Lexan Linear Shaped Charge Holder with Magnets and Backing Plate

Science.gov (United States)

Maples, Matthew W.; Dutton, Maureen L.; Hacker, Scott C.; Dean, Richard J.; Kidd, Nicholas; Long, Chris; Hicks, Robert C.

2013-01-01

A method was developed for cutting a fabric structural member in an inflatable module, without damaging the internal structure of the module, using linear shaped charge. Lexan and magnets are used in a charge holder to precisely position the linear shaped charge over the desired cut area. Two types of charge holders have been designed, each with its own backing plate. One holder cuts fabric straps in the vertical configuration, and the other charge holder cuts fabric straps in the horizontal configuration.

Space Charge Mitigation by Hollow Bunches

CERN Multimedia

Oeftiger, AO

2014-01-01

To satisfy the requirements of the HL-LHC (High Luminosity Large Hadron Collider), the LHC injector chain will need to supply a higher brightness, i.e. deliver the same transverse beam emittances \\epsilon_{x,y} while providing a higher intensity N. However, a larger number of particles per bunch enhances space charge effects. One approach to mitigate the impact of space charge is to change the longitudinal phase space distribution: hollow bunches feature a depleted bunch centre and a densely populated periphery. Thus, the spatial line density maximum is depressed which ultimately decreases the tune spread imposed by space charge. Therefore, a higher intensity can be accepted while keeping the same overall space charge tune shift. 3 different methods to create hollow bunches in the PSBooster are simulated.

A fast charge integrating and shaping circuit

International Nuclear Information System (INIS)

Kulka, Z.; Szoncso, F.

1990-01-01

The development of a low cost fast charge integrating and shaping circuit (FCISC) was motivated by the need for an interface between the photomultipliers of an existing hadronic calorimeter and recently developed new readout electronics designed to match the output of small ionization chambers for the upgraded UA1 detector at the CERN proton-antiproton collider. This paper describes the design principles of gated and ungated charge integrating and shaping circuits. An FCISC prototype using discrete components was made and its properties were determined with a computerized test setup. Finally an SMD implementation of the FCISC is presented and the performance is reported. (orig.)

Space-charge compensation of highly charged ion beam from laser ion source

International Nuclear Information System (INIS)

Kondrashev, S.A.; Collier, J.; Sherwood, T.R.

1996-01-01

The problem of matching an ion beam delivered by a high-intensity ion source with an accelerator is considered. The experimental results of highly charged ion beam transport with space-charge compensation by electrons are presented. A tungsten thermionic cathode is used as a source of electrons for beam compensation. An increase of ion beam current density by a factor of 25 is obtained as a result of space-charge compensation at a distance of 3 m from the extraction system. The process of ion beam space-charge compensation, requirements for a source of electrons, and the influence of recombination losses in a space-charge-compensated ion beam are discussed. (author)

Longitudinal holes in debunched particle beams in storage rings, perpetuated by space-charge forces

Directory of Open Access Journals (Sweden)

Shane Koscielniak

2001-04-01

Full Text Available Stationary, self-consistent, and localized longitudinal density perturbations on an unbunched charged-particle beam, which are solutions of the nonlinearized Vlasov-Poisson equation, have recently received some attention. In particular, we address the case that space charge is the dominant longitudinal impedance and the storage ring operates below transition energy so that the negative mass instability is not an explanation for persistent beam structure. Under the customary assumption of a bell-shaped steady-state distribution, about which the expansion is made, the usual wave theory of Keil and Schnell for perturbations on unbunched beams predicts that self-sustaining perturbations are possible only (below transition if the impedance is inductive (or resistive or if the bell shape is inverted. Space charge gives a capacitive impedance. Nevertheless, we report numerous experimental measurements made at the CERN Proton Synchrotron Booster that plainly show the longevity of holelike structures in coasting beams. We shall also report on computer simulations of boosterlike beams that provide compelling evidence that it is space-charge force which perpetuates the holes. We shall show that the localized solitonlike structures, i.e., holes, decouple from the steady-state distribution and that they are simple solutions of the nonlinearized time-independent Vlasov equation. We have derived conditions for stationarity of holes that satisfy the requirement of self-consistency; essentially, the relation between the momentum spread and depth of the holes is given by the Hamiltonian—with the constraint that the phase-space density be high enough to support the solitons. The stationarity conditions have scaling laws similar to the Keil-Schnell criteria except that the charge and momentum spread of the hole replaces that of the beam.

Single-Bunch Stability With Direct Space Charge

CERN Multimedia

Oeftiger, Adrian

2017-01-01

Previous studies have shown the suppressing effect of direct space charge on impedance-driven head-tail instabilities. The present work investigates transverse stability for the HL-LHC scenario based on our macro-particle simulation tool PyHEADTAIL using realistic bunch distributions. The impact of selfconsistent modelling is briefly discussed for non-linear space charge forces. We study how space charge pushes the instability threshold for the transverse mode coupling instability (TMCI) occurring between mode 0 and -1. Next we consider finite chromaticity: in absence of space charge, the impedance model predicts head-tail instabilities. For a selected case below TMCI threshold at Q0 = 5, we demonstrate the stabilising effect of space charge. Finally, we compare simulation results to past LHC measurements.

High density thermite mixture for shaped charge ordnance disposal

Directory of Open Access Journals (Sweden)

Tamer Elshenawy

2017-10-01

Full Text Available The effect of thermite mixture based on aluminum and ferric oxides for ammunition neutralization has been studied and tested. Thermochemical calculations have been carried out for different percentage of Al using Chemical Equilibrium Code to expect the highest performance thermite mixture used for shaped charge ordnance disposal. Densities and enthalpy of different formulations have been calculated and demonstrated. The optimized thermite formulation has been prepared experimentally using cold iso-static pressing technique, which exhibited relatively high density and high burning rate thermite mixture. The produced green product compacted powder mixture was tested against small caliber shaped charge bomblet for neutralization. Theoretical and experimental results showed that the prepared thermite mixture containing 33% of aluminum as a fuel with ferric oxide can be successfully used for shaped charge ordnance disposal.

Space charge tracking code for a synchrotron accelerator

Energy Technology Data Exchange (ETDEWEB)

Ottinger, M.B.; Tajima, T. [Univ. of Texas, Austin, TX (United States); Hiramoto, K. [Hitachi Ltd., Hitachi, Ibaraki (Japan). Hitachi Research Lab.

1997-06-01

An algorithm has been developed to compute particle tracking, including self-consistent space charge effects for synchrotron accelerators. In low-energy synchrotrons space charge plays a central role in enhancing emittance of the beam. The space charge effects are modeled by mutually interacting (through the Coulombic force) N cylindrical particles (2-{1/2}-dimensional dynamics) whose axis is in the direction of the equilibrium particle flow. On the other hand, their interaction with synchrotron lattice magnets is treated with the thin-lens approximation and in a fully 3-dimensional way. Since the existing method to treat space charge fully self-consistently involved 3-D space charge effect computation, the present method allows far more realistic physical parameters and runs in far shorter time (about 1/20). Some examples on space charge induced instabilities are presented.

Space-charge-limit instabilities in electron beams

International Nuclear Information System (INIS)

Coutsias, E.A.; Sullivan, D.J.

1983-01-01

The method of characteristics and multiple-scaling perturbation techniques are used to study the space-charge instability of electron beams. It is found that the stable oscillating state (virtual cathode) created when the space-charge limit is exceeded is similar to a collisionless shock wave. The oscillatory solution originates at the bifurcation point of two unstable steady states. Complementary behavior (virtual anode) results when an ion beam exceeds its space-charge limit. The virtual cathode can also exist in the presence of a neutralizing heavy-ion background. The Pierce instability, where the electron and ion charge densities are equal, is a special case of this broader class. Estimates of the nonlinear growth rate of the instability at the space-charge limit are given

Charge distributions in transverse coordinate space and in impact parameter space

Energy Technology Data Exchange (ETDEWEB)

Hwang, Dae Sung [Department of Physics, Sejong University, Seoul 143-747 (Korea, Republic of)], E-mail: dshwang@slac.stanford.edu; Kim, Dong Soo [Department of Physics, Kangnung National University, Kangnung 210-702 (Korea, Republic of); Kim, Jonghyun [Department of Physics, Sejong University, Seoul 143-747 (Korea, Republic of)

2008-11-27

We study the charge distributions of the valence quarks inside nucleon in the transverse coordinate space, which is conjugate to the transverse momentum space. We compare the results with the charge distributions in the impact parameter space.

Charge distributions in transverse coordinate space and in impact parameter space

OpenAIRE

Hwang, Dae Sung; Kim, Dong Soo; Kim, Jonghyun

2008-01-01

We study the charge distributions of the valence quarks inside nucleon in the transverse coordinate space, which is conjugate to the transverse momentum space. We compare the results with the charge distributions in the impact parameter space.

Dielectric sample with two-layer charge distribution for space charge calibration purposes

DEFF Research Database (Denmark)

Holbøll, Joachim; Henriksen, Mogens; Rasmussen, C.

2002-01-01

In the present paper is described a dielectric test sample with two very narrow concentrations of bulk charges, achieved by two internal electrodes not affecting the acoustical properties of the sample, a fact important for optimal application of most space charge measuring systems. Space charge...

Direct convertor based upon space charge effects

International Nuclear Information System (INIS)

Gitomer, S.J.

1977-01-01

A device capable of converting directly the kinetic energy of charged particles into electrical energy is considered. The device differs from earlier ones (such as Post's periodic focus electrostatic direct convertor) in that it makes use of the space charge repulsion in a high density charged particle beam. The beam is directed into a monotonic decelerating electrostatic field of a several-stage planar-finned structure. The collector fins coincide with vacuum equipotential surfaces. Space charge blowup of the beam directs particles onto various collector fins. The energy efficiency of a 4-stage device has been determined using a numberical simulation approach. We find that efficiencies approaching 75 percent are possible. An approximate scaling law is derived for the space charge based direct converter and a comparison is made to the periodic focus direct convertor. We find the space charge based direct convertor to be superior to a number of ways

Booted domain wall and charged Kaigorodov space

International Nuclear Information System (INIS)

Cai Ronggen

2003-01-01

The Kaigorodov space is a homogeneous Einstein space and it describes a pp-wave propagating in anti-de Sitter space. It is conjectured in the literature that M-theory or string theory on the Kaigorodov space times a compact manifold is dual to a conformal field theory in an infinitely-boosted frame with constant momentum density. In this Letter we present a charged generalization of the Kaigorodov space by boosting a non-extremal charged domain wall to the ultrarelativity limit where the boost velocity approaches the speed of light. The finite boost of the domain wall solution gives the charged generalization of the Carter-Novotny-Horsky metric. We study the thermodynamics associated with the charged Carter-Novotny-Horsky space and discuss its relation to that of the static black domain walls and its implications in the domain wall/QFT (quantum field theory) correspondence

Space-charge calculations in synchrotrons

Energy Technology Data Exchange (ETDEWEB)

Machida, S.

1993-05-01

One obvious bottleneck of achieving high luminosity in hadron colliders, such as the Superconducting Super Collider (SSC), is the beam emittance growth, due to space-charge effects in low energy injector synchrotrons. Although space-charge effects have been recognized since the alternating-gradient synchrotron was invented, and the Laslett tune shift usually calculated to quantify these effects, our understanding of the effects is limited, especially when the Laslett tune shift becomes a large fraction of the integer. Using the Simpsons tracking code, which we developed to study emittance preservation issues in proton synchrotrons, we investigated space-charge effects in the SSC Low Energy Booster (LEB). We observed detailed dependence on parameters such as beam intensity, initial emittance, injection energy, lattice function, and longitudinal motion. A summary of those findings, as well as the tracking technique we developed for the study, are presented.

Longitudinal Space Charge in the SPS

CERN Document Server

Lasheen, Alexandre

2016-01-01

Longitudinal instabilities due to the SPS beam coupling impedance are a major issue for future projects and it is essential to have an accurate SPS impedance model to study them. The longitudinal space charge effect can be modelled by a pure reactive impedance and should also be included in simulations as it may have an impact at low energy. In this Note, the effect of the longitudinal space charge in the SPS is evaluated by taking into account the variation of the transverse beam size and vacuum chamber geometry along the ring. Scaling laws are used to investigate what are the most important parameters for the evaluation of the longitudinal space charge impedance.

Nonlinear space charge effect of bunched beam in linac

International Nuclear Information System (INIS)

Chen Yinbao

1992-02-01

The nonlinear space charge effect due to the nonuniform particle density distribution in bunched beam of a linac is discussed. The formulae of nonlinear space charge effect and nonlinear focusing forces were derived for the bunched beam with Kapchinskij-Vladimirskij (K-V) distribution, waterbag (WB) distribution, parabolic (PA) distribution, and Gauss (GA) distribution in both of the space charge disk model and space charge cylinder model in the waveguide of a linac

Fundamental geodesic deformations in spaces of treelike shapes

DEFF Research Database (Denmark)

Feragen, Aasa; Lauze, Francois Bernard; Nielsen, Mads

2010-01-01

This paper presents a new geometric framework for analysis of planar treelike shapes for applications such as shape matching, recognition and morphology, using the geometry of the space of treelike shapes. Mathematically, the shape space is given the structure of a stratified set which...... is a quotient of a normed vector space with a metric inherited from the vector space norm. We give examples of geodesic paths in tree-space corresponding to fundamental deformations of small trees, and discuss how these deformations are key building blocks for understanding deformations between larger trees....

WSN-Based Space Charge Density Measurement System.

Science.gov (United States)

Deng, Dawei; Yuan, Haiwen; Lv, Jianxun; Ju, Yong

2017-01-01

It is generally acknowledged that high voltage direct current (HVDC) transmission line endures the drawback of large area, because of which the utilization of cable for space charge density monitoring system is of inconvenience. Compared with the traditional communication network, wireless sensor network (WSN) shows advantages in small volume, high flexibility and strong self-organization, thereby presenting great potential in solving the problem. Additionally, WSN is more suitable for the construction of distributed space charge density monitoring system as it has longer distance and higher mobility. A distributed wireless system is designed for collecting and monitoring the space charge density under HVDC transmission lines, which has been widely applied in both Chinese state grid HVDC test base and power transmission projects. Experimental results of the measuring system demonstrated its adaptability in the complex electromagnetic environment under the transmission lines and the ability in realizing accurate, flexible, and stable demands for the measurement of space charge density.

Shape space exploration of constrained meshes

KAUST Repository

Yang, Yongliang; Yang, Yijun; Pottmann, Helmut; Mitra, Niloy J.

2011-01-01

We present a general computational framework to locally characterize any shape space of meshes implicitly prescribed by a collection of non-linear constraints. We computationally access such manifolds, typically of high dimension and co-dimension, through first and second order approximants, namely tangent spaces and quadratically parameterized osculant surfaces. Exploration and navigation of desirable subspaces of the shape space with regard to application specific quality measures are enabled using approximants that are intrinsic to the underlying manifold and directly computable in the parameter space of the osculant surface. We demonstrate our framework on shape spaces of planar quad (PQ) meshes, where each mesh face is constrained to be (nearly) planar, and circular meshes, where each face has a circumcircle. We evaluate our framework for navigation and design exploration on a variety of inputs, while keeping context specific properties such as fairness, proximity to a reference surface, etc. © 2011 ACM.

Shape space exploration of constrained meshes

KAUST Repository

Yang, Yongliang

2011-12-12

We present a general computational framework to locally characterize any shape space of meshes implicitly prescribed by a collection of non-linear constraints. We computationally access such manifolds, typically of high dimension and co-dimension, through first and second order approximants, namely tangent spaces and quadratically parameterized osculant surfaces. Exploration and navigation of desirable subspaces of the shape space with regard to application specific quality measures are enabled using approximants that are intrinsic to the underlying manifold and directly computable in the parameter space of the osculant surface. We demonstrate our framework on shape spaces of planar quad (PQ) meshes, where each mesh face is constrained to be (nearly) planar, and circular meshes, where each face has a circumcircle. We evaluate our framework for navigation and design exploration on a variety of inputs, while keeping context specific properties such as fairness, proximity to a reference surface, etc. © 2011 ACM.

Study of space--charge effect by computer

International Nuclear Information System (INIS)

Sasaki, T.

1982-01-01

The space--charge effect in high density electron beams (beam current approx.2 μA) focused by a uniform magnetic field is studied computationally. On an approximation of averaged space-- charge force, a theory of trajectory displacements of beam electrons is developed. The theory shows that the effect of the averaged space--charge force appears as a focal length stretch. The theory is confirmed not only qualitatively but also quantitatively by simulations. Empirical formulas for the trajectory displacement and the energy spread are presented. A comparison between the empirical formulas and some theoretical formulas is made, leading to a severe criticism on the theories of energy spreads

Self-excitation of space charge waves

DEFF Research Database (Denmark)

Lyuksyutov, Sergei; Buchhave, Preben; Vasnetsov, Mikhail

1997-01-01

We report a direct observation of space charge waves in photorefractive crystals with point group 23 (sillenites) based on their penetration into an area with uniform light illumination. It is shown experimentally that the quality factor of the waves increases substantially with respect to what c...... current theory predicts [B. Sturman el al., Appl. Phys. A 55, 235 (1992)]. This results in the appearance of strong spontaneous beams caused by space charge wave self-excitation....

Incorporating space charge in the transverse phase-space matching and tomography at PITZ

Energy Technology Data Exchange (ETDEWEB)

Kourkafas, Georgios

2015-11-15

The ever-expanding achievements in the field of particle accelerators push their specifications to very demanding levels. The performance of many modern applications depends on their ability to be operated with high bunch charges confined in small volumes. However, the consequence of increased intensity is strong space-charge forces, which perplex the beam manipulation and undermine the beam quality. As a result, reliable methods are needed to control and measure the accelerated particles under these extraordinary conditions. The phase space tomography is a diagnostic technique which can reveal details of the transverse beam parameters for a wide range of intensities and energies, with minimal influence from the machine instabilities, in a quasi non-destructive way. The accuracy of this method relies on the precise knowledge and control of the particle dynamics under the influence of space charge in different stages of the measurement. On the one hand, the matching of the beam to the measurement's design transverse parameters requires a procedure which efficiently compensates the effects of space charge. Depending on the structure of the magnetic lattice, different aspects of these effects prevail, therefore different strategies have to be developed. On the other hand, the impact of the space-charge forces on the phase-space transformations during the data acquisition has to be included in the model which is used for the tomographic reconstruction. The aim of this thesis is to provide and test time-efficient solutions for the incorporation of space charge in the transverse beam matching and phase space tomography.

Incorporating space charge in the transverse phase-space matching and tomography at PITZ

International Nuclear Information System (INIS)

Kourkafas, Georgios

2015-11-01

The ever-expanding achievements in the field of particle accelerators push their specifications to very demanding levels. The performance of many modern applications depends on their ability to be operated with high bunch charges confined in small volumes. However, the consequence of increased intensity is strong space-charge forces, which perplex the beam manipulation and undermine the beam quality. As a result, reliable methods are needed to control and measure the accelerated particles under these extraordinary conditions. The phase space tomography is a diagnostic technique which can reveal details of the transverse beam parameters for a wide range of intensities and energies, with minimal influence from the machine instabilities, in a quasi non-destructive way. The accuracy of this method relies on the precise knowledge and control of the particle dynamics under the influence of space charge in different stages of the measurement. On the one hand, the matching of the beam to the measurement's design transverse parameters requires a procedure which efficiently compensates the effects of space charge. Depending on the structure of the magnetic lattice, different aspects of these effects prevail, therefore different strategies have to be developed. On the other hand, the impact of the space-charge forces on the phase-space transformations during the data acquisition has to be included in the model which is used for the tomographic reconstruction. The aim of this thesis is to provide and test time-efficient solutions for the incorporation of space charge in the transverse beam matching and phase space tomography.

Resonance behavior in the presence of space charge

International Nuclear Information System (INIS)

Month, M.; Weng, W.T.

1983-01-01

An analysis is presented of the resonance behavior of particle beams in the presence of space charge fields. Since self-consistent requirements are ignored, the results describe onset or early behavior. It is shown that in a beam of uniform current resonances excited by magnetic field errors are stabilized by the detuning effect of the self-field space charge force. This situation is changed when a radiofrequency accelerating field is applied. As beam bunching results after rf turn-on, the space charge force becomes modulated along the bunches, vanishing at the ends. At these regions of small or vanishing space charge, stabilization from non-linear detuning tends to disappear, thus leaving particles susceptible to resonance blow-up. This picture of the effect of beam bunching can be studied by considering the phase space structure for particles at different positions along the bunches. A somewhat unusual conclusion is made on the use of this analysis to model beam capture in a synchrotron at low energy

Charge collection and space charge distribution in neutron-irradiated epitaxial silicon detectors

International Nuclear Information System (INIS)

Poehlsen, Thomas

2010-04-01

In this work epitaxial n-type silicon diodes with a thickness of 100 μm and 150 μm are investigated. After neutron irradiation with fluences between 10 14 cm -2 and 4 x 10 15 cm -2 annealing studies were performed. CV-IV curves were taken and the depletion voltage was determined for different annealing times. All investigated diodes with neutron fluences greater than 2 x 10 14 cm -2 showed type inversion due to irradiation. Measurements with the transient current technique (TCT) using a pulsed laser were performed to investigate charge collection effects for temperatures of -40 C, -10 C and 20 C. The charge correction method was used to determine the effective trapping time τ eff . Inconsistencies of the results could be explained by assuming field dependent trapping times. A simulation of charge collection could be used to determine the field dependent trapping time τ eff (E) and the space charge distribution in the detector bulk. Assuming a linear field dependence of the trapping times and a linear space charge distribution the data could be described. Indications of charge multiplication were seen in the irradiated 100 μm thick diodes for all investigated fluences at voltages above 800 V. The space charge distribution extracted from TCT measurements was compared to the results of the CV measurements and showed good agreement. (orig.)

Equilibrium phase-space distributions and space charge limits in linacs

International Nuclear Information System (INIS)

Lysenko, W.P.

1977-10-01

Limits on beam current and emittance in proton and heavy ion linear accelerators resulting from space charge forces are calculated. The method involves determining equilibrium distributions in phase space using a continuous focusing, no acceleration, model in two degrees of freedom using the coordinates r and z. A nonlinear Poisson equation must be solved numerically. This procedure is a matching between the longitudinal and transverse directions to minimize the effect of longitudinal-transverse coupling which is believed to be the main problem in emittance growth due to space charge in linacs. Limits on the Clinton P. Anderson Meson Physics Facility (LAMPF) accelerator performance are calculated as an example. The beam physics is described by a few space charge parameters so that accelerators with different physical parameters can be compared in a natural way. The main result of this parameter study is that the requirement of a high-intensity beam is best fulfilled with a low-frequency accelerator whereas the requirement of a high-brightness beam is best fulfilled with a high-frequency accelerator

Three-dimensional space-charge calculation method

International Nuclear Information System (INIS)

Lysenko, W.P.; Wadlinger, E.A.

1980-09-01

A method is presented for calculating space-charge forces on individual particles in a particle tracing simulation code. Poisson's equation is solved in three dimensions with boundary conditions specified on an arbitrary surface. When the boundary condition is defined by an impressed radio-frequency field, the external electric fields as well as the space-charge fields are determined. A least squares fitting procedure is used to calculate the coefficients of expansion functions, which need not be orthogonal nor individually satisfy the boundary condition

Conductivity and Space Charges in PE with Additives

DEFF Research Database (Denmark)

Holbøll, Joachim; Henriksen, Mogens; Hjerrild, J.

2003-01-01

temperatures. Space charge formation under an applied electrical field of 20 kV/mm was investigated by means of the pulse-electro-acoustic method (PEA) at room temperature. The results were compared to space charge formation and conductivity in common LDPE. The measurements showed considerable differences...... between materials and only minor influence of crosslinking process and the addition of antioxidant with respect to the electrical properties of the material. Possible correlations between conductivity and space charge formation are discussed in the paper. The relevance of the findings for application...

Pulse shape discrimination with silicon detectors using charge and current-sensitive preamplifiers

Energy Technology Data Exchange (ETDEWEB)

Hamrita, H.; Rauly, E.; Blumenfeld, Y.; Borderie, B.; Chabot, M.; Edelbruck, P.; Lavergne, L.; Le Bris, J.; Le Neindre, N.; Richard, A.; Rivet, M.F.; Scarpaci, J.A.; Barbey, S.; Becheva, E.; Bzyl, F.R.; D' Esesquelles, P.; Galichet, E.; Lalu, G.; Martinet, G.; Pierre, S. [Institut de Physique Nucleaire, IN2P3-CNRS, 91 - Orsay (France); Legou, Th.; Tillier, J.; Bocage, F.; Bougault, R.; Carniol, B.; Cussol, D.; Etasse, D.; Grevy, S.; Lopez, O.; Tamain, B.; Vient, E. [Caen Univ., LPC, IN2P3-CNRS, ENSI, 14 - Caen (France); Galichet, E. [Conservatoire National des Arts et Metier, 75 - Paris (France); Guinet, D.; Lautesse, Ph. [Villeurbanne Univ., Institut de Physique Nucleaire, IN2P3-CNRS, 69 (France); Lanzalone, G. [Catania Univ., INFN, Laboratori Nazionali del Sud and Dipartimento di Fisica e Astronomia, (Italy); Politi, G. [Catania Univ., INFN, Sezione di Catania and Dipartimento di Fisica e Astronomia (Italy); Rosato, E. [Napoli, Univ., Dipt. di Scienze Fisiche e Sezione INFN (Italy)

2003-07-01

For the first time shapes of current pulses from light charged particles and carbon ions are presented. Capabilities for pulse shape discrimination techniques are demonstrated. In this work, charge and current-sensitive preamplifier prototypes for nuclear structure and dynamics experiments have been developed and tested with the aim of improving PSD (pulse shape discrimination) method by studying in detail current signal shapes from particles and ions over a large energy range. Note that current signal shapes have been recently used in atomic cluster studies to identify partitions of carbon cluster fragmentation. The paper is organized as follows. Section 2 is devoted to characterization of preamplifiers. In section 3, results of on beam tests will be presented, discussed and compared to a simple simulation.

Space charge effects and electronic bistability

International Nuclear Information System (INIS)

Ruffini, A.; Strumia, F.; Tommasi, O.

1996-01-01

The excitation of metastable states in an atomic beam apparatus by means of electron collision is a widespread technique. The authors have observed a large bistable behaviour in apparatus designed to provide an intense and collimated beam of metastable helium by excitation with orthogonally impinging electrons. This bistable behaviour largely affects the efficiency of the apparatus and is therefore worth of being carefully investigated. The apparatus has an electrode configuration equivalent to that of a tetrode valve with large intergrid distances. The bistability consists in a hysteresis cycle in the curve of the anode current vs. grid voltage. Experimental measurements, supported by a simple theoretical model and by numerical simulation, stress out the crucial role played by space charge effects for the onset of bistability. A comparison with previous observations of this phenomenon is given. Spontaneous current oscillations with various shapes have been recorded in one of the two curves of the hysteresis cycle

Klystron - Space-charge limited flow, guns, Perveance

International Nuclear Information System (INIS)

Isagawa, S.

1999-01-01

This paper treats Thermionic emission, Cathode as an e - emitter, Space-charge limited effect and 3/2 power law, Perveance, Beam spread due to space charge, Pierce guns, Magnetically immersed guns, Method of gun design including simulations, and Examples, mainly treating E3786, which attendees will operate above 1 MW-CW in a practical exercise course at KEK. (author). 74 refs

Minimizing the energy spread within a single bunch by shaping its charge distribution

International Nuclear Information System (INIS)

Loew, G.A.; Wang, J.W.

1985-03-01

It has been known for some time that partial compensation of the longitudinal wake field effects can be obtained for any bunch by placing it ahead of the accelerating crest (in space), thereby letting the positive rising sinusoidal field offset the negative beam loading field. The work presented in this paper shows that it is possible to obtain complete compensation, i.e., to reduce the energy spread essentially to zero by properly shaping the longitudinal charge distribution of the bunch and by placing it at the correct position on the wave. 3 refs., 5 figs., 3 tabs

Charge collection and space charge distribution in neutron-irradiated epitaxial silicon detectors

Energy Technology Data Exchange (ETDEWEB)

Poehlsen, Thomas

2010-04-15

In this work epitaxial n-type silicon diodes with a thickness of 100 {mu}m and 150 {mu}m are investigated. After neutron irradiation with fluences between 10{sup 14} cm{sup -2} and 4 x 10{sup 15} cm{sup -2} annealing studies were performed. CV-IV curves were taken and the depletion voltage was determined for different annealing times. All investigated diodes with neutron fluences greater than 2 x 10{sup 14} cm{sup -2} showed type inversion due to irradiation. Measurements with the transient current technique (TCT) using a pulsed laser were performed to investigate charge collection effects for temperatures of -40 C, -10 C and 20 C. The charge correction method was used to determine the effective trapping time {tau}{sub eff}. Inconsistencies of the results could be explained by assuming field dependent trapping times. A simulation of charge collection could be used to determine the field dependent trapping time {tau}{sub eff}(E) and the space charge distribution in the detector bulk. Assuming a linear field dependence of the trapping times and a linear space charge distribution the data could be described. Indications of charge multiplication were seen in the irradiated 100 {mu}m thick diodes for all investigated fluences at voltages above 800 V. The space charge distribution extracted from TCT measurements was compared to the results of the CV measurements and showed good agreement. (orig.)

Dynamic space charge behaviour in polymeric DC cables

DEFF Research Database (Denmark)

Rasmussen, Claus Nygaard; Holbøll, Joachim; Henriksen, Mogens

2002-01-01

The use of extruded insulation for DC cables involves a risk of local electric field enhancement, caused by a space charge build-up within the dielectric. In this work, the theory of charge generation and transport in polymers is applied in a numerical computer model in order to predict...... the formation and transport of space charges in a polymeric dielectric. The model incorporates the processes of field assisted electron-hole pair generation from impurity atoms, trapping and charge injection at the electrodes. Its aim has been to study the field- and temperature dependent dynamic behaviour...

Nonlinear periodic space-charge waves in plasma

International Nuclear Information System (INIS)

Kovalev, V. A.

2009-01-01

A solution is obtained in the form of coupled nonlinear periodic space-charge waves propagating in a magnetoactive plasma. The wave spectrum in the vicinity of the critical point, where the number of harmonics increases substantially, is found to fall with harmonic number as ∝ s -1/3 . Periodic space-charge waves are invoked to explain the zebra pattern in the radio emission from solar flares.

Stability of anisotropic beams with space charge

International Nuclear Information System (INIS)

Hofmann, I.

1997-07-01

We calculate coherent frequencies and stability properties of anisotropic or ''non-equipartitioned'' beams with different focusing constants and emittances in the two transverse directions. Based on the self-consistent Vlasov-Poisson equations the dispersion relations of transverse multipole oscillations with quadrupolar, sextupolar and octupolar symmetry are solved numerically. The eigenfrequencies give the coherent space charge tune shift for linear or nonlinear resonances in circular accelerators. We find that for sufficiently large energy anisotropy some of the eigenmodes become unstable in the space-charge-dominated regime. The properties of these anisotropy instabilities are used to show that ''non-equipartitioned'' beams can be tolerated in high-current linear accelerators. It is only in beams with strongly space-charge-depressed betatron tunes where harmful instabilities leading to emittance exchange should be expected. (orig.)

Modelling of electric tree progression due to space charge modified fields

International Nuclear Information System (INIS)

Seralathan, K E; Mahajan, A; Gupta, Nandini

2008-01-01

Tree initiation and growth require localized field enhancement that results in material erosion and formation of tree channels. Tree progression is linked to partial discharges within the tree tubules, characterized by recurrent periods of activity followed by quiescent states. Charge builds up across the non-conducting tree channels during the inactive regime, and discharge follows. In this work, the role of the space charge modified field during the non-discharging regime in deciding the site of subsequent discharges and thereby shaping tree structures is studied. A simple stochastic model was developed, in order to understand the respective effects of charges trapped on the walls of tree tubules, at channel tips, or in the volume of the dielectric. While some charge distributions are seen to arrest tree growth, others encourage axial growth towards the other electrode, and some aid in producing bushy trees clustered around the needle tip. The effect of carbon deposition within tree channels, making them effectively conducting, was also investigated. The insights gained from the simulations were successfully used to explain tree growth in the laboratory under high- and low-field conditions

Space charge in nanostructure resonances

Science.gov (United States)

Price, Peter J.

1996-10-01

In quantum ballistic propagation of electrons through a variety of nanostructures, resonance in the energy-dependent transmission and reflection probabilities generically is associated with (1) a quasi-level with a decay lifetime, and (2) a bulge in electron density within the structure. It can be shown that, to a good approximation, a simple formula in all cases connects the density of states for the latter to the energy dependence of the phase angles of the eigen values of the S-matrix governing the propagation. For both the Lorentzian resonances (normal or inverted) and for the Fano-type resonances, as a consequence of this eigen value formula, the space charge due to filled states over the energy range of a resonance is just equal (for each spin state) to one electron charge. The Coulomb interaction within this space charge is known to 'distort' the electrical characteristics of resonant nanostructures. In these systems, however, the exchange effect should effectively cancel the interaction between states with parallel spins, leaving only the anti-parallel spin contribution.

Space-Charge-Limited Emission Models for Particle Simulation

Science.gov (United States)

Verboncoeur, J. P.; Cartwright, K. L.; Murphy, T.

2004-11-01

Space-charge-limited (SCL) emission of electrons from various materials is a common method of generating the high current beams required to drive high power microwave (HPM) sources. In the SCL emission process, sufficient space charge is extracted from a surface, often of complicated geometry, to drive the electric field normal to the surface close to zero. The emitted current is highly dominated by space charge effects as well as ambient fields near the surface. In this work, we consider computational models for the macroscopic SCL emission process including application of Gauss's law and the Child-Langmuir law for space-charge-limited emission. Models are described for ideal conductors, lossy conductors, and dielectrics. Also considered is the discretization of these models, and the implications for the emission physics. Previous work on primary and dual-cell emission models [Watrous et al., Phys. Plasmas 8, 289-296 (2001)] is reexamined, and aspects of the performance, including fidelity and noise properties, are improved. Models for one-dimensional diodes are considered, as well as multidimensional emitting surfaces, which include corners and transverse fields.

Space-Charge Effects in a Gas Detector

Energy Technology Data Exchange (ETDEWEB)

Ryutov, D.D.

2010-12-03

Discussion of space-charge effects in a photoluminescence cell that will be used as a nondisruptive total energy monitor at the LCLS facility is presented. Regimes where primary photoelectrons will be confined within the X-ray beam aperture are identified. Effects of the space-charge on the further evolution of the electron and ion populations are discussed. Parameters of the afterglow plasma are evaluated. Conditions under which the detector output will be proportional to the pulse energy are defined.

Charge Transport in Spiro-OMeTAD Investigated through Space-Charge-Limited Current Measurements

Science.gov (United States)

Röhr, Jason A.; Shi, Xingyuan; Haque, Saif A.; Kirchartz, Thomas; Nelson, Jenny

2018-04-01

Extracting charge-carrier mobilities for organic semiconductors from space-charge-limited conduction measurements is complicated in practice by nonideal factors such as trapping in defects and injection barriers. Here, we show that by allowing the bandlike charge-carrier mobility, trap characteristics, injection barrier heights, and the shunt resistance to vary in a multiple-trapping drift-diffusion model, a numerical fit can be obtained to the entire current density-voltage curve from experimental space-charge-limited current measurements on both symmetric and asymmetric 2 ,2',7 ,7' -tetrakis(N ,N -di-4-methoxyphenylamine)-9 ,9' -spirobifluorene (spiro-OMeTAD) single-carrier devices. This approach yields a bandlike mobility that is more than an order of magnitude higher than the effective mobility obtained using analytical approximations, such as the Mott-Gurney law and the moving-electrode equation. It is also shown that where these analytical approximations require a temperature-dependent effective mobility to achieve fits, the numerical model can yield a temperature-, electric-field-, and charge-carrier-density-independent mobility. Finally, we present an analytical model describing trap-limited current flow through a semiconductor in a symmetric single-carrier device. We compare the obtained charge-carrier mobility and trap characteristics from this analytical model to the results from the numerical model, showing excellent agreement. This work shows the importance of accounting for traps and injection barriers explicitly when analyzing current density-voltage curves from space-charge-limited current measurements.

Reduction of space charge breakdown in e-beam irradiated nano/polymethyl methacrylate composites

International Nuclear Information System (INIS)

Zheng Feihu; Zhang Yewen; An Zhenlian; Dong Jianxing; Lei Qingquan

2013-01-01

Fast discharge of numerous space charges in dielectric materials can cause space charge breakdown. This letter reports the role of nanoparticles in affecting space charge breakdown of nano/polymethyl methacrylate composites. Space charge distributions in the composites, implanted by electron beam irradiation, were measured by pressure wave propagation method. The results show that the nanoparticles have significant effects on the isothermal charge decay and space charge breakdown in the nanocomposites. The resistance to space charge breakdown in the nanocomposites is attributed to the combined action of the introduction of deep trapping states and the scattering effect by the added nanoparticles.

Implementation of Space Charge Forces in BimBim

CERN Document Server

Gottlob, Emmanuel; Oeftiger, Adrian

An numerical algorithm is described for the implementation of linearised coherent space charge forces into BimBim, an eigenvalue solver for the coherent modes of oscillation of multibunch beams in the presence of beam coupling impedance, beam-beam, transverse feedback and now space charge effects. First results obtained with the model are described and compared to existing results where applicable.

Influence of Charge Shape and Orientation on the Response of Steel-Concrete Composite Panels

Directory of Open Access Journals (Sweden)

Abraham Christian

2016-09-01

Full Text Available Blast design codes usually generalize the shape of the charge as spherical or hemispherical. However, it was found that the blast overpressure of cylindrical charges differ greatly when compared with relevant analytical results generated with the charges assumed to be spherical. The objective is to use fully coupled 3D multi-material arbitrary Lagrangian Eulerian (MMALE modelling technique in LS Dyna software to simulate the cylindrical charge blast loading. Comparison of spherical and cylindrical charge blast simulation was carried out to show the influence on peak overpressure and total impulse. Two steel-concrete composite specimens were subjected to blast testing under cylinder charges for benchmarking against numerical results. It was found that top detonated, vertical cylinder charge could give much higher blast loading compared to horizontal cylinder charge. The MMALE simulation could generate the pressure loading of various charge shape and orientation to be used for predicting the response of the composite panel.

Effect of surface topography and morphology on space charge packets in polyethylene

International Nuclear Information System (INIS)

Zhou Yuanxiang; Wang Yunshan; Sun Qinghua; Wang Ninghua

2009-01-01

Polyethylene (PE) is a major kind of internal insulating material. With great progresses of space charge measurement technologies in the last three decades, lots of researches are focused on space charge in PE. The heat pressing and annealing condition of polyethylene affect its morphology obviously. During the heat pressing, the surface of PE forms different surface topographies because of different substrate materials. Surface topography has great relation to the epitaxial crystallization layer and influences the space charge characteristic of PE dramatically. This paper studied the formation process of different surface topographies and their micrographic characters in low density polyethylene (LDPE). pulsed electro-acoustic (PEA) method was used to measure the space charge distribution of samples with different surface topographies and morphologies in LDPE. The effect of surface topography and morphology to space charge packet were studied. The surface topography has great influence on space charge packet polarity and morphology has influence on both movement speed rate and polarity of space charge packet.

Low-energy beam transport using space-charge lenses

International Nuclear Information System (INIS)

Meusel, O.; Bechtold, A.; Pozimski, J.; Ratzinger, U.; Schempp, A.; Klein, H.

2005-01-01

Space-charge lenses (SCL) of the Gabor type provide strong cylinder symmetric focusing for low-energy ion beams using a confined nonneutral plasma. They need modest magnetic and electrostatic field strength and provide a short installation length when compared to conventional LEBT-lenses like quadrupoles and magnetic solenoids. The density distribution of the enclosed space charge within the Gabor lens is given by the confinement in transverse and longitudinal directions. In the case of a positive ion beam, the space charge of the confined electron cloud may cause an overcompensation of the ion beam space-charge force and consequently focuses the beam. To investigate the capabilities of an SCL double-lens system for ion beam into an RFQ, a test injector was installed at IAP and put into operation successfully. Furthermore, to study the focusing capabilities of this lens at beam energies up to 500 keV, a high-field Gabor lens was built and installed downstream of the RFQ. Experimental results of the beam injection into the RFQ are presented as well as those of these first bunched beam-focusing tests with the 110 A keV He + beam

Application of Uintah-MPM to shaped charge jet penetration of aluminum

International Nuclear Information System (INIS)

Burghardt, J; Leavy, B; Brannon, R; Guilkey, J; Xue, Z

2010-01-01

The capability of the generalized interpolation material point (GIMP) method in simulation of penetration events is investigated. A series of experiments was performed wherein a shaped charge jet penetrates into a stack of aluminum plates. Electronic switches were used to measure the penetration time history. Flash x-ray techniques were used to measure the density, length, radius and velocity of the shaped charge jet. Simulations of the penetration event were performed using the Uintah MPM/GIMP code with several different models of the shaped charge jet being used. The predicted penetration time history for each jet model is compared with the experimentally observed penetration history. It was found that the characteristics of the predicted penetration were dependent on the way that the jet data are translated to a discrete description. The discrete jet descriptions were modified such that the predicted penetration histories fell very close to the range of the experimental data. In comparing the various discrete jet descriptions it was found that the cumulative kinetic energy flux curve represents an important way of characterizing the penetration characteristics of the jet. The GIMP method was found to be well suited for simulation of high rate penetration events.

Equivalent circuit modeling of space charge dominated magnetically insulated transmission lines

Energy Technology Data Exchange (ETDEWEB)

Hiraoka, Kazuki; Nakajima, Mitsuo; Horioka, Kazuhiko

1997-12-31

A new equivalent circuit model for space charge dominated MITLs (Magnetically Insulated Transmission Lines) was developed. MITLs under high power operation are dominated with space charge current flowing between anode and cathode. Conventional equivalent circuit model does not account for space charge effects on power flow. The model was modified to discuss the power transportation through the high power MITLs. With this model, it is possible to estimate the effects of space charge current on the power flow efficiency, without using complicated particle code simulations. (author). 3 figs., 3 refs.

Stochastic Coulomb interactions in space charge limited electron emission

NARCIS (Netherlands)

Nijkerk, M.D.; Kruit, P.

2004-01-01

A Monte Carlo simulation tool, which was used to evaluate the influence of discrete space charge effects on self-consistent calculations of cathode-ray tube optics, was discussed. It was found that interactions in the space charge cloud affect the electron trajectories such that the velocity

Space-charge dynamics of polymethylmethacrylate under electron beam irradiation

CERN Document Server

Gong, H; Ong, C K

1997-01-01

Space-charge dynamics of polymethylmethacrylate (PMMA) under electron beam irradiation has been investigated employing a scanning electron microscope. Assuming a Gaussian space-charge distribution, the distribution range (sigma) has been determined using a time-resolved current method in conjunction with a mirror image method. sigma is found to increase with irradiation time and eventually attain a stationary value. These observations have been discussed by taking into account radiation-induced conductivity and charge mobility. (author)

Performance of kevlar fibre-reinforced rubber composite armour against shaped-charge jet penetration

OpenAIRE

Zu,Xu-dong; Huang,Zheng-xiang; Zhai,Wen

2015-01-01

AbstractThe protective capability of the Kevlar fibre-reinforced rubber composite armour (KFRRCA) at different obliquities is studied using depth-of-penetration experiments method against a 56 mm-diameter standard-shaped charge. Efficiency factors are calculated to evaluate the protection capability of the KFRRCA at different obliquities. Meanwhile, an X-ray experiment is used to observe the deformation, fracture, and scatter of the shaped-charge jet as it penetrates the composite armour. Fin...

On the use of shape spaces to compare morphometric methods

Directory of Open Access Journals (Sweden)

F. James Rohlf

2000-06-01

Full Text Available Abstract Several methods have been proposed to use differences in configurations of landmark points to measure the amount of shape difference between two structures. Shape difference coefficients ignore differences in the configurations that could be due to the effects of translation, rotation, and scale. One way to understand the differences between these methods is to compare the multidimensional shape spaces corresponding to each coefficient. This paper compares Kendall's shape space, Kendall tangent space, the shape spaces implied by EDMA-I and EDMA-II test statistics, the shape space of log size-scaled inter-landmark distances, and the shape space implied by differences in angles of lines connecting pairs of landmarks. The case of three points in the plane (i.e., landmarks at the vertices of a triangle is given special emphasis because the various shape spaces can be illustrated in just 2 or 3 dimensions. The results of simulalions are shown both for random samples of all possible triangles as well as for normally distributed independent variation at each landmark. Generalizations to studies of more than three landmarks are suggested. It is shown that methods other than those based on Procrustes distances strongly constrain the possible results obtained by ordination analyses, can give misleading results when used in studies of growth and evolutionary trajectories.

Determination of charged particle beam parameters with taking into account of space charge

International Nuclear Information System (INIS)

Ishkhanov, B.S.; Poseryaev, A.V.; Shvedunov, V.I.

2005-01-01

One describes a procedure to determine the basic parameters of a paraxial axially-symmetric beam of charged particles taking account of space charge contribution. The described procedure is based on application of the general equation for beam envelope. Paper presents data on its convergence and resistance to measurement errors. The position determination error of crossover (stretching) and radius of beam in crossover is maximum 15% , while the emittance determination error depends on emittance and space charge correlation. The introduced procedure was used to determine parameters of the available electron gun 20 keV energy beam with 0.64 A current. The derived results turned to agree closely with the design parameters [ru

Performance of kevlar fibre-reinforced rubber composite armour against shaped-charge jet penetration

Directory of Open Access Journals (Sweden)

Xu-dong Zu

Full Text Available AbstractThe protective capability of the Kevlar fibre-reinforced rubber composite armour (KFRRCA at different obliquities is studied using depth-of-penetration experiments method against a 56 mm-diameter standard-shaped charge. Efficiency factors are calculated to evaluate the protection capability of the KFRRCA at different obliquities. Meanwhile, an X-ray experiment is used to observe the deformation, fracture, and scatter of the shaped-charge jet as it penetrates the composite armour. Finally, scanning electron microscopy (SEM is used to analyse the effect of the Kevlar fibre-reinforced rubber for the composite armour to resist jet penetration. The results showed that the KFEECA can be used as additional armour, because it has excellent protection capability, and it can disturb the stability of the middle part of the shaped charge jet (SCJ obviously especially when the armour at 30°and 68° obliquities.

Space-Charge Experiments at the CERN Proton Synchrotron

CERN Document Server

Franchetti, Giuliano; Hofmann, I; Martini, M; Métral, E; Qiang, J; Ryne, D; Steerenberg, R; CFA Beam Dynamics Workshop “High Intensity and Brightness Hadron Beams”

2005-01-01

Benchmarking of the simulation codes used for the design of the next generation of high beam power accelerators is of paramount importance due to the very demanding requirements on the level of beam losses. This is usually accomplished by comparing simulation results against available theories, and more importantly, against experimental observations. To this aim, a number of well-defined test cases, obtained by accurate measurements made in existing machines, are of great interest. Such measurements have been made in the CERN Proton Synchrotron to probe three space-charge effects: (i) transverse emittance blow-up due to space-charge induced crossing of the integer or half-integer stop-band, (ii) space-charge and octupole driven resonance trapping, and (iii) intensity-dependent emittance transfer between the two transverse planes. The last mechanism is discussed in detail in this paper and compared to simulation predictions.

Experimental and numerical studies on penetration of shaped charge into concrete and pebble layered targets

Directory of Open Access Journals (Sweden)

C Wang

2017-09-01

Full Text Available Experiments on penetrating into concrete and pebble layered targets were performed by shaped charge with different cone angles, liner wall thicknesses, length to diameter ratios and charge diameters at different standoffs. Based on the experimental data, the influence of shaped charge’s structural parameters on crater diameter, hole diameter, crater depth and penetration depth was analyzed in detail. Meanwhile, formation and penetration processes of all shaped charges were simulated by AUTODYN software for investigating the more intrinsic mechanisms, in which the numerical models are the same as those set up in the experiments. The results obtained in this paper indicate that there are obvious differences between jetting projectile charge (JPC and explosively formed projectile (EFP in penetrating into multi-layer targets. For the same charge diameter, the values of hole diameter formed by EFP were much larger than JPC. However, for the same standoff, the penetration depth caused by JCP were larger than EFP. The interfacial effect exists in the penetration progress of JPC.

Space-charge effects in Penning ion traps

Science.gov (United States)

Porobić, T.; Beck, M.; Breitenfeldt, M.; Couratin, C.; Finlay, P.; Knecht, A.; Fabian, X.; Friedag, P.; Fléchard, X.; Liénard, E.; Ban, G.; Zákoucký, D.; Soti, G.; Van Gorp, S.; Weinheimer, Ch.; Wursten, E.; Severijns, N.

2015-06-01

The influence of space-charge on ion cyclotron resonances and magnetron eigenfrequency in a gas-filled Penning ion trap has been investigated. Off-line measurements with K39+ using the cooling trap of the WITCH retardation spectrometer-based setup at ISOLDE/CERN were performed. Experimental ion cyclotron resonances were compared with ab initio Coulomb simulations and found to be in agreement. As an important systematic effect of the WITCH experiment, the magnetron eigenfrequency of the ion cloud was studied under increasing space-charge conditions. Finally, the helium buffer gas pressure in the Penning trap was determined by comparing experimental cooling rates with simulations.

Space charge effect in an accelerated beam

Directory of Open Access Journals (Sweden)

G. Stupakov

2008-01-01

Full Text Available It is usually assumed that the space charge effects in relativistic beams scale with the energy of the beam as γ^{-2}, where γ is the relativistic factor. We show that for a beam accelerated in the longitudinal direction there is an additional space charge effect in free space that scales as E/γ, where E is the accelerating field. This field has the same origin as the “electromagnetic mass of the electron” discussed in textbooks on electrodynamics. It keeps the balance between the kinetic energy of the beam and the energy of the electromagnetic field of the beam. We then consider the effect of this field on a beam generated in an rf gun and calculate the energy spread produced by this field in the beam.

EBQ code: Transport of space-charge beams in axially symmetric devices

Science.gov (United States)

Paul, A. C.

1982-11-01

Such general-purpose space charge codes as EGUN, BATES, WODF, and TRANSPORT do not gracefully accommodate the simulation of relativistic space-charged beams propagating a long distance in axially symmetric devices where a high degree of cancellation has occurred between the self-magnetic and self-electric forces of the beam. The EBQ code was written specifically to follow high current beam particles where space charge is important in long distance flight in axially symmetric machines possessing external electric and magnetic field. EBQ simultaneously tracks all trajectories so as to allow procedures for charge deposition based on inter-ray separations. The orbits are treated in Cartesian geometry (position and momentum) with z as the independent variable. Poisson's equation is solved in cylindrical geometry on an orthogonal rectangular mesh. EBQ can also handle problems involving multiple ion species where the space charge from each must be included. Such problems arise in the design of ion sources where different charge and mass states are present.

EBQ code: transport of space-charge beams in axially symmetric devices

International Nuclear Information System (INIS)

Paul, A.C.

1982-11-01

Such general-purpose space charge codes as EGUN, BATES, WOLF, and TRANSPORT do not gracefully accommodate the simulation of relativistic space-charged beams propagating a long distance in axially symmetric devices where a high degree of cancellation has occurred between the self-magnetic and self-electric forces of the beam. The EBQ code was written specifically to follow high current beam particles where space charge is important in long distance flight in axially symmetric machines possessing external electric and magnetic field. EBQ simultaneously tracks all trajectories so as to allow procedures for charge deposition based on inter-ray separations. The orbits are treated in Cartesian geometry (position and momentum) with z as the independent variable. Poisson's equation is solved in cylindrical geometry on an orthogonal rectangular mesh. EBQ can also handle problems involving multiple ion species where the space charge from each must be included. Such problems arise in the design of ion sources where different charge and mass states are present

Numerical study on the matching law between charge caliber and delay time of the rod-shaped explosively formed projectile

Science.gov (United States)

Shen, H. M.; Li, W. B.; Wang, X. M.; Li, W. B.

2017-09-01

To study the application of multi-point initiation technology on shaped charge warhead, numerically simulated the influence of initiating delay time of different charge caliber on detonation wave and performance forming of penetrator. The study found that as charge caliber increased, the allowable initiating delay time also increased. For the commonly used small and medium-charge caliber shaped charge warhead, the charge caliber(Dk ) and the delay time (σ) presented a linear relationship σ = -12.79+1.25Dk . As charge caliber continue increasing, the initiating allowable delay time started to increase exponentially. The study reveals the matching law between charge caliber, initiating delay time and performance forming of penetrator, and it offers guidance for the design of multi-point initiation network for shaped charge.

New design of the pulsed electro-acoustic upper electrode for space charge measurements during electronic irradiation

Energy Technology Data Exchange (ETDEWEB)

Riffaud, J.; Griseri, V.; Berquez, L. [UPS, LAPLACE, Université de Toulouse, 118 Route de Narbonne, Toulouse F-31062, France and CNRS, LAPLACE, Toulouse F-31062 (France)

2016-07-15

The behaviour of space charges injected in irradiated dielectrics has been studied for many years for space industry applications. In our case, the pulsed electro-acoustic method is chosen in order to determine the spatial distribution of injected electrons. The feasibility of a ring-shaped electrode which will allow the measurements during irradiation is presented. In this paper, a computer simulation is made in order to determine the parameters to design the electrode and find its position above the sample. The obtained experimental results on polyethylene naphthalate samples realized during electronic irradiation and through relaxation under vacuum will be presented and discussed.

Progress of Space Charge Research on Oil-Paper Insulation Using Pulsed Electroacoustic Techniques

Directory of Open Access Journals (Sweden)

Chao Tang

2016-01-01

Full Text Available This paper focuses on the space charge behavior in oil-paper insulation systems used in power transformers. It begins with the importance of understanding the space charge behavior in oil-paper insulation systems, followed by the introduction of the pulsed electrostatic technique (PEA. After that, the research progress on the space charge behavior of oil-paper insulation during the recent twenty years is critically reviewed. Some important aspects such as the environmental conditions and the acoustic wave recovery need to be addressed to acquire more accurate space charge measurement results. Some breakthroughs on the space charge behavior of oil-paper insulation materials by the research team at the University of Southampton are presented. Finally, future work on space charge measurement of oil-paper insulation materials is proposed.

Stochastic Coulomb interactions in space charge limited electron emission

International Nuclear Information System (INIS)

Nijkerk, M.D.; Kruit, P.

2004-01-01

Emission models that form the basis of self-consistent field computations make use of the approximation that emitted electrons form a smooth space charge jelly. In reality, electrons are discrete particles that are subject to statistical Coulomb interactions. A Monte Carlo simulation tool is used to evaluate the influence of discrete space charge effects on self-consistent calculations of cathode-ray tube optics. We find that interactions in the space charge cloud affect the electron trajectories such that the velocity distribution is Maxwellian, regardless of the current density. Interactions near the emitter effectively conserve the Maxwellian distribution. The surprising result is that the width of the distribution of transversal velocities does not change. The distribution of longitudinal velocities does broaden, as expected from existing theories

Quadrupole transport experiment with space charge dominated cesium ion beam

International Nuclear Information System (INIS)

Faltens, A.; Keefe, D.; Kim, C.; Rosenblum, S.; Tiefenback, M.; Warwick, A.

1984-08-01

The purpose of the experiment is to investigate the beam current transport limit in a long quadrupole-focussed transport channel in the space charge dominated region where the space charge defocussing force is almost as large as the average focussing force of the channel

Space charge effects in proton linear accelerators

International Nuclear Information System (INIS)

Prome, Michel

1971-01-01

Space charge difficulties are relatively well known because of the inconveniences they cause, but the physical mechanisms by which they operate are obscure; an attempt was made to explain some of these mechanisms. The method chosen involves a numerical simulation of the beam; computer programs describing beam dynamics with space charge are presented; they are used to check results obtained elsewhere. A series of experiments was performed demonstrating that coupling phenomena produce an equalization of r. m. s. velocities in the 3 directions; new quantity (sort of hyper-emittance) is introduced: its growth between the input and output of a given linac is proportional to the beam intensity. (author) [fr

Space charge beam dynamics studies for a pulsed spallation source accelerator

Energy Technology Data Exchange (ETDEWEB)

Cho, Y.; Lessner, E.

1995-12-31

Feasibility studies for 2-GeV, 1-MW and 10-GeV, 5-MW rapid cycling synchrotrons (RCS) for spallation neutron sources have been completed. Both synchrotrons operate at a repetition rate of 30 Hz, and accelerate 1.04 {times} 10{sup 14} protons per pulse. The injection energy of the 2-GeV ring is 400 MeV, and the 10-GeV RCS accepts the beam from the 2-GeV machine. Work performed to-date includes calculation of the longitudinal space charge effects in the 400-MeV beam transfer line, and of both longitudinal and transverse space charge effects during the injection, capture and acceleration processes in the two rings. Results of space charge calculations in the rings led to proper choices of the working points and of rf voltage programs that prevents beam loss. Space charge effects in the 2-GeV synchrotron, in both transverse and longitudinal phase space, have major impact on the design due to the fact that the injection energy is 400 MeV. The design achieves the required performance while alleviating harmful effects due to space charge.

Simulation of space charge effects in a synchrotron

International Nuclear Information System (INIS)

Machida, Shinji; Ikegami, Masanori

1998-01-01

We have studied space charge effects in a synchrotron with multi-particle tracking in 2-D and 3-D configuration space (4-D and 6-D phase space, respectively). First, we will describe the modelling of space charge fields in the simulation and a procedure of tracking. Several ways of presenting tracking results will be also mentioned. Secondly, it is discussed as a demonstration of the simulation study that coherent modes of a beam play a major role in beam stability and intensity limit. The incoherent tune in a resonance condition should be replaced by the coherent tune. Finally, we consider the coherent motion of a beam core as a driving force of halo formation. The mechanism is familiar in linac, and we apply it in a synchrotron

Space-charge Effect on Electroresistance in Metal-Ferroelectric-Metal capacitors

Science.gov (United States)

Tian, Bo Bo; Liu, Yang; Chen, Liu Fang; Wang, Jian Lu; Sun, Shuo; Shen, Hong; Sun, Jing Lan; Yuan, Guo Liang; Fusil, Stéphane; Garcia, Vincent; Dkhil, Brahim; Meng, Xiang Jian; Chu, Jun Hao

2015-12-01

Resistive switching through electroresistance (ER) effect in metal-ferroelectric-metal (MFM) capacitors has attracted increasing interest due to its potential applications as memories and logic devices. However, the detailed electronic mechanisms resulting in large ER when polarisation switching occurs in the ferroelectric barrier are still not well understood. Here, ER effect up to 1000% at room temperature is demonstrated in C-MOS compatible MFM nanocapacitors with a 8.8 nm-thick poly(vinylidene fluoride) (PVDF) homopolymer ferroelectric, which is very promising for silicon industry integration. Most remarkably, using theory developed for metal-semiconductor rectifying contacts, we derive an analytical expression for the variation of interfacial barrier heights due to space-charge effect that can interpret the observed ER response. We extend this space-charge model, related to the release of trapped charges by defects, to MFM structures made of ferroelectric oxides. This space-charge model provides a simple and straightforward tool to understand recent unusual reports. Finally, this work suggests that defect-engineering could be an original and efficient route for tuning the space-charge effect and thus the ER performances in future electronic devices.

Three-dimensional space charge distribution measurement in electron beam irradiated PMMA

International Nuclear Information System (INIS)

Imaizumi, Yoichi; Suzuki, Ken; Tanaka, Yasuhiro; Takada, Tatsuo

1996-01-01

The localized space charge distribution in electron beam irradiated PMMA was investigated using pulsed electroacoustic method. Using a conventional space charge measurement system, the distribution only in the depth direction (Z) can be measured assuming the charges distributed uniformly in the horizontal (X-Y) plane. However, it is difficult to measure the distribution of space charge accumulated in small area. Therefore, we have developed the new system to measure the three-dimensional space charge distribution using pulsed electroacoustic method. The system has a small electrode with a diameter of 1mm and a motor-drive X-Y stage to move the sample. Using the data measured at many points, the three-dimensional distribution were obtained. To estimate the system performance, the electron beam irradiated PMMA was used. The electron beam was irradiated from transmission electron microscope (TEM). The depth of injected electron was controlled using the various metal masks. The measurement results were compared with theoretically calculated values of electron range. (author)

Radar observations of ion cyclotron waves associated with two barium shaped-charge releases

International Nuclear Information System (INIS)

Providakes, J.; Swartz, W.E.; Kelley, M.C.; Djuth, F.T.; Noble, S.; Jost, R.J.

1990-01-01

A 50-MHz Doppler radar interferometer and a 138-MHz Doppler radar were operated from Kennedy Space Center to study 3-m and 1-m plasma waves associated with two shaped-charged barium releases from Wallops Island, Virginia, on May 13, 1986. During the first release, interferometer and Doppler power spectral studies showed the existence of short-lived ( + EIC waves were unstable for field-aligned electron drifts greater than 0.7υ the at the altitude of 510 km in a multispecies (O + , NO + , or similarly O 2 + ) ionospheric plasma. The authors interpret the 30-Hz waves seen by the two radars far above the release as strong electrostatic ion cyclotron waves generated by intense field-aligned currents associated with the barium stream acting like an MHD generator coupled to the ionospheres

Particle identification via pulse-shape discrimination with a charge-integrating ADC

International Nuclear Information System (INIS)

Heltsley, J.H.; Brandon, L.; Galonsky, A.; Heilbronn, L.; Remington, B.A.; Langer, S.; Van der Molen, A.; Yurkon, J.; Michigan State Univ., East Lansing; Kasagi, J.

1988-01-01

A charge-integrating ADC has been used to sample the intensity in two different time regions of a pulse and thus to sense the shape of the pulse. This idea has been applied to produce neutron/γ-ray discrimination from pulses in a liquid scintillation detector. Optimization of available parameters yields good pulse-shape discrimination for pulses greater than those produced by 100 keV electrons. The method uses only general purpose electronics. (orig.)

Course Notes: United States Particle Accelerator School Beam Physics with Intense Space-Charge

International Nuclear Information System (INIS)

Barnard, J.J.; Lund, S.M.

2008-01-01

The purpose of this course is to provide a comprehensive introduction to the physics of beams with intense space charge. This course is suitable for graduate students and researchers interested in accelerator systems that require sufficient high intensity where mutual particle interactions in the beam can no longer be neglected. This course is intended to give the student a broad overview of the dynamics of beams with strong space charge. The emphasis is on theoretical and analytical methods of describing the acceleration and transport of beams. Some aspects of numerical and experimental methods will also be covered. Students will become familiar with standard methods employed to understand the transverse and longitudinal evolution of beams with strong space charge. The material covered will provide a foundation to design practical architectures. In this course, we will introduce you to the physics of intense charged particle beams, focusing on the role of space charge. The topics include: particle equations of motion, the paraxial ray equation, and the Vlasov equation; 4-D and 2-D equilibrium distribution functions (such as the Kapchinskij-Vladimirskij, thermal equilibrium, and Neuffer distributions), reduced moment and envelope equation formulations of beam evolution; transport limits and focusing methods; the concept of emittance and the calculation of its growth from mismatches in beam envelope and from space-charge non-uniformities using system conservation constraints; the role of space-charge in producing beam halos; longitudinal space-charge effects including small amplitude and rarefaction waves; stable and unstable oscillation modes of beams (including envelope and kinetic modes); the role of space charge in the injector; and algorithms to calculate space-charge effects in particle codes. Examples of intense beams will be given primarily from the ion and proton accelerator communities with applications from, for example, heavy-ion fusion, spallation

Space charge dynamic of irradiated cyanate ester/epoxy at cryogenic temperatures

Science.gov (United States)

Wang, Shaohe; Tu, Youping; Fan, Linzhen; Yi, Chengqian; Wu, Zhixiong; Li, Laifeng

2018-03-01

Glass fibre reinforced polymers (GFRPs) have been widely used as one of the main electrical insulating structures for superconducting magnets. A new type of GFRP insulation material using cyanate ester/epoxy resin as a matrix was developed in this study, and the samples were irradiated by Co-60 for 1 MGy and 5 MGy dose. Space charge distributed within the sample were tested using the pulsed electroacoustic method, and charge concentration was found at the interfaces between glass fibre and epoxy resin. Thermally stimulated current (TSC) and dc conduction current were also tested to evaluate the irradiation effect. It was supposed that charge mobility and density were suppressed at the beginning due to the crosslinking reaction, and for a higher irradiation dose, molecular chain degradation dominated and led to more sever space charge accumulation at interfaces which enhance the internal electric field higher than the external field, and transition field for conduction current was also decreased by irradiation. Space charge dynamic at cryogenic temperature was revealed by conduction current and TSC, and space charge injection was observed for the irradiated samples at 225 K, which was more obvious for the irradiated samples.

Space charge and magnet error simulations for the SNS accumulator ring

International Nuclear Information System (INIS)

Beebe-Wang, J.; Fedotov, A.V.; Wei, J.; Machida, S.

2000-01-01

The effects of space charge forces and magnet errors in the beam of the Spallation Neutron Source (SNS) accumulator ring are investigated. In this paper, the focus is on the emittance growth and halo/tail formation in the beam due to space charge with and without magnet errors. The beam properties of different particle distributions resulting from various injection painting schemes are investigated. Different working points in the design of SNS accumulator ring lattice are compared. The simulations in close-to-resonance condition in the presence of space charge and magnet errors are presented. (author)

Chaos in Time-Dependent Space-Charge Potentials

CERN Document Server

Betzel, Gregory T; Sideris, Ioannis V

2005-01-01

We consider a spherically symmetric, homologously breathing, space-charge-dominated beam bunch in the spirit of the particle-core model. The question we ask is: How does the time dependence influence the population of chaotic orbits? The static beam has zero chaotic orbits; the equation of particle motion is integrable up to quadrature. This is generally not true once the bunch is set into oscillation. We quantify the population of chaotic orbits as a function of space charge and oscillation amplitude (mismatch). We also apply a newly developed measure of chaos, one that distinguishes between regular, sticky, and wildly chaotic orbits, to characterize the phase space in detail. We then introduce colored noise into the system and show how its presence modifies the dynamics. One finding is that, despite the presence of a sizeable population of chaotic orbits, halo formation in the homologously breathing beam is much less prevalent than in an envelope-matched counterpart wherein an internal collective mode is ex...

Benchmarking of 3D space charge codes using direct phase space measurements from photoemission high voltage dc gun

Directory of Open Access Journals (Sweden)

Ivan V. Bazarov

2008-10-01

Full Text Available We present a comparison between space charge calculations and direct measurements of the transverse phase space of space charge dominated electron bunches from a high voltage dc photoemission gun followed by an emittance compensation solenoid magnet. The measurements were performed using a double-slit emittance measurement system over a range of bunch charge and solenoid current values. The data are compared with detailed simulations using the 3D space charge codes GPT and Parmela3D. The initial particle distributions were generated from measured transverse and temporal laser beam profiles at the photocathode. The beam brightness as a function of beam fraction is calculated for the measured phase space maps and found to approach within a factor of 2 the theoretical maximum set by the thermal energy and the accelerating field at the photocathode.

Study of static properties of magnetron-type space charges

International Nuclear Information System (INIS)

Delcroix, Jean-Loup

1953-01-01

This research thesis reports an in-depth analysis of physical properties of static regimes to address the issue of space charges. This theoretical study of the Hull magnetron is followed by the description of experiments on the Hull magnetron which highlight transitions between the different regimes. Then, another theoretical approach aims at generalising the magnetron theory, based on other types of magnetron theory (general equations of magnetron-type space charges, inverted Hull magnetron theory, circular field magnetron theory)

Maximizing Ion Current by Space Charge Neutralization using Negative Ions and Dust Particles

International Nuclear Information System (INIS)

Smirnov, A.; Raitses, Y.; Fisch, N.J.

2005-01-01

Ion current extracted from an ion source (ion thruster) can be increased above the Child-Langmuir limit if the ion space charge is neutralized. Similarly, the limiting kinetic energy density of the plasma flow in a Hall thruster might be exceeded if additional mechanisms of space charge neutralization are introduced. Space charge neutralization with high-mass negative ions or negatively charged dust particles seems, in principle, promising for the development of a high current or high energy density source of positive light ions. Several space charge neutralization schemes that employ heavy negatively charged particles are considered. It is shown that the proposed neutralization schemes can lead, at best, only to a moderate but nonetheless possibly important increase of the ion current in the ion thruster and the thrust density in the Hall thruster

Transverse Schottky spectra and beam transfer functions of coasting ion beams with space charge

International Nuclear Information System (INIS)

Paret, Stefan

2010-01-01

A study of the transverse dynamics of coasting ion beams with moderate space charge is presented in this work. From the dispersion relation with linear space charge, an analytic model describing the impact of space charge on transverse beam transfer functions (BTFs) and the stability limits of a beam is derived. The dielectric function obtained in this way is employed to describe the transverse Schottky spectra with linear space charge as well. The difference between the action of space charge and impedances is highlighted. The setup and the results of an experiment performed in the heavy ion synchrotron SIS-18 at GSI to detect space-charge effects at different beam intensities are explicated. The measured transverse Schottky spectra and BTFs are compared with the linear space-charge model. The stability diagrams constructed from the BTFs are presented. The space-charge parameters evaluated from the Schottky and BTF measurements are compared with estimations based on measured beam parameters. The impact of collective effects on the Schottky and BTF diagnostics is also investigated through numerical simulations. For this purpose the self-field of beams with linear and non-linear transverse density-distributions is computed on a twodimensional grid. The noise of the random particle distribution causes fluctuations of the dipole moment of the beam which produce the Schottky spectrum. BTFs are simulated by exciting the beam with transverse kicks. The simulation results are used to verify the space-charge model. (orig.)

Transverse Schottky spectra and beam transfer functions of coasting ion beams with space charge

Energy Technology Data Exchange (ETDEWEB)

Paret, Stefan

2010-02-22

A study of the transverse dynamics of coasting ion beams with moderate space charge is presented in this work. From the dispersion relation with linear space charge, an analytic model describing the impact of space charge on transverse beam transfer functions (BTFs) and the stability limits of a beam is derived. The dielectric function obtained in this way is employed to describe the transverse Schottky spectra with linear space charge as well. The difference between the action of space charge and impedances is highlighted. The setup and the results of an experiment performed in the heavy ion synchrotron SIS-18 at GSI to detect space-charge effects at different beam intensities are explicated. The measured transverse Schottky spectra and BTFs are compared with the linear space-charge model. The stability diagrams constructed from the BTFs are presented. The space-charge parameters evaluated from the Schottky and BTF measurements are compared with estimations based on measured beam parameters. The impact of collective effects on the Schottky and BTF diagnostics is also investigated through numerical simulations. For this purpose the self-field of beams with linear and non-linear transverse density-distributions is computed on a twodimensional grid. The noise of the random particle distribution causes fluctuations of the dipole moment of the beam which produce the Schottky spectrum. BTFs are simulated by exciting the beam with transverse kicks. The simulation results are used to verify the space-charge model. (orig.)

Internal electric fields of electrolytic solutions induced by space-charge polarization

Science.gov (United States)

Sawada, Atsushi

2006-10-01

The dielectric dispersion of electrolytic solutions prepared using chlorobenzene as a solvent and tetrabutylammonium tetraphenylborate as a solute is analyzed in terms of space-charge polarization in order to derive the ionic constants, and the Stokes radius obtained is discussed in comparison with the values that have been measured by conductometry. A homogeneous internal electric field is assumed for simplicity in the analysis of the space-charge polarization. The justification of the approximation by the homogeneous field is discussed from two points of view: one is the accuracy of the Stokes radius value observed and the other is the effect of bound charges on electrodes in which they level the highly inhomogeneous field, which has been believed in the past. In order to investigate the actual electric field, numerical calculations based on the Poisson equation are carried out by considering the influence of the bound charges. The variation of the number of bound charges with time is clarified by determining the relaxation function of the dielectric constant attributed to the space-charge polarization. Finally, a technique based on a two-field approximation, where homogeneous and hyperbolic fields are independently applied in relevant frequency ranges, is introduced to analyze the space-charge polarization of the electrolytic solutions, and further improvement of the accuracy in the determination of the Stokes radius is achieved.

SCAP - a Shaped Charge Analysis Program: user's manual for SCAP 1. 0

Energy Technology Data Exchange (ETDEWEB)

Robinson, A.C.

1985-04-01

The basic modeling and format for a shaped charge analysis program, SCAP, is described. The code models the motion of liner elements due to explosive loading, jet formation, jet breakup and target penetration through application of a series of analytical approximations. The structure of the code is intended to provide flexibility in shaped charge device and target configurations and in modeling techniques. The code is designed for interactive use and produces both printed and plotted output. Examples of code output are given and compared with experimental data. 19 refs., 13 figs.

High-order space charge effects using automatic differentiation

International Nuclear Information System (INIS)

Reusch, Michael F.; Bruhwiler, David L.

1997-01-01

The Northrop Grumman Topkark code has been upgraded to Fortran 90, making use of operator overloading, so the same code can be used to either track an array of particles or construct a Taylor map representation of the accelerator lattice. We review beam optics and beam dynamics simulations conducted with TOPKARK in the past and we present a new method for modeling space charge forces to high-order with automatic differentiation. This method generates an accurate, high-order, 6-D Taylor map of the phase space variable trajectories for a bunched, high-current beam. The spatial distribution is modeled as the product of a Taylor Series times a Gaussian. The variables in the argument of the Gaussian are normalized to the respective second moments of the distribution. This form allows for accurate representation of a wide range of realistic distributions, including any asymmetries, and allows for rapid calculation of the space charge fields with free space boundary conditions. An example problem is presented to illustrate our approach

Investigating shape and space in mathematics: A case study | Kotze ...

African Journals Online (AJOL)

Evidence was obtained regarding mathematics teachers' and mathematics learners' knowledge of space and shape. Problems experienced in concept formation in geometry were investigated and analysed. An account is provided of how teachers and learners responded to problems related to space and shape.

High density thermite mixture for shaped charge ordnance disposal

OpenAIRE

Tamer Elshenawy; Salah Soliman; Ahmed Hawass

2017-01-01

The effect of thermite mixture based on aluminum and ferric oxides for ammunition neutralization has been studied and tested. Thermochemical calculations have been carried out for different percentage of Al using Chemical Equilibrium Code to expect the highest performance thermite mixture used for shaped charge ordnance disposal. Densities and enthalpy of different formulations have been calculated and demonstrated. The optimized thermite formulation has been prepared experimentally using col...

The role of space charge compensation for ion beam extraction and ion beam transport (invited)

International Nuclear Information System (INIS)

Spädtke, Peter

2014-01-01

Depending on the specific type of ion source, the ion beam is extracted either from an electrode surface or from a plasma. There is always an interface between the (almost) space charge compensated ion source plasma, and the extraction region in which the full space charge is influencing the ion beam itself. After extraction, the ion beam is to be transported towards an accelerating structure in most cases. For lower intensities, this transport can be done without space charge compensation. However, if space charge is not negligible, the positive charge of the ion beam will attract electrons, which will compensate the space charge, at least partially. The final degree of Space Charge Compensation (SCC) will depend on different properties, like the ratio of generation rate of secondary particles and their loss rate, or the fact whether the ion beam is pulsed or continuous. In sections of the beam line, where the ion beam is drifting, a pure electrostatic plasma will develop, whereas in magnetic elements, these space charge compensating electrons become magnetized. The transport section will provide a series of different plasma conditions with different properties. Different measurement tools to investigate the degree of space charge compensation will be described, as well as computational methods for the simulation of ion beams with partial space charge compensation

Space charge limited avalanche growth in multigap resistive plate chambers

International Nuclear Information System (INIS)

Akindinov, A.N.; Kaidalov, A.B.; Kisselev, S.M.; Alici, A.; Basile, M.; Cifarelli, L.; Anselmo, F.; Antonioli, P.; Romeo, G. Cara; Cindolo, F.; Baek, Y.; Kim, D.H.; Cosenza, F.; Caro, A. De; Pasquale, S. De; Bartolomeo, A. Di; Girard, M. Fusco; Guida, M.; Hatzifotiadou, D.; Kim, D.W.; Laurenti, G.; Lee, K.; Lee, S.C.; Lioublev, E.; Luvisetto, M.L.; Margotti, A.; Martemiyanov, A.N.; Nania, R.; Noferini, F.; Otiougova, P.; Pierella, F.; Polozov, P.A.; Scapparone, E.; Scioli, G.; Sellitto, S.B.; Smirnitski, A.V.; Tchoumakov, M.M.; Valenti, G.; Vicinanza, D.; Voloshin, K.G.; Williams, M.C.S.; Zagreev, B.V.; Zampolli, C.; Zichichi, A.

2004-01-01

Abstract The ALICE TOF array will be built using the Multigap Resistive Plate Chamber(MRPC) configured as a double stack. Each stack contains 5 gas gaps with width of 250 μm. There has been an intense R and D effort to optimise this new detector to withstand the problems connected with the high level of radiation at the LHC. One clear outcome of the R and D is that the growth of the gas avalanche is strongly affected by space charge. The effect of the space charge is a decrease in the rate of change in gain with electric field; this allows more stable operation of this detector. We have measured the gain as a function of the electric field and also measured the ratio of the fast charge to the total charge produced in the gas gap. It is well established that RPCs built with 250 μm gas gap have a much superior performance than 2 mm gaps; we discuss and compare the performance of 250 μm gap MRPCs with 2 mm gap RPCs to show the importance of space-charge limitation of avalanche growth. (orig.)

Stasis, Charging the Space of Change

Directory of Open Access Journals (Sweden)

Sarah Riviere

2017-02-01

Full Text Available This article fossicks through the fragments of historical understandings of the word stasis in ancient Greece – where stasis, in its extreme state, involved conflictual hostilities between kindred parties, often termed ‘civil war’ today. Through a series of readings of ancient Greek texts on topics ranging from pathology to literature and politics, stasis is revealed as a powerfully charged state of located dynamic exchange that operates through a precise temporal and spatial performance. This article teases out relevant aspects of the state of stasis – its high levels of spatial engagement, its inevitable resolution into energetic productivity, its precise restraint, its demand for full participation, and its role in the integration of change – all of which were acknowledged as part of the enactment and resolution of a stasis at that time. The intention of this article is to resurrect a more nuanced understanding of the state of stasis that can enrich current concepts of the dynamic in architectural and urban discourse. This understanding of stasis also poses new questions for the future design of spaces that can accommodate charged kindred engagement: lively spaces where contest becomes opportunity, and located spaces of kindred understanding that promise productive reconciliation as the common aim of all the parties involved.

Space-charge effects of the proportional counters in a multiple-ionization chamber

International Nuclear Information System (INIS)

Mang, M.

1993-01-01

At the ALADIN spectrometer of the GSI in october 1991 for the first time the new multiple ionization chamber was applied, in the two anode planes of which are additional multiwire-proportional counters. The proportional counters are required in order to make the detection of light fragments (Z 4 gold projectiles per second by these positive space charges the homogeneous electric field of the MUSIC is disturbed. This effect is especially strong in the beam plane. As consequence of the space charge additionally electrons are focused on the proportional counter so that their amplitudes in dependence on the beam intensity increase up to the 2.5-fold. Furthermore the y coordinate is falsified, because the electrons are diverted to the medium plane. On the measurement of the x coordinate this diversion has with maximally 0.1% only a small influence. These space-charge effects can be qualitatively described by a schematic model, which assumes a stationary positive space charge. Additionally for the proportional counters, which are not in the beam plane, their resolution was determined. In these counters the space-charge effects are small, because essentially fewer particles are registrated than in the medium MWPC's. By this charges of fragments with Z<10 could be separated. The charge resolution amounted at lithium 0.8 charge units. The position resolution of the proportional counters in y direction was determined to less than 8 mm. The detection probability of the fragments amounts for lithium 90% and from boron all fragments are detected

Space Charge Effect in the Sheet and Solid Electron Beam

Science.gov (United States)

Song, Ho Young; Kim, Hyoung Suk; Ahn, Saeyoung

1998-11-01

We analyze the space charge effect of two different types of electron beam ; sheet and solid electron beam. Electron gun simulations are carried out using shadow and control grids for high and low perveance. Rectangular and cylindrical geometries are used for sheet and solid electron beam in planar and disk type cathode. The E-gun code is used to study the limiting current and space charge loading in each geometries.

One-carrier free space charge motion under applied voltage

Energy Technology Data Exchange (ETDEWEB)

de ALMEIDA, L E.C.; FERREIRA, G F.L. [SAO PAULO UNIV., SAO CARLOS (BRAZIL). INSTITUTO DE FISICA E QUIMICA

1975-12-01

It is shown how to transform the system of partial differential equations, describing the free one-carrier space charge motion in solid dielectrics under a given applied voltage and while the charge distribution touches only one of the electrodes, into a first order ordinary differential equation from whose solution all the interesting quantities may be easily derived. It was found that some charge distributions can display current reversal.

Charged fluid distribution in higher dimensional spheroidal space-time

Indian Academy of Sciences (India)

A general solution of Einstein field equations corresponding to a charged fluid distribution on the background of higher dimensional spheroidal space-time is obtained. The solution generates several known solutions for superdense star having spheroidal space-time geometry.

On Beam Matching and the Space-Charge Effect in protoDUNE-SP

CERN Document Server

Mandalia, Jesal Paresh

2017-01-01

In this project simulations using LArSoft have been analysed in particular looking at how the space-charge effect will affect the matching of particle tracks from the beam line monitor to the TPC and the TPC's performance measuring $\\frac{dE}{dx}$ in protoDUNE-SP. The analysis here provides some preliminary calibrations for protoDUNE-SP to account for the impact the space charge effect will have. Many areas of pion cross section analysis will be affected by the space charge effect so it is vital for a calibration to be developed.

Role of geometrical shape in like-charge attraction of DNA.

Science.gov (United States)

Kuron, Michael; Arnold, Axel

2015-03-01

While the phenomenon of like-charge attraction of DNA is clearly observed experimentally and in simulations, mean-field theories fail to predict it. Kornyshev et al. argued that like-charge attraction is due to DNA's helical geometry and hydration forces. Strong-coupling (SC) theory shows that attraction of like-charged rods is possible through ion correlations alone at large coupling parameters, usually by multivalent counterions. However for SC theory to be applicable, counterion-counterion correlations perpendicular to the DNA strands need to be sufficiently small, which is not a priori the case for DNA even with trivalent counterions. We study a system containing infinitely long DNA strands and trivalent counterions by computer simulations employing varying degrees of coarse-graining. Our results show that there is always attraction between the strands, but its magnitude is indeed highly dependent on the specific shape of the strand. While discreteness of the charge distribution has little influence on the attractive forces, the role of the helical charge distribution is considerable: charged rods maintain a finite distance in equilibrium, while helices collapse to close contact with a phase shift of π, in full agreement with SC predictions. The SC limit is applicable because counterions strongly bind to the charged sites of the helices, so that helix-counterion interactions dominate over counterion-counterion interactions. Thus DNA's helical geometry is not crucial for like-charge DNA attraction, but strongly enhances it, and electrostatic interactions in the strong-coupling limit are sufficient to explain this attraction.

High-order space charge effects using automatic differentiation

International Nuclear Information System (INIS)

Reusch, M.F.; Bruhwiler, D.L.; Computer Accelerator Physics Conference Williamsburg, Virginia 1996)

1997-01-01

The Northrop Grumman Topkark code has been upgraded to Fortran 90, making use of operator overloading, so the same code can be used to either track an array of particles or construct a Taylor map representation of the accelerator lattice. We review beam optics and beam dynamics simulations conducted with TOPKARK in the past and we present a new method for modeling space charge forces to high-order with automatic differentiation. This method generates an accurate, high-order, 6-D Taylor map of the phase space variable trajectories for a bunched, high-current beam. The spatial distribution is modeled as the product of a Taylor Series times a Gaussian. The variables in the argument of the Gaussian are normalized to the respective second moments of the distribution. This form allows for accurate representation of a wide range of realistic distributions, including any asymmetries, and allows for rapid calculation of the space charge fields with free space boundary conditions. An example problem is presented to illustrate our approach. copyright 1997 American Institute of Physics

Effect of the space-charge force on tracking at low energy

International Nuclear Information System (INIS)

Furman, M.A.

1987-01-01

The authors present tracking results for the SSC's Low Energy Booster at injection energy, including the effect of the space-charge force. The bunches are assumed to be gaussian with elliptical cross-section. Magnet errors and sextupoles are not included, but an RF cavity is. The authors compare the phase space with and without synchrotron oscillations, with and without space-charge. The effective emittance is not significantly altered. They also present results on tune shifts with amplitude

Pore structure and function of synthetic nanopores with fixed charges: tip shape and rectification properties

Energy Technology Data Exchange (ETDEWEB)

RamIrez, Patricio [Departament de Fisica Aplicada, Universitat Politecnica de Valencia, E-46022 Valencia (Spain); Apel, Pavel Yu [Flerov Laboratory of Nuclear Reactions, Joint Institute for Nuclear Research, Joliot-Curie street 6, 141980 Dubna (Russian Federation); Cervera, Javier; Mafe, Salvador [Departament de Fisica de la Terra i Termodinamica, Universitat de Valencia, E-46100 Burjassot (Spain)], E-mail: patraho@fis.upv.es

2008-08-06

We present a complete theoretical study of the relationship between the structure (tip shape and dimensions) and function (selectivity and rectification) of asymmetric nanopores on the basis of previous experimental studies. The theoretical model uses a continuum approach based on the Nernst-Planck equations. According to our results, the nanopore transport properties, such as current-voltage (I-V) characteristics, conductance, rectification ratio, and selectivity, are dictated mainly by the shape of the pore tip (we have distinguished bullet-like, conical, trumpet-like, and hybrid shapes) and the concentration of pore surface charges. As a consequence, the nanopore performance in practical applications will depend not only on the base and tip openings but also on the pore shape. In particular, we show that the pore opening dimensions estimated from the pore conductance can be very different, depending on the pore shape assumed. The results obtained can also be of practical relevance for the design of nanopores, nanopipettes, and nanoelectrodes, where the electrical interactions between the charges attached to the nanostructure and the mobile charges confined in the reduced volume of the inside solution dictate the device performance in practical applications. Because single tracks are the elementary building blocks for nanoporous membranes, the understanding and control of their individual properties should also be crucial in protein separation, water desalination, and bio-molecule detection using arrays of identical nanopores.

Pore structure and function of synthetic nanopores with fixed charges: tip shape and rectification properties

International Nuclear Information System (INIS)

RamIrez, Patricio; Apel, Pavel Yu; Cervera, Javier; Mafe, Salvador

2008-01-01

We present a complete theoretical study of the relationship between the structure (tip shape and dimensions) and function (selectivity and rectification) of asymmetric nanopores on the basis of previous experimental studies. The theoretical model uses a continuum approach based on the Nernst-Planck equations. According to our results, the nanopore transport properties, such as current-voltage (I-V) characteristics, conductance, rectification ratio, and selectivity, are dictated mainly by the shape of the pore tip (we have distinguished bullet-like, conical, trumpet-like, and hybrid shapes) and the concentration of pore surface charges. As a consequence, the nanopore performance in practical applications will depend not only on the base and tip openings but also on the pore shape. In particular, we show that the pore opening dimensions estimated from the pore conductance can be very different, depending on the pore shape assumed. The results obtained can also be of practical relevance for the design of nanopores, nanopipettes, and nanoelectrodes, where the electrical interactions between the charges attached to the nanostructure and the mobile charges confined in the reduced volume of the inside solution dictate the device performance in practical applications. Because single tracks are the elementary building blocks for nanoporous membranes, the understanding and control of their individual properties should also be crucial in protein separation, water desalination, and bio-molecule detection using arrays of identical nanopores

Pore structure and function of synthetic nanopores with fixed charges: tip shape and rectification properties.

Science.gov (United States)

Ramírez, Patricio; Apel, Pavel Yu; Cervera, Javier; Mafé, Salvador

2008-08-06

We present a complete theoretical study of the relationship between the structure (tip shape and dimensions) and function (selectivity and rectification) of asymmetric nanopores on the basis of previous experimental studies. The theoretical model uses a continuum approach based on the Nernst-Planck equations. According to our results, the nanopore transport properties, such as current-voltage (I-V) characteristics, conductance, rectification ratio, and selectivity, are dictated mainly by the shape of the pore tip (we have distinguished bullet-like, conical, trumpet-like, and hybrid shapes) and the concentration of pore surface charges. As a consequence, the nanopore performance in practical applications will depend not only on the base and tip openings but also on the pore shape. In particular, we show that the pore opening dimensions estimated from the pore conductance can be very different, depending on the pore shape assumed. The results obtained can also be of practical relevance for the design of nanopores, nanopipettes, and nanoelectrodes, where the electrical interactions between the charges attached to the nanostructure and the mobile charges confined in the reduced volume of the inside solution dictate the device performance in practical applications. Because single tracks are the elementary building blocks for nanoporous membranes, the understanding and control of their individual properties should also be crucial in protein separation, water desalination, and bio-molecule detection using arrays of identical nanopores.

The effects of electromagnetic space-charge fields in RF photocathode guns

International Nuclear Information System (INIS)

Park, C.S.; Hess, M.

2010-01-01

In high-brightness rf photocathode guns, the effects of space-charge are important for electron bunches with high bunch charge. In an effort to accurately simulate the effects of these space-charge fields without the presence of numerical grid dispersion, a Green's function based code called IRPSS (Indiana Rf Photocathode Source Simulator) was developed. In this paper, we show the results of numerical simulations of the Argonne Wakefield Accelerator photocathode gun using IRPSS, and compare them with the results of an electrostatic Green's function version of IRPSS.

Design of achromatic bending systems in the presence of space charge

International Nuclear Information System (INIS)

Jason, A.J.; Svaton, E.M.; Blind, B.; Heighway, E.A.

1987-01-01

The usual conditions for achromaticity of a dispersive system are shown to be inadequate when space-charge effects are included. Using a matrix formulation describing linear space-charge forces, we give generalized criteria necessary for a system to be achromatic. Additionally, these conditions are necessary for conservation of transverse emittances. An example of such a system is given

Design of achromatic bending systems in the presence of space charge

International Nuclear Information System (INIS)

Jason, A.J.; Svaton, E.M.; Blind, B.; Heighway, E.A.

1987-01-01

The usual conditions for achromaticity of a dispersive system are shown to be inadequate when space-charge effects are included. Using a matrix formulation describing linear space-charge forces, the authors give generalized criteria necessary for a system to be achromatic. Additionally, these conditions are necessary for conservation of transverse emittances. An example of such a system is given

Space-charge-limited currents: An E-infinity Cantorian approach

Czech Academy of Sciences Publication Activity Database

Zmeškal, O.; Nešpůrek, Stanislav; Weiter, M.

2007-01-01

Roč. 34, č. 2 (2007), s. 143-158 ISSN 0960-0779 R&D Projects: GA MPO FT-TA/036; GA AV ČR IAA100100622 Institutional research plan: CEZ:AV0Z40500505 Keywords : space charge * fractal * charge injection Subject RIV: CD - Macromolecular Chemistry Impact factor: 3.025, year: 2007

Exploring the design space of shape-changing objects

DEFF Research Database (Denmark)

Nørgaard, Mie; Merritt, Timothy Robert; Rasmussen, Majken

2013-01-01

In this paper we describe the outcomes from a design exercise in which eight groups of designers designed and built hardware sketches in the form of playful shape-changing prototypes, generatively working with Rasmussen et al's [31] eight unique types of shape change. Seeing that shape-changing i......In this paper we describe the outcomes from a design exercise in which eight groups of designers designed and built hardware sketches in the form of playful shape-changing prototypes, generatively working with Rasmussen et al's [31] eight unique types of shape change. Seeing that shape...... for the further expansion of the design space of shape changing interfaces relating to the perception and understanding of behaviour, causality and the mechanics involved in shape change events, which we call "Imagined Physics." This concept is described along with additional insights into the qualities of shape...

Space-charge effects in high-energy photoemission

Energy Technology Data Exchange (ETDEWEB)

Verna, Adriano, E-mail: adriano.verna@uniroma3.it [Dipartimento di Scienze, Università degli Studi Roma Tre, Via della Vasca Navale 84, I-00146 Roma (Italy); CNISM Unità di Roma Tre, Via della Vasca Navale 84, I-00146 Roma (Italy); Greco, Giorgia [Dipartimento di Scienze, Università degli Studi Roma Tre, Via della Vasca Navale 84, I-00146 Roma (Italy); Lollobrigida, Valerio [Dipartimento di Scienze, Università degli Studi Roma Tre, Via della Vasca Navale 84, I-00146 Roma (Italy); Scuola Dottorale in Matematica e Fisica, Università Roma Tre, Via della Vasca Navale 84, I-00146 Roma (Italy); Offi, Francesco; Stefani, Giovanni [Dipartimento di Scienze, Università degli Studi Roma Tre, Via della Vasca Navale 84, I-00146 Roma (Italy); CNISM Unità di Roma Tre, Via della Vasca Navale 84, I-00146 Roma (Italy)

2016-05-15

Highlights: • N-body simulations of interacting photoelectrons in hard X-ray experiments. • Secondary electrons have a pivotal role in determining the energy broadening. • Space charge has negligible effects on the photoelectron momentum distribution. • A simple model provides the characteristic time for energy-broadening mechanism. • The feasibility of time-resolved high-energy experiments with FELs is discussed. - Abstract: Pump-and-probe photoelectron spectroscopy (PES) with femtosecond pulsed sources opens new perspectives in the investigation of the ultrafast dynamics of physical and chemical processes at the surfaces and interfaces of solids. Nevertheless, for very intense photon pulses a large number of photoelectrons are simultaneously emitted and their mutual Coulomb repulsion is sufficiently strong to significantly modify their trajectory and kinetic energy. This phenomenon, referred as space-charge effect, determines a broadening and shift in energy for the typical PES structures and a dramatic loss of energy resolution. In this article we examine the effects of space charge in PES with a particular focus on time-resolved hard X-ray (∼10 keV) experiments. The trajectory of the electrons photoemitted from pure Cu in a hard X-ray PES experiment has been reproduced through N-body simulations and the broadening of the photoemission core-level peaks has been monitored as a function of various parameters (photons per pulse, linear dimension of the photon spot, photon energy). The energy broadening results directly proportional to the number N of electrons emitted per pulse (mainly represented by secondary electrons) and inversely proportional to the linear dimension a of the photon spot on the sample surface, in agreement with the literature data about ultraviolet and soft X-ray experiments. The evolution in time of the energy broadening during the flight of the photoelectrons is also studied. Despite its detrimental consequences on the energy

Analysis of beam envelope by transverse space charge effect

International Nuclear Information System (INIS)

Toyama, Shin'ichi

1997-09-01

It is important for high current accelerators to estimate the contribution of the space charge effect to keep the beam off its beak up. The application of an envelope equation is examined in previous report in which the beam is just coasting beam (non accelerating). The analysis of space charge effect is necessary for the comparison in coming accelerator test in PNC. In order to evaluate the beam behavior in high current, the beam dynamics and beam parameters which are input to the equation for the evaluation are developed and make it ready to estimate the beam transverse dynamics by the space charge. The estimate needs to have enough accuracy for advanced code calculation. After the preparation of the analytic expression of transverse motion, the non-linear differential equation of beam dynamics is solved by a numerical method on a personal computer. The beam envelope from the equation is estimated by means of the beam emittance, current and energy. The result from the analysis shows that the transverse beam broadening is scarecely small around the beam current value of PNC design. The contribution to the beam broadening of PNC linac comes from its beam emittance. The beam broadening in 100 MeV case is almost negligible in the view of transverse space charge effect. Therefore, the electron beam is stable up to 10 A order in PNC linac design. Of course, the problem for RF supply is out of consideration here. It is important to estimate other longitudinal effect such as beam bunch effect which is lasting unevaluated. (author)

Electric field and space-charge distribution in SI GaAs: effect of high-energy proton irradiation

CERN Document Server

Castaldini, A; Polenta, L; Canali, C; Nava, F

1999-01-01

The effect of irradiation on semi-insulating gallium arsenide Schottky diodes has been investigated by means of surface potential measurements and spectroscopic techniques. Before and after irradiation the electric field exhibits a Mott barrier-like distribution, and the box-shaped space charge modifies its distribution with irradiation. The increase in density or the generation of some traps changes the compensation ratio producing a deeper active region and a more homogeneous distribution of the electric field. The latter phenomenon is also observed by EBIC images of edge-mounted diodes.

The Influence of Pre-Conditioning on Space Charge Formation in LDPE

DEFF Research Database (Denmark)

Fleming, Robert J.; Henriksen, Mogens; Holbøll, Joachim T.

1996-01-01

In this paper we present space charge accumulation data for planar low density polyethylene samples subjected to 20 kV/mm dc fields at room temperature. The data were obtained using the laser-induced-pressure-pulse (LIPP) technique. Some of the samples were conditioned by holding them at 40oC in ......C in short-circuit at rotary pump pressure for 48 hr prior to measurement. Such conditioning had no consistent effect on the space charge. The extent of charge injection/extraction at the semicon electrodes appeared to vary considerably between samples....

Space Charge Mitigation With Longitudinally Hollow Bunches

CERN Multimedia

Oeftiger, Adrian; Rumolo, Giovanni

2016-01-01

Hollow longitudinal phase space distributions have a flat profile and hence reduce the impact of transverse space charge. Dipolar parametric excitation with the phase loop feedback systems provides such hollow distributions under reproducible conditions. We present a procedure to create hollow bunches during the acceleration ramp of CERN’s PS Booster machine with minimal changes to the operational cycle. The improvements during the injection plateau of the downstream Proton Synchrotron are assessed in comparison to standard parabolic bunches.

Protein structure and ionic selectivity in calcium channels: selectivity filter size, not shape, matters.

Science.gov (United States)

Malasics, Attila; Gillespie, Dirk; Nonner, Wolfgang; Henderson, Douglas; Eisenberg, Bob; Boda, Dezso

2009-12-01

Calcium channels have highly charged selectivity filters (4 COO(-) groups) that attract cations in to balance this charge and minimize free energy, forcing the cations (Na(+) and Ca(2+)) to compete for space in the filter. A reduced model was developed to better understand the mechanism of ion selectivity in calcium channels. The charge/space competition (CSC) mechanism implies that Ca(2+) is more efficient in balancing the charge of the filter because it provides twice the charge as Na(+) while occupying the same space. The CSC mechanism further implies that the main determinant of Ca(2+) versus Na(+) selectivity is the density of charged particles in the selectivity filter, i.e., the volume of the filter (after fixing the number of charged groups in the filter). In this paper we test this hypothesis by changing filter length and/or radius (shape) of the cylindrical selectivity filter of our reduced model. We show that varying volume and shape together has substantially stronger effects than varying shape alone with volume fixed. Our simulations show the importance of depletion zones of ions in determining channel conductance calculated with the integrated Nernst-Planck equation. We show that confining the protein side chains with soft or hard walls does not influence selectivity.

Space-charge effects on bunching of electrons in the CEBAF injector

International Nuclear Information System (INIS)

Liu, H.

1997-01-01

The main injector for the 4 GeV CEBAF accelerator at Thomas Jefferson national accelerator facility was designed to deliver simultaneously three CW electron beams for nuclear physics research. The maximum design current for a single beam from the injector is 100 μA, or 0.2 pC per microbunch at a repetition rate of 499 MHz. It was found through computer simulation that space charge even at a subpicocoulomb level can spoil the bunching of electrons significantly, and some unexpected phenomena observed experimentally could be explained accordingly. This problem arises because of the low-momentum tilt allowed for bunching to preserve low-momentum spread. In this paper, we analyze in detail the space-charge effects on bunching of electrons with the CEBAF injector as an example. Conditions for effective matching of longitudinal phase space in the presence of space charge are discussed. (orig.)

Charge conjugation and internal space time symmetries

International Nuclear Information System (INIS)

Pavsic, M.; Recami, E.

1982-01-01

The relativistic framework in which fundamental particles are regarded as extended objects is adopted. Then it is shown than the geometrical operation which reflects the internal space time particle is equivalent to the operation C which inverts the sign of all its additive charges

Exploring the Design Space of Shape-Changing Objects

DEFF Research Database (Denmark)

Merritt, Timothy; Petersen, Marianne Graves; Nørgaard, Mie

2015-01-01

In this paper we describe the outcomes from a design exercise in which eight groups of designers designed and built hardware sketches in the form of playful shape- changing prototypes, generatively working with Rasmussen et al’s [31] eight unique types of shape change. Seeing that shape-changing ......In this paper we describe the outcomes from a design exercise in which eight groups of designers designed and built hardware sketches in the form of playful shape- changing prototypes, generatively working with Rasmussen et al’s [31] eight unique types of shape change. Seeing that shape...... for the further expansion of the design space of shape changing interfaces relating to the perception and understanding of behaviour, causality and the mechanics involved in shape change events, which we call “Imagined Physics.” This concept is described along with additional insights into the qualities of shape...

Space charge-limited emission studies using Coulomb's Law

OpenAIRE

Carr, Christopher G.

2004-01-01

Approved for Public Release; Distribution is Unlimited Child and Langmuir introduced a solution to space charge limited emission in an infinite area planar diode. The solution follows from starting with Poisson's equation, and requires solving a non-linear differential equation. This approach can also be applied to cylindrical and spherical geometries, but only for one-dimensional cases. By approaching the problem from Coulomb's law and applying the effect of an assumed charge distribution...

Effect of the space charge layer on pre-transition corrosion rate of Zr alloys

International Nuclear Information System (INIS)

Nanikawa, S.; Etoh, Y.

1998-01-01

The pre- and post-transition oxide films formed in steam at 673 K were investigated by an AC impedance method. The results showed that the space charge layer was present in the pre-transition oxide film and it was absent in the post-transition oxide film. The oxidation kinetics was simulated by oxygen diffusion in the space charge layer. Cubic or one-fourth power law was explained by the effect of the space charge layer. Supposing that the space charge layer formed the potential difference through the oxide film by 0.7 V, calculated oxidation kinetics agreed with the experimental one before transition. This potential difference corresponded to the measured value by AC impedance method within the experimental error. Shadow effect could be explained by this simulation supposing the disappearance of the space charge layer due to the formation of a negative electric field by β-rays. (author)

Assessment of space proton radiation-induced charge transfer inefficiency in the CCD204 for the Euclid space observatory

International Nuclear Information System (INIS)

Gow, J P D; Murray, N J; Holland, A D; Hall, D J; Cropper, M; Burt, D; Hopkinson, G; Duvet, L

2012-01-01

Euclid is a medium class European Space Agency mission candidate for launch in 2019 with a primary goal to study the dark universe using the weak lensing and baryonic acoustic oscillations techniques. Weak lensing depends on accurate shape measurements of distant galaxies. Therefore it is beneficial that the effects of radiation-induced charge transfer inefficiency (CTI) in the Euclid CCDs over the course of the 5 year mission at L2 are understood. This will allow, through experimental analysis and modelling techniques, the effects of radiation induced CTI on shape to be decoupled from those of mass inhomogeneities along the line-of-sight. This paper discusses a selection of work from the study that has been undertaken using the e2v CCD204 as part of the initial proton radiation damage assessment for Euclid. The experimental arrangement and procedure are described followed by the results obtained, thereby allowing recommendations to be made on the CCD operating temperature, to provide an insight into CTI effects using an optical background, to assess the benefits of using charge injection on CTI recovery and the effect of the use of two different methods of serial clocking on serial CTI. This work will form the basis of a comparison with a p-channel CCD204 fabricated using the same mask set as the n-channel equivalent. A custom CCD has been designed, based on this work and discussions between e2v technologies plc. and the Euclid consortium, and designated the CCD273.

Negative space charge effects in photon-enhanced thermionic emission solar converters

International Nuclear Information System (INIS)

Segev, G.; Weisman, D.; Rosenwaks, Y.; Kribus, A.

2015-01-01

In thermionic energy converters, electrons in the gap between electrodes form a negative space charge and inhibit the emission of additional electrons, causing a significant reduction in conversion efficiency. However, in Photon Enhanced Thermionic Emission (PETE) solar energy converters, electrons that are reflected by the electric field in the gap return to the cathode with energy above the conduction band minimum. These electrons first occupy the conduction band from which they can be reemitted. This form of electron recycling makes PETE converters less susceptible to negative space charge loss. While the negative space charge effect was studied extensively in thermionic converters, modeling its effect in PETE converters does not account for important issues such as this form of electron recycling, nor the cathode thermal energy balance. Here, we investigate the space charge effect in PETE solar converters accounting for electron recycling, with full coupling of the cathode and gap models, and addressing conservation of both electric and thermal energy. The analysis shows that the negative space charge loss is lower than previously reported, allowing somewhat larger gaps compared to previous predictions. For a converter with a specific gap, there is an optimal solar flux concentration. The optimal solar flux concentration, the cathode temperature, and the efficiency all increase with smaller gaps. For example, for a gap of 3 μm the maximum efficiency is 38% and the optimal flux concentration is 628, while for a gap of 5 μm the maximum efficiency is 31% and optimal flux concentration is 163

Adaptive electron beam shaping using a photoemission gun and spatial light modulator

Science.gov (United States)

Maxson, Jared; Lee, Hyeri; Bartnik, Adam C.; Kiefer, Jacob; Bazarov, Ivan

2015-02-01

The need for precisely defined beam shapes in photoelectron sources has been well established. In this paper, we use a spatial light modulator and simple shaping algorithm to create arbitrary, detailed transverse laser shapes with high fidelity. We transmit this shaped laser to the photocathode of a high voltage dc gun. Using beam currents where space charge is negligible, and using an imaging solenoid and fluorescent viewscreen, we show that the resultant beam shape preserves these detailed features with similar fidelity. Next, instead of transmitting a shaped laser profile, we use an active feedback on the unshaped electron beam image to create equally accurate and detailed shapes. We demonstrate that this electron beam feedback has the added advantage of correcting for electron optical aberrations, yielding shapes without skew. The method may serve to provide precisely defined electron beams for low current target experiments, space-charge dominated beam commissioning, as well as for online adaptive correction of photocathode quantum efficiency degradation.

Adaptive electron beam shaping using a photoemission gun and spatial light modulator

Directory of Open Access Journals (Sweden)

Jared Maxson

2015-02-01

Full Text Available The need for precisely defined beam shapes in photoelectron sources has been well established. In this paper, we use a spatial light modulator and simple shaping algorithm to create arbitrary, detailed transverse laser shapes with high fidelity. We transmit this shaped laser to the photocathode of a high voltage dc gun. Using beam currents where space charge is negligible, and using an imaging solenoid and fluorescent viewscreen, we show that the resultant beam shape preserves these detailed features with similar fidelity. Next, instead of transmitting a shaped laser profile, we use an active feedback on the unshaped electron beam image to create equally accurate and detailed shapes. We demonstrate that this electron beam feedback has the added advantage of correcting for electron optical aberrations, yielding shapes without skew. The method may serve to provide precisely defined electron beams for low current target experiments, space-charge dominated beam commissioning, as well as for online adaptive correction of photocathode quantum efficiency degradation.

Space-charge-mediated anomalous ferroelectric switching in P(VDF-TrEE) polymer films

KAUST Repository

Hu, Weijin; Wang, Zhihong; Du, Yuanmin; Zhang, Xixiang; Wu, Tao

2014-01-01

We report on the switching dynamics of P(VDF-TrEE) copolymer devices and the realization of additional substable ferroelectric states via modulation of the coupling between polarizations and space charges. The space-charge-limited current

The longitudinal space charge problem in the high current linear proton accelerators

International Nuclear Information System (INIS)

Lustfeld, H.

1984-01-01

In a linear proton accelerator peak currents of 200 mA lead to high space charge densities and the resultant space charge forces reduce the effective focussing considerably. In particular the longitudinal focussing is affected. A new concept based on linear theory is proposed that restricts the influence of the space charge forces on the longitudinal focussing by increasing a, the mean transverse bunch radius, as a proportional(βγ)sup(3/8). This concept is compared with other concepts for the Alvarez (1 MeV - 100 MeV) and for the high energy part (100 MeV - 1100 MeV) of the SNQ linear accelerator. (orig.)

Cancellation of the centrifugal space-charge force

International Nuclear Information System (INIS)

Lee, E.P.

1990-01-01

The transverse dynamics of high-energy electrons confined in curved geometry are examined, including the effects of space-charge-induced fields. Attention is restricted to the centrifugal-space-charge force, which is the result of noncancellation of beam-induced transverse electric and magnetic fields in the curved geometry. This force is shown to be nearly cancelled in the evaluation of the horizontal tune and chromaticity by another, often overlooked term in the equation of motion. The additional term is the consequence of oscillations of the kinetic energy, which accompany betatron oscillations in the beam-induced electric potential. In curved geometry this term is of first order in the amplitude of the radial oscillation. A highly simplified system model is employed so that physical effects appear in as clear a form as possible. We assume azimuthal and median plane symmetry, static fields, and ultrarelativistic particle velocity (1/γ 2 ->0). (author) 9 refs

Space-charge-mediated anomalous ferroelectric switching in P(VDF-TrEE) polymer films

KAUST Repository

Hu, Weijin

2014-11-12

We report on the switching dynamics of P(VDF-TrEE) copolymer devices and the realization of additional substable ferroelectric states via modulation of the coupling between polarizations and space charges. The space-charge-limited current is revealed to be the dominant leakage mechanism in such organic ferroelectric devices, and electrostatic interactions due to space charges lead to the emergence of anomalous ferroelectric loops. The reliable control of ferroelectric switching in P(VDF-TrEE) copolymers opens doors toward engineering advanced organic memories with tailored switching characteristics.

A modified space charge routine for high intensity bunched beams

International Nuclear Information System (INIS)

Lapostolle, P.; Lombardi, A.M.; Tanke, E.; Valero, S.; Garnett, R.W.; Wangler, T.P.

1996-01-01

A new routine and a computer code (DYNAC) for the calculation of space charge densities in a new generation of linear accelerators for various industrial applications is presented. The new beam dynamics method used in this code, employs a set of quasi-Liouvillian equations, allowing beam dynamics computations in long and complex structures for electrons, as well as protons and ions. With this new beam dynamics method, the coordinates of particles are known at any position in the accelerating elements, allowing multistep space charge calculations. (K.A.)

CrossRef Space-charge effects in Penning ion traps

CERN Document Server

Porobić, T; Breitenfeldt, M; Couratin, C; Finlay, P; Knecht, A; Fabian, X; Friedag, P; Fléchard, X; Liénard, E; Ban, G; Zákoucký, D; Soti, G; Van Gorp, S; Weinheimer, Ch; Wursten, E; Severijns, N

2015-01-01

The influence of space-charge on ion cyclotron resonances and magnetron eigenfrequency in a gas-filled Penning ion trap has been investigated. Off-line measurements with View the MathML source using the cooling trap of the WITCH retardation spectrometer-based setup at ISOLDE/CERN were performed. Experimental ion cyclotron resonances were compared with ab initio Coulomb simulations and found to be in agreement. As an important systematic effect of the WITCH experiment, the magnetron eigenfrequency of the ion cloud was studied under increasing space-charge conditions. Finally, the helium buffer gas pressure in the Penning trap was determined by comparing experimental cooling rates with simulations.

Effect of ion compensation of the beam space charge on gyrotron operation

Energy Technology Data Exchange (ETDEWEB)

Fokin, A. P.; Glyavin, M. Yu. [Institute of Applied Physics, Russian Academy of Sciences, Nizhny Novgorod 603950 (Russian Federation); Nusinovich, G. S. [Institute for Research in Electronics and Applied Physics, University of Maryland, College Park, Maryland 20742-3511 (United States)

2015-04-15

In gyrotrons, the coherent radiation of electromagnetic waves takes place when the cyclotron resonance condition between the wave frequency and the electron cyclotron frequency or its harmonic holds. The voltage depression caused by the beam space charge field changes the relativistic cyclotron frequency and, hence, can play an important role in the beam-wave interaction process. In long pulse and continuous-wave regimes, the beam space charge field can be partially compensated by the ions, which appear due to the beam impact ionization of neutral molecules of residual gases in the interaction space. In the present paper, the role of this ion compensation of the beam space charge on the interaction efficiency is analyzed. We also analyze the effect of the electron velocity spread on the limiting currents and discuss some effects restricting the ion-to-beam electron density ratio in the saturation stage. It is shown that the effect of the ion compensation on the voltage depression caused by the beam space charge field can cause significant changes in the efficiency of gyrotron operation and, in some cases, even result in the break of oscillations.

Theory and Simulation of the Physics of Space Charge Dominated Beams

International Nuclear Information System (INIS)

Haber, Irving

2002-01-01

This report describes modeling of intense electron and ion beams in the space charge dominated regime. Space charge collective modes play an important role in the transport of intense beams over long distances. These modes were first observed in particle-in-cell simulations. The work presented here is closely tied to the University of Maryland Electron Ring (UMER) experiment and has application to accelerators for heavy ion beam fusion

Space charge models and PATH

International Nuclear Information System (INIS)

Wald, H.B.

1990-01-01

The 'PATH' codes are used to design magnetic optics subsystems for neutral particle beam systems. They include a 2-1/2D and three 3-D space charge models, two of which have recently been added. This paper describes the 3-D models and reports on preliminary benchmark studies in which these models are checked for stability as the cloud size is varied and for consistency with each other. Differences between the models are investigated and the computer time requirements for running these models are established

Space Charge Correction on Emittance Measurement of Low Energy Electron Beams

Energy Technology Data Exchange (ETDEWEB)

Treado, Colleen J.; /Massachusetts U., Amherst

2012-09-07

The goal of any particle accelerator is to optimize the transport of a charged particle beam along a set path by confining the beam to a small region close to the design trajectory and directing it accurately along the beamline. To do so in the simplest fashion, accelerators use a system of magnets that exert approximately linear electromagnetic forces on the charged beam. These electromagnets bend the beam along the desired path, in the case of bending magnets, and constrain the beam to the desired area through alternating focusing and defocusing effects, in the case of quadrupole magnets. We can model the transport of such a beam through transfer matrices representing the actions of the various beamline elements. However, space charge effects, produced from self electric fields within the beam, defocus the beam and must be accounted for in the calculation of beam emittance. We present below the preliminary results of a MATLAB code built to model the transport of a charged particle beam through an accelerator and measure the emittance under the influence of space charge effects. We demonstrate the method of correctly calculating the emittance of a beam under space charge effects using a least square fit to determine the initial properties of the beam given the beam size measured at a specific point after transport.

Beam halo formation from space-charge dominated beams in uniform focusing channels

International Nuclear Information System (INIS)

O'Connell, J.S.; Wangler, T.P.; Mills, R.S.; Crandall, K.R.

1993-01-01

In space-charge dominated beams the nonlinear space-charge forces produce a filamentation pattern, which results in a 2-component beam consisting of an inner core and an outer halo. The halo is very prominent in mismatched beams, and the potential for accelerator activation is of concern for a next generation of cw, high-power proton linacs that could be applied for intense neutron generators to process nuclear materials. We present new results about beam halo and the evolution of space-charge dominated beams from multiparticle simulation of initial laminar beams in a uniform linear focusing channel, and from a model consisting of single particle interactions with a uniform-density beam core. We study the energy gain from particle interactions with the space-charge field of the core, and we identify the resonant characteristic of this interaction as the basic cause of the separation of the beam into the two components. We identify three different particle-trajectory types, and we suggest that one of these types may lead to continuous halo growth, even after the halo is removed by collimators

Space Charge Effects for the ERL Prototype Injector Line at Daresbury Laboratory

CERN Document Server

Muratori, Bruno; Owen, Hywel; de Loos, Marieke; van der Geer, Bas

2005-01-01

Daresbury Laboratory is currently building an Energy Recovery Linac Prototype (ERLP) that will operate at a beam energy of 35 MeV. In this paper we examine the space charge effects on the beam dynamics in the ERLP injector line. A Gaussian particle distribution is tracked with GPT (General Particle Tracer) through the injection line to the main linac to calculate the effect of 3Dspace charge in the dipoles. The nominal beam energy in the injection line is 8.3 MeV and the bunch charge 80 pC. The effects of space charge on the transverse and longitudinal emittance are studied for various electron beam parameter settings.

Effect of paraelectrode processes on contraction of space charge in periodic-pulse lasers

Science.gov (United States)

Arytyunyan, R. V.; Baranov, V. Yu.; Borisov, V. M.; Vinokhodov, A. Yu.; Kiryukhin, Yu. B.

1986-05-01

A characteristic feature of periodic-pulse electric-discharge CO2-lasers and excimer lasers is contraction of the space charge as the pulse repetition rate increases. The emission energy per pulse decreases as a consequence, with the average laser power first ceasing to increase linearly beyond a certain corner repetition rate and then decreasing beyond a certain critical repetition rate. A study of this phenomenon was made, for the purpose of separating the effect of paracathode processes from the effect of gas dynamics and then evaluating the effect of the former alone. Paraelectrode perturbations were simulated by focusing the radiation from the an XeCl-laser on the cathode surface in an atmosphere of nonabsorbing gases. Laser pulses of up to approximately 0.5 J energy and of approximately 50 ns duration were focused within a spot of 1 mm(2) area on a cathode inside a discharge chamber, with the power density of incident radiation regulated by means of an attenuator. A space charge within a volume of 2.5x4.5x9 cm(3) was generated between this specially shaped cathode and a mesh anode with an approximately 50% optical transmission coefficient. The space charge in helium and in neon was photographed, and the time lag of a discharge pulse behind a contracting laser pulse was measured as a function of the laser pulse energy for these two gases, as well as for a He+C12 gas mixture. The general trend was found to be the same in each case, the time lag increasing with increasing energy first at a slower rate up to a critical energy level and then faster. It has been established that plasma does not build up on the cathode before the laser pulse energy reaches 30 mJ (for a 3 mm(2) surface area), while plasma glow begins as the laser pulse energy reaches 150 mJ. A contracted channel begins to form within the laser-cathode interaction space, with an attendant fast increase of the time lag owing to evaporation of the cathode metal.

Experiments on ion space-charge neutralization with pulsed electron beams

Energy Technology Data Exchange (ETDEWEB)

Herleb, U; Riege, H [CERN LHC-Division, Geneva (Switzerland)

1997-12-31

The method of space-charge neutralization of heavy ion beams with electron beam pulses generated with electron guns incorporating ferroelectric cathodes was investigated experimentally. Several experiments are described, the results of which prove that the intensity of selected ion beam parts with defined charge states generated in a laser ion source can be increased by an order of magnitude. For elevated charge states the intensity amplification is more significant and may reach a factor of 4 for highly charged ions from an Al target. (author). 7 figs., 3 -refs.

Three-dimensional space charge calculation method

International Nuclear Information System (INIS)

Lysenko, W.P.; Wadlinger, E.A.

1981-01-01

A method is presented for calculating space-charge forces suitable for use in a particle tracing code. Poisson's equation is solved in three dimensions with boundary conditions specified on an arbitrary surface by using a weighted residual method. Using a discrete particle distribution as our source input, examples are shown of off-axis, bunched beams of noncircular crosssection in radio-frequency quadrupole (RFQ) and drift-tube linac geometries

Quantum theory of space charge limited current in solids

Energy Technology Data Exchange (ETDEWEB)

González, Gabriel, E-mail: gabriel.gonzalez@uaslp.mx [Cátedras Conacyt, Universidad Autónoma de San Luis Potosí, San Luis Potosí 78000, Mexico and Coordinación para la Innovación y la Aplicación de la Ciencia y la Tecnología, Universidad Autónoma de San Luis Potosí, San Luis Potosí 78000 (Mexico)

2015-02-28

We present a quantum model of space charge limited current transport inside trap-free solids with planar geometry in the mean field approximation. We use a simple transformation which allows us to find the exact analytical solution for the steady state current case. We use our approach to find a Mott-Gurney like behavior and the mobility for single charge carriers in the quantum regime in solids.

Space charge effect in the spiral inflector

International Nuclear Information System (INIS)

Toprek, Dragan

2000-01-01

This paper presents the analytical and numerical theory of the space charge effects in the beam in the spiral inflector. It considers a simplified model of a 'straight' cylindrical beam by using a uniform particle distribution. Numerical results represented in this paper are obtained by using a modified version of the program CASINO

Space-charge limits in linear accelerators

International Nuclear Information System (INIS)

Wangler, T.P.

1980-12-01

This report presents equations that allow an approximate evaluation of the limiting beam current for a large class of radio-frequency linear accelerators, which use quadrupole strong focusing. Included are the Alvarez, the Wideroe, and the radio-frequency quadrupole linacs. The limiting-current formulas are presented for both the longitudinal and the transverse degrees of freedom by assuming that the average space-charge force in the beam bunch arises from a uniformly distributed charge within an azimuthally symmetric three-dimensional ellipsoid. The Mathieu equation is obtained as an approximate, but general, form for the transverse equation of motion. The smooth-approximation method is used to obtain a solution and an expression for the transverse current limit. The form of the current-limit formulas for different linac constraints is discussed

Space-charge effect in electron time-of-flight analyzer for high-energy photoemission spectroscopy

International Nuclear Information System (INIS)

Greco, G.; Verna, A.; Offi, F.; Stefani, G.

2016-01-01

Highlights: • Two methods for the simulation of space-charge effect in time-resolved PES. • Reliability and advantages in the use of the SIMION"® software. • Simulation of the space-charge effect in an electron TOF analyzer. • Feasibility of a TOF analyzer in time-resolved high-energy PES experiments at FEL. - Abstract: The space-charge effect, due to the instantaneous emission of many electrons after the absorption of a single photons pulse, causes distortion in the photoelectron energy spectrum. Two calculation methods have been applied to simulate the expansion during a free flight of clouds of mono- and bi-energetic electrons generated by a high energy pulse of light and their results have been compared. The accuracy of a widely used tool, such as SIMION"®, in predicting the energy distortion caused by the space-charge has been tested and the reliability of its results is verified. Finally we used SIMION"® to take into account the space-charge effects in the simulation of simple photoemission experiments with a time-of-flight analyzer.

Improving the beam quality of rf guns by correction of rf and space-charge effects

International Nuclear Information System (INIS)

Serafini, L.

1992-01-01

In this paper we describe two possible strategies to attain ultra-low emittance electron beam generation by laser-driven RF guns. The first one is based on the exploitation of multi-mode resonant cavities to neutralize the emittance degradation induced by RF effects. Accelerating cigar-like (long and thin) electron bunches in multi-mode operated RF guns the space charge induced emittance is strongly decreased at the same time: high charged bunches, as typically requested by future TeV e - e + colliders, can be delivered by the gun at a quite low transverse emittance and good behaviour in the longitudinal phase space, so that they can be magnetically compressed to reach higher peak currents. The second strategy consists in using disk-like electron bunches, produced by very short laser pulses illuminating the photocathode. By means of an analytical study a new regime has been found, where the normalized transverse emittance scales like the inverse of the peak current, provided that the laser pulse intensity distribution is properly shaped in the transverse direction. Preliminary numerical simulations confirm the analytical predictions and show that the minimum emittance achievable is set up, in this new regime, by the wake-field interaction between the bunch and the cathode metallic wall

The influence of oxidation on space charge formation in gamma-irradiated low-density polyethylene

CERN Document Server

Chen, G; Xie, H K; Banford, H M; Davies, A E

2003-01-01

The research presented in this paper investigates the role of oxidation in the formation of space charge in gamma-irradiated low-density polyethylene after being electrically stressed under dc voltage. Polyethylene plaques both with and without antioxidant were irradiated up to 500 kGy using a sup 6 sup 0 Co gamma source and space charge distributions were measured using the piezoelectric induced pressure wave propagation method. It has been found that a large amount of positive charge evolved adjacent to the cathode in the sample without antioxidant and was clearly associated with oxidation of the surface. The amount of charge formed for a given applied stress increased with the dose absorbed by the material. A model has been proposed to explain the formation of space charge and its profile. The charge decay after the removal of the external applied stress is dominated by a process being controlled by the cathode interfacial stress (charge injection) rather than a conventional RC circuit model. On the other ...

Space Charge Effects and Advanced Modelling for CERN Low Energy Machines

CERN Document Server

AUTHOR|(CDS)2088716; Rumolo, Giovanni

The strong space charge regime of future operation of CERN’s circular particle accelerators is investigated and mitigation strategies are developed in the framework of the present thesis. The intensity upgrade of the injector chain of Large Hadron Collider (LHC) prepares the particle accelerators to meet the requirements of the High-Luminosity LHC project. Producing the specified characteristics of the future LHC beams imperatively relies on injecting brighter bunches into the Proton Synchrotron Booster (PSB), the downstream Proton Synchrotron (PS) and eventually the Super Proton Synchrotron (SPS). The increased brightness, i.e. bunch intensity per transverse emittance, entails stronger beam self-fields which can lead to harmful interaction with betatron resonances. Possible beam emittance growth and losses as a consequence thereof threaten to degrade the beam brightness. These space charge effects are partly mitigated by the upgrade of the PSB and PS injection energies. Nevertheless, the space charge tune ...

The effect of space charge force on beams extracted from ECR ion sources

International Nuclear Information System (INIS)

Xie, Z.Q.

1989-01-01

A new 3 dimensional ray tracing code BEAM-3D, with a simple model to calculate the space charge force of multiple ion species, is under development and serves as a theoretical tool to study the ECRIS beam formation. Excellent agreement between the BEAM-3D calculations and beam profile and emittance measurements of the total extracted helium 1+ beam from the RTECR ion source was obtained when a low degree of beam neutralization was assumed in the calculations. The experimental evidence indicates that the positive space charge effects dominate the early RTECR ion source beam formation and beamline optics matching process. A review of important beam characteristics is made, including a conceptual model for the space charge beam blow up. Better beam transport through the RTECR beamline analysis magnet has resulted after an extraction geometry modification in which the space charge force was more correctly matched. This work involved the development of an online beam characteristic measuring apparatus which will also be described

Space charge build-up in XLPE-cable with temperature gradient

DEFF Research Database (Denmark)

Holbøll, Joachim; Henriksen, Mogens; Hjerrild, Jesper

2000-01-01

and temperatures were applied in the 20 - 80°C range with gradients across the insulation of up to 15°C. In this paper, the observed charge phenomena in the bulk and at the interfaces are related to the external conditions, in particular to the temperature gradient. The measured space charge distributions...

'V' shaped predens space

International Nuclear Information System (INIS)

Bohrer, S.P.; Klein, A.; Martin, W.

1985-01-01

''V'' shaped widening of the predens space (PDS) in flexion can be a worrisome finding in traume patients, possibly representing injury to the transverse ligament. These patients may also show widening of the C-1/C-2 interspinous distance. We think this appearance is usually due to increased flexion mobility at the atlantoaxial level with developmental elongation or laxity of the cranial end of the transverse ligament and/or the posterior ligamentous complex. Tearing of only the cranial end of the transverse ligament must be extremely rare, if it occurs at all; there is no reported proven case. Tearing of only posterior ligaments seems possible and should be evaluated clinically. (orig.)

Simple shape space for 3D face registration

Science.gov (United States)

Košir, Andrej; Perkon, Igor; Bracun, Drago; Tasic, Jurij; Mozina, Janez

2009-09-01

Three dimensional (3D) face recognition is a topic getting increasing interest in biometric applications. In our research framework we developed a laser scanner that provides 3D cloud information and texture data. In a user scenario with cooperative subjects with indoor light conditions, we address three problems of 3D face biometrics: the face registration, the formulation of a shape space together with a special designed gradient algorithm and the impact of initial approximation to the convergence of a registration algorithm. By defining the face registration as a problem of aligning a 3D data cloud with a predefined reference template, we solve the registration problem with a second order gradient algorithm working on a shape space designed for reducing the computational complexity of the method.

Space-charge effects in Penning ion traps

Czech Academy of Sciences Publication Activity Database

Porobic, T.; Beck, M.; Breitenfeldt, M.; Couratin, C.; Finlay, P.; Knecht, A.; Fabian, X.; Friedag, P.; Flechard, X.; Lienard, E.; Ban, G.; Zákoucký, Dalibor; Soti, G.; Van Gorp, S.; Weinheimer, C.; Wursten, E.; Severijns, N.

2015-01-01

Roč. 785, JUN (2015), s. 153-162 ISSN 0168-9002 R&D Projects: GA MŠk LA08015; GA MŠk(CZ) LG13031 Institutional support: RVO:61389005 Keywords : Penning trap * space-charge * magnetron motion * ion trapping * buffer gas cooling * ion cyclotron resonance Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 1.200, year: 2015

Alternating phase focussing including space charge

International Nuclear Information System (INIS)

Cheng, W.H.; Gluckstern, R.L.

1992-01-01

Longitudinal stability can be obtained in a non-relativistic drift tube accelerator by traversing each gap as the rf accelerating field rises. However, the rising accelerating field leads to a transverse defocusing force which is usually overcome by magnetic focussing inside the drift tubes. The radio frequency quadrupole is one way of providing simultaneous longitudinal and transverse focusing without the use of magnets. One can also avoid the use of magnets by traversing alternate gaps between drift tubes as the field is rising and falling, thus providing an alternation of focussing and defocusing forces in both the longitudinal and transverse directions. The stable longitudinal phase space area is quite small, but recent efforts suggest that alternating phase focussing (APF) may permit low velocity acceleration of currents in the 100-300 ma range. This paper presents a study of the parameter space and a test of crude analytic predictions by adapting the code PARMILA, which includes space charge, to APF. 6 refs., 3 figs

Event-shape-engineering study of charge separation in heavy-ion collisions

Science.gov (United States)

Wen, Fufang; Bryon, Jacob; Wen, Liwen; Wang, Gang

2018-01-01

Recent measurements of charge-dependent azimuthal correlations in high-energy heavy-ion collisions have indicated charge-separation signals perpendicular to the reaction plane, and have been related to the chiral magnetic effect (CME). However, the correlation signal is contaminated with the background caused by the collective motion (flow) of the collision system, and an effective approach is needed to remove the flow background from the correlation. We present a method study with simplified Monte Carlo simulations and a multi-phase transport model, and develop a scheme to reveal the true CME signal via event-shape engineering with the flow vector of the particles of interest. Supported by a grant (DE-FG02-88ER40424) from U.S. Department of Energy, Office of Nuclear Physics

Study of electric field distorted by space charges under positive lightning impulse voltage

Science.gov (United States)

Wang, Zezhong; Geng, Yinan

2018-03-01

Actually, many insulation problems are related to electric fields. And measuring electric fields is an important research topic of high-voltage engineering. In particular, the electric field distortion caused by space charge is the basis of streamer theory, and thus quantitatively measuring the Poisson electric field caused by space charge is significant to researching the mechanism of air gap discharge. In this paper, we used our photoelectric integrated sensor to measure the electric field distribution in a 1-m rod-plane gap under positive lightning impulse voltage. To verify the reliability of this quantitative measurement, we compared the measured results with calculated results from a numerical simulation. The electric-field time domain waveforms on the axis of the 1-m rod-plane out of the space charge zone were measured with various electrodes. The Poisson electric fields generated by space charge were separated from the Laplace electric field generated by applied voltages, and the amplitudes and variations were measured for various applied voltages and at various locations. This work also supplies the feasible basis for directly measuring strong electric field under high voltage.

Ignition-and-Growth Modeling of NASA Standard Detonator and a Linear Shaped Charge

Science.gov (United States)

Oguz, Sirri

2010-01-01

The main objective of this study is to quantitatively investigate the ignition and shock sensitivity of NASA Standard Detonator (NSD) and the shock wave propagation of a linear shaped charge (LSC) after being shocked by NSD flyer plate. This combined explosive train was modeled as a coupled Arbitrary Lagrangian-Eulerian (ALE) model with LS-DYNA hydro code. An ignition-and-growth (I&G) reactive model based on unreacted and reacted Jones-Wilkins-Lee (JWL) equations of state was used to simulate the shock initiation. Various NSD-to-LSC stand-off distances were analyzed to calculate the shock initiation (or failure to initiate) and detonation wave propagation along the shaped charge. Simulation results were verified by experimental data which included VISAR tests for NSD flyer plate velocity measurement and an aluminum target severance test for LSC performance verification. Parameters used for the analysis were obtained from various published data or by using CHEETAH thermo-chemical code.

Generation of initial kinetic distributions for simulation of long-pulse charged particle beams with high space-charge intensity

Directory of Open Access Journals (Sweden)

Steven M. Lund

2009-11-01

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

History of the Shaped Charge Effect: The First 100 Years

Science.gov (United States)

1990-03-22

patent, wave shapers, follow-through, U.S. 1949 39 6.5-in. ATAR HEAT rocket, U.S. NOTS, 1950 (schematic) 40 Test of 15-in. long standoff shaped charge...Swiss chemist Frederick Schoenbein in 1845, and nitroglycerin, derived by Ascanio Sobrero, professor of Chemistry at the University of Turin, Italy, in...totally new warhead and fuze system and delivery of the first 1000 rounds to Korea in less than 20 days! The 6.5-Inch ATAR (Code Name "RAM") The 6.5

Surface Layer Fluorination-Modulated Space Charge Behaviors in HVDC Cable Accessory

Directory of Open Access Journals (Sweden)

Jin Li

2018-05-01

Full Text Available Space charges tend to accumulate on the surface and at the interface of ethylene–propylene–diene terpolymer (EPDM, serving as high voltage direct current (HVDC cable accessory insulation, which likely induces electrical field distortion and dielectric breakdown. Direct fluorination is an effective method to modify the surface characteristics of the EPDM without altering the bulk properties too much. In this paper, the surface morphology, hydrophobic properties, relative permittivity, and DC conductivity of the EPDM before and after fluorination treatment were tested. Furthermore, the surface and interface charge behaviors in the HVDC cable accessory were investigated by the pulsed electroacoustic (PEA method, and explained from the point of view of trap distribution. The results show that fluorination helps the EPDM polymer obtain lower surface energy and relative permittivity, which is beneficial to the interface match in composite insulation systems. The lowest degree of space charge accumulation occurs in EPDM with 30 min of fluorination. After analyzing the results of the 3D potentials and the density of states (DOS behaviors in EPDM before and after fluorination, it can be found that fluorination treatment introduces shallower electron traps, and the special electrostatic potential after fluorination can significantly suppress the space charge accumulation at the interface in the HVDC cable accessory.

Longitudinal and transverse space charge limitations on transport of maximum power beams

International Nuclear Information System (INIS)

Khoe, T.K.; Martin, R.L.

1977-01-01

The maximum transportable beam power is a critical issue in selecting the most favorable approach to generating ignition pulses for inertial fusion with high energy accelerators. Maschke and Courant have put forward expressions for the limits on transport power for quadrupole and solenoidal channels. Included in a more general way is the self consistent effect of space charge defocusing on the power limit. The results show that no limits on transmitted power exist in principal. In general, quadrupole transport magnets appear superior to solenoids except for transport of very low energy and highly charged particles. Longitudinal space charge effects are very significant for transport of intense beams

Simulation of space charge effects and transition crossing in the Fermilab Booster

International Nuclear Information System (INIS)

Lucas, P.; MacLachlan, J.

1987-03-01

The longitudinal phase space program ESME, modified for space charge and wall impedance effects, has been used to simulate transition crossing in the Fermilab Booster. The simulations yield results in reasonable quantitative agreement with measured parameters. They further indicate that a transition jump scheme currently under construction will significantly reduce emittance growth, while attempts to alter machine impedance are less obviously beneficial. In addition to presenting results, this paper points out a serious difficulty, related to statistical fluctuations, in the space charge calculation. False indications of emittance growth can appear if care is not taken to minimize this problem

Space charge and beam stability issues of the Fermilab proton driver in Phase I

Energy Technology Data Exchange (ETDEWEB)

K. Y. Ng

2001-08-24

Issues concerning beam stability of the proposed Fermilab Proton Driver are studied in its Phase I. Although the betatron tune shifts are dominated by space charge, these shifts are less than 0.25 and will therefore not drive the symmetric and antisymmetric modes of the beam envelope into instability. The longitudinal space charge force is large and inductive inserts may be needed to compensate for the distortion of the rf potential. Although the longitudinal impedance is space charge dominated, it will not drive any microwave instability, unless the real part of the impedance coming from the inductive inserts and wall resistivity of the beam tube are large enough. The design of the beam tube is therefore very important in order to limit the flow of eddy current and keep wall resistivity low. The transverse impedance is also space charge dominated. With the Proton Driver operated at an imaginary transition gamma, however, Landau damping will never be canceled and beam stability can be maintained with negative chromaticities.

Simulation of a cascaded longitudinal space charge amplifier for coherent radiation generation

Energy Technology Data Exchange (ETDEWEB)

Halavanau, A., E-mail: aliaksei.halavanau@gmail.com [Department of Physics and Northern Illinois, Center for Accelerator & Detector Development, Northern Illinois University, DeKalb, IL 60115 (United States); Accelerator Physics Center, Fermi National Accelerator Laboratory, Batavia, IL 60510 (United States); Piot, P. [Department of Physics and Northern Illinois, Center for Accelerator & Detector Development, Northern Illinois University, DeKalb, IL 60115 (United States); Accelerator Physics Center, Fermi National Accelerator Laboratory, Batavia, IL 60510 (United States)

2016-05-21

Longitudinal space charge (LSC) effects are generally considered as harmful in free-electron lasers as they can seed unfavorable energy modulations that can result in density modulations with associated emittance dilution. This “micro-bunching instabilities” is naturally broadband and could possibly support the generation of coherent radiation over a broad region of the spectrum. Therefore there has been an increasing interest in devising accelerator beam lines capable of controlling LSC induced density modulations. In the present paper we refine these previous investigations by combining a grid-less space charge algorithm with the popular particle-tracking program ELEGANT. This high-fidelity model of the space charge is used to benchmark conventional LSC models. We finally employ the developed model to investigate the performance of a cascaded LSC amplifier using beam parameters comparable to the ones achievable at Fermilab Accelerator Science & Technology (FAST) facility currently under commissioning at Fermilab.

Adaptive matching of the iota ring linear optics for space charge compensation

Energy Technology Data Exchange (ETDEWEB)

Romanov, A. [Fermilab; Bruhwiler, D. L. [RadiaSoft, Boulder; Cook, N. [RadiaSoft, Boulder; Hall, C. [RadiaSoft, Boulder

2016-10-09

Many present and future accelerators must operate with high intensity beams when distortions induced by space charge forces are among major limiting factors. Betatron tune depression of above approximately 0.1 per cell leads to significant distortions of linear optics. Many aspects of machine operation depend on proper relations between lattice functions and phase advances, and can be i proved with proper treatment of space charge effects. We implement an adaptive algorithm for linear lattice re matching with full account of space charge in the linear approximation for the case of Fermilab’s IOTA ring. The method is based on a search for initial second moments that give closed solution and, at the same predefined set of goals for emittances, beta functions, dispersions and phase advances at and between points of interest. Iterative singular value decomposition based technique is used to search for optimum by varying wide array of model parameters

Shaping space programme as a tool for educating youth about architecture

Science.gov (United States)

Marczak, Piotr

2017-10-01

The Polish Architectural Policy’s vision of a systematic promotion of spatial culture has made its way into the national curriculum for 2009 - 2016 designed for various stages of child and teenager education. The objective of this effort was to furnish a basis for a system of architectural education which allows teaching society to be more conscious in their decisions as to spatial order with the effect of improving the quality of our living space. Educating individuals to engage consciously in activities related to the protection of space and transformations taking place within that space requires an understanding of basic issues connected with space, the nature of space and the interrelations of various elements which form it. The “Shaping space” programme under the patronage of the Chamber of Polish Architects is one of the tools dedicated to students of lower and higher secondary schools, designed to assist teachers as architectural educators. The aim of this paper is to present the results of a survey related to the implementation of the programme in Lower Secondary School 3 in Malbork in the years 2013-2016. The programme involved observation of students (of grades 1 to 3) in architecture-oriented classes, assistance for the teacher in the class rooms well as an evaluation of the usefulness of educational materials. A number of problems became evident during the implementation of the “Shaping space” programme which is now available in book form. The size of the book is large enough to discourage any potential readers. The subject matter of the book is not suitable for the intended age group (age: 13-16). Another issue was the teacher’s suitability to conduct this type of class. Class observation in grades 1-3 of the lower secondary school and discussions with teachers in charge of that programme served as a basis for developing our own tools and materials in the form of multimedia presentations, templates and lesson scenarios designed to convey

Generalized space-charge limited current and virtual cathode behaviors in one-dimensional drift space

International Nuclear Information System (INIS)

Yang, Zhanfeng; Liu, Guozhi; Shao, Hao; Chen, Changhua; Sun, Jun

2013-01-01

This paper reports the space-charge limited current (SLC) and virtual cathode behaviors in one-dimensional grounded drift space. A simple general analytical solution and an approximate solution for the planar diode are given. Through a semi-analytical method, a general solution for SLC in one-dimensional drift space is obtained. The behaviors of virtual cathode in the drift space, including dominant frequency, electron transit time, position, and transmitted current, are yielded analytically. The relationship between the frequency of the virtual cathode oscillation and the injected current presented may explain previously reported numerical works. Results are significant in facilitating estimations and further analytical studies

The Role of Shape on Electronic Structure and Charge Transport in Faceted PbSe Nanocrystals

KAUST Repository

Kaushik, Ananth P.

2014-03-25

We have determined the effect of shape on the charge transport characteristics of nanocrystals. Our study looked at the explicit determination of the electronic properties of faceted nanocrystals that essentially probe the limit of current computational reach, i.e., nanocrystals from 1.53 to 2.1 nm in diameter. These nanocrystals, which resemble PbSe systems, are either bare or covered in short ligands. They also differ in shape, octahedral vs cube-octahedral, and in superlattice symmetry (fcc vs bcc). We have provided insights on electron and hole coupling along different facets and overall charge mobility in bcc and fcc superlattices. We have determined that the relative areas of (100) to (111) facets, and facet atom types are important factors governing the optimization of charge transport. The calculated electronic density of states shows no role of -SCH3 - ligands on states near the band gap. Electron coupling between nanocrystals is significantly higher than that of hole coupling; thiol ligands lower the ratio between electron and hole couplings. Stronger coupling exists between smaller nanocrystals. © 2014 American Chemical Society.

Geodesics of electrically and magnetically charged test particles in the Reissner-Nordstroem space-time: Analytical solutions

International Nuclear Information System (INIS)

Grunau, Saskia; Kagramanova, Valeria

2011-01-01

We present the full set of analytical solutions of the geodesic equations of charged test particles in the Reissner-Nordstroem space-time in terms of the Weierstrass weierp, σ, and ζ elliptic functions. Based on the study of the polynomials in the θ and r equations, we characterize the motion of test particles and discuss their properties. The motion of charged test particles in the Reissner-Nordstroem space-time is compared with the motion of neutral test particles in the field of a gravitomagnetic monopole. Electrically or magnetically charged particles in the Reissner-Nordstroem space-time with magnetic or electric charges, respectively, move on cones similar to neutral test particles in the Taub-NUT space-times.

Study of static properties of magnetron-type space charges; Etude des proprietes statiques des charges d'espace du type magnetron

Energy Technology Data Exchange (ETDEWEB)

Delcroix, Jean-Loup

1953-05-30

This research thesis reports an in-depth analysis of physical properties of static regimes to address the issue of space charges. This theoretical study of the Hull magnetron is followed by the description of experiments on the Hull magnetron which highlight transitions between the different regimes. Then, another theoretical approach aims at generalising the magnetron theory, based on other types of magnetron theory (general equations of magnetron-type space charges, inverted Hull magnetron theory, circular field magnetron theory)

Measurement of charged-particle event shape variables in $\\sqrt{s}$ = 7 TeV proton-proton interactions with the ATLAS detector

CERN Document Server

Aad, Georges; Abbott, Brad; Abdallah, Jalal; Abdel Khalek, Samah; Abdelalim, Ahmed Ali; Abdinov, Ovsat; Aben, Rosemarie; Abi, Babak; Abolins, Maris; AbouZeid, Ossama; Abramowicz, Halina; Abreu, Henso; Acerbi, Emilio; Acharya, Bobby Samir; Adamczyk, Leszek; Adams, David; Addy, Tetteh; Adelman, Jahred; Adomeit, Stefanie; Adragna, Paolo; Adye, Tim; Aefsky, Scott; Aguilar-Saavedra, Juan Antonio; Agustoni, Marco; Aharrouche, Mohamed; Ahlen, Steven; Ahles, Florian; Ahmad, Ashfaq; Ahsan, Mahsana; Aielli, Giulio; Akdogan, Taylan; Åkesson, Torsten Paul Ake; Akimoto, Ginga; Akimov, Andrei; Alam, Mohammad; Alam, Muhammad Aftab; Albert, Justin; Albrand, Solveig; Aleksa, Martin; Aleksandrov, Igor; Alessandria, Franco; Alexa, Calin; Alexander, Gideon; Alexandre, Gauthier; Alexopoulos, Theodoros; Alhroob, Muhammad; Aliev, Malik; Alimonti, Gianluca; Alison, John; Allbrooke, Benedict; Allport, Phillip; Allwood-Spiers, Sarah; Almond, John; Aloisio, Alberto; Alon, Raz; Alonso, Alejandro; Alonso, Francisco; Alvarez Gonzalez, Barbara; Alviggi, Mariagrazia; Amako, Katsuya; Amelung, Christoph; Ammosov, Vladimir; Amorim, Antonio; Amram, Nir; Anastopoulos, Christos; Ancu, Lucian Stefan; Andari, Nansi; Andeen, Timothy; Anders, Christoph Falk; Anders, Gabriel; Anderson, Kelby; Andreazza, Attilio; Andrei, George Victor; Anduaga, Xabier; Anger, Philipp; Angerami, Aaron; Anghinolfi, Francis; Anisenkov, Alexey; Anjos, Nuno; Annovi, Alberto; Antonaki, Ariadni; Antonelli, Mario; Antonov, Alexey; Antos, Jaroslav; Anulli, Fabio; Aoki, Masato; Aoun, Sahar; Aperio Bella, Ludovica; Apolle, Rudi; Arabidze, Giorgi; Aracena, Ignacio; Arai, Yasuo; Arce, Ayana; Arfaoui, Samir; Arguin, Jean-Francois; Arik, Engin; Arik, Metin; Armbruster, Aaron James; Arnaez, Olivier; Arnal, Vanessa; Arnault, Christian; Artamonov, Andrei; Artoni, Giacomo; Arutinov, David; Asai, Shoji; Asfandiyarov, Ruslan; Ask, Stefan; Åsman, Barbro; Asquith, Lily; Assamagan, Ketevi; Astbury, Alan; Atkinson, Markus; Aubert, Bernard; Auge, Etienne; Augsten, Kamil; Aurousseau, Mathieu; Avolio, Giuseppe; Avramidou, Rachel Maria; Axen, David; Azuelos, Georges; Azuma, Yuya; Baak, Max; Baccaglioni, Giuseppe; Bacci, Cesare; Bach, Andre; Bachacou, Henri; Bachas, Konstantinos; Backes, Moritz; Backhaus, Malte; Badescu, Elisabeta; Bagnaia, Paolo; Bahinipati, Seema; Bai, Yu; Bailey, David; Bain, Travis; Baines, John; Baker, Oliver Keith; Baker, Mark; Baker, Sarah; Banas, Elzbieta; Banerjee, Piyali; Banerjee, Swagato; Banfi, Danilo; Bangert, Andrea Michelle; Bansal, Vikas; Bansil, Hardeep Singh; Barak, Liron; Baranov, Sergei; Barbaro Galtieri, Angela; Barber, Tom; Barberio, Elisabetta Luigia; Barberis, Dario; Barbero, Marlon; Bardin, Dmitri; Barillari, Teresa; Barisonzi, Marcello; Barklow, Timothy; Barlow, Nick; Barnett, Bruce; Barnett, Michael; Baroncelli, Antonio; Barone, Gaetano; Barr, Alan; Barreiro, Fernando; Barreiro Guimarães da Costa, João; Barrillon, Pierre; Bartoldus, Rainer; Barton, Adam Edward; Bartsch, Valeria; Basye, Austin; Bates, Richard; Batkova, Lucia; Batley, Richard; Battaglia, Andreas; Battistin, Michele; Bauer, Florian; Bawa, Harinder Singh; Beale, Steven; Beau, Tristan; Beauchemin, Pierre-Hugues; Beccherle, Roberto; Bechtle, Philip; Beck, Hans Peter; Becker, Anne Kathrin; Becker, Sebastian; Beckingham, Matthew; Becks, Karl-Heinz; Beddall, Andrew; Beddall, Ayda; Bedikian, Sourpouhi; Bednyakov, Vadim; Bee, Christopher; Beemster, Lars; Begel, Michael; Behar Harpaz, Silvia; Beimforde, Michael; Belanger-Champagne, Camille; Bell, Paul; Bell, William; Bella, Gideon; Bellagamba, Lorenzo; Bellina, Francesco; Bellomo, Massimiliano; Belloni, Alberto; Beloborodova, Olga; Belotskiy, Konstantin; Beltramello, Olga; Benary, Odette; Benchekroun, Driss; Bendtz, Katarina; Benekos, Nektarios; Benhammou, Yan; Benhar Noccioli, Eleonora; Benitez Garcia, Jorge-Armando; Benjamin, Douglas; Benoit, Mathieu; Bensinger, James; Benslama, Kamal; Bentvelsen, Stan; Berge, David; Bergeaas Kuutmann, Elin; Berger, Nicolas; Berghaus, Frank; Berglund, Elina; Beringer, Jürg; Bernat, Pauline; Bernhard, Ralf; Bernius, Catrin; Berry, Tracey; Bertella, Claudia; Bertin, Antonio; Bertolucci, Federico; Besana, Maria Ilaria; Besjes, Geert-Jan; Besson, Nathalie; Bethke, Siegfried; Bhimji, Wahid; Bianchi, Riccardo-Maria; Bianco, Michele; Biebel, Otmar; Bieniek, Stephen Paul; Bierwagen, Katharina; Biesiada, Jed; Biglietti, Michela; Bilokon, Halina; Bindi, Marcello; Binet, Sebastien; Bingul, Ahmet; Bini, Cesare; Biscarat, Catherine; Black, Kevin; Blair, Robert; Blanchard, Jean-Baptiste; Blanchot, Georges; Blazek, Tomas; Blocker, Craig; Blocki, Jacek; Blondel, Alain; Blum, Walter; Blumenschein, Ulrike; Bobbink, Gerjan; Bobrovnikov, Victor; Bocchetta, Simona Serena; Bocci, Andrea; Boddy, Christopher Richard; Boehler, Michael; Boek, Jennifer; Boelaert, Nele; Bogaerts, Joannes Andreas; Bogdanchikov, Alexander; Bogouch, Andrei; Bohm, Christian; Bohm, Jan; Boisvert, Veronique; Bold, Tomasz; Boldea, Venera; Bolnet, Nayanka Myriam; Bomben, Marco; Bona, Marcella; Boonekamp, Maarten; Booth, Chris; Bordoni, Stefania; Borer, Claudia; Borisov, Anatoly; Borissov, Guennadi; Borjanovic, Iris; Borri, Marcello; Borroni, Sara; Bortolotto, Valerio; Bos, Kors; Boscherini, Davide; Bosman, Martine; Boterenbrood, Hendrik; Bouchami, Jihene; Boudreau, Joseph; Bouhova-Thacker, Evelina Vassileva; Boumediene, Djamel Eddine; Bourdarios, Claire; Bousson, Nicolas; Boveia, Antonio; Boyd, James; Boyko, Igor; Bozovic-Jelisavcic, Ivanka; Bracinik, Juraj; Branchini, Paolo; Brandt, Andrew; Brandt, Gerhard; Brandt, Oleg; Bratzler, Uwe; Brau, Benjamin; Brau, James; Braun, Helmut; Brazzale, Simone Federico; Brelier, Bertrand; Bremer, Johan; Brendlinger, Kurt; Brenner, Richard; Bressler, Shikma; Britton, Dave; Brochu, Frederic; Brock, Ian; Brock, Raymond; Broggi, Francesco; Bromberg, Carl; Bronner, Johanna; Brooijmans, Gustaaf; Brooks, Timothy; Brooks, William; Brown, Gareth; Brown, Heather; Bruckman de Renstrom, Pawel; Bruncko, Dusan; Bruneliere, Renaud; Brunet, Sylvie; Bruni, Alessia; Bruni, Graziano; Bruschi, Marco; Buanes, Trygve; Buat, Quentin; Bucci, Francesca; Buchanan, James; Buchholz, Peter; Buckingham, Ryan; Buckley, Andrew; Buda, Stelian Ioan; Budagov, Ioulian; Budick, Burton; Büscher, Volker; Bugge, Lars; Bulekov, Oleg; Bundock, Aaron Colin; Bunse, Moritz; Buran, Torleiv; Burckhart, Helfried; Burdin, Sergey; Burgess, Thomas; Burke, Stephen; Busato, Emmanuel; Bussey, Peter; Buszello, Claus-Peter; Butler, Bart; Butler, John; Buttar, Craig; Butterworth, Jonathan; Buttinger, William; Cabrera Urbán, Susana; Caforio, Davide; Cakir, Orhan; Calafiura, Paolo; Calderini, Giovanni; Calfayan, Philippe; Calkins, Robert; Caloba, Luiz; Caloi, Rita; Calvet, David; Calvet, Samuel; Camacho Toro, Reina; Camarri, Paolo; Cameron, David; Caminada, Lea Michaela; Caminal Armadans, Roger; Campana, Simone; Campanelli, Mario; Canale, Vincenzo; Canelli, Florencia; Canepa, Anadi; Cantero, Josu; Cantrill, Robert; Capasso, Luciano; Capeans Garrido, Maria Del Mar; Caprini, Irinel; Caprini, Mihai; Capriotti, Daniele; Capua, Marcella; Caputo, Regina; Cardarelli, Roberto; Carli, Tancredi; Carlino, Gianpaolo; Carminati, Leonardo; Caron, Bryan; Caron, Sascha; Carquin, Edson; Carrillo Montoya, German D; Carter, Antony; Carter, Janet; Carvalho, João; Casadei, Diego; Casado, Maria Pilar; Cascella, Michele; Caso, Carlo; Castaneda Hernandez, Alfredo Martin; Castaneda-Miranda, Elizabeth; Castillo Gimenez, Victoria; Castro, Nuno Filipe; Cataldi, Gabriella; Catastini, Pierluigi; Catinaccio, Andrea; Catmore, James; Cattai, Ariella; Cattani, Giordano; Caughron, Seth; Cavaliere, Viviana; Cavalleri, Pietro; Cavalli, Donatella; Cavalli-Sforza, Matteo; Cavasinni, Vincenzo; Ceradini, Filippo; Santiago Cerqueira, Augusto; Cerri, Alessandro; Cerrito, Lucio; Cerutti, Fabio; Cetin, Serkant Ali; Chafaq, Aziz; Chakraborty, Dhiman; Chalupkova, Ina; Chan, Kevin; Chang, Philip; Chapleau, Bertrand; Chapman, John Derek; Chapman, John Wehrley; Chareyre, Eve; Charlton, Dave; Chavda, Vikash; Chavez Barajas, Carlos Alberto; Cheatham, Susan; Chekanov, Sergei; Chekulaev, Sergey; Chelkov, Gueorgui; Chelstowska, Magda Anna; Chen, Chunhui; Chen, Hucheng; Chen, Shenjian; Chen, Xin; Chen, Yujiao; Cheplakov, Alexander; Cherkaoui El Moursli, Rajaa; Chernyatin, Valeriy; Cheu, Elliott; Cheung, Sing-Leung; Chevalier, Laurent; Chiefari, Giovanni; Chikovani, Leila; Childers, John Taylor; Chilingarov, Alexandre; Chiodini, Gabriele; Chisholm, Andrew; Chislett, Rebecca Thalatta; Chitan, Adrian; Chizhov, Mihail; Choudalakis, Georgios; Chouridou, Sofia; Christidi, Illectra-Athanasia; Christov, Asen; Chromek-Burckhart, Doris; Chu, Ming-Lee; Chudoba, Jiri; Ciapetti, Guido; Ciftci, Abbas Kenan; Ciftci, Rena; Cinca, Diane; Cindro, Vladimir; Ciocca, Claudia; Ciocio, Alessandra; Cirilli, Manuela; Cirkovic, Predrag; Citterio, Mauro; Ciubancan, Mihai; Clark, Allan G; Clark, Philip James; Clarke, Robert; Cleland, Bill; Clemens, Jean-Claude; Clement, Benoit; Clement, Christophe; Coadou, Yann; Cobal, Marina; Coccaro, Andrea; Cochran, James H; Cogan, Joshua Godfrey; Coggeshall, James; Cogneras, Eric; Colas, Jacques; Cole, Stephen; Colijn, Auke-Pieter; Collins, Neil; Collins-Tooth, Christopher; Collot, Johann; Colombo, Tommaso; Colon, German; Conde Muiño, Patricia; Coniavitis, Elias; Conidi, Maria Chiara; Consonni, Sofia Maria; Consorti, Valerio; Constantinescu, Serban; Conta, Claudio; Conti, Geraldine; Conventi, Francesco; Cooke, Mark; Cooper, Ben; Cooper-Sarkar, Amanda; Copic, Katherine; Cornelissen, Thijs; Corradi, Massimo; Corriveau, Francois; Cortes-Gonzalez, Arely; Cortiana, Giorgio; Costa, Giuseppe; Costa, María José; Costanzo, Davide; Côté, David; Courneyea, Lorraine; Cowan, Glen; Cowden, Christopher; Cox, Brian; Cranmer, Kyle; Crescioli, Francesco; Cristinziani, Markus; Crosetti, Giovanni; Crépé-Renaudin, Sabine; Cuciuc, Constantin-Mihai; Cuenca Almenar, Cristóbal; Cuhadar Donszelmann, Tulay; Curatolo, Maria; Curtis, Chris; Cuthbert, Cameron; Cwetanski, Peter; Czirr, Hendrik; Czodrowski, Patrick; Czyczula, Zofia; D'Auria, Saverio; D'Onofrio, Monica; D'Orazio, Alessia; Da Cunha Sargedas De Sousa, Mario Jose; Da Via, Cinzia; Dabrowski, Wladyslaw; Dafinca, Alexandru; Dai, Tiesheng; Dallapiccola, Carlo; Dam, Mogens; Dameri, Mauro; Damiani, Daniel; Danielsson, Hans Olof; Dao, Valerio; Darbo, Giovanni; Darlea, Georgiana Lavinia; Dassoulas, James; Davey, Will; Davidek, Tomas; Davidson, Nadia; Davidson, Ruth; Davies, Eleanor; Davies, Merlin; Davignon, Olivier; Davison, Adam; Davygora, Yuriy; Dawe, Edmund; Dawson, Ian; Daya-Ishmukhametova, Rozmin; De, Kaushik; de Asmundis, Riccardo; De Castro, Stefano; De Cecco, Sandro; de Graat, Julien; De Groot, Nicolo; de Jong, Paul; De La Taille, Christophe; De la Torre, Hector; De Lorenzi, Francesco; de Mora, Lee; De Nooij, Lucie; De Pedis, Daniele; De Salvo, Alessandro; De Sanctis, Umberto; De Santo, Antonella; De Vivie De Regie, Jean-Baptiste; De Zorzi, Guido; Dearnaley, William James; Debbe, Ramiro; Debenedetti, Chiara; Dechenaux, Benjamin; Dedovich, Dmitri; Degenhardt, James; Del Papa, Carlo; Del Peso, Jose; Del Prete, Tarcisio; Delemontex, Thomas; Deliyergiyev, Maksym; Dell'Acqua, Andrea; Dell'Asta, Lidia; Della Pietra, Massimo; della Volpe, Domenico; Delmastro, Marco; Delsart, Pierre-Antoine; Deluca, Carolina; Demers, Sarah; Demichev, Mikhail; Demirkoz, Bilge; Deng, Jianrong; Denisov, Sergey; Derendarz, Dominik; Derkaoui, Jamal Eddine; Derue, Frederic; Dervan, Paul; Desch, Klaus Kurt; Devetak, Erik; Deviveiros, Pier-Olivier; Dewhurst, Alastair; DeWilde, Burton; Dhaliwal, Saminder; Dhullipudi, Ramasudhakar; Di Ciaccio, Anna; Di Ciaccio, Lucia; Di Girolamo, Alessandro; Di Girolamo, Beniamino; Di Luise, Silvestro; Di Mattia, Alessandro; Di Micco, Biagio; Di Nardo, Roberto; Di Simone, Andrea; Di Sipio, Riccardo; Diaz, Marco Aurelio; Diehl, Edward; Dietrich, Janet; Dietzsch, Thorsten; Diglio, Sara; Dindar Yagci, Kamile; Dingfelder, Jochen; Dinut, Florin; Dionisi, Carlo; Dita, Petre; Dita, Sanda; Dittus, Fridolin; Djama, Fares; Djobava, Tamar; Barros do Vale, Maria Aline; Do Valle Wemans, André; Doan, Thi Kieu Oanh; Dobbs, Matt; Dobinson, Robert; Dobos, Daniel; Dobson, Ellie; Dodd, Jeremy; Doglioni, Caterina; Doherty, Tom; Doi, Yoshikuni; Dolejsi, Jiri; Dolenc, Irena; Dolezal, Zdenek; Dolgoshein, Boris; Dohmae, Takeshi; Donadelli, Marisilvia; Donini, Julien; Dopke, Jens; Doria, Alessandra; Dos Anjos, Andre; Dotti, Andrea; Dova, Maria-Teresa; Doxiadis, Alexander; Doyle, Tony; Dris, Manolis; Dubbert, Jörg; Dube, Sourabh; Duchovni, Ehud; Duckeck, Guenter; Duda, Dominik; Dudarev, Alexey; Dudziak, Fanny; Dührssen, Michael; Duerdoth, Ian; Duflot, Laurent; Dufour, Marc-Andre; Duguid, Liam; Dunford, Monica; Duran Yildiz, Hatice; Duxfield, Robert; Dwuznik, Michal; Dydak, Friedrich; Düren, Michael; Ebke, Johannes; Eckweiler, Sebastian; Edmonds, Keith; Edson, William; Edwards, Clive; Edwards, Nicholas Charles; Ehrenfeld, Wolfgang; Eifert, Till; Eigen, Gerald; Einsweiler, Kevin; Eisenhandler, Eric; Ekelof, Tord; El Kacimi, Mohamed; Ellert, Mattias; Elles, Sabine; Ellinghaus, Frank; Ellis, Katherine; Ellis, Nicolas; Elmsheuser, Johannes; Elsing, Markus; Emeliyanov, Dmitry; Engelmann, Roderich; Engl, Albert; Epp, Brigitte; Erdmann, Johannes; Ereditato, Antonio; Eriksson, Daniel; Ernst, Jesse; Ernst, Michael; Ernwein, Jean; Errede, Deborah; Errede, Steven; Ertel, Eugen; Escalier, Marc; Esch, Hendrik; Escobar, Carlos; Espinal Curull, Xavier; Esposito, Bellisario; Etienne, Francois; Etienvre, Anne-Isabelle; Etzion, Erez; Evangelakou, Despoina; Evans, Hal; Fabbri, Laura; Fabre, Caroline; Fakhrutdinov, Rinat; Falciano, Speranza; Fang, Yaquan; Fanti, Marcello; Farbin, Amir; Farilla, Addolorata; Farley, Jason; Farooque, Trisha; Farrell, Steven; Farrington, Sinead; Farthouat, Philippe; Fassi, Farida; Fassnacht, Patrick; Fassouliotis, Dimitrios; Fatholahzadeh, Baharak; Favareto, Andrea; Fayard, Louis; Fazio, Salvatore; Febbraro, Renato; Federic, Pavol; Fedin, Oleg; Fedorko, Wojciech; Fehling-Kaschek, Mirjam; Feligioni, Lorenzo; Fellmann, Denis; Feng, Cunfeng; Feng, Eric; Fenyuk, Alexander; Ferencei, Jozef; Fernando, Waruna; Ferrag, Samir; Ferrando, James; Ferrara, Valentina; Ferrari, Arnaud; Ferrari, Pamela; Ferrari, Roberto; Ferreira de Lima, Danilo Enoque; Ferrer, Antonio; Ferrere, Didier; Ferretti, Claudio; Ferretto Parodi, Andrea; Fiascaris, Maria; Fiedler, Frank; Filipčič, Andrej; Filthaut, Frank; Fincke-Keeler, Margret; Fiolhais, Miguel; Fiorini, Luca; Firan, Ana; Fischer, Gordon; Fisher, Matthew; Flechl, Martin; Fleck, Ivor; Fleckner, Johanna; Fleischmann, Philipp; Fleischmann, Sebastian; Flick, Tobias; Floderus, Anders; Flores Castillo, Luis; Flowerdew, Michael; Fonseca Martin, Teresa; Formica, Andrea; Forti, Alessandra; Fortin, Dominique; Fournier, Daniel; Fox, Harald; Francavilla, Paolo; Franchini, Matteo; Franchino, Silvia; Francis, David; Frank, Tal; Franz, Sebastien; Fraternali, Marco; Fratina, Sasa; French, Sky; Friedrich, Conrad; Friedrich, Felix; Froeschl, Robert; Froidevaux, Daniel; Frost, James; Fukunaga, Chikara; Fullana Torregrosa, Esteban; Fulsom, Bryan Gregory; Fuster, Juan; Gabaldon, Carolina; Gabizon, Ofir; Gadfort, Thomas; Gadomski, Szymon; Gagliardi, Guido; Gagnon, Pauline; Galea, Cristina; Gallas, Elizabeth; Gallo, Valentina Santina; Gallop, Bruce; Gallus, Petr; Gan, KK; Gao, Yongsheng; Gaponenko, Andrei; Garberson, Ford; Garcia-Sciveres, Maurice; García, Carmen; García Navarro, José Enrique; Gardner, Robert; Garelli, Nicoletta; Garitaonandia, Hegoi; Garonne, Vincent; Gatti, Claudio; Gaudio, Gabriella; Gaur, Bakul; Gauthier, Lea; Gauzzi, Paolo; Gavrilenko, Igor; Gay, Colin; Gaycken, Goetz; Gazis, Evangelos; Ge, Peng; Gecse, Zoltan; Gee, Norman; Geerts, Daniël Alphonsus Adrianus; Geich-Gimbel, Christoph; Gellerstedt, Karl; Gemme, Claudia; Gemmell, Alistair; Genest, Marie-Hélène; Gentile, Simonetta; George, Matthias; George, Simon; Gerlach, Peter; Gershon, Avi; Geweniger, Christoph; Ghazlane, Hamid; Ghodbane, Nabil; Giacobbe, Benedetto; Giagu, Stefano; Giakoumopoulou, Victoria; Giangiobbe, Vincent; Gianotti, Fabiola; Gibbard, Bruce; Gibson, Adam; Gibson, Stephen; Gillberg, Dag; Gillman, Tony; Gingrich, Douglas; Ginzburg, Jonatan; Giokaris, Nikos; Giordani, MarioPaolo; Giordano, Raffaele; Giorgi, Francesco Michelangelo; Giovannini, Paola; Giraud, Pierre-Francois; Giugni, Danilo; Giunta, Michele; Giusti, Paolo; Gjelsten, Børge Kile; Gladilin, Leonid; Glasman, Claudia; Glatzer, Julian; Glazov, Alexandre; Glitza, Karl-Walter; Glonti, George; Goddard, Jack Robert; Godfrey, Jennifer; Godlewski, Jan; Goebel, Martin; Göpfert, Thomas; Goeringer, Christian; Gössling, Claus; Goldfarb, Steven; Golling, Tobias; Gomes, Agostinho; Gomez Fajardo, Luz Stella; Gonçalo, Ricardo; Goncalves Pinto Firmino Da Costa, Joao; Gonella, Laura; Gonzalez, Saul; González de la Hoz, Santiago; Gonzalez Parra, Garoe; Gonzalez Silva, Laura; Gonzalez-Sevilla, Sergio; Goodson, Jeremiah Jet; Goossens, Luc; Gorbounov, Petr Andreevich; Gordon, Howard; Gorelov, Igor; Gorfine, Grant; Gorini, Benedetto; Gorini, Edoardo; Gorišek, Andrej; Gornicki, Edward; Gosdzik, Bjoern; Goshaw, Alfred; Gosselink, Martijn; Gostkin, Mikhail Ivanovitch; Gough Eschrich, Ivo; Gouighri, Mohamed; Goujdami, Driss; Goulette, Marc Phillippe; Goussiou, Anna; Goy, Corinne; Gozpinar, Serdar; Grabowska-Bold, Iwona; Grafström, Per; Grahn, Karl-Johan; Grancagnolo, Francesco; Grancagnolo, Sergio; Grassi, Valerio; Gratchev, Vadim; Grau, Nathan; Gray, Heather; Gray, Julia Ann; Graziani, Enrico; Grebenyuk, Oleg; Greenshaw, Timothy; Greenwood, Zeno Dixon; Gregersen, Kristian; Gregor, Ingrid-Maria; Grenier, Philippe; Griffiths, Justin; Grigalashvili, Nugzar; Grillo, Alexander; Grinstein, Sebastian; Gris, Philippe Luc Yves; Grishkevich, Yaroslav; Grivaz, Jean-Francois; Gross, Eilam; Grosse-Knetter, Joern; Groth-Jensen, Jacob; Grybel, Kai; Guest, Daniel; Guicheney, Christophe; Guindon, Stefan; Gul, Umar; Guler, Hulya; Gunther, Jaroslav; Guo, Bin; Guo, Jun; Gutierrez, Phillip; Guttman, Nir; Gutzwiller, Olivier; Guyot, Claude; Gwenlan, Claire; Gwilliam, Carl; Haas, Andy; Haas, Stefan; Haber, Carl; Hadavand, Haleh Khani; Hadley, David; Haefner, Petra; Hahn, Ferdinand; Haider, Stefan; Hajduk, Zbigniew; Hakobyan, Hrachya; Hall, David; Haller, Johannes; Hamacher, Klaus; Hamal, Petr; Hamer, Matthias; Hamilton, Andrew; Hamilton, Samuel; Han, Liang; Hanagaki, Kazunori; Hanawa, Keita; Hance, Michael; Handel, Carsten; Hanke, Paul; Hansen, John Renner; Hansen, Jørgen Beck; Hansen, Jorn Dines; Hansen, Peter Henrik; Hansson, Per; Hara, Kazuhiko; Hare, Gabriel; Harenberg, Torsten; Harkusha, Siarhei; Harper, Devin; Harrington, Robert; Harris, Orin; Hartert, Jochen; Hartjes, Fred; Haruyama, Tomiyoshi; Harvey, Alex; Hasegawa, Satoshi; Hasegawa, Yoji; Hassani, Samira; Haug, Sigve; Hauschild, Michael; Hauser, Reiner; Havranek, Miroslav; Hawkes, Christopher; Hawkings, Richard John; Hawkins, Anthony David; Hawkins, Donovan; Hayakawa, Takashi; Hayashi, Takayasu; Hayden, Daniel; Hays, Chris; Hayward, Helen; Haywood, Stephen; He, Mao; Head, Simon; Hedberg, Vincent; Heelan, Louise; Heim, Sarah; Heinemann, Beate; Heisterkamp, Simon; Helary, Louis; Heller, Claudio; Heller, Matthieu; Hellman, Sten; Hellmich, Dennis; Helsens, Clement; Henderson, Robert; Henke, Michael; Henrichs, Anna; Henriques Correia, Ana Maria; Henrot-Versille, Sophie; Hensel, Carsten; Henß, Tobias; Medina Hernandez, Carlos; Hernández Jiménez, Yesenia; Herrberg, Ruth; Herten, Gregor; Hertenberger, Ralf; Hervas, Luis; Hesketh, Gavin Grant; Hessey, Nigel; Higón-Rodriguez, Emilio; Hill, John; Hiller, Karl Heinz; Hillert, Sonja; Hillier, Stephen; Hinchliffe, Ian; Hines, Elizabeth; Hirose, Minoru; Hirsch, Florian; Hirschbuehl, Dominic; Hobbs, John; Hod, Noam; Hodgkinson, Mark; Hodgson, Paul; Hoecker, Andreas; Hoeferkamp, Martin; Hoffman, Julia; Hoffmann, Dirk; Hohlfeld, Marc; Holder, Martin; Holmgren, Sven-Olof; Holy, Tomas; Holzbauer, Jenny; Hong, Tae Min; Hooft van Huysduynen, Loek; Horner, Stephan; Hostachy, Jean-Yves; Hou, Suen; Hoummada, Abdeslam; Howard, Jacob; Howarth, James; Hristova, Ivana; Hrivnac, Julius; Hryn'ova, Tetiana; Hsu, Pai-hsien Jennifer; Hsu, Shih-Chieh; Hu, Diedi; Hubacek, Zdenek; Hubaut, Fabrice; Huegging, Fabian; Huelsing, Tobias Alexander; Huettmann, Antje; Huffman, Todd Brian; Hughes, Emlyn; Hughes, Gareth; Huhtinen, Mika; Hurwitz, Martina; Husemann, Ulrich; Huseynov, Nazim; Huston, Joey; Huth, John; Iacobucci, Giuseppe; Iakovidis, Georgios; Ibbotson, Michael; Ibragimov, Iskander; Iconomidou-Fayard, Lydia; Idarraga, John; Iengo, Paolo; Igonkina, Olga; Ikegami, Yoichi; Ikeno, Masahiro; Iliadis, Dimitrios; Ilic, Nikolina; Ince, Tayfun; Inigo-Golfin, Joaquin; Ioannou, Pavlos; Iodice, Mauro; Iordanidou, Kalliopi; Ippolito, Valerio; Irles Quiles, Adrian; Isaksson, Charlie; Ishino, Masaya; Ishitsuka, Masaki; Ishmukhametov, Renat; Issever, Cigdem; Istin, Serhat; Ivashin, Anton; Iwanski, Wieslaw; Iwasaki, Hiroyuki; Izen, Joseph; Izzo, Vincenzo; Jackson, Brett; Jackson, John; Jackson, Paul; Jaekel, Martin; Jain, Vivek; Jakobs, Karl; Jakobsen, Sune; Jakoubek, Tomas; Jakubek, Jan; Jana, Dilip; Jansen, Eric; Jansen, Hendrik; Jantsch, Andreas; Janus, Michel; Jarlskog, Göran; Jeanty, Laura; Jen-La Plante, Imai; Jennens, David; Jenni, Peter; Loevschall-Jensen, Ask Emil; Jež, Pavel; Jézéquel, Stéphane; Jha, Manoj Kumar; Ji, Haoshuang; Ji, Weina; Jia, Jiangyong; Jiang, Yi; Jimenez Belenguer, Marcos; Jin, Shan; Jinnouchi, Osamu; Joergensen, Morten Dam; Joffe, David; Johansen, Marianne; Johansson, Erik; Johansson, Per; Johnert, Sebastian; Johns, Kenneth; Jon-And, Kerstin; Jones, Graham; Jones, Roger; Jones, Tim; Joram, Christian; Jorge, Pedro; Joshi, Kiran Daniel; Jovicevic, Jelena; Jovin, Tatjana; Ju, Xiangyang; Jung, Christian; Jungst, Ralph Markus; Juranek, Vojtech; Jussel, Patrick; Juste Rozas, Aurelio; Kabana, Sonja; Kaci, Mohammed; Kaczmarska, Anna; Kadlecik, Peter; Kado, Marumi; Kagan, Harris; Kagan, Michael; Kajomovitz, Enrique; Kalinin, Sergey; Kalinovskaya, Lidia; Kama, Sami; Kanaya, Naoko; Kaneda, Michiru; Kaneti, Steven; Kanno, Takayuki; Kantserov, Vadim; Kanzaki, Junichi; Kaplan, Benjamin; Kapliy, Anton; Kaplon, Jan; Kar, Deepak; Karagounis, Michael; Karakostas, Konstantinos; Karnevskiy, Mikhail; Kartvelishvili, Vakhtang; Karyukhin, Andrey; Kashif, Lashkar; Kasieczka, Gregor; Kass, Richard; Kastanas, Alex; Kataoka, Mayuko; Kataoka, Yousuke; Katsoufis, Elias; Katzy, Judith; Kaushik, Venkatesh; Kawagoe, Kiyotomo; Kawamoto, Tatsuo; Kawamura, Gen; Kayl, Manuel; Kazama, Shingo; Kazanin, Vassili; Kazarinov, Makhail; Keeler, Richard; Kehoe, Robert; Keil, Markus; Kekelidze, George; Keller, John; Kenyon, Mike; Kepka, Oldrich; Kerschen, Nicolas; Kerševan, Borut Paul; Kersten, Susanne; Kessoku, Kohei; Keung, Justin; Khalil-zada, Farkhad; Khandanyan, Hovhannes; Khanov, Alexander; Kharchenko, Dmitri; Khodinov, Alexander; Khomich, Andrei; Khoo, Teng Jian; Khoriauli, Gia; Khoroshilov, Andrey; Khovanskiy, Valery; Khramov, Evgeniy; Khubua, Jemal; Kim, Hyeon Jin; Kim, Shinhong; Kimura, Naoki; Kind, Oliver; King, Barry; King, Matthew; King, Robert Steven Beaufoy; Kirk, Julie; Kiryunin, Andrey; Kishimoto, Tomoe; Kisielewska, Danuta; Kitamura, Takumi; Kittelmann, Thomas; Kiuchi, Kenji; Kladiva, Eduard; Klein, Max; Klein, Uta; Kleinknecht, Konrad; Klemetti, Miika; Klier, Amit; Klimek, Pawel; Klimentov, Alexei; Klingenberg, Reiner; Klinger, Joel Alexander; Klinkby, Esben; Klioutchnikova, Tatiana; Klok, Peter; Klous, Sander; Kluge, Eike-Erik; Kluge, Thomas; Kluit, Peter; Kluth, Stefan; Knecht, Neil; Kneringer, Emmerich; Knoops, Edith; Knue, Andrea; Ko, Byeong Rok; Kobayashi, Tomio; Kobel, Michael; Kocian, Martin; Kodys, Peter; Köneke, Karsten; König, Adriaan; Koenig, Sebastian; Köpke, Lutz; Koetsveld, Folkert; Koevesarki, Peter; Koffas, Thomas; Koffeman, Els; Kogan, Lucy Anne; Kohlmann, Simon; Kohn, Fabian; Kohout, Zdenek; Kohriki, Takashi; Koi, Tatsumi; Kolachev, Guennady; Kolanoski, Hermann; Kolesnikov, Vladimir; Koletsou, Iro; Koll, James; Kollefrath, Michael; Komar, Aston; Komori, Yuto; Kondo, Takahiko; Kono, Takanori; Kononov, Anatoly; Konoplich, Rostislav; Konstantinidis, Nikolaos; Koperny, Stefan; Korcyl, Krzysztof; Kordas, Kostantinos; Korn, Andreas; Korol, Aleksandr; Korolkov, Ilya; Korolkova, Elena; Korotkov, Vladislav; Kortner, Oliver; Kortner, Sandra; Kostyukhin, Vadim; Kotov, Sergey; Kotov, Vladislav; Kotwal, Ashutosh; Kourkoumelis, Christine; Kouskoura, Vasiliki; Koutsman, Alex; Kowalewski, Robert Victor; Kowalski, Tadeusz; Kozanecki, Witold; Kozhin, Anatoly; Kral, Vlastimil; Kramarenko, Viktor; Kramberger, Gregor; Krasny, Mieczyslaw Witold; Krasznahorkay, Attila; Kraus, Jana; Kreiss, Sven; Krejci, Frantisek; Kretzschmar, Jan; Krieger, Nina; Krieger, Peter; Kroeninger, Kevin; Kroha, Hubert; Kroll, Joe; Kroseberg, Juergen; Krstic, Jelena; Kruchonak, Uladzimir; Krüger, Hans; Kruker, Tobias; Krumnack, Nils; Krumshteyn, Zinovii; Kubota, Takashi; Kuday, Sinan; Kuehn, Susanne; Kugel, Andreas; Kuhl, Thorsten; Kuhn, Dietmar; Kukhtin, Victor; Kulchitsky, Yuri; Kuleshov, Sergey; Kummer, Christian; Kuna, Marine; Kunkle, Joshua; Kupco, Alexander; Kurashige, Hisaya; Kurata, Masakazu; Kurochkin, Yurii; Kus, Vlastimil; Kuwertz, Emma Sian; Kuze, Masahiro; Kvita, Jiri; Kwee, Regina; La Rosa, Alessandro; La Rotonda, Laura; Labarga, Luis; Labbe, Julien; Lablak, Said; Lacasta, Carlos; Lacava, Francesco; Lacker, Heiko; Lacour, Didier; Lacuesta, Vicente Ramón; Ladygin, Evgueni; Lafaye, Remi; Laforge, Bertrand; Lagouri, Theodota; Lai, Stanley; Laisne, Emmanuel; Lamanna, Massimo; Lambourne, Luke; Lampen, Caleb; Lampl, Walter; Lancon, Eric; Landgraf, Ulrich; Landon, Murrough; Lane, Jenna; Lang, Valerie Susanne; Lange, Clemens; Lankford, Andrew; Lanni, Francesco; Lantzsch, Kerstin; Laplace, Sandrine; Lapoire, Cecile; Laporte, Jean-Francois; Lari, Tommaso; Larner, Aimee; Lassnig, Mario; Laurelli, Paolo; Lavorini, Vincenzo; Lavrijsen, Wim; Laycock, Paul; Le Dortz, Olivier; Le Guirriec, Emmanuel; Le Maner, Christophe; Le Menedeu, Eve; LeCompte, Thomas; Ledroit-Guillon, Fabienne Agnes Marie; Lee, Hurng-Chun; Lee, Jason; Lee, Shih-Chang; Lee, Lawrence; Lefebvre, Michel; Legendre, Marie; Legger, Federica; Leggett, Charles; Lehmacher, Marc; Lehmann Miotto, Giovanna; Lei, Xiaowen; Leite, Marco Aurelio Lisboa; Leitner, Rupert; Lellouch, Daniel; Lemmer, Boris; Lendermann, Victor; Leney, Katharine; Lenz, Tatiana; Lenzen, Georg; Lenzi, Bruno; Leonhardt, Kathrin; Leontsinis, Stefanos; Lepold, Florian; Leroy, Claude; Lessard, Jean-Raphael; Lester, Christopher; Lester, Christopher Michael; Levêque, Jessica; Levin, Daniel; Levinson, Lorne; Lewis, Adrian; Lewis, George; Leyko, Agnieszka; Leyton, Michael; Li, Bo; Li, Haifeng; Li, Shu; Li, Xuefei; Liang, Zhijun; Liao, Hongbo; Liberti, Barbara; Lichard, Peter; Lichtnecker, Markus; Lie, Ki; Liebig, Wolfgang; Limbach, Christian; Limosani, Antonio; Limper, Maaike; Lin, Simon; Linde, Frank; Linnemann, James; Lipeles, Elliot; Lipniacka, Anna; Liss, Tony; Lissauer, David; Lister, Alison; Litke, Alan; Liu, Chuanlei; Liu, Dong; Liu, Hao; Liu, Jianbei; Liu, Lulu; Liu, Minghui; Liu, Yanwen; Livan, Michele; Livermore, Sarah; Lleres, Annick; Llorente Merino, Javier; Lloyd, Stephen; Lobodzinska, Ewelina; Loch, Peter; Lockman, William; Loddenkoetter, Thomas; Loebinger, Fred; Loginov, Andrey; Loh, Chang Wei; Lohse, Thomas; Lohwasser, Kristin; Lokajicek, Milos; Lombardo, Vincenzo Paolo; Long, Robin Eamonn; Lopes, Lourenco; Lopez Mateos, David; Lorenz, Jeanette; Lorenzo Martinez, Narei; Losada, Marta; Loscutoff, Peter; Lo Sterzo, Francesco; Losty, Michael; Lou, Xinchou; Lounis, Abdenour; Loureiro, Karina; Love, Jeremy; Love, Peter; Lowe, Andrew; Lu, Feng; Lubatti, Henry; Luci, Claudio; Lucotte, Arnaud; Ludwig, Andreas; Ludwig, Dörthe; Ludwig, Inga; Ludwig, Jens; Luehring, Frederick; Luijckx, Guy; Lukas, Wolfgang; Lumb, Debra; Luminari, Lamberto; Lund, Esben; Lund-Jensen, Bengt; Lundberg, Björn; Lundberg, Johan; Lundberg, Olof; Lundquist, Johan; Lungwitz, Matthias; Lynn, David; Lytken, Else; Ma, Hong; Ma, Lian Liang; Maccarrone, Giovanni; Macchiolo, Anna; Maček, Boštjan; Machado Miguens, Joana; Mackeprang, Rasmus; Madaras, Ronald; Mader, Wolfgang; Maenner, Reinhard; Maeno, Tadashi; Mättig, Peter; Mättig, Stefan; Magnoni, Luca; Magradze, Erekle; Mahboubi, Kambiz; Mahmoud, Sara; Mahout, Gilles; Maiani, Camilla; Maidantchik, Carmen; Maio, Amélia; Majewski, Stephanie; Makida, Yasuhiro; Makovec, Nikola; Mal, Prolay; Malaescu, Bogdan; Malecki, Pawel; Malecki, Piotr; Maleev, Victor; Malek, Fairouz; Mallik, Usha; Malon, David; Malone, Caitlin; Maltezos, Stavros; Malyshev, Vladimir; Malyukov, Sergei; Mameghani, Raphael; Mamuzic, Judita; Manabe, Atsushi; Mandelli, Luciano; Mandić, Igor; Mandrysch, Rocco; Maneira, José; Mangeard, Pierre-Simon; Manhaes de Andrade Filho, Luciano; Manjarres Ramos, Joany Andreina; Mann, Alexander; Manning, Peter; Manousakis-Katsikakis, Arkadios; Mansoulie, Bruno; Mapelli, Alessandro; Mapelli, Livio; March, Luis; Marchand, Jean-Francois; Marchese, Fabrizio; Marchiori, Giovanni; Marcisovsky, Michal; Marino, Christopher; Marroquim, Fernando; Marshall, Zach; Martens, Kalen; Marti, Lukas Fritz; Marti-Garcia, Salvador; Martin, Brian; Martin, Brian Thomas; Martin, Jean-Pierre; Martin, Tim; Martin, Victoria Jane; Martin dit Latour, Bertrand; Martin-Haugh, Stewart; Martinez, Mario; Martinez Outschoorn, Verena; Martyniuk, Alex; Marx, Marilyn; Marzano, Francesco; Marzin, Antoine; Masetti, Lucia; Mashimo, Tetsuro; Mashinistov, Ruslan; Masik, Jiri; Maslennikov, Alexey; Massa, Ignazio; Massaro, Graziano; Massol, Nicolas; Mastrandrea, Paolo; Mastroberardino, Anna; Masubuchi, Tatsuya; Matricon, Pierre; Matsunaga, Hiroyuki; Matsushita, Takashi; Mattravers, Carly; Maurer, Julien; Maxfield, Stephen; Mayne, Anna; Mazini, Rachid; Mazur, Michael; Mazzaferro, Luca; Mazzanti, Marcello; Mc Donald, Jeffrey; Mc Kee, Shawn Patrick; McCarn, Allison; McCarthy, Robert; McCarthy, Tom; McCubbin, Norman; McFarlane, Kenneth; Mcfayden, Josh; Mchedlidze, Gvantsa; Mclaughlan, Tom; McMahon, Steve; McPherson, Robert; Meade, Andrew; Mechnich, Joerg; Mechtel, Markus; Medinnis, Mike; Meera-Lebbai, Razzak; Meguro, Tatsuma; Mehdiyev, Rashid; Mehlhase, Sascha; Mehta, Andrew; Meier, Karlheinz; Meirose, Bernhard; Melachrinos, Constantinos; Mellado Garcia, Bruce Rafael; Meloni, Federico; Mendoza Navas, Luis; Meng, Zhaoxia; Mengarelli, Alberto; Menke, Sven; Meoni, Evelin; Mercurio, Kevin Michael; Mermod, Philippe; Merola, Leonardo; Meroni, Chiara; Merritt, Frank; Merritt, Hayes; Messina, Andrea; Metcalfe, Jessica; Mete, Alaettin Serhan; Meyer, Carsten; Meyer, Christopher; Meyer, Jean-Pierre; Meyer, Jochen; Meyer, Joerg; Meyer, Thomas Christian; Miao, Jiayuan; Michal, Sebastien; Micu, Liliana; Middleton, Robin; Migas, Sylwia; Mijović, Liza; Mikenberg, Giora; Mikestikova, Marcela; Mikuž, Marko; Miller, David; Miller, Robert; Mills, Bill; Mills, Corrinne; Milov, Alexander; Milstead, David; Milstein, Dmitry; Minaenko, Andrey; Miñano Moya, Mercedes; Minashvili, Irakli; Mincer, Allen; Mindur, Bartosz; Mineev, Mikhail; Ming, Yao; Mir, Lluisa-Maria; Mirabelli, Giovanni; Mitrevski, Jovan; Mitsou, Vasiliki A; Mitsui, Shingo; Miyagawa, Paul; Mjörnmark, Jan-Ulf; Moa, Torbjoern; Moeller, Victoria; Mönig, Klaus; Möser, Nicolas; Mohapatra, Soumya; Mohr, Wolfgang; Moles-Valls, Regina; Monk, James; Monnier, Emmanuel; Montejo Berlingen, Javier; Monticelli, Fernando; Monzani, Simone; Moore, Roger; Moorhead, Gareth; Mora Herrera, Clemencia; Moraes, Arthur; Morange, Nicolas; Morel, Julien; Morello, Gianfranco; Moreno, Deywis; Moreno Llácer, María; Morettini, Paolo; Morgenstern, Marcus; Morii, Masahiro; Morley, Anthony Keith; Mornacchi, Giuseppe; Morris, John; Morvaj, Ljiljana; Moser, Hans-Guenther; Mosidze, Maia; Moss, Josh; Mount, Richard; Mountricha, Eleni; Mouraviev, Sergei; Moyse, Edward; Mueller, Felix; Mueller, James; Mueller, Klemens; Müller, Thomas; Mueller, Timo; Muenstermann, Daniel; Munwes, Yonathan; Murray, Bill; Mussche, Ido; Musto, Elisa; Myagkov, Alexey; Myska, Miroslav; Nadal, Jordi; Nagai, Koichi; Nagai, Ryo; Nagano, Kunihiro; Nagarkar, Advait; Nagasaka, Yasushi; Nagel, Martin; Nairz, Armin Michael; Nakahama, Yu; Nakamura, Koji; Nakamura, Tomoaki; Nakano, Itsuo; Nanava, Gizo; Napier, Austin; Narayan, Rohin; Nash, Michael; Nattermann, Till; Naumann, Thomas; Navarro, Gabriela; Neal, Homer; Nechaeva, Polina; Neep, Thomas James; Negri, Andrea; Negri, Guido; Negrini, Matteo; Nektarijevic, Snezana; Nelson, Andrew; Nelson, Timothy Knight; Nemecek, Stanislav; Nemethy, Peter; Nepomuceno, Andre Asevedo; Nessi, Marzio; Neubauer, Mark; Neumann, Manuel; Neusiedl, Andrea; Neves, Ricardo; Nevski, Pavel; Newman, Paul; Nguyen Thi Hong, Van; Nickerson, Richard; Nicolaidou, Rosy; Nicquevert, Bertrand; Niedercorn, Francois; Nielsen, Jason; Nikiforou, Nikiforos; Nikiforov, Andriy; Nikolaenko, Vladimir; Nikolic-Audit, Irena; Nikolics, Katalin; Nikolopoulos, Konstantinos; Nilsen, Henrik; Nilsson, Paul; Ninomiya, Yoichi; Nisati, Aleandro; Nisius, Richard; Nobe, Takuya; Nodulman, Lawrence; Nomachi, Masaharu; Nomidis, Ioannis; Norberg, Scarlet; Nordberg, Markus; Norton, Peter; Novakova, Jana; Nozaki, Mitsuaki; Nozka, Libor; Nugent, Ian Michael; Nuncio-Quiroz, Adriana-Elizabeth; Nunes Hanninger, Guilherme; Nunnemann, Thomas; Nurse, Emily; O'Brien, Brendan Joseph; O'Neale, Steve; O'Neil, Dugan; O'Shea, Val; Oakes, Louise Beth; Oakham, Gerald; Oberlack, Horst; Ocariz, Jose; Ochi, Atsuhiko; Oda, Susumu; Odaka, Shigeru; Odier, Jerome; Ogren, Harold; Oh, Alexander; Oh, Seog; Ohm, Christian; Ohshima, Takayoshi; Okawa, Hideki; Okumura, Yasuyuki; Okuyama, Toyonobu; Olariu, Albert; Olchevski, Alexander; Olivares Pino, Sebastian Andres; Oliveira, Miguel Alfonso; Oliveira Damazio, Denis; Oliver Garcia, Elena; Olivito, Dominick; Olszewski, Andrzej; Olszowska, Jolanta; Onofre, António; Onyisi, Peter; Oram, Christopher; Oreglia, Mark; Oren, Yona; Orestano, Domizia; Orlando, Nicola; Orlov, Iliya; Oropeza Barrera, Cristina; Orr, Robert; Osculati, Bianca; Ospanov, Rustem; Osuna, Carlos; Otero y Garzon, Gustavo; Ottersbach, John; Ouchrif, Mohamed; Ouellette, Eric; Ould-Saada, Farid; Ouraou, Ahmimed; Ouyang, Qun; Ovcharova, Ana; Owen, Mark; Owen, Simon; Ozcan, Veysi Erkcan; Ozturk, Nurcan; Pacheco Pages, Andres; Padilla Aranda, Cristobal; Pagan Griso, Simone; Paganis, Efstathios; Pahl, Christoph; Paige, Frank; Pais, Preema; Pajchel, Katarina; Palacino, Gabriel; Paleari, Chiara; Palestini, Sandro; Pallin, Dominique; Palma, Alberto; Palmer, Jody; Pan, Yibin; Panagiotopoulou, Evgenia; Pani, Priscilla; Panikashvili, Natalia; Panitkin, Sergey; Pantea, Dan; Papadelis, Aras; Papadopoulou, Theodora; Paramonov, Alexander; Paredes Hernandez, Daniela; Park, Woochun; Parker, Andy; Parodi, Fabrizio; Parsons, John; Parzefall, Ulrich; Pashapour, Shabnaz; Pasqualucci, Enrico; Passaggio, Stefano; Passeri, Antonio; Pastore, Fernanda; Pastore, Francesca; Pásztor, Gabriella; Pataraia, Sophio; Patel, Nikhul; Pater, Joleen; Patricelli, Sergio; Pauly, Thilo; Pecsy, Martin; Pedraza Lopez, Sebastian; Pedraza Morales, Maria Isabel; Peleganchuk, Sergey; Pelikan, Daniel; Peng, Haiping; Penning, Bjoern; Penson, Alexander; Penwell, John; Perantoni, Marcelo; Perez, Kerstin; Perez Cavalcanti, Tiago; Perez Codina, Estel; Pérez García-Estañ, María Teresa; Perez Reale, Valeria; Perini, Laura; Pernegger, Heinz; Perrino, Roberto; Perrodo, Pascal; Peshekhonov, Vladimir; Peters, Krisztian; Petersen, Brian; Petersen, Jorgen; Petersen, Troels; Petit, Elisabeth; Petridis, Andreas; Petridou, Chariclia; Petrolo, Emilio; Petrucci, Fabrizio; Petschull, Dennis; Petteni, Michele; Pezoa, Raquel; Phan, Anna; Phillips, Peter William; Piacquadio, Giacinto; Picazio, Attilio; Piccaro, Elisa; Piccinini, Maurizio; Piec, Sebastian Marcin; Piegaia, Ricardo; Pignotti, David; Pilcher, James; Pilkington, Andrew; Pina, João Antonio; Pinamonti, Michele; Pinder, Alex; Pinfold, James; Pinto, Belmiro; Pizio, Caterina; Plamondon, Mathieu; Pleier, Marc-Andre; Plotnikova, Elena; Poblaguev, Andrei; Poddar, Sahill; Podlyski, Fabrice; Poggioli, Luc; Pohl, David-leon; Pohl, Martin; Polesello, Giacomo; Policicchio, Antonio; Polini, Alessandro; Poll, James; Polychronakos, Venetios; Pomeroy, Daniel; Pommès, Kathy; Pontecorvo, Ludovico; Pope, Bernard; Popeneciu, Gabriel Alexandru; Popovic, Dragan; Poppleton, Alan; Portell Bueso, Xavier; Pospelov, Guennady; Pospisil, Stanislav; Potrap, Igor; Potter, Christina; Potter, Christopher; Poulard, Gilbert; Poveda, Joaquin; Pozdnyakov, Valery; Prabhu, Robindra; Pralavorio, Pascal; Pranko, Aliaksandr; Prasad, Srivas; Pravahan, Rishiraj; Prell, Soeren; Pretzl, Klaus Peter; Price, Darren; Price, Joe; Price, Lawrence; Prieur, Damien; Primavera, Margherita; Prokofiev, Kirill; Prokoshin, Fedor; Protopopescu, Serban; Proudfoot, James; Prudent, Xavier; Przybycien, Mariusz; Przysiezniak, Helenka; Psoroulas, Serena; Ptacek, Elizabeth; Pueschel, Elisa; Purdham, John; Purohit, Milind; Puzo, Patrick; Pylypchenko, Yuriy; Qian, Jianming; Quadt, Arnulf; Quarrie, David; Quayle, William; Quinonez, Fernando; Raas, Marcel; Radescu, Voica; Radloff, Peter; Rador, Tonguc; Ragusa, Francesco; Rahal, Ghita; Rahimi, Amir; Rahm, David; Rajagopalan, Srinivasan; Rammensee, Michael; Rammes, Marcus; Randle-Conde, Aidan Sean; Randrianarivony, Koloina; Rauscher, Felix; Rave, Tobias Christian; Raymond, Michel; Read, Alexander Lincoln; Rebuzzi, Daniela; Redelbach, Andreas; Redlinger, George; Reece, Ryan; Reeves, Kendall; Reinherz-Aronis, Erez; Reinsch, Andreas; Reisinger, Ingo; Rembser, Christoph; Ren, Zhongliang; Renaud, Adrien; Rescigno, Marco; Resconi, Silvia; Resende, Bernardo; Reznicek, Pavel; Rezvani, Reyhaneh; Richter, Robert; Richter-Was, Elzbieta; Ridel, Melissa; Rijpstra, Manouk; Rijssenbeek, Michael; Rimoldi, Adele; Rinaldi, Lorenzo; Rios, Ryan Randy; Riu, Imma; Rivoltella, Giancesare; Rizatdinova, Flera; Rizvi, Eram; Robertson, Steven; Robichaud-Veronneau, Andree; Robinson, Dave; Robinson, James; Robson, Aidan; Rocha de Lima, Jose Guilherme; Roda, Chiara; Roda Dos Santos, Denis; Roe, Adam; Roe, Shaun; Røhne, Ole; Rolli, Simona; Romaniouk, Anatoli; Romano, Marino; Romeo, Gaston; Romero Adam, Elena; Rompotis, Nikolaos; Roos, Lydia; Ros, Eduardo; Rosati, Stefano; Rosbach, Kilian; Rose, Anthony; Rose, Matthew; Rosenbaum, Gabriel; Rosenberg, Eli; Rosendahl, Peter Lundgaard; Rosenthal, Oliver; Rosselet, Laurent; Rossetti, Valerio; Rossi, Elvira; Rossi, Leonardo Paolo; Rotaru, Marina; Roth, Itamar; Rothberg, Joseph; Rousseau, David; Royon, Christophe; Rozanov, Alexander; Rozen, Yoram; Ruan, Xifeng; Rubbo, Francesco; Rubinskiy, Igor; Ruckstuhl, Nicole; Rud, Viacheslav; Rudolph, Christian; Rudolph, Gerald; Rühr, Frederik; Ruiz-Martinez, Aranzazu; Rumyantsev, Leonid; Rurikova, Zuzana; Rusakovich, Nikolai; Rutherfoord, John; Ruwiedel, Christoph; Ruzicka, Pavel; Ryabov, Yury; Rybar, Martin; Rybkin, Grigori; Ryder, Nick; Saavedra, Aldo; Sadeh, Iftach; Sadrozinski, Hartmut; Sadykov, Renat; Safai Tehrani, Francesco; Sakamoto, Hiroshi; Salamanna, Giuseppe; Salamon, Andrea; Saleem, Muhammad; Salek, David; Salihagic, Denis; Salnikov, Andrei; Salt, José; Salvachua Ferrando, Belén; Salvatore, Daniela; Salvatore, Pasquale Fabrizio; Salvucci, Antonio; Salzburger, Andreas; Sampsonidis, Dimitrios; Samset, Björn Hallvard; Sanchez, Arturo; Sanchez Martinez, Victoria; Sandaker, Heidi; Sander, Heinz Georg; Sanders, Michiel; Sandhoff, Marisa; Sandoval, Tanya; Sandoval, Carlos; Sandstroem, Rikard; Sankey, Dave; Sansoni, Andrea; Santamarina Rios, Cibran; Santoni, Claudio; Santonico, Rinaldo; Santos, Helena; Saraiva, João; Sarangi, Tapas; Sarkisyan-Grinbaum, Edward; Sarri, Francesca; Sartisohn, Georg; Sasaki, Osamu; Sasaki, Yuichi; Sasao, Noboru; Satsounkevitch, Igor; Sauvage, Gilles; Sauvan, Emmanuel; Sauvan, Jean-Baptiste; Savard, Pierre; Savinov, Vladimir; Savu, Dan Octavian; Sawyer, Lee; Saxon, David; Saxon, James; Sbarra, Carla; Sbrizzi, Antonio; Scannicchio, Diana; Scarcella, Mark; Schaarschmidt, Jana; Schacht, Peter; Schaefer, Douglas; Schäfer, Uli; Schaepe, Steffen; Schaetzel, Sebastian; Schaffer, Arthur; Schaile, Dorothee; Schamberger, R. Dean; Schamov, Andrey; Scharf, Veit; Schegelsky, Valery; Scheirich, Daniel; Schernau, Michael; Scherzer, Max; Schiavi, Carlo; Schieck, Jochen; Schioppa, Marco; Schlenker, Stefan; Schmidt, Evelyn; Schmieden, Kristof; Schmitt, Christian; Schmitt, Sebastian; Schmitz, Martin; Schneider, Basil; Schnoor, Ulrike; Schoening, Andre; Schorlemmer, Andre Lukas; Schott, Matthias; Schouten, Doug; Schovancova, Jaroslava; Schram, Malachi; Schroeder, Christian; Schroer, Nicolai; Schultens, Martin Johannes; Schultes, Joachim; Schultz-Coulon, Hans-Christian; Schulz, Holger; Schumacher, Markus; Schumm, Bruce; Schune, Philippe; Schwanenberger, Christian; Schwartzman, Ariel; Schwemling, Philippe; Schwienhorst, Reinhard; Schwierz, Rainer; Schwindling, Jerome; Schwindt, Thomas; Schwoerer, Maud; Sciolla, Gabriella; Scott, Bill; Searcy, Jacob; Sedov, George; Sedykh, Evgeny; Seidel, Sally; Seiden, Abraham; Seifert, Frank; Seixas, José; Sekhniaidze, Givi; Sekula, Stephen; Selbach, Karoline Elfriede; Seliverstov, Dmitry; Sellden, Bjoern; Sellers, Graham; Seman, Michal; Semprini-Cesari, Nicola; Serfon, Cedric; Serin, Laurent; Serkin, Leonid; Seuster, Rolf; Severini, Horst; Sfyrla, Anna; Shabalina, Elizaveta; Shamim, Mansoora; Shan, Lianyou; Shank, James; Shao, Qi Tao; Shapiro, Marjorie; Shatalov, Pavel; Shaw, Kate; Sherman, Daniel; Sherwood, Peter; Shibata, Akira; Shimizu, Shima; Shimojima, Makoto; Shin, Taeksu; Shiyakova, Maria; Shmeleva, Alevtina; Shochet, Mel; Short, Daniel; Shrestha, Suyog; Shulga, Evgeny; Shupe, Michael; Sicho, Petr; Sidoti, Antonio; Siegert, Frank; Sijacki, Djordje; Silbert, Ohad; Silva, José; Silver, Yiftah; Silverstein, Daniel; Silverstein, Samuel; Simak, Vladislav; Simard, Olivier; Simic, Ljiljana; Simion, Stefan; Simioni, Eduard; Simmons, Brinick; Simoniello, Rosa; Simonyan, Margar; Sinervo, Pekka; Sinev, Nikolai; Sipica, Valentin; Siragusa, Giovanni; Sircar, Anirvan; Sisakyan, Alexei; Sivoklokov, Serguei; Sjölin, Jörgen; Sjursen, Therese; Skinnari, Louise Anastasia; Skottowe, Hugh Philip; Skovpen, Kirill; Skubic, Patrick; Slater, Mark; Slavicek, Tomas; Sliwa, Krzysztof; Smakhtin, Vladimir; Smart, Ben; Smirnov, Sergei; Smirnov, Yury; Smirnova, Lidia; Smirnova, Oxana; Smith, Ben Campbell; Smith, Douglas; Smith, Kenway; Smizanska, Maria; Smolek, Karel; Snesarev, Andrei; Snow, Steve; Snow, Joel; Snyder, Scott; Sobie, Randall; Sodomka, Jaromir; Soffer, Abner; Solans, Carlos; Solar, Michael; Solc, Jaroslav; Soldatov, Evgeny; Soldevila, Urmila; Solfaroli Camillocci, Elena; Solodkov, Alexander; Solovyanov, Oleg; Solovyev, Victor; Soni, Nitesh; Sopko, Vit; Sopko, Bruno; Sosebee, Mark; Soualah, Rachik; Soukharev, Andrey; Spagnolo, Stefania; Spanò, Francesco; Spighi, Roberto; Spigo, Giancarlo; Spiwoks, Ralf; Spousta, Martin; Spreitzer, Teresa; Spurlock, Barry; St Denis, Richard Dante; Stahlman, Jonathan; Stamen, Rainer; Stanecka, Ewa; Stanek, Robert; Stanescu, Cristian; Stanescu-Bellu, Madalina; Stapnes, Steinar; Starchenko, Evgeny; Stark, Jan; Staroba, Pavel; Starovoitov, Pavel; Staszewski, Rafal; Staude, Arnold; Stavina, Pavel; Steele, Genevieve; Steinbach, Peter; Steinberg, Peter; Stekl, Ivan; Stelzer, Bernd; Stelzer, Harald Joerg; Stelzer-Chilton, Oliver; Stenzel, Hasko; Stern, Sebastian; Stewart, Graeme; Stillings, Jan Andre; Stockton, Mark; Stoerig, Kathrin; Stoicea, Gabriel; Stonjek, Stefan; Strachota, Pavel; Stradling, Alden; Straessner, Arno; Strandberg, Jonas; Strandberg, Sara; Strandlie, Are; Strang, Michael; Strauss, Emanuel; Strauss, Michael; Strizenec, Pavol; Ströhmer, Raimund; Strom, David; Strong, John; Stroynowski, Ryszard; Strube, Jan; Stugu, Bjarne; Stumer, Iuliu; Stupak, John; Sturm, Philipp; Styles, Nicholas Adam; Soh, Dart-yin; Su, Dong; Subramania, Halasya Siva; Succurro, Antonella; Sugaya, Yorihito; Suhr, Chad; Suk, Michal; Sulin, Vladimir; Sultansoy, Saleh; Sumida, Toshi; Sun, Xiaohu; Sundermann, Jan Erik; Suruliz, Kerim; Susinno, Giancarlo; Sutton, Mark; Suzuki, Yu; Suzuki, Yuta; Svatos, Michal; Swedish, Stephen; Sykora, Ivan; Sykora, Tomas; Sánchez, Javier; Ta, Duc; Tackmann, Kerstin; Taffard, Anyes; Tafirout, Reda; Taiblum, Nimrod; Takahashi, Yuta; Takai, Helio; Takashima, Ryuichi; Takeda, Hiroshi; Takeshita, Tohru; Takubo, Yosuke; Talby, Mossadek; Talyshev, Alexey; Tamsett, Matthew; Tanaka, Junichi; Tanaka, Reisaburo; Tanaka, Satoshi; Tanaka, Shuji; Tanasijczuk, Andres Jorge; Tani, Kazutoshi; Tannoury, Nancy; Tapprogge, Stefan; Tardif, Dominique; Tarem, Shlomit; Tarrade, Fabien; Tartarelli, Giuseppe Francesco; Tas, Petr; Tasevsky, Marek; Tassi, Enrico; Tatarkhanov, Mous; Tayalati, Yahya; Taylor, Christopher; Taylor, Frank; Taylor, Geoffrey; Taylor, Wendy; Teinturier, Marthe; Teischinger, Florian Alfred; Teixeira Dias Castanheira, Matilde; Teixeira-Dias, Pedro; Temming, Kim Katrin; Ten Kate, Herman; Teng, Ping-Kun; Terada, Susumu; Terashi, Koji; Terron, Juan; Testa, Marianna; Teuscher, Richard; Therhaag, Jan; Theveneaux-Pelzer, Timothée; Thoma, Sascha; Thomas, Juergen; Thompson, Emily; Thompson, Paul; Thompson, Peter; Thompson, Stan; Thomsen, Lotte Ansgaard; Thomson, Evelyn; Thomson, Mark; Thong, Wai Meng; Thun, Rudolf; Tian, Feng; Tibbetts, Mark James; Tic, Tomáš; Tikhomirov, Vladimir; Tikhonov, Yury; Timoshenko, Sergey; Tipton, Paul; Tisserant, Sylvain; Todorov, Theodore; Todorova-Nova, Sharka; Toggerson, Brokk; Tojo, Junji; Tokár, Stanislav; Tokushuku, Katsuo; Tollefson, Kirsten; Tomoto, Makoto; Tompkins, Lauren; Toms, Konstantin; Tonoyan, Arshak; Topfel, Cyril; Topilin, Nikolai; Torchiani, Ingo; Torrence, Eric; Torres, Heberth; Torró Pastor, Emma; Toth, Jozsef; Touchard, Francois; Tovey, Daniel; Trefzger, Thomas; Tremblet, Louis; Tricoli, Alesandro; Trigger, Isabel Marian; Trincaz-Duvoid, Sophie; Tripiana, Martin; Triplett, Nathan; Trischuk, William; Trocmé, Benjamin; Troncon, Clara; Trottier-McDonald, Michel; Trzebinski, Maciej; Trzupek, Adam; Tsarouchas, Charilaos; Tseng, Jeffrey; Tsiakiris, Menelaos; Tsiareshka, Pavel; Tsionou, Dimitra; Tsipolitis, Georgios; Tsiskaridze, Shota; Tsiskaridze, Vakhtang; Tskhadadze, Edisher; Tsukerman, Ilya; Tsulaia, Vakhtang; Tsung, Jieh-Wen; Tsuno, Soshi; Tsybychev, Dmitri; Tua, Alan; Tudorache, Alexandra; Tudorache, Valentina; Tuggle, Joseph; Turala, Michal; Turecek, Daniel; Turk Cakir, Ilkay; Turlay, Emmanuel; Turra, Ruggero; Tuts, Michael; Tykhonov, Andrii; Tylmad, Maja; Tyndel, Mike; Tzanakos, George; Uchida, Kirika; Ueda, Ikuo; Ueno, Ryuichi; Ugland, Maren; Uhlenbrock, Mathias; Uhrmacher, Michael; Ukegawa, Fumihiko; Unal, Guillaume; Undrus, Alexander; Unel, Gokhan; Unno, Yoshinobu; Urbaniec, Dustin; Usai, Giulio; Uslenghi, Massimiliano; Vacavant, Laurent; Vacek, Vaclav; Vachon, Brigitte; Vahsen, Sven; Valenta, Jan; Valentinetti, Sara; Valero, Alberto; Valkar, Stefan; Valladolid Gallego, Eva; Vallecorsa, Sofia; Valls Ferrer, Juan Antonio; Van Der Deijl, Pieter; van der Geer, Rogier; van der Graaf, Harry; Van Der Leeuw, Robin; van der Poel, Egge; van der Ster, Daniel; van Eldik, Niels; van Gemmeren, Peter; van Vulpen, Ivo; Vanadia, Marco; Vandelli, Wainer; Vaniachine, Alexandre; Vankov, Peter; Vannucci, Francois; Vari, Riccardo; Varol, Tulin; Varouchas, Dimitris; Vartapetian, Armen; Varvell, Kevin; Vassilakopoulos, Vassilios; Vazeille, Francois; Vazquez Schroeder, Tamara; Vegni, Guido; Veillet, Jean-Jacques; Veloso, Filipe; Veness, Raymond; Veneziano, Stefano; Ventura, Andrea; Ventura, Daniel; Venturi, Manuela; Venturi, Nicola; Vercesi, Valerio; Verducci, Monica; Verkerke, Wouter; Vermeulen, Jos; Vest, Anja; Vetterli, Michel; Vichou, Irene; Vickey, Trevor; Vickey Boeriu, Oana Elena; Viehhauser, Georg; Viel, Simon; Villa, Mauro; Villaplana Perez, Miguel; Vilucchi, Elisabetta; Vincter, Manuella; Vinek, Elisabeth; Vinogradov, Vladimir; Virchaux, Marc; Virzi, Joseph; Vitells, Ofer; Viti, Michele; Vivarelli, Iacopo; Vives Vaque, Francesc; Vlachos, Sotirios; Vladoiu, Dan; Vlasak, Michal; Vogel, Adrian; Vokac, Petr; Volpi, Guido; Volpi, Matteo; Volpini, Giovanni; von der Schmitt, Hans; von Radziewski, Holger; von Toerne, Eckhard; Vorobel, Vit; Vorwerk, Volker; Vos, Marcel; Voss, Rudiger; Voss, Thorsten Tobias; Vossebeld, Joost; Vranjes, Nenad; Vranjes Milosavljevic, Marija; Vrba, Vaclav; Vreeswijk, Marcel; Vu Anh, Tuan; Vuillermet, Raphael; Vukotic, Ilija; Wagner, Wolfgang; Wagner, Peter; Wahlen, Helmut; Wahrmund, Sebastian; Wakabayashi, Jun; Walch, Shannon; Walder, James; Walker, Rodney; Walkowiak, Wolfgang; Wall, Richard; Waller, Peter; Walsh, Brian; Wang, Chiho; Wang, Haichen; Wang, Hulin; Wang, Jike; Wang, Jin; Wang, Rui; Wang, Song-Ming; Wang, Tan; Warburton, Andreas; Ward, Patricia; Warsinsky, Markus; Washbrook, Andrew; Wasicki, Christoph; Watanabe, Ippei; Watkins, Peter; Watson, Alan; Watson, Ian; Watson, Miriam; Watts, Gordon; Watts, Stephen; Waugh, Anthony; Waugh, Ben; Weber, Michele; Weber, Pavel; Weidberg, Anthony; Weigell, Philipp; Weingarten, Jens; Weiser, Christian; Wellenstein, Hermann; Wells, Phillippa; Wenaus, Torre; Wendland, Dennis; Weng, Zhili; Wengler, Thorsten; Wenig, Siegfried; Wermes, Norbert; Werner, Matthias; Werner, Per; Werth, Michael; Wessels, Martin; Wetter, Jeffrey; Weydert, Carole; Whalen, Kathleen; Wheeler-Ellis, Sarah Jane; White, Andrew; White, Martin; White, Sebastian; Whitehead, Samuel Robert; Whiteson, Daniel; Whittington, Denver; Wicek, Francois; Wicke, Daniel; Wickens, Fred; Wiedenmann, Werner; Wielers, Monika; Wienemann, Peter; Wiglesworth, Craig; Wiik-Fuchs, Liv Antje Mari; Wijeratne, Peter Alexander; Wildauer, Andreas; Wildt, Martin Andre; Wilhelm, Ivan; Wilkens, Henric George; Will, Jonas Zacharias; Williams, Eric; Williams, Hugh; Willis, William; Willocq, Stephane; Wilson, John; Wilson, Michael Galante; Wilson, Alan; Wingerter-Seez, Isabelle; Winkelmann, Stefan; Winklmeier, Frank; Wittgen, Matthias; Wollstadt, Simon Jakob; Wolter, Marcin Wladyslaw; Wolters, Helmut; Wong, Wei-Cheng; Wooden, Gemma; Wosiek, Barbara; Wotschack, Jorg; Woudstra, Martin; Wozniak, Krzysztof; Wraight, Kenneth; Wright, Michael; Wrona, Bozydar; Wu, Sau Lan; Wu, Xin; Wu, Yusheng; Wulf, Evan; Wynne, Benjamin; Xella, Stefania; Xiao, Meng; Xie, Song; Xu, Chao; Xu, Da; Yabsley, Bruce; Yacoob, Sahal; Yamada, Miho; Yamaguchi, Hiroshi; Yamamoto, Akira; Yamamoto, Kyoko; Yamamoto, Shimpei; Yamamura, Taiki; Yamanaka, Takashi; Yamaoka, Jared; Yamazaki, Takayuki; Yamazaki, Yuji; Yan, Zhen; Yang, Haijun; Yang, Un-Ki; Yang, Yi; Yang, Zhaoyu; Yanush, Serguei; Yao, Liwen; Yao, Yushu; Yasu, Yoshiji; Ybeles Smit, Gabriel Valentijn; Ye, Jingbo; Ye, Shuwei; Yilmaz, Metin; Yoosoofmiya, Reza; Yorita, Kohei; Yoshida, Riktura; Young, Charles; Young, Christopher John; Youssef, Saul; Yu, Dantong; Yu, Jaehoon; Yu, Jie; Yuan, Li; Yurkewicz, Adam; Byszewski, Marcin; Zabinski, Bartlomiej; Zaidan, Remi; Zaitsev, Alexander; Zajacova, Zuzana; Zanello, Lucia; Zaytsev, Alexander; Zeitnitz, Christian; Zeman, Martin; Zemla, Andrzej; Zendler, Carolin; Zenin, Oleg; Ženiš, Tibor; Zinonos, Zinonas; Zenz, Seth; Zerwas, Dirk; Zevi della Porta, Giovanni; Zhan, Zhichao; Zhang, Dongliang; Zhang, Huaqiao; Zhang, Jinlong; Zhang, Xueyao; Zhang, Zhiqing; Zhao, Long; Zhao, Tianchi; Zhao, Zhengguo; Zhemchugov, Alexey; Zhong, Jiahang; Zhou, Bing; Zhou, Ning; Zhou, Yue; Zhu, Cheng Guang; Zhu, Hongbo; Zhu, Junjie; Zhu, Yingchun; Zhuang, Xuai; Zhuravlov, Vadym; Zieminska, Daria; Zimin, Nikolai; Zimmermann, Robert; Zimmermann, Simone; Zimmermann, Stephanie; Ziolkowski, Michael; Zitoun, Robert; Živković, Lidija; Zmouchko, Viatcheslav; Zobernig, Georg; Zoccoli, Antonio; zur Nedden, Martin; Zutshi, Vishnu; Zwalinski, Lukasz

2013-08-06

The measurement of several event shape variables is presented in minimum bias pp collisions at a center-of-mass energy of 7 TeV using the ATLAS detector at the LHC. The observables studied are the transverse thrust, thrust minor and transverse sphericity, each defined using the momenta perpendicular to the beam direction of the final state charged particles. Events with at least six charged particles are selected. In addition to the differential distributions, the evolution of each event shape variable as a function of the leading charged particle transverse momentum, charged particle multiplicity and summed transverse momentum is presented. Predictions from several Monte Carlo models have been compared with data and they show significant deviations from data.

Transverse modes of a bunched beam with space charge dominated impedance

Directory of Open Access Journals (Sweden)

V. Balbekov

2009-12-01

Full Text Available Transverse coherent oscillations of a bunched beam in a ring accelerator are considered with space charge dominated impedance, taking into account linear synchrotron oscillations. A general equation of the bunch eigenmodes is derived, its exact analytical solution is presented for boxcar bunch, and numerical solutions are found for several realistic models. Both low and high synchrotron frequency approximations are considered and compared, fields of their applicability are determined, and some estimations are developed in the intermediate region. It is shown that most of the bunch eigenmodes are stabilized by Landau damping due to the space charge produced tune spread.

Combined effects of space charge and energetic disorder on photocurrent efficiency loss of field-dependent organic photovoltaic devices

International Nuclear Information System (INIS)

Yoon, Sangcheol; Hwang, Inchan; Park, Byoungchoo

2015-01-01

The loss of photocurrent efficiency by space-charge effects in organic solar cells with energetic disorder was investigated to account for how energetic disorder incorporates space-charge effects, utilizing a drift-diffusion model with field-dependent charge-pair dissociation and suppressed bimolecular recombination. Energetic disorder, which induces the Poole–Frenkel behavior of charge carrier mobility, is known to decrease the mobility of charge carriers and thus reduces photovoltaic performance. We found that even if the mobilities are the same in the absence of space-charge effects, the degree of energetic disorder can be an additional parameter affecting photocurrent efficiency when space-charge effects occur. Introducing the field-dependence parameter that reflects the energetic disorder, the behavior of efficiency loss with energetic disorder can differ depending on which charge carrier is subject to energetic disorder. While the energetic disorder that is applied to higher-mobility charge carriers decreases photocurrent efficiency further, the efficiency loss can be suppressed when energetic disorder is applied to lower-mobility charge carriers. (paper)

One-carrier free space charge motion under applied voltage

International Nuclear Information System (INIS)

Camargo, P.C.; Ferreira, G.F.L.

1976-01-01

The system of partial differential equations describing the one-carrier free space-charge motion under a given applied voltage is transformed into a system of two ordinary differential equations. The method is applied to find the external current injection [pt

The Role of Shape on Electronic Structure and Charge Transport in Faceted PbSe Nanocrystals

KAUST Repository

Kaushik, Ananth P.; Lukose, Binit; Clancy, Paulette

2014-01-01

We have determined the effect of shape on the charge transport characteristics of nanocrystals. Our study looked at the explicit determination of the electronic properties of faceted nanocrystals that essentially probe the limit of current

Charge-signal multiplication mediated by urea wires inside Y-shaped carbon nanotubes

International Nuclear Information System (INIS)

Lv, Mei; Liu, Zengrong; He, Bing; Xiu, Peng; Tu, Yusong

2014-01-01

In previous studies, we reported molecular dynamics (MD) simulations showing that single-file water wires confined inside Y-shaped single-walled carbon nanotubes (Y-SWNTs) held strong and robust capability to convert and multiply charge signals [Y. S. Tu, P. Xiu, R. Z. Wan, J. Hu, R. H. Zhou, and H. P. Fang, Proc. Natl. Acad. Sci. U.S.A. 106, 18120 (2009); Y. Tu, H. Lu, Y. Zhang, T. Huynh, and R. Zhou, J. Chem. Phys. 138, 015104 (2013)]. It is fascinating to see whether the signal multiplication can be realized by other kinds of polar molecules with larger dipole moments (which make the experimental realization easier). In this article, we use MD simulations to study the urea-mediated signal conversion and multiplication with Y-SWNTs. We observe that when a Y-SWNT with an external charge of magnitude 1.0 e (the model of a signal at the single-electron level) is solvated in 1 M urea solutions, urea can induce drying of the Y-SWNT and fill its interiors in single-file, forming Y-shaped urea wires. The external charge can effectively control the dipole orientation of the urea wire inside the main channel (i.e., the signal can be readily converted), and this signal can further be multiplied into 2 (or more) output signals by modulating dipole orientations of urea wires in bifurcated branch channels of the Y-SWNT. This remarkable signal transduction capability arises from the strong dipole-induced ordering of urea wires under extreme confinement. We also discuss the advantage of urea as compared with water in the signal multiplication, as well as the robustness and biological implications of our findings. This study provides the possibility for multiplying signals by using urea molecules (or other polar organic molecules) with Y-shaped nanochannels and might also help understand the mechanism behind signal conduction in both physical and biological systems

Search for space charge effects in the ICARUS T600 LAr-TPC

Science.gov (United States)

Torti, Marta

2016-11-01

Space charge in Liquid Argon Time Projection Chamber is due to the accumu- lation of positive ions, produced by ionizing tracks crossing the detector, which slowly flow toward the cathode. As a consequence, electric field distortions may arise, thus hindering the possibility to produce faithful 3D images of the ionizing events. The presence of space charge becomes relevant for large TPCs operating at surface or at shallow depths, where cosmic ray flux is high. These effects could interest the next phase of the ICARUS T600 detector, which will be deployed at shallow depths as a Far Detector for Short Baseline Neutrino experiment at FNAL dedicated to sterile neutrino searches. In 2001, the first ICARUS T600 module (T300) operated at surface in Pavia (Italy), recording cosmic ray data. In this work, a sample of cosmic muon tracks from the 2001 run was analyzed and results on space charge effects in LAr-TPCs are shown.

Search for space charge effects in the ICARUS T600 LAr-TPC

International Nuclear Information System (INIS)

Torti, Marta

2016-01-01

Space charge in Liquid Argon Time Projection Chamber is due to the accumu- lation of positive ions, produced by ionizing tracks crossing the detector, which slowly flow toward the cathode. As a consequence, electric field distortions may arise, thus hindering the possibility to produce faithful 3D images of the ionizing events. The presence of space charge becomes relevant for large TPCs operating at surface or at shallow depths, where cosmic ray flux is high. These effects could interest the next phase of the ICARUS T600 detector, which will be deployed at shallow depths as a Far Detector for Short Baseline Neutrino experiment at FNAL dedicated to sterile neutrino searches. In 2001, the first ICARUS T600 module (T300) operated at surface in Pavia (Italy), recording cosmic ray data. In this work, a sample of cosmic muon tracks from the 2001 run was analyzed and results on space charge effects in LAr-TPCs are shown

The effects of noise over the complete space of diffusion tensor shape.

Science.gov (United States)

Gahm, Jin Kyu; Kindlmann, Gordon; Ennis, Daniel B

2014-01-01

Diffusion tensor magnetic resonance imaging (DT-MRI) is a technique used to quantify the microstructural organization of biological tissues. Multiple images are necessary to reconstruct the tensor data and each acquisition is subject to complex thermal noise. As such, measures of tensor invariants, which characterize components of tensor shape, derived from the tensor data will be biased from their true values. Previous work has examined this bias, but over a narrow range of tensor shape. Herein, we define the mathematics for constructing a tensor from tensor invariants, which permits an intuitive and principled means for building tensors with a complete range of tensor shape and salient microstructural properties. Thereafter, we use this development to evaluate by simulation the effects of noise on characterizing tensor shape over the complete space of tensor shape for three encoding schemes with different SNR and gradient directions. We also define a new framework for determining the distribution of the true values of tensor invariants given their measures, which provides guidance about the confidence the observer should have in the measures. Finally, we present the statistics of tensor invariant estimates over the complete space of tensor shape to demonstrate how the noise sensitivity of tensor invariants varies across the space of tensor shape as well as how the imaging protocol impacts measures of tensor invariants. Copyright © 2013 Elsevier B.V. All rights reserved.

Biochemistry students' ideas about shape and charge in enzyme-substrate interactions.

Science.gov (United States)

Linenberger, Kimberly J; Bretz, Stacey Lowery

2014-01-01

Biochemistry is a visual discipline that requires students to develop an understanding of numerous representations. However, there is very little known about what students actually understand about the representations that are used to communicate ideas in biochemistry. This study investigated biochemistry students' understanding of multiple representations of enzyme-substrate interactions through both student interviews (N = 25) and responses by a national sample (N = 707) to the Enzyme-Substrate Interactions Concept Inventory. This manuscript reports the findings regarding one category of misconceptions measured by the concept inventory, namely, students' understandings of shape and charge in the context of enzyme-substrate interactions. Students interpret molecular representations depicting such interactions by determining the complementarity between enzyme and substrate by focusing upon charge and hydrogen bonding, but with a disregard for stereochemistry. Copyright © 2014 by The International Union of Biochemistry and Molecular Biology.

Effect of applied DC voltages and temperatures on space charge behaviour of multi-layer oil-paper insulation

Energy Technology Data Exchange (ETDEWEB)

Tang Chao; Liao Ruijin [The State Key Laboratory of Power Transmission Equipment and System Security and New Technology, Chongqing University (China); Chen, G [School of Electronics and Computer Science, University of Southampton (United Kingdom); Fu, M, E-mail: tangchao_1981@163.co [AVERA T and D Technology Centre, Stafford (United Kingdom)

2009-08-01

In this paper, space charge in a multi-layer oil-paper insulation system was investigated using the pulsed electroacoustic (PEA) technique. A series of measurements had been carried following subjection of the insulation system to different applied voltages and different temperatures. Charge behaviours in the insulation system were analyzed and the influence of temperature on charge dynamics was discussed. The test results shows that homocharge injection takes place under all the test conditions, the applied DC voltage mainly affects the amount of space charge, while the temperature has greater influence on the distribution and mobility of space charge inside oil-paper samples.

Jumbo Space Environment Simulation and Spacecraft Charging Chamber Characterization

Science.gov (United States)

2015-04-09

probes for Jumbo. Both probes are produced by Trek Inc. Trek probe model 370 is capable of -3 to 3kV and has an extremely fast, 50µs/kV response to...changing surface potentials. Trek probe 341B is capable of -20 to 20kV with a 200 µs/kV response time. During our charging experiments the probe sits...unlimited. 12 REFERENCES [1] R. D. Leach and M. B. Alexander, "Failures and anomalies attributed to spacecraft charging," NASA RP-1375, Marshall Space

Space charge effects in a bending magnet system

International Nuclear Information System (INIS)

Lee, E.P.; Close, E.; Smith, L.

1987-03-01

In order to examine problems and phenomena associated with space charge in a beam bending system, the beam dynamics code HICURB has been written. Its principal features include momentum variations, vertical and horizontal envelope dynamics coupled to the off-axis centroid, curvature effect on fields, and images. Preliminary results for an achromatic lattice configuration are presented

Space charge effects in a bending magnet system

International Nuclear Information System (INIS)

Lee, E.P.; Close, E.; Smith, L.

1987-01-01

In order to examine problems and phenomena associated with space charge in a beam bending system, the beam dynamics code HICURB has been written. Its principal features include momentum variations, vertical and horizontal envelope dynamics coupled to the off-axis centroid, curvature effect on fields, and images. Preliminary results for an achromatic lattice configuration are presented

Space-charge effects in vacuum-deposited polyimide layer

Czech Academy of Sciences Publication Activity Database

Zhivkov, I.; Strijkova, V.; Spassova, E.; Danev, G.; Nešpůrek, Stanislav; Iwamoto, M.

2005-01-01

Roč. 7, č. 1 (2005), s. 245-248 ISSN 1454-4164 R&D Projects: GA MŠk ME 558 Grant - others:Ministry of Education and Science(BG) X-1322 Institutional research plan: CEZ:AV0Z40500505 Keywords : polyimide * electrical conductivity * space-charge spectroscopy Subject RIV: CD - Macromolecular Chemistry Impact factor: 1.138, year: 2005

Moisture effect on the dielectric response and space charge behaviour of mineral oil impregnated paper insulation

International Nuclear Information System (INIS)

Hao Jian; Liao Ruijin; Chen, George

2011-01-01

Dielectric response and space charge behaviour of oil-paper insulation sample with different moisture contents were investigated using the frequency dielectric spectroscopy (FDS) and the pulsed electroacoustic (PEA) technique, respectively. The influence of moisture on the dielectric response and space charge behaviour of oil impregnated paper insulation was analysed. Results show that the moisture has great effect on the FDS and space charge behaviour of oil impregnated paper insulation. In the frequency range of 10 -2 ∼10 6 Hz, the conductivity and the capacitance of oil impregnated paper increases with its moisture content. The space charge distribution of oil-paper sample with lower and higher moisture contents is very different from each other. The higher the moisture concentration of the oil impregnated paper, the easier the negative charge penetration into the insulation paper. There is a significant amount of positive charge accumulated at the paper-paper interface near to the cathode for oilpaper sample with lower moisture content. However, the positive charge appears in the middle layer paper for oil-paper sample with higher moisture content. Due to the high conductivity, the charge trapped in the oil-paper sample with higher moisture content disappears much faster than that in the oil-paper sample with lower moisture content after removing the voltage.

Moisture effect on the dielectric response and space charge behaviour of mineral oil impregnated paper insulation

Energy Technology Data Exchange (ETDEWEB)

Hao Jian; Liao Ruijin [State Key Laboratory of Power Transmission Equipment and System Security and New Technology, Chongqing University (China); Chen, George, E-mail: jh210v@ecs.soton.ac.uk [School of Electronics and Computer Science, University of Southampton (United Kingdom)

2011-08-12

Dielectric response and space charge behaviour of oil-paper insulation sample with different moisture contents were investigated using the frequency dielectric spectroscopy (FDS) and the pulsed electroacoustic (PEA) technique, respectively. The influence of moisture on the dielectric response and space charge behaviour of oil impregnated paper insulation was analysed. Results show that the moisture has great effect on the FDS and space charge behaviour of oil impregnated paper insulation. In the frequency range of 10{sup -2}{approx}10{sup 6}Hz, the conductivity and the capacitance of oil impregnated paper increases with its moisture content. The space charge distribution of oil-paper sample with lower and higher moisture contents is very different from each other. The higher the moisture concentration of the oil impregnated paper, the easier the negative charge penetration into the insulation paper. There is a significant amount of positive charge accumulated at the paper-paper interface near to the cathode for oilpaper sample with lower moisture content. However, the positive charge appears in the middle layer paper for oil-paper sample with higher moisture content. Due to the high conductivity, the charge trapped in the oil-paper sample with higher moisture content disappears much faster than that in the oil-paper sample with lower moisture content after removing the voltage.

Plasma-induced evolution behavior of space-charge-limited current for multiple-needle cathodes

International Nuclear Information System (INIS)

Li Limin; Liu Lie; Zhang Jun; Wen Jianchun; Liu Yonggui; Wan Hong

2009-01-01

Properties of the plasma and beam flow produced by tufted carbon fiber cathodes in a diode powered by a ∼500 kV, ∼400 ns pulse are investigated. Under electric fields of 230-260 kV cm -1 , the electron current density was in the range 210-280 A cm -2 , and particularly at the diode gap of 20 mm, a maximum beam power density of about 120 MW cm -2 was obtained. It was found that space-charge-limited current exhibited an evolution behavior as the accelerating pulse proceeded. There exists a direct relation between the movement of plasma within the diode and the evolution of space-charge-limited current. Initially in the accelerating pulse, the application of strong electric fields caused the emission sites to explode, forming cathode flares or plasma spots, and in this stage the space-charge-limited current was approximately described by a multiple-needle cathode model. As the pulse proceeded, these plasma spots merged and expanded towards the anode, thus increasing the emission area and shortening the diode gap, and the corresponding space-charge-limited current followed a planar cathode model. Finally, the space-charge-limited current is developed from a unipolar flow into a bipolar flow as a result of the appearance of anode plasma. In spite of the nonuniform distribution of cathode plasma, the cross-sectional uniformity of the extracted electron beam is satisfactory. The plasma expansion within the diode is found to be a major factor in the diode perveance growth and instability. These results show that these types of cathodes can offer promising applications for high-power microwave tubes.

Modal description of longitudinal space-charge fields in pulse-driven free-electron devices

Directory of Open Access Journals (Sweden)

Yu. Lurie

2010-05-01

Full Text Available In pulsed-beam free-electron devices, longitudinal space-charge fields result in collective effects leading to an expansion of short electron bunches along their trajectory. This effect restricts an application of intense ultrashort electron pulses in free-electron radiation sources. A careful theoretical treatment is required in order to achieve an accurate description of the self-fields and the resulted electron beam dynamics. In this paper, longitudinal space-charge fields are considered in the framework of a three-dimensional, space-frequency approach. The model is based on the expansion of the total electromagnetic field (including self-fields in terms of transverse eigenmodes of the (cold cavity, in which the field is excited and propagates. The electromagnetic field, originally obtained in the model as a solution of the wave equation, is shown to satisfy also Gauss’s law. We applied the theory to derive an analytical expression for the longitudinal electric field of a pointlike charge, moving along a waveguide at a constant velocity. This enables consideration and study of the role played by different terms of the resulted expressions, such as components arising from forward and backward waves, propagating waves, and under cutoff frequencies, and so on. Possible simplifications in evaluation of longitudinal space-charge fields are discussed.

Thermal pulse measurements of space charge distributions under an applied electric field in thin films

International Nuclear Information System (INIS)

Zheng, Feihu; An, Zhenlian; Zhang, Yewen; Liu, Chuandong; Lin, Chen; Lei, Qingquan

2013-01-01

The thermal pulse method is a powerful method to measure space charge and polarization distributions in thin dielectric films, but a complicated calibration procedure is necessary to obtain the real distribution. In addition, charge dynamic behaviour under an applied electric field cannot be observed by the classical thermal pulse method. In this work, an improved thermal pulse measuring system with a supplemental circuit for applying high voltage is proposed to realize the mapping of charge distribution in thin dielectric films under an applied field. The influence of the modified measuring system on the amplitude and phase of the thermal pulse response current are evaluated. Based on the new measuring system, an easy calibration approach is presented with some practical examples. The newly developed system can observe space charge evolution under an applied field, which would be very helpful in understanding space charge behaviour in thin films. (paper)

A modified space charge routine for LINAC beam dynamics codes

International Nuclear Information System (INIS)

Valero, S.; Lapostolle, P.; Lombardi, A.M.; Tanke, E.; Warner, D.

1994-01-01

In 1991 a space charge calculation for bunched beams with three-dimensional ellipsoidal symmetry was proposed for the PARMILA code, replacing the usual SCHEFF routines: it removes the cylindrical symmetry needed for the Fast Fourier Transform method and avoids the point to point interaction computation, where the number of simulation points is limited. This routine has now been improved with the introduction of two (or more) ellipsoids, giving a good representation of actual, pear-shaped bunches (unlike the 3-D ellipsoidal assumption). The ellipsoidal density distributions are computed with a new method, avoiding the difficulty caused by statistical effects, encountered near the centre (the axis in 2-D problems) by the previous method. It also provides a check of the ellipsoidal symmetry for each part of the distribution. Finally, the Fourier analysis reported in 1991 has been replaced by a very convenient Hermite expansion, which gives a simple but accurate representation of practical distributions. Introduced in the new, versatile beam dynamics code, DYNAC, it should provide a good tool for the study of the effects of the various parameters responsible for the halo formation in high intensity linacs. (authors). 11 refs

Space charge physics for particle accelerators

CERN Document Server

Hofmann, Ingo

2017-01-01

Understanding and controlling the physics of space charge effects in linear and circular proton and ion accelerators are essential to their operation, and to future high-intensity facilities. This book presents the status quo of this field from a theoretical perspective, compares analytical approaches with multi-particle computer simulations and – where available – with experiments. It discusses fundamental concepts of phase space motion, matched beams and modes of perturbation, along with mathematical models of analysis – from envelope to Vlasov-Poisson equations. The main emphasis is on providing a systematic description of incoherent and coherent resonance phenomena; parametric instabilities and sum modes; mismatch and halo; error driven resonances; and emittance exchange due to anisotropy, as well as the role of Landau damping. Their distinctive features are elaborated in the context of numerous sample simulations, and their potential impacts on beam quality degradation and beam loss are discussed....

The Shaped Charge Concept. Part 2. The History of Shaped Charges

Science.gov (United States)

1990-09-01

research of Evans. Ubbel•ode. LAmurd-Jones, Devonihire, and An&ew. 1hW U.K. Mufied cadmium liners (which probably produce molten jets) msd steel liners...34 Mathematical Jet Theory of Lined Hollow Charges." BRL Report No. 370, U.S. Army Ballistic Research Laboratory. Aberdeen Proving Ground, MD, 18 June

EXPLORING TRANSVERSE BEAM STABILITY IN THE SNS IN THE PRESENCE OF SPACE CHARGE.

Energy Technology Data Exchange (ETDEWEB)

FEDOTOV,A.V.; BLASKIEWICZ,M.; WEI,J.; DANILOV,V.; HOLMES,J.; SHISHLO,A.

2002-06-03

The highest possible intensity in the machine is typically determined by the onset of coherent beam instabilities. Understanding the contribution of various effects to the damping and growth of such instabilities in the regime of strong space charge is thus of crucial importance. In this paper we explore transverse beam stability by numerical simulations using recently implemented models of transverse impedance and three-dimensional space charge. Results are discussed with application to the SNS accumulators.

Minimizing the energy spread within a single bunch by shaping its charge distribution

International Nuclear Information System (INIS)

Loew, G.A.; Wang, J.

1984-06-01

When electrons or positrons in a bunch pass through the periodic structure of a linear accelerator, they leave behind them energy in the form of longitudinal wake fields. The longitudinal fields left behind by early particles in a bunch decrease the energy of later particles. For a linear collider, the energy spread introduced within the bunches by this beam loading effect must be minimized because it limits the degree to which the particles can be focused to a small spot due to chromatic effects in the final focus system. For example, for the SLC, the allowable energy spread is +-0.5%. It has been known for some time that partial compensation of the longitudinal wake field effects can be obtained for any bunch by placing it ahead of the accelerating crest (in space), thereby letting the positive rising sinusoidal field offset the negative beam loading field. The work presented in this report shows that it is possible to obtain complete compensation, i.e., to reduce the energy spread essentially to zero by properly shaping the longitudinal charge distribution of the bunch and by placing it at the correct position on the wave

Geometric shapes inversion method of space targets by ISAR image segmentation

Science.gov (United States)

Huo, Chao-ying; Xing, Xiao-yu; Yin, Hong-cheng; Li, Chen-guang; Zeng, Xiang-yun; Xu, Gao-gui

2017-11-01

The geometric shape of target is an effective characteristic in the process of space targets recognition. This paper proposed a method of shape inversion of space target based on components segmentation from ISAR image. The Radon transformation, Hough transformation, K-means clustering, triangulation will be introduced into ISAR image processing. Firstly, we use Radon transformation and edge detection to extract space target's main body spindle and solar panel spindle from ISAR image. Then the targets' main body, solar panel, rectangular and circular antenna are segmented from ISAR image based on image detection theory. Finally, the sizes of every structural component are computed. The effectiveness of this method is verified using typical targets' simulation data.

Insights into Inverse Materials Design from Phase Transitions in Shape Space

Science.gov (United States)

Cersonsky, Rose; van Anders, Greg; Dodd, Paul M.; Glotzer, Sharon C.

In designing new materials for synthesis, the inverse materials design approach posits that, given a structure, we can predict a building block optimized for self- assembly. How does that building block change as pressure is varied to maintain the same crystal structure? We address this question for entropically stabilized colloidal crystals by working in a generalized statistical thermodynamic ensemble where an alchemical potential variable is fixed and its conjugate variable, particle shape, is allowed to fluctuate. We show that there are multiple regions of shape behavior and phase transitions in shape space between these regions. Furthermore, while past literature has looked towards packing arguments for proposing shape-filling candidate building blocks for structure formation, we show that even at very high pressures, a structure will attain lowest free energy by modifying these space-filling shapes. U.S. Army Research Office under Grant Award No. W911NF-10-1-0518, Emerging Frontiers in Research and Innovation Award EFRI-1240264, National Science Foundation Grant Number ACI- 1053575, XSEDE award DMR 140129, Rackham Merit Fellowship Program.

Chaotic behaviour induced by space charge

International Nuclear Information System (INIS)

Lagniel, J.M.

1994-01-01

In numerous non-linear dynamical systems studied in various disciplines (fluid dynamics, celestial mechanisms, chemistry, biology, economy, ecology...), chaotic motions are generated by the dynamics itself whereas no random force is present. This phenomenon, already studied in the particle accelerator field to understand the beam-beam effect, is also observed in numerical experiments on space-charge dominated beams. Stochasticity threshold and halo formation are discussed for a continuous focusing channel (1D beam) and for a FODO channel (2D beam) with the possibility to take into account the defocusing effects of RF gaps localized between the quadrupoles. (authors). 7 refs., 4 figs

Discrete space charge affected field emission: Flat and hemisphere emitters

Energy Technology Data Exchange (ETDEWEB)

Jensen, Kevin L., E-mail: kevin.jensen@nrl.navy.mil [Code 6854, Naval Research Laboratory, Washington, DC 20375 (United States); Shiffler, Donald A.; Tang, Wilkin [Air Force Research Laboratory, Kirtland AFB, New Mexico 87117 (United States); Rittersdorf, Ian M. [Code 6770, Naval Research Laboratory, Washington, DC 20375 (United States); Lebowitz, Joel L. [Department of Mathematics and Department of Physics, Rutgers University, Piscataway, New Jersey 08854-8019 (United States); Harris, John R. [U.S. Navy Reserve, New Orleans, Louisiana 70143 (United States); Lau, Y. Y. [Department of Nuclear Engineering and Radiological Sciences, University of Michigan, Ann Arbor, Michigan 48109 (United States); Petillo, John J. [Leidos, Billerica, Massachusetts 01821 (United States); Luginsland, John W. [Physics and Electronics Directorate, AFOSR, Arlington, Virginia 22203 (United States)

2015-05-21

Models of space-charge affected thermal-field emission from protrusions, able to incorporate the effects of both surface roughness and elongated field emitter structures in beam optics codes, are desirable but difficult. The models proposed here treat the meso-scale diode region separate from the micro-scale regions characteristic of the emission sites. The consequences of discrete emission events are given for both one-dimensional (sheets of charge) and three dimensional (rings of charge) models: in the former, results converge to steady state conditions found by theory (e.g., Rokhlenko et al. [J. Appl. Phys. 107, 014904 (2010)]) but show oscillatory structure as they do. Surface roughness or geometric features are handled using a ring of charge model, from which the image charges are found and used to modify the apex field and emitted current. The roughness model is shown to have additional constraints related to the discrete nature of electron charge. The ability of a unit cell model to treat field emitter structures and incorporate surface roughness effects inside a beam optics code is assessed.

A Self Consistent Multiprocessor Space Charge Algorithm that is Almost Embarrassingly Parallel

International Nuclear Information System (INIS)

Nissen, Edward; Erdelyi, B.; Manikonda, S.L.

2012-01-01

We present a space charge code that is self consistent, massively parallelizeable, and requires very little communication between computer nodes; making the calculation almost embarrassingly parallel. This method is implemented in the code COSY Infinity where the differential algebras used in this code are important to the algorithm's proper functioning. The method works by calculating the self consistent space charge distribution using the statistical moments of the test particles, and converting them into polynomial series coefficients. These coefficients are combined with differential algebraic integrals to form the potential, and electric fields. The result is a map which contains the effects of space charge. This method allows for massive parallelization since its statistics based solver doesn't require any binning of particles, and only requires a vector containing the partial sums of the statistical moments for the different nodes to be passed. All other calculations are done independently. The resulting maps can be used to analyze the system using normal form analysis, as well as advance particles in numbers and at speeds that were previously impossible.

Dynamics of space and polarization charges of ferroelectric thin films measured by atomic force microscopy

International Nuclear Information System (INIS)

Oh, Y.J.; Lee, J.H.; Jo, W.

2006-01-01

Retention behavior and local hysteresis characteristics in Pb(Zr 0.52 Ti 0.48 )O 3 (PZT) thin films on Pt electrodes have been investigated by electrostatic force microscopy (EFM). A sol-gel method is used to synthesize PZT thin films and drying conditions are carefully explored over a wide range of temperature. Decay and retention mechanisms of single-poled and reverse-poled regions of the ferroelectric thin films are explained by space charge redistribution. Trapping behavior of space charges is dependent on the nature of interface between ferroelectric thin films and bottom electrodes. Local measurement of polarization-electric field curves by EFM shows inhomogeneous space charge entrapment

A prototype silicon detector system for space cosmic-ray charge measurement

Science.gov (United States)

Zhang, Fei; Fan, Rui-Rui; Peng, Wen-Xi; Dong, Yi-Fa; Gong, Ke; Liang, Xiao-Hua; Liu, Ya-Qing; Wang, Huan-Yu

2014-06-01

A readout electronics system used for space cosmic-ray charge measurement for multi-channel silicon detectors is introduced in this paper, including performance measurements. A 64-channel charge sensitive ASIC (VA140) from the IDEAS company is used. With its features of low power consumption, low noise, large dynamic range, and high integration, it can be used in future particle detecting experiments based on silicon detectors.

Space charge in ionization detectors and the NA48 electromagnetic calorimeter

International Nuclear Information System (INIS)

Palestini, S.; Barr, G.D.; Biino, C.; Calafiura, P.; Ceccucci, A.; Cerri, C.; Chollet, J.C.; Cirilli, M.; Cogan, J.; Costantini, F.; Crepe, S.; Cundy, D.; Fantechi, R.; Fayard, L.; Fischer, G.; Formica, A.; Frabetti, P.L.; Funk, W.; Gianoli, A.; Giudici, S.; Gonidec, A.; Gorini, B.; Govi, G.; Iconomidou-Fayard, L.; Kekelidze, V.; Kubischta, W.; Luitz, S.; Mannelli, I.; Martini, M.; Mikulec, I.; Norton, A.; Ocariz, J.; Schinzel, D.; Sozzi, M.; Tatishvili, G.; Tkatchev, A.; Unal, G.; Velasco, M.; Vossnack, O.; Wahl, H.

1999-01-01

The subject of space charge due to positive ions slowly moving in parallel plate ionization chambers is considered. A model for the degradation of the detector response is developed, with particular emphasis on electromagnetic calorimeters.The topics discussed include: (a) the stationary; (b) the time dependent cases; (c) the limit of very large space charge; (d) the electric field dependence of the electron drift velocity; (e) the effect of longitudinal development of showers; (f) the behaviour of the average reductions of response; (g) the non-uniformity of response for different positions of the shower axis inside the cell defined by the electrodes. The NA48 calorimeter is used as application and for comparison of results

Space-charge calculation for bunched beams with 3-D ellipsoidal symmetry

International Nuclear Information System (INIS)

Garnett, R.W.; Wangler, T.P.

1991-01-01

A method for calculating 3-D space-charge forces has been developed that is suitable for bunched beams of either ions or relativistic electrons. The method is based on the analytic relations between charge-density and electric fields for a distribution with 3-D ellipsoidal symmetry in real space. At each step we use a Fourier-series representation for the smooth particle-density function obtained from the distribution of the macroparticles being tracked through the elements of the system. The resulting smooth electric fields reduce the problem of noise from artificial collisions, associated with small numbers of interacting macroparticles. Example calculations will be shown for comparison with other methods. 4 refs., 2 figs., 1 tab

A heterogeneous CPU+GPU Poisson solver for space charge calculations in beam dynamics studies

Energy Technology Data Exchange (ETDEWEB)

Zheng, Dawei; Rienen, Ursula van [University of Rostock, Institute of General Electrical Engineering (Germany)

2016-07-01

In beam dynamics studies in accelerator physics, space charge plays a central role in the low energy regime of an accelerator. Numerical space charge calculations are required, both, in the design phase and in the operation of the machines as well. Due to its efficiency, mostly the Particle-In-Cell (PIC) method is chosen for the space charge calculation. Then, the solution of Poisson's equation for the charge distribution in the rest frame is the most prominent part within the solution process. The Poisson solver directly affects the accuracy of the self-field applied on the charged particles when the equation of motion is solved in the laboratory frame. As the Poisson solver consumes the major part of the computing time in most simulations it has to be as fast as possible since it has to be carried out once per time step. In this work, we demonstrate a novel heterogeneous CPU+GPU routine for the Poisson solver. The novel solver also benefits from our new research results on the utilization of a discrete cosine transform within the classical Hockney and Eastwood's convolution routine.

Metal nanoparticle mediated space charge and its optical control in an organic hole-only device

OpenAIRE

Ligorio, G.; Nardi, M. V.; Steyrleuthner, Robert; Ihiawakrim, D.; Crespo-Monteiro, N.; Brinkmann, M.; Neher, D.; Koch, N.

2017-01-01

We reveal the role of localized space charges in hole-only devices based on an organic semiconductor with embedded metal nanoparticles (MNPs). MNPs act as deep traps for holes and reduce the current density compared to a device without MNPs by a factor of 104 due to the build-up of localized space charge. Dynamic MNPs charged neutrality can be realized during operation by electron transfer from excitons created in the organic matrix, enabling light sensing independent of device bias. In contr...

Benchmark of Space Charge Simulations and Comparison with Experimental Results for High Intensity, Low Energy Accelerators

CERN Document Server

Cousineau, Sarah M

2005-01-01

Space charge effects are a major contributor to beam halo and emittance growth leading to beam loss in high intensity, low energy accelerators. As future accelerators strive towards unprecedented levels of beam intensity and beam loss control, a more comprehensive understanding of space charge effects is required. A wealth of simulation tools have been developed for modeling beams in linacs and rings, and with the growing availability of high-speed computing systems, computationally expensive problems that were inconceivable a decade ago are now being handled with relative ease. This has opened the field for realistic simulations of space charge effects, including detailed benchmarks with experimental data. A great deal of effort is being focused in this direction, and several recent benchmark studies have produced remarkably successful results. This paper reviews the achievements in space charge benchmarking in the last few years, and discusses the challenges that remain.

Elimination of Spurious Fractional Charges in Dissociating Molecules by Correcting the Shape of Approximate Kohn-Sham Potentials.

Science.gov (United States)

Komsa, Darya N; Staroverov, Viktor N

2016-11-08

Standard density-functional approximations often incorrectly predict that heteronuclear diatomic molecules dissociate into fractionally charged atoms. We demonstrate that these spurious charges can be eliminated by adapting the shape-correction method for Kohn-Sham potentials that was originally introduced to improve Rydberg excitation energies [ Phys. Rev. Lett. 2012 , 108 , 253005 ]. Specifically, we show that if a suitably determined fraction of electron charge is added to or removed from a frontier Kohn-Sham orbital level, the approximate Kohn-Sham potential of a stretched molecule self-corrects by developing a semblance of step structure; if this potential is used to obtain the electron density of the neutral molecule, charge delocalization is blocked and spurious fractional charges disappear beyond a certain internuclear distance.

Floating liquid bridge charge dynamics

Science.gov (United States)

Teschke, Omar; Soares, David Mendez; Gomes, Whyllerson Evaristo; Valente Filho, Juracyr Ferraz

2016-01-01

The interaction of liquid with electric fields is investigated in a configuration where up to 13 kV are applied between electrodes resulting in a 106 V/m electric field in the capillaries and where there is the formation of a free-standing fluid bridge in the interelectrode gap. The Mott-Gurney equation was fitted to the measured ionization current vs applied voltage curve which indicates that the ionization rate at the high-voltage anode electrode dimethylsulfoxide (DMSO) interface and space charging in the interelectrode gap determine the floating liquid bridge current for a given cathode-to-anode voltage. Space charge effects were measured in the cathode becker and also at the liquid bridge since the ionized charges at the anode migrate to the bridge outer surface and decrease the interfacial tension from 43 mJ/m2 to 29 mJ/m2. Two distinct structural regions then form the bridge, a charged plastic (bulk modulus ˜100 MPa) conducting outer layer with a surface conductivity of ˜10-9 Ω-1, which shapes and supports the floating fluid structure, and an inner liquid cylinder, where DMSO molecules flow.

Enhanced ionic conductivity in composite materials due to interfacial space charge layers

International Nuclear Information System (INIS)

Dudney, N.J.

1985-01-01

The ionic conductivity of a number of salts (e.g., β-AgI, LiI, CuCl, HgI 2 , etc.) can be enhanced by one to three orders of magnitude with the addition of fine particles of an insoluble and nonconducting material such as Al 2 O 3 or SiO 2 . Typically the conductivity increases with addition of the inert particles and reaches a peak at 10-40 vol % of the particles. The mechanism responsible for the enhanced conductivity of the composite is not understood at this time. Some claim that this effect is due to an increased concentration of charge carriers in a diffuse space charge layer near the charged surface of the particle. The goal of the present study is to test this proposed mechanism by calculating the maximum space charge layer effect and then using this result to estimate the conductivity of a composite with a random distribution of Al 2 O 3 particles. Also, the conductivity of composite systems has been investigated assuming an ordered distribution of particles which are surrounded by a high conductivity layer

Installation and Characterization of Charged Particle Sources for Space Environmental Effects Testing

Science.gov (United States)

Skevington, Jennifer L.

2010-01-01

Charged particle sources are integral devices used by Marshall Space Flight Center s Environmental Effects Branch (EM50) in order to simulate space environments for accurate testing of materials and systems. By using these sources inside custom vacuum systems, materials can be tested to determine charging and discharging properties as well as resistance to sputter damage. This knowledge can enable scientists and engineers to choose proper materials that will not fail in harsh space environments. This paper combines the steps utilized to build a low energy electron gun (The "Skevington 3000") as well as the methods used to characterize the output of both the Skevington 3000 and a manufactured Xenon ion source. Such characterizations include beam flux, beam uniformity, and beam energy. Both sources were deemed suitable for simulating environments in future testing.

Space charge limited conduction in CdSe thin films

Indian Academy of Sciences (India)

Unknown

of trap limited space charge limited conduction (SCLC) at higher voltage. The transition voltage (Vt ) from ohmic to SCLC is found to be quite independent of ambient temperature as well as intensity of illumination. SCLC is explained on the basis of the exponential trap distribution in CdSe films. Trap depths estimated from.

Quantum electrodynamics with arbitrary charge on a noncommutative space

International Nuclear Information System (INIS)

Zhou Wanping; Long Zhengwen; Cai Shaohong

2009-01-01

Using the Seiberg-Witten map, we obtain a quantum electrodynamics on a noncommutative space, which has arbitrary charge and keep the gauge invariance to at the leading order in theta. The one-loop divergence and Compton scattering are reinvestigated. The noncommutative effects are larger than those in ordinary noncommutative quantum electrodynamics. (authors)

Space Charge Modules for PyHEADTAIL

CERN Multimedia

Oeftiger, Adrian

2016-01-01

PyHEADTAIL is a 6D tracking tool developed at CERN to simulate collective effects. We present recent developments of the direct space charge (SC) suite, which is available for both the CPU and GPU. A new 3D particle-in-cell solver with open boundary conditions has been implemented. For the transverse plane, there is a semi-analytical Bassetti-Erskine model as well as 2D self-consistent particle-in-cell solvers with both open and closed boundary conditions. For the longitudinal plane, PyHEADTAIL offers line density derivative models. Simulations with these models are benchmarked with experiments at the injection plateau of CERN’s SPS.

Multigrid Algorithms for the Fast Calculation of Space-Charge Effects in Accelerator Design

NARCIS (Netherlands)

Pöplau, G.; Rienen, van U.; Geer, van der S.B.; Loos, de M.J.

2004-01-01

Numerical prediction of charged particle dynamics in accelerators is essential for the design and understanding of these machines. Methods to calculate the self-fields of the bunch, the so-called space-charge forces, become increasingly important as the demand for high-quality bunches increases. We

A compact T-shaped nanodevice for charge sensing of a tunable double quantum dot in scalable silicon technology

Energy Technology Data Exchange (ETDEWEB)

Tagliaferri, M.L.V., E-mail: marco.tagliaferri@mdm.imm.cnr.it [Laboratorio MDM, CNR-IMM, Via C. Olivetti 2, 20864 Agrate Brianza (MB) (Italy); Dipartimento di Scienza dei Materiali, Università di Milano Bicocca, Via Cozzi 53, 20125 Milano (Italy); Crippa, A. [Laboratorio MDM, CNR-IMM, Via C. Olivetti 2, 20864 Agrate Brianza (MB) (Italy); Dipartimento di Scienza dei Materiali, Università di Milano Bicocca, Via Cozzi 53, 20125 Milano (Italy); De Michielis, M. [Laboratorio MDM, CNR-IMM, Via C. Olivetti 2, 20864 Agrate Brianza (MB) (Italy); Mazzeo, G.; Fanciulli, M. [Laboratorio MDM, CNR-IMM, Via C. Olivetti 2, 20864 Agrate Brianza (MB) (Italy); Dipartimento di Scienza dei Materiali, Università di Milano Bicocca, Via Cozzi 53, 20125 Milano (Italy); Prati, E. [Laboratorio MDM, CNR-IMM, Via C. Olivetti 2, 20864 Agrate Brianza (MB) (Italy); Istituto di Fotonica e Nanotecnologie, CNR, Piazza Leonardo da Vinci 32, 20133 Milano (Italy)

2016-03-11

We report on the fabrication and the characterization of a tunable complementary-metal oxide semiconductor (CMOS) system consisting of two quantum dots and a MOS single electron transistor (MOSSET) charge sensor. By exploiting a compact T-shaped design and few gates fabricated by electron beam lithography, the MOSSET senses the charge state of either a single or double quantum dot at 4.2 K. The CMOS compatible fabrication process, the simplified control over the number of quantum dots and the scalable geometry make such architecture exploitable for large scale fabrication of multiple spin-based qubits in circuital quantum information processing. - Highlights: • Charge sensing of tunable, by position and number, quantum dots is demonstrated. • A compact T-shaped design with five gates at a single metalization level is proposed. • The electrometer is a silicon-etched nanowire acting as a disorder tolerant MOSSET.

Space Charge Modulated Electrical Breakdown of Oil Impregnated Paper Insulation Subjected to AC-DC Combined Voltages

Directory of Open Access Journals (Sweden)

Yuanwei Zhu

2018-06-01

Full Text Available Based on the existing acknowledgment that space charge modulates AC and DC breakdown of insulating materials, this investigation promotes the related investigation into the situations of more complex electrical stress, i.e., AC-DC combined voltages. Experimentally, the AC-DC breakdown characteristics of oil impregnated paper insulation were systematically investigated. The effects of pre-applied voltage waveform, AC component ratio, and sample thickness on AC-DC breakdown characteristics were analyzed. After that, based on an improved bipolar charge transport model, the space charge profiles and the space charge induced electric field distortion during AC-DC breakdown were numerically simulated to explain the differences in breakdown characteristics between the pre-applied AC and pre-applied DC methods under AC-DC combined voltages. It is concluded that large amounts of homo-charges are accumulated during AC-DC breakdown, which results in significantly distorted inner electric field, leading to variations of breakdown characteristics of oil impregnated paper insulation. Therefore, space charges under AC-DC combined voltages must be considered in the design of converter transformers. In addition, this investigation could provide supporting breakdown data for insulation design of converter transformers and could promote better understanding on the breakdown mechanism of insulating materials subjected to AC-DC combined voltages.

PATH: a lumped-element beam-transport simulation program with space charge

International Nuclear Information System (INIS)

Farrell, J.A.

1983-01-01

PATH is a group of computer programs for simulating charged-particle beam-transport systems. It was developed for evaluating the effects of some aberrations without a time-consuming integration of trajectories through the system. The beam-transport portion of PATH is derived from the well-known program, DECAY TURTLE. PATH contains all features available in DECAY TURTLE (including the input format) plus additional features such as a more flexible random-ray generator, longitudinal phase space, some additional beamline elements, and space-charge routines. One of the programs also provides a simulation of an Alvarez linear accelerator. The programs, originally written for a CDC 7600 computer system, also are available on a VAX-VMS system. All of the programs are interactive with input prompting for ease of use

Numerical Study of Three Dimensional Effects in Longitudinal Space-Charge Impedance

Energy Technology Data Exchange (ETDEWEB)

Halavanau, A. [NICADD, DeKalb; Piot, P. [NICADD, DeKalb

2015-06-01

Longitudinal space-charge (LSC) effects are generally considered as detrimental in free-electron lasers as they can seed instabilities. Such “microbunching instabilities” were recently shown to be potentially useful to support the generation of broadband coherent radiation pulses [1, 2]. Therefore there has been an increasing interest in devising accelerator beamlines capable of sustaining this LSC instability as a mechanism to produce a coherent light source. To date most of these studies have been carried out with a one-dimensional impedance model for the LSC. In this paper we use a N-body “Barnes-Hut” algorithm [3] to simulate the 3D space charge force in the beam combined with elegant [4] and explore the limitation of the 1D model often used

SNS accumulator ring design and space charge considerations

International Nuclear Information System (INIS)

Weng, W.T.

1998-01-01

The goal of the proposed Spallation Neutron Source (SNS) is to provide a short pulse proton beam of about 0.5micros with average beam power of 1MW. To achieve such purpose, a proton storage ring operated at 60Hz with 1 x 10 14 protons per pulse at 1GeV is required. The Accumulator Ring (AR) receives 1msec long H - beam bunches of 28mA from a 1GeV linac. Scope and design performance goals of the AR are presented. About 1,200 turns of charge exchange injection is needed to accumulate 1mA in the ring. After a brief description of the lattice design and machine performance parameters, space charge related issues, such as: tune shifts, stopband corrections, halo generation and beam collimation etc. is discussed

Metal nanoparticle mediated space charge and its optical control in an organic hole-only device

International Nuclear Information System (INIS)

Ligorio, G.; Nardi, M. V.; Steyrleuthner, R.; Neher, D.; Ihiawakrim, D.; Crespo-Monteiro, N.; Brinkmann, M.; Koch, N.

2016-01-01

We reveal the role of localized space charges in hole-only devices based on an organic semiconductor with embedded metal nanoparticles (MNPs). MNPs act as deep traps for holes and reduce the current density compared to a device without MNPs by a factor of 10 4 due to the build-up of localized space charge. Dynamic MNPs charged neutrality can be realized during operation by electron transfer from excitons created in the organic matrix, enabling light sensing independent of device bias. In contrast to the previous speculations, electrical bistability in such devices was not observed.

Imaging space charge regions in Sm-doped ceria using electrochemical strain microscopy

International Nuclear Information System (INIS)

Chen, Qian Nataly; Li, Jiangyu; Adler, Stuart B.

2014-01-01

Nanocrystalline ceria exhibits a total conductivity several orders of magnitude higher than microcrystalline ceria in air at high temperature. The most widely accepted theory for this enhancement (based on fitting of conductivity data to various transport and kinetic models) is that relatively immobile positively charged defects and/or impurities accumulate at the grain boundary core, leading to a counterbalancing increase in the number of mobile electrons (small polarons) within a diffuse space charge region adjacent to each grain boundary. In an effort to validate this model, we have applied electrochemical strain microscopy to image the location and relative population of mobile electrons near grain boundaries in polycrystalline Sm-doped ceria in air at 20–200 °C. Our results show the first direct (spatially resolved) evidence that such a diffuse space charge region does exist in ceria, and is localized to both grain boundaries and the gas-exposed surface

Imaging space charge regions in Sm-doped ceria using electrochemical strain microscopy

Energy Technology Data Exchange (ETDEWEB)

Chen, Qian Nataly; Li, Jiangyu, E-mail: jjli@uw.edu [Department of Mechanical Engineering, University of Washington, Seattle, Washington 98195 (United States); Adler, Stuart B., E-mail: stuadler@uw.edu [Department of Chemical Engineering, University of Washington, Seattle, Washington 98195 (United States)

2014-11-17

Nanocrystalline ceria exhibits a total conductivity several orders of magnitude higher than microcrystalline ceria in air at high temperature. The most widely accepted theory for this enhancement (based on fitting of conductivity data to various transport and kinetic models) is that relatively immobile positively charged defects and/or impurities accumulate at the grain boundary core, leading to a counterbalancing increase in the number of mobile electrons (small polarons) within a diffuse space charge region adjacent to each grain boundary. In an effort to validate this model, we have applied electrochemical strain microscopy to image the location and relative population of mobile electrons near grain boundaries in polycrystalline Sm-doped ceria in air at 20–200 °C. Our results show the first direct (spatially resolved) evidence that such a diffuse space charge region does exist in ceria, and is localized to both grain boundaries and the gas-exposed surface.

Fast neutron detection using a new pulse shape discrimination technique: Charge sensitive integration

International Nuclear Information System (INIS)

Zucker, M.; Tsoupas, N.; Karwowski, H.; Castaneda, C.; Nimnual, S.; Porter, R.; Ward, T.

1988-01-01

A new electronic technique that depends on charge sensitive integration (CSI) has been developed and tested using a CAMAC based pulse shape discrimination system. Neutrons are well separated from γ-ray signals in the 0.1-100 MeV energy range. The new method was compared with the old zero-crossing time-to-amplitude differentiating technique and was found to be comparable in count rate and superior in noise suppression

SPACE CHARGE SIMULATION METHODS INCORPORATED IN SOME MULTI - PARTICLE TRACKING CODES AND THEIR RESULTS COMPARISON

International Nuclear Information System (INIS)

BEEBE - WANG, J.; LUCCIO, A.U.; D IMPERIO, N.; MACHIDA, S.

2002-01-01

Space charge in high intensity beams is an important issue in accelerator physics. Due to the complicity of the problems, the most effective way of investigating its effect is by computer simulations. In the resent years, many space charge simulation methods have been developed and incorporated in various 2D or 3D multi-particle-tracking codes. It has becoming necessary to benchmark these methods against each other, and against experimental results. As a part of global effort, we present our initial comparison of the space charge methods incorporated in simulation codes ORBIT++, ORBIT and SIMPSONS. In this paper, the methods included in these codes are overviewed. The simulation results are presented and compared. Finally, from this study, the advantages and disadvantages of each method are discussed

SPACE CHARGE SIMULATION METHODS INCORPORATED IN SOME MULTI - PARTICLE TRACKING CODES AND THEIR RESULTS COMPARISON.

Energy Technology Data Exchange (ETDEWEB)

BEEBE - WANG,J.; LUCCIO,A.U.; D IMPERIO,N.; MACHIDA,S.

2002-06-03

Space charge in high intensity beams is an important issue in accelerator physics. Due to the complicity of the problems, the most effective way of investigating its effect is by computer simulations. In the resent years, many space charge simulation methods have been developed and incorporated in various 2D or 3D multi-particle-tracking codes. It has becoming necessary to benchmark these methods against each other, and against experimental results. As a part of global effort, we present our initial comparison of the space charge methods incorporated in simulation codes ORBIT++, ORBIT and SIMPSONS. In this paper, the methods included in these codes are overviewed. The simulation results are presented and compared. Finally, from this study, the advantages and disadvantages of each method are discussed.

A feasibility study of space-charge neutralized ion induction linacs: Final report

International Nuclear Information System (INIS)

Slutz, S.A.; Primm, P.; Renk, T.; Johnson, D.J.

1997-03-01

Applications for high current (> 1 kA) ion beams are increasing. They include hardening of material surfaces, transmutation of radioactive waste, cancer treatment, and possibly driving fusion reactions to create energy. The space-charge of ions limits the current that can be accelerated in a conventional ion linear accelerator (linac). Furthermore, the accelerating electric field must be kept low enough to avoid the generation and acceleration of counter-streaming electrons. These limitations have resulted in ion accelerator designs that employ long beam lines and would be expensive to build. Space-charge neutralization and magnetic insulation of the acceleration gaps could substantially reduce these two limitations, but at the expense of increasing the complexity of the beam physics. We present theory and experiments to determine the degree of charge-neutralization that can be achieved in various environments found in ion accelerators. Our results suggest that, for high current applications, space-charge neutralization could be used to improve on the conventional ion accelerator technology. There are two basic magnetic field geometries that can be used to insulate the accelerating gaps, a radial field or a cusp field. We will present studies related to both of these geometries. We shall also present numerical simulations of open-quotes multicuspclose quotes accelerator that would deliver potassium ions at 400 MeV with a total beam power of approximately 40 TW. Such an accelerator could be used to drive fusion

Space Charge Compensation in the Linac4 Low Energy Beam Transport Line with Negative Hydrogen Ions

CERN Document Server

Valerio-Lizarraga, C; Leon-Monzon, I; Lettry, J; Midttun, O; Scrivens, R

2014-01-01

The space charge effect of low energy, unbunched ion beams can be compensated by the trapping of ions or electrons into the beam potential. This has been studied for the 45 keV negative hydrogen ion beam in the CERN Linac4 Low Energy Beam Tranport (LEBT) using the package IBSimu1, which allows the space charge calculation of the particle trajectories. The results of the beam simulations will be compared to emittance measurements of an H- beam at the CERN Linac4 3 MeV test stand, where the injection of hydrogen gas directly into the beam transport region has been used to modify the space charge compensation degree.

Vacuum space charge effects in sub-picosecond soft X-ray photoemission on a molecular adsorbate layer.

Science.gov (United States)

Dell'Angela, M; Anniyev, T; Beye, M; Coffee, R; Föhlisch, A; Gladh, J; Kaya, S; Katayama, T; Krupin, O; Nilsson, A; Nordlund, D; Schlotter, W F; Sellberg, J A; Sorgenfrei, F; Turner, J J; Öström, H; Ogasawara, H; Wolf, M; Wurth, W

2015-03-01

Vacuum space charge induced kinetic energy shifts of O 1s and Ru 3d core levels in femtosecond soft X-ray photoemission spectra (PES) have been studied at a free electron laser (FEL) for an oxygen layer on Ru(0001). We fully reproduced the measurements by simulating the in-vacuum expansion of the photoelectrons and demonstrate the space charge contribution of the high-order harmonics in the FEL beam. Employing the same analysis for 400 nm pump-X-ray probe PES, we can disentangle the delay dependent Ru 3d energy shifts into effects induced by space charge and by lattice heating from the femtosecond pump pulse.

A multigrid based 3D space-charge routine in the tracking code GPT

NARCIS (Netherlands)

Pöplau, G.; Rienen, van U.; Loos, de M.J.; Geer, van der S.B.; Berz, M.; Makino, K.

2005-01-01

Fast calculation of3D non-linear space-charge fields is essential for the simulation ofhigh-brightness charged particle beams. We report on our development of a new 3D spacecharge routine in the General Particle Tracer (GPT) code. The model is based on a nonequidistant multigrid Poisson solver that

Modulating the line shape of magnetoconductance by varying the charge injection in polymer light-emitting diodes

Directory of Open Access Journals (Sweden)

Nidya Chitraningrum

2018-02-01

Full Text Available We fabricate the phenyl-substituted poly(p-phenylene vinylene copolymer (super yellow, SY-PPV-based polymer light-emitting diodes (PLEDs with different device architectures to modulate the injection of opposite charge carriers and investigate the corresponding magnetoconductance (MC responses. At the first glance, we find that all PLEDs exhibit the positive MC responses. By applying the mathematical analysis to fit the curves with two empirical equations of a non-Lorentzian and a Lorentzian function, we are able to extract the hidden negative MC component from the positive MC curve. We attribute the growth of the negative MC component to the reduced interaction of the triplet excitons with charges to generate the free charge carriers as modulated by the applied magnetic field, known as the triplet exciton-charge reaction, by analyzing MC responses for PLEDs of the charge-unbalanced and hole-blocking device configurations. The negative MC component causes the broadening of the line shape in MC curves.

Injection space charge: enlargements of flux density functioning point choice

International Nuclear Information System (INIS)

Ropert, A.

In Saturne, injection consists of a synchrobetatron filling of the chamber, with the goal of providing a beam with the following characteristics circulating in the machine: horizontal flux density 90 πmm mrd, vertical flux density 210 πmm mrd, dispersion in moments +- 7 x 10 -3 , and number of particles 2 x 10 12 . The determination of the principal injection parameters was made by means of GOC calculation programs. The goal of this study is to show a certain number of phenomena induced by the forces due to space charge and left suspended up to this point: variations in the intensity injectable into the machine extension of the beam occupation zone in the ν/sub x'/ ν/sub z/ diagram, and turn-turn interactions. The effects of the space charge lead to a deterioration of the injected beam for certain functioning points leading to the selection of a zone in the ν/sub x'/ ν/sub z/ diagram that is particularly suitable for beam injection

SNS accumulator ring design and space charge considerations

Energy Technology Data Exchange (ETDEWEB)

Weng, W.T.

1998-08-01

The goal of the proposed Spallation Neutron Source (SNS) is to provide a short pulse proton beam of about 0.5 {micro}s with average beam power of 1 MW. To achieve such purpose, a proton storage ring operated at 60 Hz with 1 {times} 10{sup 14} protons per pulse at 1 GeV is required. The Accumulator Ring (AR) receives 1 msec long H{sup {minus}} beam bunches of 28 mA from a 1 GeV linac. Scope and design performance goals of the AR are presented. About 1,200 turns of charge exchange injection is needed to accumulate 1 mA in the ring. After a brief description of the lattice design and machine performance parameters, space charge related issues, such as: tune shifts, stopband corrections, halo generatino and beam collimation etc. is discussed.

SNS ACCUMULATOR RING DESIGN AND SPACE CHARGE CONSIDERATIONS

Energy Technology Data Exchange (ETDEWEB)

WENG,W.T.

1998-05-04

The goal of the proposed Spallation Neutron Source (SNS) is to provide a short pulse proton beam of about 0.5{micro}s with average beam power of 1MW. To achieve such purpose, a proton storage ring operated at 60Hz with 1 x 10{sup 14} protons per pulse at 1GeV is required. The Accumulator Ring (AR) receives 1msec long H{sup {minus}} beam bunches of 28mA from a 1GeV linac. Scope and design performance goals of the AR are presented. About 1,200 turns of charge exchange injection is needed to accumulate 1mA in the ring. After a brief description of the lattice design and machine performance parameters, space charge related issues, such as: tune shifts, stopband corrections, halo generation and beam collimation etc. is discussed.

Metal nanoparticle mediated space charge and its optical control in an organic hole-only device

Energy Technology Data Exchange (ETDEWEB)

Ligorio, G.; Nardi, M. V. [Institut für Physik & IRIS Adlershof, Humboldt-Universität zu Berlin, Brook-Taylor Str. 6, 12489 Berlin (Germany); Steyrleuthner, R.; Neher, D. [Institute of Physics and Astronomy, Universität Potsdam, Karl-Liebknecht Str. 24, 14476 Potsdam (Germany); Ihiawakrim, D. [Institut de Physique et de Chimie des Matériaux de Strasbourg, Université de Strasbourg, CNRS UMR 7504, 23 rue du Loess, BP 43, 67034 Strasbourg, Cedex2 (France); Crespo-Monteiro, N.; Brinkmann, M. [Institut Charles Sadron CNRS, 23 rue du Loess, 67034 Strasbourg (France); Koch, N., E-mail: norbert.koch@physik.hu-berlin.de [Institut für Physik & IRIS Adlershof, Humboldt-Universität zu Berlin, Brook-Taylor Str. 6, 12489 Berlin (Germany); Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Erneuerbare Energien, Albert-Einstein Str. 15, 12489 Berlin (Germany)

2016-04-11

We reveal the role of localized space charges in hole-only devices based on an organic semiconductor with embedded metal nanoparticles (MNPs). MNPs act as deep traps for holes and reduce the current density compared to a device without MNPs by a factor of 10{sup 4} due to the build-up of localized space charge. Dynamic MNPs charged neutrality can be realized during operation by electron transfer from excitons created in the organic matrix, enabling light sensing independent of device bias. In contrast to the previous speculations, electrical bistability in such devices was not observed.

Numerical design of electron guns and space charge limited transport systems

International Nuclear Information System (INIS)

Herrmannsfeldt, W.B.

1980-10-01

This paper describes the capabilities and limitations of computer programs used to design electron guns and similarly space-charge limited transport systems. Examples of computer generated plots from several different types of gun problems are included

Halo and space charge issues in the SNS Ring

International Nuclear Information System (INIS)

Fedotov, A.V.; Abell, D.T.; Beebe-Wang, J.; Lee, Y.Y.; Malitsky, N.; Wei, J.; Gluckstern, R.L.

2000-01-01

The latest designs for high-intensity proton rings require minimizing beam-induced radioactivation of the vacuum chamber. Although the tune depression in the ring is much smaller than in high-intensity linacs, space-charge contributions to halo formation and, hence, beam loss may be significant. This paper reviews our current understanding of halo formation issues for the Spallation Neutron Source (SNS) accumulator ring

Halo and space charge issues in the SNS Ring

Energy Technology Data Exchange (ETDEWEB)

Fedotov, A.V.; Abell, D.T.; Beebe-Wang, J.; Lee, Y.Y.; Malitsky, N.; Wei, J.; Gluckstern, R.L.

2000-06-30

The latest designs for high-intensity proton rings require minimizing beam-induced radioactivation of the vacuum chamber. Although the tune depression in the ring is much smaller than in high-intensity linacs, space-charge contributions to halo formation and, hence, beam loss may be significant. This paper reviews our current understanding of halo formation issues for the Spallation Neutron Source (SNS) accumulator ring.

Development and Application of a Wireless Sensor for Space Charge Density Measurement in an Ultra-High-Voltage, Direct-Current Environment.

Science.gov (United States)

Xin, Encheng; Ju, Yong; Yuan, Haiwen

2016-10-20

A space charge density wireless measurement system based on the idea of distributed measurement is proposed for collecting and monitoring the space charge density in an ultra-high-voltage direct-current (UHVDC) environment. The proposed system architecture is composed of a number of wireless nodes connected with space charge density sensors and a base station. The space charge density sensor based on atmospheric ion counter method is elaborated and developed, and the ARM microprocessor and Zigbee radio frequency module are applied. The wireless network communication quality and the relationship between energy consumption and transmission distance in the complicated electromagnetic environment is tested. Based on the experimental results, the proposed measurement system demonstrates that it can adapt to the complex electromagnetic environment under the UHVDC transmission lines and can accurately measure the space charge density.

Ion trajectories calculation in a three dimensional beam subjected to a space charge

International Nuclear Information System (INIS)

Tauth, T.

1978-04-01

Physical and geometrical conditions allowing a first approximation of necessary sizes to numerical integration of the ions movement equations subjected to electrical and magnetic crossed fields and space charge action are investigated here. To take into consideration the effect of the last one, two artifices are put forward: replacing charged particles by equivalent particles in calculating the coulomb force, electrical field calculation produced in different points situated on the beam envelope by the uniform charges distribution [fr

Phase space properties of charged fields in theories of local observables

International Nuclear Information System (INIS)

Buchholz, D.; D'Antoni, C.

1994-10-01

Within the setting of algebraic quantum field theory a relation between phase-space properties of observables and charged fields is established. These properties are expressed in terms of compactness and nuclarity conditions which are the basis for the characterization of theories with physically reasonable causal and thermal features. Relevant concepts and results of phase space analysis in algebraic qunatum field theory are reviewed and the underlying ideas are outlined. (orig.)

Charge retention test experiences on Hubble Space Telescope nickel-hydrogen battery cells

Science.gov (United States)

Nawrocki, Dave E.; Driscoll, J. R.; Armantrout, J. D.; Baker, R. C.; Wajsgras, H.

1993-01-01

The Hubble Space Telescope (HST) nickel-hydrogen battery module was designed by Lockheed Missile & Space Co (LMSC) and manufactured by Eagle-Picher Ind. (EPI) for the Marshall Space Flight Center (MSFC) as an Orbital Replacement Unit (ORU) for the nickel-cadmium batteries originally selected for this low earth orbit mission. The design features of the HST nickel hydrogen battery are described and the results of an extended charge retention test are summarized.

Numerical analysis of ion wind flow using space charge for optimal design

Science.gov (United States)

Ko, Han Seo; Shin, Dong Ho; Baek, Soo Hong

2014-11-01

Ion wind flow has been widly studied for its advantages of a micro fluidic device. However, it is very difficult to predict the performance of the ion wind flow for various conditions because of its complicated electrohydrodynamic phenomena. Thus, a reliable numerical modeling is required to design an otimal ion wind generator and calculate velocity of the ion wind for the proper performance. In this study, the numerical modeling of the ion wind has been modified and newly defined to calculate the veloctiy of the ion wind flow by combining three basic models such as electrostatics, electrodynamics and fluid dynamics. The model has included presence of initial space charges to calculate transfer energy between space charges and air gas molecules using a developed space charge correlation. The simulation has been performed for a geometry of a pin to parallel plate electrode. Finally, the results of the simulation have been compared with the experimental data for the ion wind velocity to confirm the accuracy of the modified numerical modeling and to obtain the optimal design of the ion wind generator. This work was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Korean government (MEST) (No. 2013R1A2A2A01068653).

Space charge effects and aberrations on electron pulse compression in a spherical electrostatic capacitor.

Science.gov (United States)

Yu, Lei; Li, Haibo; Wan, Weishi; Wei, Zheng; Grzelakowski, Krzysztof P; Tromp, Rudolf M; Tang, Wen-Xin

2017-12-01

The effects of space charge, aberrations and relativity on temporal compression are investigated for a compact spherical electrostatic capacitor (α-SDA). By employing the three-dimensional (3D) field simulation and the 3D space charge model based on numerical General Particle Tracer and SIMION, we map the compression efficiency for a wide range of initial beam size and single-pulse electron number and determine the optimum conditions of electron pulses for the most effective compression. The results demonstrate that both space charge effects and aberrations prevent the compression of electron pulses into the sub-ps region if the electron number and the beam size are not properly optimized. Our results suggest that α-SDA is an effective compression approach for electron pulses under the optimum conditions. It may serve as a potential key component in designing future time-resolved electron sources for electron diffraction and spectroscopy experiments. Copyright © 2017 Elsevier B.V. All rights reserved.

A space-charge treatment of the increased concentration of reactive species at the surface of a ceria solid solution

Energy Technology Data Exchange (ETDEWEB)

Zurhelle, Alexander F.; Souza, Roger A. de [Institute of Physical Chemistry, RWTH Aachen University (Germany); Tong, Xiaorui; Mebane, David S. [Department of Mechanical and Aerospace Engineering, West Virginia University, Morgantown, WV (United States); Klein, Andreas [Institute of Materials Science, TU Darmstadt (Germany)

2017-11-13

A space-charge theory applicable to concentrated solid solutions (Poisson-Cahn theory) was applied to describe quantitatively as a function of temperature and oxygen partial pressure published data obtained by in situ X-ray photoelectron spectroscopy (XPS) for the concentration of Ce{sup 3+} (the reactive species) at the surface of the oxide catalyst Ce{sub 0.8}Sm{sub 0.2}O{sub 1.9}. In contrast to previous theoretical treatments, these calculations clearly indicate that the surface is positively charged and compensated by an attendant negative space-charge zone. The high space-charge potential that develops at the surface (>0.8 V) is demonstrated to be hardly detectable by XPS measurements because of the short extent of the space-charge layer. This approach emphasizes the need to take into account defect interactions and to allow deviations from local charge neutrality when considering the surfaces of oxide catalysts. (copyright 2017 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

Phase space imaging of a beam of charged particles by frictional forces

International Nuclear Information System (INIS)

Daniel, H.

1977-01-01

In the case of frictional forces, defined by always acting opposite to the particle motion, Liouville's theorem does not apply. The effect of such forces on a beam of charged particles is calculated in closed form. Emphasis is given to the phase space imaging by a moderator. Conditions for an increase in phase space density are discussed. (Auth.)

An FPGA computing demo core for space charge simulation

International Nuclear Information System (INIS)

Wu, Jinyuan; Huang, Yifei

2009-01-01

In accelerator physics, space charge simulation requires large amount of computing power. In a particle system, each calculation requires time/resource consuming operations such as multiplications, divisions, and square roots. Because of the flexibility of field programmable gate arrays (FPGAs), we implemented this task with efficient use of the available computing resources and completely eliminated non-calculating operations that are indispensable in regular micro-processors (e.g. instruction fetch, instruction decoding, etc.). We designed and tested a 16-bit demo core for computing Coulomb's force in an Altera Cyclone II FPGA device. To save resources, the inverse square-root cube operation in our design is computed using a memory look-up table addressed with nine to ten most significant non-zero bits. At 200 MHz internal clock, our demo core reaches a throughput of 200 M pairs/s/core, faster than a typical 2 GHz micro-processor by about a factor of 10. Temperature and power consumption of FPGAs were also lower than those of micro-processors. Fast and convenient, FPGAs can serve as alternatives to time-consuming micro-processors for space charge simulation.

An FPGA computing demo core for space charge simulation

Energy Technology Data Exchange (ETDEWEB)

Wu, Jinyuan; Huang, Yifei; /Fermilab

2009-01-01

In accelerator physics, space charge simulation requires large amount of computing power. In a particle system, each calculation requires time/resource consuming operations such as multiplications, divisions, and square roots. Because of the flexibility of field programmable gate arrays (FPGAs), we implemented this task with efficient use of the available computing resources and completely eliminated non-calculating operations that are indispensable in regular micro-processors (e.g. instruction fetch, instruction decoding, etc.). We designed and tested a 16-bit demo core for computing Coulomb's force in an Altera Cyclone II FPGA device. To save resources, the inverse square-root cube operation in our design is computed using a memory look-up table addressed with nine to ten most significant non-zero bits. At 200 MHz internal clock, our demo core reaches a throughput of 200 M pairs/s/core, faster than a typical 2 GHz micro-processor by about a factor of 10. Temperature and power consumption of FPGAs were also lower than those of micro-processors. Fast and convenient, FPGAs can serve as alternatives to time-consuming micro-processors for space charge simulation.

Parametric Landau damping of space charge modes

Energy Technology Data Exchange (ETDEWEB)

Macridin, Alexandru [Fermilab; Burov, Alexey [Fermilab; Stern, Eric [Fermilab; Amundson, James [Fermilab; Spentzouris, Panagiotis [Fermilab

2016-09-23

Landau damping is the mechanism of plasma and beam stabilization; it arises through energy transfer from collective modes to the incoherent motion of resonant particles. Normally this resonance requires the resonant particle's frequency to match the collective mode frequency. We have identified an important new damping mechanism, parametric Landau damping, which is driven by the modulation of the mode-particle interaction. This opens new possibilities for stability control through manipulation of both particle and mode-particle coupling spectra. We demonstrate the existence of parametric Landau damping in a simulation of transverse coherent modes of bunched accelerator beams with space charge.

Performance of carbon fiber reinforced rubber composite armour against shaped charge jet penetration

OpenAIRE

Yue Lian-yong; Li Wei; Zu Xu-dong; Huang Zheng-xiang; Gao Zhen-yu

2016-01-01

Natural rubber is reinforced with carbon fiber; the protective performances of the carbonfiber reinforced rubber composite armour to shaped charge jet have been studied based on the depth of penetration experiments. The craters on the witness blocks, the nature rubber based composite plates’ deformation and the Scanning Electron Microscopy for the hybrid fiber reinforced rubber plate also is analyzed. The results showed that the composite armour can affect the stability of the jet and made pa...

Shape-Tunable Charge Carrier Dynamics at the Interfaces between Perovskite Nanocrystals and Molecular Acceptors

KAUST Repository

Ahmed, Ghada H.

2016-09-19

Hybrid organic/inorganic perovskites have recently emerged as an important class of materials and have exhibited remarkable performance in photovoltaics. To further improve their device efficiency, an insightful understanding of the interfacial charge transfer (CT) process is required. Here, we report the first direct experimental observation of the tremendous effect that the shape of perovskite nanocrystals (NCs) has on interfacial CT in the presence of a molecular acceptor. A dramatic change in CT dynamics at the interfaces of three different NC shapes, spheres, platelets, and cubes, is recorded. Our results clearly demonstrate that the mechanism of CT is significantly affected by the NC shape. More importantly, the results demonstrate that complexation on the NC surface acts as an additional driving force not only to tune the CT dynamics but also to control the reaction mechanism at the interface. This observation opens a new venue for further developing perovskite NCs-based applications.

Shape-Tunable Charge Carrier Dynamics at the Interfaces between Perovskite Nanocrystals and Molecular Acceptors

KAUST Repository

Ahmed, Ghada H.; Liu, Jiakai; Parida, Manas R.; Banavoth, Murali; Bose, Riya; AlYami, Noktan; Hedhili, Mohamed N.; Peng, Wei; Pan, Jun; Besong, Tabot M.D.; Bakr, Osman; Mohammed, Omar F.

2016-01-01

Hybrid organic/inorganic perovskites have recently emerged as an important class of materials and have exhibited remarkable performance in photovoltaics. To further improve their device efficiency, an insightful understanding of the interfacial charge transfer (CT) process is required. Here, we report the first direct experimental observation of the tremendous effect that the shape of perovskite nanocrystals (NCs) has on interfacial CT in the presence of a molecular acceptor. A dramatic change in CT dynamics at the interfaces of three different NC shapes, spheres, platelets, and cubes, is recorded. Our results clearly demonstrate that the mechanism of CT is significantly affected by the NC shape. More importantly, the results demonstrate that complexation on the NC surface acts as an additional driving force not only to tune the CT dynamics but also to control the reaction mechanism at the interface. This observation opens a new venue for further developing perovskite NCs-based applications.

Numerical investigation of space charge electric field for a sheet ...

Indian Academy of Sciences (India)

One of the problems in scaling high power vacuum and plasma microwave sources to higher frequencies is the need to transport beams with higher space charge density, since the radio frequency circuit transverse dimensions tend to decrease with wavelength. The use of sheet electron beams can alleviate this difficulty ...

Spectral investigation of a complex space charge structure in plasma

International Nuclear Information System (INIS)

Gurlui, S.; Dimitriu, D. G.; Ionita, C.; Schrittwieser, R. W.

2009-01-01

Complex space charge structures bordered by electrical double layers were spectrally investigated in argon plasma in the domain 400-1000 nm, identifying the lines corresponding to the transitions from different excited states of argon. The electron excitation temperature in the argon atoms was estimated from the spectral lines intensity ratio. (authors)

Second order elastic metrics on the shape space of curves

DEFF Research Database (Denmark)

Bauer, Martin; Bruveris, Martins; Harms, Philipp

2015-01-01

Second order Sobolev metrics on the space of regular unparametrized planar curves have several desirable completeness properties not present in lower order metrics, but numerics are still largely missing. In this paper, we present algorithms to numerically solve the initial and boundary value......, due to its generality, it could be applied to more general spaces of mapping. We demonstrate the effectiveness of our approach by analyzing a collection of shapes representing physical objects....

Bulk-Like Electrical Properties Induced by Contact-Limited Charge Transport in Organic Diodes: Revised Space Charge Limited Current

KAUST Repository

Xu, Guangwei

2018-02-22

Charge transport governs the operation and performance of organic diodes. Illuminating the charge-transfer/transport processes across the interfaces and the bulk organic semiconductors is at the focus of intensive investigations. Traditionally, the charge transport properties of organic diodes are usually characterized by probing the current–voltage (I–V) curves of the devices. However, to unveil the landscape of the underlying potential/charge distribution, which essentially determines the I–V characteristics, still represents a major challenge. Here, the electrical potential distribution in planar organic diodes is investigated by using the scanning Kelvin probe force microscopy technique, a method that can clearly separate the contact and bulk regimes of charge transport. Interestingly, by applying to devices based on novel, high mobility organic materials, the space-charge-limited-current-like I–V curves, which are previously believed to be a result of the bulk transport, are surprisingly but unambiguously demonstrated to be caused by contact-limited conduction. A model accounting is developed for the transport properties of both the two metal/organic interfaces and the bulk. The results indicate that pure interface-dominated transport can indeed give rise to I–V curves similar to those caused by bulk transport. These findings provide a new insight into the charge injection and transport processes in organic diodes.

Stability analysis of Hasegawa space-charge waves in a plasma waveguide with collisional ion beam

Science.gov (United States)

Lee, Myoung-Jae; Jung, Young-Dae

2017-12-01

The dispersion relation for the Hasegawa space-charge wave propagating in a cylindrical waveguide dusty plasma containing collision-dominated ion stream is derived by using the fluid equations and the Poisson equation which lead to a Bessel equation. The solution of Bessel equation is null at the boundary and then the roots of the Bessel function would characterize the property of space-charge wave propagation. We have found that the Hasegawa space-charge wave can be excited for a large axial wave number. The growth rate of excitation increases as the order of the roots of the Bessel function increases. The growth rate decreases with an increase of the radius of cylindrical waveguide as well as with an increase of the collision frequency. We found that the disturbance of wave can be damped only for small wave numbers.

Negative differential mobility for negative carriers as revealed by space charge measurements on crosslinked polyethylene insulated model cables

International Nuclear Information System (INIS)

Teyssedre, G.; Laurent, C.; Vu, T. T. N.

2015-01-01

Among features observed in polyethylene materials under relatively high field, space charge packets, consisting in a pulse of net charge that remains in the form of a pulse as it crosses the insulation, are repeatedly observed but without complete theory explaining their formation and propagation. Positive charge packets are more often reported, and the models based on negative differential mobility(NDM) for the transport of holes could account for some charge packets phenomenology. Conversely, NDM for electrons transport has never been reported so far. The present contribution reports space charge measurements by pulsed electroacoustic method on miniature cables that are model of HVDC cables. The measurements were realized at room temperature or with a temperature gradient of 10 °C through the insulation under DC fields on the order 30–60 kV/mm. Space charge results reveal systematic occurrence of a negative front of charges generated at the inner electrode that moves toward the outer electrode at the beginning of the polarization step. It is observed that the transit time of the front of negative charge increases, and therefore the mobility decreases, with the applied voltage. Further, the estimated mobility, in the range 10 −14 –10 −13  m 2  V −1  s −1 for the present results, increases when the temperature increases for the same condition of applied voltage. The features substantiate the hypothesis of negative differential mobility used for modelling space charge packets

Negative differential mobility for negative carriers as revealed by space charge measurements on crosslinked polyethylene insulated model cables

Science.gov (United States)

Teyssedre, G.; Vu, T. T. N.; Laurent, C.

2015-12-01

Among features observed in polyethylene materials under relatively high field, space charge packets, consisting in a pulse of net charge that remains in the form of a pulse as it crosses the insulation, are repeatedly observed but without complete theory explaining their formation and propagation. Positive charge packets are more often reported, and the models based on negative differential mobility(NDM) for the transport of holes could account for some charge packets phenomenology. Conversely, NDM for electrons transport has never been reported so far. The present contribution reports space charge measurements by pulsed electroacoustic method on miniature cables that are model of HVDC cables. The measurements were realized at room temperature or with a temperature gradient of 10 °C through the insulation under DC fields on the order 30-60 kV/mm. Space charge results reveal systematic occurrence of a negative front of charges generated at the inner electrode that moves toward the outer electrode at the beginning of the polarization step. It is observed that the transit time of the front of negative charge increases, and therefore the mobility decreases, with the applied voltage. Further, the estimated mobility, in the range 10-14-10-13 m2 V-1 s-1 for the present results, increases when the temperature increases for the same condition of applied voltage. The features substantiate the hypothesis of negative differential mobility used for modelling space charge packets.

Safety of information in electronic equipment influenced by the charged space particles

Directory of Open Access Journals (Sweden)

Ksenia Gennad’evna Sizova

2016-10-01

Full Text Available A version of the existing evaluation method of electronic equipment to the influence of charged space particles causing single event effects for the purpose of improving the accuracy of calculation in the field of information safety is suggested. On the basis of the existing and modified methods radiation tolerance of real payload spacecraft responsible for the security of transmitted information are defined. The results of comparison are introduced. Significant differences not only in quantitative but also in qualitative character of tolerance indicators are revealed. It is demonstrated that the modified method allows to take into account the functional complexity of the hardware and the application efficiency of the sophisticated single event effects protection tools. To confirm the applicability of the modified method of equipment tolerance evaluation method to the influence of charged space particles causing single event effects proposals to the procedure of ground tests of the payload and the space experiment are developed.

Ewald Electrostatics for Mixtures of Point and Continuous Line Charges.

Science.gov (United States)

Antila, Hanne S; Tassel, Paul R Van; Sammalkorpi, Maria

2015-10-15

Many charged macro- or supramolecular systems, such as DNA, are approximately rod-shaped and, to the lowest order, may be treated as continuous line charges. However, the standard method used to calculate electrostatics in molecular simulation, the Ewald summation, is designed to treat systems of point charges. We extend the Ewald concept to a hybrid system containing both point charges and continuous line charges. We find the calculated force between a point charge and (i) a continuous line charge and (ii) a discrete line charge consisting of uniformly spaced point charges to be numerically equivalent when the separation greatly exceeds the discretization length. At shorter separations, discretization induces deviations in the force and energy, and point charge-point charge correlation effects. Because significant computational savings are also possible, the continuous line charge Ewald method presented here offers the possibility of accurate and efficient electrostatic calculations.

Charged particle identification including Pions by pulse-shape discrimination with an NE213 liquid scintillator

International Nuclear Information System (INIS)

Nakamoto, T.; Ishibashi, K.; Matsufuji, N.; Shigyo, N.; Maehata, K.

1995-01-01

Particles emitted from spallation reactions induced by protons having GeV energies were measured with an NE213 liquid scintillator, 12.7 cm in diameter and 12.7 cm thick. The pulse-shape discrimination (PSD) was carried out for charged particle identification by the two-gate integration method. Pions having energies up to 60 MeV were clearly discriminated from protons and electrons. On the contrary, pions with higher energies could not be identified since they escaped from the detector. The advantage of PSD for charged particle identification is that there is no requirement for a ΔE detector in the measurements. copyright 1995 American Institute of Physics

Space charge compensation in the Linac4 low energy beam transport line with negative hydrogen ions

Energy Technology Data Exchange (ETDEWEB)

Valerio-Lizarraga, Cristhian A., E-mail: cristhian.alfonso.valerio.lizarraga@cern.ch [CERN, Geneva (Switzerland); Departamento de Investigación en Física, Universidad de Sonora, Hermosillo (Mexico); Lallement, Jean-Baptiste; Lettry, Jacques; Scrivens, Richard [CERN, Geneva (Switzerland); Leon-Monzon, Ildefonso [Facultad de Ciencias Fisico-Matematicas, Universidad Autónoma de Sinaloa, Culiacan (Mexico); Midttun, Øystein [CERN, Geneva (Switzerland); University of Oslo, Oslo (Norway)

2014-02-15

The space charge effect of low energy, unbunched ion beams can be compensated by the trapping of ions or electrons into the beam potential. This has been studied for the 45 keV negative hydrogen ion beam in the CERN Linac4 Low Energy Beam Transport using the package IBSimu [T. Kalvas et al., Rev. Sci. Instrum. 81, 02B703 (2010)], which allows the space charge calculation of the particle trajectories. The results of the beam simulations will be compared to emittance measurements of an H{sup −} beam at the CERN Linac4 3 MeV test stand, where the injection of hydrogen gas directly into the beam transport region has been used to modify the space charge compensation degree.

Parallel Finite Element Particle-In-Cell Code for Simulations of Space-charge Dominated Beam-Cavity Interactions

International Nuclear Information System (INIS)

Candel, A.; Kabel, A.; Ko, K.; Lee, L.; Li, Z.; Limborg, C.; Ng, C.; Prudencio, E.; Schussman, G.; Uplenchwar, R.

2007-01-01

Over the past years, SLAC's Advanced Computations Department (ACD) has developed the parallel finite element (FE) particle-in-cell code Pic3P (Pic2P) for simulations of beam-cavity interactions dominated by space-charge effects. As opposed to standard space-charge dominated beam transport codes, which are based on the electrostatic approximation, Pic3P (Pic2P) includes space-charge, retardation and boundary effects as it self-consistently solves the complete set of Maxwell-Lorentz equations using higher-order FE methods on conformal meshes. Use of efficient, large-scale parallel processing allows for the modeling of photoinjectors with unprecedented accuracy, aiding the design and operation of the next-generation of accelerator facilities. Applications to the Linac Coherent Light Source (LCLS) RF gun are presented

Modification of backgammon shape cathode and graded charge division readout method for a novel triple charge division centroid finding method

International Nuclear Information System (INIS)

Javanmardi, F.; Matoba, M.; Sakae, T.

1996-01-01

Triple Charge Division (TCD) centroid finding method that uses modified pattern of Backgammon Shape Cathode (MBSC) is introduced for medium range length position sensitive detectors with optimum numbers of cathode segments. MBSC pattern has three separated areas and uses saw tooth like insulator gaps for separating the areas. Side areas of the MBSC pattern are severed by a central common area. Size of the central area is twice of the size of both sides. Whereas central area is the widest area among three, both sides' areas have the main role in position sensing. With the same resolution and linearity, active region of original Backgammon pattern increases twice by using MBSC pattern, and with the same length, linearity of TCD centroid finding is much better than Backgammon charge division readout method. Linearity prediction of TCD centroid finding and experimental results conducted us to find an optimum truncation of the apices of MBCS pattern in the central area. The TCD centroid finding has an especial readout method since charges must be collected from two segments in both sides and from three segments in the central area of MBSC pattern. The so called Graded Charge Division (GCD) is the especial readout method for TCD. The GCD readout is a combination of the charge division readout and sequence grading of serial segments. Position sensing with TCD centroid finding and GCD readout were done by two sizes MBSC patterns (200mm and 80mm) and Spatial resolution about 1% of the detector length is achieved

Current distribution in triodes neglecting space charge and initial velocities

NARCIS (Netherlands)

Hamaker, H.C.

1950-01-01

A theory of the current distribution in triodes with positive grid is developed on the assumption that space charge and the initial velocities of both primary and secondary electrons may be neglected. This theory, which is originally due to De Lussanct de la Sablonière, has been put in a more lucid

Phase modulation spectroscopy of space-charge wave resonances in Bi12SiO20

DEFF Research Database (Denmark)

Vasnetsov, M.; Buchhave, Preben; Lyuksyutov, S.

1997-01-01

A new experimental method for the study of resonance effects and space-charge wave excitation in photorefractive Bi12SiO20 crystals by using a combination of frequency detuning and phase modulation technique has been developed. The accuracy of the method allows a detection of resonance peaks...... of diffraction efficiency within 0.5 Hz. Numerical simulations of the nonlinear differential equations describing the behaviour of the space-charge waves in photorefractive crystals have been performed and found to be in a good agreement with experiment. We have measured the photocurrent through the crystal...

Chaos in charged AdS black hole extended phase space

Science.gov (United States)

Chabab, M.; El Moumni, H.; Iraoui, S.; Masmar, K.; Zhizeh, S.

2018-06-01

We present an analytical study of chaos in a charged black hole in the extended phase space in the context of the Poincare-Melnikov theory. Along with some background on dynamical systems, we compute the relevant Melnikov function and find its zeros. Then we analyse these zeros either to identify the temporal chaos in the spinodal region, or to observe spatial chaos in the small/large black hole equilibrium configuration. As a byproduct, we derive a constraint on the Black hole' charge required to produce chaotic behaviour. To the best of our knowledge, this is the first endeavour to understand the correlation between chaos and phase picture in black holes.

Relations between focusing power of space-charge lenses and external electromagnetic fields

International Nuclear Information System (INIS)

Yu Qingchang; Qiu Hong; Huang Jiachang

1991-01-01

Under different external electromagnetic fields, the electron densities of the electron cloud in a self-sustaning spece-charge lens are measured with the radio-frequency method and the energy distributions of the ions produced in ionization are measured with the stopping field method. From them the relations between the focusing power of space-charge lenses and the external electromagnetic fields are determined. The available region of the Lebedev-Morozov formula is discussed

Transformers: Shape-Changing Space Systems Built with Robotic Textiles

Science.gov (United States)

Stoica, Adrian

2013-01-01

Prior approaches to transformer-like robots had only very limited success. They suffer from lack of reliability, ability to integrate large surfaces, and very modest change in overall shape. Robots can now be built from two-dimensional (2D) layers of robotic fabric. These transformers, a new kind of robotic space system, are dramatically different from current systems in at least two ways. First, the entire transformer is built from a single, thin sheet; a flexible layer of a robotic fabric (ro-fabric); or robotic textile (ro-textile). Second, the ro-textile layer is foldable to small volume and self-unfolding to adapt shape and function to mission phases.

Space charge compensation on the low energy beam transport of Linac4

CERN Document Server

AUTHOR|(SzGeCERN)733270; Scrivens, Richard; Jesus Castillo, Santos

Part of the upgrade program in the injector chains of the CERN accelerator complex is the replacement of the the proton accelerator Linac2 for the brand new Linac4 which will accelerate H$^-$ and its main goal is to increase the beam intensity in the next sections of the LHC accelerator chain. The Linac4 is now under commissioning and will use several ion sources to produce high intensity unbunched H$^-$ beams with different properties, and the low energy beam transport (LEBT) is the system in charge of match all these different beams to the Radio frequency quadrupole (RFQ). The space charge forces that spread the beam ions apart of each other and cause emittance growth limits the maximum intensity that can be transported in the LEBT, but the space charge of intense unbunched ion beams can be compensated by the generated ions by the impact ionization of the residual gas, which creates a source of secondary particles inside the beam pipe. For negative ion beams, the effect of the beam electric field is to ex...

Aberration of a negative ion beam caused by space charge effect

International Nuclear Information System (INIS)

Miyamoto, K.; Wada, S.; Hatayama, A.

2010-01-01

Aberrations are inevitable when the charged particle beams are extracted, accelerated, transmitted, and focused with electrostatic and magnetic fields. In this study, we investigate the aberration of a negative ion accelerator for a neutral beam injector theoretically, especially the spherical aberration caused by the negative ion beam expansion due to the space charge effect. The negative ion current density profiles with the spherical aberration are compared with those without the spherical aberration. It is found that the negative ion current density profiles in a log scale are tailed due to the spherical aberration.

Aberration of a negative ion beam caused by space charge effect

Energy Technology Data Exchange (ETDEWEB)

Miyamoto, K. [Naruto University of Education, 748 Nakashima, Takashima, Naruto-cho, Naruto-shi, Tokushima 772-8502 (Japan); Wada, S.; Hatayama, A. [Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522 (Japan)

2010-02-15

Aberrations are inevitable when the charged particle beams are extracted, accelerated, transmitted, and focused with electrostatic and magnetic fields. In this study, we investigate the aberration of a negative ion accelerator for a neutral beam injector theoretically, especially the spherical aberration caused by the negative ion beam expansion due to the space charge effect. The negative ion current density profiles with the spherical aberration are compared with those without the spherical aberration. It is found that the negative ion current density profiles in a log scale are tailed due to the spherical aberration.

Aberration of a negative ion beam caused by space charge effect.

Science.gov (United States)

Miyamoto, K; Wada, S; Hatayama, A

2010-02-01

Aberrations are inevitable when the charged particle beams are extracted, accelerated, transmitted, and focused with electrostatic and magnetic fields. In this study, we investigate the aberration of a negative ion accelerator for a neutral beam injector theoretically, especially the spherical aberration caused by the negative ion beam expansion due to the space charge effect. The negative ion current density profiles with the spherical aberration are compared with those without the spherical aberration. It is found that the negative ion current density profiles in a log scale are tailed due to the spherical aberration.

Shape Memory Alloy Cryogenic Transfer Coupling for Space Depot Docking Operations

Data.gov (United States)

National Aeronautics and Space Administration — The technical objective of the proposed effort is to establish the feasibility of using shape memory alloy (SMA) actuators for selected components of the automatic...

Radiation Resistant, Reconfigurable, Shape Memory Metal Rubber Space Arrays, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — NanoSonic has demonstrated that Shape Memory Metal RubberTM (SM-MR) adaptive skins exhibit reconfigurable and durable RF properties. It is hypothesized that such...

Transition from Fowler-Nordheim field emission to space charge limited current density

International Nuclear Information System (INIS)

Feng, Y.; Verboncoeur, J. P.

2006-01-01

The Fowler-Nordheim law gives the current density extracted from a surface under strong fields, by treating the emission of electrons from a metal-vacuum interface in the presence of an electric field normal to the surface as a quantum mechanical tunneling process. Child's law predicts the maximum transmitted current density by considering the space charge effect. When the electric field becomes high enough, the emitted current density will be limited by Child's law. This work analyzes the transition of the transmitted current density from the Fowler-Nordheim law to Child's law space charge limit using a one-dimensional particle-in-cell code. Also studied is the response of the emission model to strong electric fields near the transition point. We find the transition without geometrical effort is smooth and much slower than reported previously [J. P. Barbour, W. W. Dolan, J. K. Trolan, E. E. Martin, and W. P. Dyke, Phys. Rev. 92, 45 (1953)]. We analyze the effects of geometric field enhancement and work function on the transition. Using our previous model for effective field enhancement [Y. Feng and J. P. Verboncoeur, Phys. Plasmas 12, 103301 (2005)], we find the geometric effect dominates, and enhancement β>10 can accelerate the approach to the space charge limit at practical electric field. A damped oscillation near the local plasma frequency is observed in the transient system response

Working Group 2 summary: Space charge effects in bending systems

International Nuclear Information System (INIS)

Bohn, C.L.; Emma, P.J.

2000-01-01

At the start of the Workshop, the authors asked the Working Group 2 participants to concentrate on three basic goals: (1) survey the status of how comprehensively the physics concerning space-charge effects in bends is understood and how complete is the available ensemble of analytic and computational tools; (2) guided by data from experiments and operational experience, identify sources of, and cures for, beam degradation; and (3) review space-charge physics in rings and the limitations it introduces. As the Workshop unfolded, the third goal naturally folded into the other two goals, and these goals, they believe, were fulfilled in that the Working Group was able to compile an end product consisting of a set of recommendations for potentially fruitful future work. This summary constitutes an overview of the deliberations of the Working Group, and it is their hope that the summary clarifies the motivation for the recommended work listed at the end. The summary is organized according to the two aforementioned goals, and the prime topics of discussion appear as subsections under these goals

The space charge effects on the slow extraction process

International Nuclear Information System (INIS)

Ohmori, Chihiro.

1992-06-01

The calculation of the slow extraction which includes the space charge effects has been performed for the Compressor/Stretcher Ring (CSR) of the proposed Japanese Hadron Project. We have investigated the slow extraction of 1 GeV proton beam with an average current of 100μA. Calculation shows not only the emittance growth of the extracted beam but also decrease of the extraction efficiency and discontinuity of beam spill. (author)

Space charge effects for multipactor in coaxial lines

Energy Technology Data Exchange (ETDEWEB)

Sorolla, E., E-mail: eden.sorolla@xlim.fr [XLIM, UMR 7252, Université de Limoges/CNRS, 123 Av. Albert Thomas, 87060 Limoges (France); Sounas, A.; Mattes, M. [Laboratoire d' Électromagnétisme et d' Acoustique (LEMA), École Polytechnique Fédérale de Lausanne, Station 11, CH-1015 Lausanne (Switzerland)

2015-03-15

Multipactor is a hazardous vacuum discharge produced by secondary electron emission within microwave devices of particle accelerators and telecommunication satellites. This work analyzes the dynamics of the multipactor discharge within a coaxial line for the mono-energetic electron emission model taking into account the space charge effects. The steady-state is predicted by the proposed model and an analytical expression for the maximum number of electrons released by the discharge presented. This could help to link simulations to experiments and define a multipactor onset criterion.

Space charge effects for multipactor in coaxial lines

International Nuclear Information System (INIS)

Sorolla, E.; Sounas, A.; Mattes, M.

2015-01-01

Multipactor is a hazardous vacuum discharge produced by secondary electron emission within microwave devices of particle accelerators and telecommunication satellites. This work analyzes the dynamics of the multipactor discharge within a coaxial line for the mono-energetic electron emission model taking into account the space charge effects. The steady-state is predicted by the proposed model and an analytical expression for the maximum number of electrons released by the discharge presented. This could help to link simulations to experiments and define a multipactor onset criterion

Overview of Alternative Bunching and Current-shaping Techniques for Low-Energy Electron Beams

Energy Technology Data Exchange (ETDEWEB)

Piot, Philippe [Northern Illinois U.

2015-12-01

Techniques to bunch or shape an electron beam at low energies (E <15 MeV) have important implications toward the realization of table-top radiation sources [1] or to the design of compact multi-user free-electron lasers[2]. This paper provides an overview of alternative methods recently developed including techniques such as wakefield-based bunching, space-charge-driven microbunching via wave-breaking [3], ab-initio shaping of the electron-emission process [4], and phase space exchangers. Practical applications of some of these methods to foreseen free-electron-laser configurations are also briefly discussed [5].

Negative differential mobility for negative carriers as revealed by space charge measurements on crosslinked polyethylene insulated model cables

Energy Technology Data Exchange (ETDEWEB)

Teyssedre, G., E-mail: gilbert.teyssedre@laplace.univ-tlse.fr; Laurent, C. [Université de Toulouse, UPS, INPT, LAPLACE (Laboratoire Plasma et Conversion d' Energie), 118 route de Narbonne, F-31062 Toulouse cedex 9 (France); CNRS, LAPLACE, F-31062 Toulouse (France); Vu, T. T. N. [Université de Toulouse, UPS, INPT, LAPLACE (Laboratoire Plasma et Conversion d' Energie), 118 route de Narbonne, F-31062 Toulouse cedex 9 (France); Electric Power University, 235 Hoang Quoc Viet, 10000 Hanoi (Viet Nam)

2015-12-21

Among features observed in polyethylene materials under relatively high field, space charge packets, consisting in a pulse of net charge that remains in the form of a pulse as it crosses the insulation, are repeatedly observed but without complete theory explaining their formation and propagation. Positive charge packets are more often reported, and the models based on negative differential mobility(NDM) for the transport of holes could account for some charge packets phenomenology. Conversely, NDM for electrons transport has never been reported so far. The present contribution reports space charge measurements by pulsed electroacoustic method on miniature cables that are model of HVDC cables. The measurements were realized at room temperature or with a temperature gradient of 10 °C through the insulation under DC fields on the order 30–60 kV/mm. Space charge results reveal systematic occurrence of a negative front of charges generated at the inner electrode that moves toward the outer electrode at the beginning of the polarization step. It is observed that the transit time of the front of negative charge increases, and therefore the mobility decreases, with the applied voltage. Further, the estimated mobility, in the range 10{sup −14}–10{sup −13} m{sup 2} V{sup −1} s{sup −1} for the present results, increases when the temperature increases for the same condition of applied voltage. The features substantiate the hypothesis of negative differential mobility used for modelling space charge packets.

Aspects of space charge theory applied to dielectric under electron beam irradiation

International Nuclear Information System (INIS)

Oliveira, L.N. de.

1975-01-01

Irradiation of solid dielectric with electron beams has been used as a power full tool in investigations of charge storage and transport in such materials. Some of the results that have been obtained in this area are reviewed and the formulation of a transport equation for excess charge in irradiated insulators is dicussed. This equation is subsequently applied to various experimental set-ups. It is found that space charge effects play an essential role in the establishment of stationary currents in samples subject to quasi-penetrating electron beams. Such effects may, however, be neglected for low electron ranges. Theoretical results are in good agreement with experimental findings by Spear (1955)

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

Energy Technology Data Exchange (ETDEWEB)

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

2015-11-15

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

Topology and shape optimization of induced-charge electro-osmotic micropumps

DEFF Research Database (Denmark)

Gregersen, Misha Marie; Okkels, Fridolin; Bazant, M. Z.

2009-01-01

For a dielectric solid surrounded by an electrolyte and positioned inside an externally biased parallel-plate capacitor, we study numerically how the resulting induced-charge electro-osmotic (ICEO) flow depends on the topology and shape of the dielectric solid. In particular, we extend existing...... conventional electrokinetic models with an artificial design field to describe the transition from the liquid electrolyte to the solid dielectric. Using this design field, we have succeeded in applying the method of topology optimization to find system geometries with non-trivial topologies that maximize...... the net induced electro-osmotic flow rate through the electrolytic capacitor in the direction parallel to the capacitor plates. Once found, the performance of the topology-optimized geometries has been validated by transferring them to conventional electrokinetic models not relying on the artificial...

Improving radiation hardness in space-based Charge-Coupled Devices through the narrowing of the charge transfer channel

Science.gov (United States)

Hall, D. J.; Skottfelt, J.; Soman, M. R.; Bush, N.; Holland, A.

2017-12-01

Charge-Coupled Devices (CCDs) have been the detector of choice for imaging and spectroscopy in space missions for several decades, such as those being used for the Euclid VIS instrument and baselined for the SMILE SXI. Despite the many positive properties of CCDs, such as the high quantum efficiency and low noise, when used in a space environment the detectors suffer damage from the often-harsh radiation environment. High energy particles can create defects in the silicon lattice which act to trap the signal electrons being transferred through the device, reducing the signal measured and effectively increasing the noise. We can reduce the impact of radiation on the devices through four key methods: increased radiation shielding, device design considerations, optimisation of operating conditions, and image correction. Here, we concentrate on device design operations, investigating the impact of narrowing the charge-transfer channel in the device with the aim of minimising the impact of traps during readout. Previous studies for the Euclid VIS instrument considered two devices, the e2v CCD204 and CCD273, the serial register of the former having a 50 μm channel and the latter having a 20 μm channel. The reduction in channel width was previously modelled to give an approximate 1.6× reduction in charge storage volume, verified experimentally to have a reduction in charge transfer inefficiency of 1.7×. The methods used to simulate the reduction approximated the charge cloud to a sharp-edged volume within which the probability of capture by traps was 100%. For high signals and slow readout speeds, this is a reasonable approximation. However, for low signals and higher readout speeds, the approximation falls short. Here we discuss a new method of simulating and calculating charge storage variations with device design changes, considering the absolute probability of capture across the pixel, bringing validity to all signal sizes and readout speeds. Using this method, we

Bifurcation of space-charge wave in a plasma waveguide including the wake potential effect

Energy Technology Data Exchange (ETDEWEB)

Lee, Myoung-Jae [Department of Physics and Research Institute for Natural Sciences, Hanyang University, Seoul 04763 (Korea, Republic of); Jung, Young-Dae, E-mail: ydjung@hanyang.ac.kr [Department of Applied Physics and Department of Bionanotechnology, Hanyang University, Ansan, Kyunggi-Do 15588, South Korea and Department of Physics, Applied Physics, and Astronomy, Rensselaer Polytechnic Institute, 110 8th Street, Troy, New York 12180-3590 (United States)

2016-09-15

The wake potential effects on the propagation of the space-charge dust ion-acoustic wave are investigated in a cylindrically bounded dusty plasma with the ion flow. The results show that the wake potential would generate the double frequency modes in a cylindrically bounded dusty plasma. It is found that the upper mode of the wave frequency with the root of higher-order is smaller than that with the root of lower-order in intermediate wave number domains. However, the lower mode of the scaled wave frequency with the root of higher-order is found to be greater than that with the root of lower-order. It is found that the influence in the order of the root of the Bessel function on the wave frequency of the space-charge dust-ion-acoustic wave in a cylindrically confined dusty plasma decreases with an increase in the propagation wave number. It is also found that the double frequency modes increase with increasing Mach number due to the ion flow in a cylindrical dusty plasma. In addition, it is found that the upper mode of the group velocity decreases with an increase in the scaled radius of the plasma cylinder. However, it is shown that the lower mode of the scaled group velocity of the space-charge dust ion acoustic wave increases with an increase in the radius of the plasma cylinder. The variation of the space-charge dust-ion-acoustic wave due to the wake potential and geometric effects is also discussed.

Consensus shaping and safe space public participation processes

Energy Technology Data Exchange (ETDEWEB)

Andersson, Kjell [Karita Research AB, Taeaby (Sweden)

2015-07-01

map public participation - consultation, consensus shaping processes and safe space. In contrast to consensus shaping processes, in the safe space approach there is no intention to develop solutions together between the implementer and other stakeholders. In comparison with the ladder, the basic approaches offer advantages for the mapping of public participation processes: If you strive for consensus or ''only'' clarity and awareness is a crucial question to be answered before a process is launched as it determines which stakeholders can join and which goals are feasible to reach. It is easier to use in assigning properties to a process, as it more straight-forward to understand if a process is consensus shaping or a safe space than where it is on the ladder. It clarifies better the links between the participation processes and the actual political and/or legal decision-making process. A consensus shaping process should produce real advice (or even decisions) but a safe space is limited to improving the decision making base with enhanced clarity.

Consensus shaping and safe space public participation processes

International Nuclear Information System (INIS)

Andersson, Kjell

2015-01-01

map public participation - consultation, consensus shaping processes and safe space. In contrast to consensus shaping processes, in the safe space approach there is no intention to develop solutions together between the implementer and other stakeholders. In comparison with the ladder, the basic approaches offer advantages for the mapping of public participation processes: If you strive for consensus or ''only'' clarity and awareness is a crucial question to be answered before a process is launched as it determines which stakeholders can join and which goals are feasible to reach. It is easier to use in assigning properties to a process, as it more straight-forward to understand if a process is consensus shaping or a safe space than where it is on the ladder. It clarifies better the links between the participation processes and the actual political and/or legal decision-making process. A consensus shaping process should produce real advice (or even decisions) but a safe space is limited to improving the decision making base with enhanced clarity.

Numerical simulation of amplification of space charge waves in n-InP films

International Nuclear Information System (INIS)

Garcia-Barrientos, Abel; Palankovski, Vassil

2011-01-01

The non-linear interaction of space charge waves including the amplification in microwave and millimeter wave range in n-InP films, possessing the negative differential conductance phenomenon, is investigated theoretically. Both the amplified signal and the generation of harmonics of the input signal are demonstrated, which are due to non-linear effect of the negative differential resistance. It is possible to observe an amplification of the space charge waves in n-InP films of submicron thicknesses at essentially higher frequencies f <70 GHz, when compared with n-GaAs films f < 44 GHz. The increment observed in the gain is due to the larger dynamic range in n-InP than in n-GaAs films.

Study by simulation the influence of temperature on the formation of space charge in the dielectric multilayer Under DC Electric stress

Directory of Open Access Journals (Sweden)

Y. A. Baadj

2017-06-01

Full Text Available Multidielectric polyethylene is a material that is generally employed as insulation for  the HVDC isolations. In this paper, the influence of temperature on space charge dynamics has been studied, low-density polyethylene (LDPE and Fluorinated Ethylene Propylene (FEP sandwiched between two electrodes were subjected to voltage application of 5kV (14.3 kV/mm for extended duration of time and the space charge measurements were taken using bipolar model is one-dimensional, taking into account trapping, detrapping and the rencommbinaison in order to determine the charge density and electric field of the sample depending on the thickness. The simulation was carried out at three different temperatures (20, 40,  and 60°C. The results of this model going to compare with experimental space charge measurements . Finally, simulation results demonstrated that the temperature has many effects on the dynamic space charge  and of influences the charge injection, charge mobility, electrical conduction, trapping and detrapping.

Influence of electric current intensity on the performance of electroformed copper liner for shaped charge application

Directory of Open Access Journals (Sweden)

Tamer Elshenawy

2017-12-01

Full Text Available Electrolytic Copper used in the shaped charge liner manufacturing can be produced from acid solution using electro-deposition technique. The intensity of the applied electric current controls the quality of the produced copper grade. The electric current intensity within the electrolytic acidic solution cell with the minimum oxygen and sulfur elements in the produced copper was optimized and found to be 30–40 A/Ft2. The elemental composition of the obtained electrolytic copper was determined using high-end stationary vacuum spectrometer, while the oxygen was determined precisely using ELTRA ONH-2000 apparatus. Besides, SEM was used to investigate the shape of the copper texture inside the deposited layers and to determine the average grain size. New relations have been obtained between the applied current intensity and both the oxygen and sulfur contents and the average grain size of the produced copper. Experimental result showed that when the applied current density increases to a certain limit, the oxygen and sulfur content in the electrolytic copper decreases. Performance of the produced copper liner was investigated by the static firing of a small caliber shaped charge containing an electro-formed copper liners, where the penetration depth of the optimized electrolytic liner was enhanced by 22.7% compared to that of baseline non-optimized liner.

Simulation of Cascaded Longitudinal-Space-Charge Amplifier at the Fermilab Accelerator Science & Technology (Fast) Facility

Energy Technology Data Exchange (ETDEWEB)

Halavanau, A. [Northern Illinois U.; Piot, P. [Northern Illinois U.

2015-12-01

Cascaded Longitudinal Space Charge Amplifiers (LSCA) have been proposed as a mechanism to generate density modulation over a board spectral range. The scheme has been recently demonstrated in the optical regime and has confirmed the production of broadband optical radiation. In this paper we investigate, via numerical simulations, the performance of a cascaded LSCA beamline at the Fermilab Accelerator Science & Technology (FAST) facility to produce broadband ultraviolet radiation. Our studies are carried out using elegant with included tree-based grid-less space charge algorithm.

Theory of space-charge polarization for determining ionic constants of electrolytic solutions

Science.gov (United States)

Sawada, Atsushi

2007-06-01

A theoretical expression of the complex dielectric constant attributed to space-charge polarization has been derived under an electric field calculated using Poisson's equation considering the effects of bound charges on ions. The frequency dependence of the complex dielectric constant of chlorobenzene solutions doped with tetrabutylammonium tetraphenylborate (TBATPB) has been analyzed using the theoretical expression, and the impact of the bound charges on the complex dielectric constant has been clarified quantitatively in comparison with a theory that does not consider the effect of the bound charges. The Stokes radius of TBA +(=TPB-) determined by the present theory shows a good agreement with that determined by conductometry in the past; hence, the present theory should be applicable to the direct determination of the mobility of ion species in an electrolytic solution without the need to measure ionic limiting equivalent conductance and transport number.

O({alpha}{sub s}) heavy flavor corrections to charged current deep-inelastic scattering in Mellin space

Energy Technology Data Exchange (ETDEWEB)

Bluemlein, J.; Hasselhuhn, A.; Kovacikova, P.; Moch, S.

2011-04-15

We provide a fast and precise Mellin-space implementation of the O({alpha}{sub s}) heavy flavor Wilson coefficients for charged current deep inelastic scattering processes. They are of importance for the extraction of the strange quark distribution in neutrino-nucleon scattering and the QCD analyses of the HERA charged current data. Errors in the literature are corrected. We also discuss a series of more general parton parameterizations in Mellin space. (orig.)

Investigations of space charge effects in the cryogenic gas filled stopping cell for the FRS ion catcher

Energy Technology Data Exchange (ETDEWEB)

Heisse, Fabian [IKTP, TU Dresden (Germany); GSI Helmholtzzentrum fuer Schwerionenforschung (Germany); Dickel, Timo; Plass, Wolfgang; Geissel, Hans; Scheidenberger, Christoph [II. Physikalisches Institut, JLU Giessen (Germany); GSI Helmholtzzentrum fuer Schwerionenforschung (Germany); Reiter, Moritz Pascal; Rink, Ann-Kathrin [II. Physikalisches Institut, JLU Giessen (Germany); Zuber, Kai [IKTP, TU Dresden (Germany); Collaboration: FRS Ion Catcher-Collaboration

2015-07-01

At the FRS Ion Catcher experiment precision mass measurements of short lived projectile and fission fragments are performed. Therefore highly charged ions with relativistic energies need to be thermalized to kinetic energies of several eV. This process takes place in the cryogenic gas filled stopping cell (CSC). All stopping cells suffer at large ion rates under space charge effects, which lead to decreasing efficiencies and can also influence the extraction time. Thus the understanding of space charge effects is of greatest importance to make full use of the higher yields at future rare ion beam facilities like FAIR. For this purpose simulation with the software SIMION {sup registered} concerning space charge effects were done. In this presentation the calculated transport efficiency of the CSC for different intensities, electric fields and spill structures are discussed and compared with measured results. Furthermore an outlook and first results of the simulation for the new CSC for the Low-Energy Branch at FAIR are given.

Efficiency of swimming of micro-organism and singularity in shape space

OpenAIRE

Kawamura, Masako

1996-01-01

Micro-organisms can be classified into three different types according to their size. We study the efficiency of the swimming of micro-organism in two dimensional fluid as a device for helping the explanation of this hierarchy in the size. We show that the efficiency of flagellate becomes unboundedly large, whereas that of ciliate has the upper bound. The unboundedness is related to the curious feature of the shape space, that is, a singularity at the basic shape of flagellate.

Modeling space charge in beams for heavy-ion fusion

International Nuclear Information System (INIS)

Sharp, W.M.

1995-01-01

A new analytic model is presented which accurately estimates the radially averaged axial component of the space-charge field of an axisymmetric heavy-ion beam in a cylindrical beam pipe. The model recovers details of the field near the beam ends that are overlooked by simpler models, and the results compare well to exact solutions of Poisson's equation. Field values are shown for several simple beam profiles and are compared with values obtained from simpler models

The Social Shaping of Technology: A New Space for Politics?

DEFF Research Database (Denmark)

Yoshinaka, Yutaka; Clausen, Christian; Hansen, Anne Grethe

2003-01-01

change. We identify a new perspective on political processes, with a broader focus on the political dimensions of technological decision-making, and a broader treatment of socio-technical space, maintaining a focus on inclusion and exclusion of actors, salient issues and how they are dealt...... effects, which are non-neutral and distributed, as the processes of shaping themselves have been. The chapter develops the notion of SST through socio-technical spaces. Here a heterogeneous set of elements, comprising of techniques, social actors, attribution of meanings, and problem definitions, etc...

A modified space charge routine for high intensity bunched beams

International Nuclear Information System (INIS)

Lapostolle, P.; Garnett, R.W.; Wangler, T.P.

1996-01-01

In 1991 a space charge calculation for bunched beam with a three-dimensional ellipsoid was proposed, replacing the usual SCHEFF routines. It removes the cylindrical symmetry required in SCHEFF and avoids the point to point interaction computation, whose number of simulation points is limited. This routine has now been improved with the introduction of two or three ellipsoids giving a good representation of the complex non-symmetrical form of the bunch (unlike the 3-d ellipsoidal assumption). The ellipsoidal density distributions are computed with a new method, avoiding the difficulty encountered near the centre (the axis in 2-d problems) by the previous method. It also provides a check of the ellipsoidal symmetry for each part of the distribution. Finally, the Fourier analysis reported in 1991 has been replaced by a very convenient Hermite expansion, which gives a simple but accurate representation of practical distributions. Comparisons with other space charge routines have been made, particularly with the ones applying other techniques such as SCHEFF. Introduced in the versatile beam dynamics code DYNAC, it should provide a good tool for the study of the various parameters responsible for the halo formation in high intensity linacs. (orig.)

Observation of Octupole Driven Resonance Phenomena with Space Charge at the CERN Proton Synchrotron

CERN Document Server

Métral, E; Martini, M; Steerenberg, R; Franchetti, Giuliano; Hofmann, I

2006-01-01

Several benchmarking space charge experiments have been performed during the last few years in the CERN Proton Synchrotron. These controlled experiments are of paramount importance to validate the present very powerful simulation codes. The observations of the combined effect of space charge and nonlinear resonance on beam loss and emittance, using a single controllable octupole during ~ 1 s at 1.4 GeV kinetic energy, are discussed in some detail in the present paper. By lowering the working point towards the octupolar resonance, a gradual transition from a regime of loss-free core emittance blow-up to a regime of continuous loss was found.

Space charge effects and coherent stability limits in barrier buckets

Directory of Open Access Journals (Sweden)

Oliver Boine-Frankenheim

2003-03-01

Full Text Available A large-scale Vlasov simulation study of the microwave instability below transition energy in a beam confined between two barrier pulses is performed. Starting from a matched distribution function for the confined ion beam including the space charge impedance the stability threshold in the longitudinal impedance plane is obtained. A simple stability criterium is found to be in good agreement with the simulation results.

Progress in 3D Space-charge Calculations in the GPT Code

NARCIS (Netherlands)

Pöplau, G.; Rienen, van U.; Loos, de M.J.; Geer, van der S.B.

2004-01-01

The mesh-based 3D space-charge routine in the GPT (General Particle Tracer, Pulsar Physics) code scales linearly with the number of particles in terms of CPU time and allows a million particles to be tracked on a normal PC. The crucial ingredient of the routine is a non-equidistant multi-grid

Shape, Transverse Size, and Charged Hadron Multiplicity of Jets in pp Collisions at 7 TeV

Energy Technology Data Exchange (ETDEWEB)

Chatrchyan, Serguei [Yerevan Physics Inst. (Armenia); et al.

2012-06-01

Measurements of jet characteristics from inclusive jet production in proton-proton collisions at a centre-of-mass energy of 7 TeV are presented. The data sample was collected with the CMS detector at the LHC during 2010 and corresponds to an integrated luminosity of 36 inverse picobarns. The mean charged hadron multiplicity, the differential and integral jet shape distributions, and two independent moments of the shape distributions are measured as functions of the jet transverse momentum for jets reconstructed with the anti-kT algorithm. The measured observables are corrected to the particle level and compared with predictions from various QCD Monte Carlo generators.

Semi-analytic variable charge solitary waves involving dust phase-space vortices (holes)

Energy Technology Data Exchange (ETDEWEB)

Tribeche, Mouloud; Younsi, Smain; Amour, Rabia; Aoutou, Kamel [Plasma Physics Group, Faculty of Sciences-Physics, Theoretical Physics Laboratory, University of Bab-Ezzouar, USTHB BP 32, El Alia, Algiers 16111 (Algeria)], E-mail: mtribeche@usthb.dz

2009-09-15

A semi-analytic model for highly nonlinear solitary waves involving dust phase-space vortices (holes) is outlined. The variable dust charge is expressed in terms of the Lambert function and we take advantage of this transcendental function to investigate the localized structures that may occur in a dusty plasma with variable charge trapped dust particles. Our results which complement the previously published work on this problem (Schamel et al 2001 Phys. Plasmas 8 671) should be of basic interest for experiments that involve the trapping of dust particles in ultra-low-frequency dust acoustic modes.

Semi-analytic variable charge solitary waves involving dust phase-space vortices (holes)

International Nuclear Information System (INIS)

Tribeche, Mouloud; Younsi, Smain; Amour, Rabia; Aoutou, Kamel

2009-01-01

A semi-analytic model for highly nonlinear solitary waves involving dust phase-space vortices (holes) is outlined. The variable dust charge is expressed in terms of the Lambert function and we take advantage of this transcendental function to investigate the localized structures that may occur in a dusty plasma with variable charge trapped dust particles. Our results which complement the previously published work on this problem (Schamel et al 2001 Phys. Plasmas 8 671) should be of basic interest for experiments that involve the trapping of dust particles in ultra-low-frequency dust acoustic modes.

Whimsicality of multi-mode Hasegawa space-charge waves in a complex plasma containing collision-dominated electrons and streaming ions

Science.gov (United States)

Lee, Myoung-Jae; Jung, Young-Dae

2017-09-01

The influence of collision-dominated electrons on multi-mode Hasegawa space-charge waves are investigated in a complex plasma containing streaming ions. The dispersion relation for the multi-mode Hasegawa space-charge wave propagating in a cylindrical waveguide filled with dusty plasma containing collision-dominated electrons and streaming ions is derived by using the fluid equations and Poisson’s equation which lead to a Bessel equation. By the boundary condition, the roots of the Bessel function would characterize the property of space-charge wave propagation. It is found that two solutions exist for wave frequency, which are affected by the radius of waveguide and the roots of the Bessel function. The damping and growing modes are found to be enhanced by an increase of the radius. However, an increase of electron collision frequency would suppress the damping and the growing modes of the propagating space-charge wave in a cylindrical waveguide plasma.

An Improved Treatment of AC Space Charge Fields in Large Signal Simulation Codes

National Research Council Canada - National Science Library

Dialetis, D; Chernin, D; Antonsen, Jr., T. M; Levush, B

2006-01-01

An accurate representation of the AC space charge electric field is required in order to be able to predict the performance of linear beam tubes, including TWT's and klystrons, using a steady state...

Nuclear Charge Radii in the Region of Shape Isomerism at Z $\\leq$ 80

CERN Multimedia

2002-01-01

The determination of isotope shifts in the isotopic chain of Hg has led to quite a number of unexpected observations as the transition from slightly oblate to strongly prolate deformation below A~=~186, the shape coexistence in |1|8|5Hg and a huge odd-even staggering of the charge radii in the region 181~@$<$~ Until now it is quite open if the observed instability of the nuclear shape is an isolated and unique feature of the light Hg isotopes and how it changes with Z and depends on the shell and pairing energies.\\\\ \\\\ Therefore we propose to carry out a study of the isotope shifts in the neighbouring isotopes of the elements Au and Pt which can be obtained at ISOLDE as daughters of a primary Hg beam. Resonance ionization spectroscopy will be applied as a novel technique at ISOLDE. The time of flight of the photo ionized Au (or Pt) isotope in a drift tube will be used to get rid of any background events.

Space charge and steady state current in LDPE samples containing a permittivity/conductivity gradient

DEFF Research Database (Denmark)

Holbøll, Joachim; Bambery, K. R.; Fleming, R. J.

2000-01-01

Electromagnetic theory predicts that a dielectric sample in which a steady DC current of density ε is flowing, and in which the ratio of permittivity ε to conductivity σ varies with position, will acquire a space charge density j·grad(ε/σ). A simple and convenient way to generate an ε/σ gradient...... in a homogeneous sample is to establish a temperature gradient across it. The resulting spatial variation in ε is usually small in polymeric insulators, but the variation in σ can be appreciable. Laser induced pressure pulse (LIPP) measurements were made on 1.5 mm thick plaques of ultra pure LDPE equipped...... with vacuum-evaporated aluminium electrodes. Temperature differences up to 27°C were maintained across the samples, which were subjected to DC fields up to 20 kV/mm. Current density was measured as a function of temperature and field. Negligible thermally generated space charge was observed. The charge...

Space charge emission in cylindrical diode

International Nuclear Information System (INIS)

Torres-Córdoba, Rafael; Martínez-García, Edgar

2014-01-01

In this paper, a mathematical model to describe cylindrical electron current emissions through a physics approximation method is presented. The proposed mathematical approximation consists of analyzing and solving the nonlinear Poisson's equation, with some determined mathematical restrictions. Our findings tackle the problem when charge-space creates potential barrier that disable the steady-state of the beam propagation. In this problem, the potential barrier effects of electron's speed with zero velocity emitted through the virtual cathode happens. The interaction between particles and the virtual cathode have been to find the inter-atomic potentials as boundary conditions from a quantum mechanics perspective. Furthermore, a non-stationary spatial solution of the electrical potential between anode and cathode is presented. The proposed solution is a 2D differential equation that was linearized from the generalized Poisson equation. A single condition was used solely, throughout the radial boundary conditions of the current density formation

A multislit transverse-emittance diagnostic for space-charge-dominated electron beams

International Nuclear Information System (INIS)

Piot, P.; Song, J.; Li, R.

1997-01-01

Jefferson Lab is developing a 10 MeV injector to provide an electron beam for a high-power free-electron laser (FEL). To characterize the transverse phase space of the space-charged-dominated beam produced by this injector, the authors designed an interceptive multislit emittance diagnostic. It incorporates an algorithm for phase-space reconstruction and subsequent calculation of the Twiss parameters and emittance for both transverse directions at an update rate exceeding 1 Hz, a speed that will facilitate the transverse-phase-space matching between the injector and the FEL's accelerator that is critical for proper operation. This paper describes issues pertaining to the diagnostic's design. It also discusses the acquisition system, as well as the software algorithm and its implementation in the FEL control system. First results obtained from testing this diagnostic in Jefferson Lab's Injector Test Stand are also included

KOBRA 3 - a code for the calculation of space-charge-influenced trajectories in 3-dimensions

International Nuclear Information System (INIS)

Spaedtke, P.; Wipf, S.

1989-06-01

KOBRA3 is a three-dimensional multi-purpose program, written in standard FORTRAN77. The main purpose of the program is to calculate the trajectories of charged particles through a static electro-magnetic field in three dimensions. If space charge is not negligible its influence is taken into account by an iterative process. The Laplace equation is solved for the scalar potential. During the ray tracing, in which the equations of motion for charged particles are solved, the space charge term in the Poisson equation is distributed onto the mesh. By repeating this procedure the steady-state Vlasov equation is solved: ∇ 2 φ+∫∫∫f p dxdydz = 0, where φ is the electro-static potential and f p (r vector, v vector) describes the distribution of the charged particles in space. KOBRA3 can handle finite plasma boundaries, which are found by the program automatically. Special features are included within the program to investigate the beam quality (emittance, transverse energy), and to display the geometry, the trajectories and the potential and magnetic fields graphically. The modular structure of the program enables the user to create his (her) own diagnostic programs or interfaces to the main program. This report is intended to facilitate the use of KOBRA3 by describing the theory, structure and numerical methods used. At GSI (Gesellschaft fuer Schwerionenforschung) the program runs on an IBM 3090-40E. The program has been installed on other machines e.g. CRAY XM-P, CRAY II, VAX 8600, IBM 3090-200, IBM 3033, ATARI ST, IBM-AT. (orig./HSI)

Analysis of the formation mechanism of the slug and jet center hole of axisymmetric shaped charges

Science.gov (United States)

Baoxiang, Ren; Gang, Tao; Peng, Wen; Changxing, Du; Chunqiao, Pang; Hongbo, Meng

2018-06-01

In the jet formation process of axisymmetric shaped charges, the slug is also formed. There is always a central hole in the symmetry axis of the jet and slug. The phenomenon was rarely mentioned and analyzed by the classical theory of shaped charges. For this problem, this paper attempts to explain the existence of the central hole in the jet and slug. Based on the analysis of recovery slug, we know that the jet and slug are in solid state in the process of formation. Through the analysis of X-flash radiographs of the stretching jet and particulation fracture, it is confirmed that the center holes in the jet are also present. Meanwhile, through the analysis of the microstructure of the recovered slug, it is found that there is a wave disturbance near the surface of the central hole. It can be speculated that the wave disturbance also exist in the jet. This effect may be one of the reasons for jet breakup. Due to the presence of the central hole in the jet, the density deficit of the jet obtained by other tests is very reasonable.

Cross-talk between Rho and Rac GTPases drives deterministic exploration of cellular shape space and morphological heterogeneity.

Science.gov (United States)

Sailem, Heba; Bousgouni, Vicky; Cooper, Sam; Bakal, Chris

2014-01-22

One goal of cell biology is to understand how cells adopt different shapes in response to varying environmental and cellular conditions. Achieving a comprehensive understanding of the relationship between cell shape and environment requires a systems-level understanding of the signalling networks that respond to external cues and regulate the cytoskeleton. Classical biochemical and genetic approaches have identified thousands of individual components that contribute to cell shape, but it remains difficult to predict how cell shape is generated by the activity of these components using bottom-up approaches because of the complex nature of their interactions in space and time. Here, we describe the regulation of cellular shape by signalling systems using a top-down approach. We first exploit the shape diversity generated by systematic RNAi screening and comprehensively define the shape space a migratory cell explores. We suggest a simple Boolean model involving the activation of Rac and Rho GTPases in two compartments to explain the basis for all cell shapes in the dataset. Critically, we also generate a probabilistic graphical model to show how cells explore this space in a deterministic, rather than a stochastic, fashion. We validate the predictions made by our model using live-cell imaging. Our work explains how cross-talk between Rho and Rac can generate different cell shapes, and thus morphological heterogeneity, in genetically identical populations.

Integration Assessment of Visiting Vehicle Induced Electrical Charging of the International Space Station Structure

Science.gov (United States)

Kramer, Leonard; Kerslake, Thomas W.; Galofaro, Joel T.

2010-01-01

The International Space Station (ISS) undergoes electrical charging in low Earth orbit (LEO) due to positively biased, exposed conductors on solar arrays that collect electrical charges from the space plasma. Exposed solar array conductors predominately collect negatively charged electrons and thus drive the metal ISS structure electrical ground to a negative floating potential (FP) relative to plasma. This FP is variable in location and time as a result of local ionospheric conditions. ISS motion through Earth s magnetic field creates an addition inductive voltage up to 20 positive and negative volts across ISS structure depending on its attitude and location in orbit. ISS Visiting Vehicles (VVs), such as the planned Orion crew exploration vehicle, contribute to the ISS plasma charging processes. Upon physical contact with ISS, the current collection properties of VVs combine with ISS. This is an ISS integration concern as FP must be controlled to minimize arcing of ISS surfaces and ensure proper management of extra vehicular activity crewman shock hazards. This report is an assessment of ISS induced charging from docked Orion vehicles employing negatively grounded, 130 volt class, UltraFlex (ATK Space Systems) solar arrays. To assess plasma electron current collection characteristics, Orion solar cell test coupons were constructed and subjected to plasma chamber current collection measurements. During these tests, coupon solar cells were biased between 0 and 120 V while immersed in a simulated LEO plasma. Tests were performed using several different simulated LEO plasma densities and temperatures. These data and associated theoretical scaling of plasma properties, were combined in a numerical model which was integrated into the Boeing Plasma Interaction Model. It was found that the solar array design for Orion will not affect the ISS FP by more than about 2 V during worst case charging conditions. This assessment also motivated a trade study to determine

Light-induced space-charge fields for the structuration of dielectric materials

International Nuclear Information System (INIS)

Eggert, H.A.

2006-11-01

Light-induced space-charge fields in lithium-niobate crystals are used for patterning of dielectric materials. This includes tailored ferroelectric domains in the bulk of the crystal, different sorts of micro and nanoparticles on a crystal surface, as well as poling of electrooptic chromophores. A stochastical model is introduced, which can describe the spatial inhomogeneous domain inversion. (orig.)

Assessment and Control of Spacecraft Charging Risks on the International Space Station

Science.gov (United States)

Koontz, Steve; Valentine, Mark; Keeping, Thomas; Edeen, Marybeth; Spetch, William; Dalton, Penni

2004-01-01

The International Space Station (ISS) operates in the F2 region of Earth's ionosphere, orbiting at altitudes ranging from 350 to 450 km at an inclination of 51.6 degrees. The relatively dense, cool F2 ionospheric plasma suppresses surface charging processes much of the time, and the flux of relativistic electrons is low enough to preclude deep dielectric charging processes. The most important spacecraft charging processes in the ISS orbital environment are: 1) ISS electrical power system interactions with the F2 plasma, 2) magnetic induction processes resulting from flight through the geomagnetic field and, 3) charging processes that result from interaction with auroral electrons at high latitude. Recently, the continuing review and evaluation of putative ISS charging hazards required by the ISS Program Office revealed that ISS charging could produce an electrical shock hazard to the ISS crew during extravehicular activity (EVA). ISS charging risks are being evaluated in an ongoing measurement and analysis campaign. The results of ISS charging measurements are combined with a recently developed model of ISS charging (the Plasma Interaction Model) and an exhaustive analysis of historical ionospheric variability data (ISS Ionospheric Specification) to evaluate ISS charging risks using Probabilistic Risk Assessment (PRA) methods. The PRA combines estimates of the frequency of occurrence and severity of the charging hazards with estimates of the reliability of various hazard controls systems, as required by NASA s safety and risk management programs, to enable design and selection of a hazard control approach that minimizes overall programmatic and personnel risk. The PRA provides a quantitative methodology for incorporating the results of the ISS charging measurement and analysis campaigns into the necessary hazard reports, EVA procedures, and ISS flight rules required for operating ISS in a safe and productive manner.

Non-linear shape functions over time in the space-time finite element method

Directory of Open Access Journals (Sweden)

Kacprzyk Zbigniew

2017-01-01

Full Text Available This work presents a generalisation of the space-time finite element method proposed by Kączkowski in his seminal of 1970’s and early 1980’s works. Kączkowski used linear shape functions in time. The recurrence formula obtained by Kączkowski was conditionally stable. In this paper, non-linear shape functions in time are proposed.

Investigation of space charge distribution of low-density polyethylene/GO-GNF (graphene oxide from graphite nanofiber) nanocomposite for HVDC application.

Science.gov (United States)

Kim, Yoon Jin; Ha, Son-Tung; Lee, Gun Joo; Nam, Jin Ho; Ryu, Ik Hyun; Nam, Su Hyun; Park, Cheol Min; In, Insik; Kim, Jiwan; Han, Chul Jong

2013-05-01

This paper reported a research on space charge distribution in low-density polyethylene (LDPE) nanocomposites with different types of graphene and graphene oxide (GO) at low filler content (0.05 wt%) under high DC electric field. Effect of addition of graphene oxide or graphene, its dispersion in LDPE polymer matrix on the ability to suppress space charge generation will be investigated and compared with MgO/LDPE nanocomposite at the same filler concentration. At an applied electric field of 80 kV/mm, a positive packet-like charge was observed in both neat LDPE, MgO/LDPE, and graphene/LDPE nanocomposites, whereas only little homogenous space charge was observed in GO/LDPE nanocomposites, especially with GO synthesized from graphite nano fiber (GNF) which is only -100 nm in diameter. Our research also suggests that dispersion of graphene oxide particles on the polymer matrix plays a significant role to the performance of nanocomposites on suppressing packet-like space charge. From these results, it is expected that nano-sized GO synthesized from GNF can be a promising filler material to LDPE composite for HVDC applications.

Observation and simulation of space-charge effects in a radio-frequency photoinjector using a transverse multibeamlet distribution

Directory of Open Access Journals (Sweden)

M. Rihaoui

2009-12-01

Full Text Available We report on an experimental study of space-charge effects in a radio-frequency (rf photoinjector. A 5 MeV electron bunch, consisting of a number of beamlets separated transversely, was generated in an rf photocathode gun and propagated in the succeeding drift space. The collective interaction of these beamlets was studied for different experimental conditions. The experiment allowed the exploration of space-charge effects and its comparison with 3D particle-in-cell simulations. Our observations also suggest the possible use of a multibeam configuration to tailor the transverse distribution of an electron beam.

Carbon Nanotube/Space Durable Polymer Nanocomposite Films for Electrostatic Charge Dissipation

Science.gov (United States)

Smith, J. G., Jr.; Watson, K. A.; Thompson, C. M.; Connell, J. W.

2002-01-01

Low solar absorptivity, space environmentally stable polymeric materials possessing sufficient electrical conductivity for electrostatic charge dissipation (ESD) are of interest for potential applications on spacecraft as thin film membranes on antennas, solar sails, large lightweight space optics, and second surface mirrors. One method of imparting electrical conductivity while maintaining low solar absorptivity is through the use of single wall carbon nanotubes (SWNTs). However, SWNTs are difficult to disperse. Several preparative methods were employed to disperse SWNTs into the polymer matrix. Several examples possessed electrical conductivity sufficient for ESD. The chemistry, physical, and mechanical properties of the nanocomposite films will be presented.

Chebyshev blossoming in Müntz spaces: Toward shaping with Young diagrams

KAUST Repository

Ait-Haddou, Rachid

2013-08-01

The notion of a blossom in extended Chebyshev spaces offers adequate generalizations and extra-utilities to the tools for free-form design schemes. Unfortunately, such advantages are often overshadowed by the complexity of the resulting algorithms. In this work, we show that for the case of Müntz spaces with integer exponents, the notion of a Chebyshev blossom leads to elegant algorithms whose complexities are embedded in the combinatorics of Schur functions. We express the blossom and the pseudo-affinity property in Müntz spaces in terms of Schur functions. We derive an explicit expression for the Chebyshev-Bernstein basis via an inductive argument on nested Müntz spaces. We also reveal a simple algorithm for dimension elevation. Free-form design schemes in Müntz spaces with Young diagrams as shape parameters are discussed. © 2013 Elsevier Ltd. All rights reserved.

Chebyshev blossoming in Müntz spaces: Toward shaping with Young diagrams

KAUST Repository

Ait-Haddou, Rachid; Sakane, Yusuke; Nomura, Taishin

2013-01-01

The notion of a blossom in extended Chebyshev spaces offers adequate generalizations and extra-utilities to the tools for free-form design schemes. Unfortunately, such advantages are often overshadowed by the complexity of the resulting algorithms. In this work, we show that for the case of Müntz spaces with integer exponents, the notion of a Chebyshev blossom leads to elegant algorithms whose complexities are embedded in the combinatorics of Schur functions. We express the blossom and the pseudo-affinity property in Müntz spaces in terms of Schur functions. We derive an explicit expression for the Chebyshev-Bernstein basis via an inductive argument on nested Müntz spaces. We also reveal a simple algorithm for dimension elevation. Free-form design schemes in Müntz spaces with Young diagrams as shape parameters are discussed. © 2013 Elsevier Ltd. All rights reserved.

A note on dust grain charging in space plasmas

Science.gov (United States)

Rosenberg, M.; Mendis, D. A.

1992-01-01

Central to the study of dust-plasma interactions in the solar system is the electrostatic charging of dust grains. While previous calculations have generally assumed that the distributions of electrons and ions in the plasma are Maxwellian, most space plasmas are observed to have non-Maxwellian tails and can often be fit by a generalized Lorentzian (kappa) distribution. Here we use such a distribution to reevaluate the grain potential, under the condition that the dominant currents to the grain are due to electron and ion collection, as is the case in certain regions of space. The magnitude of the grain potential is found to be larger than that in a Maxwellian plasma as long as the electrons are described by a kappa distribution: this enhancement increased with ion mass and decreasing electron kappa. The modification of the grain potential in generalized Lorentzian plasmas has implications for both the physics (e.g., grain growth and disruption) and the dynamics of dust in space plasmas. These are also briefly discussed.

Modeling space-charge-limited currents in organic semiconductors: Extracting trap density and mobility

KAUST Repository

Dacuñ a, Javier; Salleo, Alberto

2011-01-01

We have developed and have applied a mobility edge model that takes drift and diffusion currents to characterize the space-charge-limited current in organic semiconductors into account. The numerical solution of the drift-diffusion equation allows

Detecting space-time disease clusters with arbitrary shapes and sizes using a co-clustering approach

Directory of Open Access Journals (Sweden)

Sami Ullah

2017-11-01

Full Text Available Ability to detect potential space-time clusters in spatio-temporal data on disease occurrences is necessary for conducting surveillance and implementing disease prevention policies. Most existing techniques use geometrically shaped (circular, elliptical or square scanning windows to discover disease clusters. In certain situations, where the disease occurrences tend to cluster in very irregularly shaped areas, these algorithms are not feasible in practise for the detection of space-time clusters. To address this problem, a new algorithm is proposed, which uses a co-clustering strategy to detect prospective and retrospective space-time disease clusters with no restriction on shape and size. The proposed method detects space-time disease clusters by tracking the changes in space–time occurrence structure instead of an in-depth search over space. This method was utilised to detect potential clusters in the annual and monthly malaria data in Khyber Pakhtunkhwa Province, Pakistan from 2012 to 2016 visualising the results on a heat map. The results of the annual data analysis showed that the most likely hotspot emerged in three sub-regions in the years 2013-2014. The most likely hotspots in monthly data appeared in the month of July to October in each year and showed a strong periodic trend.

Emittance control of a beam by shaping the transverse charge distribution, using a tomography diagnostic

International Nuclear Information System (INIS)

Yakimenko, V.; Babzien, M.; Ben-Zvi, I.; Malone, R.; Wang, X.J.

1998-06-01

A high-brightness beam is very important for many applications. A diagnostic that measures the multi-dimensional phase-space density-distribution of the electron bunch is a must for obtaining such beams. Measurement of a slice emittance has been achieved. Tomographic reconstruction of phase space was suggested and implemented using a single quadrupole scan. In the present work the authors give special attention to the accuracy of the phase space reconstruction and present an analysis using a transport line with nine focusing magnets and techniques to control the optical functions and phases. This diagnostic, coupled with control of the radial charge distribution of presents an opportunity to improve the beam brightness. Combining the slice emittance and tomography diagnostics lead to an unprecedented visualization of phase space distributions in 5 dimensional phase-space and an opportunity to perform high-order emittance corrections

Influence of space charge during the injection in Saturne II

International Nuclear Information System (INIS)

Lemaire, J.L.

Calculations were made in which a fixed acceptance window, established since the beginning of the injection, was considered, and a filling pattern that was a linear function of time was supposed. Evidently, these conditions are no longer met if the space charge modifies the wave number of the beam and, consequently, the filling rate changes with time. The importance of these conditions upon injection for the theoretical operation point zone 3 is reported

Space charge distributions in glass fibre/epoxy resin composites under dc 10 kV mm-1 electric field

International Nuclear Information System (INIS)

Tanaka, Hidesato; Ohki, Yoshimichi; Fukunaga, Kaori; Maeno, Takashi; Okamoto, Kenji

2007-01-01

In this paper, the authors discuss one- and three-dimensional space charge distributions in glass fibre/epoxy resin composites. By the conventional pulsed electroacoustic (PEA) method, only a one-dimensional distribution of the average charge over a whole area parallel to the two electrodes can be observed. Therefore, the authors have developed a new PEA system capable of measuring a three-dimensional space charge distribution. Using this system, they measured the charge distribution in glass fibre/epoxy resin composites made of lattice-woven glass fibre and epoxy resin. It has become clear that spatial variation in signal intensity observed depends on the internal structure of the composite. There appear repetitious positions where a high charge density is observed on the same lateral cross section along the vertical direction in the composite. Such positions are consistent with the intersections of the glass fibres. Accumulation of mobile charge carriers or appearance of polarization charge due to mismatch of the ratio of the conductivity and permittivity between the glass fibre and the epoxy resin is thought to be responsible for the PEA signals

Investigations of the Dynamics of Space Charged Dominated Beams

International Nuclear Information System (INIS)

York, Richard C.

2002-01-01

We propose to perform investigations of the dynamics of space charge dominated beams. These investigations will support present activities such as the electron ring project at the University of Maryland as well as provide an improved basis for future accelerator designs. Computer simulations will provide the primary research element with improved code development being an integral part of the activities during the first period. We believe that one of the code development projects provides a unique strategy for the inclusion of longitudinal dynamics, and that this concept should provide a computationally rapid research tool

Investigations of the Dynamics of Space Charged Dominated Beams

Energy Technology Data Exchange (ETDEWEB)

York, Richard C.

2002-08-01

We propose to perform investigations of the dynamics of space charge dominated beams. These investigations will support present activities such as the electron ring project at the University of Maryland as well as provide an improved basis for future accelerator designs. Computer simulations will provide the primary research element with improved code development being an integral part of the activities during the first period. We believe that one of the code development projects provides a unique strategy for the inclusion of longitudinal dynamics, and that this concept should provide a computationally rapid research tool.

An integrodifferential Dirac equation with quantized charge in one space dimension

International Nuclear Information System (INIS)

Ranada, A.F.

1985-01-01

An integrodifferential Dirac equation in one space dimension is proposed, such that there is a close correspondence between its solutions and a subset of those of the sine-Gordon equation. It has solitonic solutions, quantized charge and positive definite energy density, so that it can be considered a spinorial version of sine-Gordon. Accordingly, it could be named the sine-Dirac equation. (orig.)

Modeling space-charge-limited currents in organic semiconductors: Extracting trap density and mobility

KAUST Repository

Dacuña, Javier

2011-11-28

We have developed and have applied a mobility edge model that takes drift and diffusion currents to characterize the space-charge-limited current in organic semiconductors into account. The numerical solution of the drift-diffusion equation allows the utilization of asymmetric contacts to describe the built-in potential within the device. The model has been applied to extract information of the distribution of traps from experimental current-voltage measurements of a rubrene single crystal from Krellner showing excellent agreement across several orders of magnitude in the current. Although the two contacts are made of the same metal, an energy offset of 580 meV between them, ascribed to differences in the deposition techniques (lamination vs evaporation) was essential to correctly interpret the shape of the current-voltage characteristics at low voltage. A band mobility of 0.13cm 2V-1s-1 for holes is estimated, which is consistent with transport along the long axis of the orthorhombic unit cell. The total density of traps deeper than 0.1 eV was 2.2×1016cm -3. The sensitivity analysis and error estimation in the obtained parameters show that it is not possible to accurately resolve the shape of the trap distribution for energies deeper than 0.3 eV or shallower than 0.1 eV above the valence-band edge. The total number of traps deeper than 0.3 eV, however, can be estimated. Contact asymmetry and the diffusion component of the current play an important role in the description of the device at low bias and are required to obtain reliable information about the distribution of deep traps. © 2011 American Physical Society.

A Continuum Mechanical Approach to Geodesics in Shape Space

Science.gov (United States)

2010-01-01

mean curvature flow equation. Calc. Var., 3:253–271, 1995. [30] Siddharth Manay, Daniel Cremers , Byung-Woo Hong, Anthony J. Yezzi, and Stefano Soatto...P. W. Michor and D. Mumford. Riemannian geometries on spaces of plane curves. J. Eur. Math. Soc., 8:1–48, 2006. 37 [33] Peter W. Michor, David ... Cremers . Shape matching by variational computation of geodesics on a manifold. In Pattern Recognition, LNCS 4174, pages 142–151, 2006. [38] P

EGUN, Charged Particle Trajectories in Electromagnetic Focusing System

International Nuclear Information System (INIS)

Herrmannsfeldt, W.B.

2002-01-01

1 - Description of problem or function: EGUN computes trajectories of charged particles in electrostatic and magnetostatic focusing systems including the effects of space charge and self-magnetic fields. Starting options include Child's Law conditions on cathodes of various shapes, user-specified conditions input for each ray, and a combination of Child's Law conditions and user specifications. Either rectangular or cylindrically symmetric geometry may be used. Magnetic fields may be specified using an arbitrary configuration of coils, or the output of a magnet program, such as Poisson, or by an externally calculated array of the axial fields. 2 - Method of solution: The program first solves Laplace's equation. Next, the first iteration of electron trajectories is started using one of the four starting options. On the first iteration cycle, space charge forces are calculated from the assumption of paraxial flow. As the rays are traced, space charge is computed and stored. After all the electron trajectories have been calculated, the program begins the second cycle by solving the Poisson equation with the space charge from the first iteration. Subsequent iteration cycles follow this pattern. The Poisson equation is solved by an alternate column relaxation technique known as the semi-iterative Chebyshev method. A fourth-order Runge-Kutta method is used to solve the relativistic differential equations of the trajectory calculations. 3 - Restrictions on the complexity of the problem - Maxima of: 9001 mesh points in a square mesh, 300 mesh points in the axial direction, 100 mesh points in the radial direction, 101 potentials, 51 rays. In the cylindrical coordinates, the magnetic fields are axially symmetric. In rectangular coordinates, the external field is assumed to be normal to the plane of the problem, which is assumed to be the median plane

Camera memory study for large space telescope. [charge coupled devices

Science.gov (United States)

Hoffman, C. P.; Brewer, J. E.; Brager, E. A.; Farnsworth, D. L.

1975-01-01

Specifications were developed for a memory system to be used as the storage media for camera detectors on the large space telescope (LST) satellite. Detectors with limited internal storage time such as intensities charge coupled devices and silicon intensified targets are implied. The general characteristics are reported of different approaches to the memory system with comparisons made within the guidelines set forth for the LST application. Priority ordering of comparisons is on the basis of cost, reliability, power, and physical characteristics. Specific rationales are provided for the rejection of unsuitable memory technologies. A recommended technology was selected and used to establish specifications for a breadboard memory. Procurement scheduling is provided for delivery of system breadboards in 1976, prototypes in 1978, and space qualified units in 1980.

Gain reduction due to space charge at high counting rates in multiwire proportional chambers

International Nuclear Information System (INIS)

Smith, G.C.; Mathieson, E.

1986-10-01

Measurements with a small MWPC of gas gain reduction, due to ion space charge at high counting rates, have been compared with theoretical predictions. The quantity ln(q/q 0 )/(q/q 0 ), where (q/q 0 ) is the relative reduced avalanche charge, has been found to be closely proportional to count rate, as predicted. The constant of proportionality is in good agreement with calculations made with a modified version of the original, simplified theory

Operating Deflection Shapes for the Space Shuttle Partial Stack Rollout

Science.gov (United States)

Buehrle, Ralph D.; Kappus, Kathy

2005-01-01

In November of 2003 a rollout test was performed to gain a better understanding of the dynamic environment for the Space Shuttle during transportation from the Vehicle Assembly Building to the launch pad. This was part of a study evaluating the methodology for including the rollout dynamic loads in the Space Shuttle fatigue life predictions. The rollout test was conducted with a partial stack consisting of the Crawler Transporter, Mobile Launch Platform, and the Solid Rocket Boosters with an interconnecting crossbeam. Instrumentation included over 100 accelerometers. Data was recorded for steady state speeds, start-ups and stops, and ambient wind excitations with the vehicle at idle. This paper will describe the operating deflection shape analysis performed using the measured acceleration response data. The response data for the steady state speed runs were dominated by harmonics of the forcing frequencies, which were proportional to the vehicle speed. Assuming a broadband excitation for the wind, analyses of the data sets with the vehicle at idle were used to estimate the natural frequencies and corresponding mode shapes. Comparisons of the measured modal properties with numerical predictions are presented.

Fabrication of Al2O3 Nano-Structure Functional Film on a Cellulose Insulation Polymer Surface and Its Space Charge Suppression Effect

Directory of Open Access Journals (Sweden)

Jian Hao

2017-10-01

Full Text Available Cellulose insulation polymer (paper/pressboard has been widely used in high voltage direct current (HVDC transformers. One of the most challenging issues in the insulation material used for HVDC equipment is the space charge accumulation. Effective ways to suppress the space charge injection/accumulation in insulation material is currently a popular research topic. In this study, an aluminium oxide functional film was deposited on a cellulose insulation pressboard surface using reactive radio frequency (RF magnetron sputtering. The sputtered thin film was characterized by the scanning electron microscopy/energy dispersive spectrometer (SEM/EDS, X-ray photoelectron spectroscopy (XPS, and X-ray diffraction (XRD. The influence of the deposited functional film on the dielectric properties and the space charge injection/accumulation behaviour was investigated. A preliminary exploration of the space charge suppression effect is discussed. SEM/EDS, XPS, and XRD results show that the nano-structured Al2O3 film with amorphous phase was successfully fabricated onto the fibre surface. The cellulose insulation pressboard surface sputtered by Al2O3 film has lower permittivity, conductivity, and dissipation factor values in the lower frequency (<103 Hz region. The oil-impregnated sputtered pressboard presents an apparent space-charge suppression effect. Compared with the pressboard sputtered with Al2O3 film for 90 min, the pressboard sputtered with Al2O3 film for 60 min had a better space charge suppression effect. Ultra-small Al2O3 particles (<10 nm grew on the surface of the larger nanoparticles. The nano-structured Al2O3 film sputtered on the fibre surface could act as a functional barrier layer for suppression of the charge injection and accumulation. This study offers a new perspective in favour of the application of insulation pressboard with a nano-structured function surface against space charge injection/accumulation in HVDC equipment.

Photosensitive space charge limited current in screen printed CdTe thin films

Science.gov (United States)

Vyas, C. U.; Pataniya, Pratik; Zankat, Chetan K.; Patel, Alkesh B.; Pathak, V. M.; Patel, K. D.; Solanki, G. K.

2018-05-01

Group II-VI Compounds have emerged out as most suitable in the class of photo sensitive material. They represent a strong position in terms of their applications in the field of detectors as well as photo voltaic devices. Cadmium telluride is the prime member of this Group, because of high acceptance of this material as active component in opto-electronic devices. In this paper we report preparation and characterization of CdTe thin films by using a most economical screen printing technique in association with sintering at 510°C temperature. Surface morphology and smoothness are prime parameters of any deposited to be used as an active region of devices. Thus, we studied of the screen printed thin film by means of atomic force microscopy (AFM) and scanning electron microscopy (SEM) for this purpose. However, growth processes induced intrinsic defects in fabricated films work as charge traps and affect the conduction process significantly. So the conduction mechanism of deposited CdTe thin film is studied under dark as well as illuminated conditions. It is found that the deposited films showed the space charge limited conduction (SCLC) mechanism and hence various parameters of space charge limited conduction (SCLC) of CdTe film were evaluated and discussed and the photo responsive resistance is also presented in this paper.

Rf and space-charge induced emittances in laser-driven rf guns

International Nuclear Information System (INIS)

Kim, Kwang-Je; Chen, Yu-Jiuan.

1988-10-01

Laser-driven rf electron guns are potential sources of high-current, low-emittance, short bunch-length electron beams, which are required for many advanced accelerator applications, such as free-electron lasers and injectors for high-energy machines. In such guns the design of which was pioneered at Los Alamos National Laboratory and which is currently being developed at several other laboratories, a high-power laser beam illuminates a photo-cathode surface placed on an end wall of an rf cavity. The main advantages of this type of gun are that the time structure of the electron beam is controlled by the laser, eliminating the need for bunchers, and that the electric field in rf cavities can be made very strong, so that the effects due to space-charge repulsion can be minimized. In this paper, we present an approximate but simple analysis for the transverse and longitudinal emittances in rf guns that takes into account both the time variation of the rf field and the space-charge effect. The results are compared and found to agree well with those from simulation. 7 refs., 6 figs

A parallel implementation of particle tracking with space charge effects on an INTEL iPSC/860

International Nuclear Information System (INIS)

Chang, L.; Bourianoff, G.; Cole, B.; Machida, S.

1993-05-01

Particle-tracking simulation is one of the scientific applications that is well-suited to parallel computations. At the Superconducting Super Collider, it has been theoretically and empirically demonstrated that particle tracking on a designed lattice can achieve very high parallel efficiency on a MIMD Intel iPSC/860 machine. The key to such success is the realization that the particles can be tracked independently without considering their interaction. The perfectly parallel nature of particle tracking is broken if the interaction effects between particles are included. The space charge introduces an electromagnetic force that will affect the motion of tracked particles in 3-D space. For accurate modeling of the beam dynamics with space charge effects, one needs to solve three-dimensional Maxwell field equations, usually by a particle-in-cell (PIC) algorithm. This will require each particle to communicate with its neighbor grids to compute the momentum changes at each time step. It is expected that the 3-D PIC method will degrade parallel efficiency of particle-tracking implementation on any parallel computer. In this paper, we describe an efficient scheme for implementing particle tracking with space charge effects on an INTEL iPSC/860 machine. Experimental results show that a parallel efficiency of 75% can be obtained

Radial space-charge-limited electron flow in semi-insulating GaN:Fe

Czech Academy of Sciences Publication Activity Database

Mareš, Jiří J.; Hubík, Pavel; Krištofik, Jozef; Prušáková, Lucie; Uxa, Štěpán; Paskova, T.; Evans, K.

2011-01-01

Roč. 110, č. 1 (2011), 013723/1-013723/6 ISSN 0021-8979 R&D Projects: GA ČR GAP204/10/0212 Institutional research plan: CEZ:AV0Z10100521 Keywords : gallium nitride * semi-insulator * space-charge-limited current Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.168, year: 2011

Estimation of the diameter-charge distribution in polydisperse electrically charged sprays of electrically insulating liquids

Energy Technology Data Exchange (ETDEWEB)

Rigit, A.R.H. [University of Sarawak, Faculty of Engineering, Kota Samarahan, Sarawak (Malaysia); Shrimpton, John S. [University of Southampton, Energy Technology Research Group, School of Engineering Sciences, Southampton (United Kingdom)

2009-06-15

The majority of scientific and industrial electrical spray applications make use of sprays that contain a range of drop diameters. Indirect evidence suggests the mean drop diameter and the mean drop charge level are usually correlated. In addition, within each drop diameter class there is every reason to suspect a distribution of charge levels exist for a particular drop diameter class. This paper presents an experimental method that uses the joint PDF of drop velocity and diameter, obtained from phase Doppler anemometry measurements, and directly obtained spatially resolved distributions of the mass and charge flux to obtain a drop diameter and charge frequency distribution. The method is demonstrated using several data-sets obtained from experimental measurements of steady poly-disperse sprays of an electrically insulating liquid produced with the charge injection technique. The space charge repulsion in the spray plume produces a hollow cone spray structure. In addition an approximate self-similarity is observed, with the maximum radial mass and charge flow occurring at r/d{proportional_to}200. The charge flux profile is slightly offset from the mass flux profile, and this gives direct evidence that the spray specific charge increases from approximately 20% of the bulk mean spray specific charge on the spray axis to approximately 200% of the bulk mean specific charge in the periphery of the spray. The results from the drop charge estimation model suggest a complex picture of the correlation between drop charge and drop diameter, with spray specific charge, injection velocity and orifice diameter all contributing to the shape of the drop diameter-charge distribution. Mean drop charge as a function of the Rayleigh limit is approximately 0.2, and is invariant with drop diameter and also across the spray cases tested. (orig.)

Estimation of the diameter-charge distribution in polydisperse electrically charged sprays of electrically insulating liquids

Science.gov (United States)

Rigit, A. R. H.; Shrimpton, John S.

2009-06-01

The majority of scientific and industrial electrical spray applications make use of sprays that contain a range of drop diameters. Indirect evidence suggests the mean drop diameter and the mean drop charge level are usually correlated. In addition, within each drop diameter class there is every reason to suspect a distribution of charge levels exist for a particular drop diameter class. This paper presents an experimental method that uses the joint PDF of drop velocity and diameter, obtained from phase Doppler anemometry measurements, and directly obtained spatially resolved distributions of the mass and charge flux to obtain a drop diameter and charge frequency distribution. The method is demonstrated using several data-sets obtained from experimental measurements of steady poly-disperse sprays of an electrically insulating liquid produced with the charge injection technique. The space charge repulsion in the spray plume produces a hollow cone spray structure. In addition an approximate self-similarity is observed, with the maximum radial mass and charge flow occurring at r/ d ~ 200. The charge flux profile is slightly offset from the mass flux profile, and this gives direct evidence that the spray specific charge increases from approximately 20% of the bulk mean spray specific charge on the spray axis to approximately 200% of the bulk mean specific charge in the periphery of the spray. The results from the drop charge estimation model suggest a complex picture of the correlation between drop charge and drop diameter, with spray specific charge, injection velocity and orifice diameter all contributing to the shape of the drop diameter-charge distribution. Mean drop charge as a function of the Rayleigh limit is approximately 0.2, and is invariant with drop diameter and also across the spray cases tested.

Study on discrete space charge effects in electron beams and guns

International Nuclear Information System (INIS)

Tang Tiantong

1990-01-01

The discrete space charge effects in electron beams are studied and a statistical dynamics equation of the ensemble of beam electrons is derived. An approximated analytical solution of this equation is given. This equation has been applied to beam crossover and field-emission and thermal-emission gun problems. The computer calculation results agree on the whole with those of Monte Carlo simulation and experimental data. (orig.)

The Effects of Space-Charge on the Dynamics of the Ion Booster in the Jefferson Lab EIC (JLEIC)

Energy Technology Data Exchange (ETDEWEB)

Bogacz, Alex [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Nissen, Edward [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)

2017-05-01

Optimization of the booster synchrotron design to operate in the extreme space-charge dominated regime is proposed. This study is motivated by the ultra-high luminosity promised by the JLEIC accelerator complex, which poses several beam dynamics and lattice design challenges for its individual components. We examine the effects of space charge on the dynamics of the booster synchrotron for the proposed JLEIC electron ion collider. This booster will inject and accumulate protons and heavy ions at an energy of 280 MeV and then engage in a process of acceleration and electron cooling to bring it to its extraction energy of 8 GeV. This would then be sent into the ion collider ring part of JLEIC. In order to examine the effects of space charge on the dynamics of this process we use the software SYNERGIA.

Particle trapping by nonlinear resonances and space charge

International Nuclear Information System (INIS)

Franchetti, G.; Hofmann, I.

2006-01-01

In the FAIR [C.D.R. http://www.gsi.de/GSI Future/cdr/] facility planned at GSI high space charge effects and nonlinear dynamics may play an important role for limiting nominal machine performance. The most relevant interplay of these two effects on the single particle dynamics has been proposed in terms of trapping of particles into stable islands [G. Franchetti, I. Hofmann, AIP Conf. Proc. 642 (2002) 260]. Subsequent numerical studies and dedicated experiments have followed [G. Franchetti et al., Phys. Rev. ST Accel. Beams 6 (2003) 124201; G. Franchetti et al., AIP Conf. Proc. 773 (2005) 137]. We present here the effect of the chromaticity on the mechanisms of halo formation induced by particle trapping into resonances

Radiation and Internal Charging Environments for Thin Dielectrics in Interplanetary Space

Science.gov (United States)

Minow, Joseph I.; Parker, Linda Neergaard; Altstatt, Richard L.

2004-01-01

Spacecraft designs using solar sails for propulsion or thin membranes to shade instruments from the sun to achieve cryogenic operating temperatures are being considered for a number of missions in the next decades. A common feature of these designs are thin dielectric materials that will be exposed to the solar wind, solar energetic particle events, and the distant magnetotail plasma environments encountered by spacecraft in orbit about the Earth-Sun L2 point. This paper will discuss the relevant radiation and internal charging environments developed to support spacecraft design for both total dose radiation effects as well as dose rate dependent phenomenon, such as internal charging in the solar wind and distant magnetotail environments. We will describe the development of radiation and internal charging environment models based on nearly a complete solar cycle of Ulysses solar wind plasma measurements over a complete range of heliocentric latitudes and the early years of the Geotail mission where distant magnetotail plasma environments were sampled beyond X(sub GSE) = -100 Re to nearly L2 (X(sub GSE) -236 Re). Example applications of the environment models are shown to demonstrate the radiation and internal charging environments of thin materials exposed to the interplanetary space plasma environments.

3D Simulations of Space Charge Effects in Particle Beams

Energy Technology Data Exchange (ETDEWEB)

Adelmann, A

2002-10-01

For the first time, it is possible to calculate the complicated three-dimensional proton accelerator structures at the Paul Scherrer Institut (PSI). Under consideration are external and self effects, arising from guiding and space-charge forces. This thesis has as its theme the design, implementation and validation of a tracking program for charged particles in accelerator structures. This work form part of the discipline of Computational Science and Engineering (CSE), more specifically in computational accelerator modelling. The physical model is based on the collisionless Vlasov-Maxwell theory, justified by the low density ({approx} 10{sup 9} protons/cm{sup 3}) of the beam and of the residual gas. The probability of large angle scattering between the protons and the residual gas is then sufficiently low, as can be estimated by considering the mean free path and the total distance a particle travels in the accelerator structure. (author)

3D Simulations of Space Charge Effects in Particle Beams

International Nuclear Information System (INIS)

Adelmann, A.

2002-10-01

For the first time, it is possible to calculate the complicated three-dimensional proton accelerator structures at the Paul Scherrer Institut (PSI). Under consideration are external and self effects, arising from guiding and space-charge forces. This thesis has as its theme the design, implementation and validation of a tracking program for charged particles in accelerator structures. This work form part of the discipline of Computational Science and Engineering (CSE), more specifically in computational accelerator modelling. The physical model is based on the collisionless Vlasov-Maxwell theory, justified by the low density (∼ 10 9 protons/cm 3 ) of the beam and of the residual gas. The probability of large angle scattering between the protons and the residual gas is then sufficiently low, as can be estimated by considering the mean free path and the total distance a particle travels in the accelerator structure. (author)

Pump laser-induced space-charge effects in HHG-driven time- and angle-resolved photoelectron spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Oloff, L.-P., E-mail: oloff@physik.uni-kiel.de; Hanff, K.; Stange, A.; Rohde, G.; Diekmann, F.; Bauer, M.; Rossnagel, K., E-mail: rossnagel@physik.uni-kiel.de [Institut für Experimentelle und Angewandte Physik, Christian-Albrechts-Universität zu Kiel, D-24098 Kiel (Germany)

2016-06-14

With the advent of ultrashort-pulsed extreme ultraviolet sources, such as free-electron lasers or high-harmonic-generation (HHG) sources, a new research field for photoelectron spectroscopy has opened up in terms of femtosecond time-resolved pump-probe experiments. The impact of the high peak brilliance of these novel sources on photoemission spectra, so-called vacuum space-charge effects caused by the Coulomb interaction among the photoemitted probe electrons, has been studied extensively. However, possible distortions of the energy and momentum distributions of the probe photoelectrons caused by the low photon energy pump pulse due to the nonlinear emission of electrons have not been studied in detail yet. Here, we systematically investigate these pump laser-induced space-charge effects in a HHG-based experiment for the test case of highly oriented pyrolytic graphite. Specifically, we determine how the key parameters of the pump pulse—the excitation density, wavelength, spot size, and emitted electron energy distribution—affect the measured time-dependent energy and momentum distributions of the probe photoelectrons. The results are well reproduced by a simple mean-field model, which could open a path for the correction of pump laser-induced space-charge effects and thus toward probing ultrafast electron dynamics in strongly excited materials.

Quantum computing based on space states without charge transfer

International Nuclear Information System (INIS)

Vyurkov, V.; Filippov, S.; Gorelik, L.

2010-01-01

An implementation of a quantum computer based on space states in double quantum dots is discussed. There is no charge transfer in qubits during a calculation, therefore, uncontrolled entanglement between qubits due to long-range Coulomb interaction is suppressed. Encoding and processing of quantum information is merely performed on symmetric and antisymmetric states of the electron in double quantum dots. Other plausible sources of decoherence caused by interaction with phonons and gates could be substantially suppressed in the structure as well. We also demonstrate how all necessary quantum logic operations, initialization, writing, and read-out could be carried out in the computer.

Shape space figure-8 solution of three body problem with two equal masses

Science.gov (United States)

Yu, Guowei

2017-06-01

In a preprint by Montgomery (https://people.ucsc.edu/~rmont/Nbdy.html), the author attempted to prove the existence of a shape space figure-8 solution of the Newtonian three body problem with two equal masses (it looks like a figure 8 in the shape space, which is different from the famous figure-8 solution with three equal masses (Chenciner and Montgomery 2000 Ann. Math. 152 881-901)). Unfortunately there is an error in the proof and the problem is still open. Consider the α-homogeneous Newton-type potential, 1/rα, using action minimization method, we prove the existence of this solution, for α \\in (1, 2) ; for α=1 (the Newtonian potential), an extra condition is required, which unfortunately seems hard to verify at this moment.

Space distribution and energy straggling of charged particles via Fokker-Planck equation

International Nuclear Information System (INIS)

Manservisi, S.; Molinari, V.; Nespoli, A.

1996-01-01

The Fokker-Planck equation describing a beam of charged particles entering a homogeneous medium is solved here for a stationary case. Interactions are taken into account through Coulomb cross-section. Starting from the charged-particle distribution as a function of velocity and penetration depth, some important kinetic quantities are calculated, like mean velocity, range and the loss of energy per unit space. In such quantities the energy straggling is taken into account. This phenomenon is not considered in the continuous slowing-down approximation that is commonly used to obtain the range and the stopping power. Finally the well-know Bohr of Bethe formula is found as a first-order approximation of the Fokker-Planck equation

Beam-envelope calculations of space-charge loaded beams in MeV dc ion-implantation facilities

International Nuclear Information System (INIS)

Urbanus, W.H.; Bannenberg, J.G.; Doorn, S.; Saris, F.W.; Koudijs, R.; Dubbelman, P.; Koelewijn, W.

1989-01-01

MeV dc ion accelerators are being developed that can deliver a beam current up to several hundred micro-amperes. At the low-energy part of the accelerator, the beam transport is space-charge dominated rather than emittance dominated. A system of differential equations has been derived, based on the Kapchinski-Vladimirski equations, which describe the envelope of a space-charge loaded ion beam, taking a longitudinal electrical field in an accelerating tube into account. The equations have been used to design the accelerator of a high-current 1 MV heavy-ion implantation facility. Furthermore, the design of a 2 MV accelerator is presented, which is used for analyzing techniques such as RBS and PIXE. Both facilities are based on single-ended Van de Graaff accelerators. (orig.)

Space-Charge Simulation of Integrable Rapid Cycling Synchrotron

Energy Technology Data Exchange (ETDEWEB)

Eldred, Jeffery [Fermilab; Valishev, Alexander [Fermilab

2017-05-01

Integrable optics is an innovation in particle accelerator design that enables strong nonlinear focusing without generating parametric resonances. We use a Synergia space-charge simulation to investigate the application of integrable optics to a high-intensity hadron ring that could replace the Fermilab Booster. We find that incorporating integrability into the design suppresses the beam halo generated by a mismatched KV beam. Our integrable rapid cycling synchrotron (iRCS) design includes other features of modern ring design such as low momentum compaction factor and harmonically canceling sextupoles. Experimental tests of high-intensity beams in integrable lattices will take place over the next several years at the Fermilab Integrable Optics Test Accelerator (IOTA) and the University of Maryland Electron Ring (UMER).

Shape, transverse size, and charged hadron multiplicity of jets in pp collisions at $\\sqrt{s}$ = 7 TeV

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Chatrchyan, Serguei; Sirunyan, Albert M; Tumasyan, Armen; Adam, Wolfgang; Bergauer, Thomas; Dragicevic, Marko; Erö, Janos; Fabjan, Christian; Friedl, Markus; Fruehwirth, Rudolf; Ghete, Vasile Mihai; Hammer, Josef; Hoch, Michael; Hörmann, Natascha; Hrubec, Josef; Jeitler, Manfred; Kiesenhofer, Wolfgang; Krammer, Manfred; Liko, Dietrich; Mikulec, Ivan; Pernicka, Manfred; Rahbaran, Babak; Rohringer, Christine; Rohringer, Herbert; Schöfbeck, Robert; Strauss, Josef; Taurok, Anton; Teischinger, Florian; Wagner, Philipp; Waltenberger, Wolfgang; Walzel, Gerhard; Widl, Edmund; Wulz, Claudia-Elisabeth; Mossolov, Vladimir; Shumeiko, Nikolai; Suarez Gonzalez, Juan; Bansal, Sunil; Benucci, Leonardo; De Wolf, Eddi A; Janssen, Xavier; Luyckx, Sten; Maes, Thomas; Mucibello, Luca; Ochesanu, Silvia; Roland, Benoit; Rougny, Romain; Selvaggi, Michele; Van Haevermaet, Hans; Van Mechelen, Pierre; Van Remortel, Nick; Van Spilbeeck, Alex; Blekman, Freya; Blyweert, Stijn; D'Hondt, Jorgen; Gonzalez Suarez, Rebeca; Kalogeropoulos, Alexis; Maes, Michael; Olbrechts, Annik; Van Doninck, Walter; Van Mulders, Petra; Van Onsem, Gerrit Patrick; Villella, Ilaria; Charaf, Otman; Clerbaux, Barbara; De Lentdecker, Gilles; Dero, Vincent; Gay, Arnaud; Hammad, Gregory Habib; Hreus, Tomas; Léonard, Alexandre; Marage, Pierre Edouard; Thomas, Laurent; Vander Velde, Catherine; Vanlaer, Pascal; Wickens, John; Adler, Volker; Beernaert, Kelly; Cimmino, Anna; Costantini, Silvia; Grunewald, Martin; Klein, Benjamin; Lellouch, Jérémie; Marinov, Andrey; Mccartin, Joseph; Ryckbosch, Dirk; Strobbe, Nadja; Thyssen, Filip; Tytgat, Michael; Vanelderen, Lukas; Verwilligen, Piet; Walsh, Sinead; Zaganidis, Nicolas; Basegmez, Suzan; Bruno, Giacomo; Caudron, Julien; Ceard, Ludivine; De Favereau De Jeneret, Jerome; Delaere, Christophe; Favart, Denis; Forthomme, Laurent; Giammanco, Andrea; Grégoire, Ghislain; Hollar, Jonathan; Lemaitre, Vincent; Liao, Junhui; Militaru, Otilia; Nuttens, Claude; Pagano, Davide; Pin, Arnaud; Piotrzkowski, Krzysztof; 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Nawrocki, Krzysztof; Romanowska-Rybinska, Katarzyna; Szleper, Michal; Wrochna, Grzegorz; Zalewski, Piotr; Almeida, Nuno; Bargassa, Pedrame; David Tinoco Mendes, Andre; Faccioli, Pietro; Ferreira Parracho, Pedro Guilherme; Gallinaro, Michele; Musella, Pasquale; Nayak, Aruna; Pela, Joao; Ribeiro, Pedro Quinaz; Seixas, Joao; Varela, Joao; Afanasiev, Serguei; Belotelov, Ivan; Bunin, Pavel; Gavrilenko, Mikhail; Golutvin, Igor; Gorbunov, Ilya; Karjavin, Vladimir; Konoplyanikov, Viktor; Kozlov, Guennady; Lanev, Alexander; Moisenz, Petr; Palichik, Vladimir; Perelygin, Victor; Shmatov, Sergey; Smirnov, Vitaly; Volodko, Anton; Zarubin, Anatoli; Evstyukhin, Sergey; Golovtsov, Victor; Ivanov, Yury; Kim, Victor; Levchenko, Petr; Murzin, Victor; Oreshkin, Vadim; Smirnov, Igor; Sulimov, Valentin; Uvarov, Lev; Vavilov, Sergey; Vorobyev, Alexey; Vorobyev, Andrey; Andreev, Yuri; Dermenev, Alexander; Gninenko, Sergei; Golubev, Nikolai; Kirsanov, Mikhail; Krasnikov, Nikolai; Matveev, Viktor; Pashenkov, Anatoli; Toropin, Alexander; Troitsky, Sergey; Epshteyn, Vladimir; Erofeeva, Maria; Gavrilov, Vladimir; Kossov, Mikhail; Krokhotin, Andrey; Lychkovskaya, Natalia; Popov, Vladimir; Safronov, Grigory; Semenov, Sergey; Stolin, Viatcheslav; Vlasov, Evgueni; Zhokin, Alexander; Belyaev, Andrey; Boos, Edouard; Dubinin, Mikhail; Dudko, Lev; Ershov, Alexander; Gribushin, Andrey; Kodolova, Olga; Lokhtin, Igor; Markina, Anastasia; Obraztsov, Stepan; Perfilov, Maxim; Petrushanko, Sergey; Sarycheva, Ludmila; Savrin, Viktor; Snigirev, Alexander; Andreev, Vladimir; Azarkin, Maksim; Dremin, Igor; Kirakosyan, Martin; Leonidov, Andrey; Mesyats, Gennady; Rusakov, Sergey V; Vinogradov, Alexey; Azhgirey, Igor; Bayshev, Igor; Bitioukov, Sergei; Grishin, Viatcheslav; Kachanov, Vassili; Konstantinov, Dmitri; Korablev, Andrey; Krychkine, Victor; Petrov, Vladimir; Ryutin, Roman; Sobol, Andrei; Tourtchanovitch, Leonid; Troshin, Sergey; Tyurin, Nikolay; Uzunian, Andrey; Volkov, Alexey; Adzic, Petar; Djordjevic, Milos; Ekmedzic, Marko; Krpic, Dragomir; Milosevic, Jovan; Aguilar-Benitez, Manuel; Alcaraz Maestre, Juan; Arce, Pedro; Battilana, Carlo; Calvo, Enrique; Cerrada, Marcos; Chamizo Llatas, Maria; Colino, Nicanor; De La Cruz, Begona; Delgado Peris, Antonio; Diez Pardos, Carmen; Domínguez Vázquez, Daniel; Fernandez Bedoya, Cristina; Fernández Ramos, Juan Pablo; Ferrando, Antonio; Flix, Jose; Fouz, Maria Cruz; Garcia-Abia, Pablo; Gonzalez Lopez, Oscar; Goy Lopez, Silvia; Hernandez, Jose M; Josa, Maria Isabel; Merino, Gonzalo; Puerta Pelayo, Jesus; Redondo, Ignacio; Romero, Luciano; Santaolalla, Javier; Senghi Soares, Mara; Willmott, Carlos; Albajar, Carmen; Codispoti, Giuseppe; de Trocóniz, Jorge F; Cuevas, Javier; Fernandez Menendez, Javier; Folgueras, Santiago; Gonzalez Caballero, Isidro; Lloret Iglesias, Lara; Vizan Garcia, Jesus Manuel; Brochero Cifuentes, Javier Andres; Cabrillo, Iban Jose; Calderon, Alicia; Chuang, Shan-Huei; Duarte Campderros, Jordi; Felcini, Marta; Fernandez, Marcos; Gomez, Gervasio; Gonzalez Sanchez, Javier; Jorda, Clara; Lobelle Pardo, Patricia; Lopez Virto, Amparo; Marco, Jesus; Marco, Rafael; Martinez Rivero, Celso; Matorras, Francisco; Munoz Sanchez, Francisca Javiela; Piedra Gomez, Jonatan; Rodrigo, Teresa; Rodríguez-Marrero, Ana Yaiza; Ruiz-Jimeno, Alberto; Scodellaro, Luca; Sobron Sanudo, Mar; Vila, Ivan; Vilar Cortabitarte, Rocio; Abbaneo, Duccio; Auffray, Etiennette; Auzinger, Georg; Baillon, Paul; Ball, Austin; Barney, David; Bernet, Colin; Bialas, Wojciech; Bloch, Philippe; Bocci, Andrea; Breuker, Horst; Bunkowski, Karol; Camporesi, Tiziano; Cerminara, Gianluca; Christiansen, Tim; Coarasa Perez, Jose Antonio; Curé, Benoît; D'Enterria, David; De Roeck, Albert; Di Guida, Salvatore; Dobson, Marc; Dupont-Sagorin, Niels; Elliott-Peisert, Anna; Frisch, Benjamin; Funk, Wolfgang; Gaddi, Andrea; Georgiou, Georgios; Gerwig, Hubert; Giffels, Manuel; Gigi, Dominique; Gill, Karl; Giordano, Domenico; Giunta, Marina; Glege, Frank; Gomez-Reino Garrido, Robert; Gouzevitch, Maxime; Govoni, Pietro; Gowdy, Stephen; Guida, Roberto; Guiducci, Luigi; Gundacker, Stefan; Hansen, Magnus; Hartl, Christian; Harvey, John; Hegeman, Jeroen; Hegner, Benedikt; Hoffmann, Hans Falk; Innocente, Vincenzo; Janot, Patrick; Kaadze, Ketino; Karavakis, Edward; Lecoq, Paul; Lenzi, Piergiulio; Lourenco, Carlos; Maki, Tuula; Malberti, Martina; Malgeri, Luca; Mannelli, Marcello; Masetti, Lorenzo; Mavromanolakis, Georgios; Meijers, Frans; Mersi, Stefano; Meschi, Emilio; Moser, Roland; Mozer, Matthias Ulrich; Mulders, Martijn; Nesvold, Erik; Nguyen, Matthew; Orimoto, Toyoko; Orsini, Luciano; Palencia Cortezon, Enrique; Perez, Emmanuelle; Petrilli, Achille; Pfeiffer, Andreas; Pierini, Maurizio; Pimiä, Martti; Piparo, Danilo; Polese, Giovanni; Quertenmont, Loic; Racz, Attila; Reece, William; Rodrigues Antunes, Joao; Rolandi, Gigi; Rommerskirchen, Tanja; Rovelli, Chiara; Rovere, Marco; Sakulin, Hannes; Santanastasio, Francesco; Schäfer, Christoph; Schwick, Christoph; Segoni, Ilaria; Sharma, Archana; Siegrist, Patrice; Silva, Pedro; Simon, Michal; Sphicas, Paraskevas; Spiga, Daniele; Spiropulu, Maria; Stoye, Markus; Tsirou, Andromachi; Vichoudis, Paschalis; Wöhri, Hermine Katharina; Worm, Steven; Zeuner, Wolfram Dietrich; Bertl, Willi; Deiters, Konrad; Erdmann, Wolfram; Gabathuler, Kurt; Horisberger, Roland; Ingram, Quentin; Kaestli, Hans-Christian; König, Stefan; Kotlinski, Danek; Langenegger, Urs; Meier, Frank; Renker, Dieter; Rohe, Tilman; Sibille, Jennifer; Bäni, Lukas; Bortignon, Pierluigi; Casal, Bruno; Chanon, Nicolas; Chen, Zhiling; Cittolin, Sergio; Deisher, Amanda; Dissertori, Günther; Dittmar, Michael; Eugster, Jürg; Freudenreich, Klaus; Grab, Christoph; Lecomte, Pierre; Lustermann, Werner; Marchica, Carmelo; Martinez Ruiz del Arbol, Pablo; Milenovic, Predrag; Mohr, Niklas; Moortgat, Filip; Nägeli, Christoph; Nef, Pascal; Nessi-Tedaldi, Francesca; Pape, Luc; Pauss, Felicitas; Peruzzi, Marco; Ronga, Frederic Jean; Rossini, Marco; Sala, Leonardo; Sanchez, Ann - Karin; Sawley, Marie-Christine; Starodumov, Andrei; Stieger, Benjamin; Takahashi, Maiko; Tauscher, Ludwig; Thea, Alessandro; Theofilatos, Konstantinos; Treille, Daniel; Urscheler, Christina; Wallny, Rainer; Weber, Hannsjoerg Artur; Wehrli, Lukas; Weng, Joanna; Aguilo, Ernest; Amsler, Claude; Chiochia, Vincenzo; De Visscher, Simon; Favaro, Carlotta; Ivova Rikova, Mirena; Millan Mejias, Barbara; Otiougova, Polina; Robmann, Peter; Schmidt, Alexander; Snoek, Hella; Verzetti, Mauro; Chang, Yuan-Hann; Chen, Kuan-Hsin; Kuo, Chia-Ming; Li, Syue-Wei; Lin, Willis; Liu, Zong-Kai; Lu, Yun-Ju; Mekterovic, Darko; Volpe, Roberta; Yu, Shin-Shan; Bartalini, Paolo; Chang, Paoti; Chang, You-Hao; Chang, Yu-Wei; Chao, Yuan; Chen, Kai-Feng; Dietz, Charles; Grundler, Ulysses; Hou, George Wei-Shu; Hsiung, Yee; Kao, Kai-Yi; Lei, Yeong-Jyi; Lu, Rong-Shyang; Shiu, Jing-Ge; Tzeng, Yeng-Ming; Wan, Xia; Wang, Minzu; Adiguzel, Aytul; Bakirci, Mustafa Numan; Cerci, Salim; Dozen, Candan; Dumanoglu, Isa; Eskut, Eda; Girgis, Semiray; Gokbulut, Gul; Hos, Ilknur; Kangal, Evrim Ersin; Kayis Topaksu, Aysel; Onengut, Gulsen; Ozdemir, Kadri; Ozturk, Sertac; Polatoz, Ayse; Sogut, Kenan; Sunar Cerci, Deniz; Tali, Bayram; Topakli, Huseyin; Uzun, Dilber; Vergili, Latife Nukhet; Vergili, Mehmet; Akin, Ilina Vasileva; Aliev, Takhmasib; Bilin, Bugra; Bilmis, Selcuk; Deniz, Muhammed; Gamsizkan, Halil; Guler, Ali Murat; Ocalan, Kadir; Ozpineci, Altug; Serin, Meltem; Sever, Ramazan; Surat, Ugur Emrah; Yalvac, Metin; Yildirim, Eda; Zeyrek, Mehmet; Deliomeroglu, Mehmet; Gülmez, Erhan; Isildak, Bora; Kaya, Mithat; Kaya, Ozlem; Özbek, Melih; Ozkorucuklu, Suat; Sonmez, Nasuf; Levchuk, Leonid; Bostock, Francis; Brooke, James John; Clement, Emyr; Cussans, David; Frazier, Robert; Goldstein, Joel; Grimes, Mark; Heath, Greg P; Heath, Helen F; Kreczko, Lukasz; Metson, Simon; Newbold, Dave M; Nirunpong, Kachanon; Poll, Anthony; Senkin, Sergey; Smith, Vincent J; Basso, Lorenzo; Bell, Ken W; Belyaev, Alexander; Brew, Christopher; Brown, Robert M; Camanzi, Barbara; Cockerill, David JA; Coughlan, John A; Harder, Kristian; Harper, Sam; Jackson, James; Kennedy, Bruce W; Olaiya, Emmanuel; Petyt, David; Radburn-Smith, Benjamin Charles; Shepherd-Themistocleous, Claire; Tomalin, Ian R; Womersley, William John; Bainbridge, Robert; Ball, Gordon; Beuselinck, Raymond; Buchmuller, Oliver; Colling, David; Cripps, Nicholas; Cutajar, Michael; Dauncey, Paul; Davies, Gavin; Della Negra, Michel; Ferguson, William; Fulcher, Jonathan; Futyan, David; Gilbert, Andrew; Guneratne Bryer, Arlo; Hall, Geoffrey; Hatherell, Zoe; Hays, Jonathan; Iles, Gregory; Jarvis, Martyn; Karapostoli, Georgia; Lyons, Louis; Magnan, Anne-Marie; Marrouche, Jad; Mathias, Bryn; Nandi, Robin; Nash, Jordan; Nikitenko, Alexander; Papageorgiou, Anastasios; Pesaresi, Mark; Petridis, Konstantinos; Pioppi, Michele; Raymond, David Mark; Rogerson, Samuel; Rompotis, Nikolaos; Rose, Andrew; Ryan, Matthew John; Seez, Christopher; Sharp, Peter; Sparrow, Alex; Tapper, Alexander; Tourneur, Stephane; Vazquez Acosta, Monica; Virdee, Tejinder; Wakefield, Stuart; Wardle, Nicholas; Wardrope, David; Whyntie, Tom; Barrett, Matthew; Chadwick, Matthew; Cole, Joanne; Hobson, Peter R; Khan, Akram; Kyberd, Paul; Leslie, Dawn; Martin, William; Reid, Ivan; Teodorescu, Liliana; Hatakeyama, Kenichi; Liu, Hongxuan; Scarborough, Tara; Henderson, Conor; Avetisyan, Aram; Bose, Tulika; Carrera Jarrin, Edgar; Fantasia, Cory; Heister, Arno; St John, Jason; Lawson, Philip; Lazic, Dragoslav; Rohlf, James; Sperka, David; Sulak, Lawrence; Bhattacharya, Saptaparna; Cutts, David; Ferapontov, Alexey; Heintz, Ulrich; Jabeen, Shabnam; Kukartsev, Gennadiy; Landsberg, Greg; Luk, Michael; Narain, Meenakshi; Nguyen, Duong; Segala, Michael; Sinthuprasith, Tutanon; Speer, Thomas; Tsang, Ka Vang; Breedon, Richard; Breto, Guillermo; Calderon De La Barca Sanchez, Manuel; Chauhan, Sushil; Chertok, Maxwell; Conway, John; Conway, Rylan; Cox, Peter Timothy; Dolen, James; Erbacher, Robin; Houtz, Rachel; Ko, Winston; Kopecky, Alexandra; Lander, Richard; Mall, Orpheus; Maruyama, Sho; Miceli, Tia; Pellett, Dave; Robles, Jorge; Rutherford, Britney; Searle, Matthew; Smith, John; Squires, Michael; Tripathi, Mani; Vasquez Sierra, Ricardo; Andreev, Valeri; Arisaka, Katsushi; Cline, David; Cousins, Robert; Duris, Joseph; Erhan, Samim; Everaerts, Pieter; Farrell, Chris; Hauser, Jay; Ignatenko, Mikhail; Jarvis, Chad; Plager, Charles; Rakness, Gregory; Schlein, Peter; Tucker, Jordan; Valuev, Vyacheslav; Weber, Matthias; Babb, John; Clare, Robert; Ellison, John Anthony; Gary, J William; Giordano, Ferdinando; Hanson, Gail; Jeng, Geng-Yuan; Kao, Shih-Chuan; Liu, Hongliang; Long, Owen Rosser; Luthra, Arun; Nguyen, Harold; Paramesvaran, Sudarshan; Sturdy, Jared; Sumowidagdo, Suharyo; Wilken, Rachel; Wimpenny, Stephen; Andrews, Warren; Branson, James G; Cerati, Giuseppe Benedetto; Evans, David; Golf, Frank; Holzner, André; Kelley, Ryan; Lebourgeois, Matthew; Letts, James; Mangano, Boris; Padhi, Sanjay; Palmer, Christopher; Petrucciani, Giovanni; Pi, Haifeng; Pieri, Marco; Ranieri, Riccardo; Sani, Matteo; Sfiligoi, Igor; Sharma, Vivek; Simon, Sean; Sudano, Elizabeth; Tadel, Matevz; Tu, Yanjun; Vartak, Adish; Wasserbaech, Steven; Würthwein, Frank; Yagil, Avraham; Yoo, Jaehyeok; Barge, Derek; Bellan, Riccardo; Campagnari, Claudio; D'Alfonso, Mariarosaria; Danielson, Thomas; Flowers, Kristen; Geffert, Paul; George, Christopher; Incandela, Joe; Justus, Christopher; Kalavase, Puneeth; Koay, Sue Ann; Kovalskyi, Dmytro; Krutelyov, Vyacheslav; Lowette, Steven; Mccoll, Nickolas; Mullin, Sam Daniel; Pavlunin, Viktor; Rebassoo, Finn; Ribnik, Jacob; Richman, Jeffrey; Rossin, Roberto; Stuart, David; To, Wing; Vlimant, Jean-Roch; West, Christopher; Apresyan, Artur; Bornheim, Adolf; Bunn, Julian; Chen, Yi; Di Marco, Emanuele; Duarte, Javier; Gataullin, Marat; Ma, Yousi; Mott, Alexander; Newman, Harvey B; Rogan, Christopher; Timciuc, Vladlen; Traczyk, Piotr; Veverka, Jan; Wilkinson, Richard; Yang, Yong; Zhu, Ren-Yuan; Akgun, Bora; Carroll, Ryan; Ferguson, Thomas; Iiyama, Yutaro; Jang, Dong Wook; Jun, Soon Yung; Liu, Yueh-Feng; Paulini, Manfred; Russ, James; Vogel, Helmut; Vorobiev, Igor; Cumalat, John Perry; Dinardo, Mauro Emanuele; Drell, Brian Robert; Edelmaier, Christopher; Ford, William T; Gaz, Alessandro; Heyburn, Bernadette; Luiggi Lopez, Eduardo; Nauenberg, Uriel; Smith, James; Stenson, Kevin; Ulmer, Keith; Wagner, Stephen Robert; Zang, Shi-Lei; Agostino, Lorenzo; Alexander, James; Chatterjee, Avishek; Eggert, Nicholas; Gibbons, Lawrence Kent; Heltsley, Brian; Hopkins, Walter; Khukhunaishvili, Aleko; Kreis, Benjamin; Nicolas Kaufman, Gala; Patterson, Juliet Ritchie; Puigh, Darren; Ryd, Anders; Salvati, Emmanuele; Shi, Xin; Sun, Werner; Teo, Wee Don; Thom, Julia; Thompson, Joshua; Vaughan, Jennifer; Weng, Yao; Winstrom, Lucas; Wittich, Peter; Biselli, Angela; Cirino, Guy; Winn, Dave; Abdullin, Salavat; Albrow, Michael; Anderson, Jacob; Apollinari, Giorgio; Atac, Muzaffer; Bakken, Jon Alan; Bauerdick, Lothar AT; Beretvas, Andrew; Berryhill, Jeffrey; Bhat, Pushpalatha C; Bloch, Ingo; Burkett, Kevin; Butler, Joel Nathan; Chetluru, Vasundhara; Cheung, Harry; Chlebana, Frank; Cihangir, Selcuk; Cooper, William; Eartly, David P; Elvira, Victor Daniel; Esen, Selda; Fisk, Ian; Freeman, Jim; Gao, Yanyan; Gottschalk, Erik; Green, Dan; Gutsche, Oliver; Hanlon, Jim; Harris, Robert M; Hirschauer, James; Hooberman, Benjamin; Jensen, Hans; Jindariani, Sergo; Johnson, Marvin; Joshi, Umesh; Klima, Boaz; Kousouris, Konstantinos; Kunori, Shuichi; Kwan, Simon; Leonidopoulos, Christos; Lincoln, Don; Lipton, Ron; Lykken, Joseph; Maeshima, Kaori; Marraffino, John Michael; Mason, David; McBride, Patricia; Miao, Ting; Mishra, Kalanand; Mrenna, Stephen; Musienko, Yuri; Newman-Holmes, Catherine; O'Dell, Vivian; Pivarski, James; Pordes, Ruth; Prokofyev, Oleg; Schwarz, Thomas; Sexton-Kennedy, Elizabeth; Sharma, Seema; Spalding, William J; Spiegel, Leonard; Tan, Ping; Taylor, Lucas; Tkaczyk, Slawek; Uplegger, Lorenzo; Vaandering, Eric Wayne; Vidal, Richard; Whitmore, Juliana; Wu, Weimin; Yang, Fan; Yumiceva, Francisco; Yun, Jae Chul; Acosta, Darin; Avery, Paul; Bourilkov, Dimitri; Chen, Mingshui; Das, Souvik; De Gruttola, Michele; Di Giovanni, Gian Piero; Dobur, Didar; Drozdetskiy, Alexey; Field, Richard D; Fisher, Matthew; Fu, Yu; Furic, Ivan-Kresimir; Gartner, Joseph; Goldberg, Sean; Hugon, Justin; Kim, Bockjoo; Konigsberg, Jacobo; Korytov, Andrey; Kropivnitskaya, Anna; Kypreos, Theodore; Low, Jia Fu; Matchev, Konstantin; Mitselmakher, Guenakh; Muniz, Lana; Park, Myeonghun; Remington, Ronald; Rinkevicius, Aurelijus; Schmitt, Michael Houston; Scurlock, Bobby; Sellers, Paul; Skhirtladze, Nikoloz; Snowball, Matthew; Wang, Dayong; Yelton, John; Zakaria, Mohammed; Gaultney, Vanessa; Lebolo, Luis Miguel; Linn, Stephan; Markowitz, Pete; Martinez, German; Rodriguez, Jorge Luis; Adams, Todd; Askew, Andrew; Bochenek, Joseph; Chen, Jie; Diamond, Brendan; Gleyzer, Sergei V; Haas, Jeff; Hagopian, Sharon; Hagopian, Vasken; Jenkins, Merrill; Johnson, Kurtis F; Prosper, Harrison; Sekmen, Sezen; Veeraraghavan, Venkatesh; Baarmand, Marc M; Dorney, Brian; Hohlmann, Marcus; Kalakhety, Himali; Vodopiyanov, Igor; Adams, Mark Raymond; Anghel, Ioana Maria; Apanasevich, Leonard; Bai, Yuting; Bazterra, Victor Eduardo; Betts, Russell Richard; Callner, Jeremy; Cavanaugh, Richard; Dragoiu, Cosmin; Gauthier, Lucie; Gerber, Cecilia Elena; Hofman, David Jonathan; Khalatyan, Samvel; Kunde, Gerd J; Lacroix, Florent; Malek, Magdalena; O'Brien, Christine; Silkworth, Christopher; Silvestre, Catherine; Strom, Derek; Varelas, Nikos; Akgun, Ugur; Albayrak, Elif Asli; Bilki, Burak; Clarida, Warren; Duru, Firdevs; Griffiths, Scott; Lae, Chung Khim; McCliment, Edward; Merlo, Jean-Pierre; Mermerkaya, Hamit; Mestvirishvili, Alexi; Moeller, Anthony; Nachtman, Jane; Newsom, Charles Ray; Norbeck, Edwin; Olson, Jonathan; Onel, Yasar; Ozok, Ferhat; Sen, Sercan; Tiras, Emrah; Wetzel, James; Yetkin, Taylan; Yi, Kai; Barnett, Bruce Arnold; Blumenfeld, Barry; Bolognesi, Sara; Bonato, Alessio; Eskew, Christopher; Fehling, David; Giurgiu, Gavril; Gritsan, Andrei; Guo, Zijin; Hu, Guofan; Maksimovic, Petar; Rappoccio, Salvatore; Swartz, Morris; Tran, Nhan Viet; Whitbeck, Andrew; Baringer, Philip; Bean, Alice; Benelli, Gabriele; Grachov, Oleg; Kenny Iii, Raymond Patrick; Murray, Michael; Noonan, Daniel; Sanders, Stephen; Stringer, Robert; Wood, Jeffrey Scott; Zhukova, Victoria; Barfuss, Anne-Fleur; Bolton, Tim; Chakaberia, Irakli; Ivanov, Andrew; Khalil, Sadia; Makouski, Mikhail; Maravin, Yurii; Shrestha, Shruti; Svintradze, Irakli; Gronberg, Jeffrey; Lange, David; Wright, Douglas; Baden, Drew; Boutemeur, Madjid; Calvert, Brian; Eno, Sarah Catherine; Gomez, Jaime; Hadley, Nicholas John; Kellogg, Richard G; Kirn, Malina; Lu, Ying; Mignerey, Alice; Peterman, Alison; Rossato, Kenneth; Rumerio, Paolo; Skuja, Andris; Temple, Jeffrey; Tonjes, Marguerite; Tonwar, Suresh C; Twedt, Elizabeth; Alver, Burak; Bauer, Gerry; Bendavid, Joshua; Busza, Wit; Butz, Erik; Cali, Ivan Amos; Chan, Matthew; Dutta, Valentina; Gomez Ceballos, Guillelmo; Goncharov, Maxim; Hahn, Kristan Allan; Harris, Philip; Kim, Yongsun; Klute, Markus; Lee, Yen-Jie; Li, Wei; Luckey, Paul David; Ma, Teng; Nahn, Steve; Paus, Christoph; Ralph, Duncan; Roland, Christof; Roland, Gunther; Rudolph, Matthew; Stephans, George; Stöckli, Fabian; Sumorok, Konstanty; Sung, Kevin; Velicanu, Dragos; Wenger, Edward Allen; Wolf, Roger; Wyslouch, Bolek; Xie, Si; Yang, Mingming; Yilmaz, Yetkin; Yoon, Sungho; Zanetti, Marco; Cooper, Seth; Cushman, Priscilla; Dahmes, Bryan; De Benedetti, Abraham; Franzoni, Giovanni; Gude, Alexander; Haupt, Jason; Klapoetke, Kevin; Kubota, Yuichi; Mans, Jeremy; Pastika, Nathaniel; Rekovic, Vladimir; Rusack, Roger; Sasseville, Michael; Singovsky, Alexander; Tambe, Norbert; Turkewitz, Jared; Cremaldi, Lucien Marcus; Godang, Romulus; Kroeger, Rob; Perera, Lalith; Rahmat, Rahmat; Sanders, David A; Summers, Don; Avdeeva, Ekaterina; Bloom, Kenneth; Bose, Suvadeep; Butt, Jamila; Claes, Daniel R; Dominguez, Aaron; Eads, Michael; Jindal, Pratima; Keller, Jason; Kravchenko, Ilya; Lazo-Flores, Jose; Malbouisson, Helena; Malik, Sudhir; Snow, Gregory R; Baur, Ulrich; Godshalk, Andrew; Iashvili, Ia; Jain, Supriya; Kharchilava, Avto; Kumar, Ashish; Smith, Kenneth; Wan, Zongru; Alverson, George; Barberis, Emanuela; Baumgartel, Darin; Chasco, Matthew; Trocino, Daniele; Wood, Darien; Zhang, Jinzhong; Anastassov, Anton; Kubik, Andrew; Mucia, Nicholas; Odell, Nathaniel; Ofierzynski, Radoslaw Adrian; Pollack, Brian; Pozdnyakov, Andrey; Schmitt, Michael Henry; Stoynev, Stoyan; Velasco, Mayda; Won, Steven; Antonelli, Louis; Berry, Douglas; Brinkerhoff, Andrew; Hildreth, Michael; Jessop, Colin; Karmgard, Daniel John; Kolb, Jeff; Kolberg, Ted; Lannon, Kevin; Luo, Wuming; Lynch, Sean; Marinelli, Nancy; Morse, David Michael; Pearson, Tessa; Ruchti, Randy; Slaunwhite, Jason; Valls, Nil; Wayne, Mitchell; Ziegler, Jill; Bylsma, Ben; Durkin, Lloyd Stanley; Hill, Christopher; Killewald, Phillip; Kotov, Khristian; Ling, Ta-Yung; Rodenburg, Marissa; Vuosalo, Carl; Williams, Grayson; Adam, Nadia; Berry, Edmund; Elmer, Peter; Gerbaudo, Davide; Halyo, Valerie; Hebda, Philip; Hunt, Adam; Laird, Edward; Lopes Pegna, David; Lujan, Paul; Marlow, Daniel; Medvedeva, Tatiana; Mooney, Michael; Olsen, James; Piroué, Pierre; Quan, Xiaohang; Raval, Amita; Saka, Halil; Stickland, David; Tully, Christopher; Werner, Jeremy Scott; Zuranski, Andrzej; Acosta, Jhon Gabriel; Huang, Xing Tao; Lopez, Angel; Mendez, Hector; Oliveros, Sandra; Ramirez Vargas, Juan Eduardo; Zatserklyaniy, Andriy; Alagoz, Enver; Barnes, Virgil E; Benedetti, Daniele; Bolla, Gino; Borrello, Laura; Bortoletto, Daniela; De Mattia, Marco; Everett, Adam; Gutay, Laszlo; Hu, Zhen; Jones, Matthew; Koybasi, Ozhan; Kress, Matthew; Laasanen, Alvin T; Leonardo, Nuno; Maroussov, Vassili; Merkel, Petra; Miller, David Harry; Neumeister, Norbert; Shipsey, Ian; Silvers, David; Svyatkovskiy, Alexey; Vidal Marono, Miguel; Yoo, Hwi Dong; Zablocki, Jakub; Zheng, Yu; Guragain, Samir; Parashar, Neeti; Adair, Antony; Boulahouache, Chaouki; Cuplov, Vesna; Ecklund, Karl Matthew; Geurts, Frank JM; Padley, Brian Paul; Redjimi, Radia; Roberts, Jay; Zabel, James; Betchart, Burton; Bodek, Arie; Chung, Yeon Sei; Covarelli, Roberto; de Barbaro, Pawel; Demina, Regina; Eshaq, Yossof; Flacher, Henning; Garcia-Bellido, Aran; Goldenzweig, Pablo; Gotra, Yury; Han, Jiyeon; Harel, Amnon; Miner, Daniel Carl; Petrillo, Gianluca; Sakumoto, Willis; Vishnevskiy, Dmitry; Zielinski, Marek; Bhatti, Anwar; Ciesielski, Robert; Demortier, Luc; Goulianos, Konstantin; Lungu, Gheorghe; Malik, Sarah; Mesropian, Christina; Arora, Sanjay; Atramentov, Oleksiy; Barker, Anthony; Chou, John Paul; Contreras-Campana, Christian; Contreras-Campana, Emmanuel; Duggan, Daniel; Ferencek, Dinko; Gershtein, Yuri; Gray, Richard; Halkiadakis, Eva; Hidas, Dean; Hits, Dmitry; Lath, Amitabh; Panwalkar, Shruti; Park, Michael; Patel, Rishi; Richards, Alan; Rose, Keith; Salur, Sevil; Schnetzer, Steve; Somalwar, Sunil; Stone, Robert; Thomas, Scott; Cerizza, Giordano; Hollingsworth, Matthew; Spanier, Stefan; Yang, Zong-Chang; York, Andrew; Eusebi, Ricardo; Flanagan, Will; Gilmore, Jason; Kamon, Teruki; Khotilovich, Vadim; Montalvo, Roy; Osipenkov, Ilya; Pakhotin, Yuriy; Perloff, Alexx; Roe, Jeffrey; Safonov, Alexei; Sengupta, Sinjini; Suarez, Indara; Tatarinov, Aysen; Toback, David; Akchurin, Nural; Bardak, Cemile; Damgov, Jordan; Dudero, Phillip Russell; Jeong, Chiyoung; Kovitanggoon, Kittikul; Lee, Sung Won; Libeiro, Terence; Mane, Poonam; Roh, Youn; Sill, Alan; Volobouev, Igor; Wigmans, Richard; Yazgan, Efe; Appelt, Eric; Brownson, Eric; Engh, Daniel; Florez, Carlos; Gabella, William; Gurrola, Alfredo; Issah, Michael; Johns, Willard; Johnston, Cody; Kurt, Pelin; Maguire, Charles; Melo, Andrew; Sheldon, Paul; Snook, Benjamin; Tuo, Shengquan; Velkovska, Julia; Arenton, Michael Wayne; Balazs, Michael; Boutle, Sarah; Conetti, Sergio; Cox, Bradley; Francis, Brian; Goadhouse, Stephen; Goodell, Joseph; Hirosky, Robert; Ledovskoy, Alexander; Lin, Chuanzhe; Neu, Christopher; Wood, John; Yohay, Rachel; Gollapinni, Sowjanya; Harr, Robert; Karchin, Paul Edmund; Kottachchi Kankanamge Don, Chamath; Lamichhane, Pramod; Mattson, Mark; Milstène, Caroline; Sakharov, Alexandre; Anderson, Michael; Bachtis, Michail; Belknap, Donald; Bellinger, James Nugent; Bernardini, Jacopo; Carlsmith, Duncan; Cepeda, Maria; Dasu, Sridhara; Efron, Jonathan; Friis, Evan; Gray, Lindsey; Grogg, Kira Suzanne; Grothe, Monika; Hall-Wilton, Richard; Herndon, Matthew; Hervé, Alain; Klabbers, Pamela; Klukas, Jeffrey; Lanaro, Armando; Lazaridis, Christos; Leonard, Jessica; Loveless, Richard; Mohapatra, Ajit; Ojalvo, Isabel; Pierro, Giuseppe Antonio; Ross, Ian; Savin, Alexander; Smith, Wesley H; Swanson, Joshua; Weinberg, Marc

2012-01-01

Measurements of jet characteristics from inclusive jet production in proton-proton collisions at a centre-of-mass energy of 7 TeV are presented. The data sample was collected with the CMS detector at the LHC during 2010 and corresponds to an integrated luminosity of 36 inverse picobarns. The mean charged hadron multiplicity, the differential and integral jet shape distributions, and two independent moments of the shape distributions are measured as functions of the jet transverse momentum for jets reconstructed with the anti-kT algorithm. The measured observables are corrected to the particle level and compared with predictions from various QCD Monte Carlo generators.

Sheet beam model for intense space charge: Application to Debye screening and the distribution of particle oscillation frequencies in a thermal equilibrium beam

Directory of Open Access Journals (Sweden)

Steven M. Lund

2011-05-01

Full Text Available A one-dimensional Vlasov-Poisson model for sheet beams is reviewed and extended to provide a simple framework for analysis of space-charge effects. Centroid and rms envelope equations including image-charge effects are derived and reasonable parameter equivalences with commonly employed 2D transverse models of unbunched beams are established. This sheet-beam model is then applied to analyze several problems of fundamental interest. A sheet-beam thermal equilibrium distribution in a continuous focusing channel is constructed and shown to have analogous properties to two- and three-dimensional thermal equilibrium models in terms of the equilibrium structure and Debye screening properties. The simpler formulation for sheet beams is exploited to explicitly calculate the distribution of particle oscillation frequencies within a thermal equilibrium beam. It is shown that as space-charge intensity increases, the frequency distribution becomes broad, suggesting that beams with strong space-charge can have improved stability relative to beams with weak space-charge.

PIC space-charge emission with finite Δt and Δz

International Nuclear Information System (INIS)

Hewett, D.W.; Chen, Yu-Jiuan.

1993-01-01

A new algorithm for space charge emission has been developed to provide the correct (to a few percent) Child-Langmuir steady-state current limits as the number of mesh points in the voltage gap drops to O(10). Further, the transient behavior of such flows compares well with idealized, analytic cases, lending confidence as we extend these algorithms into full RZ geometry with curved emitting surfaces to investigate transient characteristics of realistic injector designs

Space-charge effects in the Fermilab Main Ring at 8 GeV

International Nuclear Information System (INIS)

Mane, S.R.

1989-03-01

I use computer tracking to investigate the effects of space-charge on particle motion in the Fermilab Main Ring at p = 8 GeV/c. The results are found to agree with the Laslett tuneshift formula. Simple model cases are also studied to speed up the tracking. The effects of synchrotron oscillations, via tune modulation and dispersion, are included. 2 refs., 5 figs

Temperature Condition and Spherical Shell Shape Variation of Space Gauge-Alignment Spacecraft

Directory of Open Access Journals (Sweden)

V. S. Zarubin

2016-01-01

Full Text Available A high precision spherical shell is one of the geometrical shape embodiments of a gaugealignment spacecraft to determine and control a radar channel energy potential of the ground-based complex for the traffic control of space objects. Passive relays of signals and some types of smallsized instrumentation standard reflectors used for radar gauge and alignment have the same shape. Orbits of the considered spacecraft can be either circular with a height of about 1000 km, including those close to the polar, or elliptical with an apogee of up to 2200 km.In case there is no thermal control system in spacecrafts of these types the solar radiation is a major factor to define the thermal state of a spherical shell in the illuminated orbit area. With the shell in fixed position with respect to direction towards the Sun an arising uneven temperature distribution over its surface leads to variation of the spherically ideal shell shape, which may affect the functional characteristics of the spacecraft. The shell rotation about an axis perpendicular to the direction towards the Sun may reduce an unevenness degree of the temperature distribution.The uneven temperature distribution over the spherical shell surface in conditions of the lowEarth space and this unevenness impact on the shell shape variation against its spherical shape can be quantively estimated by the appropriate methods of mathematical modeling using modification of a previously developed mathematical model to describe steady temperature state of such shell on the low-Earth orbit. The paper considers the shell made from a polymeric composite material. Its original spherical shape is defined by rather low internal pressure. It is assumed that equipment in the shell, if any, is quite small-sized. This allows us to ignore its impact on the radiative transfer in the shell cavity. Along with defining the steady temperature distribution over the shell surface at its fixed orientation with respect to

Gender and the Telephone: Voice and Emotions Shaping and Gendering Space

Directory of Open Access Journals (Sweden)

Mona Livholts

2013-01-01

Full Text Available In the field of communication studies, the topic of telephony and the gendering of space via voice and emotions has received limited attention. The focus of this article is how telephone conversations are mediated by voice and emotions, which in turn shape and gender social space. The methodology is a collaborative autoethnographic design based on diary notes and memory work. Two central themes emerge from the findings that explain how space becomes gendered when using the telephone: (a the voice and relations of power, and (b the interstices between work, caring, and the telephone. Our findings reveal the central role of work and caring and how these spaces constantly are being traversed and transformed as the mobile phone becomes an important appendage for sensory perceptions of hearing/listening/voice. We argue that these themes point toward the crucial impact of emotions in the construction of multiple and gendered spatialities of telephony.

Space-charge flow in a non-cylindrically symmetric diode

International Nuclear Information System (INIS)

Quintenz, J.P.; Poukey, J.W.

1976-01-01

The one-dimensional cylindrical space-charge-limited emission and flow results of Langmuir and Blodgett are extended to the two-dimensional (r-theta) non-symmetric case by solving a fluid model numerically. It is found that particle beams thus generated can be controlled by suitable adjustment of the applied potentials and cylinder radii. A particle code has been modified to treat razor blade cathodes by including a simplified model for the blade emission. Numerical results are compared with experimental data. These results indicate that beams produced by razor blades pinch less tightly than those from block cathodes, but in some cases may still pinch enough to be interesting

Analytically continued Fock space multi-reference coupled-cluster theory: Application to the shape resonance

International Nuclear Information System (INIS)

Pal, Sourav; Sajeev, Y.; Vaval, Nayana

2006-01-01

The Fock space multi-reference coupled-cluster (FSMRCC) method is used for the study of the shape resonance energy and width in an electron-atom/molecule collision. The procedure is based upon combining a complex absorbing potential (CAP) with FSMRCC theory. Accurate resonance parameters are obtained by solving a small non-Hermitian eigen-value problem. We study the shape resonances in e - -C 2 H 4 and e - -Mg

Space-charge effects on the propagation of hollow electron beams

International Nuclear Information System (INIS)

Barroso, J.J.; Stellati, C.

1994-01-01

The dynamics of hollow electron beams with gyro motion propagating down a cylindrical drift tube is analysed on the basis of a non-adiabatic-gun-generated laminar beam. Due to the action of beam's self-space charge field, the transverse velocity spread has an oscillatory behavior along the drift tube wherein the spatial auto modulation period shortens with increasing current. Numerical simulation results indicate that even at a 10 A beam current, the resulting transverse velocity spread is still less than the spread for a zero beam current. (author). 5 refs, 3 figs

Program NAJOCSC and space charge effect simulation in C01

International Nuclear Information System (INIS)

Tang, J.Y.; Chabert, A.; Baron, E.

1999-01-01

During the beam tests of the THI project at GANIL, it was found it difficult to increase the beam power above 2 kW at CSS2 extraction. The space charge effect (abbreviated as S.C. effect) in cyclotrons is suspected to play some role in the phenomenon, especially the longitudinal S.C. one and also the coupling between longitudinal and radial motions. The injector cyclotron C01 is studied, and the role played by the S.C. effect in this cyclotron in the THI case is investigated by a simulation method. (K.A.)

Simulations of space charge neutralization in a magnetized electron cooler

Energy Technology Data Exchange (ETDEWEB)

Gerity, James [Texas A-M; McIntyre, Peter M. [Texas A-M; Bruhwiler, David Leslie [RadiaSoft, Boulder; Hall, Christopher [RadiaSoft, Boulder; Moens, Vince Jan [Ecole Polytechnique, Lausanne; Park, Chong Shik [Fermilab; Stancari, Giulio [Fermilab

2017-02-02

Magnetized electron cooling at relativistic energies and Ampere scale current is essential to achieve the proposed ion luminosities in a future electron-ion collider (EIC). Neutralization of the space charge in such a cooler can significantly increase the magnetized dynamic friction and, hence, the cooling rate. The Warp framework is being used to simulate magnetized electron beam dynamics during and after the build-up of neutralizing ions, via ionization of residual gas in the cooler. The design follows previous experiments at Fermilab as a verification case. We also discuss the relevance to EIC designs.

Thermal blurring effects on fluctuations of conserved charges in rapidity space

Energy Technology Data Exchange (ETDEWEB)

Asakawa, M.; Kitazawa, M.; Onishi, Y.; Sakaida, M.

2016-12-15

We argue that the diffusion in the hadron phase and the thermal blurring at thermal freezeout affect observed conserved charge fluctuations considerably in relativistic heavy ion collisions, and show that their effects are of similar order at RHIC and LHC, and thus equally important in understanding experimental data. We also argue that, in order to disentangle them and obtain the initial state charge fluctuations, which we are interested in, it is crucial to measure their dependence on the rapidity window size. In the energy range of the beam energy scan program at RHIC, the diffusion effect would be less important because of the shorter duration of the hadron phase, but the importance of thermal blurring is not reduced. In addition, it is necessary to take account of the complex correspondence between the space-time rapidity and rapidity of observed particles, there.

Effects of Hydrogen Charging on the Phase Transformation of Martensitic NiTi Shape Memory Alloy Wires

Science.gov (United States)

Snir, Yoav; Carl, Matthew; Ley, Nathan A.; Young, Marcus L.

2017-12-01

Ti-rich martensitic NiTi shape memory alloy (SMA) wires of 0.5 mm diameter were tested under hydrogen-charging conditions to reveal the effects on phase transformation. Hydrogen charging was performed by immersion testing for several durations. The SMA wires were characterized by differential scanning calorimetry (DSC), scanning electron microscopy with energy dispersive spectroscopy, and synchrotron radiation X-ray diffraction (SR-XRD) for the the as-received, polished, and hydrogen-charged conditions. The DSC revealed the phase-transformation behavior of the NiTi SMA wires. Single and triple heating/cooling cycles in the DSC show the relationship between hydrogen and temperature on the material. Five distinct peaks (peaks I-V) are observed during heating/cooling in the DSC. Peak I corresponds to the martensite-to-austenite (M → A) transformation. Peaks II, III, and IV are related to hydrogen charging. Peak II appears at about 210-230 °C, while peaks III and IV appear at about 350 and 440 °C, respectively. These higher temperature peaks, peaks II-IV, were observed for the first time for a martensitic NiTi SMA due to the large temperature range covered using the DSC. Only one peak (peak V) appears during cooling and corresponds to the austenite-to-martensite transformation peak. Ex situ and in situ SR-XRD revealed the phases and the crystallographic relationship to peaks I-V in the DSC.

Beyond Shape and Gravity: Children's Ideas about the Earth in Space Reconsidered

Science.gov (United States)

Sharp, John G.; Sharp, Jane C.

2007-01-01

Children's ideas about the Earth in space have been of interest to science educators and cognitive psychologists for some time. By focusing almost exclusively on shape and gravity alone, however, other important Earth attributes have been largely neglected or overlooked. Findings from a quasi-experimental study of knowledge acquisition and concept…

Spinorial charges and their role in the fusion of internal and space-time symmetries

International Nuclear Information System (INIS)

Daniel, M.; Ktorides, C.N.

1976-01-01

The advent of supersymmetry immediately led to speculations that a non-trivial mixing of internal and space-time symmetries could be achieved within its framework. In fact, the well-known no-go theorems do not apply to the supersymmetry algebra due to the presence, in the latter, of (anticommuting) spinorial charges. However, not until the recent work of Haag, Lopuszanski and Sohnius did a clearcut picture emerge as to how the aforementioned nontrivial mixing can take place. Most notably, the presence of the conformal algebra within the supersymmetry algebra turns out to be vital. The findings of Haag et al. are solidified through an explicit construction which uses as underlying space the pseudo-Euclidean space E(4, 2), i.e. the space for which the conformal group is the group of rotations, and which employs as main tools the spinors associated with the space E(4, 2). The algebro-geometric approach of Cartan is followed in order to understand both the introduction and the properties of these spinors. In this manner, many insights are gained regarding the mathematical foundations of supersymmetry. Thus, the emergence of the anticommutator, rather than the commutator, among spinor charges is fully understood as a natural algebraic consequence and not as an a priori given fact. In addition, it is clearly seen how an (internal) unitary symmetry group can make its appearance within the supersymmetry scheme and verify, via this explicit construction, the results of Haag et al. (Auth.)

Optical method for mapping the transverse phase space of a charged particle beam

International Nuclear Information System (INIS)

Fiorito, R.B.; Shkvarunets, A.G.; O'Shea, P.G.

2002-01-01

We are developing an all optical method to map the transverse phase space map of a charged particle beam. Our technique employs OTR interferometry (OTRI) in combination with a scanning pinhole to make local orthogonal (x,y) divergence and trajectory angle measurements as function of position within the transverse profile of the beam. The localized data allows a reconstruction of the horizontal and vertical phase spaces of the beam. We have also demonstrated how single and multiple pinholes can in principle be used to make such measurements simultaneously

Cold-fluid theory of equilibrium and stability of a high-intensity periodically twisted ellipse-shaped charged-particle beam

Directory of Open Access Journals (Sweden)

Jing Zhou

2006-03-01

Full Text Available It is shown that there exists an exact paraxial cold-fluid equilibrium of a high-intensity, space-charge-dominated charged-particle beam with a periodically twisted elliptic cross section in a nonaxisymmetric periodic magnetic field. Generalized envelope equations, which determine the beam envelopes, ellipse orientation, density, and internal flow velocity profiles, are derived. Nonrelativistic and relativistic examples of such beam equilibria are presented. The equilibrium and stability of such beams are demonstrated by self-consistent particle-in-cell (PIC simulations.

Theory of accelerated orbits and space charge effects in an AVF cyclotron

International Nuclear Information System (INIS)

Kleeven, W.J.G.M.

1988-01-01

In the first part of this thesis the influence of the accelerating electric field upon the motion of particles in a cyclotron is studied. A general relativistic Hamiltonian theory is derived which allows for a simultaneous study of the transverse and longitudinal motion as well as the coupling between both motions. It includes azimuthally varying magnetic fields and therefore describes phenomena which are due to the interfering influences of a given geometrical dee system with the azimuthally varying part of the magnetic field. As an example the electric gap crossing resonance is treated. The second part deals with space charge effects in a AVF cyclotron. The properties of the bunch, like the sizes, emittances and momentum spread, are represented in terms of second order moments of the phase space distribution function, and two sets of differential equations are derived which describe the time evolution of these moments under space charge conditions. The model takes into account the coupling between the longitudinal and radial motion, and the fact that the revolution frequency of the particles is independent of their energy. The analytical models developed can be applied to a given cyclotron by adopting the relevant parameters. Some calculations are presented for the small 3 MeV Iscochroneous Low Energy Cyclotron ILEC which is presently under construction at the Eindhoven University. Also some attention to the construction of this machine is given. (H.W.). 49 refs.; 37 figs

Fold and Fit: Space Conserving Shape Editing

KAUST Repository

Ibrahim, Mohamed

2017-09-01

We present a framework that folds man-made objects in a structure-aware manner for space-conserving storage and transportation. Given a segmented 3D mesh of a man-made object, our framework jointly optimizes for joint locations, the folding order, and folding angles for each part of the model, enabling it to transform into a spatially efficient configuration while keeping its original functionality as intact as possible. That is, if a model is supposed to withstand several forces in its initial state to serve its functionality, our framework places the joints between the parts of the model such that the model can withstand forces with magnitudes that are comparable to the magnitudes applied on the unedited model. Furthermore, if the folded shape is not compact, our framework proposes further segmentation of the model to improve its compactness in its folded state.

Space charge and wake field analysis for a high brightness electron source

International Nuclear Information System (INIS)

Parsa, Z.

1991-01-01

We present a brief overview of the formalism used, and some simulation results for transverse and longitudinal motion of a bunch of particles moving through a cavity (e.g., the Brookhaven National Laboratory high brightness photocathode gun), including effects of the accelerating field, space charge forces (e.g., arising from the interaction of the cavity surface and the self field of the bunch). 3 refs., 12 figs

Emittance growth due to static and radiative space charge forces in an electron bunch compressor

Science.gov (United States)

Talman, Richard; Malitsky, Nikolay; Stulle, Frank

2009-01-01

Evolution of short intense electron bunches passing through bunch-compressing beam lines is studied using the UAL (Unified Accelerator Libraries) string space charge formulation [R. Talman, Phys. Rev. ST Accel. Beams 7, 100701 (2004)PRABFM1098-440210.1103/PhysRevSTAB.7.100701; N. Malitsky and R. Talman, in Proceedings of the 9th European Particle Accelerator Conference, Lucerne, 2004 (EPS-AG, Lucerne, 2004); R. Talman, Accelerator X-Ray Sources (Wiley-VCH, Weinheim, 2006), Chap. 13]. Three major configurations are studied, with the first most important and studied in greatest detail (because actual experimental results are available and the same results have been simulated with other codes): (i) Experimental bunch compression results were obtained at CTF-II, the CERN test facility for the “Compact Linear Collider” using electrons of about 40 MeV. Previous simulations of these results have been performed (using TraFiC4* [A. Kabel , Nucl. Instrum. Methods Phys. Res., Sect. A 455, 185 (2000)NIMAER0168-900210.1016/S0168-9002(00)00729-4] and ELEGANT [M. Borland, Argonne National Laboratory Report No. LS-287, 2000]). All three simulations are in fair agreement with the data except that the UAL simulation predicts a substantial dependence of horizontal emittance γx on beam width (as controlled by the lattice βx function) at the compressor location. This is consistent with the experimental observations, but inconsistent with other simulations. Excellent agreement concerning dependence of bunch energy loss on bunch length and magnetic field strength [L. Groening , in Proceedings of the Particle Accelerator Conference, Chicago, IL, 2001 (IEEE, New York, 2001), http://groening.home.cern/groening/csr_00.htm] confirms our understanding of the role played by coherent synchrotron radiation (CSR). (ii) A controlled comparison is made between the predictions of the UAL code and those of CSRTrack [M. Dohlus and T. Limberg, in Proceedings of the 2004 FEL Conference, pp. 18

Emittance growth due to static and radiative space charge forces in an electron bunch compressor

Directory of Open Access Journals (Sweden)

Richard Talman

2009-01-01

Full Text Available Evolution of short intense electron bunches passing through bunch-compressing beam lines is studied using the UAL (Unified Accelerator Libraries string space charge formulation [R. Talman, Phys. Rev. ST Accel. Beams 7, 100701 (2004PRABFM1098-440210.1103/PhysRevSTAB.7.100701; N. Malitsky and R. Talman, in Proceedings of the 9th European Particle Accelerator Conference, Lucerne, 2004 (EPS-AG, Lucerne, 2004; R. Talman, Accelerator X-Ray Sources (Wiley-VCH, Weinheim, 2006, Chap. 13]. Three major configurations are studied, with the first most important and studied in greatest detail (because actual experimental results are available and the same results have been simulated with other codes: (i Experimental bunch compression results were obtained at CTF-II, the CERN test facility for the “Compact Linear Collider” using electrons of about 40 MeV. Previous simulations of these results have been performed (using TraFiC4* [A. Kabel et al., Nucl. Instrum. Methods Phys. Res., Sect. A 455, 185 (2000NIMAER0168-900210.1016/S0168-9002(0000729-4] and ELEGANT [M. Borland, Argonne National Laboratory Report No. LS-287, 2000]. All three simulations are in fair agreement with the data except that the UAL simulation predicts a substantial dependence of horizontal emittance ϵ_{x} on beam width (as controlled by the lattice β_{x} function at the compressor location. This is consistent with the experimental observations, but inconsistent with other simulations. Excellent agreement concerning dependence of bunch energy loss on bunch length and magnetic field strength [L. Groening et al., in Proceedings of the Particle Accelerator Conference, Chicago, IL, 2001 (IEEE, New York, 2001, http://groening.home.cern/groening/csr_00.htm] confirms our understanding of the role played by coherent synchrotron radiation (CSR. (ii A controlled comparison is made between the predictions of the UAL code and those of CSRTrack [M. Dohlus and T. Limberg, in Proceedings of the

Extraction of space-charge-dominated ion beams from an ECR ion source: Theory and simulation

Science.gov (United States)

Alton, G. D.; Bilheux, H.

2004-05-01

Extraction of high quality space-charge-dominated ion beams from plasma ion sources constitutes an optimization problem centered about finding an optimal concave plasma emission boundary that minimizes half-angular divergence for a given charge state, independent of the presence or lack thereof of a magnetic field in the extraction region. The curvature of the emission boundary acts to converge/diverge the low velocity beam during extraction. Beams of highest quality are extracted whenever the half-angular divergence, ω, is minimized. Under minimum half-angular divergence conditions, the plasma emission boundary has an optimum curvature and the perveance, P, current density, j+ext, and extraction gap, d, have optimum values for a given charge state, q. Optimum values for each of the independent variables (P, j+ext and d) are found to be in close agreement with those derived from elementary analytical theory for extraction with a simple two-electrode extraction system, independent of the presence of a magnetic field. The magnetic field only increases the emittances of beams through additional aberrational effects caused by increased angular divergences through coupling of the longitudinal to the transverse velocity components of particles as they pass though the mirror region of the electron cyclotron resonance (ECR) ion source. This article reviews the underlying theory of elementary extraction optics and presents results derived from simulation studies of extraction of space-charge dominated heavy-ion beams of varying mass, charge state, and intensity from an ECR ion source with emphasis on magnetic field induced effects.

Extraction of space-charge-dominated ion beams from an ECR ion source: Theory and simulation

International Nuclear Information System (INIS)

Alton, G.D.; Bilheux, H.

2004-01-01

Extraction of high quality space-charge-dominated ion beams from plasma ion sources constitutes an optimization problem centered about finding an optimal concave plasma emission boundary that minimizes half-angular divergence for a given charge state, independent of the presence or lack thereof of a magnetic field in the extraction region. The curvature of the emission boundary acts to converge/diverge the low velocity beam during extraction. Beams of highest quality are extracted whenever the half-angular divergence, ω, is minimized. Under minimum half-angular divergence conditions, the plasma emission boundary has an optimum curvature and the perveance, P, current density, j +ext , and extraction gap, d, have optimum values for a given charge state, q. Optimum values for each of the independent variables (P, j +ext and d) are found to be in close agreement with those derived from elementary analytical theory for extraction with a simple two-electrode extraction system, independent of the presence of a magnetic field. The magnetic field only increases the emittances of beams through additional aberrational effects caused by increased angular divergences through coupling of the longitudinal to the transverse velocity components of particles as they pass though the mirror region of the electron cyclotron resonance (ECR) ion source. This article reviews the underlying theory of elementary extraction optics and presents results derived from simulation studies of extraction of space-charge dominated heavy-ion beams of varying mass, charge state, and intensity from an ECR ion source with emphasis on magnetic field induced effects

Space charge profiles in low density polyethylene samples containing a permittivity/conductivity gradient

DEFF Research Database (Denmark)

Bambery, K.R.; Fleming, R.J.; Holbøll, Joachim

2001-01-01

.5×107 V m-1. Current density was also measured as a function of temperature and field. Space charge due exclusively to the temperature gradient was detected, with density of order 0.01 C m-3. The activation energy associated with the transport of electrons through the bulk was calculated as 0.09 e...

Through space and through bridge channels of charge transfer at p-n nano-junctions: A DFT study

Energy Technology Data Exchange (ETDEWEB)

Dandu, Naveen [Department of Chemistry and Biochemistry, NDSU, Fargo, ND 58108 (United States); Tretiak, Sergei [Theoretical Division, Center for Nonlinear Studies (CNLS) and Center for Integrated Nanotechnologies (CINT), Los Alamos National Laboratory, Los Alamos, 57069, NM 87454 (United States); Kilina, Svetlana [Department of Chemistry and Biochemistry, NDSU, Fargo, ND 58108 (United States); Kilin, Dmitri, E-mail: Dmitri.Kilin@ndsu.edu [Department of Chemistry and Biochemistry, NDSU, Fargo, ND 58108 (United States)

2016-12-20

Highlights: • Properties of interacting QDs depend on the fashion of interaction: through-bond or through-space. • The disconnected and undoped dimer models shows FÓ§rster band formation. • Dimer models with some doping exhibit degenerate charge-transfer excitons. • p- and n-doped qds shows polarization at the interface. • A photoexcitation polarizes p-n interface, in relation to phototovoltaic effect. - Abstract: Details of charge density distribution at p-n nano interface are analyzed with density functional theory techniques using model system of dimers of doped silicon quantum dots interacting through bond and through space. Spatial distributions of transition densities between the ground and excited states suggest the character of essential electronic excitations, which have a FÓ§rster, bound, unbound, or charge transfer character. A redistribution of electronic density from n-impurities to p-impurities results in a ground state polarization and creates an offset of energies of the bands localized on p-doped quantum dot and the bands localized on n-doped quantum dot. Although impurities contribute very few orbitals to the total density, a ground state charge redistribution and polarization are both responsible for the presence of a large number of charge transfer excitations involving solely silicon orbitals.

Breakdown of a Space Charge Limited Regime of a Sheath in a Weakly Collisional Plasma Bounded by Walls with Secondary Electron Emission

International Nuclear Information System (INIS)

Sydorenko, D.; Smolyakov, A.; Kaganovich, I.; Raitses, Y.

2009-01-01

A new regime of plasma-wall interaction is identified in particle-in-cell simulations of a hot plasma bounded by walls with secondary electron emission. Such a plasma has a strongly non-Maxwellian electron velocity distribution function and consists of bulk plasma electrons and beams of secondary electrons. In the new regime, the plasma sheath is not in a steady space charge limited state even though the secondary electron emission produced by the plasma bulk electrons is so intense that the corresponding partial emission coefficient exceeds unity. Instead, the plasma-sheath system performs relaxation oscillations by switching quasiperiodically between the space charge limited and non-space-charge limited states.

Quasinormal modes and thermodynamics of linearly charged BTZ black holes in massive gravity in (anti) de Sitter space-time

Energy Technology Data Exchange (ETDEWEB)

Prasia, P.; Kuriakose, V.C. [Cochin University of Science and Technology, Department of Physics, Kochi (India)

2017-01-15

In this work we study the Quasi-Normal Modes (QNMs) under massless scalar perturbations and the thermodynamics of linearly charged BTZ black holes in massive gravity in the (Anti)de Sitter ((A)dS) space-time. It is found that the behavior of QNMs changes with the massive parameter of the graviton and also with the charge of the black hole. The thermodynamics of such black holes in the (A)dS space-time is also analyzed in detail. The behavior of specific heat with temperature for such black holes gives an indication of a phase transition that depends on the massive parameter of the graviton and also on the charge of the black hole. (orig.)

New Method for Shallow and Deep Trap Distribution Analysis in Oil Impregnated Insulation Paper Based on the Space Charge Detrapping

Directory of Open Access Journals (Sweden)

Jian Hao

2018-01-01

Full Text Available Space charge has close relation with the trap distribution in the insulation material. The phenomenon of charges trapping and detrapping has attracted significant attention in recent years. Space charge and trap parameters are effective parameters for assessing the ageing condition of the insulation material qualitatively. In this paper, a new method for calculating trap distribution based on the double exponential fitting analysis of charge decay process and its application on characterizing the trap distribution of oil impregnated insulation paper was investigated. When compared with the common first order exponential fitting analysis method, the improved dual-level trap method could obtain the energy level range and density of both shallow traps and deep traps, simultaneously. Space charge decay process analysis of the insulation paper immersed with new oil and aged oil shows that the improved trap distribution calculation method can distinguish the physical defects and chemical defects. The trap density shows an increasing trend with the oil ageing, especially for the deep traps mainly related to chemical defects. The greater the energy could be filled by the traps, the larger amount of charges could be trapped, especially under higher electric field strength. The deep trap energy level and trap density could be used to characterize ageing. When one evaluates the ageing condition of oil-paper insulation using trap distribution parameters, the influence of oil performance should not be ignored.

Space-charge-limited ion flow through an ionizing neutral layer

International Nuclear Information System (INIS)

Duvall, R.E.; Litwin, C.; Maron, Y.

1993-01-01

Space-charge-limited ion flow through an ionizing layer of neutral atoms is studied. The ion flow is between two parallel conducting plates (anode and cathode) with an externally applied voltage between them. An expanding layer of neutral atoms is adjacent to the anode surface, extending a finite distance into the anode--cathode gap. All ions originate either from the anode surface or from the ionization of neutrals; electrons originate only from ionization. Electrons are strongly magnetized by an externally applied, time-independent direct current (dc) magnetic field directed across the ion flow. The ions are unmagnetized, all motion being perpendicular to the conducting plates. Two different models of the anode layer were used to analyze this problem: a multifluid steady-state model and a single fluid time-dependent model. From both models it was found that the anode surface becomes shielded after the ion flux from the ionizing layer becomes larger than the space-charge-limited flux of the reduced gap between the neutral layer and cathode. Comparison was made between the time-dependent model and results from magnetically insulated ion beam diode (MID) experiments. Using an initial areal density of neutral hydrogen and carbon equal to the final observed electron areal density, comparison was made between calculated plasma shielding times and upper bounds on the shielding time observed in experiments. It was found that a layer of neutral hydrogen must contain a minimum of 15% carbon (by number density) to explain the rapid electric field screening observed in experiments

Transport and matching of low energy space charge dominated beams

International Nuclear Information System (INIS)

Pandit, V.S.

2013-01-01

The transport and matching of low energy high intensity beams from the ion source to the subsequent accelerating structure are of considerable interest in recent years for variety of applications such as Accelerator driven system (ADSS), transmutation of nuclear waste, spallation neutron sources etc. It is essential to perform detailed simulations with experimentation to predict the beam evolution in the presence of nonlinear self as well as external fields before the design of the next accelerating structure is finalized. In order to study and settle various physics and technical issues related with transport of space charge dominated beams we have developed a 2.45 GHz microwave ion source at VECC which is now delivering more than 10 mA proton beam current at 80 keV. We have successfully transported well collimated 8 mA proton beam through the solenoid based 3 meter long transport line and studied various beam properties. We have also studied the transport of beam through spiral inflector at low beam current ∼ 1mA. In this article we will discuss the beam transport issues and describe a technique for simulation of beam envelopes in presence of linear space charge effects. We use canonical description of the motion of a single particle and then obtain first order differential equations for evolution of the moments of beam ensemble by assuming uniform distribution of the beam. We will also discuss the methodology used in the simulations to understand the observed beam behaviour during transport. (author)

Role of space--time topology in quantum phenomena: Superselection of charge and emergence of nontrivial vacua

International Nuclear Information System (INIS)

Ashtekar, A.; Sen, A.

1980-01-01

Schwarzschild--Kruskal space--time admits a two-parameter family of everywhere regular, static, source-free Maxwell fields. It is shown that there exists a corresponding two-parameter family of unitarily inequivalent representations of the canonical commutation relations. Elements of the underlying Hilbert space may be interpreted as ''quantum fluctuations of the Maxwell field off nontrivial classical vacua.'' The representation corresponding to the ''trivial'' sector: i.e., the zero classical solution: is the usual Fock representation. All others are ''non-Fock.'' In particular, in all other sectors, the Maxwell field develops a nonzero vacuum expectation value. The parameters labelling the family can be interpreted as electric and magnetic charges. Therefore, unitary inequivalence naturally leads to superselection rules for these charges. These features arise in spite of the linearity of field equations only because the space--time topology is ''nontrivial.'' Also, because of linearity, an exact analysis is possible at the quantum level; recourse to perturbation theory is unnecessary

A Gauss-Newton method for the integration of spatial normal fields in shape Space

KAUST Repository

Balzer, Jonathan

2011-01-01

to solving a nonlinear least-squares problem in shape space. Previously, the corresponding minimization has been performed by gradient descent, which suffers from slow convergence and susceptibility to local minima. Newton-type methods, although significantly

Space charge calibration of the ALICE TPC operated with an open gating grid

Energy Technology Data Exchange (ETDEWEB)

Hellbaer, Ernst [Institut fuer Kernphysik, Goethe-Universitaet Frankfurt (Germany); Ivanov, Marian [GSI (Germany); Wiechula, Jens [Universitaet Tuebingen (Germany); Collaboration: ALICE-Collaboration

2015-07-01

The Time Projection Chamber (TPC) is the main particle identification detector of the ALICE experiment at the CERN LHC. High interaction rates of 50 kHz in Pb-Pb during the Run 3 period after 2020 require a major upgrade of the TPC readout. The currently used Multiwire Proportional Chambers (MWPCs) will be replaced by readout chambers (ROCs) based on Gas Electron Multiplier (GEM) technology which will be operated in a continuous mode. While the gating grid of the MWPCs prevents the positive ions of the amplification region from entering the drift volume, the GEM-based ROCs will introduce an ion backflow (IBF) of about 1%. In combination with the high-luminosity environment, this amount of back-drifting ions results in a considerable space charge density which distorts the drift path of the primary ionisation electrons significantly. In order to still provide a high tracking efficiency and cluster-to-track association, an efficient calibration scheme will be implemented. As a test ground for the new calibration scheme, pp collision data was taken during Run 1 with the gating grid operated in a transparent mode allowing the ions to enter the drift volume. The measured space point distortions due to the space charge are presented together with the corrected data and compared to simulations for Run 3.

First result of net-charge jet-correlations from STAR

International Nuclear Information System (INIS)

Wang, Q.

2011-01-01

We presented results on azimuthal correlation of net-charge with high ρ T trigger particles. It is found that the net-charge correlation shape is similar to that of total-charge. On the near-side, the net-charge and total-charge ρ T spectra have similar shape and both are harder than the inclusives. On the away-side, the correlated spectra are not much harder than the inclusives, and the net-charge/total-charge ratio increases with ρ T and is similar to the inclusive ratio. (author)

Vacuum polarization and topological self-interaction of a charge in multiconic space

International Nuclear Information System (INIS)

Gal'tsov, D.V.; Grats, Y.V.; Lavrent'ev, A.B.

1995-01-01

The behavior of classical and quantized massless scalar fields in n-dimensional multiconic space-time is considered. An expression for the Euclidean Green's function is obtained using the methods of perturbation theory. It is shown that a nontrivial topology of the space distorts the electrostatic field of a pointlike charge; as a result, the self-energy of the particle assumes a nonzero value, and a force of topological self-interaction arises. Similarly, a change in the spectrum of vacuum fluctuations of a quantized scalar field leads to nonzero vacuum expectation values left-angle φ 2 right-angle vac and left-angle T μv right-angle va and gives rise to vacuum attraction between parallel cosmic strings. 28 refs

Electrostatic energy and screened charge interaction near the surface of metals with different Fermi surface shape

Science.gov (United States)

Gabovich, A. M.; Il'chenko, L. G.; Pashitskii, E. A.; Romanov, Yu. A.

1980-04-01

Using the Poisson equation Green function for a self-consistent field in a spatially inhomogeneous system, expressions for the electrostatic energy and screened charge interaction near the surface of a semi-infinite metal and a thin quantizing film are derived. It is shown that the decrease law and Friedel oscillation amplitude of adsorbed atom indirect interaction are determined by the electron spectrum character and the Fermi surface shape. The results obtained enable us to explain, in particular, the submonolayer adsorbed film structure on the W and Mo surfaces.

Nanometer emittance ultralow charge beams from rf photoinjectors

Directory of Open Access Journals (Sweden)

R. K. Li

2012-09-01

Full Text Available In this paper we discuss the generation of a new class of high brightness relativistic electron beams, characterized by ultralow charge (0.1–1 pC and ultralow normalized emittance (<50  nm. These beams are created in rf photoinjectors when the laser is focused on the cathode to very small transverse sizes (<30  μm rms. In this regime, the charge density at the cathode approaches the limit set by the extraction electric field. By shaping the laser pulse to have a cigarlike aspect ratio (the longitudinal dimension much larger than the transverse dimension and a parabolic temporal profile, the resulting space charge dominated dynamics creates a uniformly filled ellipsoidal distribution and the emittance can be nearly preserved to its thermal value. We also present a new method, based on a variation of the pepper-pot technique, for single shot measurements of the ultralow emittances for this new class of beams.

Performance of carbon fiber reinforced rubber composite armour against shaped charge jet penetration

Directory of Open Access Journals (Sweden)

Yue Lian-yong

2016-01-01

Full Text Available Natural rubber is reinforced with carbon fiber; the protective performances of the carbonfiber reinforced rubber composite armour to shaped charge jet have been studied based on the depth of penetration experiments. The craters on the witness blocks, the nature rubber based composite plates’ deformation and the Scanning Electron Microscopy for the hybrid fiber reinforced rubber plate also is analyzed. The results showed that the composite armour can affect the stability of the jet and made part of the jet fracture. The carbon fiber reinforced rubber composite armour has good defence ablity especially when the nature rubber plate hybrid 15% volume percentage carbonfiber and the obliquity angle is 68°. The hybrid fiber reinforced rubber composite armour can be used as a new kind of light protective armour.

A relativistic self-consistent model for studying enhancement of space charge limited emission due to counter-streaming ions

Science.gov (United States)

Lin, M. C.; Verboncoeur, J.

2016-10-01

A maximum electron current transmitted through a planar diode gap is limited by space charge of electrons dwelling across the gap region, the so called space charge limited (SCL) emission. By introducing a counter-streaming ion flow to neutralize the electron charge density, the SCL emission can be dramatically raised, so electron current transmission gets enhanced. In this work, we have developed a relativistic self-consistent model for studying the enhancement of maximum transmission by a counter-streaming ion current. The maximum enhancement is found when the ion effect is saturated, as shown analytically. The solutions in non-relativistic, intermediate, and ultra-relativistic regimes are obtained and verified with 1-D particle-in-cell simulations. This self-consistent model is general and can also serve as a comparison for verification of simulation codes, as well as extension to higher dimensions.

Experimental identification of a comb-shaped chaotic region in multiple parameter spaces simulated by the Hindmarsh—Rose neuron model

Science.gov (United States)

Jia, Bing

2014-03-01

A comb-shaped chaotic region has been simulated in multiple two-dimensional parameter spaces using the Hindmarsh—Rose (HR) neuron model in many recent studies, which can interpret almost all of the previously simulated bifurcation processes with chaos in neural firing patterns. In the present paper, a comb-shaped chaotic region in a two-dimensional parameter space was reproduced, which presented different processes of period-adding bifurcations with chaos with changing one parameter and fixed the other parameter at different levels. In the biological experiments, different period-adding bifurcation scenarios with chaos by decreasing the extra-cellular calcium concentration were observed from some neural pacemakers at different levels of extra-cellular 4-aminopyridine concentration and from other pacemakers at different levels of extra-cellular caesium concentration. By using the nonlinear time series analysis method, the deterministic dynamics of the experimental chaotic firings were investigated. The period-adding bifurcations with chaos observed in the experiments resembled those simulated in the comb-shaped chaotic region using the HR model. The experimental results show that period-adding bifurcations with chaos are preserved in different two-dimensional parameter spaces, which provides evidence of the existence of the comb-shaped chaotic region and a demonstration of the simulation results in different two-dimensional parameter spaces in the HR neuron model. The results also present relationships between different firing patterns in two-dimensional parameter spaces.

Experimental identification of a comb-shaped chaotic region in multiple parameter spaces simulated by the Hindmarsh—Rose neuron model

International Nuclear Information System (INIS)

Jia Bing

2014-01-01

A comb-shaped chaotic region has been simulated in multiple two-dimensional parameter spaces using the Hindmarsh—Rose (HR) neuron model in many recent studies, which can interpret almost all of the previously simulated bifurcation processes with chaos in neural firing patterns. In the present paper, a comb-shaped chaotic region in a two-dimensional parameter space was reproduced, which presented different processes of period-adding bifurcations with chaos with changing one parameter and fixed the other parameter at different levels. In the biological experiments, different period-adding bifurcation scenarios with chaos by decreasing the extra-cellular calcium concentration were observed from some neural pacemakers at different levels of extra-cellular 4-aminopyridine concentration and from other pacemakers at different levels of extra-cellular caesium concentration. By using the nonlinear time series analysis method, the deterministic dynamics of the experimental chaotic firings were investigated. The period-adding bifurcations with chaos observed in the experiments resembled those simulated in the comb-shaped chaotic region using the HR model. The experimental results show that period-adding bifurcations with chaos are preserved in different two-dimensional parameter spaces, which provides evidence of the existence of the comb-shaped chaotic region and a demonstration of the simulation results in different two-dimensional parameter spaces in the HR neuron model. The results also present relationships between different firing patterns in two-dimensional parameter spaces

Space charge effect measurements for a multi-channel ionization chamber used for synchrotron radiation

International Nuclear Information System (INIS)

Nasr, Amgad

2012-01-01

In vivo coronary angiography is one of the techniques used to investigate the heart diseases, by using catheter to inject a contrast medium of a given absorption coefficient into the heart vessels. Taking X-ray images produced by X-ray tube or synchrotron radiation for visualizing the blood in the coronary arteries. As the synchrotron radiation generated by the relativistic charged particle at the bending magnets, which emits high intensity photons in comparison with the X-ray tube. The intensity of the synchrotron radiation is varies with time. However for medical imaging it's necessary to measure the incoming intensity with the integrated time. The thesis work includes building a Multi-channel ionization chamber which can be filled with noble gases N 2 , Ar and Xe with controlled inner pressure up to 30 bar. This affects the better absorption efficiency in measuring the high intensity synchrotron beam fluctuation. The detector is a part of the experimental setup used in the k-edge digital subtraction angiography project, which will be used for correcting the angiography images taken by another detector at the same time. The Multi-channel ionization chamber calibration characteristics are measured using 2 kW X-ray tube with molybdenum anode with characteristic energy of 17.44 keV. According to the fast drift velocity of the electrons relative to the positive ions, the electrons will be collected faster at the anode and will induce current signals, while the positive ions is still drifting towards the cathode. However the accumulation of the slow ions inside the detector disturbs the homogeneous applied electric field and leads to what is known a space charge effect. In this work the space charge effect is measured with very high synchrotron photons intensity from EDR beam line at BESSYII. The strong attenuation in the measured amplitude signal occurs when operating the chamber in the recombination region. A plateau is observed at the amplitude signal when

Correlating shaped charge performance with processing conditions and microstructure of an aluminum alloy 1100 liner enabled by a new method to arrest nascent jet formation

Science.gov (United States)

Scheid, James Eric

Aluminum-lined shaped charges are used in special applications where jet and / or slug residue in the target is undesired. The three different microstructures of the aluminum liners studied herein resulted from three different manufacturing interpretations of the same design. One interpretation was completely machining the liners from best available annealed round stock. The second was to cold-forge the liners from annealed round-stock in an open-die forge to near-final dimensions, and then machine the liners to the final dimensions. The third variant in this study was to use the above forged liner, but with annealing after the machining. These three manufacturing choices resulted in significant variations in shaped charge performance. The goal of this research was to clarify the relationships between the liner metal microstructure and properties, and the corresponding shaped charge dynamic flow behavior. What began as an investigation into user-reported performance problems associated inherently with liner manufacturing processes and resultant microstructure, resolved into new understandings of the relationships between aluminum liner microstructure and shaped charge collapse kinetics. This understanding was achieved through an extensive literature review and the comprehensive characterization of the material properties of three variants of an 1100 aluminum shaped charge liner with a focus on collapse and nascent jet formation. The machined liner had a microstructure with large millimeter-sized grains and fine particles aligned in bands parallel to the charge axis. The forged liner microstructure consisted of very small one micrometer-sized (1 mum) subgrains and fine particles aligned largely in bands elongated parallel to the liner contour. The annealed liner was characterized by ten micrometer (10 mum) sized equiaxed grains with residual fine particles in the forged alignment. This characterization was enabled by the development, execution and validation of a

Emittance growth due to space charge compensation and beam intensity instabilities in negative ion beams

Directory of Open Access Journals (Sweden)

C. A. Valerio-Lizarraga

2018-03-01

Full Text Available The need to extract the maximum beam intensity with low transversal emittance often comes with the drawback of operating the ion source to limits where beam current instabilities arise, such fluctuations can change the beam properties producing a mismatch in the following sections of the machine. The space charge compensation (SCC generated by the beam particles colliding with the residual gas reaches a steady state after a build-up time. This paper shows how once in the steady state, the beam ends with a transversal emittance value bigger than the case without compensation. In addition, we study how the beam intensity variation can disturb the SCC dynamics and its impact on the beam properties. The results presented in this work come from 3-D simulations using tracking codes taking into account the secondary ions to estimate the degree of the emittance growth due to space charge and SCC.

Simulation of space-charge effects in an ungated GEM-based TPC

Energy Technology Data Exchange (ETDEWEB)

Böhmer, F.V., E-mail: felix.boehmer@tum.de; Ball, M.; Dørheim, S.; Höppner, C.; Ketzer, B.; Konorov, I.; Neubert, S.; Paul, S.; Rauch, J.; Vandenbroucke, M.

2013-08-11

A fundamental limit to the application of Time Projection Chambers (TPCs) in high-rate experiments is the accumulation of slowly drifting ions in the active gas volume, which compromises the homogeneity of the drift field and hence the detector resolution. Conventionally, this problem is overcome by the use of ion-gating structures. This method, however, introduces large dead times and restricts trigger rates to a few hundred per second. The ion gate can be eliminated from the setup by the use of Gas Electron Multiplier (GEM) foils for gas amplification, which intrinsically suppress the backflow of ions. This makes the continuous operation of a TPC at high rates feasible. In this work, Monte Carlo simulations of the buildup of ion space charge in a GEM-based TPC and the correction of the resulting drift distortions are discussed, based on realistic numbers for the ion backflow in a triple-GEM amplification stack. A TPC in the future P{sup ¯}ANDA experiment at FAIR serves as an example for the experimental environment. The simulations show that space charge densities up to 65 fC cm{sup −3} are reached, leading to electron drift distortions of up to 10 mm. The application of a laser calibration system to correct these distortions is investigated. Based on full simulations of the detector physics and response, we show that it is possible to correct for the drift distortions and to maintain the good momentum resolution of the GEM-TPC.

Simulation of space-charge effects in an ungated GEM-based TPC

International Nuclear Information System (INIS)

Böhmer, F.V.; Ball, M.; Dørheim, S.; Höppner, C.; Ketzer, B.; Konorov, I.; Neubert, S.; Paul, S.; Rauch, J.; Vandenbroucke, M.

2013-01-01

A fundamental limit to the application of Time Projection Chambers (TPCs) in high-rate experiments is the accumulation of slowly drifting ions in the active gas volume, which compromises the homogeneity of the drift field and hence the detector resolution. Conventionally, this problem is overcome by the use of ion-gating structures. This method, however, introduces large dead times and restricts trigger rates to a few hundred per second. The ion gate can be eliminated from the setup by the use of Gas Electron Multiplier (GEM) foils for gas amplification, which intrinsically suppress the backflow of ions. This makes the continuous operation of a TPC at high rates feasible. In this work, Monte Carlo simulations of the buildup of ion space charge in a GEM-based TPC and the correction of the resulting drift distortions are discussed, based on realistic numbers for the ion backflow in a triple-GEM amplification stack. A TPC in the future P ¯ ANDA experiment at FAIR serves as an example for the experimental environment. The simulations show that space charge densities up to 65 fC cm −3 are reached, leading to electron drift distortions of up to 10 mm. The application of a laser calibration system to correct these distortions is investigated. Based on full simulations of the detector physics and response, we show that it is possible to correct for the drift distortions and to maintain the good momentum resolution of the GEM-TPC

q-deformed charged fermion coherent states and SU(3) charged, Hyper-charged fermion coherent states

International Nuclear Information System (INIS)

Hao Sanru; Li Guanghua; Long Junyan

1994-01-01

By virtue of the algebra of the q-deformed fermion oscillators, the q-deformed charged fermion coherent states and SU(3) charged, hyper-charged fermion coherent states are discussed. The explicit forms of the two kinds of coherent states mentioned above are obtained by making use of the completeness of base vectors in the q-fermion Fock space. By comparing the q-deformed results with the ordinary results, it is found that the q-deformed charged fermion coherent states and SU(3) charged, hyper-charged fermion coherent states are automatically reduced to the ordinary charged fermion coherent states and SU(3) charged hyper-charged fermion coherent states if the deformed parameter q→1

The Influence of Pre-conditioning on the Space Charge Formation in LDPE and XLPE

DEFF Research Database (Denmark)

Henriksen, Mogens; Holbøll, Joachim T.; Fleming, R.J.

1996-01-01

Planar LDPE and XLPE samples were conditioned by holding in short circuit for 48 hrs. at 40oC under rotary pump pressure, and space charge accumulation in these samples under DC fields of 20 kV/mm was then compared with the corresponding accumulation in unconditioned samples.The test results were...

Increased-accuracy numerical modeling of electron-optical systems with space-charge

International Nuclear Information System (INIS)

Sveshnikov, V.

2011-01-01

This paper presents a method for improving the accuracy of space-charge computation for electron-optical systems. The method proposes to divide the computational region into two parts: a near-cathode region in which analytical solutions are used and a basic one in which numerical methods compute the field distribution and trace electron ray paths. A numerical method is used for calculating the potential along the interface, which involves solving a non-linear equation. Preliminary results illustrating the improvement of accuracy and the convergence of the method for a simple test example are presented.

A relativistic self-consistent model for studying enhancement of space charge limited field emission due to counter-streaming ions

International Nuclear Information System (INIS)

Lin, M. C.; Lu, P. S.; Chang, P. C.; Ragan-Kelley, B.; Verboncoeur, J. P.

2014-01-01

Recently, field emission has attracted increasing attention despite the practical limitation that field emitters operate below the Child-Langmuir space charge limit. By introducing counter-streaming ion flow to neutralize the electron charge density, the space charge limited field emission (SCLFE) current can be dramatically enhanced. In this work, we have developed a relativistic self-consistent model for studying the enhancement of SCLFE by a counter-streaming ion current. The maximum enhancement is found when the ion effect is saturated, as shown analytically. The solutions in non-relativistic, intermediate, and ultra-relativistic regimes are obtained and verified with 1-D particle-in-cell simulations. This self-consistent model is general and can also serve as a benchmark or comparison for verification of simulation codes, as well as extension to higher dimensions

Space charge effect in SQS transition in a gas counter

International Nuclear Information System (INIS)

Ohgaki, Hideaki; Kametani, Hitoshi; Fujita, Yasuyuki; Uozumi, Yuusuke; Ijiri, Hidenobu; Matoba, Masaru; Sakae, Takeji; Koori, Norihiko

1990-01-01

Systematic investigation of the gas multiplication characteristics in the transition region from proportional to SQS mode in a cylindrical proportional counter has been performed. The property of saturation of the gas multiplication factor can be reproduced using the effective electric field which is corrected for the space charge related to the positive ion density in the avalanche. Photon-mediated gas multiplication can explain the large jump phenomenon of the SQS transition. It is shown that the effective electric field in the avalanche becomes almost zero near the anode surface (Meek's streamer condition) at the 50% transition voltage and the region of its maximum moves slightly away from the anode surface. (orig.)

High-energy charged particle bursts in the near-Earth space as earthquake precursors

Directory of Open Access Journals (Sweden)

S. Yu. Aleksandrin

2003-02-01

Full Text Available The experimental data on high-energy charged particle fluxes, obtained in various near-Earth space experiments (MIR orbital station, METEOR-3, GAMMA and SAMPEX satellites were processed and analyzed with the goal to search for particle bursts. Particle bursts have been selected in every experiment considered. It was shown that the significant part of high-energy charged particle bursts correlates with seismic activity. Moreover, the particle bursts are observed several hours before strong earthquakes; L-shells of particle bursts and corresponding earthquakes are practically the same. Some features of a seismo-magnetosphere connection model, based on the interaction of electromagnetic emission of seismic origin and radiation belt particles, were considered. Key words. Ionospheric physics (energetic particles, trapped; energetic particles, precipitating; magnetosphere-ionosphere interactions

Transport properties of triarylamine based dendrimers studied by space charge limited current transients

Science.gov (United States)

Szymanski, Marek Z.; Kulszewicz-Bajer, Irena; Faure-Vincent, Jérôme; Djurado, David

2012-08-01

We have studied hole transport in triarylamine based dendrimer using space-charge-limited current transient technique. A mobility of 8 × 10-6 cm2/(V s) and a characteristic detrapping time of about 100 ms have been obtained. We found that quasi-ohmic contact is formed with gold. The obtained mobility differs from the apparent one given by the analysis of stationary current-voltage characteristics because of a limited contact efficiency. The comparison between transients obtained from fresh and aged samples reveals no change in mobility with aging. The deterioration of electrical properties is exclusively caused by trap formation and accumulation of ionic conducting impurities. Finally, repeated transient measurements have been applied to analyze the dynamics of charge trapping process.

Space Charge Saturated Sheath Regime and Electron Temperature Saturation in Hall Thrusters

International Nuclear Information System (INIS)

Raitses, Y.; Staack, D.; Smirnov, A.; Fisch, N.J.

2005-01-01

Secondary electron emission in Hall thrusters is predicted to lead to space charge saturated wall sheaths resulting in enhanced power losses in the thruster channel. Analysis of experimentally obtained electron-wall collision frequency suggests that the electron temperature saturation, which occurs at high discharge voltages, appears to be caused by a decrease of the Joule heating rather than by the enhancement of the electron energy loss at the walls due to a strong secondary electron emission

Postglomerular capillary solute flux restricted by shape and charge in the dog

International Nuclear Information System (INIS)

Whiteside, C.; Silverman, M.

1987-01-01

The permselectivity characteristics of the postglomerular (PG) microcirculation in dog kidney were investigated employing 3 H-labeled cationic (DEAE) and anionic sulfated dextrans (dextran-SO 4 ) ranging from 19 to 29 angstrom Stokes-Einstein Radius. With the use of the multiple-indicator dilution (MID) technique, a bolus injection was made into the left renal artery and timed serial samples were obtained from renal venous and urine outflows. The injection solution contained 125 I-labeled albumin (plasma reference), [ 14 C]inulin and/or creatinine (glomerular and interstitial references), and a test [ 3 H]dextran probe. A control run was carried out with tracer, then charge interaction was analyzed by repeating the MID run with excess unlabeled compound or after protamine sulfate infusion. After loading, renal vein recovery and mean transit time (bar t) were unchanged relative to [ 14 C]inulin for [ 3 H]dextran-SO 4 . But excess DEAE resulted in reduced recovery and decreased bar t for [ 3 H]DEAE. After protamine sulfate, the renal vein and urine recoveries of [ 3 H]dextran-SO 4 decreased and the renal vein bar t increased. These findings demonstrate saturable anionic binding sites in the PG microcirculation. Under conditions where charge interaction was eliminated, the ratio of renal vein bar t for 125 I-albumin to cationic or anionic dextran was always less than its ratio to neutral dextran, implying a larger apparent volume of distribution. The authors concluded that PG capillaries also limit solute flux on the basis of shape

Calculation and measurement of space charge in MV-size xxtruded cables systems under load conditions

NARCIS (Netherlands)

Morshuis, P.H.F.; Bodega, R.; Fabiani, D.; Montanari, G.C.; Dissado, L.A.; Smit, J.J.

2007-01-01

A load current in dc high voltage cables results in a temperature drop across the insulation and hence a radial distribution of the insulation conductivity is found. Direct consequence is an accumulation of space charge in the bulk of the nsulation, that may significantly affect its reliability.

Sustainable Shaping of Urban Spaces in the Context of the Environment

Directory of Open Access Journals (Sweden)

Joanna Agnieszka Pawłowicz

2017-11-01

Full Text Available The natural environment is of great importance when it comes to developing a city, as it shapes its spaces, defines its roles and performs climatic and protective functions. Industrialization often requires removing landscape obstacles and vegetation to erect new buildings. An urban planner, though, should be aware of the borders that must not be crossed. Designing new streets and buildings should follow a sustainable growth pattern, if the city landscape and its climatic conditions are to improve for generations to come. This paper discusses the aspects of planning and managing urban spaces in such a way as to provide their users with healthy and comfortable living conditions. The paper is based on a survey conducted to gather the opinions of members of a city community on the environment in which they live.

Quadrupole beam-transport experiment for heavy ions under extreme space charge conditions

International Nuclear Information System (INIS)

Chupp, W.; Faltens, A.; Hartwig, E.C.

1983-03-01

A Cs ion-beam-transport experiment is in progress to study beam behavior under extreme space-charge conditions. A five-lens section matches the beam into a periodic electrostatic quadrupole FODO channel and its behavior is found to agree with predictions. With the available parameters (less than or equal to 200 keV, less than or equal to 20 mA, πepsilon/sub n/ greater than or equal to 10 - 7 π rad-m, up to 41 periods) the transverse (betatron) occillation frequency (nu) can be depressed down to one-tenth of its zero current value (nu/sub 0/), where nu/sup 2/ = nu/sub 0//sup 2/ -#betta#/sub p/ 2 /2, and #betta#/sub p/ is the beam plasma frequency. The current can be controlled by adjustment of the gun and the emittance can be controlled independently by means of a set of charged grids

A Gauss-Newton method for the integration of spatial normal fields in shape Space

KAUST Repository

Balzer, Jonathan

2011-08-09

We address the task of adjusting a surface to a vector field of desired surface normals in space. The described method is entirely geometric in the sense, that it does not depend on a particular parametrization of the surface in question. It amounts to solving a nonlinear least-squares problem in shape space. Previously, the corresponding minimization has been performed by gradient descent, which suffers from slow convergence and susceptibility to local minima. Newton-type methods, although significantly more robust and efficient, have not been attempted as they require second-order Hadamard differentials. These are difficult to compute for the problem of interest and in general fail to be positive-definite symmetric. We propose a novel approximation of the shape Hessian, which is not only rigorously justified but also leads to excellent numerical performance of the actual optimization. Moreover, a remarkable connection to Sobolev flows is exposed. Three other established algorithms from image and geometry processing turn out to be special cases of ours. Our numerical implementation founds on a fast finite-elements formulation on the minimizing sequence of triangulated shapes. A series of examples from a wide range of different applications is discussed to underline flexibility and efficiency of the approach. © 2011 Springer Science+Business Media, LLC.

On a possibility of creation of positive space charge cloud in a system with magnetic insulation of electrons

International Nuclear Information System (INIS)

Goncharov, A.A.; Dobrovol'skii, A.M.; Dunets, S.P.; Evsyukov, A.N.; Protsenko, I.M.

2009-01-01

We describe a new approach for creation an effective, low-cost, low-maintenance axially symmetric plasma optical tools for focusing and manipulating high-current beams of negatively charged particles, electrons and negative ions. This approach is based on fundamental plasma optical concept of magnetic insulation of electrons and non-magnetized positive ions providing creation of controlled uncompensated cloud of the space charge. The axially symmetric electrostatic plasma optical lens is well-known and well developed tool where this concept is used successfully. This provides control and focusing high-current positive ion beams in wide range of parameters. Here for the first time we present optimistic experimental results describing the application of an idea of magnetic insulation of electrons for generation of the stable cloud of positive space charge by focusing onto axis the converging stream of heavy ions produced by circular accelerator with closed electron drift. The estimations of a maximal concentration of uncompensated cloud of positive ions are also made

Shape control of slack space reflectors using modulated solar pressure.

Science.gov (United States)

Borggräfe, Andreas; Heiligers, Jeannette; Ceriotti, Matteo; McInnes, Colin R

2015-07-08

The static deflection profile of a large spin-stabilized space reflector because of solar radiation pressure acting on its surface is investigated. Such a spacecraft consists of a thin reflective circular film, which is deployed from a supporting hoop structure in an untensioned, slack manner. This paper investigates the use of a variable reflectivity distribution across the surface to control the solar pressure force and hence the deflected shape. In this first analysis, the film material is modelled as one-dimensional slack radial strings with no resistance to bending or transverse shear, which enables a semi-analytic derivation of the nominal deflection profile. An inverse method is then used to find the reflectivity distribution that generates a specific, for example, parabolic deflection shape of the strings. Applying these results to a parabolic reflector, short focal distances can be obtained when large slack lengths of the film are employed. The development of such optically controlled reflector films enables future key mission applications such as solar power collection, radio-frequency antennae and optical telescopes.

Space charge effect measurements for a multi-channel ionization chamber used for synchrotron radiation

Energy Technology Data Exchange (ETDEWEB)

Nasr, Amgad

2012-07-18

In vivo coronary angiography is one of the techniques used to investigate the heart diseases, by using catheter to inject a contrast medium of a given absorption coefficient into the heart vessels. Taking X-ray images produced by X-ray tube or synchrotron radiation for visualizing the blood in the coronary arteries. As the synchrotron radiation generated by the relativistic charged particle at the bending magnets, which emits high intensity photons in comparison with the X-ray tube. The intensity of the synchrotron radiation is varies with time. However for medical imaging it's necessary to measure the incoming intensity with the integrated time. The thesis work includes building a Multi-channel ionization chamber which can be filled with noble gases N{sub 2}, Ar and Xe with controlled inner pressure up to 30 bar. This affects the better absorption efficiency in measuring the high intensity synchrotron beam fluctuation. The detector is a part of the experimental setup used in the k-edge digital subtraction angiography project, which will be used for correcting the angiography images taken by another detector at the same time. The Multi-channel ionization chamber calibration characteristics are measured using 2 kW X-ray tube with molybdenum anode with characteristic energy of 17.44 keV. According to the fast drift velocity of the electrons relative to the positive ions, the electrons will be collected faster at the anode and will induce current signals, while the positive ions is still drifting towards the cathode. However the accumulation of the slow ions inside the detector disturbs the homogeneous applied electric field and leads to what is known a space charge effect. In this work the space charge effect is measured with very high synchrotron photons intensity from EDR beam line at BESSYII. The strong attenuation in the measured amplitude signal occurs when operating the chamber in the recombination region. A plateau is observed at the amplitude signal when

Controlling nonlinear longitudinal space charge oscillations for high peak current bunch train generation

Directory of Open Access Journals (Sweden)

P. Musumeci

2013-10-01

Full Text Available The evolution of picosecond modulations of the longitudinal profile of an electron beam generated in an rf photoinjector is analyzed and optimized with the goal of obtaining high peak current electron bunch trains at very high frequencies (≥THz. Taking advantage of nonlinear longitudinal space charge forces, it is found that more than 500 A peak current 1 THz bunch trains can be generated using a standard 1.6 cell SLAC/UCLA/BNL rf gun. Postacceleration is used to freeze the longitudinal phase space dynamics after one half plasma oscillation. Applications range from tunable narrow bandwidth THz radiation generation to drivers for high frequency high gradient accelerators.

Space-charge limits on the transport of ion beams in a long alternating gradient system

International Nuclear Information System (INIS)

Tiefenback, M.G.

1986-11-01

We have experimentally studied the space-charge-dominated transport of ion beams in an alternating-gradient channel, without acceleration. We parameterize the focusing strength in terms of the zero-current ''betatron'' oscillation phase advance rate, σ 0 (degrees per focusing period). We have investigated the conditions for ''stability'', defined as the constancy of the total current and phase space area of the beam during transport. We find that the beam may be transported with neither loss of current nor growth in phase area if σ 0 0 . In this regime, the space-charge repulsive force can counter 98-99% of the externally applied focusing field, and the oscillation frequency of the beam particles can be depressed by self-forces to almost a factor of 10 below the zero-current value, limited only by the optical quality of our ion source. For σ 0 > 90 0 , we find that collective interactions bound the maintainable density of the beam, and we present a simple, semi-empirical characterization for stability, within our ability to distinguish the growth rate from zero in our apparatus. Our channel comprises 87 quadrupole lenses, 5 of which are used to prepare the beam for injection into the non-azimuthally-symmetric focusing channel

Using emergent order to shape a space society

Science.gov (United States)

Graps, Amara L.

1993-01-01

A fast-growing movement in the scientific community is reshaping the way that we view the world around us. The short-hand name for this movement is 'chaos'. Chaos is a science of the global, nonlinear nature of systems. The center of this set of ideas is that simple, deterministic systems can breed complexity. Systems as complex as the human body, ecology, the mind or a human society. While it is true that simple laws can breed complexity, the other side is that complex systems can breed order. It is the latter that I will focus on in this paper. In the past, nonlinear was nearly synonymous with unsolvable because no general analytic solutions exist. Mathematically, an essential difference exists between linear and nonlinear systems. For linear systems, you just break up the complicated system into many simple pieces and patch together the separated solutions for each piece to form a solution to the full problem. In contrast, solutions to a nonlinear system cannot be added to form a new solution. The system must be treated in its full complexity. While it is true that no general analytical approach exists for reducing a complex system such as a society, it can be modeled. The technical involves a mathematical construct called phase space. In this space stable structures can appear which I use as analogies for the stable structures that appear in a complex system such as an ecology, the mind or a society. The common denominator in all of these systems is that they rely on a process called feedback loops. Feedback loops link the microscopic (individual) parts to the macroscopic (global) parts. The key, then, in shaping a space society, is in effectively using feedback loops. This paper will illustrate how one can model a space society by using methods that chaoticists have developed over the last hundred years. And I will show that common threads exist in the modeling of biological, economical, philosophical, and sociological systems.

Water Tree Influence on Space Charge Distribution and on the Residual Electric Field in Polyethylene Insulation

Directory of Open Access Journals (Sweden)

Cristina Stancu

2009-10-01

Full Text Available A computation method of the electricfield and ionic space charge density in planeinsulations with water trees (using a ComsolMultiphysics software and the thermal step currents(Im(t measured with Thermal Step Method ispresented. A parabolic spatial variation of volumecharge density, an exponential spatial variation ofthe electric permittivity ε and a linear dependency ofε and the temperature coefficient of permittivity αεwith the average water concentration in trees, areconsidered. For a water tree with a known length,different values of charge density are consideredand the electric field and the thermal step currentsIc(t are calculated. The currents Ic(t and Im(t arecompared and the volume of charge density andelectric field for which Ic(t is identical with Im(t arekept.