects can be compensated with direct space charge compensation, indirect space charge compensation or betatron phase cancellation scheme. Like other colliders, indirect space charge compensation scheme (Electron Lens) was also proposed for Relativistic Heavy Ion Collider (RHIC) beam-beam compensation at Brookhaven National Laboratory. The two similar electron lenses are located in IR10 between the DX magnets. One RHIC electron lens consists of one DC electron gun, one superconducting magnet, one electron collector and beam transport system.

  1. Simulation of periodically focused, adiabatic thermal beams

    SciTech Connect

    Chen, C.; Akylas, T. R.; Barton, T. J.; Field, D. M.; Lang, K. M.; Mok, R. V.

    2012-12-21

    Self-consistent particle-in-cell simulations are performed to verify earlier theoretical predictions of adiabatic thermal beams in a periodic solenoidal magnetic focusing field [K.R. Samokhvalova, J. Zhou and C. Chen, Phys. Plasma 14, 103102 (2007); J. Zhou, K.R. Samokhvalova and C. Chen, Phys. Plasma 15, 023102 (2008)]. In particular, results are obtained for adiabatic thermal beams that do not rotate in the Larmor frame. For such beams, the theoretical predictions of the rms beam envelope, the conservations of the rms thermal emittances, the adiabatic equation of state, and the Debye length are verified in the simulations. Furthermore, the adiabatic thermal beam is found be stable in the parameter regime where the simulations are performed.

  2. Update on POCIT portable optical communicators: VideoBeam and EtherBeam

    NASA Astrophysics Data System (ADS)

    Mecherle, G. Stephen; Holcomb, Terry L.

    2000-05-01

    LDSC is developing the POCITTM (Portable Optical Communication Integrated Transceiver) family of products which includes VideoBeamTM and the latest addition, EtherBeamTM. Each is a full duplex portable laser communicator: VideoBeamTM providing near-broadcast- quality analog video and stereo audio, and EtherBeamTM providing standard Ethernet connectivity. Each POCITTM transceiver consists of a 3.5-pound unit with a binocular- type form factor, which can be manually pointed, tripod- mounted or gyro-stabilized. Both units have an operational range of over two miles (clear air) with excellent jam- resistance and low probability of interception characteristics. The transmission wavelength of 1550 nm enables Class 1 eyesafe operation (ANSI, IEC). The POCITTM units are ideally suited for numerous military scenarios, surveillance/espionage, industrial precious mineral exploration, and campus video teleconferencing applications. VideoBeam will be available second quarter 2000, followed by EtherBeam in third quarter 2000.

  3. Beam position monitor

    DOEpatents

    Alkire, Randy W.; Rosenbaum, Gerold; Evans, Gwyndaf

    2003-07-22

    An apparatus for determining the position of an x-ray beam relative to a desired beam axis. Where the apparatus is positioned along the beam path so that a thin metal foil target intersects the x-ray beam generating fluorescent radiation. A PIN diode array is positioned so that a portion of the fluorescent radiation is intercepted by the array resulting in an a series of electrical signals from the PIN diodes making up the array. The signals are then analyzed and the position of the x-ray beam is determined relative to the desired beam path.

  4. LANSCE beam current limiter

    SciTech Connect

    Gallegos, F.R.

    1997-01-01

    The Radiation Security System (RSS) at the Los Alamos Neutron Science Center (LANSCE) provides personnel protection from prompt radiation due to accelerated beam. Active instrumentation, such as the beam current limiter, is a component of the RSS. The current limiter is designed to limit the average current in a beamline below a specific level, thus minimizing the maximum current available for a beam spill accident. The beam current limiter is a self-contained, electrically isolated toroidal beam transformer which continuously monitors beam current. It is designed as fail-safe instrumentation. The design philosophy, hardware design, operation, and limitations of the device are described. {copyright} {ital 1997 American Institute of Physics.}

  5. Beam position monitor

    SciTech Connect

    Alkire, Randy W.; Rosenbaum, Gerold; Evans, Gwyndaf

    2000-09-21

    An apparatus for determining the position of an x-ray beam relative to a desired beam axis where the apparatus is positioned along the beam path so that a thin metal foil target intersects the x-ray beam generating fluorescent radiation. A PIN diode array is positioned so that a portion of the fluorescent radiation is intercepted by the array resulting in a series of electrical signals from the PIN diodes making up the array. The signals are then analyzed and the position of the x-ray beam is determined relative to the desired beam path.

  6. Pyramid beam splitter

    DOEpatents

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

    1992-01-01

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

  7. 40 CFR 55.12 - Consistency updates.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 5 2010-07-01 2010-07-01 false Consistency updates. 55.12 Section 55...) OUTER CONTINENTAL SHELF AIR REGULATIONS § 55.12 Consistency updates. (a) The Administrator will update... to update part 55 accordingly. (c) Consistency reviews triggered by receipt of an NOI. Upon...

  8. Hollow structure formation of intense ion beams with sharp edge in background plasmas

    SciTech Connect

    Hu, Zhang-Hu; Wang, You-Nian

    2016-02-15

    The transport of intense ion beams with sharp radial beam edge in plasmas has been studied with two-dimensional electromagnetic particle simulations. The initial solid beam evolves into a hollow beam due to the nonlinear sharp transverse force peak in the regions of beam edge. The magnitude and nonlinearity of this peak are enhanced as the ion beam travels further into the plasma, due to the self-consistent interactions between the beam ions and the plasma electrons. This structure formation is shown to be independent on the beam radius.

  9. Piezoelectric performance of continuous beam and narrow supported beam arrays for artificial basilar membranes

    NASA Astrophysics Data System (ADS)

    Song, Won Joon; Jang, Jongmoon; Kim, Sangwon; Choi, Hongsoo

    2014-09-01

    We report an experimental assessment of the electrical performance of two piezoelectric beam arrays for artificial basilar membranes (ABMs): a continuous beam array (CBA) and a narrow-supports beam array (NSBA). Both arrays consist of piezoelectric beams of sequentially varying lengths that mimic the frequency selectivity of mammalian cochleae. The narrow supports of the NSBA resulted in lateral deformation of the beams, whereas the CBA beams were flat. The displacement and piezoelectric output of each beam were measured at the resonance frequency of each beam using a scanning laser-Doppler vibrometer (SLDV). Both ABM prototypes showed mechanical frequency selectivity that depended on the beam length. The CBA generated a piezoelectric output in the range 6.6-23.2 μV and exhibited electrical frequency separability, whereas the NSBA failed to generate sufficient electrical potential due to the lateral deformation of the piezoelectric beams. The CBA was found to be more effective as an ABM, with potential for use in cochlear implants.

  10. Beam-beam issues in asymmetric colliders

    SciTech Connect

    Furman, M.A.

    1992-07-01

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

  11. Solar wind double ions beams and the heliospheric current sheet

    NASA Technical Reports Server (NTRS)

    Hammond, C. M.; Feldman, W. C.; Phillips, J. L.; Goldstein, B. E.; Balogh, A.

    1995-01-01

    Double ion beams are often observed in the solar wind, but little work has been done in relating these beams to structures within the solar wind. Double ion beams are observed as beams of a given ion species and charge state occurring at two different energies. We use the three-dimensional ion plasma instrument on board the Ulysses spacecraft to look for evidence of such beams associated with the heliospheric current sheet. In a subset chosen independently of plasma parameters consisting of 8 of cover 47 crossings of the current sheet made during the inecliptic phase of the Ulysses mission we find that these double ion beams are always present on either side of the current sheet. The double beams are present in both the proton and helium species. The secondary beam typically has a higher helium abundance, which suggests that these beams are formed in the helium-rich corona rather than in interplanetary space. The double beams are not present in the interior of the current sheet. Neither collisions nor effects of plasma beta can account for the disappearance of the double beams inside the current sheet in all eight cases. We postulate that these beams are formed by reconnection occurring near the Sun in the boundary region between the open field lines of the coronal holes and the closed field line region of the heliospheric current sheet. Such a scenario would be consistent with previous X ray measurements which suggect that reconnection is occurring in this region.

  12. BEAMS3D Neutral Beam Injection Model

    SciTech Connect

    Lazerson, Samuel

    2014-04-14

    With the advent of applied 3D fi elds in Tokamaks and modern high performance stellarators, a need has arisen to address non-axisymmetric effects on neutral beam heating and fueling. We report on the development of a fully 3D neutral beam injection (NBI) model, BEAMS3D, which addresses this need by coupling 3D equilibria to a guiding center code capable of modeling neutral and charged particle trajectories across the separatrix and into the plasma core. Ionization, neutralization, charge-exchange, viscous velocity reduction, and pitch angle scattering are modeled with the ADAS atomic physics database [1]. Benchmark calculations are presented to validate the collisionless particle orbits, neutral beam injection model, frictional drag, and pitch angle scattering effects. A calculation of neutral beam heating in the NCSX device is performed, highlighting the capability of the code to handle 3D magnetic fields.

  13. Successful Beam-Beam Tuneshift Compensation

    SciTech Connect

    Bishofberger, Kip Aaron

    2005-01-01

    The performance of synchrotron colliders has been limited by the beam-beam limit, a maximum tuneshift that colliding bunches could sustain. Due to bunch-to-bunch tune variation and intra-bunch tune spread, larger tuneshifts produce severe emittance growth. Breaking through this constraint has been viewed as impossible for several decades. This dissertation introduces the physics of ultra-relativistic synchrotrons and low-energy electron beams, with emphasis placed on the limits of the Tevatron and the needs of a tuneshift-compensation device. A detailed analysis of the Tevatron Electron Lens (TEL) is given, comparing theoretical models to experimental data whenever possible. Finally, results of Tevatron operations with inclusion of the TEL are presented and analyzed. It is shown that the TEL provides a way to shatter the previously inescapable beam-beam limit.

  14. Laser beam complex amplitude measurement by phase diversity.

    PubMed

    Védrenne, Nicolas; Mugnier, Laurent M; Michau, Vincent; Velluet, Marie-Thérèse; Bierent, Rudolph

    2014-02-24

    The control of the optical quality of a laser beam requires a complex amplitude measurement able to deal with strong modulus variations and potentially highly perturbed wavefronts. The method proposed here consists in an extension of phase diversity to complex amplitude measurements that is effective for highly perturbed beams. Named camelot for Complex Amplitude MEasurement by a Likelihood Optimization Tool, it relies on the acquisition and processing of few images of the beam section taken along the optical path. The complex amplitude of the beam is retrieved from the images by the minimization of a Maximum a Posteriori error metric between the images and a model of the beam propagation. The analytical formalism of the method and its experimental validation are presented. The modulus of the beam is compared to a measurement of the beam profile, the phase of the beam is compared to a conventional phase diversity estimate. The precision of the experimental measurements is investigated by numerical simulations.

  15. Electron beam directed energy device and methods of using same

    DOEpatents

    Retsky, Michael W.

    2007-10-16

    A method and apparatus is disclosed for an electron beam directed energy device. The device consists of an electron gun with one or more electron beams. The device includes one or more accelerating plates with holes aligned for beam passage. The plates may be flat or preferably shaped to direct each electron beam to exit the electron gun at a predetermined orientation. In one preferred application, the device is located in outer space with individual beams that are directed to focus at a distant target to be used to impact and destroy missiles. The aimings of the separate beams are designed to overcome Coulomb repulsion. A method is also presented for directing the beams to a target considering the variable terrestrial magnetic field. In another preferred application, the electron beam is directed into the ground to produce a subsurface x-ray source to locate and/or destroy buried or otherwise hidden objects including explosive devices.

  16. Beam transport and bunch compression at TARLA

    NASA Astrophysics Data System (ADS)

    Aksoy, Avni; Lehnert, Ulf

    2014-10-01

    The Turkish Accelerator and Radiation Laboratory in Ankara (TARLA) will operate two InfraRed Free Electron Lasers (IR-FEL) covering the range of 3-250 μm. The facility will consist of an injector fed by a thermionic triode gun with two-stage RF bunch compression, two superconducting accelerating ELBE modules operating at continuous wave (CW) mode and two independent optical resonator systems with different undulator period lengths. The electron beam will also be used to generate Bremsstrahlung radiation. In this study, we present the electron beam transport including beam matching to the undulators and the shaping of the longitudinal phase space using magnetic dispersive sections.

  17. Design for controllable optofluidic beam splitter

    NASA Astrophysics Data System (ADS)

    Tang, Xionggui; Liang, Shan; Li, Rujian

    2016-01-01

    A novel configuration for controllable optofluidic beam splitter is proposed, which consists of the asymmetric Y-branch waveguide and the microfluidic channel filled with fluid mixture. The beam propagation method (BPM) is employed to numerically investigate the optical performance of device in our layout. The simulated results demonstrate that arbitrary splitting ratio and low optical loss for both TE and TM mode can be easily achieved, with a low dependence of wavelength and polarization. Particularly, the optofluidic beam splitter has advantages such as compact structure and large fabrication tolerance. The proposed device provides a new way to manipulate the optical power splitting, and has wide potential applications in integrated optofluidic system.

  18. Electron Beam Freeform Fabrication

    NASA Video Gallery

    Electron Beam Freeform Fabrication (EBF3) is a process by which NASA hopes to build metal parts in zero gravity environments. It's a layer-additive process that uses an electron beam and a solid wi...

  19. High energy beam lines

    NASA Astrophysics Data System (ADS)

    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.

  20. Low energy beam transport system developments

    SciTech Connect

    Dudnikov, V.; Han, B.; Stockli, M.; Welton, R.; Dudnikova, G.

    2015-04-08

    For high brightness beam production it is important to preserve the brightness in the low energy beam transport system (LEBT) used to transport and match the ion beams to the next stage of acceleration, usually an RFQ. While electrostatic focusing can be problematic for high current beam transport, reliable electrostatic LEBT operation has been demonstrated with H{sup −} beams up to 60 mA. Now, however, it is commonly accepted that an optimal LEBT for high current accelerator applications consists of focusing solenoids with space charge compensation. Two-solenoid LEBTs are successfully used for high current (>100 mA) proton beam transport. Preservation of low emittances (~0.15 π mm-mrad) requires the addition of a heavy gas (Xe, Kr), which causes ~5% of proton loss in a 1 m long LEBT. Similar Xe densities would be required to preserve low emittances of H{sup −} beams, but such gas densities cause unacceptably high H{sup −} beam losses. A short LEBT with only one short solenoid, movable for RFQ matching, can be used for reduced negative ion stripping. A strong electrostatic-focusing LEBT has been successfully adopted for transport of high current H{sup −} beams in the SNS Front End. Some modifications of such electrostatic LEBTs are expected to improve the reliable transport of intense positive and negative ion beams without greatly degrading their low emittances. We concentrate on processes that determine the beam brightness degradation and on their prevention. Proposed improvements to the SNS electrostatic LEBT are discussed.

  1. Electron beam focusing system

    SciTech Connect

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

    1997-09-01

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

  2. PARTICLE BEAM TRACKING CIRCUIT

    DOEpatents

    Anderson, O.A.

    1959-05-01

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

  3. Beam Dynamics for ARIA

    SciTech Connect

    Ekdahl, Carl August Jr.

    2014-10-14

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

  4. Beam characterization at the Neutron Radiography Reactor

    SciTech Connect

    Sarah W. Morgan; Jeffrey C. King; Chad L. Pope

    2013-12-01

    The quality of a neutron-imaging beam directly impacts the quality of radiographic images produced using that beam. Fully characterizing a neutron beam, including determination of the beam's effective length-to-diameter ratio, neutron flux profile, energy spectrum, potential image quality, and beam divergence, is vital for producing quality radiographic images. This paper provides a characterization of the east neutron imaging beamline at the Idaho National Laboratory Neutron Radiography Reactor (NRAD). The experiments which measured the beam's effective length-to-diameter ratio and potential image quality are based on American Society for Testing and Materials (ASTM) standards. An analysis of the image produced by a calibrated phantom measured the beam divergence. The energy spectrum measurements consist of a series of foil irradiations using a selection of activation foils, compared to the results produced by a Monte Carlo n-Particle (MCNP) model of the beamline. The NRAD has an effective collimation ratio greater than 125, a beam divergence of 0.3 +_ 0.1 degrees, and a gold foil cadmium ratio of 2.7. The flux profile has been quantified and the facility is an ASTM Category 1 radiographic facility. Based on bare and cadmium covered foil activation results, the neutron energy spectrum used in the current MCNP model of the radiography beamline over-samples the thermal region of the neutron energy spectrum.

  5. Intense non-relativistic cesium ion beam

    SciTech Connect

    Lampel, M.C.

    1984-02-01

    The Heavy Ion Fusion group at Lawrence Berkeley Laboratory has constructed the One Ampere Cesium Injector as a proof of principle source to supply an induction linac with a high charge density and high brightness ion beam. This is studied here. An electron beam probe was developed as the major diagnostic tool for characterizing ion beam space charge. Electron beam probe data inversion is accomplished with the EBEAM code and a parametrically adjusted model radial charge distribution. The longitudinal charge distribution was not derived, although it is possible to do so. The radial charge distribution that is derived reveals an unexpected halo of trapped electrons surrounding the ion beam. A charge fluid theory of the effect of finite electron temperature on the focusing of neutralized ion beams (Nucl. Fus. 21, 529 (1981)) is applied to the problem of the Cesium beam final focus at the end of the injector. It is shown that the theory's predictions and assumptions are consistent with the experimental data, and that it accounts for the observed ion beam radius of approx. 5 cm, and the electron halo, including the determination of an electron Debye length of approx. 10 cm.

  6. Low energy ion beam dynamics of NANOGAN ECR ion source

    NASA Astrophysics Data System (ADS)

    Kumar, Sarvesh; Mandal, A.

    2016-04-01

    A new low energy ion beam facility (LEIBF) has been developed for providing the mass analyzed highly charged intense ion beams of energy ranging from a few tens of keV to a few MeV for atomic, molecular and materials sciences research. The new facility consists of an all permanent magnet 10 GHz electron cyclotron resonance (ECR) ion source (NANOGAN) installed on a high voltage platform (400 kV) which provides large currents of multiply charged ion beams. Higher emittance at low energy of intense ion beam puts a tremendous challenge to the beam optical design of this facility. The beam line consists of mainly the electrostatic quadrupoles, an accelerating section, analyzing cum switching magnet and suitable beam diagnostics including vacuum components. The accelerated ion beam is analyzed for a particular mass to charge (m/q) ratio as well as guided to three different lines along 75°, 90° and 105° using a large acceptance analyzing cum switching magnet. The details of transverse beam optics to all the beam lines with TRANSPORT and GICOSY beam optics codes are being described. Field computation code, OPERA 3D has been utilized to design the magnets and electrostatic quadrupoles. A theoretical estimation of emittance for optimized geometry of ion source is given so as to form the basis of beam optics calculations. The method of quadrupole scan of the beam is used to characterize the emittance of the final beam on the target. The measured beam emittance increases with m/q ratios of various ion beams similar to the trend observed theoretically.

  7. Study of beam-beam effects in eRHIC

    SciTech Connect

    Hao, Y.; Litvinenko, V.; Ptitsyn, V.

    2010-05-23

    Beam-beam effects in eRHIC have a number of unique features, which distinguish them from both hadron and lepton colliders. Due to beam-beam interaction, both electron and hadron beams would suffer quality degradation or beam loss from without proper treatments. Those features need novel study and dedicate countermeasures. We study the beam dynamics and resulting luminosity of the characteristics, including mismatch, disruption and pinch effects on electron beam, in additional to their consequences on the opposing beam as a wake field and other incoherent effects of hadron beam. We also carry out countermeasures to prevent beam quality degrade and coherent instability.

  8. An intense polarized beam by a laser ionization injection

    NASA Astrophysics Data System (ADS)

    Ohmori, Chihiro; Hiramatsu, Shigenori; Nakamura, Takeshi

    1990-12-01

    Accumulation of protons and polarized protons by photo-ionization injection are described. This method consists of: (1) producing the neutral hydrogen beam by Lorentz stripping; (2) excitation of the neutral hydrogen beam with a laser; and (3) ionization of the hydrogen beam in the 2P excited state with another laser. When the laser for the excitation is circularly polarized, we can get a polarized proton beam. An ionization efficiency of 98 percent and a polarization of 80 percent can be expected by an intense laser beam from a free electron laser (FEL).

  9. Beam transport with magnetic solenoids and plasma lenses

    SciTech Connect

    Noble, R.J.

    1988-10-01

    We examine the behavior of axisymmetric space-charge dominated beams in transport lines using numerical simulation. A typical transport line consisting of two axisymmetric linear lenses used to make a continuous beam from an ion source to a radio frequency quadrupole (RFQ) is considered. We compare the beam evolution when both lenses are magnetic solenoids or Gabor plasma lenses for beams with different initial density profiles. Emittance oscillations due to nonlinear space-charge forces by the action of plasma lenses in which space-charge fields are shielded, but beam mismatch at the RFQ entrance can be significant for both types of lens. 8 refs., 6 figs.

  10. Variable beam shaping with using the same field mapping refractive beam shaper

    NASA Astrophysics Data System (ADS)

    Laskin, Alexander; Laskin, Vadim

    2012-02-01

    Modern laser scientific techniques and industrial technologies require not only simple homogenizing of a beam but also more freedom in manipulation of intensity profile and generating such profiles like super-Gaussian, inverse-Gaussian, skewed flattop and others. In many cases the task of variable beam shaping can be solved by refractive beam shaping optics of field mapping type which operational principle presumes saving of beam consistency, providing collimated output beam of low divergence, high transmittance and flatness of output beam profile, extended depth of field; another important feature is negligible residual wave aberration. Typically the fields mapping refractive beam shapers, like πShaper, are designed to generate flattop intensity profile for a beam of pre-determined size and input intensity profile. Varying of the input beam diameter lets it possible to realize either super-Gaussian (smaller input) or inverse-Gaussian (bigger input) intensity profiles of output beam that are important in pumping of solid-state lasers, hardening, cladding and other techniques. By lateral shift of a beam with respect to a πShaper the output flattop profile gets a skew in direction of that shift, the skew angle corresponds to the shift value. The skewed profile is important, for example, in some acousto-optical techniques where compensation of acoustic wave attenuation is required. All variety of profiles can be provided by the same beam shaper unit. This paper will describe some design basics of refractive beam shapers of the field mapping type and techniques to vary the output intensity profile, experimental results will be presented as well.

  11. Dual beam optical interferometer

    NASA Technical Reports Server (NTRS)

    Gutierrez, Roman C. (Inventor)

    2003-01-01

    A dual beam interferometer device is disclosed that enables moving an optics module in a direction, which changes the path lengths of two beams of light. The two beams reflect off a surface of an object and generate different speckle patterns detected by an element, such as a camera. The camera detects a characteristic of the surface.

  12. Cooling of Stored Beams

    SciTech Connect

    Mills, F.

    1986-06-10

    Beam cooling methods developed for the accumulation of antiprotons are being employed to assist in the performance of experiments in Nuclear and Particle Physics with ion beams stored in storage rings. The physics of beam cooling, and the ranges of utility of stochastic and electron cooling are discussed in this paper.

  13. Electromagnetic nonuniformly correlated beams.

    PubMed

    Tong, Zhisong; Korotkova, Olga

    2012-10-01

    A class of electromagnetic sources with nonuniformly distributed field correlations is introduced. The conditions on source parameters guaranteeing that the source generates a physical beam are derived. It is shown that the new sources are capable of producing beams with polarization properties that evolve on propagation in a manner much more complex compared to the well-known electromagnetic Gaussian Schell-model beams.

  14. Electron beam device

    DOEpatents

    Beckner, E.H.; Clauser, M.J.

    1975-08-12

    This patent pertains to an electron beam device in which a hollow target is symmetrically irradiated by a high energy, pulsed electron beam about its periphery and wherein the outer portion of the target has a thickness slightly greater than required to absorb the electron beam pulse energy. (auth)

  15. Beam injection into RHIC

    SciTech Connect

    Fischer, W.; Hahn, H.; MacKay, W.W.; Satogata, T.; Tsoupas, N.; Zhang, W.

    1997-07-01

    During the RHIC sextant test in January 1997 beam was injected into a sixth of one of the rings for the first time. The authors describe the injection zone and its bottlenecks. They report on the commissioning of the injection system, on beam based measurements of the kickers and the application program to steer the beam.

  16. ATA beam director experiment

    SciTech Connect

    Lee, E.P.; Younger, F.C.; Cruz, G.E.; Nolting, E.

    1986-06-23

    This report describes beam director elements for an experiment at the Advanced Test Accelerator. The elements described include a vernier magnet for beam aiming, an achromat magnet, and an isolation system for the beam interface. These components are built at small scale for concept testing. (JDH)

  17. Beam particle tracking for MUSE

    NASA Astrophysics Data System (ADS)

    Liyanage, Anusha; MUSE Collaboration

    2017-01-01

    The proton radius puzzle is the 7 σ disagreement between the proton radius extracted from the measured muonic hydrogen Lamb shift and the proton radius extracted from the regular hydrogen Lamb shift and elastic ep scattering form factor data. So far there is no generally accepted resolution to the puzzle. The explanations for the discrepancy include new degrees of freedom beyond the Standard Model. The MUon Scattering Experiment (MUSE) will simultaneously measure ep and μp scattering at the Paul Scherrer Institute, using the πM1 beam line at 100-250 MeV/c to cover a four-momentum transfer range of Q2=0.002-0.07 (GeV/c)2. Due to the large divergence of the secondary muon beam, beam particle trajectories are needed for every event. They are measured by a Gas Electron Multiplier (GEM) tracking telescope consisting of three 10x10 cm2 triple-GEM chambers. Fast segmented scintillator paddles provide precise timing information. The GEM detectors, their performance in test beam times, and plans and milestones will be discussed. This work has been supported by DOE DE-SC0012589 and NSF HRD-1649909. DOE DE-SC0012589 and NSF HRD-1649909.

  18. Beam-beam interaction working group summary

    SciTech Connect

    Siemann, R.H.

    1995-03-01

    The limit in hadron colliders is understood phenomenologically. The beam-beam interaction produces nonlinear resonances and makes the transverse tunes amplitude dependent. Tune spreads result from the latter, and as long as these tune spreads do not overlap low order resonances, the lifetime and performance is acceptable. Experience is that tenth and sometimes twelfth order resonances must be avoided, and the hadron collider limit corresponds roughly to the space available between resonances of that and lower order when operating near the coupling resonance. The beam-beam interaction in e{sup +}e{sup {minus}} colliders is not understood well. This affects the performance of existing colliders and could lead to surprises in new ones. For example. a substantial amount of operator tuning is usually required to reach the performance limit given above, and this tuning has to be repeated after each major shutdown. The usual interpretation is that colliding beam performance is sensitive to small lattice errors, and these are being reduced during tuning. It is natural to ask what these errors are, how can a lattice be characterized to minimize tuning time, and what aspects of a lattice should receive particular attention when a new collider is being designed. The answers to this type of question are not known, and developing ideas for calculations, simulations and experiments that could illuminate the details of the beam-beam interaction was the primary working group activity.

  19. Halo formation from mismatched beam-beam interactions

    SciTech Connect

    Qiang, Ji

    2003-05-23

    In this paper, we report on the halo formation and emittance growth driven by a parametric resonance during mismatched beam-beam collisions. In the regime of the weak-strong beam-beam interaction, if two beams have the same machine tunes, on-axis head-on collisions between a mismatched strong beam and a weak beam will not cause the formation of halo. However, if the two beams collide with an initial offset, the beam-beam force from the mismatched strong beam can cause halo formation and emittance growth in the weak beam. Meanwhile, if two beams have different machine tunes, for opposite charged colliding beams, when the machine tune of the weak beam is smaller than that of strong beam, there is emittance growth in the weak beam. When the machine tune of the weak beam is larger than that of the strong beam, there is little emittance growth. In the regime of strong-strong beam-beam interaction, halo is formed in both beams even when the two beams collide head-on on the axis with equal machine tunes. This puts a strong requirement for a good beam match during the injection to colliders in order to avoid the emittance growth.

  20. Status of RHIC head-on beam-beam compensation project

    SciTech Connect

    Fischer, W.; Anerella, M.; Beebe, E.; Bruno, D.; Gassner, D.M.; Gu, X.; Gupta, R.C.; Hock, J.; Jain, A.K.; Lambiase, R.; Liu, C.; Luo, Y.; Mapes, M.; Montag, C.; Oerter, B.; Okamura, M.; Pikin, A.I.; Raparia, D.; Tan, Y.; Than, R.; Thieberger, P.; Tuozzolo, J.; Zhang, W.

    2011-03-28

    Two electron lenses are under construction for RHIC to partially compensate the head-on beam-beam effect in order to increase both the peak and average luminosities. The final design of the overall system is reported as well as the status of the component design, acquisition, and manufacturing. An overview of the RHIC head-on beam-beam compensation project is given in [1], and more details in [2]. With 2 head-on beam-beam interactions in IP6 and IP8, a third interaction with a low-energy electron beam is added near IP10 to partially compensate the the head-on beam-beam effect. Two electron lenses are under construction, one for each ring. Both will be located in a region common to both beams, but each lens will act only on one beam. With head-on beam-beam compensation up to a factor of two improvement in luminosity is expected together with a polarized source upgrade. The current RHIC polarized proton performance is documented in Ref. [4]. An electron lens (Fig. 1) consists of an DC electron gun, warm solenoids to focus the electron beam during transport, a superconducting main solenoid in which the interaction with the proton beam occurs, steering magnets, a collector, and instrumentation. The main developments in the last year are given below. The experimental program for polarized program at 100 GeV was expected to be finished by the time the electron lenses are commissioned. However, decadal plans by the RHIC experiments STAR and PHENIX show a continuing interest at both 100 GeV and 250 GeV, and a larger proton beam size has been accommodated in the design (Tab. 1). Over the last year beam and lattice parameters were optimized, and RHIC proton lattices are under development for optimized electron lens performance. The effect of the electron lens magnetic structure on the proton beam was evaluated, and found to be correctable. Experiments were done in RHIC and the Tevatron.

  1. BEAM CONTROL PROBE

    DOEpatents

    Chesterman, A.W.

    1959-03-17

    A probe is described for intercepting a desired portion of a beam of charged particles and for indicating the spatial disposition of the beam. The disclosed probe assembly includes a pair of pivotally mounted vanes moveable into a single plane with adjacent edges joining and a calibrated mechanical arrangement for pivoting the vancs apart. When the probe is disposed in the path of a charged particle beam, the vanes may be adjusted according to the beam current received in each vane to ascertain the dimension of the beam.

  2. A Sagnac-like interferometer for the generation of vector beams

    NASA Astrophysics Data System (ADS)

    Wang, Tonglu; Fu, Shiyao; Zhang, Shikun; Gao, Chunqing; He, Feng

    2016-09-01

    In this paper, we propose a Sagnac-like scheme, to transform Laguerre-Gaussian (LG) beams into vector beams. The experimental apparatus of our scheme consists of a polarized beam splitter, two reflectors, and a quarter-wave plate (QWP). Firstly, holograms of spiral phase plates were encoded on a liquid crystal spatial light modulator to generate different LG beams. Then, the generated LG beams were transformed into radially polarized vector beams. Azimuthally polarized vector beams were also obtained through placing a half-wave plate group behind the QWP. The intensity distribution of the generated vector beams is similar to the incident LG beams. A rotating polarizer is used to analyze the polarization distribution of the generated vector beams, and the results of which are highly consistent with the theoretical analysis.

  3. Consistency, Understanding and Truth in Educational Research

    ERIC Educational Resources Information Center

    Davis, Andrew

    2006-01-01

    What do Elliot Eisner's discussions of objectivity mean for the strength of the link between consistency and truth in educational research? Following his lead, I pursue this question by comparing aspects of qualitative educational research with appraising the arts. I argue that some departures from the highest levels of consistency in assessing…

  4. 40 CFR 55.12 - Consistency updates.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 5 2011-07-01 2011-07-01 false Consistency updates. 55.12 Section 55.12 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) OUTER CONTINENTAL SHELF AIR REGULATIONS § 55.12 Consistency updates. (a) The Administrator will...

  5. Categories Influence Predictions about Individual Consistency

    ERIC Educational Resources Information Center

    Rhodes, Marjorie; Gelman, Susan A.

    2008-01-01

    Predicting how people will behave in the future is a critical social-cognitive task. In four studies (N = 150, ages preschool to adult), young children (ages 4-5) used category information to guide their expectations about individual consistency. They predicted that psychological properties (preferences and fears) would remain consistent over time…

  6. Consistency and Enhancement Processes in Understanding Emotions

    ERIC Educational Resources Information Center

    Stets, Jan E.; Asencio, Emily K.

    2008-01-01

    Many theories in the sociology of emotions assume that emotions emerge from the cognitive consistency principle. Congruence among cognitions produces good feelings whereas incongruence produces bad feelings. A work situation is simulated in which managers give feedback to workers that is consistent or inconsistent with what the workers expect to…

  7. Development of a 50 MW Multiple Beam Klystron

    SciTech Connect

    Ives, R Lawrence; Ferguson, Patrick; Read, Michael; Collins, George

    2007-10-31

    The goal of this program was to develop a 50 MW, multiple beam klystron at 11.424 GHz. The device uses eight electron guns and beam lines to achieve the required power level at a beam voltage of 190 kV, consistent with solid state power supplies. The electron gun operates with confined flow focusing, which is unique among current multiple beam sources, and allows operation at power levels consistent with producing 10s of MWs of pulsed RF power. The circuit consists of a ring resonator input cavity, eight sets of buncher cavities, and a ring resonator output cavity. The RF output power is coupled into four rectangular waveguides equally spaced around the klystron. Eight individual collectors absorb the spent beam power in each beam. The klystron operates in a solenoid. The principle challenges in the design included development of the beam optics using confined flow focusing, shaping of the magnetic field in the gun region to avoid beam spiraling, coupling input power equally to all eight beam lines from a single input, and obtaining the required frequency and Q in the output cavity. The mechanical design was particularly complex due to the large parts count, number of braze and weld joints, and close proximity of the beam lines that limited access. Addressing vacuum leaks and cold testing the complex structures was particularly troublesome. At the conclusion of the program, the klystron is experiencing several vacuum leaks that are under repair. Efforts will continue to seal and test the klystron.

  8. Managing consistency in collaborative design environments

    NASA Astrophysics Data System (ADS)

    Miao, Chunyan; Yang, Zhonghua; Goh, Angela; Sun, Chengzheng; Sattar, Abdul

    1999-08-01

    In today's global economy, there is a significant paradigm shift to collaborative engineering design environments. One of key issues in the collaborative setting is the consistency model, which governs how to coordinate the activities of collaborators to ensure that they do not make inconsistent changes or updates to the shared objects. In this paper, we present a new consistency model which requires that all update operations will be executed in the casual order (causality) and all participants have the same view on the operations on the shared objects (view synchrony). A simple multicast-based protocol to implement the consistency model is presented. By employing vector time and token mechanisms, the protocol brings the shared objects from one consistent state to another, thus providing collaborators with a consistent view of the shared objects. A CORBA-based on-going prototyping implementation is outlined. Some of the related work are also discussed.

  9. Beam envelope matching for beam guidance systems

    SciTech Connect

    Brown, K.L.

    1980-08-01

    Ray optics and phase ellipse optics are developed as tools for designing charged particle beam guidance systems. Specific examples of basic optical systems and of phase ellipse matching are presented as illustrations of these mathematical techniques.

  10. Refractive beam shapers for focused laser beams

    NASA Astrophysics Data System (ADS)

    Laskin, Alexander; Laskin, Vadim; Ostrun, Aleksei

    2016-09-01

    Focusing of laser radiation is most often used approach in various industrial micromachining applications like scribing, PCB drilling, and is important in scientific researches like laser heating in geophysics experiments with diamond anvil cells (DAC). Control of intensity distribution in focal spot is important task since optimum intensity profiles are rather flat-top, doughnut or "inverse-Gauss" than typical for lasers Gaussian profile. Because of high intensity of modern CW and pulsed lasers it is advisable to use refractive beam shaping optics with smooth optical surfaces providing high radiation resistance. Workable optical solutions can be built on the base of diffraction theory conclusion that flat-top intensity profile in focal plane of a lens is created when input beam has Airy-disk intensity distribution. It is suggested to apply refractive beam shapers converting, with minimum wavefront deformation, Gaussian profile of TEM00 beam to a beam with Airy disk intensity distribution, thereby optimizing conditions of interference near the focal plane of a lens after the beam shaper and providing flat-top, doughnut, "inverse-Gauss" profiles. This approach allows operation with CW and ultra-short pulse lasers, using F-theta lenses and objectives, mirror scanners, provides extended depth of field similar to Rayleigh length of comparable TEM00 beam, easy integration in industrial equipment, simple adjustment procedure and switching between profiles, telescope and collimator implementations. There will be considered design basics of beam shapers, analysis of profile behaviour near focal plane, examples of implementations in micromachining systems and experimental DAC setups, results of profile measurements and material processing.

  11. Bolt beam propagation analysis

    NASA Astrophysics Data System (ADS)

    Shokair, I. R.

    BOLT (Beam on Laser Technology) is a rocket experiment to demonstrate electron beam propagation on a laser ionized plasma channel across the geomagnetic field in the ion focused regime (IFR). The beam parameters for BOLT are: beam current I(sub b) = 100 Amps, beam energy of 1--1.5 MeV (gamma =3-4), and a Gaussian beam and channel of radii r(sub b) = r(sub c) = 1.5 cm. The N+1 ionization scheme is used to ionize atomic oxygen in the upper atmosphere. This scheme utilizes 130 nm light plus three IR lasers to excite and then ionize atomic oxygen. The limiting factor for the channel strength is the energy of the 130 nm laser, which is assumed to be 1.6 mJ for BOLT. At a fixed laser energy and altitude (fixing the density of atomic oxygen), the range can be varied by adjusting the laser tuning, resulting in a neutralization fraction axial profile of the form: f(z) = f(sub 0) e(exp minus z)/R, where R is the range. In this paper we consider the propagation of the BOLT beam and calculate the range of the electron beam taking into account the fact that the erosion rates (magnetic and inductive) vary with beam length as the beam and channel dynamically respond to sausage and hose instabilities.

  12. Ensuring the Consistency of Silicide Coatings

    NASA Technical Reports Server (NTRS)

    Ramani, V.; Lampson, F. K.

    1982-01-01

    Diagram specifies optimum fusing time for given thicknesses of refractory metal-silicide coatings on columbium C-103 substrates. Adherence to indicated fusion times ensures consistent coatings and avoids underdiffusion and overdiffusion. Accuracy of diagram has been confirmed by tests.

  13. On the initial state and consistency relations

    SciTech Connect

    Berezhiani, Lasha; Khoury, Justin E-mail: jkhoury@sas.upenn.edu

    2014-09-01

    We study the effect of the initial state on the consistency conditions for adiabatic perturbations. In order to be consistent with the constraints of General Relativity, the initial state must be diffeomorphism invariant. As a result, we show that initial wavefunctional/density matrix has to satisfy a Slavnov-Taylor identity similar to that of the action. We then investigate the precise ways in which modified initial states can lead to violations of the consistency relations. We find two independent sources of violations: i) the state can include initial non-Gaussianities; ii) even if the initial state is Gaussian, such as a Bogoliubov state, the modified 2-point function can modify the q-vector → 0 analyticity properties of the vertex functional and result in violations of the consistency relations.

  14. Transverse beam emittance measurement using quadrupole variation at KIRAMS-430

    NASA Astrophysics Data System (ADS)

    An, Dong Hyun; Hahn, Garam; Park, Chawon

    2015-02-01

    In order to produce a 430 MeV/u carbon ion (12 C 6+) beam for medical therapy, the Korea Institute of Radiological & Medical Sciences (KIRAMS) has carried out the development of a superconducting isochronous cyclotron, the KIRAMS-430. At the extraction of the cyclotron, an Energy Selection System (ESS) is located to modulate the fixed beam energy and to drive the ion beam through High Energy Beam Transport (HEBT) into the treatment room. The beam emittance at the ion beamline is to be measured to provide information on designing a beam with high quality. The well-known quadrupole variation method was used to determine the feasibility of measuring the transverse beam emittance. The beam size measured at the beam profile monitor (BPM) is to be utilized and the transformation of beam by transfer matrix is to be applied being taken under various transport condition of varying quadrupole magnetic strength. Two different methods where beam optics are based on the linear matrix formalism and particle tracking with a 3-D magnetic field distribution obtained by using OPERA3D TOSCA, are applied to transport the beam. The fittings for the transformation parameters are used to estimate the transverse emittance and the twiss parameters at the entrance of the quadrupole in the ESS. Including several systematic studies, we conclude that within the uncertainty the estimated emittances are consistent with the ones calculated by using Monte Carlo simulations.

  15. Initial Tests of a Plasma Beam Combiner at NIF

    NASA Astrophysics Data System (ADS)

    Kirkwood, R. K.; Turnbull, D. P.; Chapman, T. D.; Wilks, S. C.; London, R. A.; Berger, R. L.; Michel, P. A.; Divol, L.; Dunlop, W. H.; MacGowan, B. J.; Fournier, K. B.; Blue, B. E.; NIF Team

    2016-10-01

    The seeded forward SBS process that is known to effectively amplify beams in ignition targets has recently been used to design and test a target to combine the power and energy of many beams of the NIF facility into a single beam by intersecting them in an ionized gas. The demand for high-power beams for a variety of applications at NIF makes a demonstration of this process attractive. We will describe experiments using a gas-filled balloon heated by 10 quads of beams, and pumped by additional frequency-tuned quads to amplify a single beam. The beam energy is indicated by gated x-ray images of both the spots produced by the transmitted pump and probe beams and the spot produced by a non-interacting quad of beams when they terminate on a foil. The first experiment produced a high brightness seed beam with significant reductions in brightness of the pumping beams, consistent with their depletion by energy transfer to the seed. Additional experiments studying spot brightness with varying pump power to determine total delivered seed beam energy and power will be discussed as available. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  16. DEVELOPMENT OF EMITTANCE ANALYSIS SOFTWARE FOR ION BEAM CHARACTERIZATION

    SciTech Connect

    Padilla, M. J.; Liu, Y.

    2007-01-01

    Transverse beam emittance is a crucial property of charged particle beams that describes their angular and spatial spread. It is a fi gure of merit frequently used to determine the quality of ion beams, the compatibility of an ion beam with a given beam transport system, and the ability to suppress neighboring isotopes at on-line mass separator facilities. Generally a high quality beam is characterized by a small emittance. In order to determine and improve the quality of ion beams used at the Holifi eld Radioactive Ion beam Facility (HRIBF) for nuclear physics and nuclear astrophysics research, the emittances of the ion beams are measured at the off-line Ion Source Test Facilities. In this project, emittance analysis software was developed to perform various data processing tasks for noise reduction, to evaluate root-mean-square emittance, Twiss parameters, and area emittance of different beam fractions. The software also provides 2D and 3D graphical views of the emittance data, beam profi les, emittance contours, and RMS. Noise exclusion is essential for accurate determination of beam emittance values. A Self-Consistent, Unbiased Elliptical Exclusion (SCUBEEx) method is employed. Numerical data analysis techniques such as interpolation and nonlinear fi tting are also incorporated into the software. The software will provide a simplifi ed, fast tool for comprehensive emittance analysis. The main functions of the software package have been completed. In preliminary tests with experimental emittance data, the analysis results using the software were shown to be accurate.

  17. Safety performance functions incorporating design consistency variables.

    PubMed

    Montella, Alfonso; Imbriani, Lella Liana

    2015-01-01

    Highway design which ensures that successive elements are coordinated in such a way as to produce harmonious and homogeneous driver performances along the road is considered consistent and safe. On the other hand, an alignment which requires drivers to handle high speed gradients and does not meet drivers' expectancy is considered inconsistent and produces higher crash frequency. To increase the usefulness and the reliability of existing safety performance functions and contribute to solve inconsistencies of existing highways as well as inconsistencies arising in the design phase, we developed safety performance functions for rural motorways that incorporate design consistency measures. Since the design consistency variables were used only for curves, two different sets of models were fitted for tangents and curves. Models for the following crash characteristics were fitted: total, single-vehicle run-off-the-road, other single vehicle, multi vehicle, daytime, nighttime, non-rainy weather, rainy weather, dry pavement, wet pavement, property damage only, slight injury, and severe injury (including fatal). The design consistency parameters in this study are based on operating speed models developed through an instrumented vehicle equipped with a GPS continuous speed tracking from a field experiment conducted on the same motorway where the safety performance functions were fitted (motorway A16 in Italy). Study results show that geometric design consistency has a significant effect on safety of rural motorways. Previous studies on the relationship between geometric design consistency and crash frequency focused on two-lane rural highways since these highways have the higher crash rates and are generally characterized by considerable inconsistencies. Our study clearly highlights that the achievement of proper geometric design consistency is a key design element also on motorways because of the safety consequences of design inconsistencies. The design consistency measures

  18. Path-consistency: When space misses time

    SciTech Connect

    Chmeiss, A.; Jegou, P.

    1996-12-31

    Within the framework of constraint programming, particulary concerning the Constraint Satisfaction Problems (CSPs), the techniques of preprocessing based on filtering algorithms were shown to be very important for the search phase. In particular, two filtering methods have been studied, these methods exploit two properties of local consistency: arc- and path-consistency. Concerning the arc-consistency methods, there is a linear time algorithm (in the size of the problem) which is efficient in practice. But the limitations of the arc-consistency algorithms requires often filtering methods with higher order like path-consistency filterings. The best path-consistency algorithm proposed is PC-6, a natural generalization of AC-6 to path-consistency. Its time complexity is O(n{sup 3}d{sup 4}) and its space complexity is O(n{sup 3}d{sup 4}), where n is the number of variables and d is the size of domains. We have remarked that PC-6, though it is widely better than PC-4, was not very efficient in practice, specially for those classes of problems that require an important space to be run. Therefore, we propose here a new path-consistency algorithm called PC-7, its space complexity is O(n{sup 3}d{sup 4}) but its time complexity is O(n{sup 3}d{sup 4}) i.e. worse than that of PC-6. However, the simplicity of PC-7 as well as the data structures used for its implementation offer really a higher performance than PC-6. Furthermore, it turns out that when the size of domains is a constant of the problems, the time complexity of PC-7 becomes. like PC-6, optimal i.e. O(n{sup 3}).

  19. Three-Way Tucker2 Component Analysis Solutions of Stimuli x Responses x Individuals Data with Simple Structure and the Fewest Core Differences

    ERIC Educational Resources Information Center

    Adachi, Kohei

    2011-01-01

    Multivariate stimulus-response designs can be described by a three-way array of stimuli by responses by individuals. Its underlying structure can be represented by a network based on the Tucker2 component model in which stimulus components are connected with response components by means of the links that differ between individuals. For each…

  20. Distinct reactivity of Morita-Baylis-Hillman acetates as a novel C(2) component in amine-catalyzed [2 + 2 + 2] and [2 + 4] annulations.

    PubMed

    Chen, Rongshun; Xu, Silong; Wang, Liyi; Tang, Yuhai; He, Zhengjie

    2013-05-04

    Amine-catalyzed [2 + 2 + 2] and [2 + 4] annulations of Morita-Baylis-Hillman (MBH) acetates with cyano activated alkenes and 1,3-azadienes have been developed to provide cyclohexanes and tetrahydropyridines. In the annulations, MBH acetates serve as a novel C(2) component with an inactive homoallylic methyl involved in the bond formation.

  1. High resolution beam profile monitors in the SLC

    SciTech Connect

    Ross, M.C.; Seeman, J.T.; Jobe, R.K.; Sheppard, J.C.; Stiening, R.F.

    1985-04-01

    In the SLC linac, low emittance beams with typical transverse dimensions less than 0.2 mm must be accelerated without effective emittance growth. In order to monitor this we have installed a high resolution beam profile monitor system which consists of an aluminum target covered with a fine-grained phosphor, a magnifying optical system, a television camera and video signal recording electronics. The image formed when the beam strikes the phosphor screen is viewed on a CRT monitor at the console and selected horizontal and vertical slices of the beam spot intensity are recorded. A 20 MHz transient waveform recorder is used to sample and digitize the raw video signal along the selected slice. The beam width is determined by fitting the background subtracted data to a Gaussian. Beam spots less than 6 x 3 mm can be viewed. Beam spot sizes sigma/sub x,y/ < 80 ..mu..m have been measured. 9 refs., 4 figs.

  2. Prebunched-beam free electron maser

    NASA Astrophysics Data System (ADS)

    Arbel, M.; Ben-Chaim, D.; Cohen, M.; Draznin, M.; Eichenbaum, A.; Gover, Abraham; Kleinman, H.; Kugel, A.; Pinhasi, Yosef; Witman, S.; Yakover, Y. M.

    1994-05-01

    The development status of a prebunched FEM is described. We are developing a 70 KeV FEM to allow high gain wideband operation and to enable variation of the degree of prebunching. We intend to investigate its operation as an amplifier and as an oscillator. Effects of prebunching, frequency variation, linear and nonlinear effects, will be investigated. The prebuncher consists of a Pierce e-gun followed by a beam modulating section. The prebunched beam is accelerated to 70 KeV and injected into a planar wiggler containing a waveguide. The results obtained to date will be presented. These include: characterization of the e-gun, e-beam transport to and through the wiggler, use of field modifying permanent magnets near the entrance and along the wiggler to obtain good e-beam transport through the wiggler, waveguide selection and characterization.

  3. SPS Beam Steering for LHC Extraction

    SciTech Connect

    Gianfelice-Wendt, Eliana; Bartosik, Hannes; Cornelis, Karel; Norderhaug Drøsdal, Lene; Goddard, Brennan; Kain, Verena; Meddahi, Malika; Papaphilippou, Yannis; Wenninger, Jorg

    2014-07-01

    The CERN Super Proton Synchrotron accelerates beams for the Large Hadron Collider to 450 GeV. In addition it produces beams for fixed target facilities which adds complexity to the SPS operation. During the run 2012-2013 drifts of the extracted beam trajectories have been observed and lengthy optimizations in the transfer lines were performed to reduce particle losses in the LHC. The observed trajectory drifts are consistent with the measured SPS orbit drifts at extraction. While extensive studies are going on to understand, and possibly suppress, the source of such SPS orbit drifts the feasibility of an automatic beam steering towards a “golden” orbit at the extraction septa, by means of the interlocked correctors, is also being investigated. The challenges and constraints related to the implementation of such a correction in the SPS are described. Simulation results are presented and a possible operational steering strategy is proposed.

  4. Scaling of the beam-plasma discharge

    NASA Technical Reports Server (NTRS)

    Rowland, H. L.; Papadopoulos, K.; Chang, C. L.

    1981-01-01

    A theoretical analysis is presented of the scaling of the critical beam current required for ignition and the narrow band emissions observed for beam currents less than critical in a beam plasma discharge experiment. The theory of the two-stream interaction between a nonrelativistic cold electron beam and a plasma in the presence of a magnetic field is developed, and conditions for the two-stream instability and the resulting amplification are derived. It is shown that the experimentally observed scaling is consistent with the assumption that the ignition triggering occurs when an instability near the electron plasma frequency is excited. Finally, it is shown that the wave emissions observed in the subthreshold range can be explained by the excitation of the kinetic instability of the upper branch and convective saturation.

  5. Self-consistent asset pricing models

    NASA Astrophysics Data System (ADS)

    Malevergne, Y.; Sornette, D.

    2007-08-01

    We discuss the foundations of factor or regression models in the light of the self-consistency condition that the market portfolio (and more generally the risk factors) is (are) constituted of the assets whose returns it is (they are) supposed to explain. As already reported in several articles, self-consistency implies correlations between the return disturbances. As a consequence, the alphas and betas of the factor model are unobservable. Self-consistency leads to renormalized betas with zero effective alphas, which are observable with standard OLS regressions. When the conditions derived from internal consistency are not met, the model is necessarily incomplete, which means that some sources of risk cannot be replicated (or hedged) by a portfolio of stocks traded on the market, even for infinite economies. Analytical derivations and numerical simulations show that, for arbitrary choices of the proxy which are different from the true market portfolio, a modified linear regression holds with a non-zero value αi at the origin between an asset i's return and the proxy's return. Self-consistency also introduces “orthogonality” and “normality” conditions linking the betas, alphas (as well as the residuals) and the weights of the proxy portfolio. Two diagnostics based on these orthogonality and normality conditions are implemented on a basket of 323 assets which have been components of the S&P500 in the period from January 1990 to February 2005. These two diagnostics show interesting departures from dynamical self-consistency starting about 2 years before the end of the Internet bubble. Assuming that the CAPM holds with the self-consistency condition, the OLS method automatically obeys the resulting orthogonality and normality conditions and therefore provides a simple way to self-consistently assess the parameters of the model by using proxy portfolios made only of the assets which are used in the CAPM regressions. Finally, the factor decomposition with the

  6. Generation of stochastic electromagnetic beams with complete controllable coherence.

    PubMed

    Chen, Xudong; Chang, Chengcheng; Chen, Ziyang; Lin, Zhili; Pu, Jixiong

    2016-09-19

    We generate a stochastic electromagnetic beam (SEB) with complete controllable coherence, that is, the coherence degree can be controlled independently along two mutually perpendicular directions. We control the coherence of the SEB by adjusting the phase modulation magnitude applied onto two crossed phase only spatial light modulators. We measure the beam's coherence properties using Young's interference experiment, as well as the beam propagation factor. It is shown that the experimental results are consistent with our theoretical predictions.

  7. Toward design of the Collider Beam Collimation System

    SciTech Connect

    Drozhdin, A.; Mokhov, N.; Soundranayagam, R.; Tompkins, J.

    1994-02-01

    A multi-component beam collimation system for the Superconducting Super Collider is described. System choice justification and design requirements are presented. System consists of targets, scrapers, and collimators with appropriate cooling and radiation shielding. Each component has an independent control for positioning and aligning with respect to the beam. Results of beam loss distribution, energy deposition calculations, and thermal analyses, as well as cost estimate, are presented.

  8. Craft Stick Beams

    NASA Technical Reports Server (NTRS)

    Karplus, Alan K.

    1996-01-01

    The objective of this exercise is to provide a phenomenological 'hands-on' experience that shows how geometry can affect the load carrying capacity of a material used in construction, how different materials have different failure characteristics, and how construction affects the performance of a composite material. This will be accomplished by building beams of a single material and composite beams of a mixture of materials (popsicle sticks, fiberboard sheets, and tongue depressors); testing these layered beams to determine how and where they fail; and based on the failure analysis, designing a layered beam that will fail in a predicted manner. The students will learn the effects of lamination, adhesion, and geometry in layered beam construction on beam strength and failure location.

  9. Particle beam injection system

    DOEpatents

    Jassby, Daniel L.; Kulsrud, Russell M.

    1977-01-01

    This invention provides a poloidal divertor for stacking counterstreaming ion beams to provide high intensity colliding beams. To this end, method and apparatus are provided that inject high energy, high velocity, ordered, atomic deuterium and tritium beams into a lower energy, toroidal, thermal equilibrium, neutral, target plasma column that is magnetically confined along an endless magnetic axis in a strong restoring force magnetic field having helical field lines to produce counterstreaming deuteron and triton beams that are received bent, stacked and transported along the endless axis, while a poloidal divertor removes thermal ions and electrons all along the axis to increase the density of the counterstreaming ion beams and the reaction products resulting therefrom. By balancing the stacking and removal, colliding, strong focused particle beams, reaction products and reactions are produced that convert one form of energy into another form of energy.

  10. Focused Bessel beams

    SciTech Connect

    Adamson, P V

    2000-04-30

    The diffraction broadening of a focused beam with a Bessel amplitude distribution is examined. Calculations are reported not only of the traditional differential characteristics (radial distributions of the electric-energy densities and of the axial total electromagnetic energy flux in the beam), but also of integral quantities characterising the degree of transverse localisation of the radiation in a tube of specified radius within the beam. It is shown that in a large-aperture Bessel beam only a very small fraction of the total beam power is concentrated in its central core and that a focal point is also observed on intense focusing of the Bessel beam. This spot is not in the geometric-optical focal plane but is displaced from the latter by a certain distance. (laser applications and other topics in quantum electronics)

  11. Three-dimensional particle trajectories and waste beam losses in injection dump beam line of SNS accumulator ring

    SciTech Connect

    Wang, Jian-Guang; Plum, Michael A

    2008-01-01

    The SNS ring injection dump beam line has been suffering high beam losses since its commissioning. In order to understand the mechanisms of the beam losses, we have performed 3D simulation studies of the beam line. The 3D models consist of three injection chicane dipoles and one injection dump septum magnet. 3D particle trajectories in the models are computed. We then extend particle optics calculations to the injection dump. Our studies have clearly shown some design and operation problems, that cause beam losses in the injection dump beam line. These include incorrect chicane dipole settings, incorrect position of a chicane dipole, too small aperture of injection dump septum, and inadequate focusing downstream. This paper reports our findings and the remedies to the injection beam loss problems.

  12. Entropy-based consistent model driven architecture

    NASA Astrophysics Data System (ADS)

    Niepostyn, Stanisław Jerzy

    2016-09-01

    A description of software architecture is a plan of the IT system construction, therefore any architecture gaps affect the overall success of an entire project. The definitions mostly describe software architecture as a set of views which are mutually unrelated, hence potentially inconsistent. Software architecture completeness is also often described in an ambiguous way. As a result most methods of IT systems building comprise many gaps and ambiguities, thus presenting obstacles for software building automation. In this article the consistency and completeness of software architecture are mathematically defined based on calculation of entropy of the architecture description. Following this approach, in this paper we also propose our method of automatic verification of consistency and completeness of the software architecture development method presented in our previous article as Consistent Model Driven Architecture (CMDA). The proposed FBS (Functionality-Behaviour-Structure) entropy-based metric applied in our CMDA approach enables IT architects to decide whether the modelling process is complete and consistent. With this metric, software architects could assess the readiness of undergoing modelling work for the start of IT system building. It even allows them to assess objectively whether the designed software architecture of the IT system could be implemented at all. The overall benefit of such an approach is that it facilitates the preparation of complete and consistent software architecture more effectively as well as it enables assessing and monitoring of the ongoing modelling development status. We demonstrate this with a few industry examples of IT system designs.

  13. Symmetric smoothing filters from global consistency constraints.

    PubMed

    Haque, Sheikh Mohammadul; Pai, Gautam P; Govindu, Venu Madhav

    2015-05-01

    Many patch-based image denoising methods can be viewed as data-dependent smoothing filters that carry out a weighted averaging of similar pixels. It has recently been argued that these averaging filters can be improved using their doubly stochastic approximation, which are symmetric and stable smoothing operators. In this paper, we introduce a simple principle of consistency that argues that the relative similarities between pixels as imputed by the averaging matrix should be preserved in the filtered output. The resultant consistency filter has the theoretically desirable properties of being symmetric and stable, and is a generalized doubly stochastic matrix. In addition, we can also interpret our consistency filter as a specific form of Laplacian regularization. Thus, our approach unifies two strands of image denoising methods, i.e., symmetric smoothing filters and spectral graph theory. Our consistency filter provides high-quality image denoising and significantly outperforms the doubly stochastic version. We present a thorough analysis of the properties of our proposed consistency filter and compare its performance with that of other significant methods for image denoising in the literature.

  14. Design study of low-energy beam transport for multi-charge beams at RAON

    NASA Astrophysics Data System (ADS)

    Bahng, Jungbae; Qiang, Ji; Kim, Eun-San

    2015-12-01

    The Rare isotope Accelerator Of Newness (RAON) at the Rare Isotope Science Project (RISP) is being designed to simultaneously accelerate beams with multiple charge states. It includes a driver superconducting (SC) linac for producing 200 MeV/u and 400 kW continuous wave (CW) heavy ion beams from protons to uranium. The RAON consists of a few electron cyclotron resonance ion sources, a low-energy beam transport (LEBT) system, a CW 81.25 MHz, 500 keV/u radio frequency quadrupole (RFQ) accelerator, a medium-energy beam transport system, the SC linac, and a charge-stripper system. The LEBT system for the RISP accelerator facility consists of a high-voltage platform, two 90° dipoles, a multi-harmonic buncher (MHB), solenoids, electrostatic quadrupoles, a velocity equalizer, and a diagnostic system. The ECR ion sources are located on a high-voltage platform to reach an initial beam energy of 10 keV/u. After extraction, the ion beam is transported through the LEBT system to the RFQ accelerator. The generated charge states are selected by an achromatic bending system and then bunched by the MHB in the LEBT system. The MHB is used to achieve a small longitudinal emittance in the RFQ by generating a sawtooth wave with three harmonics. In this paper, we present the results and issues of the beam dynamics of the LEBT system.

  15. Contributions to the mini-workshop on beam-beam compensation in the Tevatron

    SciTech Connect

    Shiltsev, V.

    1998-02-01

    The purpose of the Workshop was to assay the current understanding of compensation of the beam-beam effects in the Tevatron with use of low-energy high-current electron beam, relevant accelerator technology, along with other novel techniques of the compensation and previous attempts. About 30 scientists representing seven institutions from four countries--FNAL, SLAC, BNL, Novosibirsk, CERN, and Dubna were in attendance. Twenty one talks were presented. The event gave firm ground for wider collaboration on experimental test of the compensation at the Tevatron collider. This report consists of vugraphs of talks given at the meeting.

  16. Reduction of beam hardening artifacts in cone-beam CT imaging via SMART-RECON algorithm

    NASA Astrophysics Data System (ADS)

    Li, Yinsheng; Garrett, John; Chen, Guang-Hong

    2016-03-01

    When an automatic exposure control is introduced in C-arm cone beam CT data acquisition, the spectral inconsistencies between acquired projection data are exacerbated. As a result, conventional water/bone correction schemes are not as effective as in conventional diagnostic x-ray CT acquisitions with a fixed tube potential. In this paper, a new method was proposed to reconstruct several images with different degrees of spectral consistency and thus different levels of beam hardening artifacts. The new method relies neither on prior knowledge of the x-ray beam spectrum nor on prior compositional information of the imaging object. Numerical simulations were used to validate the algorithm.

  17. Electromagnetic ion beam instabilities

    NASA Technical Reports Server (NTRS)

    Gary, S. P.; Foosland, D. W.; Smith, C. W.; Lee, M. A.; Goldstein, M. L.

    1984-01-01

    The linear theory of electromagnetic instabilities driven by an energetic ion beam streaming parallel to a magnetic field in a homogeneous Vlasov plasma is considered. Numerical solutions of the full dispersion equation are presented. At propagation parallel to the magnetic field, there are four distinct instabilities. A sufficiently energetic beam gives rise to two unstable modes with right-hand polarization, one resonant with the beam, the other nonresonant. A beam with sufficiently large T (perpendicular to B)/T (parallel to B) gives rise to the left-hand ion cyclotron anisotropy instability at relatively small beam velocities, and a sufficiently hot beam drives unstable a left-hand beam resonant mode. The parametric dependences of the growth rates for the three high beam velocity instabilities are presented here. In addition, some properties at oblique propagation are examined. It is demonstrated that, as the beam drift velocity is increased, relative maxima in growth rates can arise at harmonics of the ion cyclotron resonance for both right and left elliptically polarized modes.

  18. Pulsed ion beam source

    DOEpatents

    Greenly, John B.

    1996-01-01

    An improved magnetically-confined anode plasma pulsed ion beam source. Beam rotation effects and power efficiency are improved by a magnetic design which places the separatrix between the fast field flux structure and the slow field structure near the anode of the ion beam source, by a gas port design which localizes the gas delivery into the gap between the fast coil and the anode, by a pre-ionizer ringing circuit connected to the fast coil, and by a bias field means which optimally adjusts the plasma formation position in the ion beam source.

  19. Power beaming options

    NASA Technical Reports Server (NTRS)

    Rather, John D. G.

    1989-01-01

    Some large scale power beaming applications are proposed for the purpose of stimulating research. The first proposal is for a combination of large phased arrays on the ground near power stations and passive reflectors in geostationary orbit. The systems would beam excess electrical power in microwave form to areas in need of electrical power. Another proposal is to build solar arrays in deserts and beam the energy around the world. Another proposal is to use lasers to beam energy from earth to orbiting spacecraft.

  20. Plasma Beam Measurements

    DTIC Science & Technology

    1991-08-01

    GUN PLASMA BEAM / ,I 21 cm diameter = 0 GLASS DRIFT TUBE 50 cm diameter MCP CAMERA CLASS CROSSES (a) Gun muzzle /"- PLASA BEAM / TAROT z = 10 m MCP...discusses some of the hydrodynamic issues related to the calcula- tions. The reader may well wonder why hydrodynamics should be an issue in a 116 WL-TR-90...answer is yes for the slow beam cases and no for the fast beam cases. This is explained further. 118 WL-TR-90-83 The reader will recall the

  1. Broad beam ion implanter

    DOEpatents

    Leung, K.N.

    1996-10-08

    An ion implantation device for creating a large diameter, homogeneous, ion beam is described, as well as a method for creating same, wherein the device is characterized by extraction of a diverging ion beam and its conversion by ion beam optics to an essentially parallel ion beam. The device comprises a plasma or ion source, an anode and exit aperture, an extraction electrode, a divergence-limiting electrode and an acceleration electrode, as well as the means for connecting a voltage supply to the electrodes. 6 figs.

  2. Broad beam ion implanter

    DOEpatents

    Leung, Ka-Ngo

    1996-01-01

    An ion implantation device for creating a large diameter, homogeneous, ion beam is described, as well as a method for creating same, wherein the device is characterized by extraction of a diverging ion beam and its conversion by ion beam optics to an essentially parallel ion beam. The device comprises a plasma or ion source, an anode and exit aperture, an extraction electrode, a divergence-limiting electrode and an acceleration electrode, as well as the means for connecting a voltage supply to the electrodes.

  3. (Pulsed electron beam precharger)

    SciTech Connect

    Finney, W.C.; Shelton, W.N.

    1990-01-01

    This report discusses the following topics on electron beam guns: Precharger Modification; Installation of Charge vs. Radius Apparatus; High Concentration Aerosol Generation; and Data Acquisition and Analysis System.

  4. Transport of 3D space charge dominated beams

    NASA Astrophysics Data System (ADS)

    Lü, Jian-Qin

    2013-10-01

    In this paper we present the theoretical analysis and the computer code design for the intense pulsed beam transport. Intense beam dynamics is a very important issue in low-energy high-current accelerators and beam transport systems. This problem affects beam transmission and beam qualities. Therefore, it attracts the attention of the accelerator physicists worldwide. The analysis and calculation for the intense beam dynamics are very complicated, because the state of particle motion is dominated not only by the applied electromagnetic fields, but also by the beam-induced electromagnetic fields (self-fields). Moreover, the self fields are related to the beam dimensions and particle distributions. So, it is very difficult to get the self-consistent solutions of particle motion analytically. For this reason, we combine the Lie algebraic method and the particle in cell (PIC) scheme together to simulate intense 3D beam transport. With the Lie algebraic method we analyze the particle nonlinear trajectories in the applied electromagnetic fields up to third order approximation, and with the PIC algorithm we calculate the space charge effects to the particle motion. Based on the theoretical analysis, we have developed a computer code, which calculates beam transport systems consisting of electrostatic lenses, electrostatic accelerating columns, solenoid lenses, magnetic and electric quadruples, magnetic sextupoles, octopuses and different kinds of electromagnetic analyzers. The optimization calculations and the graphic display for the calculated results are provided by the code.

  5. Personalized recommendation based on unbiased consistence

    NASA Astrophysics Data System (ADS)

    Zhu, Xuzhen; Tian, Hui; Zhang, Ping; Hu, Zheng; Zhou, Tao

    2015-08-01

    Recently, in physical dynamics, mass-diffusion-based recommendation algorithms on bipartite network provide an efficient solution by automatically pushing possible relevant items to users according to their past preferences. However, traditional mass-diffusion-based algorithms just focus on unidirectional mass diffusion from objects having been collected to those which should be recommended, resulting in a biased causal similarity estimation and not-so-good performance. In this letter, we argue that in many cases, a user's interests are stable, and thus bidirectional mass diffusion abilities, no matter originated from objects having been collected or from those which should be recommended, should be consistently powerful, showing unbiased consistence. We further propose a consistence-based mass diffusion algorithm via bidirectional diffusion against biased causality, outperforming the state-of-the-art recommendation algorithms in disparate real data sets, including Netflix, MovieLens, Amazon and Rate Your Music.

  6. Quantifying the Consistency of Scientific Databases

    PubMed Central

    Šubelj, Lovro; Bajec, Marko; Mileva Boshkoska, Biljana; Kastrin, Andrej; Levnajić, Zoran

    2015-01-01

    Science is a social process with far-reaching impact on our modern society. In recent years, for the first time we are able to scientifically study the science itself. This is enabled by massive amounts of data on scientific publications that is increasingly becoming available. The data is contained in several databases such as Web of Science or PubMed, maintained by various public and private entities. Unfortunately, these databases are not always consistent, which considerably hinders this study. Relying on the powerful framework of complex networks, we conduct a systematic analysis of the consistency among six major scientific databases. We found that identifying a single "best" database is far from easy. Nevertheless, our results indicate appreciable differences in mutual consistency of different databases, which we interpret as recipes for future bibliometric studies. PMID:25984946

  7. Dynamically consistent Jacobian inverse for mobile manipulators

    NASA Astrophysics Data System (ADS)

    Ratajczak, Joanna; Tchoń, Krzysztof

    2016-06-01

    By analogy to the definition of the dynamically consistent Jacobian inverse for robotic manipulators, we have designed a dynamically consistent Jacobian inverse for mobile manipulators built of a non-holonomic mobile platform and a holonomic on-board manipulator. The endogenous configuration space approach has been exploited as a source of conceptual guidelines. The new inverse guarantees a decoupling of the motion in the operational space from the forces exerted in the endogenous configuration space and annihilated by the dual Jacobian inverse. A performance study of the new Jacobian inverse as a tool for motion planning is presented.

  8. Results of Beam Extraction Performance for the KSTAR Neutral Beam Injector

    NASA Astrophysics Data System (ADS)

    Chang, Doo-Hee; Jeong, Seung Ho; Kim, Tae-Seong; Lee, Kwang Won; Ryul In, Sang; Jin, Jung-Tae; Chang, Dae-Sik; Oh, Byung-Hoon; Bae, Young-Soon; Kim, Jong-Su; Cho, Wook; Park, Hyun-Taek; Park, Young-Min; Yang, Hyung-Lyeol; Watanabe, Kazuhiro; Dairaku, Masayuki; Tobari, Hiroyuki; Kashiwagi, Mieko; Hanada, Masaya; Inoue, Takashi

    2011-06-01

    The first neutral beam injector (NBI-1) has been developed for the Korea Superconducting Tokamak Advanced Research (KSTAR) tokamak. The first long pulse ion source (LPIS-1) has been installed on the NBI-1 for an auxiliary heating and current drive of KSTAR plasmas. The performance of ion and neutral beam extractions in the LPIS-1 was investigated initially on the KSTAR NBI-1 system, prior to the neutral beam injection into the main plasmas. The ion source consists of a magnetic bucket plasma generator with multipole cusp fields and a set of prototype tetrode accelerators with circular apertures. The inner volume of the plasma generator and accelerator column in the LPIS-1 is approximately 123 L. Design requirements for the ion source were a 120 kV/65 A deuterium beam and a 300 s pulse length. The extraction of ion beams was initiated by the formation of arc plasmas in the LPIS-1, called the arc-beam extraction method. A stable ion beam extraction of the LPIS-1 was achieved up to 85 kV/32 A for a 5 s pulse length and 80 kV/25 A for a 14 s pulse length. An optimum beam perveance of 1.15 µperv was observed at an acceleration voltage of 60 kV. Neutralization efficiency was measured by a water-flow calorimetry (WFC) method using a calorimeter and the operation of a bending magnet. The full-energy species of ion beams were detected by using the diagnostic method of optical multichannel analyzer (OMA). An arc efficiency of the LPIS was 0.6-1.1 A/kW depending on the operating conditions of arc discharge. A neutral beam power of ˜1.0 MW must be sufficiently injected into the KSTAR plasmas from the LPIS-1 at a beam energy of 80 keV.

  9. H{sup -} beam transport experiments in a solenoid low energy beam transport

    SciTech Connect

    Gabor, C.; Back, J. J.; Faircloth, D. C.; Lawrie, S. R.; Letchford, A. P.; Izaola, Z.

    2012-02-15

    The Front End Test Stand (FETS) is located at Rutherford Appleton Laboratory and aims for a high current, fast chopped 3 MeV H{sup -} ion beam suitable for future high power proton accelerators like ISIS upgrade. The main components of the front end are the Penning ion source, a low energy beam transport line, an radio-frequency quadrupole (RFQ) and a medium energy beam transport (MEBT) providing also a chopper section and rebuncher. FETS is in the stage of commissioning its low energy beam transport (LEBT) line consisting of three solenoids. The LEBT has to transport an H{sup -} high current beam (up to 60 mA) at 65 keV. This is the injection energy of the beam into the RFQ. The main diagnostics are slit-slit emittance scanners for each transversal plane. For optimizing the matching to the RFQ, experiments have been performed with a variety of solenoid settings to better understand the actual beam transport. Occasionally, source parameters such as extractor slit width and beam energy were varied as well. The paper also discusses simulations based on these measurements.

  10. BEAM STOP DESIGN METHODOLOGY AND DESCRIPTION OF A NEW SNS BEAM STOP

    SciTech Connect

    Polsky, Yarom; Plum, Michael A; Geoghegan, Patrick J; Jacobs, Lorelei L; Lu, Wei; McTeer, Stephen Mark

    2010-01-01

    The design of accelerator components such as magnets, accelerator cavities and beam instruments tends to be a fairly standardized and collective effort within the particle accelerator community with well established performance, reliability and, in some cases, even budgetary criteria. Beam stop design, by contrast, has been comparatively subjective historically with much more general goals. This lack of rigor has lead to a variety of facility implementations with limited standardization and minimal consensus on approach to development within the particle accelerator community. At the Spallation Neutron Source (SNS), for example, there are four high power beam stops in use, three of which have significantly different design solutions. This paper describes the design of a new off-momentum beam stop for the SNS. The technical description of the system will be complemented by a discussion of design methodology. This paper presented an overview of the new SNS HEBT off-momentum beam stop and outlined a methodology for beam stop system design. The new beam stop consists of aluminium and steel blocks cooled by a closed-loop forced-air system and is expected to be commissioned this summer. The design methodology outlined in the paper represents a basic description of the process, data, analyses and critical decisions involved in the development of a beam stop system.

  11. Development of a focused ion beam micromachining system

    SciTech Connect

    Pellerin, J.G.; Griffis, D.; Russell, P.E.

    1988-12-01

    Focused ion beams are currently being investigated for many submicron fabrication and analytical purposes. An FIB micromachining system consisting of a UHV vacuum system, a liquid metal ion gun, and a control and data acquisition computer has been constructed. This system is being used to develop nanofabrication and nanomachining techniques involving focused ion beams and scanning tunneling microscopes.

  12. The two-beam accelertor

    SciTech Connect

    Sessler, A.M.; Hopkins, D.B.

    1987-08-01

    The Two-Beam Accelerator (TBA) consists of a long high-gradient accelerator structure (HGS) adjacent to an equal-length Free Electron Laser (FEL). In the FEL, a beam propagates through a long series of undulators. At regular intervals, waveguides couple microwave power out of the FEL into the HGS. To replenish energy given up by the FEL beam to the microwave field induction accelerator units are placed periodically along the length or the FEL. In this manner it is expected to achieve gradients of more than 250 MV/m and thus have serious option for a 1 TeV /times/ 1 TeV linear collider. The state of present theoretical understanding of the TBA is presented with particular emphasis upon operation of the ''steady-state'' FEL, phase and amplitude control of the rf wave, and suppression of sideband instabilities. Experimental work has focused upon the development of a suitable HGS and the testing of this structure using the Electron Laser Facility (ELF). Description is given of a first test at ELF with a seven-cell 2..pi../3 mode structure which without pre-conditioning and with a not-very-good vacuum nevertheless at 35 GHz yielded an average accelerating gradient of 180 MV/m.

  13. The Two-beam accelerator

    SciTech Connect

    Sessler, A.M.; Hopkins, D.B.

    1986-06-01

    The Two-Beam Accelerator (TBA) consists of a long high-gradient accelerator structure (HGS) adjacent to an equal-length Free Electron Laser (FEL). In the FEL, a beam propagates through a long series of undulators. At regular intervals, waveguides couple microwave power out of the FEL into the HGS. To replenish energy given up by the FEL beam to the microwave field, induction accelerator units are placed periodically along the length of the FEL. In this manner it is expected to achieve gradients of more than 250 MV/m and thus have a serious option for a 1 TeV x 1 TeV linear collider. The state of present theoretical understanding of the TBA is presented with particular emphasis upon operation of the ''steady-state'' FEL, phase and amplitude control of the rf wave, and suppression of sideband instabilities. Experimental work has focused upon the development of a suitable HGS and the testing of this structure using the Electron Laser Facility (ELF). Description is given of a first test at ELF with a seven-cell 2..pi../3 mode structure which without preconditioning and with a not-very-good vacuum nevertheless at 35 GHz yielded an average accelerating gradient of 180 MV/m.

  14. Image recognition and consistency of response

    NASA Astrophysics Data System (ADS)

    Haygood, Tamara M.; Ryan, John; Liu, Qing Mary A.; Bassett, Roland; Brennan, Patrick C.

    2012-02-01

    Purpose: To investigate the connection between conscious recognition of an image previously encountered in an experimental setting and consistency of response to the experimental question.
    Materials and Methods: Twenty-four radiologists viewed 40 frontal chest radiographs and gave their opinion as to the position of a central venous catheter. One-to-three days later they again viewed 40 frontal chest radiographs and again gave their opinion as to the position of the central venous catheter. Half of the radiographs in the second set were repeated images from the first set and half were new. The radiologists were asked of each image whether it had been included in the first set. For this study, we are evaluating only the 20 repeated images. We used the Kruskal-Wallis test and Fisher's exact test to determine the relationship between conscious recognition of a previously interpreted image and consistency in interpretation of the image.
    Results. There was no significant correlation between recognition of the image and consistency in response regarding the position of the central venous catheter. In fact, there was a trend in the opposite direction, with radiologists being slightly more likely to give a consistent response with respect to images they did not recognize than with respect to those they did recognize.
    Conclusion: Radiologists' recognition of previously-encountered images in an observer-performance study does not noticeably color their interpretation on the second encounter.

  15. Consistent Visual Analyses of Intrasubject Data

    ERIC Educational Resources Information Center

    Kahng, SungWoo; Chung, Kyong-Mee; Gutshall, Katharine; Pitts, Steven C.; Kao, Joyce; Girolami, Kelli

    2010-01-01

    Visual inspection of single-case data is the primary method of interpretation of the effects of an independent variable on a dependent variable in applied behavior analysis. The purpose of the current study was to replicate and extend the results of DeProspero and Cohen (1979) by reexamining the consistency of visual analysis across raters. We…

  16. Consistency of Students' Explanations about Combustion.

    ERIC Educational Resources Information Center

    Watson, J. Rod; Prieto, Teresa; Dillon, Justin S.

    1997-01-01

    Reports on a study of 14-15 year old students' ideas about combustion. Describes patterns of students' explanations across a range of questions and analyzes them to gain insight into both the degree of consistency of their explanations and how this may affect the process of conceptual change in the students. (Contains 35 references.) (Author/YDS)

  17. 36 CFR 241.22 - Consistency determinations.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... FISH AND WILDLIFE Conservation of Fish, Wildlife, and Their Habitat, Chugach National Forest, Alaska... conservation of fish, wildlife, and their habitat. A use or activity may be determined to be consistent if it will not materially interfere with or detract from the conservation of fish, wildlife and their...

  18. Environmental Decision Support with Consistent Metrics

    EPA Science Inventory

    One of the most effective ways to pursue environmental progress is through the use of consistent metrics within a decision making framework. The US Environmental Protection Agency’s Sustainable Technology Division has developed TRACI, the Tool for the Reduction and Assessment of...

  19. Cross-Cultural Comparison of Cognitive Consistency.

    ERIC Educational Resources Information Center

    Khokhlov, Nikolai E.; Gonzalez E. John

    1973-01-01

    A comparison of cognitive consistency was conducted across two cultural groups. Forty-five American subjects in Southern California and 45 subjects in Northern Greece responded to a questionnaire written in their native language and which contained three classical paradigms for balance theory. It was hypothesized that significant differences in…

  20. Developing consistent time series landsat data products

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Landsat series satellite has provided earth observation data record continuously since early 1970s. There are increasing demands on having a consistent time series of Landsat data products. In this presentation, I will summarize the work supported by the USGS Landsat Science Team project from 20...

  1. 36 CFR 241.22 - Consistency determinations.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... FISH AND WILDLIFE Conservation of Fish, Wildlife, and Their Habitat, Chugach National Forest, Alaska... conservation of fish, wildlife, and their habitat. A use or activity may be determined to be consistent if it will not materially interfere with or detract from the conservation of fish, wildlife and their...

  2. Consistent gravitational anomalies for chiral bosons

    SciTech Connect

    Giaccari, Stefano; Menotti, Pietro

    2009-03-15

    Exact consistent gravitational anomalies for chiral bosons in two dimensions are treated both with the Schwinger-DeWitt regularization and independently through a cohomological procedure. The diffeomorphism transformations are described by a single ghost which allows one to climb the cohomological chain in a unique way.

  3. Consistency of Toddler Engagement across Two Settings

    ERIC Educational Resources Information Center

    Aguiar, Cecilia; McWilliam, R. A.

    2013-01-01

    This study documented the consistency of child engagement across two settings, toddler child care classrooms and mother-child dyadic play. One hundred twelve children, aged 14-36 months (M = 25.17, SD = 6.06), randomly selected from 30 toddler child care classrooms from the district of Porto, Portugal, participated. Levels of engagement were…

  4. 36 CFR 241.22 - Consistency determinations.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 36 Parks, Forests, and Public Property 2 2014-07-01 2014-07-01 false Consistency determinations. 241.22 Section 241.22 Parks, Forests, and Public Property FOREST SERVICE, DEPARTMENT OF AGRICULTURE FISH AND WILDLIFE Conservation of Fish, Wildlife, and Their Habitat, Chugach National Forest,...

  5. 36 CFR 241.22 - Consistency determinations.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 36 Parks, Forests, and Public Property 2 2012-07-01 2012-07-01 false Consistency determinations. 241.22 Section 241.22 Parks, Forests, and Public Property FOREST SERVICE, DEPARTMENT OF AGRICULTURE FISH AND WILDLIFE Conservation of Fish, Wildlife, and Their Habitat, Chugach National Forest,...

  6. 36 CFR 241.22 - Consistency determinations.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 36 Parks, Forests, and Public Property 2 2013-07-01 2013-07-01 false Consistency determinations. 241.22 Section 241.22 Parks, Forests, and Public Property FOREST SERVICE, DEPARTMENT OF AGRICULTURE FISH AND WILDLIFE Conservation of Fish, Wildlife, and Their Habitat, Chugach National Forest,...

  7. Properties and Update Semantics of Consistent Views

    DTIC Science & Technology

    1985-09-01

    8217 PR.OPERTIES AND UPDATE SEMANTICS OF CONSISTENT VIEWS G. Gottlob Institute for Applied Mathematics C.N.H.., G<•nova, Italy Compnt.<•r Sden... Gottlob G., Paolini P., Zicari R., "Proving Properties of Programs ou Database Views", Dipartiuwnto di Elcttronica, Politecnko di Milano (in

  8. Sonic Beam Model of Newton's Cradle

    ERIC Educational Resources Information Center

    Menger, Fredric M.; Rizvi, Syed A. A.

    2016-01-01

    The motions of Newton's cradle, consisting of several steel balls hanging side-by-side, have been analysed in terms of a sound pulse that travels via points of contact among the balls. This presupposes a focused energy beam. When the pulse reaches the fifth and final ball, the energy disperses and dislocates the ball with a trajectory equivalent…

  9. Gassmann-Consistency of Inclusion Models

    NASA Astrophysics Data System (ADS)

    Goebel, M.; Wollner, U.; Dvorkin, J. P.

    2015-12-01

    Mathematical inclusion theories predict the effective elastic properties of a porous medium with idealized-shape inclusions as a function of the elastic moduli of the host matrix and those of the inclusions. These effective elastic properties depend on the volumetric concentration of the inclusions (the porosity of the host frame) and the aspect ratio of an inclusion (the ratio between the thickness and length). Seemingly, these models can solve the problem of fluid substitution and solid substitution: any numbers can be used for the bulk and shear moduli of the inclusions, including zero for empty inclusions (dry rock). In contrast, the most commonly used fluid substitution method is Gassmann's (1951) theory. We explore whether inclusion based fluid substitution is consistent with Gassmann's fluid substitution. We compute the effective bulk and shear moduli of a matrix with dry inclusions and then conduct Gassmann's fluid substitution, comparing these results to those from directly computing the bulk and shear moduli of the same matrix but with the inclusions having the bulk modulus of the fluid. A number of examples employing the differential effective medium (DEM) model and self-consistent (SC) approximation indicate that the wet-rock bulk moduli as predicted by DEM and SC are approximately Gassmann-consistent at high aspect ratio and small porosity. However, at small aspect ratios and high porosity, these inclusion models are not Gassmann-consistent. For all cases, the shear moduli are not Gassmann-consistent at all, meaning that the wet-rock shear modulus as given by DEM or SC is very different from the dry-rock moduli as predicted by the same theories. We quantify the difference between the two methods for a range of porosity and aspect ratio combinations.

  10. Picosecond beam monitor

    DOEpatents

    Schutt, D.W.; Beck, G.O.

    1974-01-01

    The current in the beam of a particle accelerator is monitored with picosecond resolution by causing the beam to impinge upon the center conductor of a coaxial line, generating a pulse of electromagnetic energy in response thereto. This pulse is detected by means such as a sampling oscilloscope. (Official Gazette)

  11. Ion Beam Propulsion Study

    NASA Technical Reports Server (NTRS)

    2008-01-01

    The Ion Beam Propulsion Study was a joint high-level study between the Applied Physics Laboratory operated by NASA and ASRC Aerospace at Kennedy Space Center, Florida, and Berkeley Scientific, Berkeley, California. The results were promising and suggested that work should continue if future funding becomes available. The application of ion thrusters for spacecraft propulsion is limited to quite modest ion sources with similarly modest ion beam parameters because of the mass penalty associated with the ion source and its power supply system. Also, the ion source technology has not been able to provide very high-power ion beams. Small ion beam propulsion systems were used with considerable success. Ion propulsion systems brought into practice use an onboard ion source to form an energetic ion beam, typically Xe+ ions, as the propellant. Such systems were used for steering and correction of telecommunication satellites and as the main thruster for the Deep Space 1 demonstration mission. In recent years, "giant" ion sources were developed for the controlled-fusion research effort worldwide, with beam parameters many orders of magnitude greater than the tiny ones of conventional space thruster application. The advent of such huge ion beam sources and the need for advanced propulsion systems for exploration of the solar system suggest a fresh look at ion beam propulsion, now with the giant fusion sources in mind.

  12. Beam Injection into RHIC

    NASA Astrophysics Data System (ADS)

    Fischer, W.; Hahn, H.; Mackay, W. W.; Tsoupas, N.

    1997-05-01

    During the RHIC sextant test in January 1997 beam was injected into a sixth of one of the rings for the first time. We describe the injection zone and its bottlenecks, the application program to steer the beam and the injection kickers. We report on the commissioning of the injection systems and on measurements of the kickers.

  13. Laser beam generating apparatus

    DOEpatents

    Warner, B.E.; Duncan, D.B.

    1994-02-15

    Laser beam generating apparatus including a septum segment disposed longitudinally within the tubular structure of the apparatus is described. The septum provides for radiatively dissipating heat buildup within the tubular structure and for generating relatively uniform laser beam pulses so as to minimize or eliminate radial pulse delays (the chevron effect). 7 figures.

  14. Experiments with isomeric beams

    NASA Astrophysics Data System (ADS)

    Pfützner, M.; Grzywacz, R.; Lewitowicz, M.; Rykaczewski, K.

    1997-02-01

    The results of the search for μs-isomers performed with 112Sn and 86Kr beams at 60 MeV/nucleon with the LISE3 spectrometer at GANIL are summarized. Planned extension of these studies to high energy fragmentation reactions with the FRS separator at GSI is described. Some perspectives for experiments with isomeric beams at GSI are mentioned.

  15. Beam Diagnostics for FACET

    SciTech Connect

    Li, S.Z.; Hogan, M.J.; /SLAC

    2011-08-19

    FACET, the Facility for Advanced Accelerator and Experimental Tests, is a new facility being constructed in sector 20 of the SLAC linac primarily to study beam driven plasma wakefield acceleration beginning in summer 2011. The nominal FACET parameters are 23GeV, 3nC electron bunches compressed to about 20 {micro}m long and focussed to about 10 {micro}m wide. Characterization of the beam-plasma interaction requires complete knowledge of the incoming beam parameters on a pulse-to-pulse basis. FACET diagnostics include Beam Position Monitors, Toroidal current monitors, X-ray and Cerenkov based energy spectrometers, optical transition radiation (OTR) profile monitors and coherent transition radiation (CTR) bunch length measurement systems. The compliment of beam diagnostics and their expected performance are reviewed. Beam diagnostic measurements not only provide valuable insights to the running and tuning of the accelerator but also are crucial for the PWFA experiments in particular. Beam diagnostic devices are being set up at FACET and will be ready for beam commissioning in summer 2011.

  16. Laser beam generating apparatus

    DOEpatents

    Warner, B.E.; Duncan, D.B.

    1993-12-28

    Laser beam generating apparatus including a septum segment disposed longitudinally within the tubular structure of the apparatus. The septum provides for radiatively dissipating heat buildup within the tubular structure and for generating relatively uniform laser beam pulses so as to minimize or eliminate radial pulse delays (the chevron effect). 11 figures.

  17. Varying stopping and self-focusing of intense proton beams as they heat solid density matter

    NASA Astrophysics Data System (ADS)

    Kim, J.; McGuffey, C.; Qiao, B.; Wei, M. S.; Grabowski, P. E.; Beg, F. N.

    2016-04-01

    Transport of intense proton beams in solid-density matter is numerically investigated using an implicit hybrid particle-in-cell code. Both collective effects and stopping for individual beam particles are included through the electromagnetic fields solver and stopping power calculations utilizing the varying local target conditions, allowing self-consistent transport studies. Two target heating mechanisms, the beam energy deposition and Ohmic heating driven by the return current, are compared. The dependences of proton beam transport in solid targets on the beam parameters are systematically analyzed, i.e., simulations with various beam intensities, pulse durations, kinetic energies, and energy distributions are compared. The proton beam deposition profile and ultimate target temperature show strong dependence on intensity and pulse duration. A strong magnetic field is generated from a proton beam with high density and tight beam radius, resulting in focusing of the beam and localized heating of the target up to hundreds of eV.

  18. Laser beam alignment system

    DOEpatents

    Kasner, William H.; Racki, Daniel J.; Swenson, Clark E.

    1984-01-01

    A plurality of pivotal reflectors direct a high-power laser beam onto a workpiece, and a rotatable reflector is movable to a position wherein it intercepts the beam and deflects a major portion thereof away from its normal path, the remainder of the beam passing to the pivotal reflectors through an aperture in the rotating reflector. A plurality of targets are movable to positions intercepting the path of light traveling to the pivotal reflectors, and a preliminary adjustment of the latter is made by use of a low-power laser beam reflected from the rotating reflector, after which the same targets are used to make a final adjustment of the pivotal reflectors with the portion of the high-power laser beam passed through the rotating reflector.

  19. Entangled vector vortex beams

    NASA Astrophysics Data System (ADS)

    D'Ambrosio, Vincenzo; Carvacho, Gonzalo; Graffitti, Francesco; Vitelli, Chiara; Piccirillo, Bruno; Marrucci, Lorenzo; Sciarrino, Fabio

    2016-09-01

    Light beams having a vectorial field structure, or polarization, that varies over the transverse profile and a central optical singularity are called vector vortex (VV) beams and may exhibit specific properties such as focusing into "light needles" or rotation invariance. VV beams have already found applications in areas ranging from microscopy to metrology, optical trapping, nano-optics, and quantum communication. Individual photons in such beams exhibit a form of single-particle quantum entanglement between different degrees of freedom. On the other hand, the quantum states of two photons can be also entangled with each other. Here, we combine these two concepts and demonstrate the generation of quantum entanglement between two photons that are both in VV states: a form of entanglement between two complex vectorial fields. This result may lead to quantum-enhanced applications of VV beams as well as to quantum information protocols fully exploiting the vectorial features of light.

  20. Multisegment coherent beam combining

    NASA Astrophysics Data System (ADS)

    Neal, Daniel R.; Tucker, Steve D.; Morgan, R.; Smith, Tony G.; Warren, Mial E.; Gruetzner, James K.; Rosenthal, R. R.; Bentley, A. E.

    1995-08-01

    Scaling laser systems to large sizes for power beaming and other applications can sometimes be simplified by combining a number of smaller lasers. However, to fully utilize this scaling, coherent beam combination is necessary. This requires measuring and controlling each beam's pointing and phase relative to adjacent beams using an adaptive optical system. We have built a sub-scale brass-board to evaluate various methods for beam-combining. It includes a segmented adaptive optic and several different specialized wavefront sensors that are fabricated using diffractive optics methods. We have evaluated a number of different phasing algorithms, including hierarchical and matrix methods, and have demonstrated phasing of several elements. The system is currently extended to a large number of segments to evaluate various scaling methodologies.

  1. Beam director design report

    SciTech Connect

    Younger, F.C.

    1986-08-01

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

  2. Accuracy and Consistency of Respiratory Gating in Abdominal Cancer Patients

    SciTech Connect

    Ge, Jiajia; Santanam, Lakshmi; Yang, Deshan; Parikh, Parag J.

    2013-03-01

    Purpose: To evaluate respiratory gating accuracy and intrafractional consistency for abdominal cancer patients treated with respiratory gated treatment on a regular linear accelerator system. Methods and Materials: Twelve abdominal patients implanted with fiducials were treated with amplitude-based respiratory-gated radiation therapy. On the basis of daily orthogonal fluoroscopy, the operator readjusted the couch position and gating window such that the fiducial was within a setup margin (fiducial-planning target volume [f-PTV]) when RPM indicated “beam-ON.” Fifty-five pre- and post-treatment fluoroscopic movie pairs with synchronized respiratory gating signal were recorded. Fiducial motion traces were extracted from the fluoroscopic movies using a template matching algorithm and correlated with f-PTV by registering the digitally reconstructed radiographs with the fluoroscopic movies. Treatment was determined to be “accurate” if 50% of the fiducial area stayed within f-PTV while beam-ON. For movie pairs that lost gating accuracy, a MATLAB program was used to assess whether the gating window was optimized, the external-internal correlation (EIC) changed, or the patient moved between movies. A series of safety margins from 0.5 mm to 3 mm was added to f-PTV for reassessing gating accuracy. Results: A decrease in gating accuracy was observed in 44% of movie pairs from daily fluoroscopic movies of 12 abdominal patients. Three main causes for inaccurate gating were identified as change of global EIC over time (∼43%), suboptimal gating setup (∼37%), and imperfect EIC within movie (∼13%). Conclusions: Inconsistent respiratory gating accuracy may occur within 1 treatment session even with a daily adjusted gating window. To improve or maintain gating accuracy during treatment, we suggest using at least a 2.5-mm safety margin to account for gating and setup uncertainties.

  3. Beam dynamics and error study of the medium energy beam transport line in the Korea Heavy-Ion Medical Accelerator

    NASA Astrophysics Data System (ADS)

    Kim, Chanmi; Kim, Eun-San; Hahn, Garam

    2016-11-01

    The Korea Heavy Ion Medical Accelerator consists of an injector and a synchrotron for an ion medical accelerator that is the first carbon-ion therapy system in Korea. The medium energy beam transport(MEBT) line connects the interdigital H-mode drift tube linac and the synchrotron. We investigated the beam conditions after the charge stripper by using the LISE++ and the SRIM codes. The beam was stripped from C4+ into C6+ by using the charge stripper. We investigated the performance of a de-buncher in optimizing the energy spread and the beam distribution in z-dW/W (direction of beam progress-beam and energy) phase. We obtained the results of the tracking simulation and the error analysis by using the TRACK code. Possible misalignments and rotations of the magnets were considered in the simulations. States of the beam were examined when errors occurred in the magnets by the applying analytic fringe field model in TRACK code. The condition for the beam orbit was optimized by using correctors and profile monitors to correct the orbit. In this paper, we focus on the beam dynamics and the error studies dedicated to the MEBT beam line and show the optimized beam parameters for the MEBT.

  4. A probe for real-time images of particle beams and their analyses in a merged-beams apparatus

    NASA Technical Reports Server (NTRS)

    Forand, J. L.; Wahlin, E.; Depaola, B. D.; Dunn, G. H.; Timmer, C.

    1990-01-01

    A real-time charged particle beam probe was developed, which can be used both as a beam diagnostic (beam tuning) and to quantitatively determine the three-dimensional density distribution of a beam. The probe consists of a microchannel plate, an aluminized phosphor screen deposited on a fiber-optic faceplate, a flexible fiber-optic bundle, and a charge injection device (CID) in tandem. Digital or analog video output of the CID is fed into a computer or oscilloscope, respectively, for analysis or observation. The probe can be moved continuously along the beams' paths to obtain 'pictures' of the beam at any desired interval, thus giving three-dimensional form factors. The beams, singly or simultaneously, may be observed on the monitor facilitating the task of beam adjustment for optimum overlap. The digital output is used for quantitative computation of the beam overlaps. The device is linear with beam intensity, but the performance degrades with time due to beam damage of the microchannel plate.

  5. BEAMS3D Neutral Beam Injection Model

    NASA Astrophysics Data System (ADS)

    McMillan, Matthew; Lazerson, Samuel A.

    2014-09-01

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

  6. Consistent Numerical Expressions for Precession Formulae.

    NASA Astrophysics Data System (ADS)

    Soma, M.

    The precession formulae by Lieske et al. (1977) have been used since 1984 for calculating apparent positions and reducing astrometric observations of celestial objects. These formulae are based on the IAU (1976) Astronomical Constants, some of which deviate from their recently determined values. They are also derived using the secular variations of the ecliptic pole from Newcomb's theory, which is not consistent with the recent planetary theories. Accordingly Simon et al. (1994) developed new precession formulae using the recently determined astronomical constants and also being based on the new planetary theory VSOP87. There are two differing definitions of the ecliptic: ecliptic in the inertial sense and ecliptic in the rotating sense (Standish 1981). The ecliptic given by the VSOP87 theory is that in the inertial sense, but the value for obliquity Simon et al. used is the obliquity in the rotating sense. Therefore their precession formulae has inconsistency. This paper gives corrections for consistent precession formulae.

  7. Temporally consistent segmentation of point clouds

    NASA Astrophysics Data System (ADS)

    Owens, Jason L.; Osteen, Philip R.; Daniilidis, Kostas

    2014-06-01

    We consider the problem of generating temporally consistent point cloud segmentations from streaming RGB-D data, where every incoming frame extends existing labels to new points or contributes new labels while maintaining the labels for pre-existing segments. Our approach generates an over-segmentation based on voxel cloud connectivity, where a modified k-means algorithm selects supervoxel seeds and associates similar neighboring voxels to form segments. Given the data stream from a potentially mobile sensor, we solve for the camera transformation between consecutive frames using a joint optimization over point correspondences and image appearance. The aligned point cloud may then be integrated into a consistent model coordinate frame. Previously labeled points are used to mask incoming points from the new frame, while new and previous boundary points extend the existing segmentation. We evaluate the algorithm on newly-generated RGB-D datasets.

  8. Consistency Test and Constraint of Quintessence

    SciTech Connect

    Chen, Chien-Wen; Gu, Je-AN; Chen, Pisin; /SLAC /Taiwan, Natl. Taiwan U.

    2012-04-30

    In this paper we highlight our recent work in arXiv:0803.4504. In that work, we proposed a new consistency test of quintessence models for dark energy. Our test gave a simple and direct signature if certain category of quintessence models was not consistent with the observational data. For a category that passed the test, we further constrained its characteristic parameter. Specifically, we found that the exponential potential was ruled out at the 95% confidence level and the power-law potential was ruled out at the 68% confidence level based on the current observational data. We also found that the confidence interval of the index of the power-law potential was between -2 and 0 at the 95% confidence level.

  9. Consistency of a counterexample to Naimark's problem

    PubMed Central

    Akemann, Charles; Weaver, Nik

    2004-01-01

    We construct a C*-algebra that has only one irreducible representation up to unitary equivalence but is not isomorphic to the algebra of compact operators on any Hilbert space. This answers an old question of Naimark. Our construction uses a combinatorial statement called the diamond principle, which is known to be consistent with but not provable from the standard axioms of set theory (assuming that these axioms are consistent). We prove that the statement “there exists a counterexample to Naimark's problem which is generated by \\documentclass[10pt]{article} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{pmc} \\usepackage[Euler]{upgreek} \\pagestyle{empty} \\oddsidemargin -1.0in \\begin{document} \\begin{equation*}{\\aleph}_{1}\\end{equation*}\\end{document} elements” is undecidable in standard set theory. PMID:15131270

  10. On consistent truncations in = 2* holography

    NASA Astrophysics Data System (ADS)

    Balasubramanian, Venkat; Buchel, Alex

    2014-02-01

    Although Pilch-Warner (PW) gravitational renormalization group flow [1] passes a number of important consistency checks to be identified as a holographic dual to a large- N SU( N) = 2* supersymmetric gauge theory, it fails to reproduce the free energy of the theory on S 4, computed with the localization techniques. This disagreement points to the existence of a larger dual gravitational consistent truncation, which in the gauge theory flat-space limit reduces to a PW flow. Such truncation was recently identified by Bobev-Elvang-Freedman-Pufu (BEFP) [2]. Additional bulk scalars of the BEFP gravitation truncation might lead to destabilization of the finite-temperature deformed PW flows, and thus modify the low-temperature thermodynamics and hydrodynamics of = 2* plasma. We compute the quasinormal spectrum of these bulk scalar fields in the thermal PW flows and demonstrate that these modes do not condense, as long as the masses of the = 2* hypermultiplet components are real.

  11. Self-consistency in Capital Markets

    NASA Astrophysics Data System (ADS)

    Benbrahim, Hamid

    2013-03-01

    Capital Markets are considered, at least in theory, information engines whereby traders contribute to price formation with their diverse perspectives. Regardless whether one believes in efficient market theory on not, actions by individual traders influence prices of securities, which in turn influence actions by other traders. This influence is exerted through a number of mechanisms including portfolio balancing, margin maintenance, trend following, and sentiment. As a result market behaviors emerge from a number of mechanisms ranging from self-consistency due to wisdom of the crowds and self-fulfilling prophecies, to more chaotic behavior resulting from dynamics similar to the three body system, namely the interplay between equities, options, and futures. This talk will address questions and findings regarding the search for self-consistency in capital markets.

  12. Self-consistent structure of metallic hydrogen

    NASA Technical Reports Server (NTRS)

    Straus, D. M.; Ashcroft, N. W.

    1977-01-01

    A calculation is presented of the total energy of metallic hydrogen for a family of face-centered tetragonal lattices carried out within the self-consistent phonon approximation. The energy of proton motion is large and proper inclusion of proton dynamics alters the structural dependence of the total energy, causing isotropic lattices to become favored. For the dynamic lattice the structural dependence of terms of third and higher order in the electron-proton interaction is greatly reduced from static lattice equivalents.

  13. General solution of the supersymmetry consistency conditions

    NASA Astrophysics Data System (ADS)

    Piguet, O.; Sibold, K.; Schweda, M.

    1980-11-01

    Renormalization of (broken-) supersymmetry theories depends on the existence of a local functional solution, with appropriate power counting, to a system of functional differential equations derived from the quantum action principle (QAP). Using consistency conditions which also follow from the QAP, we prove the existence of such a local solution; its dimension ensures ultraviolet renormalizability, whereas infrared behaviour must be discussed from case to case.

  14. Consistency test on the cosmic evolution

    NASA Astrophysics Data System (ADS)

    Gong, Yan; Ma, Yin-Zhe; Zhang, Shuang-Nan; Chen, Xuelei

    2015-09-01

    We propose a new and robust method to test the consistency of the cosmic evolution given by a cosmological model. It is realized by comparing the combined quantity rdCMB/DVSN , which is derived from the comoving sound horizon rd from cosmic microwave background (CMB) measurements and the effective distance DV derived from low-redshift type-Ia supernovae (SNe Ia) data, with direct and independent rd/DV obtained by baryon acoustic oscillation (BAO) measurements at median redshifts. We apply this test method for the Λ cold dark matter (Λ CDM ) and w CDM models, and investigate the consistency of the derived value of rd/DV from Planck 2015 and the SN Ia data sets of Union2.1 and joint light-curve analysis (JLA) (z <1.5 ), and the rd/DV directly given by BAO data from six-degree-field galaxy survey (6dFGS), Sloan Digital Sky Survey Data Release 7 Main Galaxy Survey (SDSS-DR7 MGS), DR11 of SDSS-III, WiggleZ and Ly α forecast surveys from baryon oscillation spectroscopic data (BOSS) DR-11 over 0.1 consistent with the BAO and CMB measurements within 1 σ C.L. Future surveys will further tighten up the constraints significantly, and provide a stronger test on the consistency.

  15. 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.

    PubMed

    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.

  16. Phase stability of injection-locked beam of semiconductor lasers

    NASA Technical Reports Server (NTRS)

    Kwon, Jin Hyuk; Kim, Do Hoon; Schuster, Gregory; Lee, Ja H.

    1992-01-01

    An experiment on the phase stability of an injection locked beam was done by using AlGaAs semiconductor lasers. The coherence of two beams from master and slave lasers was measured by interference between the beams in the Twymann-Green interferometer. The phase change of the output beam of the slave laser as a function of the driving current was measured in a Mach-Zehnder interferometer consisting of the master and slave lasers, and a value of 2.5 radians/mA was obtained.

  17. Commissioning of polarized-proton and antiproton beams at Fermilab

    SciTech Connect

    Yokosawa, A.

    1988-05-04

    The author described the polarized-proton and polarized-antiproton beams up to 200 GeV/c at Fermilab. The beam line, called MP, consists of the 400-m long primary and 350-m long secondary beam line followed by 60-m long experimental hall. We discuss the characteristics of the polarized beams. The Fermilab polarization projects are designated at E-581/704 initiated and carried out by an international collaboration, Argonne (US), Fermilab (US), Kyoto-Kyushu-Hiroshima-KEK (Japan), LAPP (France), Northwestern University (US), Los Alamos Laboratory (US), Rice (US), Saclay (France), Serpukhov (USSR), INFN Trieste (Italy), and University of Texas (US).

  18. Neutrinos from PIon Beam Line, nuPIL

    SciTech Connect

    Lagrange, J. B.; Pasternak, J.; Bross, A.; Liu, A.

    2016-05-05

    LBNF-DUNE (Long Baseline Neutrino Facilities - Deep Underground Neutrino Experiment) is a project based at Fermilab to study neutrino oscillations. The current baseline regarding the neutrino production considers the conventional approach: a high energy proton beam hits a target, producing pions that are collected by a horn and that decay in a decay pipe. An alternative solution, called nuPIL (neutrinos from a Pion beam Line) consists of using a beam line to guide the pions to clean the beam and to put instrumentation to monitor it. This paper presents the concept and the first preliminary results.

  19. Beam Simulations for IRE and Driver-Status and Strategy

    SciTech Connect

    Friedman, A.; Grote, D.P.; Lee, E.P.; Sonnendrucker, E.

    2000-03-01

    The methods and codes employed in the U.S. Heavy Ion Fusion program to simulate the beams in an Integrated Research Experiments (IRE) facility and a fusion driver are presented in overview. A new family of models incorporating accelerating module impedance, multi-beam, and self-magnetic effects is described, and initial WARP3d particle simulations of beams using these models are presented. Finally, plans for streamlining the machine-design simulation sequence, and for simulating beam dynamics from the source to the target in a consistent and comprehensive manner, are described.

  20. Beam Simulations for IRE and Driver - Status and Strategy

    SciTech Connect

    Friedman, A; Grote, D P; Lee, E P

    2001-03-13

    The methods and codes employed in the U.S. Heavy Ion Fusion program to simulate the beams in an Integrated Research Experiments (IRE) facility and a fusion driver are presented in overview. A new family of models incorporating accelerating module impedance, multi-beam, and self-magnetic effects is described, and initial WARP3d particle simulations of beams using these models are presented. Finally, plans for streamlining the machine-design simulation sequence, and for simulating beam dynamics from the source to the target in a consistent and comprehensive manner, are described.

  1. ALPI Setup as the SPES Accelerator of Exotic Beams

    NASA Astrophysics Data System (ADS)

    Bisoffi, G.; Bassato, G.; Battistella, A.; Bermudez, J.; Bortolato, D.; Canella, S.; Chalykh, B.; Comunian, M.; Facco, A.; Fagotti, E.; Galatà, A.; Giacchini, M.; Gramegna, F.; Lamy, T.; Modanese, P.; Palmieri, A.; Pengo, R.; Pisent, A.; Poggi, M.; Porcellato, A.; Roncolato, C.; Scarpa, D.

    2014-03-01

    The SPES (Selective Production of Exotic Species) project for a national exotic beam facility in Legnaro includes pivotal upgrades of the existing superconducting linac ALPI (Acceleratore Lineare Per Ioni), to make it appropriate as the RIB (Radioactive Ion Beam) accelerator. The new injector, consisting of an Electron Cyclotron Resonance (ECR)-type charge breeder and a radiofrequency quadrupole (RFQ), will be described. Upgrade measures in ALPI to improve beam transmission and final energy, and handle low-intensity RIB will be explained, with the aim of increasing transmission to T > 90%, Ef by ~ 20%, reaching 10 MeV/u for the reference beam 132Sn.

  2. NHWAVE: Consistent boundary conditions and turbulence modeling

    NASA Astrophysics Data System (ADS)

    Derakhti, Morteza; Kirby, James T.; Shi, Fengyan; Ma, Gangfeng

    2016-10-01

    Large-scale σ-coordinate ocean circulation models neglect the horizontal variation of σ in the calculation of stress terms and boundary conditions. Following this practice, the effects of surface and bottom slopes in the dynamic surface and bottom boundary conditions have been usually neglected in the available non-hydrostatic wave-resolving models using a terrain-following grid. In this paper, we derive consistent surface and bottom boundary conditions for the normal and tangential stress fields as well as a Neumann-type boundary condition for scalar fluxes. Further, we examine the role of surface slopes in the predicted near-surface velocity and turbulence fields in surface gravity waves. By comparing the predicted velocity field in a deep-water standing wave in a closed basin, we show that the consistent boundary conditions do not generate unphysical vorticity at the free surface, in contrast to commonly used, simplified stress boundary conditions developed by ignoring all contributions except vertical shear in the transformation of stress terms. In addition, it is shown that the consistent boundary conditions significantly improve predicted wave shape, velocity and turbulence fields in regular surf zone breaking waves, compared with the simplified case. A more extensive model-data comparison of various breaking wave properties in different types of surface breaking waves is presented in companion papers (Derakhti et al., 2016a,b).

  3. Toward consistent snapshot of the digitized battlefield

    NASA Astrophysics Data System (ADS)

    Sarkar, Susanta P.; Richardson, Paul; Sieh, Larry

    1999-07-01

    A battlefield can be viewed as a collection of entities, enemy and friendly, during combat, each entity scans its surrounding with local sensors to be aware of the current situation. Through digitation of the battlefield, it is possible to share this locally sensed information among all the friendly entities. Significant war-fighting advantages can be realized, if this shared information is consistent. During one of the soldier-in-the-loop simulation exercises invovling ground-based enemy and friendly entities, it was found that achieving consistent snapshot at each friendly node is not a trivial problem. A few contributing factors are: suitable method for combining individual perspective to a global one, mode of communication, movement of all entities, different local perspective of each entity, sensor calibration, fault, and clock synchronization. At the US Army VETRONICS Technology Center, we are in the process of developing a family of algorithms capable of obtaining a consistent global picture invovling one of the critical properties, ground position of entities. In the first stage we have established that for point to point communicating entities, a vector clock based scheme uses fewer number of messages and arrives at the global picture earlier. However, this result does not scale to broadcast situations.

  4. Bayesian AVO inversion with consistent angle parameters

    NASA Astrophysics Data System (ADS)

    Li, Chao; Zhang, Jinmiao; Zhu, Zhenyu

    2017-04-01

    Amplitude versus offset (AVO) inversion has been extensively used in seismic exploration. Many different elastic parameters can be inverted by incorporating corresponding reflection coefficient approximations. Although efforts have been made to improve the accuracy of AVO inversions for years, there is still one problem that has long been ignored. In most methods, the angle in the approximation and the angle used in seismic angle gather extractions are not the same one. This inconsistency leads to inaccurate inversion results. In this paper, a Bayesian AVO inversion method with consistent angles is proposed to solve the problem and improve inversion accuracy. Firstly, a linearized P-wave reflection coefficient approximation with consistent angles is derived based on angle replacements. The equivalent form of the approximation in terms moduli and density is derived so that moduli can be inverted for reservoir characterization. Then, by convoluting it with seismic wavelets as the forward solver, a probabilistic prestack seismic inversion method with consistent angles is presented in a Bayesian scheme. The synthetic test proves that the accuracy of this method is higher than the traditional one. The real data example shows that the inversion result fits better with well log interpretation data, which verifies the feasibility of the proposed method.

  5. CMB lens sample covariance and consistency relations

    NASA Astrophysics Data System (ADS)

    Motloch, Pavel; Hu, Wayne; Benoit-Lévy, Aurélien

    2017-02-01

    Gravitational lensing information from the two and higher point statistics of the cosmic microwave background (CMB) temperature and polarization fields are intrinsically correlated because they are lensed by the same realization of structure between last scattering and observation. Using an analytic model for lens sample covariance, we show that there is one mode, separately measurable in the lensed CMB power spectra and lensing reconstruction, that carries most of this correlation. Once these measurements become lens sample variance dominated, this mode should provide a useful consistency check between the observables that is largely free of sampling and cosmological parameter errors. Violations of consistency could indicate systematic errors in the data and lens reconstruction or new physics at last scattering, any of which could bias cosmological inferences and delensing for gravitational waves. A second mode provides a weaker consistency check for a spatially flat universe. Our analysis isolates the additional information supplied by lensing in a model-independent manner but is also useful for understanding and forecasting CMB cosmological parameter errors in the extended Λ cold dark matter parameter space of dark energy, curvature, and massive neutrinos. We introduce and test a simple but accurate forecasting technique for this purpose that neither double counts lensing information nor neglects lensing in the observables.

  6. Ions beams and ferroelectric plasma sources

    NASA Astrophysics Data System (ADS)

    Stepanov, Anton

    Near-perfect space-charge neutralization is required for the transverse compression of high perveance ion beams for ion-beam-driven warm dense matter experiments, such as the Neutralized Drift Compression eXperiment (NDCX). Neutralization can be accomplished by introducing a plasma in the beam path, which provides free electrons that compensate the positive space charge of the ion beam. In this thesis, charge neutralization of a 40 keV, perveance-dominated Ar+ beam by a Ferroelectric Plasma Source (FEPS) is investigated. First, the parameters of the ion beam, such as divergence due to the extraction optics, charge neutralization fraction, and emittance were measured. The ion beam was propagated through the FEPS plasma, and the effects of charge neutralization were inferred from time-resolved measurements of the transverse beam profile. In addition, the dependence of FEPS plasma parameters on the configuration of the driving pulser circuit was studied to optimize pulser design. An ion accelerator was constructed that produced a 30-50 keV Ar + beam with pulse duration <300 mus and dimensionless perveance Q up to 8 x 10-4. Transverse profile measurements 33 cm downstream of the ion source showed that the dependence of beam radius on Q was consistent with space charge expansion. It was concluded that the beam was perveance-dominated with a charge neutralization fraction of approximately zero in the absence of neutralizing plasma. Since beam expansion occurred primarily due to space charge, the decrease in effective perveance due to neutralization by FEPS plasma can be inferred from the reduction in beam radius. Results on propagation of the ion beam through FEPS plasma demonstrate that after the FEPS is triggered, the beam radius decreases to its neutralized value in about 5 mus. The duration of neutralization was about 10 mus at a charging voltage VFEPS = 5.5 kV and 35 mus at VFEPS = 6.5 kV. With VFEPS = 6.5 kV, the transverse current density profile 33 cm downstream

  7. MINER{nu}A Test Beam Commissioning

    SciTech Connect

    Higuera, A.; Castorena, J.; Urrutia, Z.; Felix, J.; Zavala, G.

    2009-12-17

    MINER{nu}A Main INjector ExpeRiment {nu}-A is a high-statistic neutrino scattering experiment that will ran in the NuMI Beam Hall at Fermilab. To calibrate the energy response of the MINER{nu}A detector, a beamline is being designed for the MINER{nu}A Test Beam Detector (TBD). The TBD is a replica of the full MINER{nu}A detector at small scale for calibration studies of the main detector. The beamline design consists of the following parts: a copper target, used to generate tertiaries from an incoming secondary beam; a steel collimator for tertiaries, which also serves as a dump for the incoming beam; a time of fight system (scintillator planes); four wire chambers, for angle measurements and tracking; and two dipole magnets, used as an spectrometer. During last October, the first commissioning run of the MINER{nu}A Test Beam took place in the Meson Test Beam Facility at Fermilab. We commissioned the target and collimator of the new tertiary beamline.

  8. Consistency of color representation in smart phones.

    PubMed

    Dain, Stephen J; Kwan, Benjamin; Wong, Leslie

    2016-03-01

    One of the barriers to the construction of consistent computer-based color vision tests has been the variety of monitors and computers. Consistency of color on a variety of screens has necessitated calibration of each setup individually. Color vision examination with a carefully controlled display has, as a consequence, been a laboratory rather than a clinical activity. Inevitably, smart phones have become a vehicle for color vision tests. They have the advantage that the processor and screen are associated and there are fewer models of smart phones than permutations of computers and monitors. Colorimetric consistency of display within a model may be a given. It may extend across models from the same manufacturer but is unlikely to extend between manufacturers especially where technologies vary. In this study, we measured the same set of colors in a JPEG file displayed on 11 samples of each of four models of smart phone (iPhone 4s, iPhone5, Samsung Galaxy S3, and Samsung Galaxy S4) using a Photo Research PR-730. The iPhones are white LED backlit LCD and the Samsung are OLEDs. The color gamut varies between models and comparison with sRGB space shows 61%, 85%, 117%, and 110%, respectively. The iPhones differ markedly from the Samsungs and from one another. This indicates that model-specific color lookup tables will be needed. Within each model, the primaries were quite consistent (despite the age of phone varying within each sample). The worst case in each model was the blue primary; the 95th percentile limits in the v' coordinate were ±0.008 for the iPhone 4 and ±0.004 for the other three models. The u'v' variation in white points was ±0.004 for the iPhone4 and ±0.002 for the others, although the spread of white points between models was u'v'±0.007. The differences are essentially the same for primaries at low luminance. The variation of colors intermediate between the primaries (e.g., red-purple, orange) mirror the variation in the primaries. The variation in

  9. Diffraction of a Laser Beam.

    ERIC Educational Resources Information Center

    Jodoin, Ronald E.

    1979-01-01

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

  10. Stability of cooled beams

    NASA Astrophysics Data System (ADS)

    Bosser, J.; Carli, C.; Chanel, M.; Madsen, N.; Maury, S.; Möhl, D.; Tranquille, G.

    2000-02-01

    Because of their high density together with extremely small spreads in betatron frequency and momentum, cooled beams are very vulnerable to incoherent and coherent space-charge effects and instabilities. Moreover, the cooling system itself, i.e. the electron beam in the case of e-cooling, presents large linear and non-linear "impedances" to the circulating ion beam, in addition to the usual beam-environment coupling impedances of the storage ring. Beam blow-up and losses, attributed to such effects, have been observed in virtually all the existing electron cooling rings. The adverse effects seem to be more pronounced in those rings, like CELSIUS, that are equipped with a cooler capable of reaching the presently highest energy (100-300 keV electrons corresponding to 180-560 MeV protons). The stability conditions will be revisited with emphasis on the experience gained at LEAR. It will be argued that for all present coolers, three conditions are necessary (although probably not sufficient) for the stability of intense cold beams: (i) operation below transition energy, (ii) active damping to counteract coherent instability, and (iii) careful control of the e-beam neutralisation. An extrapolation to the future "medium energy coolers", planned to work for (anti)protons of several GeV, will also be attempted.

  11. Evaluating Temporal Consistency in Marine Biodiversity Hotspots

    PubMed Central

    Barner, Allison K.; Benkwitt, Cassandra E.; Boersma, Kate S.; Cerny-Chipman, Elizabeth B.; Ingeman, Kurt E.; Kindinger, Tye L.; Lindsley, Amy J.; Nelson, Jake; Reimer, Jessica N.; Rowe, Jennifer C.; Shen, Chenchen; Thompson, Kevin A.; Heppell, Selina S.

    2015-01-01

    With the ongoing crisis of biodiversity loss and limited resources for conservation, the concept of biodiversity hotspots has been useful in determining conservation priority areas. However, there has been limited research into how temporal variability in biodiversity may influence conservation area prioritization. To address this information gap, we present an approach to evaluate the temporal consistency of biodiversity hotspots in large marine ecosystems. Using a large scale, public monitoring dataset collected over an eight year period off the US Pacific Coast, we developed a methodological approach for avoiding biases associated with hotspot delineation. We aggregated benthic fish species data from research trawls and calculated mean hotspot thresholds for fish species richness and Shannon’s diversity indices over the eight year dataset. We used a spatial frequency distribution method to assign hotspot designations to the grid cells annually. We found no areas containing consistently high biodiversity through the entire study period based on the mean thresholds, and no grid cell was designated as a hotspot for greater than 50% of the time-series. To test if our approach was sensitive to sampling effort and the geographic extent of the survey, we followed a similar routine for the northern region of the survey area. Our finding of low consistency in benthic fish biodiversity hotspots over time was upheld, regardless of biodiversity metric used, whether thresholds were calculated per year or across all years, or the spatial extent for which we calculated thresholds and identified hotspots. Our results suggest that static measures of benthic fish biodiversity off the US West Coast are insufficient for identification of hotspots and that long-term data are required to appropriately identify patterns of high temporal variability in biodiversity for these highly mobile taxa. Given that ecological communities are responding to a changing climate and other

  12. Evaluating Temporal Consistency in Marine Biodiversity Hotspots.

    PubMed

    Piacenza, Susan E; Thurman, Lindsey L; Barner, Allison K; Benkwitt, Cassandra E; Boersma, Kate S; Cerny-Chipman, Elizabeth B; Ingeman, Kurt E; Kindinger, Tye L; Lindsley, Amy J; Nelson, Jake; Reimer, Jessica N; Rowe, Jennifer C; Shen, Chenchen; Thompson, Kevin A; Heppell, Selina S

    2015-01-01

    With the ongoing crisis of biodiversity loss and limited resources for conservation, the concept of biodiversity hotspots has been useful in determining conservation priority areas. However, there has been limited research into how temporal variability in biodiversity may influence conservation area prioritization. To address this information gap, we present an approach to evaluate the temporal consistency of biodiversity hotspots in large marine ecosystems. Using a large scale, public monitoring dataset collected over an eight year period off the US Pacific Coast, we developed a methodological approach for avoiding biases associated with hotspot delineation. We aggregated benthic fish species data from research trawls and calculated mean hotspot thresholds for fish species richness and Shannon's diversity indices over the eight year dataset. We used a spatial frequency distribution method to assign hotspot designations to the grid cells annually. We found no areas containing consistently high biodiversity through the entire study period based on the mean thresholds, and no grid cell was designated as a hotspot for greater than 50% of the time-series. To test if our approach was sensitive to sampling effort and the geographic extent of the survey, we followed a similar routine for the northern region of the survey area. Our finding of low consistency in benthic fish biodiversity hotspots over time was upheld, regardless of biodiversity metric used, whether thresholds were calculated per year or across all years, or the spatial extent for which we calculated thresholds and identified hotspots. Our results suggest that static measures of benthic fish biodiversity off the US West Coast are insufficient for identification of hotspots and that long-term data are required to appropriately identify patterns of high temporal variability in biodiversity for these highly mobile taxa. Given that ecological communities are responding to a changing climate and other

  13. CRYSTALLINE BEAMS AT HIGH ENERGIES.

    SciTech Connect

    WEI, J.; OKAMOTO, H.; YURI, Y.; SESSLER, A.; MACHIDA, S.

    2006-06-23

    Previously it was shown that by crystallizing each of the two counter-circulating beams, a much larger beam-beam tune shift can be tolerated during the beam-beam collisions; thus a higher luminosity can be reached for colliding beams [1]. On the other hand, crystalline beams can only be formed at energies below the transition energy ({gamma}{sub T}) of the accelerators [2]. In this paper, we investigate the formation of crystals in a high-{gamma}{sub T} lattice that also satisfies the maintenance condition for a crystalline beam [3].

  14. Information, Consistent Estimation and Dynamic System Identification.

    DTIC Science & Technology

    1976-11-01

    Data fnfetd) --t 90gg- I .No-ýnber 1976 Report ESL-R-718 INFORMATION, CONSISTENT ESTIMATION AND DYNAMIC SYSTEM IDENTIFICATION by Yoram Bara W This report...8217 • L .. +• " -’ .... .. .... .. .. ’• ’• "- ’"l ’"ll ~ll~ 2 l 1NFURMAT10N~, CUNSISTENT LST1IMATION JaN DYiNAMIC SYSTEM IDENTIFICATION byI Yoramn...one? 1. particular problem of considerable practical significance is that qI -3-3 of dynamic system identification . The situation described above, and

  15. Surface consistent finite frequency phase corrections

    NASA Astrophysics Data System (ADS)

    Kimman, W. P.

    2016-07-01

    Static time-delay corrections are frequency independent and ignore velocity variations away from the assumed vertical ray path through the subsurface. There is therefore a clear potential for improvement if the finite frequency nature of wave propagation can be properly accounted for. Such a method is presented here based on the Born approximation, the assumption of surface consistency and the misfit of instantaneous phase. The concept of instantaneous phase lends itself very well for sweep-like signals, hence these are the focus of this study. Analytical sensitivity kernels are derived that accurately predict frequency-dependent phase shifts due to P-wave anomalies in the near surface. They are quick to compute and robust near the source and receivers. An additional correction is presented that re-introduces the nonlinear relation between model perturbation and phase delay, which becomes relevant for stronger velocity anomalies. The phase shift as function of frequency is a slowly varying signal, its computation therefore does not require fine sampling even for broad-band sweeps. The kernels reveal interesting features of the sensitivity of seismic arrivals to the near surface: small anomalies can have a relative large impact resulting from the medium field term that is dominant near the source and receivers. Furthermore, even simple velocity anomalies can produce a distinct frequency-dependent phase behaviour. Unlike statics, the predicted phase corrections are smooth in space. Verification with spectral element simulations shows an excellent match for the predicted phase shifts over the entire seismic frequency band. Applying the phase shift to the reference sweep corrects for wavelet distortion, making the technique akin to surface consistent deconvolution, even though no division in the spectral domain is involved. As long as multiple scattering is mild, surface consistent finite frequency phase corrections outperform traditional statics for moderately large

  16. Consistency relations for the conformal mechanism

    SciTech Connect

    Creminelli, Paolo; Joyce, Austin; Khoury, Justin; Simonović, Marko E-mail: joyceau@sas.upenn.edu E-mail: marko.simonovic@sissa.it

    2013-04-01

    We systematically derive the consistency relations associated to the non-linearly realized symmetries of theories with spontaneously broken conformal symmetry but with a linearly-realized de Sitter subalgebra. These identities relate (N+1)-point correlation functions with a soft external Goldstone to N-point functions. These relations have direct implications for the recently proposed conformal mechanism for generating density perturbations in the early universe. We study the observational consequences, in particular a novel one-loop contribution to the four-point function, relevant for the stochastic scale-dependent bias and CMB μ-distortion.

  17. Consistent Predictions of Future Forest Mortality

    NASA Astrophysics Data System (ADS)

    McDowell, N. G.

    2014-12-01

    We examined empirical and model based estimates of current and future forest mortality of conifers in the northern hemisphere. Consistent water potential thresholds were found that resulted in mortality of our case study species, pinon pine and one-seed juniper. Extending these results with IPCC climate scenarios suggests that most existing trees in this region (SW USA) will be dead by 2050. Further, independent estimates of future mortality for the entire coniferous biome suggest widespread mortality by 2100. The validity and assumptions and implications of these results are discussed.

  18. Planck 2013 results. XXXI. Consistency of the Planck data

    NASA Astrophysics Data System (ADS)

    Planck Collaboration; Ade, P. A. R.; Arnaud, M.; Ashdown, M.; Aumont, J.; Baccigalupi, C.; Banday, A. J.; Barreiro, R. B.; Battaner, E.; Benabed, K.; Benoit-Lévy, A.; Bernard, J.-P.; Bersanelli, M.; Bielewicz, P.; Bond, J. R.; Borrill, J.; Bouchet, F. R.; Burigana, C.; Cardoso, J.-F.; Catalano, A.; Challinor, A.; Chamballu, A.; Chiang, H. C.; Christensen, P. R.; Clements, D. L.; Colombi, S.; Colombo, L. P. L.; Couchot, F.; Coulais, A.; Crill, B. P.; Curto, A.; Cuttaia, F.; Danese, L.; Davies, R. D.; Davis, R. J.; de Bernardis, P.; de Rosa, A.; de Zotti, G.; Delabrouille, J.; Désert, F.-X.; Dickinson, C.; Diego, J. M.; Dole, H.; Donzelli, S.; Doré, O.; Douspis, M.; Dupac, X.; Enßlin, T. A.; Eriksen, H. K.; Finelli, F.; Forni, O.; Frailis, M.; Fraisse, A. A.; Franceschi, E.; Galeotta, S.; Ganga, K.; Giard, M.; González-Nuevo, J.; Górski, K. M.; Gratton, S.; Gregorio, A.; Gruppuso, A.; Gudmundsson, J. E.; Hansen, F. K.; Hanson, D.; Harrison, D. L.; Henrot-Versillé, S.; Herranz, D.; Hildebrandt, S. R.; Hivon, E.; Hobson, M.; Holmes, W. A.; Hornstrup, A.; Hovest, W.; Huffenberger, K. M.; Jaffe, A. H.; Jaffe, T. R.; Jones, W. C.; Keihänen, E.; Keskitalo, R.; Knoche, J.; Kunz, M.; Kurki-Suonio, H.; Lagache, G.; Lähteenmäki, A.; Lamarre, J.-M.; Lasenby, A.; Lawrence, C. R.; Leonardi, R.; León-Tavares, J.; Lesgourgues, J.; Liguori, M.; Lilje, P. B.; Linden-Vørnle, M.; López-Caniego, M.; Lubin, P. M.; Macías-Pérez, J. F.; Maino, D.; Mandolesi, N.; Maris, M.; Martin, P. G.; Martínez-González, E.; Masi, S.; Matarrese, S.; Mazzotta, P.; Meinhold, P. R.; Melchiorri, A.; Mendes, L.; Mennella, A.; Migliaccio, M.; Mitra, S.; Miville-Deschênes, M.-A.; Moneti, A.; Montier, L.; Morgante, G.; Mortlock, D.; Moss, A.; Munshi, D.; Murphy, J. A.; Naselsky, P.; Nati, F.; Natoli, P.; Nørgaard-Nielsen, H. U.; Noviello, F.; Novikov, D.; Novikov, I.; Oxborrow, C. A.; Pagano, L.; Pajot, F.; Paoletti, D.; Partridge, B.; Pasian, F.; Patanchon, G.; Pearson, D.; Pearson, T. J.; Perdereau, O.; Perrotta, F.; Piacentini, F.; Piat, M.; Pierpaoli, E.; Pietrobon, D.; Plaszczynski, S.; Pointecouteau, E.; Polenta, G.; Ponthieu, N.; Popa, L.; Pratt, G. W.; Prunet, S.; Puget, J.-L.; Rachen, J. P.; Reinecke, M.; Remazeilles, M.; Renault, C.; Ricciardi, S.; Ristorcelli, I.; Rocha, G.; Roudier, G.; Rubiño-Martín, J. A.; Rusholme, B.; Sandri, M.; Scott, D.; Stolyarov, V.; Sudiwala, R.; Sutton, D.; Suur-Uski, A.-S.; Sygnet, J.-F.; Tauber, J. A.; Terenzi, L.; Toffolatti, L.; Tomasi, M.; Tristram, M.; Tucci, M.; Valenziano, L.; Valiviita, J.; Van Tent, B.; Vielva, P.; Villa, F.; Wade, L. A.; Wandelt, B. D.; Wehus, I. K.; White, S. D. M.; Yvon, D.; Zacchei, A.; Zonca, A.

    2014-11-01

    The Planck design and scanning strategy provide many levels of redundancy that can be exploited to provide tests of internal consistency. One of the most important is the comparison of the 70 GHz (amplifier) and 100 GHz (bolometer) channels. Based on different instrument technologies, with feeds located differently in the focal plane, analysed independently by different teams using different software, and near the minimum of diffuse foreground emission, these channels are in effect two different experiments. The 143 GHz channel has the lowest noise level on Planck, and is near the minimum of unresolved foreground emission. In this paper, we analyse the level of consistency achieved in the 2013 Planck data. We concentrate on comparisons between the 70, 100, and 143 GHz channel maps and power spectra, particularly over the angular scales of the first and second acoustic peaks, on maps masked for diffuse Galactic emission and for strong unresolved sources. Difference maps covering angular scales from 8° to 15' are consistent with noise, and show no evidence of cosmic microwave background structure. Including small but important corrections for unresolved-source residuals, we demonstrate agreement (measured by deviation of the ratio from unity) between 70 and 100 GHz power spectra averaged over 70 ≤ ℓ ≤ 390 at the 0.8% level, and agreement between 143 and 100 GHz power spectra of 0.4% over the same ℓ range. These values are within and consistent with the overall uncertainties in calibration given in the Planck 2013 results. We also present results based on the 2013 likelihood analysis showing consistency at the 0.35% between the 100, 143, and 217 GHz power spectra. We analyse calibration procedures and beams to determine what fraction of these differences can be accounted for by known approximations or systematicerrors that could be controlled even better in the future, reducing uncertainties still further. Several possible small improvements are described

  19. Beam distributions beyond RMS

    NASA Astrophysics Data System (ADS)

    Decker, F.-J.

    1995-05-01

    The beam is often represented only by its position (mean) and the width (rms=root mean squared) of its distribution. To achieve these beam parameters in a noisy condition with high backgrounds, a Gaussian distribution with offset (4 parameters) is fitted to the measured beam distribution. This gives a very robust answer and is not very sensitive to background subtraction techniques. To get higher moments of the distribution, like skew or kurtosis, a fitting function with one or two more parameters is desired which would model the higher moments. In this paper we will concentrate on an Asymmetric Gaussian and a Super Gaussian function that will give something like the skew and the kurtosis of the distribution. This information is used to quantify special beam distribution. Some are unwanted like beam tails (skew) from transverse wakefields, higher order dispersive aberrations or potential well distortion in a damping ring. A negative kurtosis of a beam distribution describes a more rectangular, compact shape like with an over-compressed beam in z or a closed to double-horned energy distribution, while a positive kurtosis looks more like a ``Christmas tree'' and can quantify a beam mismatch after filamentation. Besides the advantages of the quantification, there are some distributions which need a further investigation like long flat tails which create background particles in a detector. In particle simulations on the other hand a simple rms number might grossly overestimate the effective size (e.g. for producing luminosity) due to a few particles which are far away from the core. This can reduce the practical gain of a big theoretical improvement in the beam size.

  20. Beam distributions beyond RMS

    NASA Astrophysics Data System (ADS)

    Decker, F. J.

    1994-09-01

    The beam is often represented only by its position (mean) and the width (rms = root mean squared) of its distribution. To achieve these beam parameters in a noisy condition with high backgrounds, a Gaussian distribution with offset (4 parameters) is fitted to the measured beam distribution. This gives a very robust answer and is not very sensitive to background subtraction techniques. To get higher moments of the distribution, like skew or kurtosis, a fitting function with one or two more parameters is desired which would model the higher moments. In this paper we will concentrate on an Asymmetric Gaussian and a Super Gaussian function that will give something like the skew and the kurtosis of the distribution. This information is used to quantify special beam distribution. Some are unwanted like beam tails (skew) from transverse wakefields, higher order dispersive aberrations or potential well distortion in a damping ring. A negative kurtosis of a beam distribution describes a more rectangular, compact shape like with an over-compressed beam in z or a closed to double-homed energy distribution, while a positive kurtosis looks more like a 'Christmas tree' and can quantify a beam mismatch after filamentation. Besides the advantages of the quantification, there are some distributions which need a further investigation like long flat tails which create background particles in a detector. In particle simulations on the other hand a simple rms number might grossly overestimate the effective size (e.g. for producing luminosity) due to a few particles which are far away from the core. This can reduce the practical gain of a big theoretical improvement in the beam size.

  1. Beam distributions beyond RMS

    SciTech Connect

    Decker, F.J.

    1994-09-01

    The beam is often represented only by its position (mean) and the width (rms = root mean squared) of its distribution. To achieve these beam parameters in a noisy condition with high backgrounds, a Gaussian distribution with offset (4 parmeters) is fitted to the measured beam distribution. This gives a very robust answer and is not very sensitive to background subtraction techniques. To get higher moments of the distribution, like skew or kurtosis, a fitting function with one or two more parameters is desired which would model the higher moments. In this paper we will concentrate on an Asymmetric Gaussian and a Super Gaussian function that will give something like the skew and the kurtosis of the distribution. This information is used to quantify special beam distribution. Some are unwanted like beam tails (skew) from transverse wakefields, higher order dispersive aberrations or potential well distortion in a damping ring. A negative kurtosis of a beam distribution describes a more rectangular, compact shape like with an over-compressed beam in z or a closed to double-homed energy distribution, while a positive kurtosis looks more like a ``Christmas tree`` and can quantify a beam mismatch after filamentation. Besides the advantages of the quantification, there are some distributions which need a further investigation like long flat tails which create background particles in a detector. In particle simulations on the other hand a simple rms number might grossly overestimate the effective size (e.g. for producing luminosity) due to a few particles which are far away from the core. This can reduce the practical gain of a big theoretical improvement in the beam size.

  2. Simulation of ion beam injection and extraction in an EBIS

    SciTech Connect

    Zhao, L. Kim, J. S.

    2016-02-15

    An example simulation of Au+ charge breeding using FAR-TECH’s integrated EBIS (electron beam ion source) modeling toolset is presented with the emphasis on ion beam injection and extraction. The trajectories of injected ions are calculated with PBGUNS (particle beam gun simulation) self-consistently by including the space charges from both ions and electrons. The ion beam, starting with initial conditions within the 100% acceptance of the electron beam, is then tracked by EBIS-PIC (particle-in-cell EBIS simulation code). In the trap, the evolution of the ion charge state distribution is estimated by charge state estimator. The extraction of charge bred ions is simulated with PBGUNS. The simulations of the ion injections show significant ion space charge effects on beam capture efficiency and the ionization efficiency.

  3. On the mechanics of thin-walled laminated composite beams

    NASA Astrophysics Data System (ADS)

    Barbero, Ever J.; Lopez-Anido, Roberto; Davalos, Julio F.

    1993-01-01

    A formal engineering approach of the mechanics of thin-walled laminated beams based on kinematic assumptions consistent with Timoshenko beam theory is presented. Thin-walled composite beams with open or closed cross section subjected to bending and axial load are considered. A variational formulation is employed to obtain a comprehensive description of the structural response. Beam stiffness coefficients, which account for the cross section geometry and for the material anisotropy, are obtained. An explicit expression for the static shear correction factor of thin-walled composite beams is derived from energy equivalence. A numerical example involving a laminated I-beam is used to used to demonstrate the capability of the model for predicting displacements and ply stresses.

  4. Electron cyclotron beam measurement system in the Large Helical Device

    SciTech Connect

    Kamio, S. Takahashi, H.; Kubo, S.; Shimozuma, T.; Yoshimura, Y.; Igami, H.; Ito, S.; Kobayashi, S.; Mizuno, Y.; Okada, K.; Osakabe, M.; Mutoh, T.

    2014-11-15

    In order to evaluate the electron cyclotron (EC) heating power inside the Large Helical Device vacuum vessel and to investigate the physics of the interaction between the EC beam and the plasma, a direct measurement system for the EC beam transmitted through the plasma column was developed. The system consists of an EC beam target plate, which is made of isotropic graphite and faces against the EC beam through the plasma, and an IR camera for measuring the target plate temperature increase by the transmitted EC beam. This system is applicable to the high magnetic field (up to 2.75 T) and plasma density (up to 0.8 × 10{sup 19} m{sup −3}). This system successfully evaluated the transmitted EC beam profile and the refraction.

  5. VideoBeam portable laser communicator

    NASA Astrophysics Data System (ADS)

    Mecherle, G. Stephen; Holcomb, Terry L.

    1999-01-01

    A VideoBeamTM portable laser communicator has been developed which provides full duplex communication links consisting of high quality analog video and stereo audio. The 3.2-pound unit resembles a binocular-type form factor and has an operational range of over two miles (clear air) with excellent jam-resistance and low probability of interception characteristics. The VideoBeamTM unit is ideally suited for numerous military scenarios, surveillance/espionage, industrial precious mineral exploration, and campus video teleconferencing applications.

  6. ATA diagnostic beam dump conceptual design

    SciTech Connect

    Not Available

    1981-09-01

    A diagnostic beam dump, able to withstand 72,000 pulses (10 kA, 50 MeV/pulse) per shift was designed and analyzed. The analysis shows that the conceptual beam dump design consisting of 80 vitreous carbon plate-foam elements is able to withstand the thermal and mechanical stresses generated. X-rays produced by bremsstrahlung are absorbed by a three element copper plate-foam x-ray absorber. Cooling between bursts of electron pulses is provided by pressurized helium.

  7. Beam alignment test for therapy accelerators

    SciTech Connect

    Lutz, W.R.; Larsen, R.D.; Bjarngard, B.D.

    1981-12-01

    Beam spot displacement, collimator asymmetry, and movement of either collimator or gantry rotational axis can cause misalignment of the X ray beam from a therapy accelerator. A test method, sensitive to all the above problems, consists of double-exposing a film, located at the isocenter, for two gantry positions, 180/sup o/ apart. Opposite halves of the field are blocked for each exposure. A lateral shift of one half with respect to the other indicates the presence of one of the problems mentioned above. Additional tests are described, each of which is sensitive to only one of the problems and capable of quantifying the error.

  8. Beam alignment tests for therapy accelerators

    SciTech Connect

    Lutz, W.R.; Larsen, R.D.; Bjarngard, B.E.

    1981-12-01

    Beam spot displacement, collimator asymmetry, and movement of either collimator or gantry rotational axis can cause misalignment of the X ray beam from a therapy accelerator. A test method, sensitive to all the above problems, consists of double-exposing a film, located at the isocenter, for two gantry positions, 180/sup 0/ apart. Opposite halves of the field are blocked for each exposure. A lateral shift of one half with respect to the other indicates the presence of one of the problems mentioned above. Additional tests are described, each of which is sensitive to only one of the problems and capable of quantifying the error.

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

    SciTech Connect

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

    2009-02-01

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

  10. Design and performance of the pulsed positron beam at Chalmers University of Technology

    NASA Astrophysics Data System (ADS)

    Mileshina, L.; Nordlund, A.

    2009-09-01

    A slow monoenergetic pulsed positron beam at Chalmers University of Technology has been built. The system consists mainly of chopper, buncher and accelerator. The achieved positron energy range is in range between 230 eV and 15 keV. The FWHM of the beam resolution function is around 700 ps. The beam intensity is around 103 cps.

  11. Ion beam lithography system

    DOEpatents

    Leung, Ka-Ngo

    2005-08-02

    A maskless plasma-formed ion beam lithography tool provides for patterning of sub-50 nm features on large area flat or curved substrate surfaces. The system is very compact and does not require an accelerator column and electrostatic beam scanning components. The patterns are formed by switching beamlets on or off from a two electrode blanking system with the substrate being scanned mechanically in one dimension. This arrangement can provide a maskless nano-beam lithography tool for economic and high throughput processing.

  12. Ion beam accelerator system

    NASA Technical Reports Server (NTRS)

    Aston, Graeme (Inventor)

    1984-01-01

    A system is described that combines geometrical and electrostatic focusing to provide high ion extraction efficiency and good focusing of an accelerated ion beam. The apparatus includes a pair of curved extraction grids (16, 18) with multiple pairs of aligned holes positioned to direct a group of beamlets (20) along converging paths. The extraction grids are closely spaced and maintained at a moderate potential to efficiently extract beamlets of ions and allow them to combine into a single beam (14). An accelerator electrode device (22) downstream from the extraction grids, is at a much lower potential than the grids to accelerate the combined beam.

  13. Ion beam accelerator system

    NASA Technical Reports Server (NTRS)

    Aston, G. (Inventor)

    1981-01-01

    A system is described that combines geometrical and electrostatic focusing to provide high ion extraction efficiency and good focusing of an accelerated ion beam. The apparatus includes a pair of curved extraction grids with multiple pairs of aligned holes positioned to direct a group of beamlets along converging paths. The extraction grids are closely spaced and maintained at a moderate potential to efficiently extract beamlets of ions and allow them to combine into a single beam. An accelerator electrode device downstream from the extraction grids is at a much lower potential than the grids to accelerate the combined beam. The application of the system to ion implantation is mentioned.

  14. Beam Purification by Photodetachment

    SciTech Connect

    Liu, Yuan; Beene, James R; Havener, Charles C; Galindo-Uribarri, Alfredo {nmn}; Andersson, P.; Lindahl, A. O.; Hanstorp, D.; Forstner, Dr. Oliver; Gottwald, T.; Wendt, K.

    2012-01-01

    Ion beam purity is of crucial importance to many basic and applied studies. Selective photodetachment has been proposed to suppress unwanted species in negative ion beams while preserving the intensity of the species of interest. A highly efficient technique based on photodetachment in a gas-filled radio frequency quadrupole ion cooler has been demonstrated. In off-line experiments with stable ions, up to 104 times suppression of the isobar contaminants in a number of interesting radioactive negative ion beams has been demonstrated. For selected species, this technique promises experimental possibilities in studies on exotic nuclei, accelerator mass spectrometry, and fundamental properties of negative atomic and molecular ions.

  15. Ion beam thruster shield

    NASA Technical Reports Server (NTRS)

    Power, J. L. (Inventor)

    1976-01-01

    An ion thruster beam shield is provided that comprises a cylindrical housing that extends downstream from the ion thruster and a plurality of annular vanes which are spaced along the length of the housing, and extend inwardly from the interior wall of the housing. The shield intercepts and stops all charge exchange and beam ions, neutral propellant, and sputter products formed due to the interaction of beam and shield emanating from the ion thruster outside of a fixed conical angle from the thruster axis. Further, the shield prevents the sputter products formed during the operation of the engine from escaping the interior volume of the shield.

  16. Kinematically consistent models of viscoelastic stress evolution

    NASA Astrophysics Data System (ADS)

    DeVries, Phoebe M. R.; Meade, Brendan J.

    2016-05-01

    Following large earthquakes, coseismic stresses at the base of the seismogenic zone may induce rapid viscoelastic deformation in the lower crust and upper mantle. As stresses diffuse away from the primary slip surface in these lower layers, the magnitudes of stress at distant locations (>1 fault length away) may slowly increase. This stress relaxation process has been used to explain delayed earthquake triggering sequences like the 1992 Mw = 7.3 Landers and 1999 Mw = 7.1 Hector Mine earthquakes in California. However, a conceptual difficulty associated with these models is that the magnitudes of stresses asymptote to constant values over long time scales. This effect introduces persistent perturbations to the total stress field over many earthquake cycles. Here we present a kinematically consistent viscoelastic stress transfer model where the total perturbation to the stress field at the end of the earthquake cycle is zero everywhere. With kinematically consistent models, hypotheses about the potential likelihood of viscoelastically triggered earthquakes may be based on the timing of stress maxima, rather than on any arbitrary or empirically constrained stress thresholds. Based on these models, we infer that earthquakes triggered by viscoelastic earthquake cycle effects may be most likely to occur during the first 50% of the earthquake cycle regardless of the assumed long-term and transient viscosities.

  17. Consistent resolution of some relativistic quantum paradoxes

    SciTech Connect

    Griffiths, Robert B.

    2002-12-01

    A relativistic version of the (consistent or decoherent) histories approach to quantum theory is developed on the basis of earlier work by Hartle, and used to discuss relativistic forms of the paradoxes of spherical wave packet collapse, Bohm's formulation of the Einstein-Podolsky-Rosen paradox, and Hardy's paradox. It is argued that wave function collapse is not needed for introducing probabilities into relativistic quantum mechanics, and in any case should never be thought of as a physical process. Alternative approaches to stochastic time dependence can be used to construct a physical picture of the measurement process that is less misleading than collapse models. In particular, one can employ a coarse-grained but fully quantum-mechanical description in which particles move along trajectories, with behavior under Lorentz transformations the same as in classical relativistic physics, and detectors are triggered by particles reaching them along such trajectories. States entangled between spacelike separate regions are also legitimate quantum descriptions, and can be consistently handled by the formalism presented here. The paradoxes in question arise because of using modes of reasoning which, while correct for classical physics, are inconsistent with the mathematical structure of quantum theory, and are resolved (or tamed) by using a proper quantum analysis. In particular, there is no need to invoke, nor any evidence for, mysterious long-range superluminal influences, and thus no incompatibility, at least from this source, between relativity theory and quantum mechanics.

  18. Consistent mutational paths predict eukaryotic thermostability

    PubMed Central

    2013-01-01

    Background Proteomes of thermophilic prokaryotes have been instrumental in structural biology and successfully exploited in biotechnology, however many proteins required for eukaryotic cell function are absent from bacteria or archaea. With Chaetomium thermophilum, Thielavia terrestris and Thielavia heterothallica three genome sequences of thermophilic eukaryotes have been published. Results Studying the genomes and proteomes of these thermophilic fungi, we found common strategies of thermal adaptation across the different kingdoms of Life, including amino acid biases and a reduced genome size. A phylogenetics-guided comparison of thermophilic proteomes with those of other, mesophilic Sordariomycetes revealed consistent amino acid substitutions associated to thermophily that were also present in an independent lineage of thermophilic fungi. The most consistent pattern is the substitution of lysine by arginine, which we could find in almost all lineages but has not been extensively used in protein stability engineering. By exploiting mutational paths towards the thermophiles, we could predict particular amino acid residues in individual proteins that contribute to thermostability and validated some of them experimentally. By determining the three-dimensional structure of an exemplar protein from C. thermophilum (Arx1), we could also characterise the molecular consequences of some of these mutations. Conclusions The comparative analysis of these three genomes not only enhances our understanding of the evolution of thermophily, but also provides new ways to engineer protein stability. PMID:23305080

  19. Towards Consistent Models of Starless Cores

    NASA Astrophysics Data System (ADS)

    Shustov, Boris; Pavlyuchenkov, Yaroslav; Shematovich, Valery; Wiebe, Dimitri; Henning, Thomas; Semenov, Dimitri; Launhardt, Ralf

    The complete theory of the earliest stages of star formation can be developed only on the basis of self-consistent coupled dynamical and chemical models for the evolution of protostellar clouds. The models including multidimensional geometry ""full"" chemistry and 2D/3D radiation transfer still do not exist. We analyze limitations of the existing approaches and main directions of the model improvements: revision of chemical reaction data bases reduction of chemical reaction network reasonable choice of model geometry radiation transfer. The most important goal of modeling of the real objects is to reveal unambiguous signatures of their evolutionary status. Starless cores are believed to be compact objects at very early stages of star formation. We use our results on 1D self-consistent evolution of starless cores to illustrate problems of modeling and interpretation. Special attention is drawn to the radiation transfer problem. New 2D code URAN(IA) for simulation of radiation transfer in molecular lines was developed. This code was used to analyze spectra of starless cores L1544 and CB17. The deduced parameters of these cores are discussed.

  20. ASTM/NBS base stock consistency study

    SciTech Connect

    Frassa, K.A.

    1980-11-01

    This paper summarizes the scope of a cooperative ASTM/NBS program established in June 1979. The contemplated study will ascertain the batch-to-batch consistency of re-refined and virgin base stocks manufactured by various processes. For one year, approximately eight to ten different base stocks samples, will be obtained by NBS every two weeks. One set of bi-monthly samples will be forwarded to each participant, on a coded basis monthly. Seven to eight samples will be obtained from six different re-refining processes and two virgin oil samples from a similar manufacturing process. The participants will report their results on a monthly basis. The second set of samples will be retained by NBS for an interim monthly sample study, if required, based on data analysis. Each sample's properties will be evaluated using various physical tests, chemical tests, and bench tests. The total testing program should define the batch-to-batch base stock consistency short of engine testing.

  1. Direct design of laser-beam shapers, zoom-beam expanders, and combinations thereof

    NASA Astrophysics Data System (ADS)

    Duerr, Fabian; Thienpont, Hugo

    2016-10-01

    Laser sources have become indispensable for industrial materials processing applications like surface treatment, cutting or welding to name a few examples. Many of these applications pose different requirements on the delivered laser irradiance distribution. Some applications might not only favor a specific irradiance distribution (e.g. a at-top) but can additionally benefit from time-varying distributions. We present an overview of a recently developed design approach that allows direct calculation of virtually any refractive or reflective laser beam shaping system. The derived analytic solution is fully described by few initial parameters and does allow an increasingly accurate calculation of all optical surfaces. Unlike other existing direct design methods for laser beam shaping, there is almost no limitation in the number of surfaces that can be calculated with this approach. This is of particular importance for optical designs of dynamic systems such as variable optical beam expanders that require four (or more) optical surfaces. Besides conventional static beam shapers, we present direct designs of zoom beam expanders, and as a novelty, a class of dynamic systems that shape and expand the input beam simultaneously. Such dynamic zoom beam shapers consist of a minimal number of optical elements and provide a much more compact solution, yet achieving excellent overall optical performance throughout the full range of zoom positions.

  2. A driver linac for the Advanced Exotic Beam Laboratory : physics design and beam dynamics simulations.

    SciTech Connect

    Ostroumov, P. N.; Mustapha, B.; Nolen, J.; Physics

    2007-01-01

    The Advanced Exotic Beam Laboratory (AEBL) being developed at ANL consists of an 833 MV heavy-ion driver linac capable of producing uranium ions up to 200 MeV/u and protons to 580 MeV with 400 kW beam power. We have designed all accelerator components including a two charge state LEBT, an RFQ, a MEBT, a superconducting linac, a stripper station and chicane. We present the results of an optimized linac design and end-to-end simulations including machine errors and detailed beam loss analysis. The Advanced Exotic Beam Laboratory (AEBL) has been proposed at ANL as a reduced scale of the original Rare Isotope Accelerator (RIA) project with about half the cost but the same beam power. AEBL will address 90% or more of RIA physics but with reduced multi-users capabilities. The focus of this paper is the physics design and beam dynamics simulations of the AEBL driver linac. The reported results are for a multiple charge state U{sup 238} beam.

  3. Numerical study of neutron beam divergence in a beam-fusion scenario employing laser driven ions

    NASA Astrophysics Data System (ADS)

    Alejo, A.; Green, A.; Ahmed, H.; Robinson, A. P. L.; Cerchez, M.; Clarke, R.; Doria, D.; Dorkings, S.; Fernandez, J.; McKenna, P.; Mirfayzi, S. R.; Naughton, K.; Neely, D.; Norreys, P.; Peth, C.; Powell, H.; Ruiz, J. A.; Swain, J.; Willi, O.; Borghesi, M.; Kar, S.

    2016-09-01

    The most established route to create a laser-based neutron source is by employing laser accelerated, low atomic-number ions in fusion reactions. In addition to the high reaction cross-sections at moderate energies of the projectile ions, the anisotropy in neutron emission is another important feature of beam-fusion reactions. Using a simple numerical model based on neutron generation in a pitcher-catcher scenario, anisotropy in neutron emission was studied for the deuterium-deuterium fusion reaction. Simulation results are consistent with the narrow-divergence (∼ 70 ° full width at half maximum) neutron beam recently served in an experiment employing multi-MeV deuteron beams of narrow divergence (up to 30° FWHM, depending on the ion energy) accelerated by a sub-petawatt laser pulse from thin deuterated plastic foils via the Target Normal Sheath Acceleration mechanism. By varying the input ion beam parameters, simulations show that a further improvement in the neutron beam directionality (i.e. reduction in the beam divergence) can be obtained by increasing the projectile ion beam temperature and cut-off energy, as expected from interactions employing higher power lasers at upcoming facilities.

  4. Caution -- Beam Crossing Ahead

    SciTech Connect

    Barat, Kenneth L.

    2008-04-02

    There are times when a laser beam needs to cross between tables or even go from one room to another. This presents an interesting traffic-flow and safety challenge to both the laser safety officer and laser user. Fortunately it is a challenge that has several solutions But the simplest solution may not be the best one. For example, the simplest way to get a beam from one optical table to another is just to put a sturdy tube around it. That's a permanent solution, and it completely contains the laser beam. While this is laser safe, there can be egress issues if it blocks a walkway. One comment this author often hears is, 'We can just duck under the tube.' The fire marshal, as well as the laser safety officer, might have issues with this. Especially in the case of a darkened lab, a blocked walkway can present a hazard of its own. One good solution is to transport the beam from Point A to Point B through a fiberoptic cable, when that is possible. One should easily be able to run the fiber up and over any walkway or down through a conduit on the floor. An important concern often overlooked with fibers is a label at the termination end indicating disconnection may expose one to laser radiation. Suppose there's an experiment that is usually confined to a single optical table, but sometimes needs to expand to a second table. It's inconvenient to install a permanent tube between the tables, so some sort of temporary arrangement is desirable. I have often seen people casually lay a beam tube across support arms, and remove it when it's not needed. The problem with this approach is that there's no mechanism to prevent the beam from crossing if somebody's forgotten the tube, or if the tube gets knocked out of place. A better solution is a mechanism that only allows the beam to cross when the beam protection is in place. A swing shutter, or a guillotine and swing arm, are examples (Figures 1 and 2). Another alternative is a sensor, maybe a little microswitch, that activates a

  5. Physical and engineering aspect of carbon beam therapy

    NASA Astrophysics Data System (ADS)

    Kanai, Tatsuaki; Kanematsu, Nobuyuki; Minohara, Shinichi; Yusa, Ken; Urakabe, Eriko; Mizuno, Hideyuki; Iseki, Yasushi; Kanazawa, Mitsutaka; Kitagawa, Atsushi; Tomitani, Takehiro

    2003-08-01

    Conformal irradiation system of HIMAC has been up-graded for a clinical trial using a technique of a layer-stacking method. The system has been developed for localizing irradiation dose to target volume more effectively than the present irradiation dose. With dynamic control of the beam modifying devices, a pair of wobbler magnets, and multileaf collimator and range shifter, during the irradiation, more conformal radiotherapy can be achieved. The system, which has to be adequately safe for patient irradiations, was constructed and tested from a viewpoint of safety and the quality of the dose localization realized. A secondary beam line has been constructed for use of radioactive beam in heavy-ion radiotherapy. Spot scanning method has been adapted for the beam delivery system of the radioactive beam. Dose distributions of the spot beam were measured and analyzed taking into account of aberration of the beam optics. Distributions of the stopped positron-emitter beam can be observed by PET. Pencil beam of the positron-emitter, about 1 mm size, can also be used for measurements ranges of the test beam in patients using positron camera. The positron camera, consisting of a pair of Anger-type scintillation detectors, has been developed for this verification before treatment. Wash-out effect of the positron-emitter was examined using the positron camera installed. In this report, present status of the HIMAC irradiation system is described in detail.

  6. Physical and engineering aspect of carbon beam therapy

    SciTech Connect

    Kanai, Tatsuaki; Kanematsu, Nobuyuki; Minohara, Shinichi; Yusa, Ken; Urakabe, Eriko; Kanazawa, Mitsutaka; Kitagawa, Atsushi; Tomitani, Takehiro; Mizuno, Hideyuki; Iseki, Yasushi

    2003-08-26

    Conformal irradiation system of HIMAC has been up-graded for a clinical trial using a technique of a layer-stacking method. The system has been developed for localizing irradiation dose to target volume more effectively than the present irradiation dose. With dynamic control of the beam modifying devices, a pair of wobbler magnets, and multileaf collimator and range shifter, during the irradiation, more conformal radiotherapy can be achieved. The system, which has to be adequately safe for patient irradiations, was constructed and tested from a viewpoint of safety and the quality of the dose localization realized. A secondary beam line has been constructed for use of radioactive beam in heavy-ion radiotherapy. Spot scanning method has been adapted for the beam delivery system of the radioactive beam. Dose distributions of the spot beam were measured and analyzed taking into account of aberration of the beam optics. Distributions of the stopped positron-emitter beam can be observed by PET. Pencil beam of the positron-emitter, about 1 mm size, can also be used for measurements ranges of the test beam in patients using positron camera. The positron camera, consisting of a pair of Anger-type scintillation detectors, has been developed for this verification before treatment. Wash-out effect of the positron-emitter was examined using the positron camera installed. In this report, present status of the HIMAC irradiation system is described in detail.

  7. Beam conditioner for free electron lasers and synchrotrons

    DOEpatents

    Liu, H.; Neil, G.R.

    1998-09-08

    A focused optical has been used to introduce an optical pulse, or electromagnetic wave, collinear with the electron beam in a free electron laser or synchrotron thereby adding an axial field component that accelerates the electrons on the radial outside of the distribution of electrons in the electron beam. This invention consists of using the axial electrical component of a TEM{sub 10} mode Gaussian beam in vacuum to condition the electron beam and speed up the outer electrons in the beam. The conditioning beam should possess about the same diameter as the electron beam. The beam waist of the conditioning wave must be located around the entrance of the undulator longitudinally to have a net energy exchange between the electrons in the outer part of the distribution and the conditioning wave owing to the natural divergence of a Gaussian beam. By accelerating the outer electrons, the outer and core electrons are caused to stay in phase. This increases the fraction of the electron beam energy that is converted to light thereby improving the efficiency of conversion of energy to light and therefore boosting the power output of the free electron laser and synchrotron. 4 figs.

  8. Beam conditioner for free electron lasers and synchrotrons

    DOEpatents

    Liu, Hongxiu; Neil, George R.

    1998-01-01

    A focused optical is been used to introduce an optical pulse, or electromagnetic wave, colinearly with the electron beam in a free electron laser or synchrotron thereby adding an axial field component that accelerates the electrons on the radial outside of the distribution of electrons in the electron beam. This invention consists of using the axial electrical component of a TEM.sub.10 mode Gaussian beam in vacuum to condition the electron beam and speed up the outer electrons in the beam. The conditioning beam should possess about the same diameter as the electron beam. The beam waist of the conditioning wave must be located around the entrance of the undulator longitudinally to have a net energy exchange between the electrons in the outer part of the distribution and the conditioning wave owing to the natural divergence of a Gaussian beam. By accelerating the outer electrons, the outer and core electrons are caused to stay in phase. This increases the fraction of the electron beam energy that is converted to light thereby improving the efficiency of conversion of energy to light and therefore boosting the power output of the free electron laser and synchrotron.

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

    NASA Technical Reports Server (NTRS)

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

    1978-01-01

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

  10. POCIT portable optical communicators: VideoBeam and EtherBeam

    NASA Astrophysics Data System (ADS)

    Mecherle, G. Stephen; Holcomb, Terry L.

    1999-12-01

    LDSC is developing the POCITTM (Portable Optical Communication Integrated Transceiver) family of products which now includes VideoBeamTM and the latest addition, EtherBeamTM. Each is a full duplex portable laser communicator: VideoBeamTM providing near-broadcast- quality analog video and stereo audio, and EtherBeamTM providing standard Ethernet connectivity. Each POCITTM transceiver consists of a 3.5-pound unit with a binocular- type form factor, which can be manually pointed, tripod- mounted or gyro-stabilized. Both units have an operational range of over two miles (clear air) with excellent jam- resistance and low probability of interception characteristics. The transmission wavelength of 1550 nm enables Class I eyesafe operation (ANSI, IEC). The POCITTM units are ideally suited for numerous miliary scenarios, surveillance/espionage, industrial precious mineral exploration, and campus video teleconferencing applications.

  11. Future e/sup +/e/sup -/ linear colliders and beam-beam effects

    SciTech Connect

    Wilson, P.B.

    1986-05-01

    Numerous concepts, ranging from conventional to highly exotic, hae been proposed for the acceleration of electrons and positrons to very high energies. For any such concept to be viable, it must be possible to produce from it a set of consistent parameters for one of these ''benchmark'' machines. Attention is directed to the choice of parameters for a collider in the 300 GeV energy range, operating at a gradient on the order of 200 MV/m, using X-band power sources to drive a conventional disk-loaded accelerating structure. These rf power sources, while not completely conventional represent a reasonable extrapolation from present technology. The choice of linac parameters is strongly coupled to various beam-beam effects which take place when the electron and positron bunches collide. We summarize these beam-beam effects, and then return to the rf design of a 650 GeV center-of-mass collider. 14 refs.

  12. Laser beam shaping for biomedical microscopy techniques

    NASA Astrophysics Data System (ADS)

    Laskin, Alexander; Kaiser, Peter; Laskin, Vadim; Ostrun, Aleksei

    2016-04-01

    Uniform illumination of a working field is very important in optical systems of confocal microscopy and various implementations of fluorescence microscopy like TIR, SSIM, STORM, PALM to enhance performance of these laser-based research techniques. Widely used TEM00 laser sources are characterized by essentially non-uniform Gaussian intensity profile which leads usually to non-uniform intensity distribution in a microscope working field or in a field of microlenses array of a confocal microscope optical system, this non-uniform illumination results in instability of measuring procedure and reducing precision of quantitative measurements. Therefore transformation of typical Gaussian distribution of a TEM00 laser to flat-top (top hat) profile is an actual technical task, it is solved by applying beam shaping optics. Due to high demands to optical image quality the mentioned techniques have specific requirements to a uniform laser beam: flatness of phase front and extended depth of field, - from this point of view the microscopy techniques are similar to holography and interferometry. There are different refractive and diffractive beam shaping approaches used in laser industrial and scientific applications, but only few of them are capable to fulfil the optimum conditions for beam quality required in discussed microscopy techniques. We suggest applying refractive field mapping beam shapers πShaper, which operational principle presumes almost lossless transformation of Gaussian to flat-top beam with flatness of output wavefront, conserving of beam consistency, providing collimated low divergent output beam, high transmittance, extended depth of field, negligible wave aberration, and achromatic design provides capability to work with several lasers with different wavelengths simultaneously. The main function of a beam shaper is transformation of laser intensity profile, further beam transformation to provide optimum for a particular technique spot size and shape has to

  13. LEDA BEAM DIAGNOSTICS INSTRUMENTATION: BEAM POSITION MONITORS

    SciTech Connect

    D. BARR; ET AL

    2000-05-01

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

  14. Neutral particle beam intensity controller

    DOEpatents

    Dagenhart, W.K.

    1984-05-29

    The neutral beam intensity controller is based on selected magnetic defocusing of the ion beam prior to neutralization. The defocused portion of the beam is dumped onto a beam dump disposed perpendicular to the beam axis. Selective defocusing is accomplished by means of a magnetic field generator disposed about the neutralizer so that the field is transverse to the beam axis. The magnetic field intensity is varied to provide the selected partial beam defocusing of the ions prior to neutralization. The desired focused neutral beam portion passes along the beam path through a defining aperture in the beam dump, thereby controlling the desired fraction of neutral particles transmitted to a utilization device without altering the kinetic energy level of the desired neutral particle fraction. By proper selection of the magnetic field intensity, virtually zero through 100% intensity control of the neutral beam is achieved.

  15. Tangent map analysis of the beam-beam interaction

    SciTech Connect

    Lee, S.Y.; Tepikian, S.

    1989-01-01

    We studied the tangent map of the beam-beam interaction and found no evidence of beam-beam instability for /epsilon/ = 0.04. Tracking study with tune modulation shows however large emittance growth due to the sum resonances. The emittance growth is due to the multiple crossing of the sum resonances. 12 refs., 7 figs.

  16. Beam-beam tuneshift during the TEVATRON squeeze

    SciTech Connect

    Mane, S.R.

    1988-11-01

    We calculate the beam-beam tuneshift during the squeeze of the beam in the Tevatron from injection to mini-beta. We find that for the beam emittances typically used, there is little variation of the tuneshift, in either plane, during the squeeze. 7 figs., 2 tabs.

  17. Learning structurally consistent undirected probabilistic graphical models.

    PubMed

    Roy, Sushmita; Lane, Terran; Werner-Washburne, Margaret

    2009-01-01

    In many real-world domains, undirected graphical models such as Markov random fields provide a more natural representation of the statistical dependency structure than directed graphical models. Unfortunately, structure learning of undirected graphs using likelihood-based scores remains difficult because of the intractability of computing the partition function. We describe a new Markov random field structure learning algorithm, motivated by canonical parameterization of Abbeel et al. We provide computational improvements on their parameterization by learning per-variable canonical factors, which makes our algorithm suitable for domains with hundreds of nodes. We compare our algorithm against several algorithms for learning undirected and directed models on simulated and real datasets from biology. Our algorithm frequently outperforms existing algorithms, producing higher-quality structures, suggesting that enforcing consistency during structure learning is beneficial for learning undirected graphs.

  18. Plasma Diffusion in Self-Consistent Fluctuations

    NASA Technical Reports Server (NTRS)

    Smets, R.; Belmont, G.; Aunai, N.

    2012-01-01

    The problem of particle diffusion in position space, as a consequence ofeleclromagnetic fluctuations is addressed. Numerical results obtained with a self-consistent hybrid code are presented, and a method to calculate diffusion coefficient in the direction perpendicular to the mean magnetic field is proposed. The diffusion is estimated for two different types of fluctuations. The first type (resuiting from an agyrotropic in itiai setting)is stationary, wide band white noise, and associated to Gaussian probability distribution function for the magnetic fluctuations. The second type (result ing from a Kelvin-Helmholtz instability) is non-stationary, with a power-law spectrum, and a non-Gaussian probabi lity distribution function. The results of the study allow revisiting the question of loading particles of solar wind origin in the Earth magnetosphere.

  19. Consistent thermostatistics forbids negative absolute temperatures

    NASA Astrophysics Data System (ADS)

    Dunkel, Jörn; Hilbert, Stefan

    2014-01-01

    Over the past 60 years, a considerable number of theories and experiments have claimed the existence of negative absolute temperature in spin systems and ultracold quantum gases. This has led to speculation that ultracold gases may be dark-energy analogues and also suggests the feasibility of heat engines with efficiencies larger than one. Here, we prove that all previous negative temperature claims and their implications are invalid as they arise from the use of an entropy definition that is inconsistent both mathematically and thermodynamically. We show that the underlying conceptual deficiencies can be overcome if one adopts a microcanonical entropy functional originally derived by Gibbs. The resulting thermodynamic framework is self-consistent and implies that absolute temperature remains positive even for systems with a bounded spectrum. In addition, we propose a minimal quantum thermometer that can be implemented with available experimental techniques.

  20. Trisomy 21 consistently activates the interferon response.

    PubMed

    Sullivan, Kelly D; Lewis, Hannah C; Hill, Amanda A; Pandey, Ahwan; Jackson, Leisa P; Cabral, Joseph M; Smith, Keith P; Liggett, L Alexander; Gomez, Eliana B; Galbraith, Matthew D; DeGregori, James; Espinosa, Joaquín M

    2016-07-29

    Although it is clear that trisomy 21 causes Down syndrome, the molecular events acting downstream of the trisomy remain ill defined. Using complementary genomics analyses, we identified the interferon pathway as the major signaling cascade consistently activated by trisomy 21 in human cells. Transcriptome analysis revealed that trisomy 21 activates the interferon transcriptional response in fibroblast and lymphoblastoid cell lines, as well as circulating monocytes and T cells. Trisomy 21 cells show increased induction of interferon-stimulated genes and decreased expression of ribosomal proteins and translation factors. An shRNA screen determined that the interferon-activated kinases JAK1 and TYK2 suppress proliferation of trisomy 21 fibroblasts, and this defect is rescued by pharmacological JAK inhibition. Therefore, we propose that interferon activation, likely via increased gene dosage of the four interferon receptors encoded on chromosome 21, contributes to many of the clinical impacts of trisomy 21, and that interferon antagonists could have therapeutic benefits.

  1. Reliability and Consistency of Surface Contamination Measurements

    SciTech Connect

    Rouppert, F.; Rivoallan, A.; Largeron, C.

    2002-02-26

    Surface contamination evaluation is a tough problem since it is difficult to isolate the radiations emitted by the surface, especially in a highly irradiating atmosphere. In that case the only possibility is to evaluate smearable (removeable) contamination since ex-situ countings are possible. Unfortunately, according to our experience at CEA, these values are not consistent and thus non relevant. In this study, we show, using in-situ Fourier Transform Infra Red spectrometry on contaminated metal samples, that fixed contamination seems to be chemisorbed and removeable contamination seems to be physisorbed. The distribution between fixed and removeable contamination appears to be variable. Chemical equilibria and reversible ion exchange mechanisms are involved and are closely linked to environmental conditions such as humidity and temperature. Measurements of smearable contamination only give an indication of the state of these equilibria between fixed and removeable contamination at the time and in the environmental conditions the measurements were made.

  2. Consistent evolution in a pedestrian flow

    NASA Astrophysics Data System (ADS)

    Guan, Junbiao; Wang, Kaihua

    2016-03-01

    In this paper, pedestrian evacuation considering different human behaviors is studied by using a cellular automaton (CA) model combined with the snowdrift game theory. The evacuees are divided into two types, i.e. cooperators and defectors, and two different human behaviors, herding behavior and independent behavior, are investigated. It is found from a large amount of numerical simulations that the ratios of the corresponding evacuee clusters are evolved to consistent states despite 11 typically different initial conditions, which may largely owe to self-organization effect. Moreover, an appropriate proportion of initial defectors who are of herding behavior, coupled with an appropriate proportion of initial defectors who are of rationally independent thinking, are two necessary factors for short evacuation time.

  3. Scattering of a Tightly Focused Beam by an Optically Trapped Particle

    NASA Technical Reports Server (NTRS)

    Lock, James A.; Wrbanek, Susan Y.; Weiland, Kenneth E.

    2006-01-01

    Near-forward scattering of an optically trapped 5 m radius polystyrene latex sphere by the trapping beam was examined both theoretically and experimentally. Since the trapping beam is tightly focused, the beam fields superpose and interfere with the scattered fields in the forward hemisphere. The observed light intensity consists of a series of concentric bright and dark fringes centered about the forward scattering direction. Both the number of fringes and their contrast depend on the position of the trapping beam focal waist with respect to the sphere. The fringes are caused by diffraction due to the truncation of the tail of the trapping beam as the beam is transmitted through the sphere.

  4. Beam-foil spectroscopy

    SciTech Connect

    Berry, H.G.; Hass, M.

    1982-01-01

    A brief survey of some applications of beam-foil spectroscopy is presented. Among the topics covered are lifetime and magnetic moment measurements, nuclear alignment, and polarized light production. (AIP)

  5. Bunched beam stochastic cooling

    SciTech Connect

    Wei, Jie.

    1992-01-01

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

  6. Bunched beam stochastic cooling

    SciTech Connect

    Wei, Jie

    1992-09-01

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

  7. Ion beam texturing

    NASA Technical Reports Server (NTRS)

    Hudson, W. R.

    1976-01-01

    A microscopic surface texture is created by sputter etching a surface while simultaneously sputter depositing a lower sputter yield material onto the surface. A xenon ion beam source has been used to perform this texturing process on samples as large as three centimeters in diameter. Ion beam textured surface structures have been characterized with SEM photomicrographs for a large number of materials including Cu, Al, Si, Ti, Ni, Fe, Stainless steel, Au, and Ag. Surfaces have been textured using a variety of low sputter yield materials - Ta, Mo, Nb, and Ti. The initial stages of the texture creation have been documented, and the technique of ion beam sputter removal of any remaining deposited material has been studied. A number of other texturing parameters have been studied such as the variation of the texture with ion beam power, surface temperature, and the rate of texture growth with sputter etching time.

  8. Pulsed ion beam source

    DOEpatents

    Greenly, John B.

    1997-01-01

    An improved pulsed ion beam source having a new biasing circuit for the fast magnetic field. This circuit provides for an initial negative bias for the field created by the fast coils in the ion beam source which pre-ionize the gas in the source, ionize the gas and deliver the gas to the proper position in the accelerating gap between the anode and cathode assemblies in the ion beam source. The initial negative bias improves the interaction between the location of the nulls in the composite magnetic field in the ion beam source and the position of the gas for pre-ionization and ionization into the plasma as well as final positioning of the plasma in the accelerating gap. Improvements to the construction of the flux excluders in the anode assembly are also accomplished by fabricating them as layered structures with a high melting point, low conductivity material on the outsides with a high conductivity material in the center.

  9. Focused ion beam system

    SciTech Connect

    Leung, K.; Gough, R.A.; Ji, Q.; Lee, Y.Y.

    1999-08-31

    A focused ion beam (FIB) system produces a final beam spot size down to 0.1 {mu}m or less and an ion beam output current on the order of microamps. The FIB system increases ion source brightness by properly configuring the first (plasma) and second (extraction) electrodes. The first electrode is configured to have a high aperture diameter to electrode thickness aspect ratio. Additional accelerator and focusing electrodes are used to produce the final beam. As few as five electrodes can be used, providing a very compact FIB system with a length down to only 20 mm. Multibeamlet arrangements with a single ion source can be produced to increase throughput. The FIB system can be used for nanolithography and doping applications for fabrication of semiconductor devices with minimum feature sizes of 0.1 m or less. 13 figs.

  10. Final focus test beam

    SciTech Connect

    Not Available

    1991-03-01

    This report discusses the following: the Final Focus Test Beam Project; optical design; magnets; instrumentation; magnetic measurement and BPM calibration; mechanical alignment and stabilization; vacuum system; power supplies; control system; radiation shielding and personnel protection; infrastructure; and administration.

  11. Focused ion beam system

    DOEpatents

    Leung, Ka-Ngo; Gough, Richard A.; Ji, Qing; Lee, Yung-Hee Yvette

    1999-01-01

    A focused ion beam (FIB) system produces a final beam spot size down to 0.1 .mu.m or less and an ion beam output current on the order of microamps. The FIB system increases ion source brightness by properly configuring the first (plasma) and second (extraction) electrodes. The first electrode is configured to have a high aperture diameter to electrode thickness aspect ratio. Additional accelerator and focusing electrodes are used to produce the final beam. As few as five electrodes can be used, providing a very compact FIB system with a length down to only 20 mm. Multibeamlet arrangements with a single ion source can be produced to increase throughput. The FIB system can be used for nanolithography and doping applications for fabrication of semiconductor devices with minimum feature sizes of 0.1 .mu.m or less.

  12. Quantifying consistent individual differences in habitat selection.

    PubMed

    Leclerc, Martin; Vander Wal, Eric; Zedrosser, Andreas; Swenson, Jon E; Kindberg, Jonas; Pelletier, Fanie

    2016-03-01

    Habitat selection is a fundamental behaviour that links individuals to the resources required for survival and reproduction. Although natural selection acts on an individual's phenotype, research on habitat selection often pools inter-individual patterns to provide inferences on the population scale. Here, we expanded a traditional approach of quantifying habitat selection at the individual level to explore the potential for consistent individual differences of habitat selection. We used random coefficients in resource selection functions (RSFs) and repeatability estimates to test for variability in habitat selection. We applied our method to a detailed dataset of GPS relocations of brown bears (Ursus arctos) taken over a period of 6 years, and assessed whether they displayed repeatable individual differences in habitat selection toward two habitat types: bogs and recent timber-harvest cut blocks. In our analyses, we controlled for the availability of habitat, i.e. the functional response in habitat selection. Repeatability estimates of habitat selection toward bogs and cut blocks were 0.304 and 0.420, respectively. Therefore, 30.4 and 42.0 % of the population-scale habitat selection variability for bogs and cut blocks, respectively, was due to differences among individuals, suggesting that consistent individual variation in habitat selection exists in brown bears. Using simulations, we posit that repeatability values of habitat selection are not related to the value and significance of β estimates in RSFs. Although individual differences in habitat selection could be the results of non-exclusive factors, our results illustrate the evolutionary potential of habitat selection.

  13. Radiometric consistency assessment of hyperspectral infrared sounders

    NASA Astrophysics Data System (ADS)

    Wang, L.; Han, Y.; Jin, X.; Chen, Y.; Tremblay, D. A.

    2015-07-01

    The radiometric and spectral consistency among the Atmospheric Infrared Sounder (AIRS), the Infrared Atmospheric Sounding Interferometer (IASI), and the Cross-track Infrared Sounder (CrIS) is fundamental for the creation of long-term infrared (IR) hyperspectral radiance benchmark datasets for both inter-calibration and climate-related studies. In this study, the CrIS radiance measurements on Suomi National Polar-orbiting Partnership (SNPP) satellite are directly compared with IASI on MetOp-A and -B at the finest spectral scale and with AIRS on Aqua in 25 selected spectral regions through one year of simultaneous nadir overpass (SNO) observations to evaluate radiometric consistency of these four hyperspectral IR sounders. The spectra from different sounders are paired together through strict spatial and temporal collocation. The uniform scenes are selected by examining the collocated Visible Infrared Imaging Radiometer Suite (VIIRS) pixels. Their brightness temperature (BT) differences are then calculated by converting the spectra onto common spectral grids. The results indicate that CrIS agrees well with IASI on MetOp-A and IASI on MetOp-B at the longwave IR (LWIR) and middle-wave IR (MWIR) bands with 0.1-0.2 K differences. There are no apparent scene-dependent patterns for BT differences between CrIS and IASI for individual spectral channels. CrIS and AIRS are compared at the 25 spectral regions for both Polar and Tropical SNOs. The combined global SNO datasets indicate that, the CrIS-AIRS BT differences are less than or around 0.1 K among 21 of 25 comparison spectral regions and they range from 0.15 to 0.21 K in the remaining 4 spectral regions. CrIS-AIRS BT differences in some comparison spectral regions show weak scene-dependent features.

  14. Radiometric consistency assessment of hyperspectral infrared sounders

    NASA Astrophysics Data System (ADS)

    Wang, L.; Han, Y.; Jin, X.; Chen, Y.; Tremblay, D. A.

    2015-11-01

    The radiometric and spectral consistency among the Atmospheric Infrared Sounder (AIRS), the Infrared Atmospheric Sounding Interferometer (IASI), and the Cross-track Infrared Sounder (CrIS) is fundamental for the creation of long-term infrared (IR) hyperspectral radiance benchmark data sets for both intercalibration and climate-related studies. In this study, the CrIS radiance measurements on Suomi National Polar-orbiting Partnership (SNPP) satellite are directly compared with IASI on MetOp-A and MetOp-B at the finest spectral scale and with AIRS on Aqua in 25 selected spectral regions through simultaneous nadir overpass (SNO) observations in 2013, to evaluate radiometric consistency of these four hyperspectral IR sounders. The spectra from different sounders are paired together through strict spatial and temporal collocation. The uniform scenes are selected by examining the collocated Visible Infrared Imaging Radiometer Suite (VIIRS) pixels. Their brightness temperature (BT) differences are then calculated by converting the spectra onto common spectral grids. The results indicate that CrIS agrees well with IASI on MetOp-A and IASI on MetOp-B at the long-wave IR (LWIR) and middle-wave IR (MWIR) bands with 0.1-0.2 K differences. There are no apparent scene-dependent patterns for BT differences between CrIS and IASI for individual spectral channels. CrIS and AIRS are compared at the 25 spectral regions for both polar and tropical SNOs. The combined global SNO data sets indicate that the CrIS-AIRS BT differences are less than or around 0.1 K among 21 of 25 spectral regions and they range from 0.15 to 0.21 K in the remaining four spectral regions. CrIS-AIRS BT differences in some comparison spectral regions show weak scene-dependent features.

  15. Test beams and polarized fixed target beams at the NLC

    NASA Astrophysics Data System (ADS)

    Keller, Lewis; Pitthan, Rainer; Rokni, Sayed; Thompson, Kathleen; Kolomensky, Yury

    2001-07-01

    A conceptual program to use NLC beams for test beams and fixed target physics is described. Primary undisrupted polarized beams would be the most simple to use, but for NLC, the disrupted beams are of good enough quality that they could also be used, after collimation of the low energy tails, for test beams and fixed target physics. Pertinent issues are: what is the compelling physics, what are the requirements on beams and running time, and what is the impact on colliding beam physics running. A list of physics topics is given; one topic (Mo/ller Scattering) is treated in more depth.

  16. SPIDER beam dump as diagnostic of the particle beam

    NASA Astrophysics Data System (ADS)

    Zaupa, M.; Dalla Palma, M.; Sartori, E.; Brombin, M.; Pasqualotto, R.

    2016-11-01

    The beam power produced by the negative ion source for the production of ion of deuterium extracted from RF plasma is mainly absorbed by the beam dump component which has been designed also for measuring the temperatures on the dumping panels for beam diagnostics. A finite element code has been developed to characterize, by thermo-hydraulic analysis, the sensitivity of the beam dump to the different beam parameters. The results prove the capability of diagnosing the beam divergence and the horizontal misalignment, while the entity of the halo fraction appears hardly detectable without considering the other foreseen diagnostics like tomography and beam emission spectroscopy.

  17. Beam/seam alignment control for electron beam welding

    DOEpatents

    Burkhardt, Jr., James H.; Henry, J. James; Davenport, Clyde M.

    1980-01-01

    This invention relates to a dynamic beam/seam alignment control system for electron beam welds utilizing video apparatus. The system includes automatic control of workpiece illumination, near infrared illumination of the workpiece to limit the range of illumination and camera sensitivity adjustment, curve fitting of seam position data to obtain an accurate measure of beam/seam alignment, and automatic beam detection and calculation of the threshold beam level from the peak beam level of the preceding video line to locate the beam or seam edges.

  18. Test Beams and Polarized Fixed Target Beams at the NLC

    SciTech Connect

    Pitthan, Rainer

    2001-01-17

    A conceptual program to use NLC beams for test beams and fixed target physics is described. Primary undisrupted polarized beams would be the most simple to use, but for NLC, the disrupted beams are of good enough quality that they could also be used, after collimation of the low energy tails, for test beams and fixed target physics. Pertinent issues are: what is the compelling physics, what are the requirements on beams and running time, and what is the impact on colliding beam physics running. A list of physics topics is given; one topic (Moeller Scattering) is treated in more depth.

  19. Batten augmented triangular beam

    NASA Technical Reports Server (NTRS)

    Adams, Louis R.; Hedgepeth, John M.

    1986-01-01

    The BAT (Batten-Augmented Triangular) BEAM is characterized by battens which are buckled in the deployed state, thus preloading the truss. The preload distribution is determined, and the effects of various external loading conditions are investigated. The conceptual design of a deployer is described and loads are predicted. The influence of joint imperfections on effective member stiffness is investigated. The beam is assessed structurally.

  20. Intense ion beam generator

    DOEpatents

    Humphries, Jr., Stanley; Sudan, Ravindra N.

    1977-08-30

    Methods and apparatus for producing intense megavolt ion beams are disclosed. In one embodiment, a reflex triode-type pulsed ion accelerator is described which produces ion pulses of more than 5 kiloamperes current with a peak energy of 3 MeV. In other embodiments, the device is constructed so as to focus the beam of ions for high concentration and ease of extraction, and magnetic insulation is provided to increase the efficiency of operation.

  1. High intensity neutrino beams

    SciTech Connect

    Ichikawa, A. K.

    2015-07-15

    High-intensity proton accelerator complex enabled long baseline neutrino oscillation experiments with a precisely controlled neutrino beam. The beam power so far achieved is a few hundred kW with enourmorous efforts of accelerator physicists and engineers. However, to fully understand the lepton mixing structure, MW-class accelerators are desired. We describe the current intensity-frontier high-energy proton accelerators, their plans to go beyond and technical challenges in the neutrino beamline facilities.

  2. Betatrons with kiloampere beams

    SciTech Connect

    Peterson, J.M.

    1982-11-01

    Although the magnetic-induction method of acceleration used in the betatron is inherently capable of accelerating intense particle beams to high energy, many beam-instability questions arise when beams in the kilo-ampere range are considered. The intense electromagnetic fields produced by the beam, and by the image currents and charges induced in the surrounding walls, can produce very disruptive effects. Several unstable modes of collective oscillation are possible; the suppression of any one of them usually involves energy spread for Landau damping and careful design of the electrical character of the vacuum chamber. The various design criteria are often mutually incompatible. Space-charge detuning can be severe unless large beam apertures and high-energy injection are used. In order to have an acceptably low degree of space-charge detuning in the acceleration of a 10-kilo-ampere electron beam, for example, an injection energy on the order of 50 MeV seems necessary, in which case the forces due to nearby wall images can have a larger effect than the internal forces of the beam. A method of image compensation was invented for reducing the net image forces; it serves also to decrease the longitudinal beam impedance and thus helps alleviate the longitudinal instability as well. In order to avoid the ion-electron collective instability a vacuum in the range of 10/sup -8/ torr is required for an acceleration time of 1 millisecond. A multi-ring betatron system using the 50-MeV Advanced Test Accelerator at LLNL as an injector was conceptually designed.

  3. Wire Scanner Beam Profile Measurements: LANSCE Facility Beam Development

    SciTech Connect

    Gilpatrick, John D.; Batygin, Yuri K.; Gonzales, Fermin; Gruchalla, Michael E.; Kutac, Vincent G.; Martinez, Derwin; Sedillo, James Daniel; Pillai, Chandra; Rodriguez Esparza, Sergio; Smith, Brian G.

    2012-05-15

    The Los Alamos Neutron Science Center (LANSCE) is replacing Wire Scanner (WS) beam profile measurement systems. Three beam development tests have taken place to test the new wire scanners under beam conditions. These beam development tests have integrated the WS actuator, cable plant, electronics processors and associated software and have used H{sup -} beams of different beam energy and current conditions. In addition, the WS measurement-system beam tests verified actuator control systems for minimum profile bin repeatability and speed, checked for actuator backlash and positional stability, tested the replacement of simple broadband potentiometers with narrow band resolvers, and tested resolver use with National Instruments Compact Reconfigurable Input and Output (cRIO) Virtual Instrumentation. These beam tests also have verified how trans-impedance amplifiers react with various types of beam line background noise and how noise currents were not generated. This paper will describe these beam development tests and show some resulting data.

  4. High power beam analysis

    NASA Astrophysics Data System (ADS)

    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.

  5. Obtaining an equivalent beam

    NASA Technical Reports Server (NTRS)

    Butler, Thomas G.

    1990-01-01

    In modeling a complex structure the researcher was faced with a component that would have logical appeal if it were modeled as a beam. The structure was a mast of a robot controlled gantry crane. The structure up to this point already had a large number of degrees of freedom, so the idea of conserving grid points by modeling the mast as a beam was attractive. The researcher decided to make a separate problem of of the mast and model it in three dimensions with plates, then extract the equivalent beam properties by setting up the loading to simulate beam-like deformation and constraints. The results could then be used to represent the mast as a beam in the full model. A comparison was made of properties derived from models of different constraints versus manual calculations. The researcher shows that the three-dimensional model is ineffective in trying to conform to the requirements of an equivalent beam representation. If a full 3-D plate model were used in the complete representation of the crane structure, good results would be obtained. Since the attempt is to economize on the size of the model, a better way to achieve the same results is to use substructuring and condense the mast to equivalent end boundary and intermediate mass points.

  6. Electron beam dose calculations.

    PubMed

    Hogstrom, K R; Mills, M D; Almond, P R

    1981-05-01

    Electron beam dose distributions in the presence of inhomogeneous tissue are calculated by an algorithm that sums the dose distribution of individual pencil beams. The off-axis dependence of the pencil beam dose distribution is described by the Fermi-Eyges theory of thick-target multiple Coulomb scattering. Measured square-field depth-dose data serve as input for the calculations. Air gap corrections are incorporated and use data from'in-air' measurements in the penumbra of the beam. The effective depth, used to evaluate depth-dose, and the sigma of the off-axis Gaussian spread against depth are calculated by recursion relations from a CT data matrix for the material underlying individual pencil beams. The correlation of CT number with relative linear stopping power and relative linear scattering power for various tissues is shown. The results of calculations are verified by comparison with measurements in a 17 MeV electron beam from the Therac 20 linear accelerator. Calculated isodose lines agree nominally to within 2 mm of measurements in a water phantom. Similar agreement is observed in cork slabs simulating lung. Calculations beneath a bone substitute illustrate a weakness in the calculation. Finally a case of carcinoma in the maxillary antrum is studied. The theory suggests an alternative method for the calculation of depth-dose of rectangular fields.

  7. Photon beam position monitor

    DOEpatents

    Kuzay, T.M.; Shu, D.

    1995-02-07

    A photon beam position monitor is disclosed for use in the front end of a beamline of a high heat flux and high energy photon source such as a synchrotron radiation storage ring detects and measures the position and, when a pair of such monitors are used in tandem, the slope of a photon beam emanating from an insertion device such as a wiggler or an undulator inserted in the straight sections of the ring. The photon beam position monitor includes a plurality of spaced blades for precisely locating the photon beam, with each blade comprised of chemical vapor deposition (CVD) diamond with an outer metal coating of a photon sensitive metal such as tungsten, molybdenum, etc., which combination emits electrons when a high energy photon beam is incident upon the blade. Two such monitors are contemplated for use in the front end of the beamline, with the two monitors having vertically and horizontally offset detector blades to avoid blade ''shadowing''. Provision is made for aligning the detector blades with the photon beam and limiting detector blade temperature during operation. 18 figs.

  8. Photon beam position monitor

    DOEpatents

    Kuzay, Tuncer M.; Shu, Deming

    1995-01-01

    A photon beam position monitor for use in the front end of a beamline of a high heat flux and high energy photon source such as a synchrotron radiation storage ring detects and measures the position and, when a pair of such monitors are used in tandem, the slope of a photon beam emanating from an insertion device such as a wiggler or an undulator inserted in the straight sections of the ring. The photon beam position monitor includes a plurality of spaced blades for precisely locating the photon beam, with each blade comprised of chemical vapor deposition (CVD) diamond with an outer metal coating of a photon sensitive metal such as tungsten, molybdenum, etc., which combination emits electrons when a high energy photon beam is incident upon the blade. Two such monitors are contemplated for use in the front end of the beamline, with the two monitors having vertically and horizontally offset detector blades to avoid blade "shadowing". Provision is made for aligning the detector blades with the photon beam and limiting detector blade temperature during operation.

  9. Improved Morphable Beam Device for Equipping Camera at Beam End

    NASA Astrophysics Data System (ADS)

    Mizunuma, Shintaro; Matunaga, Saburo; Kisa, Nobuhiro

    To conduct remote inspection missions, the authors has proposed Morphable Beam Device (MBD) and developed an experimental device using a bendable beam without any articulated joints. In the device, a beam is deployed, enabling a wide range of shapes and lengths. In this paper, a prototype of an MBD is introduced and a beam shaping theory for two beam shaping mechanisms of slide and rotation types is discussed and verified with experiments.

  10. Generating polarization vortices by using helical beams and a Twyman Green interferometer.

    PubMed

    Fu, Shiyao; Gao, Chunqing; Shi, Yang; Dai, Kunjian; Zhong, Lei; Zhang, Shikun

    2015-04-15

    A stable interferometric arrangement consisting of a polarizing beam splitter, a reflector, and a right-angle prism is designed to transform helical beams into polarization vortices. The computer-generated holograms are loaded on the liquid crystal spatial light modulator (LC-SLM) in order to generate different helical beams. Then the helical beams are transformed into polarization vortices with different kinds of intensity distribution successfully.

  11. Holographic memory using beam steering

    NASA Technical Reports Server (NTRS)

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

    2007-01-01

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

  12. Photodetachment process for beam neutralization

    DOEpatents

    Fink, Joel H. [Livermore, CA; Frank, Alan M. [Livermore, CA

    1979-02-20

    A process for neutralization of accelerated ions employing photo-induced charge detachment. The process involves directing a laser beam across the path of a negative ion beam such as to effect photodetachment of electrons from the beam ions. The frequency of the laser beam employed is selected to provide the maximum cross-section for the photodetachment process.

  13. Photodetachment process for beam neutralization

    DOEpatents

    Fink, J.H.; Frank, A.M.

    1979-02-20

    A process for neutralization of accelerated ions employing photo-induced charge detachment is disclosed. The process involves directing a laser beam across the path of a negative ion beam such as to effect photodetachment of electrons from the beam ions. The frequency of the laser beam employed is selected to provide the maximum cross-section for the photodetachment process. 2 figs.

  14. Polynomial Beam Element Analysis Module

    SciTech Connect

    Ning, S. Andrew

    2013-05-01

    pBEAM (Polynomial Beam Element Analysis Module) is a finite element code for beam-like structures. The methodology uses Euler? Bernoulli beam elements with 12 degrees of freedom (3 translation and 3 rotational at each end of the element).

  15. Single element laser beam shaper

    DOEpatents

    Zhang, Shukui; Michelle D. Shinn

    2005-09-13

    A single lens laser beam shaper for converting laser beams from any spatial profile to a flat-top or uniform spatial profile. The laser beam shaper includes a lens having two aspheric surfaces. The beam shaper significantly simplifies the overall structure in comparison with conventional 2-element systems and therefore provides great ease in alignment and reduction of cost.

  16. Experimental demonstration of a Laguerre-Gaussian correlated Schell-model vortex beam.

    PubMed

    Chen, Yahong; Wang, Fei; Zhao, Chengliang; Cai, Yangjian

    2014-03-10

    Laguerre-Gaussian correlated Schell-model (LGCSM) vortex beam is introduced as an extension of LGCSM beam which was proposed [Opt. Lett.38, 91 (2013)Opt. Lett.38, 1814 (2013)] just recently. Explicit formula for a LGCSM vortex beam propagating through a stigmatic ABCD optical system is derived, and the propagation properties of such beam in free space and the focusing properties of such beam are studied numerically. Furthermore, we carry out experimental generation of a LGCSM vortex beam, and studied its focusing properties. It is found that the propagation and focusing properties of a LGCSM vortex beam are different from that of a LGCSM beam, and we can shape the beam profile of a LGCSM vortex at the focal plane (or in the far field) by varying its initial spatial coherence. Our experimental results are consistent with the theoretical predictions, and our results will be useful for particle trapping.

  17. Generation and propagation of a vector cosine-Gaussian correlated beam with radial polarization.

    PubMed

    Zhu, Shijun; Chen, Yahong; Wang, Jing; Wang, Haiyan; Li, Zhenhua; Cai, Yangjian

    2015-12-28

    Scalar cosine-Gaussian-correlated Schell-model (CGCSM) beams of circular or rectangular symmetry were introduced just recently. In this paper, a new kind of partially coherent vector beam named vector CGCSM beam with radial polarization (i.e., radially polarized CGCSM beam) is introduced. The realizability conditions for a radially polarized CGCSM source and the beam condition for radiation generated by such source are derived. The statistical properties, such as the average intensity, the degree of coherence, the degree of polarization and the state of polarization, of a radially polarized CGCSM beam focused by a thin lens are analyzed in detail. It is found that the statistical properties of a radially polarized CGCSM beam are quite different from those of a conventional radial polarized partially coherent beam with Gaussian correlated Schell-model function. Furthermore, we first report experimental generation of a radially polarized CGCSM beam and measure its focusing properties. Our experimental results are consistent with the theoretical predictions.

  18. Suppression of Space Charge Induced Beam Halo in Nonlinear Focusing Channel

    SciTech Connect

    Batygin, Yuri Konstantinovich; Scheinker, Alexander; Kurennoy, Sergey; Li, Chao

    2016-01-29

    An intense non-uniform particle beam exhibits strong emittance growth and halo formation in focusing channels due to nonlinear space charge forces of the beam. This phenomenon limits beam brightness and results in particle losses. The problem is connected with irreversible distortion of phase space volume of the beam in conventional focusing structures due to filamentation in phase space. Emittance growth is accompanied by halo formation in real space, which results in inevitable particle losses. We discuss a new approach for solving a self-consistent problem for a matched non-uniform beam in two-dimensional geometry. The resulting solution is applied to the problem of beam transport, while avoiding emittance growth and halo formation by the use of nonlinear focusing field. Conservation of a beam distribution function is demonstrated analytically and by particle-in-cell simulation for a beam with a realistic beam distribution.

  19. Suppression of Space Charge Induced Beam Halo in Nonlinear Focusing Channel

    DOE PAGES

    Batygin, Yuri Konstantinovich; Scheinker, Alexander; Kurennoy, Sergey; ...

    2016-01-29

    An intense non-uniform particle beam exhibits strong emittance growth and halo formation in focusing channels due to nonlinear space charge forces of the beam. This phenomenon limits beam brightness and results in particle losses. The problem is connected with irreversible distortion of phase space volume of the beam in conventional focusing structures due to filamentation in phase space. Emittance growth is accompanied by halo formation in real space, which results in inevitable particle losses. We discuss a new approach for solving a self-consistent problem for a matched non-uniform beam in two-dimensional geometry. The resulting solution is applied to the problemmore » of beam transport, while avoiding emittance growth and halo formation by the use of nonlinear focusing field. Conservation of a beam distribution function is demonstrated analytically and by particle-in-cell simulation for a beam with a realistic beam distribution.« less

  20. Measurement of ultra-low ion energy of decelerated ion beam using a deflecting electric field

    NASA Astrophysics Data System (ADS)

    Thopan, P.; Suwannakachorn, D.; Tippawan, U.; Yu, L. D.

    2015-12-01

    In investigation on ultra-low-energy ion bombardment effect on DNA, an ion beam deceleration lens was developed for high-quality ultra-low-energy ion beam. Measurement of the ion energy after deceleration was necessary to confirm the ion beam really decelerated as theoretically predicted. In contrast to conventional methods, this work used a simple deflecting electrostatic field after the deceleration lens to bend the ion beam. The beam bending distance depended on the ion energy and was described and simulated. A system for the measurement of the ion beam energy was constructed. It consisted of a pair of parallel electrode plates to generate the deflecting electrical field, a copper rod measurement piece to detect ion beam current, a vernier caliper to mark the beam position, a stepping motor to translate the measurement rod, and a webcam-camera to read the beam bending distance. The entire system was installed after the ion-beam deceleration lens inside the large chamber of the bioengineering vertical ion beam line. Moving the measurement rod across the decelerated ion beam enabled to obtain beam profiles, from which the beam bending distance could be known and the ion beam energy could be calculated. The measurement results were in good agreement with theoretical and simulated results.

  1. Retrocausation, Consistency, and the Bilking Paradox

    NASA Astrophysics Data System (ADS)

    Dobyns, York H.

    2011-11-01

    Retrocausation seems to admit of time paradoxes in which events prevent themselves from occurring and thereby create a physical instance of the liar's paradox, an event which occurs iff it does not occur. The specific version in which a retrocausal event is used to trigger an intervention which prevents its own future cause is called the bilking paradox (the event is bilked of its cause). The analysis of Echeverria, Klinkhammer, and Thorne (EKT) suggests time paradoxes cannot arise even in the presence of retrocausation. Any self-contradictory event sequence will be replaced in reality by a closely related but noncontradictory sequence. The EKT analysis implies that attempts to create bilking must instead produce logically consistent sequences wherein the bilked event arises from alternative causes. Bilking a retrocausal information channel of limited reliability usually results only in failures of signaling. An exception applies when the bilking is conducted in response only to some of the signal values that can be carried on the channel. Theoretical analysis based on EKT predicts that, since some of the channel outcomes are not bilked, the channel is capable of transmitting data with its normal reliability, and the paradox-avoidance effects will instead suppress the outcomes that would lead to forbidden (bilked) transmissions. A recent parapsychological experiment by Bem displays a retrocausal information channel of sufficient reliability to test this theoretical model of physical reality's response to retrocausal effects. A modified version with partial bilking would provide a direct test of the generality of the EKT mechanism.

  2. Ciliate communities consistently associated with coral diseases

    NASA Astrophysics Data System (ADS)

    Sweet, M. J.; Séré, M. G.

    2016-07-01

    Incidences of coral disease are increasing. Most studies which focus on diseases in these organisms routinely assess variations in bacterial associates. However, other microorganism groups such as viruses, fungi and protozoa are only recently starting to receive attention. This study aimed at assessing the diversity of ciliates associated with coral diseases over a wide geographical range. Here we show that a wide variety of ciliates are associated with all nine coral diseases assessed. Many of these ciliates such as Trochilia petrani and Glauconema trihymene feed on the bacteria which are likely colonizing the bare skeleton exposed by the advancing disease lesion or the necrotic tissue itself. Others such as Pseudokeronopsis and Licnophora macfarlandi are common predators of other protozoans and will be attracted by the increase in other ciliate species to the lesion interface. However, a few ciliate species (namely Varistrombidium kielum, Philaster lucinda, Philaster guamense, a Euplotes sp., a Trachelotractus sp. and a Condylostoma sp.) appear to harbor symbiotic algae, potentially from the coral themselves, a result which may indicate that they play some role in the disease pathology at the very least. Although, from this study alone we are not able to discern what roles any of these ciliates play in disease causation, the consistent presence of such communities with disease lesion interfaces warrants further investigation.

  3. Trisomy 21 consistently activates the interferon response

    PubMed Central

    Sullivan, Kelly D; Lewis, Hannah C; Hill, Amanda A; Pandey, Ahwan; Jackson, Leisa P; Cabral, Joseph M; Smith, Keith P; Liggett, L Alexander; Gomez, Eliana B; Galbraith, Matthew D; DeGregori, James; Espinosa, Joaquín M

    2016-01-01

    Although it is clear that trisomy 21 causes Down syndrome, the molecular events acting downstream of the trisomy remain ill defined. Using complementary genomics analyses, we identified the interferon pathway as the major signaling cascade consistently activated by trisomy 21 in human cells. Transcriptome analysis revealed that trisomy 21 activates the interferon transcriptional response in fibroblast and lymphoblastoid cell lines, as well as circulating monocytes and T cells. Trisomy 21 cells show increased induction of interferon-stimulated genes and decreased expression of ribosomal proteins and translation factors. An shRNA screen determined that the interferon-activated kinases JAK1 and TYK2 suppress proliferation of trisomy 21 fibroblasts, and this defect is rescued by pharmacological JAK inhibition. Therefore, we propose that interferon activation, likely via increased gene dosage of the four interferon receptors encoded on chromosome 21, contributes to many of the clinical impacts of trisomy 21, and that interferon antagonists could have therapeutic benefits. DOI: http://dx.doi.org/10.7554/eLife.16220.001 PMID:27472900

  4. Consistent lattice Boltzmann equations for phase transitions

    NASA Astrophysics Data System (ADS)

    Siebert, D. N.; Philippi, P. C.; Mattila, K. K.

    2014-11-01

    Unlike conventional computational fluid dynamics methods, the lattice Boltzmann method (LBM) describes the dynamic behavior of fluids in a mesoscopic scale based on discrete forms of kinetic equations. In this scale, complex macroscopic phenomena like the formation and collapse of interfaces can be naturally described as related to source terms incorporated into the kinetic equations. In this context, a novel athermal lattice Boltzmann scheme for the simulation of phase transition is proposed. The continuous kinetic model obtained from the Liouville equation using the mean-field interaction force approach is shown to be consistent with diffuse interface model using the Helmholtz free energy. Density profiles, interface thickness, and surface tension are analytically derived for a plane liquid-vapor interface. A discrete form of the kinetic equation is then obtained by applying the quadrature method based on prescribed abscissas together with a third-order scheme for the discretization of the streaming or advection term in the Boltzmann equation. Spatial derivatives in the source terms are approximated with high-order schemes. The numerical validation of the method is performed by measuring the speed of sound as well as by retrieving the coexistence curve and the interface density profiles. The appearance of spurious currents near the interface is investigated. The simulations are performed with the equations of state of Van der Waals, Redlich-Kwong, Redlich-Kwong-Soave, Peng-Robinson, and Carnahan-Starling.

  5. Consistent perturbations in an imperfect fluid

    SciTech Connect

    Sawicki, Ignacy; Amendola, Luca; Saltas, Ippocratis D.; Kunz, Martin E-mail: i.saltas@sussex.ac.uk E-mail: martin.kunz@unige.ch

    2013-01-01

    We present a new prescription for analysing cosmological perturbations in a more-general class of scalar-field dark-energy models where the energy-momentum tensor has an imperfect-fluid form. This class includes Brans-Dicke models, f(R) gravity, theories with kinetic gravity braiding and generalised galileons. We employ the intuitive language of fluids, allowing us to explicitly maintain a dependence on physical and potentially measurable properties. We demonstrate that hydrodynamics is not always a valid description for describing cosmological perturbations in general scalar-field theories and present a consistent alternative that nonetheless utilises the fluid language. We apply this approach explicitly to a worked example: k-essence non-minimally coupled to gravity. This is the simplest case which captures the essential new features of these imperfect-fluid models. We demonstrate the generic existence of a new scale separating regimes where the fluid is perfect and imperfect. We obtain the equations for the evolution of dark-energy density perturbations in both these regimes. The model also features two other known scales: the Compton scale related to the breaking of shift symmetry and the Jeans scale which we show is determined by the speed of propagation of small scalar-field perturbations, i.e. causality, as opposed to the frequently used definition of the ratio of the pressure and energy-density perturbations.

  6. Volume Haptics with Topology-Consistent Isosurfaces.

    PubMed

    Corenthy, Loc; Otaduy, Miguel A; Pastor, Luis; Garcia, Marcos

    2015-01-01

    Haptic interfaces offer an intuitive way to interact with and manipulate 3D datasets, and may simplify the interpretation of visual information. This work proposes an algorithm to provide haptic feedback directly from volumetric datasets, as an aid to regular visualization. The haptic rendering algorithm lets users perceive isosurfaces in volumetric datasets, and it relies on several design features that ensure a robust and efficient rendering. A marching tetrahedra approach enables the dynamic extraction of a piecewise linear continuous isosurface. Robustness is achieved using a continuous collision detection step coupled with state-of-the-art proxy-based rendering methods over the extracted isosurface. The introduced marching tetrahedra approach guarantees that the extracted isosurface will match the topology of an equivalent isosurface computed using trilinear interpolation. The proposed haptic rendering algorithm improves the consistency between haptic and visual cues computing a second proxy on the isosurface displayed on screen. Our experiments demonstrate the improvements on the isosurface extraction stage as well as the robustness and the efficiency of the complete algorithm.

  7. Consistent quadrupole-octupole collective model

    NASA Astrophysics Data System (ADS)

    Dobrowolski, A.; Mazurek, K.; Góźdź, A.

    2016-11-01

    Within this work we present a consistent approach to quadrupole-octupole collective vibrations coupled with the rotational motion. A realistic collective Hamiltonian with variable mass-parameter tensor and potential obtained through the macroscopic-microscopic Strutinsky-like method with particle-number-projected BCS (Bardeen-Cooper-Schrieffer) approach in full vibrational and rotational, nine-dimensional collective space is diagonalized in the basis of projected harmonic oscillator eigensolutions. This orthogonal basis of zero-, one-, two-, and three-phonon oscillator-like functions in vibrational part, coupled with the corresponding Wigner function is, in addition, symmetrized with respect to the so-called symmetrization group, appropriate to the collective space of the model. In the present model it is D4 group acting in the body-fixed frame. This symmetrization procedure is applied in order to provide the uniqueness of the Hamiltonian eigensolutions with respect to the laboratory coordinate system. The symmetrization is obtained using the projection onto the irreducible representation technique. The model generates the quadrupole ground-state spectrum as well as the lowest negative-parity spectrum in 156Gd nucleus. The interband and intraband B (E 1 ) and B (E 2 ) reduced transition probabilities are also calculated within those bands and compared with the recent experimental results for this nucleus. Such a collective approach is helpful in searching for the fingerprints of the possible high-rank symmetries (e.g., octahedral and tetrahedral) in nuclear collective bands.

  8. Generalized arc consistency for global cardinality constraint

    SciTech Connect

    Regin, J.C.

    1996-12-31

    A global cardinality constraint (gcc) is specified in terms of a set of variables X = (x{sub 1},..., x{sub p}) which take their values in a subset of V = (v{sub 1},...,v{sub d}). It constrains the number of times a value v{sub i} {epsilon} V is assigned to a variable in X to be in an interval [l{sub i}, c{sub i}]. Cardinality constraints have proved very useful in many real-life problems, such as scheduling, timetabling, or resource allocation. A gcc is more general than a constraint of difference, which requires each interval to be. In this paper, we present an efficient way of implementing generalized arc consistency for a gcc. The algorithm we propose is based on a new theorem of flow theory. Its space complexity is O({vert_bar}X{vert_bar} {times} {vert_bar}V{vert_bar}) and its time complexity is O({vert_bar}X{vert_bar}{sup 2} {times} {vert_bar}V{vert_bar}). We also show how this algorithm can efficiently be combined with other filtering techniques.

  9. Mining GO annotations for improving annotation consistency.

    PubMed

    Faria, Daniel; Schlicker, Andreas; Pesquita, Catia; Bastos, Hugo; Ferreira, António E N; Albrecht, Mario; Falcão, André O

    2012-01-01

    Despite the structure and objectivity provided by the Gene Ontology (GO), the annotation of proteins is a complex task that is subject to errors and inconsistencies. Electronically inferred annotations in particular are widely considered unreliable. However, given that manual curation of all GO annotations is unfeasible, it is imperative to improve the quality of electronically inferred annotations. In this work, we analyze the full GO molecular function annotation of UniProtKB proteins, and discuss some of the issues that affect their quality, focusing particularly on the lack of annotation consistency. Based on our analysis, we estimate that 64% of the UniProtKB proteins are incompletely annotated, and that inconsistent annotations affect 83% of the protein functions and at least 23% of the proteins. Additionally, we present and evaluate a data mining algorithm, based on the association rule learning methodology, for identifying implicit relationships between molecular function terms. The goal of this algorithm is to assist GO curators in updating GO and correcting and preventing inconsistent annotations. Our algorithm predicted 501 relationships with an estimated precision of 94%, whereas the basic association rule learning methodology predicted 12,352 relationships with a precision below 9%.

  10. A Consistent Phylogenetic Backbone for the Fungi

    PubMed Central

    Ebersberger, Ingo; de Matos Simoes, Ricardo; Kupczok, Anne; Gube, Matthias; Kothe, Erika; Voigt, Kerstin; von Haeseler, Arndt

    2012-01-01

    The kingdom of fungi provides model organisms for biotechnology, cell biology, genetics, and life sciences in general. Only when their phylogenetic relationships are stably resolved, can individual results from fungal research be integrated into a holistic picture of biology. However, and despite recent progress, many deep relationships within the fungi remain unclear. Here, we present the first phylogenomic study of an entire eukaryotic kingdom that uses a consistency criterion to strengthen phylogenetic conclusions. We reason that branches (splits) recovered with independent data and different tree reconstruction methods are likely to reflect true evolutionary relationships. Two complementary phylogenomic data sets based on 99 fungal genomes and 109 fungal expressed sequence tag (EST) sets analyzed with four different tree reconstruction methods shed light from different angles on the fungal tree of life. Eleven additional data sets address specifically the phylogenetic position of Blastocladiomycota, Ustilaginomycotina, and Dothideomycetes, respectively. The combined evidence from the resulting trees supports the deep-level stability of the fungal groups toward a comprehensive natural system of the fungi. In addition, our analysis reveals methodologically interesting aspects. Enrichment for EST encoded data—a common practice in phylogenomic analyses—introduces a strong bias toward slowly evolving and functionally correlated genes. Consequently, the generalization of phylogenomic data sets as collections of randomly selected genes cannot be taken for granted. A thorough characterization of the data to assess possible influences on the tree reconstruction should therefore become a standard in phylogenomic analyses. PMID:22114356

  11. Beam Trail Tracking at Fermilab

    SciTech Connect

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

    2015-01-01

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

  12. Light beam frequency comb generator

    DOEpatents

    Priatko, G.J.; Kaskey, J.A.

    1992-11-24

    A light beam frequency comb generator uses an acousto-optic modulator to generate a plurality of light beams with frequencies which are uniformly separated and possess common noise and drift characteristics. A well collimated monochromatic input light beam is passed through this modulator to produce a set of both frequency shifted and unshifted optical beams. An optical system directs one or more frequency shifted beams along a path which is parallel to the path of the input light beam such that the frequency shifted beams are made incident on the modulator proximate to but separated from the point of incidence of the input light beam. After the beam is thus returned to and passed through the modulator repeatedly, a plurality of mutually parallel beams are generated which are frequency-shifted different numbers of times and possess common noise and drift characteristics. 2 figs.

  13. Light beam frequency comb generator

    DOEpatents

    Priatko, Gordon J.; Kaskey, Jeffrey A.

    1992-01-01

    A light beam frequency comb generator uses an acousto-optic modulator to generate a plurality of light beams with frequencies which are uniformly separated and possess common noise and drift characteristics. A well collimated monochromatic input light beam is passed through this modulator to produce a set of both frequency shifted and unshifted optical beams. An optical system directs one or more frequency shifted beams along a path which is parallel to the path of the input light beam such that the frequency shifted beams are made incident on the modulator proximate to but separated from the point of incidence of the input light beam. After the beam is thus returned to and passed through the modulator repeatedly, a plurality of mutually parallel beams are generated which are frequency-shifted different numbers of times and possess common noise and drift characteristics.

  14. Beam Characterization at the Neutron Radiography Facility

    SciTech Connect

    Sarah Morgan; Jeffrey King

    2013-01-01

    The quality of a neutron imaging beam directly impacts the quality of radiographic images produced using that beam. Fully characterizing a neutron beam, including determination of the beam’s effective length-to-diameter ratio, neutron flux profile, energy spectrum, image quality, and beam divergence, is vital for producing quality radiographic images. This project characterized the east neutron imaging beamline at the Idaho National Laboratory Neutron Radiography Reactor (NRAD). The experiments which measured the beam’s effective length-to-diameter ratio and image quality are based on American Society for Testing and Materials (ASTM) standards. An analysis of the image produced by a calibrated phantom measured the beam divergence. The energy spectrum measurements consist of a series of foil irradiations using a selection of activation foils, compared to the results produced by a Monte Carlo n-Particle (MCNP) model of the beamline. Improvement of the existing NRAD MCNP beamline model includes validation of the model’s energy spectrum and the development of enhanced image simulation methods. The image simulation methods predict the radiographic image of an object based on the foil reaction rate data obtained by placing a model of the object in front of the image plane in an MCNP beamline model.

  15. Sound practices for consistent human visual inspection.

    PubMed

    Melchore, James A

    2011-03-01

    Numerous presentations and articles on manual inspection of pharmaceutical drug products have been released, since the pioneering articles on inspection by Knapp and associates Knapp and Kushner (J Parenter Drug Assoc 34:14, 1980); Knapp and Kushner (Bull Parenter Drug Assoc 34:369, 1980); Knapp and Kushner (J Parenter Sci Technol 35:176, 1981); Knapp and Kushner (J Parenter Sci Technol 37:170, 1983). This original work by Knapp and associates provided the industry with a statistical means of evaluating inspection performance. This methodology enabled measurement of individual inspector performance, performance of the entire inspector pool and provided basic suggestions for the conduct of manual inspection. Since that time, numerous subject matter experts (SMEs) have presented additional valuable information for the conduct of manual inspection Borchert et al. (J Parenter Sci Technol 40:212, 1986); Knapp and Abramson (J Parenter Sci Technol 44:74, 1990); Shabushnig et al. (1994); Knapp (1999); Knapp (2005); Cherris (2005); Budd (2005); Barber and Thomas (2005); Knapp (2005); Melchore (2007); Leversee and Ronald (2007); Melchore (2009); Budd (2007); Borchert et al. (1986); Berdovich (2005); Berdovich (2007); Knapp (2007); Leversee and Shabushing (2009); Budd (2009). Despite this abundance of knowledge, neither government regulations nor the multiple compendia provide more than minimal guidance or agreement for the conduct of manual inspection. One has to search the literature for useful information that has been published by SMEs in the field of Inspection. The purpose of this article is to restate the sound principles proclaimed by SMEs with the hope that they serve as a useful guideline to bring greater consistency to the conduct of manual inspection.

  16. Precession/Nutation Solution Consistent With

    NASA Astrophysics Data System (ADS)

    Planetary Theory, The, , General

    2006-08-01

    Institute of Applied Astronomy of RAS, St.Petersburg, Russia In the present paper the equations of the translatory motion of the major planets and the Moon and the Poisson equations of the Earth's rotation in Euler parameters are reduced to the secular system describing the evolution of the planetary and lunar orbits (independent of the Earth's rotation) and the evolution of the Earth's rotation (depending on the planetary and lunar evolution). Hence, the theory of the Earth's rotation is presented by means of the series in powers of the evolutionary variables with quasi-periodic coefficients. The behaviour of the evolutionary variables is governed by an autonomous secular system. For the Poisson equations of the Earth's rotation the trigonometric solution of the secular system is of interest to study evolution of motion and rotation (in astronomical climatology, for instance).Our main conclusion is that there is no principal difficulty to find solution of the Earth's rotation problem consistent with the general planetary theory (V.A.Brumberg, 1995) adequate to the present observation accuracy. For this purpose the general case of the rigid-body Earth's rotation adequate to SMART solution (Bretagnon et al., 1998).should be considered. All actual calculations were performed using a Poisson series processor (Ivanova, 1995). References 1. Bretagnon P., Francou G., Rocher P., and Simon J.L.: 1998,`SMART97: A new solution for the rotation of the rigid Earth', Astron. Astrophys, 329, 329 2. Brumberg V.A.: 1995, `Analytical Techniques of Celestial Mechanics', Springer, Heidelberg 3. Ivanova T.V.: 1996, `PSP: A New Poisson Series Processor',In: Dynamics, Ephemerides and Astrometry of the Solar System (eds.S. Ferraz-Mello, B. Morando and J.-E. Arlot), Kluwer, 283

  17. Improving electrofishing catch consistency by standardizing power

    USGS Publications Warehouse

    Burkhardt, Randy W.; Gutreuter, Steve

    1995-01-01

    The electrical output of electrofishing equipment is commonly standardized by using either constant voltage or constant amperage, However, simplified circuit and wave theories of electricity suggest that standardization of power (wattage) available for transfer from water to fish may be critical for effective standardization of electrofishing. Electrofishing with standardized power ensures that constant power is transferable to fish regardless of water conditions. The in situ performance of standardized power output is poorly known. We used data collected by the interagency Long Term Resource Monitoring Program (LTRMP) in the upper Mississippi River system to assess the effectiveness of standardizing power output. The data consisted of 278 electrofishing collections, comprising 9,282 fishes in eight species groups, obtained during 1990 from main channel border, backwater, and tailwater aquatic areas in four reaches of the upper Mississippi River and one reach of the Illinois River. Variation in power output explained an average of 14.9% of catch variance for night electrofishing and 12.1 % for day electrofishing. Three patterns in catch per unit effort were observed for different species: increasing catch with increasing power, decreasing catch with increasing power, and no power-related pattern. Therefore, in addition to reducing catch variation, controlling power output may provide some capability to select particular species. The LTRMP adopted standardized power output beginning in 1991; standardized power output is adjusted for variation in water conductivity and water temperature by reference to a simple chart. Our data suggest that by standardizing electrofishing power output, the LTRMP has eliminated substantial amounts of catch variation at virtually no additional cost.

  18. Comparative exoplanetology with consistent retrieval methods

    NASA Astrophysics Data System (ADS)

    Barstow, Joanna Katy; Aigrain, Suzanne; Irwin, Patrick Gerard Joseph; Sing, David

    2016-10-01

    The number of hot Jupiters with broad wavelength spectroscopic data has finally become large enough to make comparative planetology a reasonable proposition. New results presented by Sing et al. (2016) showcase ten hot Jupiters with spectra from the Hubble Space Telescope and photometry from Spitzer, providing insights into the presence of clouds and hazes.Spectral retrieval methods allow interpretation of exoplanet spectra using simple models, with minimal prior assumptions. This is particularly useful for exotic exoplanets, for which we may not yet fully understand the physical processes responsible for their atmospheric characteristics. Consistent spectral retrieval of a range of exoplanets can allow robust comparisons of their derived atmospheric properties.I will present a retrieval analysis using the NEMESIS code (Irwin et al. 2008) of the ten hot Jupiter spectra presented by Sing et al. (2016). The only distinctive aspects of the model for each planet are the mass and radius, and the temperature range explored. All other a priori model parameters are common to all ten objects. We test a range of cloud and haze scenarios, which include: Rayleigh-dominated and grey clouds; different cloud top pressures; and both vertically extended and vertically confined clouds.All ten planets, with the exception of WASP-39b, can be well represented by models with at least some haze or cloud. Our analysis of cloud properties has uncovered trends in cloud top pressure, vertical extent and particle size with planet equilibrium temperature. Taken together, we suggest that these trends indicate condensation and sedimentation of at least two different cloud species across planets of different temperatures, with condensates forming higher up in hotter atmospheres and moving progressively further down in cooler planets.Sing, D. et al. (2016), Nature, 529, 59Irwin, P. G. J. et al. (2008), JQSRT, 109, 1136

  19. Geometrically consistent approach to stochastic DBI inflation

    SciTech Connect

    Lorenz, Larissa; Martin, Jerome; Yokoyama, Jun'ichi

    2010-07-15

    Stochastic effects during inflation can be addressed by averaging the quantum inflaton field over Hubble-patch-sized domains. The averaged field then obeys a Langevin-type equation into which short-scale fluctuations enter as a noise term. We solve the Langevin equation for an inflaton field with a Dirac-Born-Infeld (DBI) kinetic term perturbatively in the noise and use the result to determine the field value's probability density function (PDF). In this calculation, both the shape of the potential and the warp factor are arbitrary functions, and the PDF is obtained with and without volume effects due to the finite size of the averaging domain. DBI kinetic terms typically arise in string-inspired inflationary scenarios in which the scalar field is associated with some distance within the (compact) extra dimensions. The inflaton's accessible range of field values therefore is limited because of the extra dimensions' finite size. We argue that in a consistent stochastic approach the inflaton's PDF must vanish for geometrically forbidden field values. We propose to implement these extra-dimensional spatial restrictions into the PDF by installing absorbing (or reflecting) walls at the respective boundaries in field space. As a toy model, we consider a DBI inflaton between two absorbing walls and use the method of images to determine its most general PDF. The resulting PDF is studied in detail for the example of a quartic warp factor and a chaotic inflaton potential. The presence of the walls is shown to affect the inflaton trajectory for a given set of parameters.

  20. Movement consistency during repetitive tool use action

    PubMed Central

    Baber, Chris

    2017-01-01

    The consistency and repeatability of movement patterns has been of long-standing interest in locomotor biomechanics, but less well explored in other domains. Tool use is one of such a domain; while the complex dynamics of the human-tool-environment system have been approached from various angles, to date it remains unknown how the rhythmicity of repetitive tool-using action emerges. To examine whether the spontaneously adopted movement frequency is a variable susceptible to individual execution approaches or emerges as constant behaviour, we recorded sawing motion across a range of 14 experimental conditions using various manipulations. This was compared to free and pantomimed arm movements. We found that a mean (SD) sawing frequency of 2.0 (0.4) Hz was employed across experimental conditions. Most experimental conditions did not significantly affect the sawing frequency, signifying the robustness of this spontaneously emerging movement. Free horizontal arm translation and miming of sawing was performed at half the movement frequency with more than double the excursion distance, showing that not all arm movements spontaneously emerge at the observed sawing parameters. Observed movement frequencies across all conditions could be closely predicted from movement time reference data for generic arm movements found in the Methods Time Measurement literature, highlighting a generic biomechanical relationship between the time taken for a given distance travelled underlying the observed behaviour. We conclude that our findings lend support to the hypothesis that repetitive movements during tool use are executed according to generic and predictable musculoskeletal mechanics and constraints, albeit in the context of the general task (sawing) and environmental constraints such as friction, rather than being subject to task-specific control or individual cognitive schemata. PMID:28278273

  1. Characterization of Laser Beam Quality.

    DTIC Science & Technology

    1982-12-01

    proposed a lens-less method to determine beam divergence of Gaussian -shaped laser beams. The propagation of a Gaussian beam is shown in figure 8. Given...irradiance profile of laser beams, a numerical model was developed to simulate the propagation of nondif- fraction-limited laser beams. The function of...In developing the computer model , the incident field 30 *°" [(x, 12. :h e--27,1, is assumed to be Gaussian in intensity, truncated by an aper- ture

  2. Review of nondiffracting Bessel beams

    NASA Technical Reports Server (NTRS)

    Lapointe, Michael R.

    1991-01-01

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

  3. LHC beam-beam compensation studies at RHIC

    SciTech Connect

    Fischer,W.; Abreu, N.; Calaga, R.; Robert-Demolaize, G.; Luo, Y.; Montag, C.

    2009-05-04

    Long-range and head-on beam-beam effects are expected to limit the LHC performance with design parameters. To mitigate long-range effects current carrying wires parallel to the beam were proposed. Two such wires are installed in RHIC where they allow studying the effect of strong long-range beam-beam effects, as well as the compensation of a single long-range interaction. The tests provide benchmark data for simulations and analytical treatments. To reduce the head-on beam-beam effect electron lenses were proposed for both the LHC and RHIC. We present the experimental long-range beam-beam program and report on head-on compensations studies at RHIC, which are based on simulations.

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

    SciTech Connect

    Luo, Y.; Fischer, W.; White, S.

    2015-06-24

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

  5. Electron beam polarimetry

    SciTech Connect

    Sinclair, C.K.

    1998-12-01

    Along with its well known charge and mass, the electron also carries an intrinsic angular momentum, or {ital spin}. The rules of quantum mechanics allow us to measure only the probability that the electron spin is in one of two allowed spin states. When a beam carries a net excess of electrons in one of these two allowed spin states, the beam is said to be {ital polarized}. The beam polarization may be measured by observing a sufficient number of electrons scattered by a spin-dependent interaction. For electrons, the useful scattering processes involve Coulomb scattering by heavy nuclei, or scattering from either polarized photons or other polarized electrons (known as Mott, Compton, and Mo/ller scattering, respectively). In this tutorial, we will briefly review how beam polarization is measured through a general scattering process, followed by a discussion of how the three scattering processes above are used to measure electron beam polarization. Descriptions of electron polarimeters based on the three scattering processes will be given. {copyright} {ital 1998 American Institute of Physics.}

  6. Electron beam polarimetry

    NASA Astrophysics Data System (ADS)

    Sinclair, Charles K.

    1998-12-01

    Along with its well known charge and mass, the electron also carries an intrinsic angular momentum, or spin. The rules of quantum mechanics allow us to measure only the probability that the electron spin is in one of two allowed spin states. When a beam carries a net excess of electrons in one of these two allowed spin states, the beam is said to be polarized. The beam polarization may be measured by observing a sufficient number of electrons scattered by a spin-dependent interaction. For electrons, the useful scattering processes involve Coulomb scattering by heavy nuclei, or scattering from either polarized photons or other polarized electrons (known as Mott, Compton, and Mo/ller scattering, respectively). In this tutorial, we will briefly review how beam polarization is measured through a general scattering process, followed by a discussion of how the three scattering processes above are used to measure electron beam polarization. Descriptions of electron polarimeters based on the three scattering processes will be given.

  7. ICFA Beam Dynamics Newsletter

    SciTech Connect

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

    2012-07-01

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

  8. BEAM Technology Flight Demonstration

    NASA Technical Reports Server (NTRS)

    Wang, David

    2005-01-01

    As technologies advance, their growing complexity makes them harder to maintain. Detection methods for isolating and identifying impending problems are needed to balance this complexity. Through comparison of signal pairs from onboard sensors, the Beacon-based Exception Analysis For Multimissions (BEAM) algorithm can identify and help classify deviations in system operation from a data-trained statistical model. The goal of this task is to mature BEAM and validate its performance on a flying test bed. A series of F-18 flight demonstrations with BEAM monitoring engine parameters in real time was used to demonstrate in-the-field readiness. Captured F-18 and simulated F-18 engine data were used in model creation and training. The algorithm was then ported to the embedded system with a data buffering, file writing, and data-time-stamp monitoring shell to reduce the impact of embedded system faults on BEAM'S ability to correctly identify engine faults. Embedded system testing identified hardware related restrictions and contributed to iterative improvements in the code's runtime performance. The system was flown with forced engine flameouts and other pilot induced faults to simulate operation out of the norm. Successful detection of these faults, confirmed through post-flight data analysis, helped BEAM achieve TRL6.

  9. Dynamics of elastic nonlinear rotating composite beams with embedded actuators

    NASA Astrophysics Data System (ADS)

    Ghorashi, Mehrdaad

    2009-08-01

    A comprehensive study of the nonlinear dynamics of composite beams is presented. The study consists of static and dynamic solutions with and without active elements. The static solution provides the initial conditions for the dynamic analysis. The dynamic problems considered include the analyses of clamped (hingeless) and articulated (hinged) accelerating rotating beams. Numerical solutions for the steady state and transient responses have been obtained. It is shown that the transient solution of the nonlinear formulation of accelerating rotating beam converges to the steady state solution obtained by the shooting method. The effect of perturbing the steady state solution has also been calculated and the results are shown to be compatible with those of the accelerating beam analysis. Next, the coupled flap-lag rigid body dynamics of a rotating articulated beam with hinge offset and subjected to aerodynamic forces is formulated. The solution to this rigid-body problem is then used, together with the finite difference method, in order to produce the nonlinear elasto-dynamic solution of an accelerating articulated beam. Next, the static and dynamic responses of nonlinear composite beams with embedded Anisotropic Piezo-composite Actuators (APA) are presented. The effect of activating actuators at various directions on the steady state force and moments generated in a rotating composite beam has been presented. With similar results for the transient response, this analysis can be used in controlling the response of adaptive rotating beams.

  10. Beam Profile Measurement in MTA Beam Line for High Pressure RF Cavity Beam Test

    SciTech Connect

    Jana, M.R.; Bross, A.; Chung, M.; Greer, S.; Johnstone, C.; Kobilarcik, T.; Koizumi, G.; Leonova, M.; Moretti, A.; Popovic, M.; Schwartz, T.; /Fermilab /IIT, Chicago /PDT, Torino

    2012-05-15

    Recent High Pressure RF (HPRF) cavity experiment at MuCool Test Area (MTA) has used 400 MeV Linac proton beam to study the beam loading effect. When the energetic proton beam passes through the cavity, it ionizes the inside gas and produces the electrons. These electrons consume RF power inside the cavity. Number of electrons produced per cm inside the cavity (at 950 psi Hydrogen gas) per incident proton is {approx} 1200. The measurement of beam position and profile are necessary. MTA is flammable gas (Hydrogen) hazard zone so we have developed a passive beam diagnostic instrument using Chromox-6 scintillation screen and CCD camera. This paper presents quantitative information about beam position and beam profile. Neutral density filter was used to avoid saturation of CCD camera. Image data is filtered and fitted with Gaussian function to compute the beam size. The beam profile obtained from scintillation screen shall be compared with multi-wire beam profile.

  11. Optical Device for Converting a Laser Beam into Two Co-aligned but Oppositely Directed Beams

    NASA Technical Reports Server (NTRS)

    Jennings, Donald

    2013-01-01

    Optical systems consisting of a series of optical elements require alignment from the input end to the output end. The optical elements can be mirrors, lenses, sources, detectors, or other devices. Complex optical systems are often difficult to align from end-to-end because the alignment beam must be inserted at one end in order for the beam to traverse the entire optical path to the other end. The ends of the optical train may not be easily accessible to the alignment beam. Typically, when a series of optical elements is to be aligned, an alignment laser beam is inserted into the optical path with a pick-off mirror at one end of the series of elements. But it may be impossible to insert the beam at an end-point. It can be difficult to locate the pick-off mirror at the desired position because there is not enough space, there is no mounting surface, or the location is occupied by a source, detector, or other component. Alternatively, the laser beam might be inserted at an intermediate location (not at an end-point) and sent, first in one direction and then the other, to the opposite ends of the optical system for alignment. However, in this case, alignment must be performed in two directions and extra effort is required to co-align the two beams to make them parallel and coincident, i.e., to follow the same path as an end-to-end beam. An optical device has been developed that accepts a laser beam as input and produces two co-aligned, but counter-propagating beams. In contrast to a conventional alignment laser placed at one end of the optical path, this invention can be placed at a convenient position within the optical train and aligned to send its two beams simultaneously along precisely opposite paths that, taken together, trace out exactly the same path as the conventional alignment laser. This invention allows the user the freedom to choose locations within the optical train for placement of the alignment beam. It is also self-aligned by design and requires

  12. On damping mechanisms in beams

    NASA Technical Reports Server (NTRS)

    Banks, H. T.; Inman, D. J.

    1989-01-01

    A partial differential equation model of a cantilevered beam with a tip mass at its free end is used to study damping in a composite. Four separate damping mechanisms consisting of air damping, strain rate damping, spatial hysteresis and time hysteresis are considered experimentally. Dynamic tests were performed to produce time histories. The time history data is then used along with an approximate model to form a sequence of least squares problems. The solution of the least squares problem yields the estimated damping coefficients. The resulting experimentally determined analytical model is compared with the time histories via numerical simulation of the dynamic response. The procedure suggested here is compared with a standard modal damping ratio model commonly used in experimental modal analysis.

  13. On damping mechanisms in beams

    NASA Technical Reports Server (NTRS)

    Banks, H. T.; Inman, D. J.

    1991-01-01

    A partial differential equation model of a cantilevered beam with a tip mass at its free end is used to study damping in a composite. Four separate damping mechanisms consisting of air damping, strain rate damping, spatial hysteresis and time hysteresis are considered experimentally. Dynamic tests were performed to produce time histories. The time history data is then used along with an approximate model to form a sequence of least squares problems. The solution of the least squares problem yields the estimated damping coefficients. The resulting experimentally determined analytical model is compared with the time histories via numerical simulation of the dynamic response. The procedure suggested here is compared with a standard modal damping ratio model commonly used in experimental modal analysis.

  14. QCD tests with polarized beams

    SciTech Connect

    Maruyama, Takashi; SLD Collaboration

    1996-09-01

    The authors present three QCD studies performed by the SLD experiment at SLAC, utilizing the highly polarized SLC electron beam. They examined particle production differences in light quark and antiquark hemispheres, and observed more high momentum baryons and K{sup {minus}}`s than antibaryons and K{sup +}`s in quark hemispheres, consistent with the leading particle hypothesis. They performed a search for jet handedness in light q- and {anti q}-jets. Assuming Standard Model values of quark polarization in Z{sup 0} decays, they have set an improved upper limit on the analyzing power of the handedness method. They studied the correlation between the Z{sup 0} spin and the event-plane orientation in polarized Z{sup 0} decays into three jets.

  15. Improved Beam Diagnostic Spatial Calibration Using In-Situ Measurements of Beam Emission

    NASA Astrophysics Data System (ADS)

    Chrystal, C.; Burrell, K. H.; Pace, D. C.; Grierson, B. A.; Pablant, N. A.

    2014-10-01

    A new technique has been developed for determining the measurement geometry of the charge exchange recombination spectroscopy diagnostic (CER) on DIII-D. This technique removes uncertainty in the measurement geometry related to the position of the neutral beams when they are injecting power. This has been accomplished by combining standard measurements that use in-vessel calibration targets with spectroscopic measurements of Doppler shifted and Stark split beam emission to fully describe the neutral beam positions and CER views. A least squares fitting routine determines the measurement geometry consistent with all the calibration data. The use of beam emission measurements allows the position of the neutral beams to be determined in-situ by the same views that makeup the CER diagnostic. Results indicate that changes in the measurement geometry are required to create a consistent set of calibration measurements. However, changes in quantities derived from the geometry, e.g. ion temperature gradient and poloidal rotation, are small. Work supported by the US DOE under DE-FG02-07ER54917, DE-FC02-04ER54698, and DE-AC02-09H11466.

  16. Ultra-thin anisotropic metasurface for polarized beam splitting and reflected beam steering applications

    NASA Astrophysics Data System (ADS)

    Guo, Wenlong; Wang, Guangming; Li, Tangjing; Li, Haipeng; Zhuang, Yaqiang; Hou, Haisheng

    2016-10-01

    In this paper, we propose a polarization beam splitter utilizing an ultra-thin anisotropic metasurface. The proposed anisotropic element is composed of triple-layered rectangular patches spaced with double-layered dielectric isolators. By tailoring the metallic patches, the cell is capable of transmitting x-polarized waves efficiently and reflecting y-polarized beams with almost 100% efficiency at 15 GHz. In addition to this, the reflected phases can be modulated by adjusting the size of the element, which contributes to beam steering in reflection mode. By assigning gradient phases on the metasurface, the constructed sample has the ability to refract x-polarized waves normally and reflect y-polarized beams anomalously. For verification, a sample with a size of 240 × 240 mm2 is fabricated and measured. Consistent numerical and experimental results have both validated the efficiently anomalous reflection for y-polarized waves and normal refraction for x-polarized beams operating from 14.6-15.4 GHz. Furthermore, the proposed sample has a thickness of 0.1λ at 15 GHz, which provides a promising approach for steering and splitting beams in a compact size.

  17. Beam Profile Monitor With Accurate Horizontal And Vertical Beam Profiles

    DOEpatents

    Havener, Charles C [Knoxville, TN; Al-Rejoub, Riad [Oak Ridge, TN

    2005-12-26

    A widely used scanner device that rotates a single helically shaped wire probe in and out of a particle beam at different beamline positions to give a pair of mutually perpendicular beam profiles is modified by the addition of a second wire probe. As a result, a pair of mutually perpendicular beam profiles is obtained at a first beamline position, and a second pair of mutually perpendicular beam profiles is obtained at a second beamline position. The simple modification not only provides more accurate beam profiles, but also provides a measurement of the beam divergence and quality in a single compact device.

  18. Symplectic multiparticle tracking model for self-consistent space-charge simulation

    NASA Astrophysics Data System (ADS)

    Qiang, Ji

    2017-01-01

    Symplectic tracking is important in accelerator beam dynamics simulation. So far, to the best of our knowledge, there is no self-consistent symplectic space-charge tracking model available in the accelerator community. In this paper, we present a two-dimensional and a three-dimensional symplectic multiparticle spectral model for space-charge tracking simulation. This model includes both the effect from external fields and the effect of self-consistent space-charge fields using a split-operator method. Such a model preserves the phase space structure and shows much less numerical emittance growth than the particle-in-cell model in the illustrative examples.

  19. Beamed energy propulsion

    NASA Technical Reports Server (NTRS)

    Shoji, James M.

    1992-01-01

    Beamed energy concepts offer an alternative for an advanced propulsion system. The use of a remote power source reduces the weight of the propulsion system in flight and this, combined with the high performance, provides significant payload gains. Within the context of this study's baseline scenario, two beamed energy propulsion concepts are potentially attractive: solar thermal propulsion and laser thermal propulsion. The conceived beamed energy propulsion devices generally provide low thrust (tens of pounds to hundreds of pounds); therefore, they are typically suggested for cargo transportation. For the baseline scenario, these propulsion system can provide propulsion between the following nodes: (1) low Earth orbit to geosynchronous Earth orbit; (2) low Earth orbit to low lunar orbit; (3) low lunar orbit to low Mars orbit--only solar thermal; and (4) lunar surface to low lunar orbit--only laser thermal.

  20. Grazing incidence beam expander

    NASA Astrophysics Data System (ADS)

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

    1985-01-01

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

  1. A fan beam model for radio pulsars. I. Observational evidence

    SciTech Connect

    Wang, H. G.; Pi, F. P.; Deng, C. L.; Wen, S. Q.; Ye, F.; Guan, K.Y.; Liu, Y.; Xu, L. Q.; Zheng, X. P.

    2014-07-01

    We propose a novel beam model for radio pulsars based on the scenario that the broadband and coherent emission from secondary relativistic particles, as they move along a flux tube in a dipolar magnetic field, form a radially extended sub-beam with unique properties. The whole radio beam may consist of several sub-beams, forming a fan-shaped pattern. When only one or a few flux tubes are active, the fan beam becomes very patchy. This model differs essentially from the conal beam models with respect to the beam structure and predictions on the relationship between pulse width and impact angle β (the angle between the line of sight and the magnetic pole) and the relationship between emission intensity and beam angular radius. The evidence for this model comes from the observed patchy beams of precessional binary pulsars and three statistical relationships found for a sample of 64 pulsars, of which β were mostly constrained by fitting polarization position angle data with the rotation vector model. With appropriate assumptions, the fan beam model can reproduce the relationship between 10% peak pulse width and |β|, the anticorrelation between the emission intensity and |β|, and the upper boundary line in the scatter plot of |β| versus pulsar distance. An extremely patchy beam model with the assumption of narrowband emission from one or a few flux tubes is studied and found unlikely to be a general model. The implications of the fan beam model for the studies on radio and gamma-ray pulsar populations and radio polarization are discussed.

  2. Adjustable hollow-cone output x-ray beam from an ellipsoidal monocapillary with a pinhole and a beam stop.

    PubMed

    Sun, Xue-Peng; Liu, Zhi-Gou; Yi, Long-Tao; Sun, Wei-Yun; Li, Fang-Zou; Jiang, Bo-Wen; Ma, Yong-Zhong; Sun, Tian-Xi

    2015-12-10

    A combined shading system (CSS) consisting of a beam stop and a pinhole is proposed to be used between an ellipsoidal monocapillary (EM) and a conventional laboratory x-ray source to obtain an adjustable hollow-cone output beam for different experiments with no need for changing the EM. The CSS can change the incident x-ray beam on the EM by adjusting the position of the beam stop and the pinhole, with the corresponding change of the output beam of the EM. In this study, the adjustable hollow-cone output x-ray beam of an 80-mm-long EM with a CSS was studied in detail with a laboratory Cu x-ray generator with a focal spot diameter of 50 μm. The adjustable range of the focal spot size of the EM was from 8.6 to 58.7 μm. The adjustable range of the gain of the focal spot of the EM was from 0 to 1350. The beam divergence of the hollow-cone output beam of the EM ranged from 6 to 16.75 mrad. The illumination angle of the hollow-cone output beam of the EM ranged from 0 to 5.95 mrad. In addition, the potential application of the proposed adjusting method in testing the performance of the EM is briefly discussed.

  3. Beam shaping to provide round and square-shaped beams in optical systems of high-power lasers

    NASA Astrophysics Data System (ADS)

    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.

  4. Size-consistent self-consistent configuration interaction from a complete active space

    NASA Astrophysics Data System (ADS)

    Ben Amor, Nadia; Maynau, Daniel

    1998-04-01

    The size-consistent self-consistent (SC) 2 method is based on intermediate Hamiltonians and ensures size-extensivity of any configuration interaction (CI) by correcting its diagonal elements. In this work, an (SC) 2 dressing is proposed on a complete active space SDCI. This approach yields a more efficient code which can treat larger multireference problems. Tests are proposed on the potential energy curve of F 2, the bond stretching of water and the inclusion of an Be atom in the H 2 molecule. Comparisons with approximate methods such as average quadratic coupled cluster (AQCC) are presented. AQCC appears as a good approximation to (SC) 2.

  5. Primer on Beam Optics

    DTIC Science & Technology

    2007-11-02

    Inc. San Diego, California Table of Contents Page 1 . Introduction 1 1.1 Organization of Primer 1 1.2 Introduction to Neutral Particle Beam...Optical Systems 3 2. Fundamentals of Charged Particle Optics 10 2.1 Introduction 1 ° 2.2 Phase Space and Nonlinear Motion 10 2.3 Linear Maps 22 2.4...102 Figures Figure Pag© 1 . Generic Neutral Particle Beam Device 4 2. An orthogonal three dimensional coordinate system 11 3. Trajectory of a

  6. Dealing with megawatt beams

    SciTech Connect

    Mokhov, N.V.; /Fermilab

    2010-08-01

    The next generation of accelerators for MegaWatt proton, electron and heavy-ion beams puts unprecedented requirements on the accuracy of particle production predictions, the capability and reliability of the codes used in planning new accelerator facilities and experiments, the design of machine, target and collimation systems, detectors and radiation shielding and minimization of their impact on environment. Recent advances in code developments are described for the critical modules related to these challenges. Examples are given for the most demanding areas: targets, collimators, beam absorbers, radiation shielding, induced radioactivity and radiation damage.

  7. Composite beam builder

    NASA Technical Reports Server (NTRS)

    Poveromo, L. M.; Muench, W. K.; Marx, W.; Lubin, G.

    1981-01-01

    The building block approach to large space structures is discussed, and the progress made in constructing aluminum beams is noted. It is pointed out that composites will also be required in space structures because they provide minimal distortion characteristics during thermal transients. A composite beam builder currently under development is discussed, with attention given to cap forming and the fastening of cross-braces. The various composite materials being considered are listed, along with certain of their properties. The need to develop continuous forming stock up to 300 m long is stressed.

  8. Diamonds for beam instrumentation

    SciTech Connect

    Griesmayer, Erich

    2013-04-19

    Diamond is perhaps the most versatile, efficient and radiation tolerant material available for use in beam detectors with a correspondingly wide range of applications in beam instrumentation. Numerous practical applications have demonstrated and exploited the sensitivity of diamond to charged particles, photons and neutrons. In this paper, a brief description of a generic diamond detector is given and the interaction of the CVD diamond detector material with protons, electrons, photons and neutrons is presented. Latest results of the interaction of sCVD diamond with 14 MeV mono-energetic neutrons are shown.

  9. INTERACTION OF MUON BEAM WITH PLASMA DEVELOPED DURING IONIZATION COOLING

    SciTech Connect

    S. Ahmed, D. Kaplan, T. Roberts, L. Spentzouris, K. Beard

    2012-07-01

    Particle-in-cell simulations involving the interaction of muon beam (peak density 10{sup 18} m{sup 3}) with Li plasma (ionized medium) of density 10{sup 16}-10{sup 22} m{sup -3} have been performed. This study aimed to understand the effects of plasma on an incoming beam in order to explore scenario developed during the process of ionization cooling. The computer code takes into account the self-consistent electromagnetic effects of beam interacting with plasma. This study shows that the beam can pass through the plasma of densities four order of magnitude higher than its peak density. The low density plasmas are wiped out by the beam, however, the resonance is observed for densities of similar order. Study reveals the signature of plasma wakefield acceleration.

  10. Generation of fiber-based plasmonic Airy beam

    NASA Astrophysics Data System (ADS)

    Guan, Chunying; Ding, Ming; Shi, Jinhui; Wang, Pengfei; Hua, Ping; Brambilla, Gilberto; Yuan, Libo

    2014-05-01

    Compact all-fiber plasmonic Airy-like beam generator is demonstrated. A single slit and a 1D groove array were fabricated by focused ion beam (FIB) milling on the end facet of a single mode optical fiber. The single slit excites the surface plasmonic polaritons (SPPs), which are decoupled into free space by the groove array. The phase of decoupling SPPs is adjusted by the grooves position. Experimental generation of the single Airy-like beam has good consistency with theoretical predictions. The transverse acceleration and nondiffraction properties are observed. The presented plasmonic Airy-like beam generator is of importance to realize all-fiber optical trapping, beam shaping, and fiber integrated devices.

  11. Nonlinear Dynamics of Beam-driven TAEs in NSTX

    NASA Astrophysics Data System (ADS)

    Fu, Guoyong; Liu, Deyong; Wang, Feng

    2015-11-01

    Energetic particle modes and Alfvénic modes driven by super-Alfvénic beam ions were routinely observed in neutral beam heated plasmas on NSTX. These modes can significantly impact beam-ion transport, thus causing beam-ion redistribution and losses. Recent simulation results of TAEs show mode radial structure consistent with the reflectometer measurements of electron density fluctuations. In this paper we report on new simulations of multiple TAEs in NSTX plasmas using the M3D-K code. The results show strong interaction between TAEs and fishbone that either enhances or reduces saturation level of individual modes depending on mode number and other parameters. As beam ion beta increases beyond a threshold, mode saturation levels are found to increases sharply. Correspondingly the locally flattening regions merge together resulting in global particle transport and substantial particle loss. These results are similar to the TAE avalanche observed in NSTX.

  12. Specular and antispecular light beams.

    PubMed

    Partanen, Henri; Sharmin, Najnin; Tervo, Jani; Turunen, Jari

    2015-11-02

    We consider a class of spatially partially coherent light beams, which are generated by passing a Gaussian Schell-model beam though a wavefront-folding interferometer. In certain cases these beams are shape-invariant on propagation and can exhibit sharp internal structure with a central peak (specular beam) or a central dip (antispecular beam) whose dimensions depend on the spatial coherence area. Such beams are demonstrated experimentally and their cross-like distributions of the complex degree of spatial coherence are measured with a digital micromirror device.

  13. The cooling of particle beams

    SciTech Connect

    Sessler, A.M.

    1994-10-01

    A review is given of the various methods which can be employed for cooling particle beams. These methods include radiation damping, stimulated radiation damping, ionization cooling, stochastic cooling, electron cooling, laser cooling, and laser cooling with beam coupling. Laser Cooling has provided beams of the lowest temperatures, namely 1 mK, but only for ions and only for the longitudinal temperature. Recent theoretical work has suggested how laser cooling, with the coupling of beam motion, can be used to reduce the ion beam temperature in all three directions. The majority of this paper is devoted to describing laser cooling and laser cooling with beam coupling.

  14. EFFECTS OF TRANSFERSE BEAM SIZE IN BEAM POSITIONS MONITORS

    SciTech Connect

    S.S. KURENNOY

    2001-06-01

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

  15. High current beam transport with multiple beam arrays

    SciTech Connect

    Kim, C.H.

    1985-05-01

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

  16. Optimizing the electron beam parameters for head-on beam-beam compensation in RHIC

    SciTech Connect

    Luo, Y.; Fischer, W.; Pikin, A.; Gu, X.

    2011-03-28

    Head-on beam-beam compensation is adopted to compensate the large beam-beam tune spread from the protonproton interactions at IP6 and IP8 in the Relativistic Heavy Ion Collider (RHIC). Two e-lenses are being built and to be in stalled near IP10 in the end of 2011. In this article we perform numeric simulation to investigate the effect of the electron beam parameters on the proton dynamics. The electron beam parameters include its transverse profile, size, current, offset and random errors in them. In this article we studied the effect of the electron beam parameters on the proton dynamics. The electron beam parameters include its transverse shape, size, current, offset and their random errors. From the study, we require that the electron beam size can not be smaller than the proton beam's. And the random noise in the electron current should be better than 0.1%. The offset of electron beam w.r.t. the proton beam center is crucial to head-on beam-beam compensation. Its random errors should be below {+-}8{micro}m.

  17. Candlestick rubidium beam source

    NASA Astrophysics Data System (ADS)

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

    2000-09-01

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

  18. Beam current sensor

    DOEpatents

    Kuchnir, M.; Mills, F.E.

    1984-09-28

    A current sensor for measuring the dc component of a beam of charged particles employs a superconducting pick-up loop probe, with twisted superconducting leads in combination with a Superconducting Quantum Interference Device (SQUID) detector. The pick-up probe is in the form of a single-turn loop, or a cylindrical toroid, through which the beam is directed and within which a first magnetic flux is excluded by the Meisner effect. The SQUID detector acts as a flux-to-voltage converter in providing a current to the pick-up loop so as to establish a second magnetic flux within the electrode which nulls out the first magnetic flux. A feedback voltage within the SQUID detector represents the beam current of the particles which transit the pick-up loop. Meisner effect currents prevent changes in the magnetic field within the toroidal pick-up loop and produce a current signal independent of the beam's cross-section and its position within the toroid, while the combination of superconducting elements provides current measurement sensitivities in the nano-ampere range.

  19. Beam current sensor

    DOEpatents

    Kuchnir, Moyses; Mills, Frederick E.

    1987-01-01

    A current sensor for measuring the DC component of a beam of charged particles employs a superconducting pick-up loop probe, with twisted superconducting leads in combination with a Superconducting Quantum Interference Device (SQUID) detector. The pick-up probe is in the form of a single-turn loop, or a cylindrical toroid, through which the beam is directed and within which a first magnetic flux is excluded by the Meisner effect. The SQUID detector acts as a flux-to-voltage converter in providing a current to the pick-up loop so as to establish a second magnetic flux within the electrode which nulls out the first magnetic flux. A feedback voltage within the SQUID detector represents the beam current of the particles which transit the pick-up loop. Meisner effect currents prevent changes in the magnetic field within the toroidal pick-up loop and produce a current signal independent of the beam's cross-section and its position within the toroid, while the combination of superconducting elements provides current measurement sensitivites in the nano-ampere range.

  20. Beam dynamics group summary

    SciTech Connect

    Peggs, S.

    1994-12-31

    This paper summarizes the activities of the beam dynamics working group of the LHC Collective Effects Workshop that was held in Montreux in 1994. It reviews the presentations that were made to the group, the discussions that ensued, and the consensuses that evolved.

  1. Fabricating Structural Beams

    NASA Technical Reports Server (NTRS)

    Engler, E. E.; Ehl, J.; Muench, W.; Morfin, H.; Huber, J.; Braun, R.; Marx, W.; Alberi, A.; Romaneck, R.; Johnson, C.; Giannuzzi, O.; Weyhreter, A.

    1982-01-01

    Automatic machine described in new report has demonstrated on Earth feasibility of machine fabricating beams for huge structures in space. Such structures include solar mirrors, radiometer reflectors, microwave power transmitters, solar-thermal power generators, and solar photoelectric generators, ranging in size from few hundred meters long to tens of kilometers long.

  2. Recycled Paper Beam Sculpture

    ERIC Educational Resources Information Center

    Keller, Kristin; Tabacchi, Jo

    2011-01-01

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

  3. Pulsed ion beam source

    DOEpatents

    Greenly, J.B.

    1997-08-12

    An improved pulsed ion beam source is disclosed having a new biasing circuit for the fast magnetic field. This circuit provides for an initial negative bias for the field created by the fast coils in the ion beam source which pre-ionize the gas in the source, ionize the gas and deliver the gas to the proper position in the accelerating gap between the anode and cathode assemblies in the ion beam source. The initial negative bias improves the interaction between the location of the nulls in the composite magnetic field in the ion beam source and the position of the gas for pre-ionization and ionization into the plasma as well as final positioning of the plasma in the accelerating gap. Improvements to the construction of the flux excluders in the anode assembly are also accomplished by fabricating them as layered structures with a high melting point, low conductivity material on the outsides with a high conductivity material in the center. 12 figs.

  4. Ion-beam technologies

    SciTech Connect

    Fenske, G.R.

    1993-01-01

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

  5. Bonding aluminum beam leads

    NASA Technical Reports Server (NTRS)

    Burkett, F. S.

    1978-01-01

    Report makes it relatively easy for hybrid-circuit manufacturers to convert integrated circuit chips with aluminum bead leads. Report covers: techniques for handling tiny chips; proper geometries for ultrasonic bonding tips; best combinations of pressure, pulse time, and ultrasonic energy for bonding; and best thickness for metal films to which beam leads are bonded.

  6. Neutral particle beam intensity controller

    DOEpatents

    Dagenhart, William K.

    1986-01-01

    A neutral beam intensity controller is provided for a neutral beam generator in which a neutral beam is established by accelerating ions from an ion source into a gas neutralizer. An amplitude modulated, rotating magnetic field is applied to the accelerated ion beam in the gas neutralizer to defocus the resultant neutral beam in a controlled manner to achieve intensity control of the neutral beam along the beam axis at constant beam energy. The rotating magnetic field alters the orbits of ions in the gas neutralizer before they are neutralized, thereby controlling the fraction of neutral particles transmitted out of the neutralizer along the central beam axis to a fusion device or the like. The altered path or defocused neutral particles are sprayed onto an actively cooled beam dump disposed perpendicular to the neutral beam axis and having a central open for passage of the focused beam at the central axis of the beamline. Virtually zero therough 100% intensity control is achieved by varying the magnetic field strength without altering the ion source beam intensity or its species yield.

  7. Noncoaxial Bessel-Gauss beams.

    PubMed

    Huang, Chaohong; Zheng, Yishu; Li, Hanqing

    2016-04-01

    We proposed a new family of noncoaxial Gauss-truncated Bessel beams through multiplying conventional symmetrical Bessel beams by a noncoaxial Gauss function. These beams can also be regarded as the exponential-truncated version of Bessel-Gauss beams since they can be transformed into the product of Bessel-Gauss beams and an exponential window function along a certain Cartesian axis. The closed-form solutions of the angular spectra and paraxial propagation of these beams were derived. These beams have asymmetrical intensity distributions and carry the same orbit angular momentum per photon as the corresponding Bessel-Gauss beams. While propagating along the z axis, the mth (m≠0) noncoaxial Bessel-Gauss beams rotate their intensity distributions and the mth-order vortex at the beam center has a transverse shift along the direction perpendicular to the offset axis. Depending on the product of the transverse scalar factor of the Bessel beams and the offset between the Gaussian window function and the center of the Bessel beams, the noncoaxial Bessel-Gauss beams can produce unit vortices with opposite signs in pairs during propagation.

  8. Intense Pulsed Heavy Ion Beam Technology

    NASA Astrophysics Data System (ADS)

    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.

  9. Beam-Beam Diagnostics from Closed-Orbit Distortion

    SciTech Connect

    Furman, M.; Chin, Y.-H.; Eden, J.; Kozanecki, W.; Tennyson, J.; Ziemann, V.

    1992-07-01

    The authors study the applicability of beam-beam deflection techniques as a tuning tool for asymmetric B factories, focusing on PEP-II as an example. Assuming that the closed orbits of the two beams are separated vertically at the interaction point by a local orbit bump that is nominally closed, they calculate the residual beam orbit distortions due to the beam-beam interaction. Difference orbit measurements, performed at points conveniently distant from the interaction point (IP), provide distinct signatures that can be used to maintain the beams in collision and perform detailed optical diagnostics at the IP. A proposal to test this method experimentally at the TRISTAN ring is briefly discussed. Because of their two-ring structure, asymmetric B factories are likely to require more diagnostics and feedback mechanisms than single-ring colliders in order to guarantee head-on collisions. In addition to the traditional techniques, however, the independence of the two beams allows one to envisage other kinds of beam diagnostics. In this article they investigate one such possibility, by looking at the closed orbit distortion produced by the beam-beam interaction when the beams do not collide exactly head-on. They base this investigation on an analytic model and strong-strong multiparticle simulations. Although the discussion uses the PEP-II design as an example, the conclusion is that this technique is quite a promising diagnostics tool for asymmetric colliders in general.

  10. Beam experiments towards high-intensity beams in RHIC

    SciTech Connect

    Montag C.; Ahrens, L.; Brennan, J.M.; Blaskiewicz, M.; Drees, A.; Fischer, W.; Hayes, T.; Huang, H.; Mernick, K.; Robert-Demolaize, G.; Smith, K.; Than, R.; Thieberger, P.; Yip, K.; Zeno, K.; Zhang, S.Y.

    2012-05-20

    Proton bunch intensities in RHIC are planned to be increased from 2 {center_dot} 10{sup 11} to 3 {center_dot} 10{sup 11} protons per bunch to increase the luminosity, together with head-on beam-beam compensation using electron lenses. To study the feasibility of the intensity increase, beam experiments are being performed. Recent experimental results are presented.

  11. Decoherence of beam oscillations in the SSC due to beam-beam collisions

    SciTech Connect

    Tsyganov, E.; Shih, H.J.; Meinke, R.; Nexsen, W.; Banda-Herath, M. ); Taratin, A. )

    1994-10-01

    Computer simulations were made to study the decoherence of beam oscillations in the SSC collider due to the tune shift generated by the head-on beam-beam interaction. The simulation results on the average tune shift and the rums tune spread were compared with previous theoretical estimates and excellent agreement was found. The simulations also confirmed the expectation that the decoherence time increases with decreasing tune spread in the beam. A simple procedure was presented to quantify the decoherence time from the simulated growth of the beam emittance relative to the beam centroid.

  12. Laser beam pulse formatting method

    DOEpatents

    Daly, Thomas P.; Moses, Edward I.; Patterson, Ralph W.; Sawicki, Richard H.

    1994-01-01

    A method for formatting a laser beam pulse (20) using one or more delay loops (10). The delay loops (10) have a partially reflective beam splitter (12) and a plurality of highly reflective mirrors (14) arranged such that the laser beam pulse (20) enters into the delay loop (10) through the beam splitter (12) and circulates therein along a delay loop length (24) defined by the mirrors (14). As the laser beam pulse (20) circulates within the delay loop (10) a portion thereof is emitted upon each completed circuit when the laser beam pulse (20) strikes the beam splitter (12). The laser beam pulse (20) is thereby formatted into a plurality of sub-pulses (50, 52, 54 and 56). The delay loops (10) are used in combination to produce complex waveforms by combining the sub-pulses (50, 52, 54 and 56) using additive waveform synthesis.

  13. Beam Rounders for Circular Colliders

    SciTech Connect

    A. Burov; S. Nagaitsev; Ya. Derbenev

    2001-07-01

    By means of linear optics, an arbitrary uncoupled beam can be locally transformed into a round (rotation-invariant) state and then back. This provides an efficient way to round beams in the interaction region of circular colliders.

  14. Beam rounders for circular colliders

    SciTech Connect

    A. Burov and S. Nagaitsev

    2002-12-10

    By means of linear optics, an arbitrary uncoupled beam can be locally transformed into a round (rotation-invariant) state and then back. This provides an efficient way to round beams in the interaction region of circular colliders.

  15. Consistently Showing Your Best Side? Intra-individual Consistency in #Selfie Pose Orientation

    PubMed Central

    Lindell, Annukka K.

    2017-01-01

    Painted and photographic portraits of others show an asymmetric bias: people favor their left cheek. Both experimental and database studies confirm that the left cheek bias extends to selfies. To date all such selfie studies have been cross-sectional; whether individual selfie-takers tend to consistently favor the same pose orientation, or switch between multiple poses, remains to be determined. The present study thus examined intra-individual consistency in selfie pose orientations. Two hundred selfie-taking participants (100 male and 100 female) were identified by searching #selfie on Instagram. The most recent 10 single-subject selfies for the each of the participants were selected and coded for type of selfie (normal; mirror) and pose orientation (left, midline, right), resulting in a sample of 2000 selfies. Results indicated that selfie-takers do tend to consistently adopt a preferred pose orientation (α = 0.72), with more participants showing an overall left cheek bias (41%) than would be expected by chance (overall right cheek bias = 31.5%; overall midline bias = 19.5%; no overall bias = 8%). Logistic regression modellng, controlling for the repeated measure of participant identity, indicated that sex did not affect pose orientation. However, selfie type proved a significant predictor when comparing left and right cheek poses, with a stronger left cheek bias for mirror than normal selfies. Overall, these novel findings indicate that selfie-takers show intra-individual consistency in pose orientation, and in addition, replicate the previously reported left cheek bias for selfies and other types of portrait, confirming that the left cheek bias also presents within individuals’ selfie corpora. PMID:28270790

  16. Ion-beam machining of millimeter scale optics.

    PubMed

    Shanbhag, P M; Feinberg, M R; Sandri, G; Horenstein, M N; Bifano, T G

    2000-02-01

    An ion-beam microcontouring process is developed and implemented for figuring millimeter scale optics. Ion figuring is a noncontact machining technique in which a beam of high-energy ions is directed toward a target substrate to remove material in a predetermined and controlled fashion. Owing to this noncontact mode of material removal, problems associated with tool wear and edge effects, which are common in conventional machining processes, are avoided. Ion-beam figuring is presented as an alternative for the final figuring of small (<1-mm) optical components. The depth of the material removed by an ion beam is a convolution between the ion-beam shape and an ion-beam dwell function, defined over a two-dimensional area of interest. Therefore determination of the beam dwell function from a desired material removal map and a known steady beam shape is a deconvolution process. A wavelet-based algorithm has been developed to model the deconvolution process in which the desired removal contours and ion-beam shapes are synthesized numerically as wavelet expansions. We then mathematically combined these expansions to compute the dwell function or the tool path for controlling the figuring process. Various models have been developed to test the stability of the algorithm and to understand the critical parameters of the figuring process. The figuring system primarily consists of a duo-plasmatron ion source that ionizes argon to generate a focused (approximately 200-microm FWHM) ion beam. This beam is rastered over the removal surface with a perpendicular set of electrostatic plates controlled by a computer guidance system. Experimental confirmation of ion figuring is demonstrated by machining a one-dimensional sinusoidal depth profile in a prepolished silicon substrate. This profile was figured to within a rms error of 25 nm in one iteration.

  17. Holographic memory using beam steering

    NASA Technical Reports Server (NTRS)

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

    2006-01-01

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

  18. Beam Dump Design for the Rare Isotope Accelerator Fragmentation Line

    SciTech Connect

    Stein, W; Ahle, L E; Reyes, S

    2006-05-02

    Beam dumps for the heavy ion beams of the fragmentation line of the Rare Isotope Accelerator have been designed. The most severe operational case involves a continuous U beam impacting the beam dump with a power of 295 kW and a nominal spot diameter size of 5 cm. The dump mechanically consists of two rotating barrels with a water cooled outer wall of 2 mm thick aluminum. The barrels are 70 cm in diameter and axially long enough to intercept a variety of other beams. The aluminum wall absorbs approximately 15% of the U beam power with the rest absorbed in the water downstream of the wall. The water acts as an absorber of the beam and as a coolant for the 2 mm aluminum wall. The barrel rotates at less than 400 RPM, maximum aluminum temperatures are less than 100 C and maximum thermal fatigue stresses are low at 3.5 x 10{sup 7} Pa (5 ksi). Rotation of the dump results in relatively low radiation damage levels with an operating lifetime of years for most beams.

  19. Experimental investigation of fatigue in a cantilever energy harvesting beam

    NASA Astrophysics Data System (ADS)

    Avvari, Panduranga Vittal; Yang, Yaowen; Liu, Peiwen; Soh, Chee Kiong

    2015-03-01

    Over the last decade, cantilever energy harvesters gained immense popularity owing to the simplicity of the design and piezoelectric energy harvesting (PEH) using the cantilever design has undergone considerable evolution. The major drawback of a vibrating cantilever beam is its vulnerability to fatigue over a period of time. This article brings forth an experimental investigation into the phenomenon of fatigue of a PEH cantilever beam. As there has been very little literature reported in this area, an effort has been made to scrutinize the damage due to fatigue in a linear vibrating cantilever PEH beam consisting of an aluminum substrate with a piezoelectric macro-fiber composite (MFC) patch attached near the root of the beam and a tip mass attached to the beam. The beam was subjected to transverse vibrations and the behavior of the open circuit voltage was recorded with passing time. Moreover, electro-mechanical admittance readings were obtained periodically using the same MFC patch as a Structural health monitoring (SHM) sensor to assess the health of the PEH beam. The results show that with passing time the PEH beam underwent fatigue in both the substrate and MFC, which is observed in a complimentary trend in the voltage and admittance readings. The claim is further supported using the variation of root mean square deviation (RMSD) of the real part of admittance (conductance) readings. Thus, this study concludes that the fatigue issue should be addressed in the design of PEH for long term vibration energy harvesting.

  20. Nonlinear analysis of a relativistic beam-plasma cyclotron instability

    NASA Technical Reports Server (NTRS)

    Sprangle, P.; Vlahos, L.

    1986-01-01

    A self-consistent set of nonlinear and relativistic wave-particle equations are derived for a magnetized beam-plasma system interacting with electromagnetic cyclotron waves. In particular, the high-frequency cyclotron mode interacting with a streaming and gyrating electron beam within a background plasma is considered in some detail. This interaction mode may possibly find application as a high-power source of coherent short-wavelength radiation for laboratory devices. The background plasma, although passive, plays a central role in this mechanism by modifying the dielectric properties in which the magnetized electron beam propagates. For a particular choice of the transverse beam velocity (i.e., the speed of light divided by the relativistic mass factor), the interaction frequency equals the nonrelativistic electron cyclotron frequency times the relativistic mass factor. For this choice of transverse beam velocity the detrimental effects of a longitudinal beam velocity spread is virtually removed. Power conversion efficiencies in excess of 18 percent are both analytically calculated and obtained through numerical simulations of the wave-particle equations. The quality of the electron beam, degree of energy and pitch angle spread, and its effect on the beam-plasma cyclotron instability is studied.

  1. Freeform beam shaping for high-power multimode lasers

    NASA Astrophysics Data System (ADS)

    Laskin, Alexander; Laskin, Vadim

    2014-03-01

    Widening of using high power multimode lasers in industrial laser material processing is accompanied by special requirements to irradiance profiles in such technologies like metal or plastics welding, cladding, hardening, brazing, annealing, laser pumping and amplification in MOPA lasers. Typical irradiance distribution of high power multimode lasers: free space solid state, fiber-coupled solid state and diodes lasers, fiber lasers, is similar to Gaussian. Laser technologies can be essentially improved when irradiance distribution on a workpiece is uniform (flattop) or inverse-Gauss; when building high-power pulsed lasers it is possible to enhance efficiency of pumping and amplification by applying super-Gauss irradiance distribution with controlled convexity. Therefore, "freeform" beam shaping of multimode laser beams is an important task. A proved solution is refractive field mapping beam shaper like Shaper capable to control resulting irradiance profile - with the same unit it is possible to get various beam profiles and choose optimum one for a particular application. Operational principle of these devices implies transformation of laser irradiance distribution by conserving beam consistency, high transmittance, providing collimated low divergent output beam. Using additional optics makes it possible to create resulting laser spots of necessary size and round, elliptical or linear shape. Operation out of focal plane and, hence, in field of lower wavefront curvature, allows extending depth of field. The refractive beam shapers are implemented as telescopes and collimating systems, which can be connected directly to fiber-coupled lasers or fiber lasers, thus combining functions of beam collimation and irradiance transformation.

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

    SciTech Connect

    Kurennoy, S.

    2002-01-01

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

  3. Dual-beam laser traps in biology and medicine: when one beam is not enough

    NASA Astrophysics Data System (ADS)

    Whyte, Graeme; Lautenschläger, Franziska; Kreysing, Moritz; Boyde, Lars; Ekpenyong, Andrew; Delabre, Ulysse; Chalut, Kevin; Franze, Kristian; Guck, Jochen

    2010-08-01

    Optical traps are nowadays quite ubiquitous in biophysical and biological studies. The term is often used synonymously with optical tweezers, one particular incarnation of optical traps. However, there is another kind of optical trap consisting of two non-focused, counter-propagating laser beams. This dual-beam trap predates optical tweezers by almost two decades and currently experiences a renaissance. The advantages of dual-beam traps include lower intensities on the trapped object, decoupling from imaging optics, and the possibility to trap cells and cell clusters up to 100 microns in diameter. When used for deforming cells this trap is referred to as an optical stretcher. I will review several applications of such traps in biology and medicine for the detection of cancer cells, sorting stem cells, testing light guiding properties of retinal cells and the controlled rotation of cells for single cell tomography.

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

    SciTech Connect

    Stupakov, G.

    1991-11-01

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

  5. Cherenkov Light-based Beam Profiling for Ultrarelativistic Electron Beams

    SciTech Connect

    Adli, E.; Gessner, S. J.; Corde, S.; Hogan, M. J.; Bjerke, H. H.

    2015-02-09

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

  6. Kiloamp high-brightness beams

    SciTech Connect

    Caporaso, G.J.

    1987-01-01

    Brightness preservation of high-current relativistic electron beams under two different types of transport is discussed. Recent progress in improving the brightness of laser-guided beams in the Advanced Test Accelerator is reviewed. A strategy for the preservation of the brightness of space-charge-dominated beams in a solenoidal transport system is presented.

  7. Depressed collector for electron beams

    NASA Technical Reports Server (NTRS)

    Ives, R. Lawrence (Inventor)

    2005-01-01

    A depressed collector for recovery of spent beam energy from electromagnetic sources emitting sheet or large aspect ration annular electron beams operating aver a broad range of beam voltages and currents. The collector incorporates a trap for capturing and preventing the return of reflected and secondary electrons.

  8. Characterization of colloid thruster beams

    NASA Technical Reports Server (NTRS)

    Gamero-Castano, M.; Ziemer, J.

    2005-01-01

    In this article we use retarding potential, time of flight, and a Faraday cup, to measure the energy and specific charge distributions of the electrospray particles as a function of the position within the beam, as well as beam profiles. This information is then used, together with a model of the beam, to calculate its spreading.

  9. SLC polarized beam source electron optics design

    SciTech Connect

    Eppley, K.R.; Lavine, T.L.; Early, R.A.; Herrmannsfeldt, W.B.; Miller, R.H.; Schultz, D.C.; Spencer, C.M.; Yeremian, A.D.

    1991-05-01

    This paper describes the design of the beam-line from the polarized electron gun to the linac injector in the Stanford Linear Collider (SLC). The polarized electron source is a GaAs photocathode, requiring 10{sup {minus}11}-Torr-range pressure for adequate quantum efficiency and longevity. The photocathode is illuminated by 3-nsec-long laser pulses. The quality of the optics for the 160-kV beam is crucial since electron-stimulated gas desorption from beam loss in excess of 0.1% of the 20-nC pulses may poison the photocathode. Our design for the transport line consists of a differential pumping region isolated by a pair of valves. Focusing is provided by a pair of Helmholtz coils and by several iron-encased solenoidal lenses. Our optics design is based on beam transport simulations using 2{1/2}-D particle-in-cell codes to model the gun and to solve the fully-relativistic time-dependent equations of motion in three dimensions for electrons in the presence of azimuthally symmetric electromagnetic fields. 6 refs., 6 figs.

  10. Modeling FAMA ion beam diagnostics based on the Ptolemy II model

    NASA Astrophysics Data System (ADS)

    Balvanović, R.; Beličev, P.; Radjenović, B.

    2012-10-01

    The previously developed model of ion beam transport control of the FAMA facility is further enhanced by equipping it with the model of ion beam diagnostics. The model of control, executing once, is adjusted so that it executes in iterative mode, where each iteration samples the input beam normally distributed over initial phase space and calculates a single trajectory through the facility beam lines. The model takes into account only the particles that manage to pass through all the beam line apertures, emulating in this way a Faraday cup and a beam profile meter. Generated are also beam phase space distributions and horizontal and vertical beam profiles at the end of the beam transport lines the FAMA facility consists of. By adding the model of ion beam diagnostics to the model of ion beam transport control, the process of determining optimal ion beam control parameters is eased and speeded up, and the understanding of influence of control parameters on the ion beam characteristics is improved.

  11. SU-E-T-145: Beam Characteristics of Flattening Filter Free Beams Including Low Dose Rate Setting

    SciTech Connect

    Uehara, K; Ogata, T; Nakayama, M; Shinji, T; Nishimura, H; Masutani, T; Ishihara, T; Ejima, Y; Sasaki, R

    2015-06-15

    Purpose: In commissioning of volumetric modulated arc therapy (VMAT), it is necessary to evaluate the beam characteristics of various dose rate settings with potential to use. The aim of this study is to evaluate the beam characteristics of flattened and flattening filter free (FFF) including low dose rate setting. Methods: We used a Varian TrueBeam with Millennium 120 MLC. Both 6 and 10 MV beams with or without flattening filter were used for this study. To evaluate low-dose rate FFF beams, specially-designed leaf sequence files control out-of-field MLC leaf pair at constant dose rate ranging from 80 to 400 MU/min. For dose rate from 80 MU/min to the maximum usable value of all energies, beam output were measured using ionization chamber (CC04, IBA). The ionization chamber was inserted into water equivalent phantom (RT3000-New, R-tech), and the phantom was set with SAD of 100cm. The beam profiles were performed using the 2D diode array (Profiler2, Sun Nuclear). The SSD was set to 90cm and a combined 30cmx30cmx9cm phantom which consisted of solid water slabs was put on the device. All measurement were made using 100MU irradiation for 10cmx10cm jaw-defined field size with a gantry angle of 0°. Results: In all energies, the dose rate dependences with beam output and variation coefficient were within 0.2% and 0.07%, respectively. The flatness and symmetry exhibited small variations (flatness ≤0.1 point and symmetry≤0.3 point at absolute difference). Conclusion: We had studied the characteristics of flattened and FFF beam over the 80 MU/min. Our results indicated that the beam output and profiles of FFF of TrueBeam linac were highly stable at low dose rate setting.

  12. Definition of Beam Diameter for Electron Beam Welding

    SciTech Connect

    Burgardt, Paul; Pierce, Stanley W.; Dvornak, Matthew John

    2016-03-11

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

  13. Closed orbit distortion and the beam-beam interaction

    SciTech Connect

    Furman, M.; Chin, Y.H.; Eden, J.; Kozanecki, W. |; Tennyson, J.; Ziemann, V.

    1992-06-01

    We study the applicability of beam-beam deflection techniques as a tuning tool for the SLAC/LBL/LLNL B factory, PEP-II. Assuming that the closed orbits of the two beams are separated vertically at the interaction point by a local orbit bump that is nominally closed, we calculate the residual beam orbit distortions due to the beam-beam interaction. Difference orbit measurements, performed at points conveniently distant from the IP, provide distinct coordinate- or frequency-space signatures that can be used to maintain the beams in collision and perform detailed optical diagnostics at the IP. A proposal to test this method experimentally at the TRISTAN ring is briefly discussed.

  14. Closed Orbit Distortion and the Beam-Beam Interaction

    SciTech Connect

    Furman, M.; Chin, Y.; Eden, J.; Kozanecki, W.; Tennyson, J.L.; Ziemann, V.; /SLAC

    2007-02-23

    We study the applicability of beam-beam deflection techniques as a tuning tool for the SLAC/LBL/LLNL B factory, PEP-II. Assuming that the closed orbits of the two beams are separated vertically at the interaction point by a local orbit bump that is nominally closed, we calculate the residual beam orbit distortions due to the beam-beam interaction. Difference orbit measurements, performed at points conveniently distant from the IP, provide distinct coordinate- or frequency-space signatures that can be used to maintain the beams in collision and perform detailed optical diagnostics at the IP. A proposal to test this method experimentally at the TRISTAN ring is briefly discussed.

  15. Metallic beam development for the Facility for Rare Isotope Beam

    SciTech Connect

    Machicoane, Guillaume Cole, Dallas; Leitner, Daniela; Neben, Derek; Tobos, Larry

    2014-02-15

    The Facility for Rare Isotope Beams (FRIB) at Michigan State University (MSU) will accelerate a primary ion beam to energies beyond 200 MeV/u using a superconducting RF linac and will reach a maximum beam power of 400 kW on the fragmentation target. The beam intensity needed from the ECR ion source is expected to be between 0.4 and 0.5 emA for most medium mass to heavy mass elements. Adding to the challenge of reaching the required intensity, an expanded list of primary beams of interest has been established based on the production rate and the number of isotope beams that could be produced with FRIB. We report here on the development done for some of the beam in the list including mercury (natural), molybdenum ({sup 98}Mo), and selenium ({sup 82}Ser)

  16. Recent advances of strong-strong beam-beam simulation

    SciTech Connect

    Qiang, Ji; Furman, Miguel A.; Ryne, Robert D.; Fischer, Wolfram; Ohmi,Kazuhito

    2004-09-15

    In this paper, we report on recent advances in strong-strong beam-beam simulation. Numerical methods used in the calculation of the beam-beam forces are reviewed. A new computational method to solve the Poisson equation on nonuniform grid is presented. This method reduces the computational cost by a half compared with the standard FFT based method on uniform grid. It is also more accurate than the standard method for a colliding beam with low transverse aspect ratio. In applications, we present the study of coherent modes with multi-bunch, multi-collision beam-beam interactions at RHIC. We also present the strong-strong simulation of the luminosity evolution at KEKB with and without finite crossing angle.

  17. Using a short-pulse diffraction-limited laser beam to probe filamentation of a random phase plate smoothed beam.

    PubMed

    Kline, J L; Montgomery, D S; Flippo, K A; Johnson, R P; Rose, H A; Shimada, T; Williams, E A

    2008-10-01

    A short pulse (few picoseconds) laser probe provides high temporal resolution measurements to elucidate details of fast dynamic phenomena not observable with typical longer laser pulse probes and gated diagnostics. Such a short pulse laser probe (SPLP) has been used to measure filamentation of a random phase plate (RPP) smoothed laser beam in a gas-jet plasma. The plasma index of refraction due to driven density and temperature fluctuations by the RPP beam perturbs the phase front of a SPLP propagating at a 90 degree angle with respect to the RPP interaction beam. The density and temperature fluctuations are quasistatic on the time scale of the SPLP (approximately 2 ps). The transmitted near-field intensity distribution from the SPLP provides a measure of the phase front perturbation. At low plasma densities, the transmitted intensity pattern is asymmetric with striations across the entire probe beam in the direction of the RPP smoothed beam. As the plasma density increases, the striations break up into smaller sizes along the direction of the RPP beam propagation. The breakup of the intensity pattern is consistent with self-focusing of the RPP smoothed interaction beam. Simulations of the experiment using the wave propagation code, PF3D, are in qualitative agreement demonstrating that the asymmetric striations can be attributed to the RPP driven density fluctuations. Quantification of the beam breakup measured by the transmitted SPLP could lead to a new method for measuring self-focusing of lasers in underdense plasmas.

  18. White beam slits and pink beam slits for the hard x-ray nanoprobe beamline at the Advanced Photon Source.

    SciTech Connect

    Benson, C.; Jaski, Y.; Maser, J.; Powers, T.; Schmidt, O.; Rossi, E.

    2007-01-01

    A new type of slit has been designed for use in the hard x-ray nanoprobe beamline at the Advanced Photon Source (APS). The design incorporates monolithic GlidCop slit bodies mounted to commercially available x-y drive systems. Long, tapered apertures with adjacent water-cooling channels intercept the x-ray beam, removing the high heat load produced by two collinear APS undulators. The apertures are L-shaped and provide both horizontal and vertical slits. The beam-defining edges, positioned at the end of the tapered surfaces, consist of two sets of tungsten blades. These blades produce an exit beam with sharp corners and assure a clean cut-off for the white beam edges. The slit assembly is designed to allow overlap of the slit edges to stop the beam. The white beam slit design accommodates 3100 W of total power with a peak power density of 763 W/mm2. The pink beam slit design accommodates 400 W of total power with a peak power density of 180 W/mm2. Detailed thermal analyses were performed to verify the slits accuracy under full beam loading. The new concept allows beamline operations to 180 mA with a simplified design approach.

  19. White Beam Slits and Pink Beam Slits for the Hard X-ray Nanoprobe Beamline at the Advanced Photon Source

    SciTech Connect

    Benson, C.; Jaski, Y.; Powers, T.; Schmidt, O.; Rossi, E.; Maser, J.

    2007-01-19

    A new type of slit has been designed for use in the hard x-ray nanoprobe beamline at the Advanced Photon Source (APS). The design incorporates monolithic GlidCop slit bodies mounted to commercially available x-y drive systems. Long, tapered apertures with adjacent water-cooling channels intercept the x-ray beam, removing the high heat load produced by two collinear APS undulators. The apertures are L-shaped and provide both horizontal and vertical slits. The beam-defining edges, positioned at the end of the tapered surfaces, consist of two sets of tungsten blades. These blades produce an exit beam with sharp corners and assure a clean cut-off for the white beam edges. The slit assembly is designed to allow overlap of the slit edges to stop the beam.The white beam slit design accommodates 3100 W of total power with a peak power density of 763 W/mm2. The pink beam slit design accommodates 400 W of total power with a peak power density of 180 W/mm2. Detailed thermal analyses were performed to verify the slits' accuracy under full beam loading. The new concept allows beamline operations to 180 mA with a simplified design approach.

  20. Beam delivery system with a non-digitized diffractive beam splitter for laser-drilling of silicon

    NASA Astrophysics Data System (ADS)

    Amako, J.; Fujii, E.

    2016-02-01

    We report a beam-delivery system consisting of a non-digitized diffractive beam splitter and a Fourier transform lens. The system is applied to the deep-drilling of silicon using a nanosecond pulse laser in the manufacture of inkjet printer heads. In this process, a circularly polarized pulse beam is divided into an array of uniform beams, which are then delivered precisely to the process points. To meet these requirements, the splitter was designed to be polarization-independent with an efficiency>95%. The optical elements were assembled so as to allow the fine tuning of the effective overall focal length by adjusting the wavefront curvature of the beam. Using the system, a beam alignment accuracy of<5 μm was achieved for a 12-mm-wide beam array and the throughput was substantially improved (10,000 points on a silicon wafer drilled in ~1 min). This beam-delivery scheme works for a variety of laser applications that require parallel processing.

  1. Beam-centric algorithm for pretreatment patient position correction in external beam radiation therapy

    SciTech Connect

    Bose, Supratik; Shukla, Himanshu; Maltz, Jonathan

    2010-05-15

    Purpose: In current image guided pretreatment patient position adjustment methods, image registration is used to determine alignment parameters. Since most positioning hardware lacks the full six degrees of freedom (DOF), accuracy is compromised. The authors show that such compromises are often unnecessary when one models the planned treatment beams as part of the adjustment calculation process. The authors present a flexible algorithm for determining optimal realizable adjustments for both step-and-shoot and arc delivery methods. Methods: The beam shape model is based on the polygonal intersection of each beam segment with the plane in pretreatment image volume that passes through machine isocenter perpendicular to the central axis of the beam. Under a virtual six-DOF correction, ideal positions of these polygon vertices are computed. The proposed method determines the couch, gantry, and collimator adjustments that minimize the total mismatch of all vertices over all segments with respect to their ideal positions. Using this geometric error metric as a function of the number of available DOF, the user may select the most desirable correction regime. Results: For a simulated treatment plan consisting of three equally weighted coplanar fixed beams, the authors achieve a 7% residual geometric error (with respect to the ideal correction, considered 0% error) by applying gantry rotation as well as translation and isocentric rotation of the couch. For a clinical head-and-neck intensity modulated radiotherapy plan with seven beams and five segments per beam, the corresponding error is 6%. Correction involving only couch translation (typical clinical practice) leads to a much larger 18% mismatch. Clinically significant consequences of more accurate adjustment are apparent in the dose volume histograms of target and critical structures. Conclusions: The algorithm achieves improvements in delivery accuracy using standard delivery hardware without significantly increasing

  2. Self-consistent particle-in-cell simulations of fundamental and harmonic radio plasma emission mechanisms

    NASA Astrophysics Data System (ADS)

    Tsiklauri, D.; Thurgood, J. O.

    2015-12-01

    first co-author Jonathan O. Thurgood (QMUL) The simulation of three-wave interaction based plasma emission, an underlying mechanism for type III solar radio bursts, is a challenging task requiring fully-kinetic, multi-dimensional models. This paper aims to resolve a contradiction in past attempts, whereby some authors report that no such processes occur and others draw conflicting conclusions, by using 2D, fully kinetic, particle-in-cell simulations of relaxing electron beams. Here we present the results of particle-in-cell simulations which for different physical parameters permit or prohibit the plasma emission. We show that the possibility of plasma emission is contingent upon the frequency of the initial electrostatic waves generated by the bump-in-tail instability, and that these waves may be prohibited from participating in the necessary three-wave interactions due to the frequency beat requirements. We caution against simulating astrophysical radio bursts using unrealistically dense beams (a common approach which reduces run time), as the resulting non-Langmuir characteristics of the initial wave modes significantly suppresses the emission. Comparison of our results indicates that, contrary to the suggestions of previous authors, a plasma emission mechanism based on two counter-propagating beams is unnecessary in astrophysical context. Finally, we also consider the action of the Weibel instability, which generates an electromagnetic beam mode. As this provides a stronger contribution to electromagnetic energy than the emission, we stress that evidence of plasma emission in simulations must disentangle the two contributions and not simply interpret changes in total electromagnetic energy as the evidence of plasma emission. In summary, we present the first self-consistent demonstration of fundamental and harmonic plasma emission from a single-beam system via fully kinetic numerical simulation. Pre-print can be found at http://astro.qmul.ac.uk/~tsiklauri/jtdt1

  3. LEDA beam diagnostics instrumentation: Beam current measurement

    NASA Astrophysics Data System (ADS)

    Barr, D.; Day, L.; Gilpatrick, J. D.; Kasemir, K.-U.; Martinez, D.; Power, J. F.; Shurter, R.; Stettler, M.

    2000-11-01

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

  4. CLASHING BEAM PARTICLE ACCELERATOR

    DOEpatents

    Burleigh, R.J.

    1961-04-11

    A charged-particle accelerator of the proton synchrotron class having means for simultaneously accelerating two separate contra-rotating particle beams within a single annular magnet structure is reported. The magnet provides two concentric circular field regions of opposite magnetic polarity with one field region being of slightly less diameter than the other. The accelerator includes a deflector means straddling the two particle orbits and acting to collide the two particle beams after each has been accelerated to a desired energy. The deflector has the further property of returning particles which do not undergo collision to the regular orbits whereby the particles recirculate with the possibility of colliding upon subsequent passages through the deflector.

  5. Laser beam guard clamps

    SciTech Connect

    Dickson, Richard K.

    2010-09-07

    A quick insert and release laser beam guard panel clamping apparatus having a base plate mountable on an optical table, a first jaw affixed to the base plate, and a spring-loaded second jaw slidably carried by the base plate to exert a clamping force. The first and second jaws each having a face acutely angled relative to the other face to form a V-shaped, open channel mouth, which enables wedge-action jaw separation by and subsequent clamping of a laser beam guard panel inserted through the open channel mouth. Preferably, the clamping apparatus also includes a support structure having an open slot aperture which is positioned over and parallel with the open channel mouth.

  6. Oberst beam test technique

    NASA Astrophysics Data System (ADS)

    Fasana, Alessandro; Garibaldi, Luigi; Giorcelli, Ermanno; Ruzzene, Massimo

    1998-06-01

    The definition of the mechanical properties of viscoelastic materials, i.e. the elastic modulus and the loss factor, is carried out, according to many national and international standards, with many different techniques, both of the resonant and non-resonant type. In this paper we focus our attention on the pros and cons of the resonant technique based on the classical Oberst beam method. When the damping material to be tested is not self-supporting, its properties are determined taking start from the measured modal frequencies and loss factors of a laminated beam, constituted by one or two metallic strips, ideally undamped, and one or two viscoelastic layers. The formulae specified on the standards hold valid under the assumptions of the theory developed by Kerwin, Ungar and Ross and we try in this paper to quantify witch deviation of the results should be expected when moving away from their ideal hypotheses.

  7. Laser beam steering device

    NASA Technical Reports Server (NTRS)

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

    1993-01-01

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

  8. Refinement of Timoshenko Beam Theory for Composite and Sandwich Beams Using Zigzag Kinematics

    NASA Technical Reports Server (NTRS)

    Tessler, Alexander; DiSciuva, Marco; Gherlone, Marco

    2007-01-01

    A new refined theory for laminated-composite and sandwich beams that contains the kinematics of the Timoshenko Beam Theory as a proper baseline subset is presented. This variationally consistent theory is derived from the virtual work principle and employs a novel piecewise linear zigzag function that provides a more realistic representation of the deformation states of transverse shear flexible beams than other similar theories. This new zigzag function is unique in that it vanishes at the top and bottom bounding surfaces of a beam. The formulation does not enforce continuity of the transverse shear stress across the beam s cross-section, yet is robust. Two major shortcomings that are inherent in the previous zigzag theories, shear-force inconsistency and difficulties in simulating clamped boundary conditions, and that have greatly limited the utility of these previous theories are discussed in detail. An approach that has successfully resolved these shortcomings is presented herein. This new theory can be readily extended to plate and shell structures, and should be useful for obtaining accurate estimates of structural response of laminated composites.

  9. Correcting the beam centroid motion in an induction accelerator and reducing the beam breakup instability

    NASA Astrophysics Data System (ADS)

    Coleman, J. E.; Ekdahl, C. A.; Moir, D. C.; Sullivan, G. W.; Crawford, M. T.

    2014-09-01

    Axial beam centroid and beam breakup (BBU) measurements were conducted on an 80 ns FWHM, intense relativistic electron bunch with an injected energy of 3.8 MV and current of 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 coupling of the beam centroid motion to the BBU instability and validate the theory of this coupling for the first time. Time resolved centroid measurements indicate a reduction in the BBU amplitude, ⟨ξ⟩, of 19% and a reduction in the BBU growth rate (Γ) of 4% by reducing beam centroid misalignments ˜50% throughout the accelerator. An investigation into the contribution of the misaligned elements is made. An alignment algorithm is presented in addition to a qualitative comparison of experimental and calculated results which include axial beam centroid oscillations, BBU amplitude, and growth with different dipole steering.

  10. A Programmable Beam Shaping System for Tailoring the Profile of High Fluence Laser Beams

    SciTech Connect

    Heebner, J; Borden, M; Miller, P; Stolz, C; Suratwala, T; Wegner, P; Hermann, M; Henesian, M; Haynam, C; Hunter, S; Christensen, K; Wong, N; Seppala, L; Brunton, G; Tse, E; Awwal, A; Franks, M; Marley, E; Williams, K; Scanlan, M; Budge, T; Monticelli, M; Walmer, D; Dixit, S; Widmayer, C; Wolfe, J; Bude, J; McCarty, K; DiNicola, J

    2010-11-10

    Customized spatial light modulators have been designed and fabricated for use as precision beam shaping devices in fusion class laser systems. By inserting this device in a low-fluence relay plane upstream of the amplifier chain, 'blocker' obscurations can be programmed into the beam profile to shadow small isolated flaws on downstream optical components that might otherwise limit the system operating energy. In this two stage system, 1920 x 1080 bitmap images are first imprinted on incoherent, 470 nm address beams via pixilated liquid crystal on silicon (LCoS) modulators. To realize defined masking functions with smooth apodized shapes and no pixelization artifacts, address beam images are projected onto custom fabricated optically-addressable light valves. Each valve consists of a large, single pixel liquid cell in series with a photoconductive Bismuth silicon Oxide (BSO) crystal. The BSO crystal enables bright and dark regions of the address image to locally control the voltage supplied to the liquid crystal layer which in turn modulates the amplitude of the coherent beams at 1053 nm. Valves as large as 24 mm x 36 mm have been fabricated with low wavefront distortion (<0.5 waves) and antireflection coatings for high transmission (>90%) and etalon suppression to avoid spectral and temporal ripple. This device in combination with a flaw inspection system and optic registration strategy represents a new approach for extending the operational lifetime of high fluence laser optics.

  11. Measuring electron beam polarization

    NASA Astrophysics Data System (ADS)

    Napolitano, J.

    1992-12-01

    A two-hour discussion session was held on electron beam polarimetry including representatives from Halls A, B, and C. Presentations included a description of an existing Mo/ller polarimeter at the MIT-Bates laboratory, plans for Mo/ller polarimeters in Halls A and B, and a Compton (i.e., ``laser backscatter'') polarimeter planned for Hall A. This paper is a summary of those discussions.

  12. Proton beam therapy facility

    SciTech Connect

    Not Available

    1984-10-09

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

  13. Beam-Material Interaction

    SciTech Connect

    Mokhov, N. V.; Cerutti, F.

    2016-01-01

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

  14. Ion beam generating apparatus

    DOEpatents

    Brown, Ian G.; Galvin, James

    1987-01-01

    An ion generating apparatus utilizing a vacuum chamber, a cathode and an anode in the chamber. A source of electrical power produces an arc or discharge between the cathode and anode. The arc is sufficient to vaporize a portion of the cathode to form a plasma. The plasma is directed to an extractor which separates the electrons from the plasma, and accelerates the ions to produce an ion beam.

  15. Low energy antiproton beams

    NASA Astrophysics Data System (ADS)

    Klapisch, R.

    1992-04-01

    It was the invention of stochastic cooling by S. Van Meer that has allowed antiproton beams to become a powerful tool for the physicist. As a byproduct of the high energy proton-antiproton collider, a versatile low-energy facility, LEAR has been operating at CERN since 1984. The facility and its characteristics will be described as well as examples of its use for studying fundamental properties of the antiproton and for topics in atomic, nuclear and particle Physics.

  16. Ion beam analysis

    SciTech Connect

    Robertson, J.D. )

    1990-01-01

    A new ion beam analysis facility has recently been installed at a Van de Graaff accelerator. Its use is expected to support many energy and environmental research projects. Material composition and spatial distribution analyses at the facility are based upon Rutherford backscattering spectrometry, particle-induced X-ray emission, and particle-induced gamma-ray emission analysis. An overview of these three techniques is presented in this article.

  17. Laser beam methane detector

    NASA Technical Reports Server (NTRS)

    Hinkley, E. D., Jr.

    1981-01-01

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

  18. Beam Propagation Experimental Study.

    DTIC Science & Technology

    1983-04-01

    and locating the camera next to the FX-100 output switch . The camera trigger was derived directly from the light emitted by the FX-100 output switch ...Instability 20 ASSTRPACT eContinue an reverse aide it necessary and Identify by block number) )A program of extensively diagnosed experiments to investigate ...primary objectives of this research were to measure the rate of erosion of the headIof the beam, and to investigate resistive instabilities, such as

  19. Beam optics test stand

    NASA Astrophysics Data System (ADS)

    Humphries, S., Jr.; Hess, G.

    1988-04-01

    The design and construction of the Beam Optics Test Stand (BOTS) is presented. A variety of computer compatible diagnostics has been developed to facilitate experiments. Extensive theoretical work is presented leading to the identification of two potential methods to correct aberrations in magnetic optics: biased grid arrays and space charge corrected solenoidal lenses. A series of experiments is presented which demonstrates, for the first time, the feasibility of space charge corrected optics.

  20. Partially coherent vectorial nonparaxial beams.

    PubMed

    Duan, Kailiang; Lü, Baida

    2004-10-01

    Generalized vectorial Rayleigh-Sommerfeld diffraction integrals are developed for the cross-spectral-density matrices of spatially partially coherent beams. Using the Gaussian Schell-model (GSM) beam as an example, we derive the expressions for the propagation of cross-spectral-density matrices and intensity of partially coherent vectorial nonparaxial beams, and the corresponding far-field asymptotic forms, beyond the paraxial approximation. The propagation of the vectorial nonparaxial GSM beams are evaluated and analyzed. It is shown that a 3 x 3 cross-spectral-density matrix or a vector theory is required for the exact description of nonparaxial GSM beams.

  1. Monolithical aspherical beam expanding systems

    NASA Astrophysics Data System (ADS)

    Fuchs, U.; Matthias, Sabrina

    2014-10-01

    Beam expanding is a common task, where Galileo telescopes are preferred. However researches and customers have found limitations when using these systems. A new monolithical solution which is based on the usage of only one aspherical component will be presented. It will be shown how to combine up to five monolithical beam expanding systems and to keep the beam quality at diffraction limitation. Insights will be given how aspherical beam expanding systems will help using larger incoming beams and reducing the overall length of such a system. Additionally an add-on element for divergence and wavelength adaption will be presented.

  2. Microscopic Rayleigh Droplet Beams

    NASA Astrophysics Data System (ADS)

    Doak, R. B.

    2005-11-01

    A periodically triggered Rayleigh Droplet Beam (RDB) delivers a perfectly linear and periodic stream of identical, monoenergetic droplets that are phase-locked to the trigger signal. The droplet diameter and spacing are easily adjusted of choice of nozzle diameter and trigger frequency. Any liquid of low viscosity may be emloyed as the beam fluid. Although the field of nanofluidics is expanding rapidly, little effort has yet been devoted to ``external flows'' such as RDB's. At ASU we have generated RDB's of water and methanol down to 2 microns in droplet diameter. Nozzle clogging is the sole impediment to smaller droplets. Microscopic Rayleigh droplet beams offer tremendous potential for fundamental physical measurements, fluid dynamics research, and nanofabrication. This talk will describe the apparatus and techniques used at ASU to generate RDB's (surprisingly simple and inexpensive), discuss the triboelectric phenomena that play a role (surprisingly significant), present some initial experimental fluid dynamics measurements, and briefly survey RDB applications. Our particular interest in RDB's is as microscopic transport systems to deliver hydrated, undenatured proteins into vacuum for structure determination via serial diffraction of x-rays or electrons. This may offer the first general method for structure determination of non-crystallizable proteins.

  3. Infrared Risley beam pointer

    NASA Astrophysics Data System (ADS)

    Harford, Steven T.; Gutierrez, Homero; Newman, Michael; Pierce, Robert; Quakenbush, Tim; Wallace, John; Bornstein, Michael

    2014-03-01

    Ball Aerospace & Technologies Corp. (BATC) has developed a Risley Beam Pointer (RBP) mechanism capable of agile slewing, accurate pointing and high bandwidth. The RBP is comprised of two wedged prisms that offer a wide Field of Regard (FOR) and may be manufactured and operated with diffraction limited optical quality. The tightly packaged mechanism is capable of steering a 4 inch beam over a 60° half angle cone with better than 60 μrad precision. Absolute accuracy of the beam steering is better than 1 mrad. The conformal nature of the RBP makes it an ideal mechanism for use on low altitude aircraft and unmanned aerial vehicles. Unique aspects of the opto-mechanical design include i) thermal compliance to maintain bearing preload and optical figure over a wide temperature range; and ii) packaging of a remote infrared sensor that periodically reports the temperature of both prisms for accurate determination of the index of refraction. The pointing control system operates each prism independently and employs an inner rate loop nested within an outer position loop. Mathematics for the transformation between line-of-sight coordinates and prism rotation are hosted on a 200 MHz microcontroller with just 516 KB of RAM.

  4. Spatial characterization of BNCT beams.

    PubMed

    Marek, M; Viererbl, L

    2004-11-01

    The space distribution of the epithermal neutron flux was determined for the epithermal neutron beams of several NCT facilities in USA (FCB at MIT), Europe (HFR at JRC, Petten; FiR at VTT, Espoo; LVR-15 at NRI, Rez) and Japan (JRR-4 at JAERI, Tokai). Using p-n diodes with (6)Li radiator and the set of Bonner sphere spectrometer (BSS) the beams were quantified in-air. Axial beam profiles along the beam axes and the radial distributions at two distances from the beam aperture were measured. Except for the well-collimated HFR beam, the spatial characteristics of the other studied beams were found generally similar, which results from their similar designs.

  5. Introduction to Ion Beam Therapy

    SciTech Connect

    Martisikova, Maria

    2010-01-05

    Presently, ion beam therapy reaches an increasing interest within the field of radiation therapy, which is caused by the promising clinical results obtained in the last decades. Ion beams enable higher dose conformation to the tumor and increased sparing of the surrounding tissue in comparison to the standard therapy using high energy photons. Heavy ions, like carbon, offer in addition increased biological effectiveness, which makes them suitable for treatment of radioresistant tumors. This contribution gives an overview over the physical and biological properties of ion beams. Common fundamental principles of ion beam therapy are summarized and differences between standard therapy with high energy photons, proton and carbon ion therapy are discussed. The technologies used for the beam production and delivery are introduced, with emphasis to the differences between passive and active beam delivery systems. The last part concentrates on the quality assurance in ion therapy. Specialties of dosimetry in medical ion beams are discussed.

  6. On the self-consistency of the principle of profile consistency results for sawtoothing tokamak discharges

    SciTech Connect

    Arunasalam, V.; Bretz, N.L.; Efthimion, P.C.; Goldston, R.J.; Grek, B.; Johnson, D.W.; Murakami, M.; McGuire, K.; Rasmussen, D.A.; Stauffer, F.J.

    1989-05-01

    The principle of profile consistency states that for fixed limiter safety factor q/sub a/, there exists unique natural equilibrium profile shapes for the current density j(r), and the electron temperature T/sub e/(r) for any tokamak plasma independent of the shapes of the heating power deposition profiles. The mathematical statement of the three basic consequences of this principle for sawtoothing discharges are: (r/sub 1//a) = F/sub 1/ (1/q/sub a/), /T/sub eo/ = F/sub 2/(1/q/sub a/), and a unique scaling law for the central electron temperature T/sub eo/, where r/sub 1/ is the sawtooth inversion radius and is the volume average T/sub e/. Since for a given T/sub e/(r), the ohmic current j(r) can be deduced from Ohm's law, given the function F/sub 1/, the function F/sub 2/ is uniquely fixed and vice versa. Also given F/sub 1/(1/q/sub a/), the central current density j/sub o/ = (V/sub L//2..pi..bRZ/sub eff/) T/sub eo//sup 3/2/ = (I/sub p//..pi..a/sup 2/) F/sub 3/(q/sub a/), where the function F/sub 3/ = (q/sub a//q/sub o/) is uniquely fixed by F/sub 1/. Here b approx. 6.53 /times/ 10/sup 3/ ln..lambda.., and I/sub p/, V/sub L/, Z/sub eff/, R, a, and q/sub o/ are the plasma current, loop voltage, effective ion charge, major and minor radius, and the central safety factor, respectively. Thus for a fixed j(r) or T/sub e/(r), the set of functions F/sub 1/, F/sub 2/, and F/sub 3/ is uniquely fixed. Further, the principle of profile consistency dictates that this set of functions F/sub 1/, F/sub 2/, and F/sub 3/ remain the same for all sawtoothing discharges in any tokamak regardless of its size, I/sub p/, V/sub L/, B/sub T/, etc. Here, we present a rather complete and detailed theoretical examination of this self-consistency of the measured values of T/sub e/(r), F/sub 1/, F/sub 2/, and F/sub 3/ for sawtoothing TFTR discharges. 55 refs., 15 figs., 1 tab.

  7. 15 CFR 930.39 - Content of a consistency determination.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... (Continued) NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE OCEAN AND COASTAL RESOURCE MANAGEMENT FEDERAL CONSISTENCY WITH APPROVED COASTAL MANAGEMENT PROGRAMS Consistency for Federal... consistent to the maximum extent practicable with the enforceable policies of the management program....

  8. 15 CFR 930.39 - Content of a consistency determination.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... (Continued) NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE OCEAN AND COASTAL RESOURCE MANAGEMENT FEDERAL CONSISTENCY WITH APPROVED COASTAL MANAGEMENT PROGRAMS Consistency for Federal... consistent to the maximum extent practicable with the enforceable policies of the management program....

  9. Electron Beam Diagnostics in Plasmas Based on Electron Beam Ionization

    NASA Astrophysics Data System (ADS)

    Leonhardt, Darrin; Leal-Quiros, Edbertho; Blackwell, David; Walton, Scott; Murphy, Donald; Fernsler, Richard; Meger, Robert

    2001-10-01

    Over the last few years, electron beam ionization has been shown to be a viable generator of high density plasmas with numerous applications in materials modification. To better understand these plasmas, we have fielded electron beam diagnostics to more clearly understand the propagation of the beam as it travels through the background gas and creates the plasma. These diagnostics vary greatly in sophistication, ranging from differentially pumped systems with energy selective elements to metal 'hockey pucks' covered with thin layers of insulation to electrically isolate the detector from the plasma but pass high energy beam electrons. Most importantly, absolute measurements of spatially resolved beam current densities are measured in a variety of pulsed and continuous beam sources. The energy distribution of the beam current(s) will be further discussed, through experiments incorporating various energy resolving elements such as simple grids and more sophisticated cylindrical lens geometries. The results are compared with other experiments of high energy electron beams through gases and appropriate disparities and caveats will be discussed. Finally, plasma parameters are correlated to the measured beam parameters for a more global picture of electron beam produced plasmas.

  10. BATMAN beam properties characterization by the beam emission spectroscopy diagnostic

    SciTech Connect

    Bonomo, F.; Ruf, B.; Schiesko, L.; Fantz, U.; Franzen, P.; Riedl, R.; Wünderlich, D.; Barbisan, M.; Pasqualotto, R.; Serianni, G.; Cristofaro, S.

    2015-04-08

    The ITER neutral beam heating systems are based on the production and acceleration of negative ions (H/D) up to 1 MV. The requirements for the beam properties are strict: a low core beam divergence (< 0.4 °) together with a low source pressure (≤ 0.3 Pa) would permit to reduce the ion losses along the beamline, keeping the stripping particle losses below 30%. However, the attainment of such beam properties is not straightforward. At IPP, the negative ion source testbed BATMAN (BAvarian Test MAchine for Negative ions) allows for deepening the knowledge of the determination of the beam properties. One of the diagnostics routinely used to this purpose is the Beam Emission Spectroscopy (BES): the H{sub α} light emitted in the beam is detected and the corresponding spectra are evaluated to estimate the beam divergence and the stripping losses. The BES number of lines of sight in BATMAN has been recently increased: five horizontal lines of sight providing a vertical profile of the beam permit to characterize the negative ion beam properties in relation to the source parameters. Different methods of H{sub α} spectra analysis are here taken into account and compared for the estimation of the beam divergence and the amount of stripping. In particular, to thoroughly study the effect of the space charge compensation on the beam divergence, an additional hydrogen injection line has been added in the tank, which allows for setting different background pressure values (one order of magnitude, from about 0.04 Pa up to the source pressure) in the beam drift region.

  11. Laser power beaming applications and technology

    NASA Astrophysics Data System (ADS)

    Burke, Robert J.; Cover, Ralph A.; Curtin, Mark S.; Dinius, R.; Lampel, Michael C.

    1994-05-01

    Beaming laser energy to spacecraft has important economic potential. It promises significant reduction in the cost of access to space, for commercial and government missions. While the potential payoff is attractive, existing technologies perform the same missions and the keys to market penetration for power beaming are a competitive cost and a schedule consistent with customers' plans. Rocketdyne is considering these questions in the context of a commercial enterprise -- thus, evaluation of the requirements must be done based on market assessments and recognition that significant private funding will be involved. It is in the context of top level business considerations that the technology requirements are being assessed and the program being designed. These considerations result in the essential elements of the development program. Since the free electron laser is regarded as the `long pole in the tent,' this paper summarizes Rocketdyne's approach for a timely, cost-effective program to demonstrate an FEL capable of supporting an initial operating capability.

  12. Generation of filamentary structures by beam-plasma interaction

    SciTech Connect

    Wang, X.Y.; Lin, Y.

    2006-05-15

    The previous simulations by Wang and Lin [Phys. Plasmas. 10, 3528 (2003)] showed that filaments, frequently observed in space plasmas, can form via the interaction between an ion beam and a background plasma. In this study, the physical mechanism for the generation of the filaments is investigated by a two-dimensional hybrid simulation, in which a field-aligned ion beam with relative beam density n{sub b}=0.1 and beam velocity V{sub b}=10V{sub A} is initiated in a uniform plasma. Right-hand nonresonant ion beam modes, consistent with the linear theory, are found to be dominant in the linear stage of the beam-plasma interaction. In the later nonlinear stage, the nonresonant modes decay and the resonant modes grow through a nonlinear wave coupling. The interaction among the resonant modes leads to the formation of filamentary structures, which are the field-aligned structures (k perpendicular B) of magnetic field B, density, and temperature in the final stage. The filaments are nonlinearly generated in a prey-predator fashion by the parallel and oblique resonant ion beam modes, which meanwhile evolve into two types of shear Alfven modes, with one mainly propagating along the background field B{sub 0} and the other obliquely propagating. The filamentary structures are found to be phase standing in the plasma frame, but their amplitude oscillates with time. In the dominant filament mode, fluctuations in the background ion density, background ion temperature, and beam density are in phase with the fluctuations in B, whereas the significantly enhanced beam temperature is antiphase with B. It is found that the filaments are produced by the interaction of at least two ion beam modes with comparable amplitudes, not by only one single mode, thus their generation mechanism is different from other mechanisms such as the stimulated excitation by the decay of an Alfven wave.

  13. Planck 2013 results. VII. HFI time response and beams

    NASA Astrophysics Data System (ADS)

    Planck Collaboration; Ade, P. A. R.; Aghanim, N.; Armitage-Caplan, C.; Arnaud, M.; Ashdown, M.; Atrio-Barandela, F.; Aumont, J.; Baccigalupi, C.; Banday, A. J.; Barreiro, R. B.; Battaner, E.; Benabed, K.; Benoît, A.; Benoit-Lévy, A.; Bernard, J.-P.; Bersanelli, M.; Bielewicz, P.; Bobin, J.; Bock, J. J.; Bond, J. R.; Borrill, J.; Bouchet, F. R.; Bowyer, J. W.; Bridges, M.; Bucher, M.; Burigana, C.; Cardoso, J.-F.; Catalano, A.; Challinor, A.; Chamballu, A.; Chary, R.-R.; Chiang, H. C.; Chiang, L.-Y.; Christensen, P. R.; Church, S.; Clements, D. L.; Colombi, S.; Colombo, L. P. L.; Couchot, F.; Coulais, A.; Crill, B. P.; Curto, A.; Cuttaia, F.; Danese, L.; Davies, R. D.; de Bernardis, P.; de Rosa, A.; de Zotti, G.; Delabrouille, J.; Delouis, J.-M.; Désert, F.-X.; Diego, J. M.; Dole, H.; Donzelli, S.; Doré, O.; Douspis, M.; Dunkley, J.; Dupac, X.; Efstathiou, G.; Enßlin, T. A.; Eriksen, H. K.; Finelli, F.; Forni, O.; Frailis, M.; Fraisse, A. A.; Franceschi, E.; Galeotta, S.; Ganga, K.; Giard, M.; Giraud-Héraud, Y.; González-Nuevo, J.; Górski, K. M.; Gratton, S.; Gregorio, A.; Gruppuso, A.; Gudmundsson, J. E.; Haissinski, J.; Hansen, F. K.; Hanson, D.; Harrison, D.; Henrot-Versillé, S.; Hernández-Monteagudo, C.; Herranz, D.; Hildebrandt, S. R.; Hivon, E.; Hobson, M.; Holmes, W. A.; Hornstrup, A.; Hou, Z.; Hovest, W.; Huffenberger, K. M.; Jaffe, A. H.; Jaffe, T. R.; Jones, W. C.; Juvela, M.; Keihänen, E.; Keskitalo, R.; Kisner, T. S.; Kneissl, R.; Knoche, J.; Knox, L.; Kunz, M.; Kurki-Suonio, H.; Lagache, G.; Lamarre, J.-M.; Lasenby, A.; Laureijs, R. J.; Lawrence, C. R.; Leonardi, R.; Leroy, C.; Lesgourgues, J.; Liguori, M.; Lilje, P. B.; Linden-Vørnle, M.; López-Caniego, M.; Lubin, P. M.; Macías-Pérez, J. F.; MacTavish, C. J.; Maffei, B.; Mandolesi, N.; Maris, M.; Marshall, D. J.; Martin, P. G.; Martínez-González, E.; Masi, S.; Massardi, M.; Matarrese, S.; Matsumura, T.; Matthai, F.; Mazzotta, P.; McGehee, P.; Melchiorri, A.; Mendes, L.; Mennella, A.; Migliaccio, M.; Mitra, S.; Miville-Deschênes, M.-A.; Moneti, A.; Montier, L.; Morgante, G.; Mortlock, D.; Munshi, D.; Murphy, J. A.; Naselsky, P.; Nati, F.; Natoli, P.; Netterfield, C. B.; Nørgaard-Nielsen, H. U.; Noviello, F.; Novikov, D.; Novikov, I.; Osborne, S.; Oxborrow, C. A.; Paci, F.; Pagano, L.; Pajot, F.; Paoletti, D.; Pasian, F.; Patanchon, G.; Perdereau, O.; Perotto, L.; Perrotta, F.; Piacentini, F.; Piat, M.; Pierpaoli, E.; Pietrobon, D.; Plaszczynski, S.; Pointecouteau, E.; Polegre, A. M.; Polenta, G.; Ponthieu, N.; Popa, L.; Poutanen, T.; Pratt, G. W.; Prézeau, G.; Prunet, S.; Puget, J.-L.; Rachen, J. P.; Reinecke, M.; Remazeilles, M.; Renault, C.; Ricciardi, S.; Riller, T.; Ristorcelli, I.; Rocha, G.; Rosset, C.; Roudier, G.; Rowan-Robinson, M.; Rusholme, B.; Sandri, M.; Santos, D.; Sauvé, A.; Savini, G.; Scott, D.; Shellard, E. P. S.; Spencer, L. D.; Starck, J.-L.; Stolyarov, V.; Stompor, R.; Sudiwala, R.; Sureau, F.; Sutton, D.; Suur-Uski, A.-S.; Sygnet, J.-F.; Tauber, J. A.; Tavagnacco, D.; Terenzi, L.; Tomasi, M.; Tristram, M.; Tucci, M.; Umana, G.; Valenziano, L.; Valiviita, J.; Van Tent, B.; Vielva, P.; Villa, F.; Vittorio, N.; Wade, L. A.; Wandelt, B. D.; Yvon, D.; Zacchei, A.; Zonca, A.

    2014-11-01

    This paper characterizes the effective beams, the effective beam window functions and the associated errors for the Planck High Frequency Instrument (HFI) detectors. The effective beam is theangular response including the effect of the optics, detectors, data processing and the scan strategy. The window function is the representation of this beam in the harmonic domain which is required to recover an unbiased measurement of the cosmic microwave background angular power spectrum. The HFI is a scanning instrument and its effective beams are the convolution of: a) the optical response of the telescope and feeds; b) the processing of the time-ordered data and deconvolution of the bolometric and electronic transfer function; and c) the merging of several surveys to produce maps. The time response transfer functions are measured using observations of Jupiter and Saturn and by minimizing survey difference residuals. The scanning beam is the post-deconvolution angular response of the instrument, and is characterized with observations of Mars. The main beam solid angles are determined to better than 0.5% at each HFI frequency band. Observations of Jupiter and Saturn limit near sidelobes (within 5°) to about 0.1% of the total solid angle. Time response residuals remain as long tails in the scanning beams, but contribute less than 0.1% of the total solid angle. The bias and uncertainty in the beam products are estimated using ensembles of simulated planet observations that include the impact of instrumental noise and known systematic effects. The correlation structure of these ensembles is well-described by five error eigenmodes that are sub-dominant to sample variance and instrumental noise in the harmonic domain. A suite of consistency tests provide confidence that the error model represents a sufficient description of the data. The total error in the effective beam window functions is below 1% at 100 GHz up to multipole ℓ ~ 1500, and below 0.5% at 143 and 217 GHz up to

  14. Optimization of combined electron and photon beams for breast cancer

    NASA Astrophysics Data System (ADS)

    Xiong, W.; Li, J.; Chen, L.; Price, R. A.; Freedman, G.; Ding, M.; Qin, L.; Yang, J.; Ma, C.-M.

    2004-05-01

    Recently, intensity-modulated radiation therapy and modulated electron radiotherapy have gathered a growing interest for the treatment of breast and head and neck tumours. In this work, we carried out a study to combine electron and photon beams to achieve differential dose distributions for multiple target volumes simultaneously. A Monte Carlo based treatment planning system was investigated, which consists of a set of software tools to perform accurate dose calculation, treatment optimization, leaf sequencing and plan analysis. We compared breast treatment plans generated using this home-grown optimization and dose calculation software for different treatment techniques. Five different planning techniques have been developed for this study based on a standard photon beam whole breast treatment and an electron beam tumour bed cone down. Technique 1 includes two 6 MV tangential wedged photon beams followed by an anterior boost electron field. Technique 2 includes two 6 MV tangential intensity-modulated photon beams and the same boost electron field. Technique 3 optimizes two intensity-modulated photon beams based on a boost electron field. Technique 4 optimizes two intensity-modulated photon beams and the weight of the boost electron field. Technique 5 combines two intensity-modulated photon beams with an intensity-modulated electron field. Our results show that technique 2 can reduce hot spots both in the breast and the tumour bed compared to technique 1 (dose inhomogeneity is reduced from 34% to 28% for the target). Techniques 3, 4 and 5 can deliver a more homogeneous dose distribution to the target (with dose inhomogeneities for the target of 22%, 20% and 9%, respectively). In many cases techniques 3, 4 and 5 can reduce the dose to the lung and heart. It is concluded that combined photon and electron beam therapy may be advantageous for treating breast cancer compared to conventional treatment techniques using tangential wedged photon beams followed by a boost

  15. Yersinia pestis requires the 2-component regulatory system OmpR-EnvZ to resist innate immunity during the early and late stages of plague.

    PubMed

    Reboul, Angéline; Lemaître, Nadine; Titecat, Marie; Merchez, Maud; Deloison, Gaspard; Ricard, Isabelle; Pradel, Elizabeth; Marceau, Michaël; Sebbane, Florent

    2014-11-01

    Plague is transmitted by fleas or contaminated aerosols. To successfully produce disease, the causal agent (Yersinia pestis) must rapidly sense and respond to rapid variations in its environment. Here, we investigated the role of 2-component regulatory systems (2CSs) in plague because the latter are known to be key players in bacterial adaptation to environmental change. Along with the previously studied PhoP-PhoQ system, OmpR-EnvZ was the only one of Y. pestis' 23 other 2CSs required for production of bubonic, septicemic, and pneumonic plague. In vitro, OmpR-EnvZ was needed to counter serum complement and leukocytes but was not required for the secretion of antiphagocyte exotoxins. In vivo, Y. pestis lacking OmpR-EnvZ did not induce an early immune response in the skin and was fully virulent in neutropenic mice. We conclude that, throughout the course of Y. pestis infection, OmpR-EnvZ is required to counter toxic effectors secreted by polymorphonuclear leukocytes in the tissues.

  16. Studies of the beam extraction system of the GTS-LHC electron cyclotron resonance ion source at CERN

    SciTech Connect

    Toivanen, V. Küchler, D.

    2016-02-15

    The 14.5 GHz GTS-LHC Electron Cyclotron Resonance Ion Source (ECRIS) provides multiply charged heavy ion beams for the CERN experimental program. The GTS-LHC beam formation has been studied extensively with lead, argon, and xenon beams with varied beam extraction conditions using the ion optical code IBSimu. The simulation model predicts self-consistently the formation of triangular and hollow beam structures which are often associated with ECRIS ion beams, as well as beam loss patterns which match the observed beam induced markings in the extraction region. These studies provide a better understanding of the properties of the extracted beams and a way to diagnose the extraction system performance and limitations, which is otherwise challenging due to the lack of direct diagnostics in this region and the limited availability of the ion source for development work.

  17. Studies of the beam extraction system of the GTS-LHC electron cyclotron resonance ion source at CERN.

    PubMed

    Toivanen, V; Küchler, D

    2016-02-01

    The 14.5 GHz GTS-LHC Electron Cyclotron Resonance Ion Source (ECRIS) provides multiply charged heavy ion beams for the CERN experimental program. The GTS-LHC beam formation has been studied extensively with lead, argon, and xenon beams with varied beam extraction conditions using the ion optical code IBSimu. The simulation model predicts self-consistently the formation of triangular and hollow beam structures which are often associated with ECRIS ion beams, as well as beam loss patterns which match the observed beam induced markings in the extraction region. These studies provide a better understanding of the properties of the extracted beams and a way to diagnose the extraction system performance and limitations, which is otherwise challenging due to the lack of direct diagnostics in this region and the limited availability of the ion source for development work.

  18. Mechanical Design of a High Energy Beam Absorber for the Advanced Superconducting Test Accelerator (ASTA) at Fermilab

    SciTech Connect

    Baffes, C.; Church, M.; Leibfritz, J.; Oplt, S.; Rakhno, I.; /Fermilab

    2012-05-10

    A high energy beam absorber has been built for the Advanced Superconducting Test Accelerator (ASTA) at Fermilab. In the facility's initial configuration, an electron beam will be accelerated through 3 TTF-type or ILC-type SRF cryomodules to an energy of 750MeV. The electron beam will be directed to one of multiple downstream experimental and diagnostic beam lines and then deposited in one of two beam absorbers. The facility is designed to accommodate up to 6 cryomodules, which would produce a 75kW beam at 1.5GeV; this is the driving design condition for the beam absorbers. The beam absorbers consist of water-cooled graphite, aluminum and copper layers contained in a helium-filled enclosure. This paper describes the mechanical implementation of the beam absorbers, with a focus on thermal design and analysis. The potential for radiation-induced degradation of the graphite is discussed.

  19. Laser steering of particle beams: Refraction and reflection ofparticle beams

    SciTech Connect

    Esarey, Eric; Katsouleas, T.; Mori, W.B.; Dodd, E.; Lee, S.; Hemker, R.; Clayton, C.; Joshi, C.

    1999-11-01

    The co-propagation of an intense particle beam with an ionizing laser beam in a working gas/plasma is considered. When the axes of the laser and particle beam are not aligned, then asymmetric plasma lensing results in a net dipole field acting on the particle beam. The particle beam can be steered or bent (as well as focused) by steering the laser. An analogy is made between the bending of the particle beam by collective effects at a plasma boundary and the refraction or reflection of light at an interface. This mechanism of particle steering may be of interest in applications for which permanent magnets are inconvenient of a fast turn on is required. 3-D particle-in-cell simulations and relevance to a recent experiment are discussed.

  20. Plasma-beam traps and radiofrequency quadrupole beam coolers.

    PubMed

    Maggiore, M; Cavenago, M; Comunian, M; Chirulotto, F; Galatà, A; De Lazzari, M; Porcellato, A M; Roncolato, C; Stark, S; Caruso, A; Longhitano, A; Cavaliere, F; Maero, G; Paroli, B; Pozzoli, R; Romé, M

    2014-02-01

    Two linear trap devices for particle beam manipulation (including emittance reduction, cooling, control of instabilities, dust dynamics, and non-neutral plasmas) are here presented, namely, a radiofrequency quadrupole (RFQ) beam cooler and a compact Penning trap with a dust injector. Both beam dynamics studies by means of dedicated codes including the interaction of the ions with a buffer gas (up to 3 Pa pressure), and the electromagnetic design of the RFQ beam cooler are reported. The compact multipurpose Penning trap is aimed to the study of multispecies charged particle samples, primarily electron beams interacting with a background gas and/or a micrometric dust contaminant. Using a 0.9 T solenoid and an electrode stack where both static and RF electric fields can be applied, both beam transport and confinement operations will be available. The design of the apparatus is presented.