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Sample records for cornell electron-positron storage ring

  1. Observation of Electron Cloud Instabilities and Emittance Dilution at the Cornell Electron-Positron Storage Ring Test Accelerator

    Science.gov (United States)

    Holtzapple, R. L.; Billing, M. G.; Campbell, R. C.; Dugan, G. F.; Flanagan, J.; McArdle, K. E.; Miller, M. I.; Palmer, M. A.; Ramirez, G. A.; Sonnad, K. G.; Totten, M. M.; Tucker, S. L.; Williams, H. A.

    2016-04-01

    Electron cloud related emittance dilution and instabilities of bunch trains limit the performance of high intensity circular colliders. One of the key goals of the Cornell electron-positron storage ring Test Accelerator (CesrTA) research program is to improve our understanding of how the electron cloud alters the dynamics of bunches within the train. Single bunch beam diagnotics have been developed to measure the beam spectra, vertical beam size, two important dynamical effects of beams interacting with the electron cloud, for bunch trains on a turn-by-turn basis. Experiments have been performed at CesrTA to probe the interaction of the electron cloud with stored positron bunch trains. The purpose of these experiments was to characterize the dependence of beam-electron cloud interactions on the machine parameters such as bunch spacing, vertical chromaticity, and bunch current. The beam dynamics of the stored beam, in the presence of the electron cloud, was quantified using: 1) a gated beam position monitor (BPM) and spectrum analyzer to measure the bunch-by-bunch frequency spectrum of the bunch trains; 2) an x-ray beam size monitor to record the bunch-by-bunch, turn-by-turn vertical size of each bunch within the trains. In this paper we report on the observations from these experiments and analyze the effects of the electron cloud on the stability of bunches in a train under many different operational conditions.

  2. Design Considerations for High Energy Electron -- Positron Storage Rings

    Science.gov (United States)

    Richter, B.

    1966-11-01

    High energy electron-positron storage rings give a way of making a new attack on the most important problems of elementary particle physics. All of us who have worked in the storage ring field designing, building, or using storage rings know this. The importance of that part of storage ring work concerning tests of quantum electrodynamics and mu meson physics is also generally appreciated by the larger physics community. However, I do not think that most of the physicists working tin the elementary particle physics field realize the importance of the contribution that storage ring experiments can make to our understanding of the strongly interacting particles. I would therefore like to spend the next few minutes discussing the sort of things that one can do with storage rings in the strongly interacting particle field.

  3. Low-emittance tuning at the Cornell Electron Storage Ring

    CERN Document Server

    Shanks, James; Sagan, David

    2013-01-01

    In 2008 the Cornell Electron/Positron Storage Ring (CESR) was reconfigured from an electron/positron collider to serve as a testbed for the International Linear Collider (ILC) damping rings. One of the primary goals of the CESR Test Accelerator (CesrTA) project is to develop low emittance tuning techniques to achieve sub-10pm geometric vertical emittance at 2.085 GeV. This paper discusses the tuning methods used at CesrTA to achieve low-emittance conditions. A minimum vertical emittance of 8.7 +2.9/-3.4(sys) +/-0.2(stat) pm has been achieved at 2.085 GeV. In various configurations and beam energies the correction technique routinely achieves vertical emittance <15 pm after correction. Beam-based measurement and correction requires about 15 minutes. Simulations modeling the effects of magnet misalignments, BPM errors, and emittance correction algorithm suggest the residual vertical emittance measured at the conclusion of the tuning procedure is dominated by sources other than optics errors and misalignments...

  4. A Monte-Carlo simulation of the equilibrium beam polarization in ultra-high energy electron(positron) storage rings

    CERN Document Server

    Duan, Zhe; Barber, Desmond P; Qin, Qing

    2015-01-01

    With the recently emerging global interest in building a next generation of circular electron-positron colliders to study the properties of the Higgs boson, and other important topics in particle physics at ultra-high beam energies, it is also important to pursue the possibility of implementing polarized beams at this energy scale. It is therefore necessary to set up simulation tools to evaluate the beam polarization at these ultra-high beam energies. In this paper, a Monte-Carlo simulation of the equilibrium beam polarization based on the Polymorphic Tracking Code(PTC) is described. The simulations are for a model storage ring with parameters similar to those of proposed circular colliders in this energy range, and they are compared with the suggestion that there are different regimes for the spin dynamics underlying the polarization of a beam in the presence of synchrotron radiation at ultra-high beam energies. In particular, it has been suggested that the so-called "correlated" crossing of spin resonances ...

  5. Measurement and Compensation of Horizontal Crabbing at the Cornell Electron Storage Ring Test Accelerator

    CERN Document Server

    Ehrlichman, M P; Hartung, W; Peterson, D P; Rider, N; Rubin, D; Sagan, D; Shanks, J P; Wang, S T

    2013-01-01

    In storage rings, horizontal dispersion in the rf cavities introduces horizontal-longitudinal ($xz$) coupling, contributing to beam tilt in the $xz$ plane. This coupling can be characterized by a "crabbing" dispersion term $\\zeta_a$ that comes from decomposing the $1$-turn transfer matrix. $\\zeta_a$ is proportional to the rf cavity voltage and the horizontal dispersion in the cavity. We report experiments at the Cornell Electron Storage Ring Test Accelerator (CesrTA) where $xz$ coupling was explored using three lattices with distinct crabbing properties. We characterize the $xz$ coupling for each case by measuring the horizontal projection of the beam with a beam size monitor. The three lattice configurations correspond to a) $16$ mrad $xz$ tilt at the beam size monitor source point, b) compensation of the $\\zeta_a$ introduced by one of two pairs of RF cavities with the second, and c) zero dispersion in RF cavities, eliminating $\\zeta_a$ entirely. Additionally, intrabeam scattering (IBS) is evident in our mea...

  6. Characterization of electron clouds in the Cornell Electron Storage Ring Test Accelerator using TE-wave transmission

    Energy Technology Data Exchange (ETDEWEB)

    De Santis, S.; Byrd, J. M.; Billing, M.; Palmer, M.; Sikora, J.; Carlson, B.

    2010-01-02

    A relatively new technique for measuring the electron cloud density in storage rings has been developed and successfully demonstrated [S. De Santis, J.M. Byrd, F. Caspers, A. Krasnykh, T. Kroyer, M.T.F. Pivi, and K.G. Sonnad, Phys. Rev. Lett. 100, 094801 (2008).]. We present the experimental results of a systematic application of this technique at the Cornell Electron Storage Ring Test Accelerator. The technique is based on the phase modulation of the TE mode transmitted in a synchrotron beam pipe caused by the periodic variation of the density of electron plasma. Because of the relatively simple hardware requirements, this method has become increasingly popular and has been since successfully implemented in several machines. While the principles of this technique are straightforward, quantitative derivation of the electron cloud density from the measurement requires consideration of several effects, which we address in detail.

  7. The Conversion and operation of the Cornell electron storage ring as a test accelerator (cesrta) for damping rings research and development

    Energy Technology Data Exchange (ETDEWEB)

    Palmer, M.A.; Alexander, J.; Byrd, J.; Celata, C.M.; Corlett, J.; De Santis, S.; Furman, M.; Jackson, A.; Kraft, R.; Munson, D.; Penn, G.; Plate, D.; Rawlins, A.; Venturini, M.; Zisman, M.; Billing, M.; Calvey, J.; Chapman, S.; Codner, G.; Conolly, C.; Crittenden, J.; Dobbins, J.; Dugan, G.; Fontes, E.; Forster, M.; Gallagher, R.; Gray, S.; Greenwald, S.; Hartill, D.; Hopkins, W.; Kandaswamy, J.; Kreinick, D.; Li, Y.; Liu, X.; Livezey, J.; Lyndaker, A.; Medjidzade, V.; Meller, R.; Peck, S.; Peterson, D.; Rendina, M.; Revesz, P.; Rice, D.; Rider, N.; Rubin, D.; Sagan, D.; Savino, J.; Seeley, R.; Sexton, J.; Shanks, J.; Sikora, J.; Smolenski, K.; Strohman, C.; Temnykh, A.; tigner, M.; Whitney, W.; Williams, H.; Vishniakou, S.; Wilkens, T.; Harkay, K.; Holtzapple, R.; Smith, E.; Jones, J.; Wolski, A.; He, Y.; Ross, M.; Tan, C.Y.; Zwaska, R.; Flanagan, J.; Jain, P.; Kanazawa, K.; Ohmi, K.; Sakai, H.; Shibata, K.; Suetsugu, Y.; Kharakh, D.; Pivi, M.; Wang, L.

    2009-05-01

    In March of 2008, the Cornell Electron Storage Ring (CESR) concluded twenty eight years of colliding beam operations for the CLEO high energy physics experiment. We have reconfigured CESR as an ultra low emittance damping ring for use as a test accelerator (CesrTA) for International Linear Collider (ILC) damping ring R&D. The primary goals of the CesrTA program are to achieve a beam emittance approaching that of the ILC Damping Rings with a positron beam, to investigate the interaction of the electron cloud with both low emittance positron and electron beams, to explore methods to suppress the electron cloud, and to develop suitable advanced instrumentation required for these experimental studies (in particular a fast x-ray beam size monitor capable of single pass measurements of individual bunches). We report on progress with the CESR conversion activities, the status and schedule for the experimental program, and the first experimental results that have been obtained.

  8. Bruno Touschek: From Betatrons to Electron-Positron Colliders

    Science.gov (United States)

    Bernardini, Carlo; Pancheri, Giulia; Pellegrini, Claudio

    Bruno Touschek’s life as a physicist spanned the period from World War II to the 1970s. He was a key figure in the developments of electron-positron colliders and storage rings, and made important contributions to theoretical high energy physics. Storage rings, initially developed for high energy physics, are being widely used in many countries as synchrotron radiation sources and are a tool for research in physics, chemistry, biology, environmental sciences and cultural heritage studies. We describe Touschek’s life in Austria, where he was born, in Germany, where he participated in the construction of a betatron during WWII, and in Italy, where he proposed and led to completion the first electron-positron storage ring in 1960, in Frascati. We highlight how his central European culture influenced his lifestyle and work, and his main contributions to physics, such as the discovery of the Touschek effect and beam instabilities in the larger storage ring ADONE.

  9. Bruno Touschek, from Betatrons to Electron-positron Colliders

    CERN Document Server

    Bernardini, Carlo; Pellegrini, Claudio

    2015-01-01

    Bruno Touschek's life as a physicist spanned the period from World War II to the 1970s. He was a key figure in the developments of electron-positron colliders, storage rings, and gave important contributions to theoretical high energy physics. Storage rings, initially developed for high energy physics, are being widely used in many countries as synchrotron radiation sources and are a tool for research in physics, chemistry, biology environmental sciences and cultural heritage studies. We describe Touschek's life in Austria, where he was born, Germany, where he participated to the construction of a betatron during WWII, and Italy, where he proposed and led to completion the first electron-positron storage ring in 1960, in Frascati. We highlight how his central European culture influenced his life style and work, and his main contributions to physics, such as the discovery of the Touschek effect and beam instabilities in the larger storage ring ADONE.

  10. Search for bound-state electron+positron pair decay

    Science.gov (United States)

    Bosch, F.; Hagmann, S.; Hillenbrand, P.-M.; Lane, G. J.; Litvinov, Yu. A.; Reed, M. W.; Sanjari, M. S.; Stöhlker, Th.; Torilov, S. Yu.; Tu, X. L.; Walke, P. M.

    2016-09-01

    The heavy ion storage rings coupled to in-flight radioactive-ion beam facilities, namely the ability to produce and store for extended periods of time radioactive nuclides in high atomic charge states, for the searchof yet unobserved decay mode - bound-state electron-positron pair decay.

  11. Critical remarks on the electron (positron) beam polarization by Compton scattering on circular polarized laser photons

    CERN Document Server

    Kotkin, G L; Telnov, V I

    2003-01-01

    In a number of papers an attractive method of laser polarization of electrons (positrons) at storage rings or linear colliders have been proposed. We show that these suggestions are incorrect and based on errors in simulation of multiple Compton scattering and in calculation of the Compton spin-flip cross sections. We argue that the equilibrium polarization in this method is zero.

  12. Heavy ion storage rings

    Energy Technology Data Exchange (ETDEWEB)

    Schuch, R.

    1987-01-01

    A brief overview of synchrotron storage rings for heavy ions, which are presently under construction in different accelerator laboratories is given. Ions ranging from protons up to uranium ions at MeV/nucleon energies will be injected into these rings using multiturn injection from the accelerators available or being built in these laboratories. After injection, it is planned to cool the phase space distribution of the ions by merging them with cold electron beams or laser beams, or by using stochastic cooling. Some atomic physics experiments planned for these rings are presented.

  13. Autumn study on storage rings

    CERN Multimedia

    1974-01-01

    The first two weeks of October have seen storage ring people from accelerator Laboratories throughout the world at CERN to study the fundamental problems of very high energy protonproton colliding beam machines.

  14. A new storage-ring light source

    Energy Technology Data Exchange (ETDEWEB)

    Chao, Alex [SLAC National Accelerator Lab., Menlo Park, CA (United States)

    2015-06-01

    A recently proposed technique in storage ring accelerators is applied to provide potential high-power sources of photon radiation. The technique is based on the steady-state microbunching (SSMB) mechanism. As examples of this application, one may consider a high-power DUV photon source for research in atomic and molecular physics or a high-power EUV radiation source for industrial lithography. A less challenging proof-of-principle test to produce IR radiation using an existing storage ring is also considered.

  15. Very High Energy Electron-positron Colliding Beams for the Study of the Weak Interactions

    CERN Document Server

    Richter, B

    1976-01-01

    We consider the design of very high energy electron-positron colliding-beam storage rings for use primarily as a tool for investigating the weak interactions. These devices appear to be a very powerful tool for determining the properties of these interactions. Experimental possibilities are described, a cost minimization technique is developed, and a model machine is designed to operate at centre-of-mass energies of up to 200 GeV. Costs are discussed, and problems delineated that must be solved before such a machine can be finally designed.

  16. Beam dynamics studies on BEPC-Ⅱstorage rings at the commissioning stage

    Institute of Scientific and Technical Information of China (English)

    QIN Qing; HUANG Nan; LIU Wei-Bin; LIU Yu-Dong; PENG Yue-Mei; QIU Jing; WANG Dou; WANG Xin-Hao; WANG Na; WANG Jiu-Qing; WEI Yuan-Yuan; WEN Xue-Mei; XING Jun; XU Gang; Yu Cheng-Hui; ZHANG Chuang; ZHANG Yuan; ZHAO Zheng; ZHOU De-Min

    2009-01-01

    During the 1st and 2nd stages of the commissioning of the upgrade project of the Beijing Electron Positron Collider(BEPC Ⅱ),which started on Nov.12,2006 and Oct.24,2007,respectively,we got the luminosity one tenth of its design value,provided beams to synchrotron radiation users for about 4 months,and studied beam dynamics as well.In this paper,some beam dynamics studies on the storage rings and their preliminary results are given.

  17. Fourth-generation storage rings

    Energy Technology Data Exchange (ETDEWEB)

    Galayda, J. N.

    1999-11-16

    It seems clear that a linac-driven free-electron laser is the accepted prototype of a fourth-generation facility. This raises two questions: can a storage ring-based light source join the fourth generation? Has the storage ring evolved to its highest level of performance as a synchrotrons light source? The answer to the second question is clearly no. The author thinks the answer to the first question is unimportant. While the concept of generations has been useful in motivating thought and effort towards new light source concepts, the variety of light sources and their performance characteristics can no longer be usefully summed up by assignment of a ''generation'' number.

  18. APS storage ring vacuum system

    Energy Technology Data Exchange (ETDEWEB)

    Niemann, R.C.; Benaroya, R.; Choi, M.; Dortwegt, R.J.; Goeppner, G.A.; Gonczy, J.; Krieger, C.; Howell, J.; Nielsen, R.W.; Roop, B.; Wehrle, R.B.

    1990-01-01

    The Advanced Photon Source synchrotron radiation facility, under construction at the Argonne National Laboratory, incorporates a large ring for the storage of 7 GeV positrons for the generation of photon beams for the facility's experimental program. The Storage Ring's 1104 m circumference is divided into 40 functional sectors. The sectors include vacuum, beam transport, control, acceleration and insertion device components. The vacuum system, which is designed to operate at a pressure of 1 n Torr, consists of 240 connected sections, the majority of which are fabricated from an aluminum alloy extrusion. The sections are equipped with distributed NeG pumping, photon absorbers with lumped pumping, beam position monitors, vacuum diagnostics and valving. The details of the vacuum system design, selected results of the development program and general construction plans are presented. 11 refs., 6 figs., 3 tabs.

  19. Bruno Touschek: particle physicist and father of the electron-positron collider

    CERN Document Server

    Bonolis, Luisa

    2011-01-01

    This article gives a brief outline of the life and works of the Austrian physicist Bruno Touschek, who conceived, proposed and, 50 years ago, brought to completion the construction of AdA, the first electron-positron storage ring. The events which led to the approval of the AdA pro ject and the Franco-Italian collaboration which con- firmed the feasibility of electron-positron storage rings will be recalled. We shall illustrate Bruno Touschek's formation both as a theoretical physicist and as an expert in particle accelerators during the period be- tween the time he had to leave the Vienna Staat Gymnasium in 1938, because of his Jewish origin from the maternal side, until he arrived in Italy in the early 1950s and, in 1960, proposed to build AdA, in Frascati. The events which led to Touschek's collaboration with Rolf Wideroe in the construction of the first European betatron will be de- scribed. The article will make use of a number of unpublished as well as previously unknown documents, which include an earl...

  20. Neutrino Signals in Electron-Capture Storage-Ring Experiments

    Directory of Open Access Journals (Sweden)

    Avraham Gal

    2016-06-01

    Full Text Available Neutrino signals in electron-capture decays of hydrogen-like parent ions P in storage-ring experiments at GSI are reconsidered, with special emphasis placed on the storage-ring quasi-circular motion of the daughter ions D in two-body decays P → D + ν e . It is argued that, to the extent that daughter ions are detected, these detection rates might exhibit modulations with periods of order seconds, similar to those reported in the GSI storage-ring experiments for two-body decay rates. New dedicated experiments in storage rings, or using traps, could explore these modulations.

  1. The cryogenic storage ring CSR.

    Science.gov (United States)

    von Hahn, R; Becker, A; Berg, F; Blaum, K; Breitenfeldt, C; Fadil, H; Fellenberger, F; Froese, M; George, S; Göck, J; Grieser, M; Grussie, F; Guerin, E A; Heber, O; Herwig, P; Karthein, J; Krantz, C; Kreckel, H; Lange, M; Laux, F; Lohmann, S; Menk, S; Meyer, C; Mishra, P M; Novotný, O; O'Connor, A P; Orlov, D A; Rappaport, M L; Repnow, R; Saurabh, S; Schippers, S; Schröter, C D; Schwalm, D; Schweikhard, L; Sieber, T; Shornikov, A; Spruck, K; Sunil Kumar, S; Ullrich, J; Urbain, X; Vogel, S; Wilhelm, P; Wolf, A; Zajfman, D

    2016-06-01

    An electrostatic cryogenic storage ring, CSR, for beams of anions and cations with up to 300 keV kinetic energy per unit charge has been designed, constructed, and put into operation. With a circumference of 35 m, the ion-beam vacuum chambers and all beam optics are in a cryostat and cooled by a closed-cycle liquid helium system. At temperatures as low as (5.5 ± 1) K inside the ring, storage time constants of several minutes up to almost an hour were observed for atomic and molecular, anion and cation beams at an energy of 60 keV. The ion-beam intensity, energy-dependent closed-orbit shifts (dispersion), and the focusing properties of the machine were studied by a system of capacitive pickups. The Schottky-noise spectrum of the stored ions revealed a broadening of the momentum distribution on a time scale of 1000 s. Photodetachment of stored anions was used in the beam lifetime measurements. The detachment rate by anion collisions with residual-gas molecules was found to be extremely low. A residual-gas density below 140 cm(-3) is derived, equivalent to a room-temperature pressure below 10(-14) mbar. Fast atomic, molecular, and cluster ion beams stored for long periods of time in a cryogenic environment will allow experiments on collision- and radiation-induced fragmentation processes of ions in known internal quantum states with merged and crossed photon and particle beams.

  2. The cryogenic storage ring CSR

    Science.gov (United States)

    von Hahn, R.; Becker, A.; Berg, F.; Blaum, K.; Breitenfeldt, C.; Fadil, H.; Fellenberger, F.; Froese, M.; George, S.; Göck, J.; Grieser, M.; Grussie, F.; Guerin, E. A.; Heber, O.; Herwig, P.; Karthein, J.; Krantz, C.; Kreckel, H.; Lange, M.; Laux, F.; Lohmann, S.; Menk, S.; Meyer, C.; Mishra, P. M.; Novotný, O.; O'Connor, A. P.; Orlov, D. A.; Rappaport, M. L.; Repnow, R.; Saurabh, S.; Schippers, S.; Schröter, C. D.; Schwalm, D.; Schweikhard, L.; Sieber, T.; Shornikov, A.; Spruck, K.; Sunil Kumar, S.; Ullrich, J.; Urbain, X.; Vogel, S.; Wilhelm, P.; Wolf, A.; Zajfman, D.

    2016-06-01

    An electrostatic cryogenic storage ring, CSR, for beams of anions and cations with up to 300 keV kinetic energy per unit charge has been designed, constructed, and put into operation. With a circumference of 35 m, the ion-beam vacuum chambers and all beam optics are in a cryostat and cooled by a closed-cycle liquid helium system. At temperatures as low as (5.5 ± 1) K inside the ring, storage time constants of several minutes up to almost an hour were observed for atomic and molecular, anion and cation beams at an energy of 60 keV. The ion-beam intensity, energy-dependent closed-orbit shifts (dispersion), and the focusing properties of the machine were studied by a system of capacitive pickups. The Schottky-noise spectrum of the stored ions revealed a broadening of the momentum distribution on a time scale of 1000 s. Photodetachment of stored anions was used in the beam lifetime measurements. The detachment rate by anion collisions with residual-gas molecules was found to be extremely low. A residual-gas density below 140 cm-3 is derived, equivalent to a room-temperature pressure below 10-14 mbar. Fast atomic, molecular, and cluster ion beams stored for long periods of time in a cryogenic environment will allow experiments on collision- and radiation-induced fragmentation processes of ions in known internal quantum states with merged and crossed photon and particle beams.

  3. The Cryogenic Storage Ring CSR

    CERN Document Server

    von Hahn, Robert; Berg, Felix; Blaum, Klaus; Breitenfeldt, Christian; Fadil, Hisham; Fellenberger, Florian; Froese, Michael; George, Sebastian; Göck, Jürgen; Grieser, Manfred; Grussie, Florian; Guerin, Elisabeth A; Heber, Oded; Herwig, Philipp; Karthein, Jonas; Krantz, Claude; Kreckel, Holger; Lange, Michael; Laux, Felix; Lohmann, Svenja; Menk, Sebastian; Meyer, Christian; Mishra, Preeti M; Novotný, Oldřich; Connor, Aodh P O; Orlov, Dmitry A; Rappaport, Michael L; Repnow, Roland; Saurabh, Sunny; Schippers, Stefan; Schröter, Claus Dieter; Schwalm, Dirk; Schweikhard, Lutz; Sieber, Thomas; Shornikov, Andrey; Spruck, Kaija; Kumar, Sudhakaran Sunil; Ullrich, Joachim; Urbain, Xavier; Vogel, Stephen; Wilhelm, Patrick; Wolf, Andreas; Zajfman, Daniel

    2016-01-01

    An electrostatic cryogenic storage ring, CSR, for beams of anions and cations with up to 300 keV kinetic energy per unit charge has been designed, constructed and put into operation. With a circumference of 35 m, the ion-beam vacuum chambers and all beam optics are in a cryostat and cooled by a closed-cycle liquid helium system. At temperatures as low as (5.5 $\\pm$ 1) K inside the ring, storage time constants of several minutes up to almost an hour were observed for atomic and molecular, anion and cation beams at an energy of 60 keV. The ion-beam intensity, energy-dependent closed-orbit shifts (dispersion) and the focusing properties of the machine were studied by a system of capacitive pickups. The Schottky-noise spectrum of the stored ions revealed a broadening of the momentum distribution on a time scale of 1000 s. Photodetachment of stored anions was used in the beam lifetime measurements. The detachment rate by anion collisions with residual-gas molecules was found to be extremely low. A residual-gas den...

  4. Nuclear Physics Experiments with Ion Storage Rings

    CERN Document Server

    Litvinova, Yu A; Blaum, K; Bosch, F; Brandau, C; Chen, L X; Dillmann, I; Egelhof, P; Geissel, H; Grisenti, R E; Hagmann, S; Heil, M; Heinz, A; Kalantar-Nayestanaki, N; Knöbel, R; Kozhuharov, C; Lestinsky, M; Ma, X W; Nilsson, T; Nolden, F; Ozawa, A; Raabe, R; Reed, M W; Reifarth, R; Sanjari, M S; Schneider, D; Simon, H; Steck, M; Stöhlker, T; Sun, B H; Tu, X L; Uesaka, T; Walker, P M; Wakasugi, M; Weick, H; Winckler, N; Woods, P J; Xu, H S; Yamaguchi, T; Yamaguchi, Y; Zhang, Y H

    2013-01-01

    In the last two decades a number of nuclear structure and astrophysics experiments were performed at heavy-ion storage rings employing unique experimental conditions offered by such machines. Furthermore, building on the experience gained at the two facilities presently in operation, several new storage ring projects were launched worldwide. This contribution is intended to provide a brief review of the fast growing field of nuclear structure and astrophysics research at storage rings.

  5. Beam Measurements in Storage Rings

    Science.gov (United States)

    Hofmann, Albert

    1996-05-01

    Beam measurements in storage rings are made to diagnose performance limitations and to gain knowledge of the beam behavior in view of improvements and to the benefit for other machines. In beam optics the measurement of the orbit or the trajectory with beam position monitors distributed around the ring reveals deflection errors. The overall focusing is checked by measuring the betatron frequency (tune) using a pulse or continuous excitation of the oscillation. Observing this oscillation with all the beam position monitors around the ring the beta function and the betatron phase advance are obtained. This measurement done for different momenta, i.e. RF-frequencies, gives the local chromaticity and its correction. The tune dependence on quadrupole strength gives the value of the local beta function. Synchrotron radiation is a powerful diagnostics tool and can give the beam cross section. Beam instabilities are investigated with similar methods. The growth or damping rates and frequencies of betatron and synchrotron oscillations, observed as a function of intensity, give a convolution of the resistive and reactive part of the transverse and longitudinal impedance with the spectrum of the oscillation mode. Coupled bunch instabilities are caused by narrow band impedances at particular frequencies while single traversal effects, including energy loss and bunch lengthening, are due to a broad band impedance. A model of the impedance can be constructed from such measurements done with different bunch lengths, tunes and other parameters. In some cases the element causing an instability can be identified. The dependence of the orbit and phase advance around the ring on intensity can give the location of impedances. To probe the impedance at very high frequencies the effects on very short bunches or the energy loss of a continuous beam due to its Schottky noise are measured. The beam energy, usually known from magnetic measurements, can be obtained directly with high

  6. Longitudinal dynamics in storage rings

    Energy Technology Data Exchange (ETDEWEB)

    Colton, E.P.

    1986-01-01

    The single-particle equations of motion are derived for charged particles in a storage ring. Longitudinal space charge is included in the potential assuming an infinitely conducting circular beam pipe with a distributed inductance. The framework uses Hamilton's equations with the canonical variables phi and W. The Twiss parameters for longitudinal motion are also defined for the small amplitude synchrotron oscillations. The space-charge Hamiltonian is calculated for both parabolic bunches and ''matched'' bunches. A brief analysis including second-harmonic rf contributions is also given. The final sections supply calculations of dynamical quantities and particle simulations with the space-charge effects neglected.

  7. The cryogenic storage ring project

    Energy Technology Data Exchange (ETDEWEB)

    Hahn, Robert von; Blaum, Klaus; Becker, Arno; Fellenberger, Florian; George, Sebastian; Grieser, Manfred; Grussie, Florian; Herwig, Philipp; Krantz, Claude; Kreckel, Holger; Lange, Michael; Menk, Sebastian; Repnow, Roland; Vogel, Stephen; Wolf, Andreas [Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany); Spruck, Kaija [Justus-Liebig-Universitaet, Giessen (Germany)

    2014-07-01

    At MPIK the electrostatic cryogenic storage ring CSR is nearing completion. At beam energies of 20 to 300 keV per charge unit and 35 m circumference the CSR will allow experiments in a cryogenic environment providing conditions of extremely low vacuum and heat radiation. By using liquid helium at 2 K for cryopumping, the projected vacuum (confirmed at a prototype) lies at 1E-13 mbar or below, ensuring long storage times for slow singly charged and highly charged ions, molecules and clusters. Moreover, phase space cooling by electrons will be implemented. The internal quantum states of molecular and cluster ions can be cooled to low temperature, yielding well defined vibrational and for smaller systems also rotational structures. In the CSR construction, the cryogenic ion beam vacuum system has been set up. Extensive tests confirming the criteria on heat flow, alignment and high-voltage stability were successfully completed on the first quadrant. In addition beam diagnostic units for electric pickup signals and spatial profiles, detectors for neutral and charged fragments, the injection beam line, and an electron cooling device are under construction.

  8. The "g-2" Muon Storage Ring

    CERN Multimedia

    CERN PhotoLab

    1974-01-01

    The "g-2" muon storage ring, shortly before completion in June 1974. Bursts of pions (from a target, hit by a proton beam from the 26 GeV PS) are injected and polarized muons from their decay are captured on a stable orbit. When the muons decay too, their precession in the magnetic field of the storage ring causes a modulation of the decay-electron counting rate, from which the muon's anomalous magnetic moment can be determined. In 1977, the "g-2" magnets were modified to build ICE (Initial Cooling Experiment), a proton and antiproton storage ring for testing stochastic and electron cooling. Later on, the magnets had a 3rd life, when the ion storage ring CELSIUS was built from them in Uppsala. For later use as ICE, see 7711282, 7802099, 7809081,7908242.

  9. Storage rings, internal targets and PEP

    Energy Technology Data Exchange (ETDEWEB)

    Spencer, J.E.

    1986-11-01

    Storage rings with internal targets are described, using PEP as an example. The difference between electrons and heavier particles such as protons, antiprotons, and heavy ions is also discussed because it raises possibilities of bypass insertions for more exotic experiments. PEP is compared to other rings in various contexts to verify the assertion that it is an ideal ring for many fundamental and practical applications that can be carried on simultaneously. (LEW)

  10. LEP - Large Electron Positron Exhibition LEPFest 2000

    CERN Multimedia

    2000-01-01

    The Large Electron-Positron Collider (LEP) is 27 km long. Its four detectors (ALEPH, DELPHI, L3, OPAL) measure precisely what happens in the collisions of electrons and positrons. These conditions only exist-ed in the Universe when it was about 10 -10 sec old.

  11. Storage-ring Electron Cooler for Relativistic Ion Beams

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Fanglei [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Derbenev, Yaroslav [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Douglas, David R. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Guo, Jiquan [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Johnson, Rolland P. [Muons Inc., Batavia, IL (United States); Krafft, Geoffrey A. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Morozov, Vasiliy [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Zhang, Yuhong [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)

    2016-05-01

    Application of electron cooling at ion energies above a few GeV has been limited due to reduction of electron cooling efficiency with energy and difficulty in producing and accelerating a high-current high-quality electron beam. A high-current storage-ring electron cooler offers a solution to both of these problems by maintaining high cooling beam quality through naturally-occurring synchrotron radiation damping of the electron beam. However, the range of ion energies where storage-ring electron cooling can be used has been limited by low electron beam damping rates at low ion energies and high equilibrium electron energy spread at high ion energies. This paper reports a development of a storage ring based cooler consisting of two sections with significantly different energies: the cooling and damping sections. The electron energy and other parameters in the cooling section are adjusted for optimum cooling of a stored ion beam. The beam parameters in the damping section are adjusted for optimum damping of the electron beam. The necessary energy difference is provided by an energy recovering SRF structure. A prototype linear optics of such storage-ring cooler is presented.

  12. Inauguration ceremony for the Intersecting Storage Rings

    CERN Multimedia

    1971-01-01

    The inauguration ceremony for the Intersecting Storage Rings (ISR) was held on 16 October 1971. Kjell Johnsen is seen in the picture handing a symbolic key to the ISR to Edoardo Amaldi. From left to right on the podium: Victor Frederik Weisskopf, former Director-General; M Antonioz; Willibald Jentschke as Director-General of CERN, and on the other side Werner Heisenberg.

  13. Electron Storage Ring Development for ICS Sources

    Energy Technology Data Exchange (ETDEWEB)

    Loewen, Roderick [Lyncean Technologies, Inc., Palo Alto, CA (United States)

    2015-09-30

    There is an increasing world-wide interest in compact light sources based on Inverse Compton Scattering. Development of these types of light sources includes leveraging the investment in accelerator technology first developed at DOE National Laboratories. Although these types of light sources cannot replace the larger user-supported synchrotron facilities, they offer attractive alternatives for many x-ray science applications. Fundamental research at the SLAC National Laboratory in the 1990’s led to the idea of using laser-electron storage rings as a mechanism to generate x-rays with many properties of the larger synchrotron light facilities. This research led to a commercial spin-off of this technology. The SBIR project goal is to understand and improve the performance of the electron storage ring system of the commercially available Compact Light Source. The knowledge gained from studying a low-energy electron storage ring may also benefit other Inverse Compton Scattering (ICS) source development. Better electron storage ring performance is one of the key technologies necessary to extend the utility and breadth of applications of the CLS or related ICS sources. This grant includes a subcontract with SLAC for technical personnel and resources for modeling, feedback development, and related accelerator physics studies.

  14. First interactions from the Intersecting Storage Rings

    CERN Multimedia

    1971-01-01

    On 27 January 1971, Kjell Johnsen, who led the construction team which built the Intersecting Storage Rings (ISR), announced that the first ever interactions from colliding protons had been recorded. On the left are Franco Bonaudi, who was responsible for the civil engineering and Dirk Neet, who later took charge of ISR operations.

  15. Modeling colliding beams with an element by element representation of the storage ring guide field

    Directory of Open Access Journals (Sweden)

    D. L. Rubin

    2006-01-01

    Full Text Available A detailed model of the Cornell Electron Storage Ring (CESR guide field, including beam-beam interaction computed in the weak-strong regime, is the basis for a multiturn simulation of luminosity. The simulation reproduces the dependence of luminosity on bunch current that is measured in the storage ring, at both high-energy (5.3   GeV/beam and in the wiggler-dominated low energy (CESR-c configuration (1.9   GeV/beam. Dynamics are determined entirely by the physics of propagation through the individual guide field elements with no free parameters. Energy dependence of the compensation of the transverse coupling introduced by the experimental solenoid is found to significantly degrade specific luminosity. The simulation also indicates a strong dependence of limiting beam-beam tune shift parameter on the geometric mean of synchrotron tune and bunch length.

  16. Perspective for a compact electrostatic storage ring : Miniature quadrilateral electrostatic storage ring

    OpenAIRE

    El Ghazaly, Mohamed ,

    2013-01-01

    International audience; A flexible, compact-sized electrostatic storage ring is being designed at the King Abdulaziz City for Science and Technology (KACST). The design features a quadratic shaped ring with four 90° bending corners and relies exclusively on quadrupoles to act on the stored ion beam.

  17. Storage-ring Electron Cooler for Relativistic Ion Beams

    CERN Document Server

    Lin, F; Douglas, D; Guo, J; Johnson, R P; Krafft, G; Morozov, V S; Zhang, Y

    2016-01-01

    Application of electron cooling at ion energies above a few GeV has been limited due to reduction of electron cooling efficiency with energy and difficulty in producing and accelerating a high-current high-quality electron beam. A high-current storage-ring electron cooler offers a solution to both of these problems by maintaining high cooling beam quality through naturally-occurring synchrotron radiation damping of the electron beam. However, the range of ion energies where storage-ring electron cooling can be used has been limited by low electron beam damping rates at low ion energies and high equilibrium electron energy spread at high ion energies. This paper reports a development of a storage ring based cooler consisting of two sections with significantly different energies: the cooling and damping sections. The electron energy and other parameters in the cooling section are adjusted for optimum cooling of a stored ion beam. The beam parameters in the damping section are adjusted for optimum damping of the...

  18. Asymmetric Laser Radiant Cooling in Storage Rings

    CERN Document Server

    Bulyak, E V; Zimmermann, F

    2011-01-01

    Laser pulses with small spatial and temporal dimensions can interact with a fraction of the electron bunches circulating in Compton storage rings. We studied synchrotron dynamics of such bunches when laser photons scatter off from the electrons with energy higher than the synchronous energy. In this case of ‘asymmetric cooling', as shown theoretically, the stationary energy spread is much smaller than under conditions of regular scattering; the oscillations are damped faster. Coherent oscillations of large amplitude may be damped in one synchrotron period, which makes this method feasible for injection the bunches into a ring in the longitudinal phase space. The theoretical results are validated with simulations.

  19. Feasibility of a ring FEL at low emittance storage rings

    Energy Technology Data Exchange (ETDEWEB)

    Agapov, I., E-mail: ilya.agapov@xfel.eu

    2015-09-01

    A scheme for generating coherent radiation at latest generation low emittance storage rings such as PETRA III at DESY (Balewski et al., 2004 [1]) is proposed. The scheme is based on focusing and subsequent defocusing of the electron beam in the longitudinal phase space at the undulator location. The expected performance characteristics are estimated for radiation in the wavelength range of 500–1500 eV. It is shown that the average brightness is increased by several orders of magnitude compared to spontaneous undulator radiation, which can open new perspectives for photon-hungry soft X-ray spectroscopy techniques.

  20. Chaotic dynamics in a storage-ring Free Electron Laser

    CERN Document Server

    De Ninno, G; Bruni, C; Couprie, Marie Emmanuelle

    2002-01-01

    The temporal dynamics of a storage-ring Free Electron Laser is here investigated with particular attention to the case in which an external modulation is applied to the laser-electron beam detuning. The system is shown to produce bifurcations, multi-furcations as well as chaotic regimes. The peculiarities of this phenomenon with respect to the analogous behavior displayed by conventional laser sources are pointed out. Theoretical results, obtained by means of a phenomenological model reproducing the evolution of the main statistical parameters of the system, are shown to be in a good agreement with experiments carried out on the Super-ACO Free Electron Laser.

  1. Extracting the size of the cosmic electron-positron anomaly

    OpenAIRE

    Auchettl, Katie; Balázs, Csaba

    2011-01-01

    We isolated the anomalous part of the cosmic electron-positron flux within a Bayesian likelihood analysis. Using 219 recent cosmic ray spectral data points, we inferred the values of selected cosmic ray propagation parameters. In the context of the propagation model coded in GalProp, we found a significant tension between the electron positron related and the rest of the fluxes. Interpreting this tension as the presence of an anomalous component in the electron-positron related data, we calcu...

  2. Two-photon exchange contribution in elastic electron-proton scattering, experiment at the VEPP-3 storage ring

    Directory of Open Access Journals (Sweden)

    Nikolenko D.M.

    2014-03-01

    Full Text Available We describe a precise measurement of the ratio of the (e+ p to (e− p elastic scattering cross sections. This comparison is sensitive to the effect of two-photon exchange contributions which may be the cause for inconsistent extractions of the proton form factors obtained using different methods. The experiment was performed at storage ring VEPP–3, Novosibirsk at energies of positron/electron beams of 1.0 and 1.6 GeV with electron/positron scattering angles θ = 65÷105° for the first case and 15÷25° and 55÷75° for the second case. Details of the experiment and the preliminary results are presented.

  3. Heavy ion storage ring without linear dispersion

    Directory of Open Access Journals (Sweden)

    Masahiro Ikegami

    2004-12-01

    Full Text Available A possible method to realize a dispersion-free storage ring is described. The simultaneous use of a magnetic field B and an electric field E in bending regions, where the two fields are set perpendicular to each other, enables us to control the effect of momentum dispersion. When the relation (1+1/γ_{0}^{2}E(ρ=-v_{0}×B is satisfied for a beam with the velocity v_{0}, the linear dispersion can be completely eliminated all around the ring. It is shown that the acceleration and deceleration induced by the electrostatic deflector counteracts the heating mechanism due to the shearing force from dipole magnets. The dispersion-free system is thus beneficial to producing ultracold beams. It looks probable that the technique will allow one to achieve three-dimensional crystalline beams. At ICR Kyoto University, an ion cooler storage ring S-LSR oriented for various beam physics purposes is now under construction. The application of the present idea to S-LSR is discussed and the actual design of the dispersionless bend is given.

  4. FLSR - The Frankfurt low energy storage ring

    Science.gov (United States)

    Stiebing, K. E.; Alexandrov, V.; Dörner, R.; Enz, S.; Kazarinov, N. Yu.; Kruppi, T.; Schempp, A.; Schmidt Böcking, H.; Völp, M.; Ziel, P.; Dworak, M.; Dilfer, W.

    2010-02-01

    An electrostatic storage ring for low-energy ions with a design energy of 50 keV is presently being set up at the Institut für Kernphysik der Johann Wolfgang Goethe-Universität Frankfurt am Main, Germany (IKF). This new device will provide a basis for new experiments on the dynamics of ionic and molecular collisions, as well as for high precision and time resolved laser spectroscopy. In this article, the design parameters of this instrument are reported.

  5. Introductory statistical mechanics for electron storage rings

    Science.gov (United States)

    Jowett, John M.

    1987-02-01

    These lectures concentrate on statistical phenomena in electron storage rings. A stored electron beam is a dissipative, fluctuating system far from equilibrium whose mathematical description can be based upon non-equilibrium statistical mechanics. Stochastic differential equations are used to describe the quantum fluctuations of synchrotron radiation which is the main cause of randomness in electron dynamics. Fluctuating radiation reaction forces can be described via stochastic terms in Hamilton's equations of motion. Normal modes of particle motion, radiation damping effects, quantum diffusion in single-particle phase space are all discussed in this statistical formalism. (AIP)

  6. APS Storage Ring vacuum chamber fabrication

    Energy Technology Data Exchange (ETDEWEB)

    Goeppner, G.A.

    1990-01-01

    The 1104-m circumference Advanced Photon Source Storage Ring Vacuum System is composed of 240 individual sections, which are fabricated from a combination of aluminum extrusions and machined components. The vacuum chambers will have 3800 weld joints, each subject to strict vacuum requirements, as well as a variety of related design criteria. The vacuum criteria and chamber design are reviewed, including a discussion of the weld joint geometries. The critical fabrication process parameters for meeting the design requirements are discussed. The experiences of the prototype chamber fabrication program are presented. Finally, the required facilities preparation for construction activity is briefly described. 6 refs., 6 figs., 1 tab.

  7. Storage ring electric dipole moment experiments

    Science.gov (United States)

    Morse, William M.; Storage Ring EDM Collaboration

    2013-10-01

    Dedicated electric dipole moment (edm) searches have been done only for neutral systems. We discuss in this talk dedicated storage ring proposals for measuring edms of charged particles. The statistical error dominates over the systematic error for the neutron and mercury atom edm searches. Large numbers of particles are available today from modern polarized sources at several accelerators. A proposed proton edm experiment at BNL would improve the present proton edm limit by a factor of 104. A "precursor" deuteron edm experiment has been proposed at COSY, Juelich, Germany. This would be the first measurement of the deuteron edm.

  8. Electron-positron outflow from black holes

    CERN Document Server

    Van Putten, M H P M

    2000-01-01

    Gamma-ray bursts (GRBs) appear as the brightest transient phenomena in the Universe. The nature of the central engine in GRBs is a missing link in the theory of fireballs to their stellar mass progenitors. Here it is shown that rotating black holes produce electron-positron outflow when brought into contact with a strong magnetic field. The outflow is produced by a coupling of the spin of the black hole to the orbit of the particles. For a nearly extreme Kerr black hole, particle outflow from an initial state of electrostatic equilibrium has a normalized isotropic emission of $\\sim external magnetic field strength, B_c=4.4 x 10^{13}G, and M is the mass of the black hole. This initial outflow has a half-opening angle given.

  9. Nonlinear dynamics of electron-positron clusters

    CERN Document Server

    Manfredi, Giovanni; Haas, Fernando; 10.1088/1367-2630/14/7/075012

    2012-01-01

    Electron-positron clusters are studied using a quantum hydrodynamic model that includes Coulomb and exchange interactions. A variational Lagrangian method is used to determine their stationary and dynamical properties. The cluster static features are validated against existing Hartree-Fock calculations. In the linear response regime, we investigate both dipole and monopole (breathing) modes. The dipole mode is reminiscent of the surface plasmon mode usually observed in metal clusters. The nonlinear regime is explored by means of numerical simulations. We show that, by exciting the cluster with a chirped laser pulse with slowly varying frequency (autoresonance), it is possible to efficiently separate the electron and positron populations on a timescale of a few tens of femtoseconds.

  10. The beam energy feedback system for Beijing electron positron collider II linac.

    Science.gov (United States)

    Wang, S; Iqbal, M; Chi, Y; Liu, R; Huang, X

    2017-03-01

    A beam-energy feedback system has been developed for the injection linac to meet the beam quality needed for the Beijing electron positron collider II storage ring. This paper describes the implementation and commissioning of this system in detail. The system consists of an energy measurement unit, application software, and an actuator unit. A non-intersecting beam energy monitor was developed to allow real-time online energy adjustment. The beam energy adjustment is achieved by adjusting the output microwave phase of the RF power source station. The phase control mechanism has also been modified, and a new control method taking the return difference of the phase shifter into account is used to improve the system's performance. This system achieves the design aim and can adjust the beam center energy with a rate of 2 Hz. With the energy feedback system, the stability of the injection rate is better; the fluctuation range is reduced from 20 mA/min to 10 mA/min, while the stability of the beam center energy is maintained within ±0.1%.

  11. EXTRACTING THE SIZE OF THE COSMIC ELECTRON-POSITRON ANOMALY

    Energy Technology Data Exchange (ETDEWEB)

    Auchettl, Katie; Balazs, Csaba [Monash Centre for Astrophysics, Monash University, Victoria 3800 (Australia)

    2012-04-20

    We isolated the anomalous part of the cosmic electron-positron flux within a Bayesian likelihood analysis. Using 219 recent cosmic-ray spectral data points, we inferred the values of selected cosmic-ray propagation parameters. In the context of the propagation model coded in GalProp, we found a significant tension between the electron-positron related and the rest of the fluxes. Interpreting this tension as the presence of an anomalous component in the electron-positron related data, we calculated background predictions for PAMELA and Fermi-LAT based on the non-electron-positron related fluxes. We found a deviation between the data and the predicted background even when uncertainties, including systematics, were taken into account. We identified this deviation with the anomalous electron-positron contribution. We briefly compared this model-independent signal to some theoretical results predicting such an anomaly.

  12. Search for electric dipole moments in storage rings

    Directory of Open Access Journals (Sweden)

    Lenisa Paolo

    2016-01-01

    Full Text Available The JEDI collaboration aims at making use of storage ring to provide the most precise measurement of the electric dipole moments of hadrons. The method makes exploits a longitudinal polarized beam. The existence an electric dipole moment would generate a torque slowly twisting the particle spin out of plan of the storage ring into the vertical direction. The observation of non zero electric dipole moment would represent a clear sign of new physics beyond the Standard Model. Feasiblity tests are presently undergoing at the COSY storage ring Forschungszentrum Jülich (Germany, to develop the novel techniques to be implemented in a future dedicated storage ring.

  13. Characterization of a new electrostatic storage ring for photofragmentation experiments

    Energy Technology Data Exchange (ETDEWEB)

    Pedersen, H. B., E-mail: hbjp@phys.au.dk; Svendsen, A.; Harbo, L. S.; Kiefer, H. V.; Kjeldsen, H.; Lammich, L.; Andersen, L. H. [Department of Physics and Astronomy, Aarhus University, DK-8000 Aarhus C (Denmark); Toker, Y. [Departement of Physics, Bar Ilan University, Ramat Gan 5290002 (Israel)

    2015-06-15

    We describe the design of and the first commissioning experiments with a newly constructed electrostatic storage ring named SAPHIRA (Storage Ring in Aarhus for PHoton-Ion Reaction Analysis). With an intense beam of Cu{sup −} at 4 keV, the storage ring is characterized in terms of the stored ion beam decay rate, the longitudinal spreading of an injected ion bunch, as well as the direct measurements of the transverse spatial distributions under different conditions of storage. The ion storage stability in SAPHIRA was investigated systematically in a selected region of its electrical configuration space.

  14. The MAX IV storage ring project.

    Science.gov (United States)

    Tavares, Pedro F; Leemann, Simon C; Sjöström, Magnus; Andersson, Ake

    2014-09-01

    The MAX IV facility, currently under construction in Lund, Sweden, features two electron storage rings operated at 3 GeV and 1.5 GeV and optimized for the hard X-ray and soft X-ray/VUV spectral ranges, respectively. A 3 GeV linear accelerator serves as a full-energy injector into both rings as well as a driver for a short-pulse facility, in which undulators produce X-ray pulses as short as 100 fs. The 3 GeV ring employs a multibend achromat (MBA) lattice to achieve, in a relatively short circumference of 528 m, a bare lattice emittance of 0.33 nm rad, which reduces to 0.2 nm rad as insertion devices are added. The engineering implementation of the MBA lattice raises several technological problems. The large number of strong magnets per achromat calls for a compact design featuring small-gap combined-function magnets grouped into cells and sharing a common iron yoke. The small apertures lead to a low-conductance vacuum chamber design that relies on the chamber itself as a distributed copper absorber for the heat deposited by synchrotron radiation, while non-evaporable getter (NEG) coating provides for reduced photodesorption yields and distributed pumping. Finally, a low main frequency (100 MHz) is chosen for the RF system yielding long bunches, which are further elongated by passively operated third-harmonic Landau cavities, thus alleviating collective effects, both coherent (e.g. resistive wall instabilities) and incoherent (intrabeam scattering). In this paper, we focus on the MAX IV 3 GeV ring and present the lattice design as well as the engineering solutions to the challenges inherent to such a design. As the first realisation of a light source based on the MBA concept, the MAX IV 3 GeV ring offers an opportunity for validation of concepts that are likely to be essential ingredients of future diffraction-limited light sources.

  15. Astrochemistry at the Cryogenic Storage Ring

    Science.gov (United States)

    Kreckel, Holger; Becker, Arno; Blaum, Klaus; Breitenfeldt, Christian; George, Sebastian; Göck, Jürgen; Grieser, Manfred; Grussie, Florian; Guerin, Elisabeth; Heber, Oded; Karthein, Jonas; Krantz, Claude; Meyer, Christian; Mishra, Preeti; Novotny, Oldrich; O'Connor, Aodh; Saurabh, Sunny; Schippers, Stefan; Spruck, Kaija; Kumar, S. Sunil; Urbain, Xavier; Vogel, Stephen; von Hahn, Robert; Wilhelm, Patrick; Wolf, Andreas; Zajfman, Daniel

    2017-01-01

    Almost 200 different molecular species have been identified in space, and this number continues to grow steadily. This surprising molecular diversity bears witness to an active reaction network, in which molecular ions are the main drivers of chemistry in the gas phase. To study these reactions under controlled conditions in the laboratory is a major experimental challenge. The new Cryogenic Storage Ring (CSR) that has recently been commissioned at the Max Planck Institute for Nuclear Physics in Heidelberg will serve as an ideal testbed to study cold molecular ions in the gas phase. With residual gas densities of CSR will allow for merged beams collision studies involving molecular ions, neutral atoms, free electrons and photons under true interstellar conditions.

  16. Electron-Positron Flows around Magnetars

    Science.gov (United States)

    Beloborodov, Andrei M.

    2013-11-01

    The twisted magnetospheres of magnetars must sustain a persistent flow of electron-positron plasma. The flow dynamics is controlled by the radiation field around the hot neutron star. The problem of plasma motion in the self-consistent radiation field is solved using the method of virtual beams. The plasma and radiation exchange momentum via resonant scattering and self-organize into the "radiatively locked" outflow with a well-defined, decreasing Lorentz factor. There is an extended zone around the magnetar where the plasma flow is ultra-relativistic; its Lorentz factor is self-regulated so that it can marginally scatter thermal photons. The flow becomes slow and opaque in an outer equatorial zone, where the decelerated plasma accumulates and annihilates; this region serves as a reflector for the thermal photons emitted by the neutron star. The e ± flow carries electric current, which is sustained by a moderate induced electric field. The electric field maintains a separation between the electron and positron velocities, against the will of the radiation field. The two-stream instability is then inevitable, and the induced turbulence can generate low-frequency emission. In particular, radio emission may escape around the magnetic dipole axis of the star. Most of the flow energy is converted to hard X-ray emission, which is examined in an accompanying paper.

  17. Electron-positron flows around magnetars

    CERN Document Server

    Beloborodov, Andrei M

    2012-01-01

    The twisted magnetospheres of magnetars must sustain a persistent flow of electron-positron plasma. The flow dynamics is controlled by the radiation field around the hot neutron star. The problem of plasma motion in the self-consistent radiation field is solved using the method of virtual beams. The plasma and radiation exchange momentum via resonant scattering and self-organize into the "radiatively locked" outflow with a well-defined, decreasing Lorentz factor. There is an extended zone around the magnetar where the plasma flow is ultra-relativistic; its Lorentz factor is self-regulated so that it can marginally scatter thermal photons. The flow becomes slow and opaque in an outer equatorial zone, where the decelerated plasma accumulates and annihilates; this region serves as a reflector for the thermal photons emitted by the neutron star. The e+- flow carries electric current, which is sustained by a moderate induced electric field. The electric field maintains a separation between the electron and positro...

  18. ELECTRON-POSITRON FLOWS AROUND MAGNETARS

    Energy Technology Data Exchange (ETDEWEB)

    Beloborodov, Andrei M., E-mail: amb@phys.columbia.edu [Physics Department and Columbia Astrophysics Laboratory, Columbia University, 538 West 120th Street New York, NY 10027 (United States)

    2013-11-10

    The twisted magnetospheres of magnetars must sustain a persistent flow of electron-positron plasma. The flow dynamics is controlled by the radiation field around the hot neutron star. The problem of plasma motion in the self-consistent radiation field is solved using the method of virtual beams. The plasma and radiation exchange momentum via resonant scattering and self-organize into the 'radiatively locked' outflow with a well-defined, decreasing Lorentz factor. There is an extended zone around the magnetar where the plasma flow is ultra-relativistic; its Lorentz factor is self-regulated so that it can marginally scatter thermal photons. The flow becomes slow and opaque in an outer equatorial zone, where the decelerated plasma accumulates and annihilates; this region serves as a reflector for the thermal photons emitted by the neutron star. The e {sup ±} flow carries electric current, which is sustained by a moderate induced electric field. The electric field maintains a separation between the electron and positron velocities, against the will of the radiation field. The two-stream instability is then inevitable, and the induced turbulence can generate low-frequency emission. In particular, radio emission may escape around the magnetic dipole axis of the star. Most of the flow energy is converted to hard X-ray emission, which is examined in an accompanying paper.

  19. Unicell structure for superconducting storage rings

    Energy Technology Data Exchange (ETDEWEB)

    Danby, G.; DeVito, B.; Jackson, J.; Keohane, G.; Lee, Y.Y.; Phillips, R.; Plate, S.; Repeta, L.; Skaritka, J.; Smith, L.

    1985-01-01

    Mechanically integrated, magnetically decoupled storage rings were designed for a heavy ion collider for 100 GeV/amu Au, at B = 2.7T. New concepts were developed, including detailed engineering design and cost estimates. A ''unicell'' contains a half-cell of both rings within a single He vessel. The unicell design is optimized for economical mass production. Survey pads welded to the laminations provide external fiducials to locate the magnet cores. Roller bearing self aligning supports accommodate cool-down shrinkage. The design tolerates relative motion of components resulting from longitudinal shrinkage in the approx.15 m long unicell without affecting performance. Magnetic and physical lengths are the same, eliminating waste space. ''Achromatic'' quadrupoles with sextupoles at both ends are located on a common precision beam tube which aligns and supports a pick-up electrode. The unicell accommodates longer dipoles compared to conventional designs, reducing B/sub max/, stored energy, and the volume of iron and superconductor. Applications to future machines will be discussed.

  20. Unicell structure for superconducting storage rings

    Energy Technology Data Exchange (ETDEWEB)

    Danby, G.; DeVito, B.; Jackson, J.; Keohane, G.; Lee, Y.Y.; Phillips, R.; Plate, S.; Repeta, L.; Skaritka, J.; Smith, L.

    1985-10-01

    Mechanically integrated, magnetically decoupled storage rings were designed for a heavy ion collider for 100 GeV/amu Au, at B=2.7T. New concepts were developed, including detailed engineering design and cost estimates. A ''unicell'' contains a half-cell of both rings within a single He vessel. The unicell design is optimized for economical mass production. Survey pads welded to the laminations provide external fiducials to locate the magnet cores. Roller bearing self aligning supports accommodate cool-down shrinkage. The design tolerates relative motion of components resulting from longitudinal shrinkage in the about15 m long unicell without affecting performance. Magnetic and physical lengths are the same, eliminating waste space. ''Achromatic'' quadrupoles with sextupoles at both ends are located on a common precision beam tube which aligns and supports a pick-up electrode. The unicell accommodates longer dipoles compared to conventional designs, reducing B /SUB max'/ stored energy, and the volume of iron and superconductor. Applications to future machines will be discussed.

  1. Design study of the storage ring EUTERPE

    Science.gov (United States)

    Xi, Boling; Botman, J. I. M.; Timmermans, C. J.; Hagedoorn, H. L.

    1992-05-01

    At present the 400 MeV electron storage ring EUTERPE is being constructed at the Eindhoven University of Technology. It is a university project set up for studies of charged particle beam dynamics and applications of synchroton radiation, and for the education of students in these fields. The design of the ring is described in this paper. Considering the requirements of users in different fields, a lattice based on a so-called triple bend achromat structure with a high flexibility has been chosen. With this lattice, different optical options, including the HBSB (high brightness, small beam), the SBL (short bunch length) and the HLF (high light flux) modes can be realized. A small emittance of 7 nm rad and a short bunch length of the order of several mm can be achieved. In the first phase the synchrotron radiation in the UV and XUV region (the critical wavelength is 8.3 nm) will be provided from the regular dipole magnets. Later on, a 10 T wiggler magnet and other special inserters will be added, and other applications and beam dynamics studies will be feasible. Bending magnets are of the parallel faced C configuration. The effective aperture of the vacuum chamber is 2.3 cm (vertical) in the bending magnets and 4.7 cm elsewhere with a working vacuum condition of 10-9 Torr. Collective effects have been studied initially. First calculations indicate that a lifetime of several hours, influenced by the Touschek effect and residual gas scattering will be achievable for a 200 mA beam in the HLF mode for the standard rf parameters. A 70 MeV racetrack microtron will serve as injector for the ring.

  2. Bunch transverse emittance increase in electron storage rings

    Institute of Scientific and Technical Information of China (English)

    GAO Jie

    2009-01-01

    In this paper a theoretical framework to estimate the bunch transverse emittance growing in electron storage rings due to short range transverse wakefield of the machine is established. New equilibrium emittance equations are derived and applied to explain the experimentally obtained results in ATF damping ring. This equation will be useful for linear collider damping ring design.

  3. Multi-pair states in electron-positron pair creation

    Science.gov (United States)

    Wöllert, Anton; Bauke, Heiko; Keitel, Christoph H.

    2016-09-01

    Ultra strong electromagnetic fields can lead to spontaneous creation of single or multiple electron-positron pairs. A quantum field theoretical treatment of the pair creation process combined with numerical methods provides a description of the fermionic quantum field state, from which all observables of the multiple electron-positron pairs can be inferred. This allows to study the complex multi-particle dynamics of electron-positron pair creation in-depth, including multi-pair statistics as well as momentum distributions and spin. To illustrate the potential benefit of this approach, it is applied to the intermediate regime of pair creation between nonperturbative Schwinger pair creation and perturbative multiphoton pair creation where the creation of multi-pair states becomes nonnegligible but cascades do not yet set in. Furthermore, it is demonstrated how spin and helicity of the created electrons and positrons are affected by the polarization of the counterpropagating laser fields, which induce the creation of electron-positron pairs.

  4. Study of electron-positron interactions

    Energy Technology Data Exchange (ETDEWEB)

    Abashian, A.; Gotow, K.; Philonen, L.

    1990-09-15

    For the past seven years, this group has been interested in the study of tests of the Standard Model of Electroweak interactions. The program has centered about the AMY experiment which examines the nature of the final state products in electron-positron collisions in the center of mass energy range near 60 GeV. Results of these measurements have shown a remarkable consistency with the predictions of the minimal model of 3 quark and lepton generations and single charged and neutral intermediate bosons. No new particles or excited states have been observed nor has any evidence for departures in cross sections or angular asymmetries from expectations been observed. These conclusions have been even more firmly established by the higher energy results from the LEP and SLC colliders at center of mass energies of about 90 GeV. Our focus is shifting to the neutrino as a probe to electroweak interactions. The relative merit of attempting to observe neutrinos from point sources versus observing neutrinos generally is not easy to predict. The improved ability to interpret is offset by the probably episodic nature of the emission and irreproducibility of the results. In this phase of development, it is best to be sensitive to both sources of neutrinos. As a second phase of our program at Virginia Tech, we are studying the feasibility of detecting cosmic ray neutrinos in a proposed experiment which we have called NOVA. the results of the test setup will be instrumental in developing an optimum design. A third program we are involved in is the MEGA experiment at Los Alamos, an experiment to place a limit on the rate of muon decay to electron plus photon which is forbidden by the Standard Model.

  5. VUV optical ring resonator for Duke storage ring free electron laser

    Energy Technology Data Exchange (ETDEWEB)

    Park, S.H.; Litvinenko, V.N.; Madey, J.M.J. [Duke Univ., Durham, NC (United States)] [and others

    1995-12-31

    The conceptual design of the multifaceted-mirror ring resonator for Duke storage ring VUV FEL is presented. The expected performance of the OK-4 FEL with ring resonator is described. We discuss in this paper our plans to study reflectivity of VUV mirrors and their resistivity to soft X-ray spontaneous radiation from OK-4 undulator.

  6. Calibration of the linear optics in the SSRF storage ring

    Institute of Scientific and Technical Information of China (English)

    TIAN Shunqiang; LIU Guimin; ZHANG Wenzhi; LI Haohu; ZHANG Manzhou; HOU Jie; CHEN Guangling

    2008-01-01

    Phase Ⅰ commissioning of the SSRF storage ring at 3.0 GeV was ended with encouraging results. Distortions and calibrations of the linear optics during the storage ring commissioning are discussed in this paper. The calibration procedure has reduced sextupole-additional focusing effects by minimizing closed orbit deviation and corrected quadrupole magnetic coefficients with the linear optics from closed orbit (LOCO) technique. After fitting the closed orbit response matrix, linear optics of the storage ring is substantially corrected, and the measured parameters agree well with the design. Four optics modes were commissioned, and relevant machine physics studies were carried out. Their results are summarized.

  7. Design of a novel electrostatic ion storage ring at KACST

    Energy Technology Data Exchange (ETDEWEB)

    El Ghazaly, M.O.A., E-mail: maelghazaly@kacst.edu.sa [National Center for Mathematics and Physics (NCMP), King Abdulaziz City for Sciences and Technology (KACST), P.O. Box 6086, Riyadh 11442 (Saudi Arabia); Alshammari, S.M. [National Center for Mathematics and Physics (NCMP), King Abdulaziz City for Sciences and Technology (KACST), P.O. Box 6086, Riyadh 11442 (Saudi Arabia); Welsch, C.P. [Cockcroft Institute and the University of Liverpool (United Kingdom); Alharbi, H.H. [National Center for Mathematics and Physics (NCMP), King Abdulaziz City for Sciences and Technology (KACST), P.O. Box 6086, Riyadh 11442 (Saudi Arabia)

    2013-05-01

    A new electrostatic storage ring for beams at energies up to 30 keV·q is currently under development at the National Centre for Mathematics and Physics (NCMP), King Abdulaziz City for Science and Technology (KACST). The ring design is based on the existing electrostatic storage rings, but stretches significantly beyond them in that it shall form the core of a unique flexible experimental facility at KACST. The lattice of this ring has been designed in a way that enables the use of state-of-the-art experimental methods to study electron–ion, laser-ion, and ion-neutral beams interactions. The lattice design also allows for a future upgrade of the ring to a double storage ring structure that would enable ion–ion beam interactions to be performed. In this paper, we present the design of this ring with a focus on beam dynamics calculations for the 7° single-bend racetrack layout. The study is principally based on the SIMION8 program. We complemented this study further by using purpose-written routine and MAD-X simulation code. An in-depth investigation into beam stability under consideration of non-linear field components in the electrostatic optical elements, is presented. Finally, different working points and stability regions are discussed. -- Highlights: ► The design for a highly flexible electrostatic storage ring is carried out. ► It is shown this design can be upgraded to a double storage ring structure. ► SIMION can be used in ray-tracing simulations to compute aberrations in the ring. ► Non-linear effects in an electrostatic ring can potentially disturb the stored beam. ► An electrostatic ring can store low-energy beams in spite of existing fringe fields.

  8. Physics issues in diffraction limited storage ring design

    Institute of Scientific and Technical Information of China (English)

    FAN Wei; BAI ZhengHe; GAO WeiWei; FENG GuangYao; LI WeiMin; WANG Lin; HE DuoHui

    2012-01-01

    Diffraction limited electron storage ring is considered a promising candidate for future light sources,whose main characteristics are higher brilliance,better transverse coherence and better stability.The challenge of diffraction limited storage ring design is how to achieve the ultra low beam emittance with acceptable nonlinear performance.Effective linear and nonlinear parameter optimization methods based on Artificial Intelligence were developed for the storage ring physical design.As an example of application,partial physical design of HALS (Hefei Advanced Light Source),which is a diffraction limited VUV and soft X-ray light source,was introduced.Severe emittance growth due to the Intra Beam Scattering effect,which is the main obstacle to achieve ultra low emittance,was estimated quantitatively and possible cures were discussed.It is inspiring that better performance of diffraction limited storage ring can be achieved in principle with careful parameter optimization.

  9. Physics issues in diffraction limited storage ring design

    Science.gov (United States)

    Fan, Wei; Bai, ZhengHe; Gao, WeiWei; Feng, GuangYao; Li, WeiMin; Wang, Lin; He, DuoHui

    2012-05-01

    Diffraction limited electron storage ring is considered a promising candidate for future light sources, whose main characteristics are higher brilliance, better transverse coherence and better stability. The challenge of diffraction limited storage ring design is how to achieve the ultra low beam emittance with acceptable nonlinear performance. Effective linear and nonlinear parameter optimization methods based on Artificial Intelligence were developed for the storage ring physical design. As an example of application, partial physical design of HALS (Hefei Advanced Light Source), which is a diffraction limited VUV and soft X-ray light source, was introduced. Severe emittance growth due to the Intra Beam Scattering effect, which is the main obstacle to achieve ultra low emittance, was estimated quantitatively and possible cures were discussed. It is inspiring that better performance of diffraction limited storage ring can be achieved in principle with careful parameter optimization.

  10. Thermal analysis of the beam missteering in APS storage ring

    Energy Technology Data Exchange (ETDEWEB)

    Sheng, I.C.; Howell, J.; Sharma, S.

    1993-08-01

    Several bending magnet beam missteering cases have been investigated for the 7-GeV storage ring of the Advanced Photon Source (APS). One of the critical missteering events is presented in this paper. Finite element analyses are performed to solve for both temperature and stress fields. Thermally induced deflections are determined by using beam bending theory. A safe current limit is established for the storage ring chambers.

  11. Estimates of CSR Instability Thresholds for Various Storage Rings

    CERN Document Server

    Zimmermann, Frank

    2010-01-01

    We review the key predictions and conditions by several authors for the onset of longitudinal instabilities due to coherent synchrotron radiation (CSR), and evaluate them numerically for various storage rings, namely the KEKB High Energy Ring (HER) & Low Energy Ring (LER), SuperKEKB HER & LER, old and new designs of the SuperKEKB Damping Ring (DR), SuperB HER & LER, CLIC DR (2009 and 2010 design parameters), SLC DR, and ATF DR. We show that the theoretical uncertainty in the instability onset is at least at the level of 20-30% in bunch intensity. More importantly, we present some doubts about the general applicability for many of these storage rings of some commonly used formulae. To cast further light on these questions, an experiment at lower beam energy on the ATF Damping Ring is proposed.

  12. Storage ring at HIE-ISOLDE Technical design report

    NARCIS (Netherlands)

    Grieser, M.; Litvinov, Yu. A.; Raabe, R.; Blaum, K.; Blumenfeld, Y.; Butler, P. A.; Wenander, F.; Woods, P. J.; Aliotta, M.; Andreyev, A.; Artemyev, A.; Atanasov, D.; Aumann, T.; Balabanski, D.; Barzakh, A.; Batist, L.; Bernardes, A. -P.; Bernhardt, D.; Billowes, J.; Bishop, S.; Borge, M.; Borzov, I.; Boston, A. J.; Brandau, C.; Catford, W.; Catherall, R.; Cederkall, J.; Cullen, D.; Davinson, T.; Dillmann, I.; Dimopoulou, C.; Dracoulis, G.; Duellmann, Ch. E.; Egelhof, P.; Estrade, A.; Fischer, D.; Flanagan, K.; Fraile, L.; Fraser, M. A.; Freeman, S. J.; Geissel, H.; Gerl, J.; Greenlees, P.; Grisenti, R. E.; Habs, D.; von Hahn, R.; Hagmann, S.; Hausmann, M.; He, J. J.; Heil, M.; Huyse, M.; Jenkins, D.; Jokinen, A.; Jonson, B.; Joss, D. T.; Kadi, Y.; Kalantar-Nayestanaki, N.; Kay, B. P.; Kiselev, O.; Kluge, H. -J.; Kowalska, M.; Kozhuharov, C.; Kreim, S.; Kroell, T.; Kurcewicz, J.; Labiche, M.; Lemmon, R. C.; Lestinsky, M.; Lotay, G.; Ma, X. W.; Marta, M.; Meng, J.; Muecher, D.; Mukha, I.; Mueller, A.; Murphy, A. St J.; Neyens, G.; Nilsson, T.; Nociforo, C.; Noertershaeuser, W.; Page, R. D.; Pasini, M.; Petridis, N.; Pietralla, N.; Pfuetzner, M.; Podolyak, Z.; Regan, P.; Reed, M. W.; Reifarth, R.; Reiter, P.; Repnow, R.; Riisager, K.; Rubio, B.; Sanjari, M. S.; Savin, D. W.; Scheidenberger, C.; Schippers, S.; Schneider, D.; Schuch, R.; Schwalm, D.; Schweikhard, L.; Shubina, D.; Siesling, E.; Simon, H.; Simpson, J.; Smith, J.; Sonnabend, K.; Steck, M.; Stora, T.; Stoehlker, T.; Sun, B.; Surzhykov, A.; Suzaki, F.; Tarasov, O.; Trotsenko, S.; Tu, X. L.; Van Duppen, P.; Volpe, C.; Voulot, D.; Walker, P. M.; Wildner, E.; Winckler, N.; Winters, D. F. A.; Wolf, A.; Xu, H. S.; Yakushev, A.; Yamaguchi, T.; Yuan, Y. J.; Zhang, Y. H.; Zuber, K.; Bosch, F.M.

    2012-01-01

    We propose to install a storage ring at an ISOL-type radioactive beam facility for the first time. Specifically, we intend to setup the heavy-ion, low-energy ring TSR at the HIE-ISOLDE facility in CERN, Geneva. Such a facility will provide a capability for experiments with stored secondary beams tha

  13. Damping Ring R&D at CESR-TA

    Energy Technology Data Exchange (ETDEWEB)

    Rubin, David L. [Cornell Univ., Ithaca, NY (United States). Dept. of Physics

    2015-01-23

    , and that an instability associated with residual gas in the beam pipe would limit the intensity of the electron ring. It was also not clear whether the required very small beam size could be achieved. The results of this study are important contributions to the design of both the electron and positron damping rings in which all of those challenges are addressed and overcome. Our findings are documented in the ILC Technical Design Report, a document that represents the work of an international collaboration of scientists. Our contributions include design of the beam magnetic optics for the 3 km circumference damping rings, the vacuum system and surface treatments for electron cloud mitigation, the design of the guide field magnets, design of the superconducting damping wigglers, and new detectors for precision measurement of beam properties. Our study informed the specification of the basic design parameters for the damping rings, including alignment tolerances, magnetic field errors, and instrumentation. We developed electron cloud modelling tools and simulations to aid in the interpretation of the measurements that we carried out in the Cornell Electron-positron Storage Ring (CESR). The simulations provide a means for systematic extrapolation of our measurements at CESR to the proposed ILC damping rings, and ultimately to specify how the beam pipes should be fabricated in order to minimize the effects of the electron cloud. With the conclusion of this study, the design of the essential components of the damping rings is complete, including the development and characterization (with computer simulations) of the beam optics, specification of techniques for minimizing beam size, design of damping ring instrumentation, R&D into electron cloud suppression methods, tests of long term durability of electron cloud coatings, and design of damping ring vacuum system components.

  14. Exact solutions for the spin tune for model storage rings

    CERN Document Server

    Mane, S R

    2002-01-01

    We present exact analytical expressions for the spin tune for arbitrary values of the orbital action for several storage ring models. The models we treat contain Siberian Snakes, the use of which is essential to preserve the polarization of beams in high-energy proton storage rings. Our solutions contain some novel features. We also prove a previously conjectured claim about the behavior of spin tuneshifts in rings with multiple Snakes. The conjecture is based on numerical simulations, but our proof is analytical, and also nonperturbative.

  15. Storage rings for investigation of ion-atom collisions

    Energy Technology Data Exchange (ETDEWEB)

    Schuch, R.

    1987-08-01

    In this survey, we give a brief description of synchrotron storage rings for heavy ions, and examples for their use in ion-atom collision physics. The compression of the phase space distribution of the ions by electron cooling, and the gain factors of in-ring experiments compared to single-pass experiments are explained. Some examples of a new generation of ion-atom collision experiments which may become feasible with storage rings are given. These include the studies of angular differential single- and double-electron capture cross sections, the production of slow highly charged recoil ions, and atomic collision processes using decelerated and crossed beam. 30 refs.

  16. Crystalline beams in dispersion-free storage rings

    Directory of Open Access Journals (Sweden)

    Masahiro Ikegami

    2006-12-01

    Full Text Available Generating a multidimensional crystalline beam in a storage ring has been known to be difficult without a special cooling force, i.e., tapered cooling, because of the momentum dispersion induced by bending magnets. It is, however, possible to eliminate the dispersion all around the ring by adding an electric dipole field in each magnetic bending region. A storage ring with such unique deflectors should enable us to reach multidimensional crystalline states with an ordinary untapered cooling force. In order to verify this expectation, molecular dynamics simulations are performed to study beam crystallization in several dispersion-free storage rings including the S-LSR at Kyoto University. The present results show that various crystalline states can be established without relying on the tapered force.

  17. First collision at renovated electron-positron accelerator

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    @@ On late afternoon July 19,2008,researchers at the CAS Institute of High Energy Physics (IHEP)in Beijing produced the first collisions in the upgraded Beijing Electron-Positron Collider (BEPCII).The feat was observed in the brand-new associated detector,Beijing Electron Spectrometer,III(BESIII).

  18. Alternative positron-target design for electron-positron colliders

    Energy Technology Data Exchange (ETDEWEB)

    Donahue, R.J. (Lawrence Berkeley Lab., CA (United States)); Nelson, W.R. (Stanford Linear Accelerator Center, Menlo Park, CA (United States))

    1991-04-01

    Current electron-positron linear colliders are limited in luminosity by the number of positrons which can be generated from targets presently used. This paper examines the possibility of using an alternate wire-target geometry for the production of positrons via an electron-induced electromagnetic cascade shower. 39 refs., 38 figs., 5 tabs.

  19. Three-photon annihilation of the electron-positron pairs

    OpenAIRE

    Frolov, A. M.

    2008-01-01

    Three-photon annihilation of the electron-positron pairs (= $(e^{-}, e^{+})-$pairs) is considered in the electron rest frame. The energy of the incident positron can be arbitrary. The analytical expression for the cross-section of three-photon annihilation of the $(e^{-},e^{+})-$pair has been derived and investigated.

  20. Interference fragmentation functions in electron-positron annihilation

    NARCIS (Netherlands)

    Boer, D; Jakob, R; Radici, M

    2003-01-01

    We study the process of electron-positron annihilation into back-to-back jets, where in each jet a pair of hadrons is detected. The orientation of these two pairs with respect to each other can be used to extract the interference fragmentation functions in a clean way: for instance, from BELLE or BA

  1. Design of a novel electrostatic ion storage ring at KACST

    CERN Document Server

    Ghazaly, M O A El; Welsch, C P; Alharbi, H H

    2013-01-01

    A new electrostatic storage ring for beams at energies up to 30keV.q is currently under development at the National Centre for Mathematics and Physics (NCMP), King Abdulaziz City for Science and Technology (KACST). The ring design is based on the existing electrostatic storage rings, but stretches significantly beyond them in that it shall form the core of a unique flexible experimental facility at KACST. The lattice of this ring has been designed in a way that enables the use of state-of-the-art experimental methods to study electron-ion, laser-ion, and ion-neutral beams interactions. The lattice design also allows for a future upgrade of the ring to a double storage ring structure that would enable ion-ion beam interactions to be performed. In this paper, we present the design of this ring with a focus on beam dynamics calculations for the 7o single-bend racetrack layout. The study is principally based on the SIMION8 program. We complemented this study further by using purpose-written routine and MAD-X simu...

  2. Simulation of Spin-orbit Dynamics in Storage Rings

    Science.gov (United States)

    Ivanov, A.; Andrianov, S.; Senichev, Yu.

    2016-09-01

    In the article a mapping approach based on nonlinear matrix integration for longterm spin-orbit dynamics simulation is briefly described. Using this technique the nonlinear effects of spin dynamics in an electrostatics storage ring are investigated. Namely, the fringe fields, the energy conservation law and the random field errors are considered. The necessity of examination of such effects arises, for example, in the storage ring design for search the Electrical Dipole Moment of proton and deuteron. The EDM ring is proposed to measure EDM using the spin transformation of polarized particle in the magneto-electrostatic elements of the ring. The article consists of short description of the spin-orbit simulation results based on the nonlinear model.

  3. SPARC Collaboration: New Strategy for Storage Ring Physics at FAIR

    CERN Document Server

    Stöhlker, Thomas; Bräuning-Demian, Angela; Lestinsky, Michael; Herfurth, Frank; Maier, Rudolf; Prasuhn, Dieter; Schuch, Reinhold; Steck, Markus

    2014-01-01

    SPARC collaboration at FAIR pursues the worldwide unique research program by utilizing storage ring and trapping facilities for highly-charged heavy ions. The main focus is laid on the exploration of the physics at strong, ultra-short electromagnetic fields including the fundamental interactions between electrons and heavy nuclei as well as on the experiments at the border between nuclear and atomic physics. Very recently SPARC worked out a realization scheme for experiments with highly-charged heavy-ions at relativistic energies in the High-Energy Storage Ring HESR and at very low-energies at the CRYRING coupled to the present ESR. Both facilities provide unprecedented physics opportunities already at the very early stage of FAIR operation. The installation of CRYRING, dedicated Low-energy Storage Ring (LSR) for FLAIR, may even enable a much earlier realisation of the physics program of FLAIR with slow anti-protons.

  4. Development of an Electron-Positron Source for Positron Annihilation Lifetime Spectroscopy

    Science.gov (United States)

    2009-12-19

    boosted frame where electric field reaches the Schwinger limit for production of electron-positron pairs from vacuum. The theoretical framework...were directed toward radiative shock hydrodynamics. Lowering the threshold for Schwinger electron-positron pair production (Stepan Bulanov

  5. Workshop on compact storage ring technology: applications to lithography

    Energy Technology Data Exchange (ETDEWEB)

    1986-05-30

    Project planning in the area of x-ray lithography is discussed. Three technologies that are emphasized are the light source, the lithographic technology, and masking technology. The needs of the semiconductor industry in the lithography area during the next decade are discussed, particularly as regards large scale production of high density dynamic random access memory devices. Storage ring parameters and an overall exposure tool for x-ray lithography are addressed. Competition in this area of technology from Germany and Japan is discussed briefly. The design of a storage ring is considered, including lattice design, magnets, and beam injection systems. (LEW)

  6. Quasi-isochronous storage ring for enhanced FEL performance

    Science.gov (United States)

    Ohgaki, H.; Robin, D.; Yamazaki, T.

    1996-02-01

    A compact storage ring is designed to be used as driver for a free electron laser (FEL). This ring can be operated very close to zero momentum compaction factor (α) to increase the electron density and thus the gain of the FEL. In order to control α with zero dispersion in the straight sections we use an inverted dipole located between the bending magnets and 4 families of quadrupoles. By using 3 families of sextupoles we can control the 2 transverse chromaticities and 2nd order momentum compaction. We find that the ring has sufficient dynamic aperture for good performance.

  7. Isochronicity Correction in the CR Storage Ring

    CERN Document Server

    Litvinov, S; Weick, H; Dolinskii, A

    2013-01-01

    A challenge for nuclear physics is to measure masses of exotic nuclei up to the limits of nuclear existence which are characterized by low production cross sections and short half-lives. The large acceptance Collector Ring (CR) at FAIR tuned in the isochronous ion-optical mode offers unique possibilities for measuring short-lived and very exotic nuclides. However, in a ring designed for maximal acceptance, many factors limit the resolution. One point is a limit in time resolution inversely proportional to the transverse emittance. But most of the time aberrations can be corrected and others become small for large number of turns. We show the relations of the time correction to the corresponding transverse focusing and that the main correction for large emittance corresponds directly to the chromaticity correction for transverse focusing of the beam. With the help of Monte-Carlo simulations for the full acceptance we demonstrate how to correct the revolution times so that in principle resolutions of dm/m=1E-6 ...

  8. Results from Electron-Positron Collisions at BESIII

    CERN Document Server

    Mitchell, R E

    2016-01-01

    A selection of results from electron-positron collisions at BESIII are reviewed. The results presented here illustrate the wide range of physics topics that can be studied using the Beijing Electron Positron Collider~(BEPC). At low collision energies, the cross section for $e^+e^-\\to \\pi^+\\pi^-$ provides much-needed input into theoretical calculations of the anomalous magnetic moment of the muon, and the reaction $e^+e^-\\to p\\bar{p}$ provides access to the electromagnetic form factors of the proton. In the charmonium region, a large sample of $\\psi^\\prime$ decays can be used to measure new decay modes of charmonium states. And at higher energies, BESIII is uniquely situated to explore questions concerning the still-unexplained $XYZ$ states.

  9. Magnetoacoustic solitons in dense astrophysical electron-positron-ion plasmas

    Science.gov (United States)

    Hussain, S.; Mahmood, S.; Mushtaq, A.

    2013-08-01

    Nonlinear magnetoacoustic waves in dense electron-positron-ion plasmas are investigated by using three fluid quantum magnetohydrodynamic model. The quantum mechanical effects of electrons and positrons are taken into account due to their Fermionic nature (to obey Fermi statistics) and quantum diffraction effects (Bohm diffusion term) in the model. The reductive perturbation method is employed to derive the Korteweg-de Vries (KdV) equation for low amplitude magnetoacoustic soliton in dense electron-positron-ion plasmas. It is found that positron concentration has significant impact on the phase velocity of magnetoacoustic wave and on the formation of single pulse nonlinear structure. The numerical results are also illustrated by taking into account the plasma parameters of the outside layers of white dwarfs and neutron stars/pulsars.

  10. Applying Frequency Map Analysis to the Australian Synchrotron Storage Ring

    CERN Document Server

    Tan, Yaw-Ren E; Le Blanc, Gregory Scott

    2005-01-01

    The technique of frequency map analysis has been applied to study the transverse dynamic aperture of the Australian Synchrotron Storage Ring. The results have been used to set the strengths of sextupoles to optimise the dynamic aperture. The effects of the allowed harmonics in the quadrupoles and dipole edge effects are discussed.

  11. Acceleration for the mu-Storage Ring Neutrino Source

    OpenAIRE

    Neuffer, David

    2000-01-01

    A muon storage ring neutrino source uses an induction linac for muon capture, a 200 MHz copper cavity system for cooling, and 200 and 400 MHz superconducting rf systems for acceleration to a final energy of up to 50 GeV. These systems and their requirements are discussed in this paper.

  12. Design studies for the electron storage ring EUTERPE

    Energy Technology Data Exchange (ETDEWEB)

    Xi Boling

    1995-05-18

    The 400 MeV electron storage ring EUTERPE is under construction at Eindhoven University of Technology. The ring is to be used as an experimental tool for accelerator physics studies and synchroton radiation applications. The main task of the current research work is the electron optical design of the ring. Lattice design is a basis for machine design as a whole. Design aspects regarding the basic lattice, based on single particle dynamics, include determination of the equilibrium beam size and bunch length, design of achromatic bending sections, selection of tune values, correction of chromaticity, and minimization of the natural emittance in the ring. The basic lattice designed for the EUTERPE ring has a high flexibility so that different electron optical modes can be realized easily. In low energy storage rings with a high beam current, collective effects can cause a significant change in the bunch length, the transverse emittance and the beam lifetime. In order to ensure a good optical performance for the ring, the choice of suitable parameters concerning the vacuum and RF system are essential as far as collective effects are concerned. An estimation of the collective effects in the ring is given. The injector for EUTERPE is a 75 MeV racetrack microtron which is injected from a 10 MeV linac. In order to get sufficient beam current in the ring, a special procedure of continuous injection with an adjustable locally shifted closed orbit has been presented. Details of the injection procedure and numerical simulations are given. (orig./HSI).

  13. Precision Measurements in Electron-Positron Annihilation: Theory and Experiment

    CERN Document Server

    Chetyrkin, Konstantin

    2016-01-01

    Theory results on precision measurements in electron-positron annihilation at low and high energies are collected. These cover pure QCD calculations as well as mixed electroweak and QCD results, involving light and heavy quarks. The impact of QCD corrections on the $W$-boson mass is discussed and, last not least, the status and the perspectives for the Higgs boson decay rate into $b\\bar b$, $c\\bar c$ and into two gluons.

  14. Anomalous Hollow Electron Beams in a Storage Ring

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Y.K.

    2005-04-12

    This paper reports the first observations of an anomalous hollow electron beam in the Duke storage ring. Created by exciting the single bunch beam in a lattice with a negative chromaticity, the hollow beam consists of a solid core inside and a large ring outside. We report the detailed measurements of the hollow beam phenomenon, including its distinct image pattern, spectrum signature, and its evolution with time. By capturing the post-instability bursting beam, the hollow beam is a unique model system for studying the transverse instabilities, in particular, the interplay of the wake field and the lattice nonlinearity. In addition, the hollow beam can be used as a powerful tool to study the linear and nonlinear particle dynamics in the storage ring.

  15. DESIGN OF VISIBLE DIAGNOSTIC BEAMLINE FOR NSLS2 STORAGE RING

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, W.; Fernandes, H.; Hseuh, H.; Kosciuk, B.; Krinsky, S.; Singh, O.

    2011-03-28

    A visible synchrotron light monitor (SLM) beam line has been designed at the NSLS2 storage ring, using the bending magnet radiation. A retractable thin absorber will be placed in front of the first mirror to block the central x-rays. The first mirror will reflect the visible light through a vacuum window. The light is guided by three 6-inch diameter mirrors into the experiment hutch. In this paper, we will describe design work on various optical components in the beamline. The ultra high brightness NSLS-II storage ring is under construction at Brookhaven National Laboratory. It will have 3GeV, 500mA electron beam circulating in the 792m ring, with very low emittance (0.9nm.rad horizontal and 8pm.rad vertical). The ring is composed of 30 DBA cells with 15 fold symmetry. Three damping wigglers will be installed in long straight sections 8, 18 and 28 to lower the emittance. While electrons pass through the bending magnet, synchrotron radiation will be generated covering a wide spectrum. There are other insertion devices in the storage ring which will generate shorter wavelength radiation as well. Synchrotron radiation has been widely used as diagnostic tool to measure the transverse and longitudinal profile. Three synchrotron light beam lines dedicated for diagnostics are under design and construction for the NSLS-II storage ring: two x-ray beam lines (pinhole and CRL) with the source points from Cell 22 BM{_}A (first bending in the DBA cell) and Cell22 three-pole wiggler; the third beam line is using visible part of radiation from Cell 30 BM{_}B (second bending magnet from the cell). Our paper focuses on the design of the visible beam line - SLM.

  16. Ion-Trapping Effect in UVSOR Storage Ring

    Science.gov (United States)

    Kasuga, Toshio; Yonehara, Hiroto; Kinoshita, Toshio; Hasumoto, Masami

    1985-09-01

    UVSOR is an electron-stage ring dedicated to vacuum ultraviolet synchrotron radiation research. The first beam was stored in the ring in November 1983, and from that time on, efforts have been devoted to improving the performance of the ring. Some inconvenient phenomena have been found during the accelerator studies. One of the most serious problems is the growth of the vertical size of the electron beam. This phenomenon is explained by the ion-trapping effect, in which the ions trapped in the electron beam change the operating point of the storage ring and enhance the coupling between horizontal and vertical oscillations, resulting in a considerable increase in the vertical beam size. This ion trapping was successfully cured by the RF knockout method, which excited the betatron oscillation.

  17. Performance of high-resolution position-sensitive detectors developed for storage-ring decay experiments

    Energy Technology Data Exchange (ETDEWEB)

    Yamaguchi, T., E-mail: yamaguti@phy.saitama-u.ac.jp [Department of Physics, Saitama University, Saitama 338-8570 (Japan); Suzaki, F. [Department of Physics, Saitama University, Saitama 338-8570 (Japan); Izumikawa, T. [RI Center, Niigata University, Niigata 951-8510 (Japan); Miyazawa, S. [Department of Physics, Saitama University, Saitama 338-8570 (Japan); Morimoto, K. [RIKEN Nishina Center, Wako, Saitama 351-0198 (Japan); Suzuki, T. [Department of Physics, Saitama University, Saitama 338-8570 (Japan); Tokanai, F. [Department of Physics, Yamagata University, Yamagata 990-8560 (Japan); Furuki, H.; Ichihashi, N.; Ichikawa, C. [Department of Physics, Saitama University, Saitama 338-8570 (Japan); Kitagawa, A. [National Institute of Radiological Sciences, Chiba 263-8555 (Japan); Kuboki, T. [Department of Physics, Saitama University, Saitama 338-8570 (Japan); Momota, S. [School of Environmental Science and Engineering, Kochi University of Technology, Kochi 782-8502 (Japan); Nagae, D. [Institute of Physics, University of Tsukuba, Ibaraki 305-8571 (Japan); Nagashima, M.; Nakamura, Y. [Department of Physics, Niigata University, Niigata 950-2181 (Japan); Nishikiori, R.; Niwa, T. [Institute of Physics, University of Tsukuba, Ibaraki 305-8571 (Japan); Ohtsubo, T. [Department of Physics, Niigata University, Niigata 950-2181 (Japan); Ozawa, A. [Institute of Physics, University of Tsukuba, Ibaraki 305-8571 (Japan); and others

    2013-12-15

    Highlights: • Position-sensitive detectors were developed for storage-ring decay spectroscopy. • Fiber scintillation and silicon strip detectors were tested with heavy ion beams. • A new fiber scintillation detector showed an excellent position resolution. • Position and energy detection by silicon strip detectors enable full identification. -- Abstract: As next generation spectroscopic tools, heavy-ion cooler storage rings will be a unique application of highly charged RI beam experiments. Decay spectroscopy of highly charged rare isotopes provides us important information relevant to the stellar conditions, such as for the s- and r-process nucleosynthesis. In-ring decay products of highly charged RI will be momentum-analyzed and reach a position-sensitive detector set-up located outside of the storage orbit. To realize such in-ring decay experiments, we have developed and tested two types of high-resolution position-sensitive detectors: silicon strips and scintillating fibers. The beam test experiments resulted in excellent position resolutions for both detectors, which will be available for future storage-ring experiments.

  18. Bunch length modulation in highly dispersive storage rings

    Directory of Open Access Journals (Sweden)

    C. Biscari

    2005-09-01

    Full Text Available Modulation of the bunch length in an electron storage ring appears with the combination of a high rf voltage derivative and large dispersion in the dipoles, producing drifting of the longitudinal phase plane along the closed orbit. The comparison is done between two different regimes: the one corresponding to high momentum compaction structures, in which the drifting in all dipoles has always the same direction, and the other one corresponding to low momentum compaction in which the drifting changes sign along the ring. Expressions for the longitudinal Twiss functions, energy spread and longitudinal emittance are given. The generalization to multiple rf systems is mentioned.

  19. Ion-Induced Beam Instability in an Electron Storage Ring

    Institute of Scientific and Technical Information of China (English)

    LI Yong-Jun; JIN Yu-Ming; LI Wei-Min; LIU Zu-Ping

    2000-01-01

    In a small electron storage ring, such as the Hefei Light Source (HLS) ring, the newly generated ions, which can not escape from the beam potential and then are trapped from turn to turn, will lead to the beam instability. The ions created by the leading bunches can perturb the trailing bunches and also themselves during their subsequent passage, which will make the amplitude of beam oscillation be damped and anti-damped periodically. A computer simulation based on the strong-weak model shows a good agreement with our analytical model using the linear theory.

  20. Synchronization of Chaotic Storage-Ring Free-Electron Laser by Bi-Directional Coupling Scheme with the Coupling Strength Varied Periodically

    Institute of Scientific and Technical Information of China (English)

    HUANG Liang-Yu; LUO Xiao-Shu

    2006-01-01

    @@ We analyse the chaotic dynamics of storage-ring free-electron lasers and report a bi-directional coupled scheme with the coupling strength varied periodically to synchronize two chaotic storage-ring free-electron lasers.

  1. The KACST Heavy-Ion Electrostatic Storage Ring

    Science.gov (United States)

    Almuqhim, A. A.; Alshammari, S. M.; El Ghazaly, M. O. A.; Papash, A. I.; Welsch, C. P.

    2011-10-01

    A novel Electrostatic Storage Ring (ESR) for beams at energies up to 30keV/q is now being constructed at the National Centre for Mathematics and Physics (NCMP), King Abdul-Aziz City for Science and Technology (KACST). The ring is designed to be the core of a highly flexible experimental platform that will combine a large package of complementary beam techniques for atomic and molecular physics and related fields. The lattice design had to cover the different experimental techniques that the ring will be equipped with, such as e.g. Electron-Ion, Laser-Ion, Ion-Ion or Ion-Neutral beams, in both crossed and merged-beam configurations. The development of such an ESR is realized in a staged approach, in which a simple and early-run adaptation of the ring is built first, and then this basic version is upgraded to a higher symmetry of the ultimate version of the ring. Here, we report a general overview of this technical development with a focus on the layout of the first built stage of the ring.

  2. Stabilization of betatron tune in Indus-2 storage ring

    Science.gov (United States)

    Saroj, Jena; Yadav, S.; K. Agrawal, R.; D. Ghodke, A.; Pravin, Fatnani; A. Puntambekar, T.

    2014-06-01

    Indus-2 is a synchrotron radiation source that is operational at RRCAT, Indore, India. It is essentially pertinent in any synchrotron radiation facility to store the electron beam without beam loss. During the day to day operation of Indus-2 storage ring, difficulty was being faced in accumulating higher beam current. After examination, it was found that the working point was shifting from its desired value during accumulation. For smooth beam accumulation, a fixed desired tune in both horizontal and vertical plane plays a significant role in avoiding beam loss via the resonance process. This required a betatron tune feedback system to be put in the storage ring. After putting ON this feedback, the beam accumulation was smooth. The details of this feedback and its working principle are described in this paper.

  3. Storage Ring Measurements of Electron Impact Ionization for Solar Physics

    Science.gov (United States)

    Hahn, Michael; Becker, A.; Bernhardt, D.; Grieser, M.; Krantz, C.; Lestinsky, M.; Müller, A.; Novotný, O.; Repnow, R.; Schippers, S.; Spruck, K.; Wolf, A.; Savin, D. W.

    2013-07-01

    The interpretation of astrophysical spectra requires knowledge of the charge state distribution (CSD) of the plasma. The CSD is determined by the rates of ionization and recombination. Thus, accurate electron impact ionization (EII) data are needed to calculate the CSD of the solar atmosphere as well as for other electron-ionized astrophysical objects, such as stars, supernovae, galaxies, and clusters of galaxies. We are studying EII for astrophysically important ions using the TSR storage ring located at the Max Plank Institute for Nuclear Physics in Heidelberg, Germany. Storage ring measurements are largely free of the metastable contamination found in other experimental geometries, resulting in unambiguous EII data. We have found discrepancies of about 10% - 30% between our measured cross sections and those commonly used in CSD models. Because it is impractical to perform experimental measurements for every astrophysically relevant ion, theory must provide the bulk of the necessary EII data. These experimental results provide an essential benchmark for such EII calculations.

  4. Normal conducting superbend in an ultralow emittance storage ring

    Directory of Open Access Journals (Sweden)

    F. Saeidi

    2015-08-01

    Full Text Available The Iranian Light Source Facility (ILSF is a new 3 GeV synchrotron radiation laboratory in the Middle East. As the main radiation source, the ILSF storage ring is based on a five-bend achromat lattice providing an ultralow horizontal beam emittance of 0.48 nm rad. In order to produce very bright high energy radiation from the bending magnet, a superbend electromagnet is designed to replace the central low-field dipole of the bare lattice. In this paper, we present some design features of the ILSF storage ring bending magnet radiation source and discuss the detailed physical and mechanical design of the normal conducting superbend electromagnet. The related beam dynamics issues have been investigated as well.

  5. Lattice study for the HLS-Ⅱ storage ring

    Institute of Scientific and Technical Information of China (English)

    BAI Zheng-He; WANG Lin; JIA Qi-Ka; LI Wei-Min

    2013-01-01

    The Hefei Light Source (HLS) is undergoing a major upgrade project,named HLS-Ⅱ,in order to obtain lower emittance and more insertion device straight sections.Undulators are the main insertion devices in the HLS-Ⅱstorage ring.In this paper,based on the database of lattice parameters built for the HLS-Ⅱ storage ring obtained by the global scan method,we use the quantity related to the undulator radiation brightness to more directly search for high brightness lattices.Lattice solutions for achromatic and non-achromatic modes are easily found with lower emittance,smaller beta functions at the center of the insertion device straight sections and lower dispersion in nonzero dispersion straight sections compared with the previous lattice solutions.In this paper,the superperiod lattice with alternating high and low horizontal beta functions in long straight sections for the achromatic mode is studied using the multiobjective particle swarm optimization algorithm.

  6. Feasibility of beam crystallization in a cooler storage ring

    Directory of Open Access Journals (Sweden)

    Yosuke Yuri

    2005-11-01

    Full Text Available It has been known theoretically that a charged-particle beam circulating in a storage ring exhibits an “ordered” configuration at the space-charge limit. Such an ultimate state of matter is called a crystalline beam whose emittance is ideally equal to zero except for quantum noise. This paper discusses how close one can come to various ordered states by employing currently available accelerator technologies. The dynamic nature of ultracold beams and conditions required for crystallization are briefly reviewed. Molecular dynamics simulations are performed to study the feasibility of this unique phenomenon, considering practical situations in general cooling experiments. It is pointed out that several essential obstacles must be overcome to reach a three-dimensional crystalline state in a storage ring. Doppler laser cooling of ion beams is also numerically simulated to explore the possibility of beam crystallization in an existing machine.

  7. Investigation of induced radioactivity in the CERN Large Electron Positron collider for its decommissioning

    CERN Document Server

    Silari, Marco

    2004-01-01

    The future installation of the Large Hadron Collider in the tunnel formerly housing the Large Electron Positron collider (LEP) required the dismantling of the latter after 11-year operation. As required by the French legislation, an extensive theoretical study was conducted before decommissioning to establish the possible activation paths both in the accelerator and in the four experiments (L3, ALEPH, OPAL and DELPHI) installed around the ring. The aim was to define which areas may contain activated material and which ones would be completely free of activation. The four major sources of activation in LEP, i.e., distributed and localized beam losses, synchrotron radiation and the super-conducting RF cavities, were investigated. Conversion coefficients from unit lost beam power to induced specific activity were established for a number of materials. A similar study was conducted for the four experiments, evaluating the four potential sources of induced radioactivity, namely e**+e **- annihilation events, two-p...

  8. A new method for beam stacking in storage rings

    Energy Technology Data Exchange (ETDEWEB)

    Bhat, C.M.; /Fermilab

    2008-06-01

    Recently, I developed a new beam stacking scheme for synchrotron storage rings called 'longitudinal phase-space coating' (LPSC). This scheme has been convincingly validated by multi-particle beam dynamics simulations and has been demonstrated with beam experiments at the Fermilab Recycler. Here, I present the results from both simulations and experiments. The beam stacking scheme presented here is the first of its kind.

  9. Physics of Superpulses in Storage Ring Free-Electron Lasers

    Directory of Open Access Journals (Sweden)

    Vladimir N. Litvinenko

    2008-01-01

    Full Text Available Contradictory to the widespread perception, storage ring free-electron lasers with substantial net gain can generate peak lasing power reaching GW levels in the so-called superpulse mode. This power level is sufficient for studies of nonlinear processes and efficient intracavity harmonic generation. This letter describes the physics of the superpulses and a phase-space refreshment in the electron beam responsible for this phenomenon.

  10. SR front ends of VEPP-4M storage ring

    CERN Document Server

    Fedotov, M G; Kuz'minykh, V S; Mironenko, L A; Mishnev, S I; Panchenko, V E; Protopopov, I Ya; Rachkova, V V; Rukhlyada, L P; Selivanov, A N

    2001-01-01

    The VEPP-4M storage ring system of SR front ends is described. SR is released by means of 14 front ends. Eleven of them are intended for beamlines of experimental stations. One front end is technical. For the permanent stabilization of an orbit of a beam with respect to a coordinate and angle in the vertical direction, two monitoring front ends are used. They take out SR from emission regions, which are at a large distance from one another.

  11. Bunch lengthening with bifurcation in electron storage rings

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Eun-San; Hirata, Kohji [National Lab. for High Energy Physics, Tsukuba, Ibaraki (Japan)

    1996-08-01

    The mapping which shows equilibrium particle distribution in synchrotron phase space for electron storage rings is discussed with respect to some localized constant wake function based on the Gaussian approximation. This mapping shows multi-periodic states as well as double bifurcation in dynamical states of the equilibrium bunch length. When moving around parameter space, the system shows a transition/bifurcation which is not always reversible. These results derived by mapping are confirmed by multiparticle tracking. (author)

  12. Application of Accelerators and Storage Rings: Accelerators in Medicine

    CERN Document Server

    Amaldi, U

    2013-01-01

    This document is part of Subvolume C 'Accelerators and Colliders' of Volume 21 'Elementary Particles' of Landolt-Börnstein - Group I 'Elementary Particles, Nuclei and Atoms'. It contains the the Section '11.3 Accelerators in Medicine' of the Chapter '11 Application of Accelerators and Storage Rings' with the content: 11.3 Accelerators in Medicine 11.3.1 Accelerators and Radiopharmaceuticals 11.3.2 Accelerators and Cancer Therapy

  13. Cooler storage ring accomplished at heavy ion facility in Lanzhou

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    @@ The Heavy Ion Research Facility in Lanzhou-Cooler Storage Ring (HIRFLCSR),a flagship facility of basic research in China,passed the acceptance check under auspices of the State Development and Reform Commission on 30 July in Lanzhou,capital of Gansu Province.The event was jointly presided over by the Commission's Vice Minister ZHANG Xiaoqian and CAS Executive Vice President BAI Chunli.

  14. Design of the Main Magnets of the SESAME Storage Ring

    CERN Document Server

    Milanese, A; Shehab, M

    2014-01-01

    This paper describes the magnetic design of the main magnets of the SESAME storage ring. The 16 dipoles are combined function bending magnets, designed with an adjustable iron shimming scheme. The 64 quadrupoles are of two different lengths and strengths. The 64 sextupoles are optimized for field quality in 3D without end pole chamfers and they include additional coils to provide a horizontal/vertical dipole and a skew quadrupole terms.

  15. General spin precession and betatron oscillation in storage rings

    Science.gov (United States)

    Fukuyama, Takeshi

    2016-07-01

    Spin precession of particles having both anomalous magnetic and electric dipole moments (EDMs) is considered. We give the generalized expression of spin precession of these particles injected with transversal extent in magnetic storage rings. This is the generalization of the Farley’s pitch correction [F. J. N. Farley, Phys. Lett. B 42, 66 (1972)], including radial oscillation as well as vertical one. The transversal betatron oscillation formulae of these particles are also reproduced.

  16. Scale Down Experiments for a Stellarator type Magnetostatic Storage Ring

    CERN Document Server

    Joshi, N; Meusel, O; Niebuhr, H; Ratzinger, U

    2016-01-01

    The beam transport experiments in toroidal magnets were first described in EPAC08 [1] within the framework of a proposed low energy ion storage ring at Frankfurt University. The experiments with two room temperature 30 degree toroids are needed to design the accumulator ring with closed longitudinal magnetic field levels up to 6-8 T. The test setup aims on developing a ring injection system. The primary beam line for the experiments was installed and successfully commissioned in 2009. A special probe for ion beam detection was installed. This modular technique allows online diagnostics of the ion beam along the beam path. In this paper, we present new results on beam transport experiments and discuss transport and transverse beam injection properties of that system.

  17. Internal target effects in ion storage rings with beam cooling

    Energy Technology Data Exchange (ETDEWEB)

    Gostishchev, Vitaly

    2008-06-15

    The accurate description of internal target effects is important for the prediction of operation conditions which are required for experiments in the planned storage rings of the FAIR facility. The BETACOOL code developed by the Dubna group has been used to evaluate beam dynamics in ion storage rings, where electron cooling in combination with an internal target is applied. Systematic benchmarking experiments of this code were carried out at the ESR storage ring at GSI. A mode with vanishing dispersion in the target position was applied to evaluate the influence of the dispersion function on the parameters when the target is heating the beam. The influence of the internal target on the beam parameters is demonstrated in the present work. A comparison of experimental results with simple models describing the energy loss of the beam particles in the target as well as with more sophisticated simulations with the BETACOOL code is given. In order to study the conditions which can be achieved in the proposed experiments the simulation results were quantitatively compared with experimental results and simulations for the ESR. The results of this comparison are discussed in the present thesis. BETACOOL simulations of target effects were performed for the NESR and the HESR of the future FAIR facility in order to predict the beam parameters for the planned experiments. (orig.)

  18. Thomson scattering off a pair (electron-positron) plasma

    Institute of Scientific and Technical Information of China (English)

    Zheng Jian

    2006-01-01

    Thomson scattering off a pair (electron-positron) plasma is theoretically investigated in the collisionless and collisional limits respectively. Our calculations show that the power spectrum of the Thomson scattering offa collisionless pair plasma is just proportional to the velocity distribution function of the particles in the plasma. Collective modes in the plasma do not have any effects on the Thomson scattering spectrum because of the correlation between the negatively- and positively-charged particles. In the collisional limit, the power spectrum of the Thomson scattering presents three spikes: two peaks correspond to two contra-propagating sound waves and one peak corresponds to an entropy wave.

  19. Compensation for booster leakage field in the Duke storage ring

    Science.gov (United States)

    Li, Wei; Hao, Hao; Mikhailov, Stepan F.; Popov, Victor; Li, Wei-Min; Wu, Ying. K.

    2017-01-01

    The High Intensity Gamma-ray Source (HIGS) at Duke University is an accelerator-driven Compton gamma-ray source, providing high flux gamma-ray beam from 1 MeV to 100 MeV for photo-nuclear physics research. The HIGS facility operates three accelerators, a linac pre-injector (0.16 GeV), a booster injector (0.16—1.2 GeV), and an electron storage ring (0.24—1.2 GeV). Because of the proximity of the booster injector to the storage ring, the magnetic field of the booster dipoles close to the ring can significantly alter the closed orbit in the storage ring being operated in the low energy region. This type of orbit distortion can be a problem for certain precision experiments which demand a high degree of energy consistency of the gamma-ray beam. This energy consistency can be achieved by maintaining consistent aiming of the gamma-ray beam, and therefore a steady electron beam orbit and angle at the Compton collision point. To overcome the booster leakage field problem, we have developed an orbit compensation scheme. This scheme is developed using two fast orbit correctors and implemented as a feedforward which is operated transparently together with the slow orbit feedback system. In this paper, we will describe the development of this leakage field compensation scheme, and report the measurement results, which demonstrate the effectiveness of the scheme. Supported by National Natural Science Foundation of China (11175180, 11475167) and US DOE (DE-FG02-97ER41033)

  20. DEPFET detectors for future electron-positron colliders

    Science.gov (United States)

    Marinas, C.

    2015-11-01

    The DEPFET Collaboration develops highly granular, ultra-thin pixel detectors for outstanding vertex reconstruction at future electron-positron collider experiments. A DEPFET sensor, by the integration of a field effect transistor on a fully depleted silicon bulk, provides simultaneous position sensitive detector capabilities and in pixel amplification. The characterization of the latest DEPFET prototypes has proven that a adequate signal-to-noise ratio and excellent single point resolution can be achieved for a sensor thickness of 50 micrometers. The close to final auxiliary ASICs have been produced and found to operate a DEPFET pixel detector of the latest generation with the required read-out speed. A complete detector concept is being developed for the Belle II experiment at the new Japanese super flavor factory. DEPFET is not only the technology of choice for the Belle II vertex detector, but also a prime candidate for the ILC. Therefore, in this contribution, the status of DEPFET R&D project is reviewed in the light of the requirements of the vertex detector at a future electron-positron collider.

  1. Future Synchrotron Light Sources Based on Ultimate Storage Rings

    Energy Technology Data Exchange (ETDEWEB)

    Cai, Yunhai; /SLAC

    2012-04-09

    The main purpose of this talk is to describe how far one might push the state of the art in storage ring design. The talk will start with an overview of the latest developments and advances in the design of synchrotron light sources based on the concept of an 'ultimate' storage ring. The review will establish how bright a ring based light source might be, where the frontier of technological challenges are, and what the limits of accelerator physics are. Emphasis will be given to possible improvements in accelerator design and developments in technology toward the goal of achieving an ultimate storage ring. An ultimate storage ring (USR), defined as an electron ring-based light source having an emittance in both transverse planes at the diffraction limit for the range of X-ray wavelengths of interest for a scientific community, would provide very high brightness photons having high transverse coherence that would extend the capabilities of X-ray imaging and probe techniques beyond today's performance. It would be a cost-effective, high-coherence 4th generation light source, competitive with one based on energy recovery linac (ERL) technology, serving a large number of users studying material, chemical, and biological sciences. Furthermore, because of the experience accumulated over many decades of ring operation, it would have the great advantage of stability and reliability. In this paper we consider the design of an USR having 10-pm-rad emittance. It is a tremendous challenge to design a storage ring having such an extremely low emittance, a factor of 100 smaller than those in existing light sources, especially such that it has adequate dynamic aperture and beam lifetime. In many ultra-low emittance designs, the injection acceptances are not large enough for accumulation of the electron beam, necessitating on-axis injection where stored electron bunches are completely replaced with newly injected ones. Recently, starting with the MAX-IV 7-bend

  2. Beam Loss Monitors for NSLS-II Storage Ring

    Energy Technology Data Exchange (ETDEWEB)

    Kramer, S.L.; Cameron, P.

    2011-03-28

    The shielding for the NSLS-II storage ring will provide adequate protection for the full injected beam losses in two cells of the ring around the injection point, but the remainder of the ring is shielded for lower losses of <10% top-off injection beam current. This will require a system to insure that beam losses do not exceed levels for a period of time that could cause excessive radiation exposure outside the shield walls. This beam Loss Control and Monitoring system will have beam loss monitors that will measure where the beam charge is lost around the ring, to warn operators if losses approach the design limits. To measure the charge loss quantitatively, we propose measuring the electron component of the shower as beam electrons hit the vacuum chamber (VC) wall. This will be done using the Cerenkov light as electrons transit ultra-pure fused silica rods placed close to the inner edge of the VC. The entire length of the rod will collect light from the electrons of the spread out shower resulting from the small glancing angle of the lost beam particles to the VC wall. The design and measurements results of the prototype Cerenkov BLM will be presented.

  3. Cooler Storage Ring at China Institute of Modern Physics

    CERN Document Server

    Wen-Xia, Jia; Zhan, W

    2005-01-01

    CSR, a new ion cooler-storage-ring project in China IMP, is a double ring system, and consists of a main ring (CSRm) and an experimental ring (CSRe). The two existing cyclotrons SFC (K=69) and SSC (K=450) of the Heavy Ion Research Facility in Lanzhou (HIRFL) will be used as its injector system. The heavy ion beams with the energy range of 7-30 MeV/nucleus from the HIRFL will be accumulated, cooled and accelerated to the higher energy range of 100-500 MeV/ nucleus in CSRm, and then extracted fast to produce radioactive ion beams or highly charged heavy ions. Those secondary beams will be accepted and stored or decelerated by CSRe for many internal-target experiments or high precision spectroscopy with beam cooling. On the other hand, the beams with the energy range of 100-1000MeV/ nucleus will also be extracted from CSRm by using slow extraction or fast extraction for many external-target experiments. CSR project was started in the end of 1999 and will be finished in 2006. In this paper the outline and the act...

  4. Ultra-low energy storage ring at FLAIR

    Energy Technology Data Exchange (ETDEWEB)

    Welsch, Carsten P., E-mail: c.p.welsch@liverpool.ac.uk [Cockcroft Institute and the University of Liverpool (United Kingdom); Papash, A. I.; Gorda, O. [Max Planck Institute for Nuclear Physics (Germany); Harasimowicz, J. [Cockcroft Institute and University of Liverpool (United Kingdom); Karamyshev, O.; Karamysheva, G. [Max Planck Institute for Nuclear Physics (Germany); Newton, D. [Cockcroft Institute and University of Liverpool (United Kingdom); Panniello, M. [Max Planck Institute for Nuclear Physics (Germany); Putignano, M.; Siggel-King, M. R. F. [Cockcroft Institute and University of Liverpool (United Kingdom); Smirnov, A. [Max Planck Institute for Nuclear Physics (Germany)

    2012-12-15

    The Ultra-low energy electrostatic Storage Ring (USR) at the future Facility for Low-energy Antiproton and Ion Research (FLAIR) will provide cooled beams of antiprotons in the energy range between 300 keV down to 20 keV and possibly less. The USR has been completely redesigned over the past three years. The ring structure is based on a 'split achromat' lattice that allows in-ring experiments with internal gas jet target. Beam parameters might be adjusted in a wide range: from very short pulses in the nanosecond regime to a Coasting beam. In addition, a combined fast and slow extraction scheme was developed that allows for providing external experiments with cooled beams of different time structure. Detailed investigations of the USR, including studies into the ring's long term beam dynamics, life time, equilibrium momentum spread and equilibrium lateral spread during collisions with an internal target were carried out. New tools and beam handling techniques for diagnostics of ultra-low energy ions at beam intensities less than 10{sup 6} were developed by the QUASAR Group. In this paper, progress on the USR project will be presented with an emphasis on the expected beam parameters available to the experiments at FLAIR.

  5. Fast cooling of bunches in compton storage rings*

    CERN Document Server

    Bulyak, E; Zimmermann, F

    2011-01-01

    We propose an enhancement of laser radiative cooling by utilizing laser pulses of small spatial and temporal dimensions, which interact only with a fraction of an electron bunch circulating in a storage ring. We studied the dynamics of such electron bunch when laser photons scatter off the electrons at a collision point placed in a section with nonzero dispersion. In this case of ‘asymmetric cooling’, the stationary energy spread is much smaller than under conditions of regular scattering where the laser spot size is larger than the electron beam; and the synchrotron oscillations are damped faster. Coherent oscillations of large amplitude may be damped within one synchrotron period, so that this method can support the rapid successive injection of many bunches in longitudinal phase space for stacking purposes. Results of extensive simulations are presented for the performance optimization of Compton gamma-ray sources and damping rings.

  6. Measurement of sextupole orbit offsets in the APS storage ring.

    Energy Technology Data Exchange (ETDEWEB)

    Borland, M.

    1999-04-16

    Horizontal orbit errors at the sextuples in the Advanced Photon Source (APS) storage ring can cause changes in tune and modulation of the beta functions around the ring. To determine the significance of these effects requires knowing the orbit relative to the magnetic center of the sextuples. The method considered here to determine the horizontal beam position in a given sextupole is to measure the tune shift caused by a change in the sextupole strength. The tune shift and a beta function for the same plane uniquely determine the horizontal beam position in the sextupole. The beta function at the sextupole was determined by propagating the beta functions measured at nearby quadrupoles to the sextupole location. This method was used to measure the sextupole magnetic center offset relative to an adjacent beam position monitor (BPM) at a number of sextupole locations. We report on the successes and problems of the method as well as an improved method.

  7. ELASR – An electrostatic storage ring for atomic and molecular physics at KACST

    Directory of Open Access Journals (Sweden)

    Mohamed O.A. El Ghazaly

    2015-01-01

    Full Text Available A new ELectrostAtic Storage Ring (ELASR has been designed and built at the King Abdulaziz City for Science and Technology (KACST, in Riyadh, Saudi Arabia. It was developed to be the core of a new storage ring laboratory for atomic and molecular physics at KACST. ELASR follows the standard design of the pioneering storage ring ELISA and it thereby features a racetrack single-bend shaped ring. Complementary simulation code packages were used to work out the design under the requirements of the projected experiments. This paper reports a short description of the ELASR storage ring through an overview of its design and construction.

  8. Radiation Damage of Polypropylene Fiber Targets in Storage Rings

    CERN Document Server

    Rohdjess, H; Bisplinghoff, J; Bollmann, R; Büsser, K; Diehl, O; Dohrmann, F; Engelhardt, H P; Eversheim, P D; Greiff, J; Gross, A; Gross-Hardt, R; Hinterberger, F; Igelbrink, M; Langkau, R; Maier, R; Mosel, F; Müller, M; Muenstermann, M; Prasuhn, D; Von Rossen, P; Scheid, H; Schirm, N; Schwandt, F; Scobel, W; Trelle, H J; Wellinghausen, A; Wiedmann, W; Woller, K; Ziegler, R

    2004-01-01

    Thin polypropylene (CH$_2$) fibers have been used for internal experiments in storage rings as an option for hydrogen targets. The change of the hydrogen content due to the radiation dose applied by the circulating proton beam has been investigated in the range $1\\cdot10^6$ to $2\\cdot10^8$~Gy at beam momenta of 1.5 to 3 GeV/c by comparing the elastic pp-scattering yield to that from inelastic p-carbon reactions. It is found that the loss of hydrogen as a function of applied dose receives contributions from a fast and a slow component.

  9. Design and manufacturing of the antechamber for BEPCII storage rings

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    Antechamber which composes the arc vacuum chamber of storage rings is one of the key devices of BEPCII. It has the characteristic of various specifications, large size, complex structure, and high dimension accuracy. This paper gives a review on the structure features and the procedure of production, including the mechanical machining process, cleaning and welding process of high vacuum aluminum alloy, ultrahigh vacuum test and so on. In view of the occurrence of the concave deformation, the reasons are analyzed and the correction method developed is introduced too.

  10. Beam loss studies at the ANKA storage ring

    Energy Technology Data Exchange (ETDEWEB)

    Hertle, Edmund; Smale, Nigel; Goetsch, Tobias; Mueller, Anke-Susanne; Wegh, Frans; Worms, Kai [Karlsruher Institut fuer Technologie (Germany)

    2013-07-01

    The real time study and the post mortem analysis of beam loss are powerful tools for the optimization of a storage ring's performance. It allows, for example, a fast identification of failing hardware components or can be used to improve the beam lifetime by a reduction of the losses. This needs a sophisticated beam loss monitor system with appropriate spatial and temporal resolution. This presentation gives an overview of the loss monitor system under study at the ANKA synchrotron radiation facility of the Karlsruhe Institute of Technology.

  11. Application of permanent magnets in accelerators and electron storage rings

    Science.gov (United States)

    Halbach, K.

    1985-04-01

    The use of permanent-magnet systems in high-energy accelerators and as sources of synchrotron radiation in electron-storage rings is discussed in a review of recent experimental investigations. Consideration is given to the generic advantages of permanent magnets over electromagnets (higher field strength per magnet size) in small-scale configurations; the magnetic properties of some charge-sheet-equivalent-permanent-magnet materials (CSEMs); and the design of pure-CSEM and CSEM-Fe-hybrid multipole magnetic lenses, dipoles, and undulator/wiggler systems for use in free-electron lasers and the production of elliptically polarized synchrotron light. Drawings and diagrams are provided.

  12. Study of orbit stability in the SSRF storage ring

    Institute of Scientific and Technical Information of China (English)

    DAI Zhi-Min; LIU Gui-Min; HUANG Nan

    2003-01-01

    In this paper, analysis of the beam orbit stability and conceptual study of the dynamic orbit feedback inthe SSRF storage ring are presented. It is shown that beam orbit position movement at the photon source points issmaller than the orbit stability requirements in horizontal plane, but exceeds the orbit stability requirements in verticalplane. A dynamic global orbit feedback system, which consists of 38 high-bandwidth air-coil correctors and 40high-precise BPMs, is proposed to suppress the vertical beam orbit position movement. Numerical simulations showthat this dynamic orbit feedback system can stabilize the vertical beam orbit position movement in the frequencyrange up to 100 Hz.

  13. The injection septum magnets of the SPring-8 storage ring

    Energy Technology Data Exchange (ETDEWEB)

    Kumagai, Keiko; Matsui, Sakuo [JAERI-RIKEN, Hyogo (Japan)

    1994-07-01

    Three DC septum magnets and a pulsed septum magnet are used for the injection of the SPring-8 storage ring. This paper describes the design principle of these injection septum magnets and the electromagnetic performances of a prototype pulsed magnet. The peak strength of the magnetic stray field of the pulsed septum magnet is 1.3 gauss on the bump orbit, and is lower than the limit of sensitivity of the measurement on the reference orbit when the field strength in the magnet gap is 5,600 gauss and the pulse width is 65 {mu}sec.

  14. Minimum emittance in storage rings with uniform or nonuniform dipoles

    Directory of Open Access Journals (Sweden)

    Chun-xi Wang

    2009-06-01

    Full Text Available A simple treatment of minimum emittance theory in storage rings is presented, favoring vector and matrix forms for a more concise picture. Both conventional uniform dipoles and nonuniform dipoles with bending radius variation are treated. Simple formulas are given for computing the minimum emittance, optimal lattice parameters, as well as effects of nonoptimal parameters. For nonuniform dipoles, analytical results are obtained for a three-piece sandwich dipole model. Minimization of the effective emittance for light sources is given in detail. Usefulness of gradient and/or nonuniform dipoles for reducing the effective emittance is addressed.

  15. Synchrobetatron resonant coupling mechanism in a storage ring

    Directory of Open Access Journals (Sweden)

    Kouichi Jimbo

    2016-01-01

    Full Text Available A clear synchrobetatron resonant coupling of Mg ion beam was observed experimentally in the horizontal laser beam cooling experiment in small laser equipped storage ring. Synchrotron and horizontal betatron motions were intentionally coupled in a rf cavity. Using the Hamiltonian which is composed of coasting, synchrotron and betatron motions, physical mechanism of the coupling is analyzed to explain the observed horizontal betatron tune jump near the synchrobetatron resonant coupling point. There energy exchange between the synchrotron oscillation and the horizontal betatron oscillation was mediated by coasting particles and the freedom of the horizontal direction is connected with the freedom of the longitudinal direction.

  16. Measurement of electric dipole moments at storage rings

    Science.gov (United States)

    Jörg Pretz JEDI Collaboration

    2015-11-01

    The electric dipole moment (EDM) is a fundamental property of a particle, like mass, charge and magnetic moment. What makes this property in particular interesting is the fact that a fundamental particle can only acquire an EDM via {P} and {T} violating processes. EDM measurements contribute to the understanding of the matter over anti-matter dominance in the universe, a question closely related to the violation of fundamental symmetries. Up to now measurements of EDMs have concentrated on neutral particles. Charged particle EDMs can be measured at storage ring. Plans at Forschungszentrum Jülich and results of first test measurements at the COoler SYnchrotron COSY will be presented.

  17. Gyrokinetic stability theory of electron-positron plasmas

    CERN Document Server

    Helander, Per

    2016-01-01

    The linear gyrokinetic stability properties of magnetically confined electron-positron plasmas are investigated in the parameter regime most likely to be relevant for the first laboratory experiments involving such plasmas, where the density is small enough that collisions can be ignored and the Debye length substantially exceeds the gyroradius. Although the plasma beta is very small, electromagnetic effects are retained, but magnetic compressibility can be neglected. The work of a previous publication (Helander, 2014) is thus extended to include electromagnetic instabilities, which are of importance in closed-field-line configurations, where such instabilities can occur at arbitrarily low pressure. It is found that gyrokinetic instabilities are completely absent if the magnetic field is homogeneous: any instability must involve magnetic curvature or shear. Furthermore, in dipole magnetic fields, the stability threshold for interchange modes with wavelengths exceeding the Debye radius coincides with that in i...

  18. Acoustic solitons in magnetized quantum electron-positron plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Mahmood, S; Akhtar, N; Ur-Rehman, H, E-mail: shahzadm100@gmail.com [Theoretical Plasma Physics Division (TPPD), PINSTECH, PO Nilore, Islamabad 44000 (Pakistan)

    2011-03-15

    Nonlinear acoustic wave propagation in dense magnetized electron-positron (e-p) plasmas in the presence of ions is studied. The e-p quantum fluid is taken to be dynamic, while the ions are assumed to be stationary to neutralize the plasma background only. The quantum hydrodynamics model is employed and the reductive perturbation method is used to derive the Zakharov-Kuznetsov equation. Electrostatic potential hump structures are obtained and it is found that an increase in positron concentration decreases the wave amplitude. However, an increase in magnetic field strength reduces the width of the structure significantly. The numerical results are also shown for illustration; the parameters used are taken from the data for the outer layers of white dwarfs.

  19. Spatially dependent electron-positron pair creation rate

    Science.gov (United States)

    Lv, Q. Z.; Unger, J.; Li, Y. T.; Su, Q.; Grobe, R.

    2016-11-01

    The vacuum breakdown process in an inhomogeneous supercritical electric field of finite extension is examined. By probing the electron-positron pair creation zone with incoming electrons that have controlled velocities, we can address the fundamental question of where the electrons are being created from the vacuum. In contrast to what one might expect, the spatial regions of most likely pair creation are not necessarily those where the electric-field strength is largest. In fact, the creation regions are determined solely by energetic considerations and particles can therefore be created in spatial regions where the local field strength is far below the Schwinger threshold. These predictions are also supported independently by spatial probability densities obtained by extrapolation as well as by classical and quantum-mechanical analysis.

  20. Nonlinear electromagnetic waves in a degenerate electron-positron plasma

    Energy Technology Data Exchange (ETDEWEB)

    El-Labany, S.K., E-mail: skellabany@hotmail.com [Department of Physics, Faculty of Science, Damietta University, New Damietta (Egypt); El-Taibany, W.F., E-mail: eltaibany@hotmail.com [Department of Physics, College of Science for Girls in Abha, King Khalid University, Abha (Saudi Arabia); El-Samahy, A.E.; Hafez, A.M.; Atteya, A., E-mail: ahmedsamahy@yahoo.com, E-mail: am.hafez@sci.alex.edu.eg, E-mail: ahmed_ateya2002@yahoo.com [Department of Physics, Faculty of Science, Alexandria University, Alexandria (Egypt)

    2015-08-15

    Using the reductive perturbation technique (RPT), the nonlinear propagation of magnetosonic solitary waves in an ultracold, degenerate (extremely dense) electron-positron (EP) plasma (containing ultracold, degenerate electron, and positron fluids) is investigated. The set of basic equations is reduced to a Korteweg-de Vries (KdV) equation for the lowest-order perturbed magnetic field and to a KdV type equation for the higher-order perturbed magnetic field. The solutions of these evolution equations are obtained. For better accuracy and searching on new features, the new solutions are analyzed numerically based on compact objects (white dwarf) parameters. It is found that including the higher-order corrections results as a reduction (increment) of the fast (slow) electromagnetic wave amplitude but the wave width is increased in both cases. The ranges where the RPT can describe adequately the total magnetic field including different conditions are discussed. (author)

  1. Higgs shifts from electron-positron annihilations near neutron stars

    Energy Technology Data Exchange (ETDEWEB)

    Wegner, Gary A. [Dartmouth College, Department of Physics and Astronomy, Hanover, NH (United States); Onofrio, Roberto [Universita di Padova, Dipartimento di Fisica e Astronomia ' Galileo Galilei' , Padova (Italy); ITAMP, Harvard-Smithsonian Center for Astrophysics, Cambridge, MA (United States)

    2015-07-15

    We discuss the potential for using neutron stars to determine bounds on the Higgs-Kretschmann coupling by looking at peculiar shifts in gamma-ray spectroscopic features. In particular, we reanalyze multiple lines observed in GRB781119 detected by two gamma-ray spectrometers, and derive an upper bound on the Higgs-Kretschmann coupling that is much more constraining than the one recently obtained from white dwarfs. This calls for targeted analyses of spectra of gamma-ray bursts from more recent observatories, dedicated searches for differential shifts on electron-positron and proton-antiproton annihilation spectra in proximity of compact sources, and signals of electron and proton cyclotron lines from the same neutron star. (orig.)

  2. Nonlinear Electromagnetic Waves in a Degenerate Electron-Positron Plasma

    Science.gov (United States)

    El-Labany, S. K.; El-Taibany, W. F.; El-Samahy, A. E.; Hafez, A. M.; Atteya, A.

    2015-08-01

    Using the reductive perturbation technique (RPT), the nonlinear propagation of magnetosonic solitary waves in an ultracold, degenerate (extremely dense) electron-positron (EP) plasma (containing ultracold, degenerate electron, and positron fluids) is investigated. The set of basic equations is reduced to a Korteweg-de Vries (KdV) equation for the lowest-order perturbed magnetic field and to a KdV type equation for the higher-order perturbed magnetic field. The solutions of these evolution equations are obtained. For better accuracy and searching on new features, the new solutions are analyzed numerically based on compact objects (white dwarf) parameters. It is found that including the higher-order corrections results as a reduction (increment) of the fast (slow) electromagnetic wave amplitude but the wave width is increased in both cases. The ranges where the RPT can describe adequately the total magnetic field including different conditions are discussed.

  3. Search for excited charged leptons in electron positron collisions

    CERN Document Server

    Vachon, Brigitte Marie Christine; Sobie, Randall

    2002-01-01

    A search for evidence that fundamental particles are made of smaller subconstituents is performed. The existence of excited states of fundamental particles would be an unambiguous indication of their composite nature. Experimental signatures compatible with the production of excited states of charged leptons in electron-positron collisions are studied. The data analysed were collected by the OPAL detector at the LEP collider. No evidence for the existence of excited states of charged leptons was found. Upper limits on the product of the cross-section and the electromagnetic branching fraction are inferred. Using results from the search for singly produced excited leptons, upper limits on the ratio of the excited lepton coupling constant to the compositeness scale are calculated. From pair production searches, 95% confidence level lower limits on the masses of excited electrons, muons and taus are determined to be 103.2 GeV.

  4. Beam based alignment of the SSRF storage ring

    Institute of Scientific and Technical Information of China (English)

    ZHANG Man-Zhou; LI Hao-Hu; JIANG Bo-Cheng; LIU Gui-Min; LI De-Ming

    2009-01-01

    There are 140 beam position monitors (BPMs) in the Shanghai Synchrotron Radiation Facility (SSRF) storage ring used for measuring the closed orbit. As the BPM pickup electrodes are assembled directly on the vacuum chamber, it is important to calibrate the electrical center offset of the BPM to an adjacent quadrupole magnetic center. A beam based alignment (BBA) method which varies individual quadrupole magnet strength and observes its effects on the orbit is used to measure the BPM offsets in both the horizontal and vertical planes. It is a completely automated technique with various data processing methods. There are several parameters such as the strength change of the correctors and the quadrupoles which should be chosen carefully in real measurement. After several rounds of BBA measurement and closed orbit correction, these offsets are set to an accuracy better than 10 μm. In this paper we present the method of beam based calibration of BPMs, the experimental results of the SSRF storage ring, and the error analysis.

  5. Octupole Focusing Relativistic Self-Magnetometer Electric Storage Ring "Bottle"

    CERN Document Server

    Talman, Richard

    2015-01-01

    A method proposed for measuring the electric dipole moment (EDM) of a charged fundamental particle such as the proton, is to measure the spin precession caused by a radial electric bend field $E_r$, acting on the EDMs of frozen spin polarized protons circulating in an all-electric storage ring. The dominant systematic error limiting such a measurement comes from spurious spin precession caused by unintentional and unknown average radial magnetic field $B_r$ acting on the (vastly larger) magnetic dipole moments (MDM) of the protons. Along with taking extreme magnetic shielding measures, the best protection against this systematic error is to use the storage ring itself, as a "self-magnetometer"; the exact magnetic field average $\\langle B_r\\rangle$ that produces systematic EDM error, is nulled to exquisite precision by orbit position control. By using octupole rather than quadrupole focusing the restoring force can be vanishingly small for small amplitude vertical betatron-like motion yet strong enough at larg...

  6. CESAR, 2 MeV electron storage ring.

    CERN Multimedia

    1967-01-01

    CESAR (CERN Electron Storage and Accumulation Ring) was built as a study-model for the ISR (Intersecting Storage Rings). The model had to be small (24 m circumference) and yet the particles had to be highly relativistic, which led to the choice of electrons. On the other hand, in order to model the behaviour of protons, effects from synchrotron radiation had to be negligible, which meant low magnetic fields (130 G in the bending magnets) and a corresponding low energy of 1.75 MeV. All the stacking (accumulation) procedures envisaged for the ISR were proven with CESAR, and critical aspects of transverse stability were explored. Very importantly, CESAR was the test-bed for the ultrahigh vacuum techniques and components, essential for the ISR, with a final pressure of 6E-11 Torr. The CESAR project was decided early in 1960, design was completed in 1961 and construction in 1963. After an experimental period from 1964 to 1967, CESAR was dismantled in 1968.

  7. CESAR, 2 MeV electron storage ring; general view.

    CERN Multimedia

    1964-01-01

    CESAR (CERN Electron Storage and Accumulation Ring) was built as a study-model for the ISR (Intersecting Storage Rings). The model had to be small (24 m circumference) and yet the particles had to be highly relativistic, which led to the choice of electrons. On the other hand, in order to model the behaviour of protons, effects from synchrotron radiation had to be negligible, which meant low magnetic fields (130 G in the bending magnets) and a corresponding low energy of 1.75 MeV. All the stacking (accumulation) procedures envisaged for the ISR were proven with CESAR, and critical aspects of transverse stability were explored. Very importantly, CESAR was the test-bed for the ultrahigh vacuum techniques and components, essential for the ISR, with a final pressure of 6E-11 Torr. The CESAR project was decided early in 1960, design was completed in 1961 and construction in 1963. After an experimental period from 1964 to 1967, CESAR was dismantled in 1968.

  8. STRIPLINE KICKER DESIGN FOR NSLS2 STORAGE RING

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, W.; Blednykh, A.; Krinsky, S.; Singh, O.

    2011-03-28

    In the NSLS2 storage ring, there are four stripline kickers/pickups. Two long striplines with electrode length of 30cm will be used as bunch-by-bunch transverse feedback actuators. Two short stripline kickers/pickups with 15cm length will mainly used for tune measurement excitation or signal pickup for the beam stability monitor. High shunt impedance of the long stripline kickers is demanded to produce 200 {micro}s damping time. Meanwhile the beam impedance should be minimized. The design work for these two types of stripline is discussed in this paper. NSLS2 is a third-generation light source under construction at Brookhaven National Laboratory. The machine will have < 1nm.rad horizontal emittance by using weak dipoles together with damping wigglers. For the storage ring of 792m circumference, geometric impedance, resistive wall impedance and ion effects are expected to be significant. A transverse bunch-by-bunch feedback system has been designed to suppress the coupled bunch instabilities. More information can be found in previous paper.

  9. Ion beam polarization in storage rings. Production, controlling and preservation

    Energy Technology Data Exchange (ETDEWEB)

    Prozorov, A. [St. Petersburg State Univ. (Russian Federation). V.A. Fock Research Institute for Physics; Labzowsky, L. [St. Petersburg State Univ. (Russian Federation). V.A. Fock Research Institute for Physics]|[St. Petersburg Nuclear Physics Institute (Russian Federation); Plunien, G. [Technische Univ. Dresden (Germany). Inst. fuer Theoretische Physik; Liesen, D. [Gesellschaft fuer Schwerionenforschung mbH, Darmstadt (Germany)]|[Heidelberg Univ. (Germany). Physikalisches Inst.; Bosch, F. [Gesellschaft fuer Schwerionenforschung mbH, Darmstadt (Germany); Fritzsche, S. [Gesellschaft fuer Schwerionenforschung mbH, Darmstadt (Germany)]|[Heidelberg Univ. (Germany). Physikalisches Inst.]|[Max-Planck Insitute of Nuclear Physics, Heidelberg (Germany); Surzhykov, A. [Max-Planck Insitute of Nuclear Physics, Heidelberg (Germany)

    2008-03-15

    The present paper reports on the actual status of the theoretical concepts for the production of polarized heavy ion beams in storage rings and for methods to control online the degree of polarization as well as investigations of the preservation of the polarization during the ion movement across the magnetic system of the ring. It is argued that for hydrogen-like ions beam polarization can be built up efficiently by optical pumping of the Zeeman sublevels of ground-state hyperfine levels and that the maximal achievable nuclear polarization exceeds 90%. Of special interest are polarized helium-like ions which can be produced by the capture of one electron, because in selected cases parity nonconservation effects are found to be of unprecedented size in Atomic Physics. The measurements of these effects require online-diagnostics of the degree of the ion beam polarization. It is shown that this can be accomplished by an online-detection of the linear polarization of the X-rays which are emitted with the capture of the electron. In order to investigate the preservation of the polarization of the ions stored in the ring, the concept of an instantaneous quantization axis is introduced. The dynamics of this axis and the behaviour of the polarization with respect to it are explored in detail. (orig.)

  10. Ion beam polarization in storage rings. Production, controlling and preservation

    Energy Technology Data Exchange (ETDEWEB)

    Prozorov, A. [St. Petersburg State Univ. (Russian Federation). V.A. Fock Research Institute for Physics; Labzowsky, L. [St. Petersburg State Univ. (Russian Federation). V.A. Fock Research Institute for Physics]|[St. Petersburg Nuclear Physics Institute (Russian Federation); Plunien, G. [Technische Univ. Dresden (Germany). Inst. fuer Theoretische Physik; Liesen, D. [Gesellschaft fuer Schwerionenforschung mbH, Darmstadt (Germany)]|[Heidelberg Univ. (Germany). Physikalisches Inst.; Bosch, F. [Gesellschaft fuer Schwerionenforschung mbH, Darmstadt (Germany); Fritzsche, S. [Gesellschaft fuer Schwerionenforschung mbH, Darmstadt (Germany)]|[Heidelberg Univ. (Germany). Physikalisches Inst.]|[Max-Planck Insitute of Nuclear Physics, Heidelberg (Germany); Surzhykov, A. [Max-Planck Insitute of Nuclear Physics, Heidelberg (Germany)

    2008-03-15

    The present paper reports on the actual status of the theoretical concepts for the production of polarized heavy ion beams in storage rings and for methods to control online the degree of polarization as well as investigations of the preservation of the polarization during the ion movement across the magnetic system of the ring. It is argued that for hydrogen-like ions beam polarization can be built up efficiently by optical pumping of the Zeeman sublevels of ground-state hyperfine levels and that the maximal achievable nuclear polarization exceeds 90%. Of special interest are polarized helium-like ions which can be produced by the capture of one electron, because in selected cases parity nonconservation effects are found to be of unprecedented size in Atomic Physics. The measurements of these effects require online-diagnostics of the degree of the ion beam polarization. It is shown that this can be accomplished by an online-detection of the linear polarization of the X-rays which are emitted with the capture of the electron. In order to investigate the preservation of the polarization of the ions stored in the ring, the concept of an instantaneous quantization axis is introduced. The dynamics of this axis and the behaviour of the polarization with respect to it are explored in detail. (orig.)

  11. Electromagnetic cascade in high energy electron, positron, and photon interactions with intense laser pulses

    CERN Document Server

    Bulanov, S S; Esarey, E; Leemans, W P

    2013-01-01

    The interaction of high energy electrons, positrons, and photons with intense laser pulses is studied in head-on collision geometry. It is shown that electrons and/or positrons undergo a cascade-type process involving multiple emissions of photons. These photons can consequently convert into electron-positron pairs. As a result charged particles quickly lose their energy developing an exponentially decaying energy distribution, which suppresses the emission of high energy photons, thus reducing the number of electron-positron pairs being generated. Therefore, this type of interaction suppresses the development of the electromagnetic avalanche-type discharge, i.e., the exponential growth of the number of electrons, positrons, and photons does not occur in the course of interaction. The suppression will occur when 3D effects can be neglected in the transverse particle orbits, i.e., for sufficiently broad laser pulses with intensities that are not too extreme. The final distributions of electrons, positrons, and...

  12. Status and upgrade of the VEPP-4 storage-ring facility

    Science.gov (United States)

    Levichev, E. B.

    2016-12-01

    The VEPP-4 facility is an e + e - collider with a beam energy up to 2 GeV. The scientific program includes topics in high-energy and nuclear physics, as well as various investigations using synchrotron radiation and polarized or unpolarized charged-particle beams. An energy upgrade to 5 GeV is planned, and reliable and efficient operation of the storage-ring complex upon increased energy must be provided. We discuss the recent experimental results and the opportunities to be created by the energy upgrade.

  13. Theoretical foundations of synchrotron and storage ring RF systems

    CERN Document Server

    Klingbeil, Harald; Lens, Dieter

    2015-01-01

    This course-tested text is an ideal starting point for engineers and physicists entering the field of particle accelerators. The fundamentals are comprehensively introduced, derivations of essential results are provided, and a consistent notation style used throughout the book allows readers to quickly familiarize themselves with the field, providing a solid theoretical basis for further studies.   Emphasis is placed on the essential features of the longitudinal motion of charged particle beams, together with the corresponding RF generation and power amplification devices for synchrotron and storage ring systems. In particular, electrical engineering aspects such as closed-loop control of system components are discussed.   The book also offers a valuable resource for graduate students in physics, electronics engineering, or mathematics looking for an introductory and self-contained text on accelerator physics.

  14. Spin Motion and Resonances in Accelerators and Storage Rings

    Energy Technology Data Exchange (ETDEWEB)

    Courant,E.

    2008-01-01

    Some of the basic aspects of the spin dynamics of accelerators and storage rings are reviewed. Since the components of spin parallel and perpendicular to the particle velocity behave differently it is desirable to reformulate the equations of spin motion in a frame of reference that exhibits this difference explicitly. The conventional treatment employs a coordinate system derived from a reference orbit. An alternate coordinate system, based on the actual trajectory of the particle, leads to simplified equations of spin motion but, contrary to a conjecture presented in a previous note, resonance strengths calculated by the conventional and the revised formalisms are identical, as pointed out by Kondratenko. Resonances induced by radiofrequency dipoles or solenoids are also treated; with rf dipoles it is essential to consider not only the direct effect of the dipole but also the contribution from oscillations induced by it.

  15. Ion trapping in the high-energy storage ring HESR

    Energy Technology Data Exchange (ETDEWEB)

    Hinterberger, Frank [Bonn Univ. (Germany). Helmholtz-Institut fuer Strahlen- und Kernphysik

    2011-10-15

    The problem of ion trapping in the high-energy storage ring HESR is studied in the present report. Positive ions are trapped in the negative potential well of the antiproton beam. The ions are produced by the interaction between the antiproton beam and the residual gas. The adverse effects of ion trapping like tune shifts, tune spreads and coherent instabilities are reviewed. The ion production rate by ionization of the residual gas molecules is estimated. The negative potential well and the corresponding electric fields of the antiproton beam are evaluated in order to study the transverse and longitudinal motion of the ions and the accumulation in trapping pockets. The removal of ions can be achieved using clearing electrodes and under certain conditions resonant transverse beam shaking. Diagnostic tools and measurements of trapped ion effects are sketched. (orig.)

  16. Coupling measurement and correction at the SSRF storage ring

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    Brightness is an important parameter for 3rd generation light source. Correcting the emittance coupling is a realistic way to increase brightness without any additional equipment in a machine under operation. The main sources of emittance coupling are betatron coupling and vertical dispersion. At the SSRF storage ring, tune split and LOCO are used to measure the respective betatron and emittance coupling. Both of these sources can be corrected by skew quadrupoles. By measuring the skew quadrupole-coupling response matrix, betatron coupling can be changed from 0.014% to 2%. But the vertical dispersion changes at the same time. LOCO can find the suitable setting to correct simultaneously the betatron coupling and vertical dispersion. The emittance coupling can be reduced to 0.17% by this method. More simulations show the potential for smaller emittance coupling if more skew quadrupoles are employed.

  17. Emittance growth induced by electron cloud in proton storage rings

    CERN Document Server

    Benedetto, Elena; Coppa, G

    2006-01-01

    In proton and positron storage rings with many closely spaced bunches, a large number of electrons can accumulate in the beam pipe due to various mechanisms (photoemission, residual gas ionization, beam-induced multipacting). The so-formed electron cloud interacts with the positively charged bunches, giving rise to instabilities, emittance growth and losses. This phenomenon has been observed in several existing machines such as the CERN Super Proton Synchrotron (SPS), whose operation has been constrained by the electron-cloud problem, and it is a concern for the Large Hadron Collider (LHC), under construction at CERN. The interaction between the beam and the electron cloud has features which cannot be fully taken into account by the conventional and known theories from accelerators and plasma physics. Computer simulations are indispensable for a proper prediction and understanding of the instability dynamics. The main feature which renders the beam-cloud interactions so peculiar is that the the electron cloud...

  18. Pulsed neutron fields measurements around a synchrotron storage ring

    Science.gov (United States)

    Caresana, Marco; Ballerini, Marcello; Ulfbeck, David Garf; Hertel, Niels; Manessi, Giacomo Paolo; Søgaard, Carsten

    2017-09-01

    A measurement campaign was performed for characterizing the neutron ambient dose equivalent, H*(10), in selected positions at ISA, Aarhus, Denmark, around the ASTRID and ASTRID2 storage rings. The neutron stray radiation field is characterized here by very intense radiation bursts with a low repetition rate, which result in a comparatively low average H*(10) rate. As a consequence, devices specifically conceived for operating in pulsed neutron fields must be employed for efficiently measuring in this radiation environment, in order to avoid severe underestimations of the H*(10) rate. The measurements were performed with the ELSE NUCLEAR LUPIN 5401 BF3-NP rem counter, a detector characterized by an innovative working principle that is not affected by dead time losses. This allowed characterizing both the H*(10) and the time structure of the radiation field in the pre-selected positions.

  19. Performance of the OK-4/Duke storage ring FEL

    CERN Document Server

    Litvinenko, V N; Pinayev, I V; Wu, Y

    2001-01-01

    In this paper, we report measured parameters of the OK-4 FEL driven by the Duke storage ring. The OK-4 FEL was being operated continuously for 2 yr in the broad wavelength range for user applications utilising spontaneous and coherent XUV and UV radiation as well as Compton back-scattered gamma-rays in the range of 2-58 MeV. During this time, the OK-4 FEL lased in the range from 193.7 to about 730 nm using five sets of mirrors and electron beam energies from 240 to 800 MeV. Our predictions for the OK-4 FEL are compared with measured performance, both in the CW and in the giant pulse mode. We discuss our future plans for the OK-4 FEL operation as well as the construction and commissioning of the OK-5 FEL with helical wigglers.

  20. Numerical simulation of crystalline ion beams in storage ring

    Science.gov (United States)

    Meshkov, I.; Möhl, D.; Katayama, T.; Sidorin, A.; Smirnov, A.; Syresin, E.; Trubnikov, G.; Tsutsui, H.

    2004-10-01

    The use of crystalline ion beams can increase luminosity in the collider and in experiments with targets for investigation of rare radioactive isotopes. The ordered state of circulating ion beams was observed at several storage rings: NAP-M (Proceedings of the Fourth All Union Conference on Charged Particle Accelerators, Vol. 2, Nauka, Moscow, 1975 (in Russian); Part. Accel. 7 (1976) 197; At. Energy 40 (1976) 49; Preprint CERN/PS/AA 79-41, Geneva, 1979) (Novosibirsk), ESR (Phys. Rev. Lett. 77 (1996) 3803) and SIS (Proceedings of EPAC'2000, 2000) (Darmstadt), CRYRING (Proceedings of PAC'2001, 2001) (Stockholm) and PALLAS (Proceedings of the Conference on Applications of Accelerators in Research and Industry, AIP Conference Proceedings, p. 576, in preparation) (München). New criteria of the beam orderliness are derived and verified with a new program code. Molecular dynamics technique is inserted in BETACOOL program (Proceedings of Beam Cooling and Related Topics, Bad Honnef, Germany, 2001) and used for numerical simulation of crystalline beams. The sudden reduction of momentum spread in the ESR experiment is described with this code. The simulation shows a good agreement with the experimental results. The code has then been used to calculate characteristics of the ordered state of ion beams for the MUSES Ion Ring (IR) (MUSES Conceptual Design Report, RIKEN, Japan, 2001) in collider mode. A new strategy of the cooling process is proposed which permits to increase significantly the linear density of the ordered ion beam and thereby the luminosity of electron-ion colliding experiments.

  1. EDM searches at storage rings with Wien filters

    Energy Technology Data Exchange (ETDEWEB)

    Saleev, Artem [Forschungszentrum Juelich GmbH (Germany). Inst. fuer Kernphysik; Nikolaev, Kolya [Landau Institute, Chernogolovka (Russian Federation); Collaboration: JEDI-Collaboration

    2013-07-01

    Future searches of an EDM of protons and deuterons at COSY storage ring in Juelich, envision the use of Wien filter acting as spin rotator. Crucial idea is that Wien filter produces spin kicks which give a growth of the EDM signal. In all approaches one starts with the injection of the vertically polarized beam. Radiofrequency Wien filter modulates spin tune of stored particles. If EDM is non-zero this modulation conspires with the EDM-induced rotation of the spin in the motional electric field in the ring and generates the EDM signal - the in-plane horizontal polarization. We discuss the duality between RF spin flipper and RF Wien filter and we argue why spin coherence time is equal for two devices. Another case is static Wien filter with constant fields. Behavior of spin vector is the same, but the machine is operated exactly at imperfection resonance (for protons, Gγ=2), which drastically decreases spin coherence time. Last case is more promising but it needs supercompensated magnetic lattice, an option which has to be studied further.

  2. Proceedings of the workshop on polarized targets in storage rings

    Energy Technology Data Exchange (ETDEWEB)

    Holt, R.J. (ed.)

    1984-08-01

    Polarization phenomena have played an increasingly important part in the study of nuclei and nucleons in recent years. Polarization studies have been hampered by the relatively few and rather fragile polarized targets which are presently available. The concept of polarized gas targets in storage rings opens a much wider range of possibilities than is available in the external target geometry. This novel method will represent a considerable advance in nuclear physics and will continue to receive much attention in plans for future facilities. An internal, polarized-target station is being planned for the cooler ring at the Indiana University Cyclotron Facility. Internal targets are compatible with recent designs of electron accelerators proposed by the Massachusetts Institute of Technology and the Southeastern Universities Research Association. The key to nuclear-science programs based on internal targets pivots on recent developments in polarized atomic beam methods, which include the more recent laser-driven polarized targets. The workshop drew together a unique group of physicists in the fields of high-energy, nuclear and atomic physics. The meeting was organized in a manner that stimulated discussion among the 58 participants and focused on developments in polarized target technology and the underlying atomic physics. An impressive array of future possibilities for polarized targets as well as current developments in polarized target technology were discussed at the workshop. Abstracts of individual items from the workshop were prepared separately for the data base.

  3. Ultimate storage ring based on fourth-order geometric achromats

    Directory of Open Access Journals (Sweden)

    Yunhai Cai

    2012-05-01

    Full Text Available We have designed an “ultimate” storage ring for a future light source that would be resided in the positron-electron-project (PEP tunnel and achieves the diffraction-limited emittances (at 1.5 Å of 12 pm-rad in both horizontal and vertical planes with a 4.5-GeV electron beam. These emittances include the contribution of intrabeam scattering at a nominal current of 200 mA in 3300 bunches. This quality beam in conjunction with a conventional 4-m undulator in a straight section can generate synchrotron radiation having a spectral brightness above 10^{22}  [photons/s/mm^{2}/mrad^{2}/0.1%BW] at a 10 keV photon energy. The high coherence at the diffraction limit makes this design competitive with 4th generation light sources based on an energy recovery linac. In addition, the beam lifetime is several hours and the dynamic aperture is large enough to allow off-axis injection. The alignment and stability tolerances, though challenging, are achievable. A ring with all these properties is only possible because of several major advances in mitigating the effects of nonlinear resonances.

  4. Towards laboratory produced relativistic electron-positron pair plasmas

    Science.gov (United States)

    Chen, Hui; Meyerhofer, D. D.; Wilks, S. C.; Cauble, R.; Dollar, F.; Falk, K.; Gregori, G.; Hazi, A.; Moses, E. I.; Murphy, C. D.; Myatt, J.; Park, J.; Seely, J.; Shepherd, R.; Spitkovsky, A.; Stoeckl, C.; Szabo, C. I.; Tommasini, R.; Zulick, C.; Beiersdorfer, P.

    2011-12-01

    We review recent experimental results on the path to producing electron-positron pair plasmas using lasers. Relativistic pair-plasmas and jets are believed to exist in many astrophysical objects and are often invoked to explain energetic phenomena related to Gamma Ray Bursts and Black Holes. On earth, positrons from radioactive isotopes or accelerators are used extensively at low energies (sub-MeV) in areas related to surface science positron emission tomography and basic antimatter science. Experimental platforms capable of producing the high-temperature pair-plasma and high-flux jets required to simulate astrophysical positron conditions have so far been absent. In the past few years, we performed extensive experiments generating positrons with intense lasers where we found that relativistic electron and positron jets are produced by irradiating a solid gold target with an intense picosecond laser pulse. The positron temperatures in directions parallel and transverse to the beam both exceeded 0.5 MeV, and the density of electrons and positrons in these jets are of order 10 16 cm -3 and 10 13 cm -3, respectively. With the increasing performance of high-energy ultra-short laser pulses, we expect that a high-density, up to 10 18 cm -3, relativistic pair-plasma is achievable, a novel regime of laboratory-produced hot dense matter.

  5. A Model of Electron-Positron Pair Formation

    Directory of Open Access Journals (Sweden)

    Lehnert B.

    2008-01-01

    Full Text Available The elementary electron-positron pair formation process is consideredin terms of a revised quantum electrodynamic theory, with specialattention to the conservation of energy, spin, and electric charge.The theory leads to a wave-packet photon model of narrow line widthand needle-radiation properties, not being available from conventionalquantum electrodynamics which is based on Maxwell's equations. Themodel appears to be consistent with the observed pair productionprocess, in which the created electron and positron form two raysthat start within a very small region and have original directionsalong the path of the incoming photon. Conservation of angular momentum requires the photon to possess a spin, as given by the present theory but not by the conventional one. The nonzero electric field divergence further gives rise to a local intrinsic electric charge density within the photon body, whereas there is a vanishing total charge of the latter. This may explain the observed fact that the photon decays on account of the impact from an external electric field. Such a behaviour should not become possible for a photon having zero local electric charge density.

  6. Timelike Virtual Compton Scattering from Electron-Positron Radiative Annihilation

    Energy Technology Data Exchange (ETDEWEB)

    Afanasev, Andrei; /Hampton U. /Jefferson Lab; Brodsky, Stanley J.; /SLAC; Carlson, Carl E.; /William-Mary Coll.; Mukherjee, Asmita; /Indian Inst. Tech., Mumbai

    2009-03-31

    We propose measurements of the deeply virtual Compton amplitude (DVCS) {gamma}* {yields} H{bar H}{gamma} in the timelike t = (p{sub H} + p{sub {bar H}}){sup 2} > 0 kinematic domain which is accessible at electron-positron colliders via the radiative annihilation process e{sup +}e{sup -} {yields} H{bar H}{gamma}. These processes allow the measurement of timelike deeply virtual Compton scattering for a variety of H{bar H} hadron pairs such as {pi}{sup +}{pi}{sup -}, K{sup +}K{sup -}, and D{bar D} as well as p{bar p}. As in the conventional spacelike DVCS, there are interfering coherent amplitudes contributing to the timelike processes involving C = - form factors. The interference between the amplitudes measures the phase of the C = + timelike DVCS amplitude relative to the phase of the timelike form factors and can be isolated by considering the forward-backward e{sup +} {leftrightarrow} e{sup -} asymmetry. The J = 0 fixed pole contribution which arises from the local coupling of the two photons to the quark current plays a special role. As an example we present a simple model.

  7. Timelike Virtual Compton Scattering from Electron-Positron Radiative Annihilation

    Energy Technology Data Exchange (ETDEWEB)

    Andrei Afanaciev,Andrei Afanasev, Stanley J. Brodsky, Carl E. Carlson, Asmita Mukherjee

    2010-02-01

    We propose measurements of the deeply virtual Compton amplitude (DVCS), gamma* to H H-bar gamma, in the timelike t = (p_{H} + p_{H-bar})^2 > 0 kinematic domain which is accessible at electron-positron colliders via the radiative annihilation process e+ e- to H H-bar gamma. These processes allow the measurement of timelike deeply virtual Compton scattering for a variety of H H-bar hadron pairs such as pi+ pi-, K+ K-, and D D-bar as well as p p-bar. As in the conventional spacelike DVCS, there are interfering coherent amplitudes contributing to the timelike processes involving C= - form factors. The interference between the amplitudes measures the phase of the C=+ timelike DVCS amplitude relative to the phase of the timelike form factors and can be isolated by considering the forward-backward e+ \\leftrightarrow e- asymmetry. The J=0 fixed pole contribution which arises from the local coupling of the two photons to the quark current plays a special role. As an example we present a simple model.

  8. New Results from Experiments at the HERA Storage Ring and from ARGUS

    Science.gov (United States)

    Wegener, D.

    1994-10-01

    Recent results from the ep storage ring HERA and from the e+e- storage ring DORIS II are discussed. Special emphasis is given to the specific layout of the detectors and to the progress in calorimetry achieved in the last few years. The impact of the ARGUS experiment on B- and π-physics is discussed.

  9. Analytical solutions for spin response functions in model storage rings with Siberian Snakes

    Energy Technology Data Exchange (ETDEWEB)

    Mane, S.R. [Convergent Computing Inc., P.O. Box 561, Shoreham, NY 11786 (United States)], E-mail: srmane@optonline.net

    2009-03-01

    I present analytical solutions for the spin response functions for radial field rf dipole spin flippers in models of storage rings with one Siberian Snake or two diametrically opposed orthogonal Siberian Snakes. The solutions can serve as benchmarks tests for computer programs. The spin response functions can be used to calculate the resonance strengths for radial field rf dipole spin flippers in storage rings.

  10. Coherent Harmonic Generation using the Elettra Storage-Ring Optical Klystron A Numerical Analysis

    CERN Document Server

    Curbis, F

    2005-01-01

    Coherent harmonic generation can be obtained by means of frequency up-conversion of a high-power external laser focused into the first undulator of an optical klystron. The standard configuration is based on a single-pass device, where the seed laser is synchronized with an electron beam entering the first undulator of the optical klystron after being accelerated using a linear accelerator. As an alternative, the optical klystron may be installed on a storage ring, where it is normally used as interaction region for an oscillator free-electron laser. In this case, removing the optical cavity and using an external seed, one obtains a configuration which is similar to the standard one but also presents some peculiar characteristics. In this paper we investigate the possibility of harmonic generation using the Elettra storage-ring optical klystron. We explore different experimental set-ups varying the beam energy, the seed characteristics and the strength of the optical-klystron dispersive section. We also study...

  11. Commissioning of the Cryogenic Plant for the Cryogenic Storage Ring (CSR) at Heidelberg

    CERN Document Server

    von Hahn, R; Grieser, M; Haberstroh, C; Kaiser, D; Lange, M; Laux, F; Menk, S; Orlov, D A; Repnow, R; Sieber, T; Quack, H; Varju, J; Wolf A

    2009-01-01

    At the Max-Planck-Institute for Nuclear Physics in Heidelberg a next generation electrostatic storage ring for low velocity atomic and molecular ion beams is under construction. In contrast to existing electrostatic storage rings, the Cryogenic Storage Ring CSR will be cooled down to temperatures below 2 K. Thus acting as a large cryopump it will provide long storage times and, in addition, open a new field of quantum state controlled molecular physics due to a low heat radiation background from space-like environment. A concept for cooling the storage ring has been developed and is presently tested by means of a linear trap as a prototype with a length of 1/10 of the planned ring. A commercial refrigerator with 21 W at 2 K has been successfully commissioned and was connected to the prototype. This paper presents the status of the cryogenic plant after the commissioning and one year of operation.

  12. Steady State Analysis of Short-wavelength, High-gainFELs in a Large Storage Ring

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Z.; Bane, K.; Cai, Y.; Chao, A.; Hettel, R.; /SLAC; Pellegrini, C.; /UCLA

    2007-10-15

    Storage ring FELs have operated successfully in the low-gain regime using optical cavities. Discussions of a high-gain FEL in a storage ring typically involve a special bypass to decouple the FEL interaction from the storage ring dynamics. In this paper, we investigate the coupled dynamics of a high-gain FEL in a large storage ring such as PEP and analyze the equilibrium solution. We show that an FEL in the EUV and soft x-ray regimes can be integrated into a very bright storage ring and potentially provides three orders of magnitude improvement in the average brightness at these radiation wavelengths. We also discuss possibilities of seeding with HHG sources to obtain ultra-short, high-peak power EUV and soft x-ray pulses.

  13. Resummed jet rates with heavy quarks in electron-positron collisions

    OpenAIRE

    Rodrigo, German; Krauss, Frank

    2003-01-01

    Expressions for Sudakov form factors for heavy quarks are presented. They are used to construct resummed jet rates in electron-positron annihilation. Predictions are given for production of bottom quarks at LEP and top quarks at the Linear Collider.

  14. QCD physics at hadron storage rings: From COSY to FAIR

    Indian Academy of Sciences (India)

    James Ritman

    2006-05-01

    As a result of the rapid rise of the coupling constant at low momentum transfers, perturbation theory is not an appropriate method to describe the strong interaction. In this kinematic regime other methods such as lattice QCD or effective field theories are more appropriate to investigate the appearance of a still unsettled phenomena: confinement and chiral symmetry breaking. Furthermore, the confinement of quarks and gluons to hadrons allows crucial tests of fundamental symmetries that are inherent to the QCD Lagrangian but are broken in hadronic systems. Thus, high precision measurements of the production and decay of specific hadronic states provides decisive benchmarks to investigate the properties of QCD in this regime. A new series of experiments are being prepared using nearly full acceptance detectors for neutral and charged particles around internal targets in high intensity, phase-space-cooled hadronic beams. Later this year, it is planned to transfer the WASA detector from the CELSIUS to the COSY ring in order to measure the production and various decay channels of the and ' mesons, thereby investigating the violation of P, C, T, and combinations thereof, as well as isospin violation. The experimental and theoretical techniques employed here will provide an important basis to extend these investigations to the static and dynamical properties of hadrons with charm quark content with the high energy storage ring for antiprotons at the new GSI/FAIR facility. Additional related perspectives will be opened at the new facility ranging from the properties of hadrons in dense nuclear matter to measurements of the nucleon's transverse spin distribution in the valence quark region using polarized antiprotons.

  15. Wakefields generated by collisional neutrinos in neutral-electron-positron-ion plasma

    Energy Technology Data Exchange (ETDEWEB)

    Tinakiche, Nouara [Faculty of Sciences, Department of Physics, University of Boumeredes U.M.B.B., Boumerdes 35000 (Algeria)

    2015-12-15

    A classical fluid description is adopted to investigate nonlinear interaction between an electron-type neutrino beam and a relativistic collisionless unmagnetized neutral-electron-positron-ion plasma. In this work, we consider the collisions of the neutrinos with neutrals in the plasma and study their effect on the generation of wakefields in presence of a fraction of ions in a neutral-electron-positron plasma. The results obtained in the present work are interpreted and compared with previous studies.

  16. Two-site Hubbard molecule with a spinless electron-positron pair

    KAUST Repository

    Cossu, Fabrizio

    2012-12-19

    We determine the eigenvalues of the two-site Hubbard molecule with one electron and one positron to describe the characteristics of electron-positron interactions in solids. While the effect of hopping is, in general, opposite to the effect of on-site interaction, we find a complex scenario for the electron-positron pair with a non-vanishing potential drop. We give analytical solutions and discuss the combined effects of the model parameters.

  17. The electrostatic Cryogenic Storage Ring CSR - Mechanical concept and realization

    Science.gov (United States)

    von Hahn, R.; Berg, F.; Blaum, K.; Crespo Lopez-Urrutia, J. R.; Fellenberger, F.; Froese, M.; Grieser, M.; Krantz, C.; Kühnel, K.-U.; Lange, M.; Menk, S.; Laux, F.; Orlov, D. A.; Repnow, R.; Schröter, C. D.; Shornikov, A.; Sieber, T.; Ullrich, J.; Wolf, A.; Rappaport, M.; Zajfman, D.

    2011-12-01

    A new and technologically challenging project, the electrostatic Cryogenic Storage Ring CSR, is presently under construction at the Max-Planck-Institute for Nuclear Physics in Heidelberg. Applying liquid helium cooling, the CSR, with 35 m circumference, will provide a low temperature environment of only a few Kelvin and an extremely high vacuum of better than 10 -13 mbar. To realize these conditions the mechanical design has been completed and now the first quarter section is in the construction phase. For the onion skin structure of the cryogenic system we have at the outer shell the cryostat chambers, realized by welded rectangular stainless steel frames with aluminum plates. The next two shells are fabricated as aluminum shields kept at 80 and 40 K. The inner vacuum chambers for the experimental vacuum consist of stainless steel chambers cladded with external copper sheets connected to the LHe lines for optimized thermal equilibration and cryopumping. Additional large surface 2 K units are installed for cryogenic pumping of H 2. The mechanical concepts and the realization will be presented in detail.

  18. Design of the muon collider isochronous storage ring lattice

    Science.gov (United States)

    Trbojevic, D.; Ng, K. Y.; Courant, E. D.; Lee, S. Y.; Johnstone, C.; Gallardo, J.; Palmer, R.; Tepikian, S.

    1996-04-01

    The muon collider would extend the limitations of e+ e- colliders and provide new physics potentials, with possible discovery of the heavy Higgs bosons. At the maximum energy of 2 TeV the projected luminosity is of the order of 1035 cm-2 s-1. The colliding μ+ μ- bunches have to be focused to a very small transverse size of 2.8 μm, which is accomplished by the betatron functions at the crossing point of β*=3 mm. This requires a longitudinal space of the same length, 3 mm. These very short bunches at 2 TeV could circulate only in a quasi-isochronous storage ring where the momentum compaction is very close to zero. We report on a design of a muon collider isochronous lattice. The momentum compaction is brought to zero by having the average value of the dispersion function through dipoles equal to zero. This is accomplished by a combination of FODO cells with a low-beta insertion. The dispersion function oscillates between negative and positive values.

  19. Historic moment as SESAME begins storage ring installation

    CERN Multimedia

    JORDAN

    2016-01-01

    The first of the 16 cells of SESAME (link is external)’s storage ring was installed recently in the shielding tunnel in the Centre’s experimental hall in Allan, Jordan. SESAME will be the Middle East’s first synchrotron light source. The installation was led by SESAME’s Technical Director, Erhard Huttel, with help from members of CERN forming part of the CESSAMag (CERN-EC Support for SESAME Magnets) team as well as scientists and technicians from the SESAME region. Each cell consists of magnets (dipole, quadrupoles and sextupoles) and the vacuum chamber, supported by a girder. After many years in the making, commissioning of SESAME is scheduled to begin in 2016, serving a growing community of some 300 scientists from the region. The initial research programme will cover topics as diverse as the search for new cancer drugs to the exploration of the regions shared cultural heritage. SESAME is also a pioneer in promoting international cooperation in the region. The laboratory is expected

  20. Effects of insertion device on SSRF storage ring

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Shanghai Synchrotron Radiation Facility (SSRF), one of the third generation light sources, aims to produce high brightness and/or high flux X-ray source for users; therefore insertion devices (IDs) are important magnetic elements for SSRF. In this paper, the linear perturbations due to IDs toward its storage ring lattice, such as beta function distortions, tune shifts, emittance growths, and energy spreads are estimated by using analytical formulae, and the nonlinear effects from IDs, especially dynamic aperture, are simulated by using Racetrack code. The results show that (a) the reduction of dynamic aperture from single undulator is negligible, since electron beam energy of 3.5 GeV is high and ID's magnetic field is low, and the beta functions in the middle of straight sections, where ID is located, are well optimized; (b) however, the reduction from single wigglers, especially super-conducting wiggler, is visible, because of its higher magnetic field; (c) effects of each ID on emittance growths and energy spreads are less than 7%.

  1. Long-term stability of the APS storage ring

    Energy Technology Data Exchange (ETDEWEB)

    Friedsam, H.; Penicka, M.; Error, J.

    1999-10-26

    The Advanced Photon Source (APS), a third-generation synchrotrons light source, was commissioned in 1995 at Argonne ''National Laboratory and has been fully-operational for beamline users since 1997. The APS storage ring can accommodate up to 68 user beamlines; about 70% of the available beamlines are currently in use by various collaborative access teams (CATS). The 7-GeV synchrotrons light source produces light in the soft to hard x-ray range that is used for research in such areas as x-ray instrumentation; material, chemical and atomic sciences; biology; and geo/soil/ environmental sciences. For the successful operation of an x-ray light source such as the Advanced Photon Source, the long-term stability of the concrete floor supporting the beam components and user beamlines is crucial. Settlements impact the orbit and location of the x-ray source points as well as the position of the x-ray beamlines. This paper compares the results of two successive resurveys of the APS accelerator components performed in 1995 and 1998.

  2. Resonant beam behavior studies in the Proton Storage Ring

    Directory of Open Access Journals (Sweden)

    S. Cousineau

    2003-07-01

    Full Text Available We present studies of space-charge-induced beam profile broadening at high intensities in the Proton Storage Ring (PSR at Los Alamos National Laboratory. We investigate the profile broadening through detailed particle-in-cell simulations of several experiments and obtain results in good agreement with the measurements. We interpret these results within the framework of coherent resonance theory. With increasing intensity, our simulations show strong evidence for the presence of a quadrupole-mode resonance of the beam envelope with the lattice in the vertical plane. Specifically, we observe incoherent tunes crossing integer values, and large amplitude, nearly periodic envelope oscillations. At the highest operating intensities, we observe a continuing relaxation of the beam through space charge forces leading to emittance growth. The increase of emittance commences when the beam parameters encounter an envelope stop band. Once the stop band is reached, the emittance growth balances the intensity increase to maintain the beam near the stop band edge. Additionally, we investigate the potential benefit of a stop band correction to the high intensity PSR beam.

  3. Storage ring lattice calibration using resonant spin depolarization

    Directory of Open Access Journals (Sweden)

    K. P. Wootton

    2013-07-01

    Full Text Available This paper presents measurements of the GeV-scale electron beam energy for the storage rings at the synchrotron light source facilities Australian Synchrotron (AS and SPEAR3 at SLAC. Resonant spin depolarization was employed in the beam energy measurement, since it is presently the highest precision technique and an uncertainty of order 10^{-6} was achieved at SPEAR3 and AS. Using the resonant depolarization technique, the beam energy was measured at various rf frequencies to measure the linear momentum compaction factor. This measured linear momentum compaction factor was used to evaluate models of the beam trajectory through combined-function bending magnets. The main bending magnets of both lattices are rectangular, horizontally defocusing gradient bending magnets. Four modeling approaches are compared for the beam trajectory through the bending magnet: a circular trajectory, linear and nonlinear hyperbolic cosine trajectories, and numerical evaluation of the trajectory through the measured magnetic field map. Within the uncertainty of the measurement the momentum compaction factor is shown to agree with the numerical model of the trajectory within the bending magnet, and disagree with the hyperbolic cosine approximation.

  4. Initial scientific uses of coherent synchrotron radiation inelectron storage rings

    Energy Technology Data Exchange (ETDEWEB)

    Basov, D.N.; Feikes, J.; Fried, D.; Holldack, K.; Hubers, H.W.; Kuske, P.; Martin, M.C.; Pavlov, S.G.; Schade, U.; Singley, E.J.; Wustefeld, G.

    2004-11-23

    The production of stable, high power, coherent synchrotron radiation at sub-terahertz frequency at the electron storage ring BESSY opens a new region in the electromagnetic spectrum to explore physical properties of materials. Just as conventional synchrotron radiation has been a boon to x-ray science, coherent synchrotron radiation may lead to many new innovations and discoveries in THz physics. With this new accelerator-based radiation source we have been able to extend traditional infrared measurements down into the experimentally poorly accessible sub-THz frequency range. The feasibility of using the coherent synchrotron radiation in scientific applications was demonstrated in a series of experiments: We investigated shallow single acceptor transitions in stressed and unstressed Ge:Ga by means of photoconductance measurements below 1 THz. We have directly measured the Josephson plasma resonance in optimally doped Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8} for the first time and finally we succeeded to confine the sub-THz radiation for spectral near-field imaging on biological samples such as leaves and human teeth.

  5. Planning and Prototyping for a Storage Ring Measurement of the Proton Electric Dipole Moment

    Energy Technology Data Exchange (ETDEWEB)

    Talman, Richard [Cornell Univ., Ithaca, NY (United States)

    2015-07-01

    Electron and proton EDM's can be measured in "frozen spin" (with the beam polarization always parallel to the orbit, for example) storage rings. For electrons the "magic" kinetic energy at which the beam can be frozen is 14.5 MeV. For protons the magic kinetic energy is 230 MeV. The currently measured upper limit for the electron EDM is much smaller than the proton EDM upper limit, which is very poorly known. Nevertheless, because the storage ring will be an order of magnitude cheaper, a sensible plan is to first build an all-electric electron storage ring as a prototype. Such an electron ring was successfully built at Brookhaven, in 1954, as a prototype for their AGS ring. This leaves little uncertainty concerning the cost and performance of such a ring. (This is documentedin one of the Physical Review papers mentioned above.)

  6. Cabling design of booster and storage ring construction progress of TPS

    Science.gov (United States)

    Wong, Y.-S.; Liu, K.-B.; Liu, C.-Y.; Wang, b.-S.

    2017-06-01

    The 2012 Taiwan Photon Source (TPS) cable construction project started after 10 months to complete the cable laying and installation of power supply. The circumference of the booster ring (BR) is 496.8 m, whereas that of the storage ring (SR) is 518.4 m. Beam current is set to 500 mA at 3.3 GeV. The paper on grounding systems discusses the design of the ground wire (bending dipole; the cable size of its stranded wire measures 250 mm2, with a total length of 5000 m. Booster ring and storage ring quadrupoles have 150 magnets; the cable size of their stranded wire is 250 mm2, with a total length of 17000 m. Storage ring dipole consists of 48 magnets; the cable size of its stranded wire is 325 mm2, with a total length of 6000 m. This study discusses the power supply cabling design of the storage ring and booster ring construction progress of TPS. The sections of this paper are divided into discussions of the construction of the control and instrument area, cabling layout of booster ring and storage ring, as well as the installation and commission machine. This study also discusses the use of a high-impedance meter to determine the effect of cabling insulation and TPS power supply machine on energy transfer to ensure the use of safe and correct magnet.

  7. The Potential of an Ultimate Storage Ring for Future Light Sources

    Science.gov (United States)

    Bei, M.; Borland, M.; Cai, Y.; Elleaume, P.; Gerig, R.; Harkay, K.; Emery, L.; Hutton, A.; Hettel, R.; Nagaoka, R.; Robin, D.; Steier, C.

    2010-10-01

    This paper is the report of the working group on Ultimate Storage Rings at the Department of Energy's Basic Energy Sciences Workshop on Physics of Future Light Sources, which took place in Gaithersburg, Maryland on September 15-17, 2009. In this report we address the accelerator design issues related to the next generation of storage ring light sources, deemed "ultimate" storage rings. In our estimation, storage rings have the potential to provide an increase in photon brightness and coherent flux that is two orders of magnitude above that projected for rings currently under construction. In addition to photon brightness and coherent flux, we discuss other directions, such as shorter pulses, tailored bunches, and partial lasing, in which rings could evolve. For the most part we envision ultimate storage rings as an evolutionary advance from existing rings that faces no fundamental technological obstacles. Nevertheless we identify several important areas of R&D that should be pursued to enable the realization of the full potential of ultimate ring light sources.

  8. Storage-ring ionization and recombination experiments with multiply charged ions relevant to astrophysical and fusion plasmas

    CERN Document Server

    Schippers, Stefan

    2011-01-01

    Past and ongoing research activities at the Heidelberg heavy-ion storage-ring TSR are reviewed which aim at providing accurate absolute rate coefficients and cross sections of atomic collision processes for applications in astrophysics and magnetically confined fusion. In particular, dielectronic recombination and electron impact ionization of iron ions are discussed as well as dielectronic recombination of tungsten ions.

  9. Users program for storage-ring based FEL and synchrotron sources of the Duke FEL Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Straub, K.D.; Barnett, G.; Burnham, B. [and others

    1995-12-31

    The storage ring at the Duke FEL Laboratory was first operated with a stored e-beam in November, 1994. It has now achieved operation energies in excess 1 GeV with more than 100 mA current at 280 MeV. The ring has several ports for FEL and synchrotron light source research. The circulating ring current can be synchronized with the seperate Mark III FEL operating in the 2-9.5 {mu}m IR region. This allows low optical jitter (10-20 ps) between the two sources and thus pump-probe operation. The ring has been configured to drive a number of light sources including the OK-4 FEL system capable of FEL operation between 400 and 65 nm, an inverse Compton scattering source using this undulator which will yield 4-200 MeV gammas, an undulator source at approximately 40 {angstrom} (not an FEL), a mm FEL with inverse compton scattering providing 1-100 keV x-rays and two synchrotron ports from the bend magnets for which the {lambda}{sub c} = 11-12 {angstrom} for 1 GeV. The broadly tunable FEL sources and their associated inverse compton scattering are extremely bright. The initial research proposals, submitted to the Laboratory emphasizes photoelectron spectroscopy, PEEM, high resolution vacuum UV of gases, solid spectroscopy and photochemistry in the UV, X-ray microprobe studies, X-ray microscopy, X-ray holography, X-ray crystallography, Mossbauer spectroscopy, nuclear spectroscopy, neutron production, photon activation therapy and broadband synchrotron as a probe of fast reaction in the IR and near IR.

  10. The phase slip factor of the electrostatic cryogenic storage ring CSR

    Science.gov (United States)

    Grieser, Manfred; von Hahn, Robert; Vogel, Stephen; Wolf, Andreas

    2017-07-01

    To determine the momentum spread of an ion beam from the measured revolution frequency distribution, the knowledge of the phase slip factor of the storage ring is necessary. The slip factor was measured for various working points of the cryogenic storage ring CSR at MPI for Nuclear Physics, Heidelberg and was compared with simulations. The predicted functional relationship of the slip factor and the horizontal tune depends on the different islands of stability, which has been experimentally verified. This behavior of the slip factor is in clear contrast to that of magnetic storage rings.

  11. Electron-positron annihilation from 3 to 11 GeV

    Science.gov (United States)

    Darden, C. W.

    The ARGUS collaboration started forming in mid 1978 to build and operate a new magnetic solenoid detector at the storage ring DORIS in Hamburg. With this detector and a rebuilt storage ring it would be possible to unravel the complicated multiparticle decays of charmed baryons and, more exciting, those of the recently discovered Tau mesons. By March of 1981, construction of the detector was well underway. Progress since then to 15 March 1982 is presented.

  12. Beam dynamics and expected performance of Sweden’s new storage-ring light source: MAX IV

    Directory of Open Access Journals (Sweden)

    S. C. Leemann

    2009-12-01

    Full Text Available MAX IV will be Sweden’s next-generation high-performance synchrotron radiation source. The project has recently been granted funding and construction is scheduled to begin in 2010. User operation for a broad and international user community should commence in 2015. The facility is comprised of two storage rings optimized for different wavelength ranges, a linac-based short-pulse facility and a free-electron laser for the production of coherent radiation. The main radiation source of MAX IV will be a 528 m ultralow emittance storage ring operated at 3 GeV for the generation of high-brightness hard x rays. This storage ring was designed to meet the requirements of state-of-the-art insertion devices which will be installed in nineteen 5 m long dispersion-free straight sections. The storage ring is based on a novel multibend achromat design delivering an unprecedented horizontal bare lattice emittance of 0.33 nm rad and a vertical emittance below the 8 pm rad diffraction limit for 1 Å radiation. In this paper we present the beam dynamics considerations behind this storage-ring design and detail its expected unique performance.

  13. Analytical Approach to Eigen-Emittance Evolution in Storage Rings

    Energy Technology Data Exchange (ETDEWEB)

    Nash, Boaz; /SLAC

    2006-05-16

    This dissertation develops the subject of beam evolution in storage rings with nearly uncoupled symplectic linear dynamics. Linear coupling and dissipative/diffusive processes are treated perturbatively. The beam distribution is assumed Gaussian and a function of the invariants. The development requires two pieces: the global invariants and the local stochastic processes which change the emittances, or averages of the invariants. A map based perturbation theory is described, providing explicit expressions for the invariants near each linear resonance, where small perturbations can have a large effect. Emittance evolution is determined by the damping and diffusion coefficients. The discussion is divided into the cases of uniform and non-uniform stochasticity, synchrotron radiation an example of the former and intrabeam scattering the latter. For the uniform case, the beam dynamics is captured by a global diffusion coefficient and damping decrement for each eigen-invariant. Explicit expressions for these quantities near coupling resonances are given. In many cases, they are simply related to the uncoupled values. Near a sum resonance, it is found that one of the damping decrements becomes negative, indicating an anti-damping instability. The formalism is applied to a number of examples, including synchrobetatron coupling caused by a crab cavity, a case of current interest where there is concern about operation near half integer {nu}{sub x}. In the non-uniform case, the moment evolution is computed directly, which is illustrated through the example of intrabeam scattering. Our approach to intrabeam scattering damping and diffusion has the advantage of not requiring a loosely-defined Coulomb Logarithm. It is found that in some situations there is a small difference between our results and the standard approaches such as Bjorken-Mtingwa, which is illustrated by comparison of the two approaches and with a measurement of Au evolution in RHIC. Finally, in combining IBS

  14. Ring wall storages. An essential contribution of the geotechnics to te energy storage; Ringwallspeicher. Ein essentieller Beitrag der Geotechnik zur Energiespeicherung

    Energy Technology Data Exchange (ETDEWEB)

    Popp, Matthias [Matthias Popp Ingenieurbuero Erneuerbare Energien, Energiespeicherung, Wuppertal (Germany)

    2012-11-01

    The author of the contribution under consideration reports on ring wall storages as an essential contribution to the geotechnical engineering for energy storage. At first, renewable energies as well as the storage requirements for the compensation of the volatility of electricity from wind power and solar energy are described. Subsequently, the storage technologies for energy management requirements as well as the need for water and land area of pumped storage systems are presented with special emphasis of ring wall storages.

  15. Cornell Mixing Zone Expert System

    Science.gov (United States)

    This page provides an overview Cornell Mixing Zone Expert System water quality modeling and decision support system designed for environmental impact assessment of mixing zones resulting from wastewater discharge from point sources

  16. Theory and analysis of nonlinear dynamics and stability in storage rings: A working group summary

    Energy Technology Data Exchange (ETDEWEB)

    Chattopadhyay, S.; Audy, P.; Courant, E.D.; Forest, E.; Guignard, G.; Hagel, J.; Heifets, S.; Keil, E.; Kheifets, S.; Mais, H.; Moshammer, H.; Pellegrini, C.; Pilat, F.; Suzuki, T.; Turchetti, G.; Warnock, R.L.

    1988-07-01

    A summary and commentary of the available theoretical and analytical tools and recent advances in the nonlinear dynamics, stability and aperture issues in storage rings are presented. 11 refs., 4 figs.

  17. The European UV/VUV storage ring FEL at ELETTRA: first operation and future prospects

    CERN Document Server

    Walker, R P; Couprie, Marie Emmanuelle; Dattoli, Giuseppe; Eriksson, M; Garzella, D; Giannessi, L; Marsi, M; Poole, M W; Renault, E; Roux, R; Trovò, M; Werin, S; Wille, K

    2001-01-01

    A European project to develop the first storage ring free-electron laser on a third-generation synchrotron radiation facility is presented, including a description of the main features, initial performance at 350 and 220 nm and future prospects.

  18. Response of Charged Particles in a Storage Ring to Gravitational Waves

    Institute of Scientific and Technical Information of China (English)

    DONG Dong; HUANG Chao-Guang

    2003-01-01

    The influence of gravitational waves on the charged particles in a storage ring is studied. It shows thatthe gravitational waves might be directly detected by monitoring the motion of charged particles in a storage ring. Theangular velocity of the charged particles is continually adjustable by changing the initial energy of particles and thestrength of the magnetic field. This feature is very useful for finding the gravitational waves with different frequencies.

  19. Response of Charged Particles in a Storage Ring to Gravitational Waves

    Institute of Scientific and Technical Information of China (English)

    DONGDong; HUANGChao-Guang

    2003-01-01

    The influence of gravitational waves on the charged particles in a storage ring is studied. It shows that the gravitational waves might be directly detected by monitoring the motion of charged particles in a storage ring. The angular velocity of the charged particles is continually adjustable by changing the initial energy of particles and the strength of the magnetic field. This feature is very useful for finding the gravitational waves with different frequencies.

  20. ETEAPOT: symplectic orbit/spin tracking code for all-electric storage rings

    CERN Document Server

    Talman, Richard M

    2015-01-01

    Proposed methods for measuring the electric dipole moment (EDM) of the proton use an intense, polarized proton beam stored in an all-electric storage ring "trap". At the "magic" kinetic energy of 232.792 MeV, proton spins are "frozen", for example always parallel to the instantaneous particle momentum. This paper describes an accelerator simulation code, ETEAPOT, a new component of the Unified Accelerator Libraries (UAL), to be used for long term tracking of particle orbits and spins in electric bend accelerators, in order to simulate EDM storage ring experiments. Though qualitatively much like magnetic rings, the non-constant particle velocity in electric rings give them significantly different properties, especially in weak focusing rings. Like the earlier code TEAPOT (for magnetic ring simulation) this code performs \\emph{exact tracking in an idealized (approximate) lattice} rather than the more conventional approach, which is \\emph{approximate tracking in a more nearly exact lattice.} The BMT equation des...

  1. Electromagnetic cascade in high-energy electron, positron, and photon interactions with intense laser pulses

    Science.gov (United States)

    Bulanov, S. S.; Schroeder, C. B.; Esarey, E.; Leemans, W. P.

    2013-06-01

    The interaction of high-energy electrons, positrons, and photons with intense laser pulses is studied in head-on collision geometry. It is shown that electrons and/or positrons undergo a cascade-type process involving multiple emissions of photons. These photons can consequently convert into electron-positron pairs. As a result charged particles quickly lose their energy developing an exponentially decaying energy distribution, which suppresses the emission of high-energy photons, thus reducing the number of electron-positron pairs being generated. Therefore, this type of interaction suppresses the development of the electromagnetic avalanche-type discharge, i.e., the exponential growth of the number of electrons, positrons, and photons does not occur in the course of interaction. The suppression will occur when three-dimensional effects can be neglected in the transverse particle orbits, i.e., for sufficiently broad laser pulses with intensities that are not too extreme. The final distributions of electrons, positrons, and photons are calculated for the case of a high-energy e-beam interacting with a counterstreaming, short intense laser pulse. The energy loss of the e-beam, which requires a self-consistent quantum description, plays an important role in this process, as well as provides a clear experimental observable for the transition from the classical to quantum regime of interaction.

  2. Preliminary study of EEHG-based superradiant undulator radiation at the HLS-II storage ring

    Science.gov (United States)

    Gao, Wei-Wei; Li, He-Ting; Wang, Lin

    2017-07-01

    We investigate storage ring-based Echo-Enabled Harmonic Generation (EEHG) superradiant undulator radiation as a possible scheme to obtain shorter wavelengths at the HLS-II (Hefei Light Source-II) storage ring. In this paper we give the designation of the storage ring based EEHG up to the 26th harmonic, where 31 nm vacuum ultraviolet light is radiated from an 800 nm seeded laser. The novelty of our design is that both the two dispersion sections of EEHG are realized by the storage ring’s own magnet structure. In particular, the whole ring is used as the first dispersion section, and two modulators of the traditional EEHG can be done with the same undulator. These two dispersion sections are realized by changing the superperiod of the present lattice structure, and more precisely by changing the focusing strengths of the present structure. Since no additional magnets and chicanes are used, the beam circulates around the storage ring repeatedly, and thus this storage ring-based EEHG can have a higher repetition rate than a linac-based EEHG. Supported by National Natural Science Foundation of China (11305170)

  3. A practical method to generate brilliant hard x-rays with a tabletop electron storage ring

    Energy Technology Data Exchange (ETDEWEB)

    Yamada, H. [Ritsumeikan Univ., Shiga (Japan); Amano, D.; Miyade, H. [Sumitomo Heavy Industries, Ltd., Tanashi-City (Japan)

    1995-12-31

    With electron storage rings not only synchrotron radiation(SR) but also bremsstrahlung(BS) from a thin target placed in the electron orbit are mechanisms to generate brilliant x-ray beams. The calculated brilliance of BS with a 50 MeV storage ring, which is nearly 10{sup 13} photons/s, mrad{sup 2}, mm{sup 2}, 0.1% band width for 100 keV x-rays, exceeds that of SR from a 1 GeV storage ring. This photon energy spectrum is almost constant and extend up to the electron energy. The reasons for this high brilliance with this new radiation scheme is that the electron beams penetrating the thin target are utilized repeatedly, the narrow angular divergence of BS is determined by the kinematics of relativistic electron as same as SR, and the x-ray source size of the order of 1 {mu}m is determined by the size of thin target instead of electron beam sizes. Continuous injection of electron beam to the storage ring at full energy is the way to keep high and constant beam current. Peak current and repetition rate determine x-ray out put power. Note that the power of x-ray beam is also provided from a RF cavity of the storage ring. In this paper we will report some experimental results and discuss further application on a coherent bremsstrahlung generated from a set of stacked foils placed in the electron orbit of the ring. Resulting from these investigations the photon storage ring which is based on a 50 MeV exact circular electron storage ring could provide wide range of coherent and incoherent radiations from far infrared to hard x-ray in a practical amount of radiation power.

  4. A review of methods for experimentally determining linear optics in storage rings

    Energy Technology Data Exchange (ETDEWEB)

    Safranek, J.

    1995-12-31

    In order to maximize the brightness and provide sufficient dynamic aperture in synchrotron radiation storage rings, one must understand and control the linear optics. Control of the horizontal beta function and dispersion is important for minimizing the horizontal beam size. Control of the skew gradient distribution is important for minimizing the vertical size. In this paper, various methods for experimentally determining the optics in a storage ring will be reviewed. Recent work at the National Synchrotron Light Source X-Ray Ring will be presented as well as work done at laboratories worldwide.

  5. Generation of a neutral, high-density electron-positron plasma in the laboratory

    CERN Document Server

    Sarri, G; Cole, J; Schumaker, W; Di Piazza, A; Reville, B; Doria, D; Dromey, B; Gizzi, L; Green, A; Grittani, G; Kar, S; Keitel, C H; Krushelnick, K; Kushel, S; Mangles, S; Najmudin, Z; Thomas, A G R; Vargas, M; Zepf, M

    2013-01-01

    We report on the laser-driven generation of purely neutral, relativistic electron-positron pair plasmas. The overall charge neutrality, high average Lorentz factor ($\\gamma_{e/p} \\approx 15$), small divergence ($\\theta_{e/p} \\approx 10 - 20$ mrad), and high density ($n_{e/p}\\simeq 10^{15}$cm$^{-3}$) of these plasmas open the pathway for the experimental study of the dynamics of this exotic state of matter, in regimes that are of relevance to electron-positron astrophysical plasmas.

  6. Linear electrostatic waves in a three-component electron-positron-ion plasma

    Energy Technology Data Exchange (ETDEWEB)

    Mugemana, A., E-mail: mugemanaa@gmail.com; Moolla, S. [School of Chemistry and Physics, University of KwaZulu-Natal, Durban 4000 (South Africa); Lazarus, I. J. [Department of Mathematics, Statistics and Physics, Durban University of Technology, Durban 4000 (South Africa)

    2014-12-15

    Analytical linear electrostatic waves in a magnetized three-component electron-positron-ion plasma are studied in the low-frequency limit. By using the continuity and momentum equations with Poisson's equation, the dispersion relation for the electron-positron-ion plasma consisting of cool ions, and hot Boltzmann electrons and positrons is derived. In the linear regime, the propagation of two possible modes and their evolution are studied. In the cases of parallel and perpendicular propagation, it is shown that these two possible modes are always stable. The present investigation contributes to nonlinear propagation of electrostatic waves in space and the laboratory.

  7. Storage life of silicone rubber sealing ring used in solid rocket motor

    Institute of Scientific and Technical Information of China (English)

    Liu Weikai; He Guoqiang

    2014-01-01

    It is urgent to carry out detailed research on storage performance of rubber sealing ring to get the criterion for its storage life. This paper acquires material ageing regularity by theoretical analysis and experimental confirmation. On this condition, failure mode and failure criterion of typ-ical sealing structure is studied, and the failure mechanism is found. Thus by analyzing the stress distribution, the relationship between ageing state and sealing condition is established. Rationaliza-tion proposal is put forward and storage life of sealing ring is evaluated. The research mentioned-above has special reference to the design of sealing structures and can provide reference for prolong-ing their service life.

  8. TSR: A Storage Ring for HIE-ISOLDE

    CERN Document Server

    Butler, P A; Blaum, K; Grieser, M; Davinson, T; Woods, P J; Flanagan, K; Freeman, S J; Lazarus, I H; Litvinov, Yu A; Raabe, R; Siesling, E; Wenander, F

    2016-01-01

    It is planned to install the heavy-ion, low-energy ring TSR, currently at the Max-Planck-Institute for Nuclear Physics in Heidelberg, at the HIE-ISOLDE facility in CERN, Geneva. Such a facility will provide a capability for experiments with stored, cooled secondary beams that is rich and varied, spanning from studies of nuclear ground-state properties and reaction studies of astrophysical relevance, to investigations with highly-charged ions and pure isomeric beams. In addition to experiments performed using beams recirculating within the ring, the cooled beams can be extracted and exploited by external spectrometers for high-precision measurements. The capabilities of the ring facility as well as some physics cases will be presented, together with a brief report on the status of the project.

  9. TSR: A storage and cooling ring for HIE-ISOLDE

    Energy Technology Data Exchange (ETDEWEB)

    Butler, P.A. [Oliver Lodge Laboratory, University of Liverpool, Liverpool L69 7ZE (United Kingdom); Blaum, K. [Max-Planck-Institut für Kernphysik, 69117 Heidelberg (Germany); Davinson, T. [School of Physics and Astronomy, University of Edinburgh, Edinburgh EH9 3JZ (United Kingdom); Flanagan, K.; Freeman, S.J. [School of Physics and Astronomy, University of Manchester, Manchester M13 9PL (United Kingdom); Grieser, M. [Max-Planck-Institut für Kernphysik, 69117 Heidelberg (Germany); Lazarus, I.H. [S.T.F.C. Daresbury Laboratory, Warrington WA4 4AD (United Kingdom); Litvinov, Yu.A. [Max-Planck-Institut für Kernphysik, 69117 Heidelberg (Germany); GSI Helmholtzzentrum für Schwerionenforschung, 64291 Darmstadt (Germany); Lotay, G. [Department of Physics, University of Surrey, Guildford GU2 7XH (United Kingdom); Page, R.D. [Oliver Lodge Laboratory, University of Liverpool, Liverpool L69 7ZE (United Kingdom); Raabe, R. [KU Leuven, Instituut voor Kern- en Stralingsfysica, 3001 Leuven (Belgium); Siesling, E.; Wenander, F. [CERN, 1211 Geneva 23 (Switzerland); Woods, P.J. [School of Physics and Astronomy, University of Edinburgh, Edinburgh EH9 3JZ (United Kingdom)

    2016-06-01

    It is planned to install the heavy-ion, low-energy ring TSR, currently at the Max-Planck-Institute for Nuclear Physics in Heidelberg, at the HIE-ISOLDE facility in CERN, Geneva. Such a facility will provide a capability for experiments with stored, cooled secondary beams that is rich and varied, spanning from studies of nuclear ground-state properties and reaction studies of astrophysical relevance, to investigations with highly-charged ions and pure isomeric beams. In addition to experiments performed using beams recirculating within the ring, the cooled beams can be extracted and exploited by external spectrometers for high-precision measurements. The capabilities of the ring facility as well as some physics cases will be presented, together with a brief report on the status of the project.

  10. Spin tune mapping as a novel tool to probe the spin dynamics in storage rings

    Science.gov (United States)

    Saleev, A.; Nikolaev, N. N.; Rathmann, F.; Augustyniak, W.; Bagdasarian, Z.; Bai, M.; Barion, L.; Berz, M.; Chekmenev, S.; Ciullo, G.; Dymov, S.; Eversmann, D.; Gaisser, M.; Gebel, R.; Grigoryev, K.; Grzonka, D.; Guidoboni, G.; Heberling, D.; Hejny, V.; Hempelmann, N.; Hetzel, J.; Hinder, F.; Kacharava, A.; Kamerdzhiev, V.; Keshelashvili, I.; Koop, I.; Kulikov, A.; Lehrach, A.; Lenisa, P.; Lomidze, N.; Lorentz, B.; Maanen, P.; Macharashvili, G.; Magiera, A.; Mchedlishvili, D.; Mey, S.; Müller, F.; Nass, A.; Pesce, A.; Prasuhn, D.; Pretz, J.; Rosenthal, M.; Schmidt, V.; Semertzidis, Y.; Senichev, Y.; Shmakova, V.; Silenko, A.; Slim, J.; Soltner, H.; Stahl, A.; Stassen, R.; Stephenson, E.; Stockhorst, H.; Ströher, H.; Tabidze, M.; Tagliente, G.; Talman, R.; Engblom, P. Thörngren; Trinkel, F.; Uzikov, Yu.; Valdau, Yu.; Valetov, E.; Vassiliev, A.; Weidemann, C.; Wrońska, A.; Wüstner, P.; Zuprański, P.; Zurek, M.; JEDI Collaboration

    2017-07-01

    Precision experiments, such as the search for electric dipole moments of charged particles using storage rings, demand for an understanding of the spin dynamics with unprecedented accuracy. The ultimate aim is to measure the electric dipole moments with a sensitivity up to 15 orders in magnitude better than the magnetic dipole moment of the stored particles. This formidable task requires an understanding of the background to the signal of the electric dipole from rotations of the spins in the spurious magnetic fields of a storage ring. One of the observables, especially sensitive to the imperfection magnetic fields in the ring is the angular orientation of stable spin axis. Up to now, the stable spin axis has never been determined experimentally, and in addition, the JEDI collaboration for the first time succeeded to quantify the background signals that stem from false rotations of the magnetic dipole moments in the horizontal and longitudinal imperfection magnetic fields of the storage ring. To this end, we developed a new method based on the spin tune response of a machine to artificially applied longitudinal magnetic fields. This novel technique, called spin tune mapping, emerges as a very powerful tool to probe the spin dynamics in storage rings. The technique was experimentally tested in 2014 using polarized deuterons stored in the cooler synchrotron COSY, and for the first time, the angular orientation of the stable spin axis at two different locations in the ring has been determined to an unprecedented accuracy of better than 2.8 μ rad .

  11. The new 1.5 GeV storage ring for synchrotron radiation: MAX II

    Science.gov (United States)

    Andersson, Å.; Eriksson, M.; Lindgren, L.-J.; Röjsel, P.; Werin, S.

    1995-02-01

    The MAX laboratory at Lund University, Sweden, today operates an accelerator system consisting of a 100 MeV racetrack microtron and a 550 MeV storage ring (MAX I). At the moment (July 1994) a new storage ring MAX II is near completion and will start first injections within 2 months. This work gives an overview of the MAX II project including the first beamlines and a description of the accelerator system. MAX II is a 1.5 GeV third generation light source optimized for the VUV and soft-x-ray region. It consists of a ten cell double bend achromat lattice forming the 90 m circumference ring. Injection is done at 500 MeV from the existing storage ring MAX I, and ramping up to full energy will take place in MAX II. The straight sections have a length of 3.2 m and eight sections are free to house insertion devices. At start up the ring will be equipped with one 7.5 T superconducting wiggler and one 1.8 T multipole wiggler. Two more undulators are ordered and under construction. To be able to achieve the project a few shortcuts have been made in the design of the storage ring: (1) Nonzero dispersion is allowed in the straight sections, (2) chromaticity correction is built into the quadrupole magnets, and (3) the length of the straight sections is limited to 3.2 m. The project is progressing on time. Extraction of an electron beam from the MAX I storage ring has been achieved and has successfully been transported into the MAX II building. The MAX II ring is under assembly with most of the sections already mounted. First injection is planned to take place in August 1994.

  12. On the robustness of the localized spatiotemporal structures in electron-positron-ion plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Mahajan, S.M. [Univ. of Texas, Austin, TX (United States). Institute for Fusion Studies; Berezhiani, V.I. [Univ. of Texas, Austin, TX (United States). Institute for Fusion Studies]|[Institute of Physics, Tbilisi (Russian Federation). Dept. of Plasma Physics; Miklaszewski, R. [Institute of Plasma Physics and Laser Microfusion, Warsaw (Poland)

    1998-04-01

    It is shown that, in an electron-positron plasma with a small fraction of ions, large-amplitude localized spatiotemporal structures (light bullets) can be readily generated and sustained. These light bullets are found to be exceptionally robust: they can emerge from a large variety of initial field distributions and are remarkably stable.

  13. Neutrino production of electron-positron pairs at excited Landau levels in a strong magnetic field

    CERN Document Server

    Kuznetsov, A V; Savin, V N

    2014-01-01

    The process of neutrino production of electron positron pairs in a magnetic field of arbitrary strength, where electrons and positrons can be created in the states corresponding to excited Landau levels, is analysed. The mean value of the neutrino energy loss due to the process $\

  14. Large Amplitude Low Frequency Waves in a Magnetized Nonuniform Electron-Positron-Ion Plasma

    Institute of Scientific and Technical Information of China (English)

    Q. Haque; H. Saleem

    2004-01-01

    @@ It is shown that the large amplitude low-frequency electromagnetic drift waves in electron-positron-ion plasmas might give rise to dipolar vortices. A linear dispersion relation of several coupled electrostatic and electromagnetic low-frequency modes is obtained. The relevance of this work to both laboratory and astrophysical situations is pointed out.

  15. Electron-Positron to Nucleon-Antinucleon Pair at Threshold and Proton Form Factor

    CERN Document Server

    Yan, Y; Kobdaj, C; Suebka, P

    2009-01-01

    The reactions of electron-positron to nucleon-antinucleon pair at energy threshold are studied in a non-perturbative quark model. The puzzling experimental result that the ratio of the cross section of electron-positron to proton-antiproton to the one of electron-positron to neutron-antineutron is smaller than 1 can be understood in the framework of the phenomenological nonrelativistic quark model and the theoretical predictions for the time-like proton form factor at energy threshold are well consistent with the experimental data. The work suggests that the two-step process, in which the primary quark-antiquark pair forms first a vector meson which in turn decays into a hadron pair, is dominant over the one-step process in which the primary quark-antiquark pair is directly dressed by additional quark-antiquark pairs to form a hadron pair. The experimental data on the reactions of electron-positron to nucleon-antinucleon strongly suggest the reported vector meson omega(1930) to be a 2D-wave particle, while th...

  16. Tuning laser produced electron-positron jets for lab-astrophysics experiment

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Hui [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Fiuza, F. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Hazi, A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Kemp, A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Link, A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Pollock, B. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Marley, E. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Nagel, S. R. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Park, J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Schneider, M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Shepherd, R. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Tommasini, R. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Wilks, S. C. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Williams, G. J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Barnak, D. [Univ. of Rochester, NY (United States). Lab. for Laser Energetics (LLE); Chang, P-Y. [Univ. of Rochester, NY (United States). Lab. for Laser Energetics (LLE); Fiksel, G. [Univ. of Rochester, NY (United States). Lab. for Laser Energetics (LLE); Glebov, V. [Univ. of Rochester, NY (United States). Lab. for Laser Energetics (LLE); Meyerhofer, D. D. [Univ. of Rochester, NY (United States). Lab. for Laser Energetics (LLE); Myatt, J. F. [Univ. of Rochester, NY (United States). Lab. for Laser Energetics (LLE); Stoeckel, C. [Univ. of Rochester, NY (United States). Lab. for Laser Energetics (LLE); Nakai, M. [Osaka Univ. (Japan). ILE; Arikawa, Y. [Osaka Univ. (Japan). ILE; Azechi, H. [Osaka Univ. (Japan). ILE; Fujioka, S. [Osaka Univ. (Japan). ILE; Hosoda, H. [Osaka Univ. (Japan). ILE; Kojima, S. [Osaka Univ. (Japan). ILE; Miyanga, N. [Osaka Univ. (Japan). ILE; Morita, T. [Osaka Univ. (Japan). ILE; Moritaka, T. [Osaka Univ. (Japan). ILE; Nagai, T. [Osaka Univ. (Japan). ILE; Namimoto, T. [Osaka Univ. (Japan). ILE; Nishimura, H. [Osaka Univ. (Japan). ILE; Ozaki, T. [Osaka Univ. (Japan). ILE; Sakawa, Y. [Osaka Univ. (Japan). ILE; Takabe, H. [Osaka Univ. (Japan). ILE; Zhang, Z. [Osaka Univ. (Japan). ILE

    2015-02-23

    This paper reviews the experiments on the laser produced electron-positron jets using large laser facilities worldwide. The goal of the experiments was to optimize the parameter of the pair jets for their potential applications in laboratory-astrophysical experiment. Results on tuning the pair jet’s energy, number, emittance and magnetic collimation will be presented.

  17. Universality of multiplicity distribution in proton-proton and electron-positron collisions

    CERN Document Server

    Bzdak, Adam

    2015-01-01

    It is argued that the multiplicity distribution in proton-proton ($pp$) collisions, which is often parameterized by the negative binomial distribution, results from the multiplicity distribution measured in electron-positron ($e^{+}e^{-}$) collisions, once the fluctuating energy carried by two leading protons in $pp$ is taken into account.

  18. A Study of Storage Ring Requirements for an Explosive Detection System Using NRA Method

    CERN Document Server

    Wang, Tai-Sen

    2005-01-01

    The technical feasibility of an explosives detection system based on the nuclear resonance absorption (NRA) of gamma rays in nitrogen-rich materials was demonstrated at Los Alamos National Laboratory (LANL) in 1993 by using an RFQ proton accelerator and a tomographic imaging prototype.* The study is being continued recently to examine deployment of such an active interrogation system in realistic scenarios. The approach is to use a cyclotron and electron-cooling-equipped storage rings(s) to provide the high quality and high current proton beam needed in a practical application. In this work, we investigate the storage ring requirements for a variant of the airport luggage inspection system considered in the earlier LANL experiments. Estimations are carried out based on the required inspection throughput, the gamma ray yield, the proton beam emittance growth due to scattering with the photon-production target, beam current limit in the storage ring, and the electron cooling rate. Studies using scaling and reas...

  19. The injector of the storage ring ANKA; Der Injektor der Speicherringanlage ANKA

    Energy Technology Data Exchange (ETDEWEB)

    Einfeld, D.; Pont, M. [Forschungszentrum Karlsruhe GmbH Technik und Umwelt (Germany). FGS

    2000-07-01

    The injector of the ANKA storage ring should create a beam of electrons and accelerate them to 500 MeV ready to be injected into the storage ring. This is accomplished with a combination of a microtron and a booster synchrotron, which we call the injector system of ANKA. The microtron delivers a pulse of 1 {mu}sec length with a current of 10 mA. The energy of the electrons when leaving the microtron is 53 MeV. The injection transfer line transports this beam to the booster synchrotron where the electron beam is accelerated to 500 MeV. At 500 MeV another transfer line, the so called extraction transfer line transports the beam to the storage ring. The repetition rate is 1 Hz. (orig.)

  20. Intense X-ray sources based on compton scattering in laser electron storage rings

    CERN Document Server

    Gladkikh, P I; Karnaukhov, I M

    2002-01-01

    The main problem of the designing of intense X-ray sources based on Compton scattering in laser-electron storage ring is associated with large steady-state electron beam energy spread. In paper the principles of the development of compact storage ring lattice with large RF-acceptance and negligible chromatic effects at interaction point are considered. The storage ring with electron beam energy over the range 100-400 MeV that allows generating intense VUV from bending magnets, X-ray up to 280 keV with rate up to 10 sup 1 sup 4 photons/s and gamma-beam up to 2.8 MeV for neutron generation on beryllium target is proposed.

  1. Ultrashort x-ray pulse generation by electron beam slicing in storage rings

    Directory of Open Access Journals (Sweden)

    A. He

    2014-04-01

    Full Text Available We propose a new method to generate ultrashort x-ray pulses using focused short low energy (∼20  MeV electron bunches to create short slices of electrons from the circulating electron bunches in a synchrotron radiation storage ring. When a low energy electron bunch crosses from the top of a high energy storage ring electron bunch, its Coulomb force will kick a short slice from the core of the storage ring electron bunch. The separated slices, when passing through an undulator, will radiate ultrashort x-ray pulses at about 160 fs. We discuss the advantages, challenges, and provide data which confirm the feasibility of this new method.

  2. Photoswitchable Molecular Rings for Solar-Thermal Energy Storage

    Energy Technology Data Exchange (ETDEWEB)

    Durgun, E; Grossman, JC

    2013-03-21

    Solar-thermal fuels reversibly store solar energy in the chemical bonds of molecules by photoconversion, and can release this stored energy in the form of heat upon activation. Many conventional photoswichable molecules could be considered as solar thermal fuels, although they suffer from low energy density or short lifetime in the photoinduced high-energy metastable state, rendering their practical use unfeasible. We present a new approach to the design of chemistries for solar thermal fuel applications, wherein well-known photoswitchable molecules are connected by different linker agents to form molecular rings. This approach allows for a significant increase in both the amount of stored energy per molecule and the stability of the fuels. Our results suggest a range of possibilities for tuning the energy density and thermal stability as a function of the type of the photoswitchable molecule, the ring size, or the type of linkers.

  3. Photoswitchable Molecular Rings for Solar-Thermal Energy Storage.

    Science.gov (United States)

    Durgun, E; Grossman, Jeffrey C

    2013-03-21

    Solar-thermal fuels reversibly store solar energy in the chemical bonds of molecules by photoconversion, and can release this stored energy in the form of heat upon activation. Many conventional photoswichable molecules could be considered as solar thermal fuels, although they suffer from low energy density or short lifetime in the photoinduced high-energy metastable state, rendering their practical use unfeasible. We present a new approach to the design of chemistries for solar thermal fuel applications, wherein well-known photoswitchable molecules are connected by different linker agents to form molecular rings. This approach allows for a significant increase in both the amount of stored energy per molecule and the stability of the fuels. Our results suggest a range of possibilities for tuning the energy density and thermal stability as a function of the type of the photoswitchable molecule, the ring size, or the type of linkers.

  4. Steady State Microbunching for High Brilliance and High Repetition Rate Storage Ring-Based Light Sources

    Energy Technology Data Exchange (ETDEWEB)

    Chao, Alex; Ratner, Daniel; /SLAC; Jiao, Yi; /Beijing, Inst. High Energy Phys.

    2012-09-06

    Electron-based light sources have proven to be effective sources of high brilliance, high frequency radiation. Such sources are typically either linac-Free Electron Laser (FEL) or storage ring types. The linac-FEL type has high brilliance (because the beam is microbunched) but low repetition rate. The storage ring type has high repetition rate (rapid beam circulation) but comparatively low brilliance or coherence. We propose to explore the feasibility of a microbunched beam in a storage ring that promises high repetition rate and high brilliance. The steady-state-micro-bunch (SSMB) beam in storage ring could provide CW sources for THz, EUV, or soft X-rays. Several SSMB mechanisms have been suggested recently, and in this report, we review a number of these SSMB concepts as promising directions for high brilliance, high repetition rate light sources of the future. The trick of SSMB lies in the RF system, together with the associated synchrotron beam dynamics, of the storage ring. Considering various different RF arrangements, there could be considered a number of scenarios of the SSMB. In this report, we arrange these scenarios more or less in order of the envisioned degree of technical challenge to the RF system, and not in the chronological order of their original references. Once the stored beam is steady-state microbunched in a storage ring, it passes through a radiator repeatedly every turn (or few turns). The radiator extracts a small fraction of the beam energy as coherent radiation with a wavelength corresponding to the microbunched period of the beam. In contrast to an FEL, this radiator is not needed to generate the microbunching (as required e.g. by SASE FELs or seeded FELs), so the radiator can be comparatively simple and short.

  5. Steady State Microbunching for High Brilliance and High Repetition Rate Storage Ring-Based Light Sources

    Energy Technology Data Exchange (ETDEWEB)

    Chao, Alex; Ratner, Daniel; /SLAC; Jiao, Yi; /Beijing, Inst. High Energy Phys.

    2012-09-06

    Electron-based light sources have proven to be effective sources of high brilliance, high frequency radiation. Such sources are typically either linac-Free Electron Laser (FEL) or storage ring types. The linac-FEL type has high brilliance (because the beam is microbunched) but low repetition rate. The storage ring type has high repetition rate (rapid beam circulation) but comparatively low brilliance or coherence. We propose to explore the feasibility of a microbunched beam in a storage ring that promises high repetition rate and high brilliance. The steady-state-micro-bunch (SSMB) beam in storage ring could provide CW sources for THz, EUV, or soft X-rays. Several SSMB mechanisms have been suggested recently, and in this report, we review a number of these SSMB concepts as promising directions for high brilliance, high repetition rate light sources of the future. The trick of SSMB lies in the RF system, together with the associated synchrotron beam dynamics, of the storage ring. Considering various different RF arrangements, there could be considered a number of scenarios of the SSMB. In this report, we arrange these scenarios more or less in order of the envisioned degree of technical challenge to the RF system, and not in the chronological order of their original references. Once the stored beam is steady-state microbunched in a storage ring, it passes through a radiator repeatedly every turn (or few turns). The radiator extracts a small fraction of the beam energy as coherent radiation with a wavelength corresponding to the microbunched period of the beam. In contrast to an FEL, this radiator is not needed to generate the microbunching (as required e.g. by SASE FELs or seeded FELs), so the radiator can be comparatively simple and short.

  6. Commissioning of the DESIREE storage rings - a new facility for cold ion-ion collisions

    Science.gov (United States)

    Gatchell, M.; Schmidt, H. T.; Thomas, R. D.; Rosén, S.; Reinhed, P.; Löfgren, P.; Brännholm, L.; Blom, M.; Björkhage, M.; Bäckström, E.; Alexander, J. D.; Leontein, S.; Hanstorp, D.; Zettergren, H.; Liljeby, L.; Källberg, A.; Simonsson, A.; Hellberg, F.; Mannervik, S.; Larsson, M.; Geppert, W. D.; Rensfelt, K. G.; Danared, H.; Paál, A.; Masuda, M.; Halldén, P.; Andler, G.; Stockett, M. H.; Chen, T.; Källersjö, G.; Weimer, J.; Hansen, K.; Hartman, H.; Cederquist, H.

    2014-04-01

    We report on the ongoing commissioning of the Double ElectroStatic Ion Ring ExpEriment, DESIREE, at Stockholm University. Beams of atomic carbon anions (C-) and smaller carbon anion molecules (C-2, C-3, C-4 etc.) have been produced in a sputter ion source, accelerated to 10 keV or 20 keV, and stored successfully in the two electrostatic rings. The rings are enclosed in a common vacuum chamber cooled to below 13 Kelvin. The DESIREE facility allows for studies of internally relaxed single isolated atomic, molecular and cluster ions and for collision experiments between cat- and anions down to very low center-of-mass collision energies (meV scale). The total thermal load of the vacuum chamber at this temperature is measured to be 32 W. The decay rates of stored ion beams have two components: a non-exponential component caused by the space charge of the beam itself which dominates at early times and an exponential term from the neutralization of the beam in collisions with residual gas at later times. The residual gas limited storage lifetime of carbon anions in the symmetric ring is over seven minutes while the 1/e lifetime in the asymmetric ring is measured to be about 30 seconds. Although we aim to improve the storage in the second ring, the number of stored ions are now sufficient for many merged beams experiments with positive and negative ions requiring milliseconds to seconds ion storage.

  7. Design Work for the High-Energy Storage Ring for Antiprotons of the Future GSI Project

    CERN Document Server

    Lehrach, Andreas; Boine-Frankenheim, Oliver; Bongardt, Klaus; Dietrich, J; Dolinskii, Alexei V; Eichhorn, Ralf; Gålnander, B; Hinterberger, Frank; Lorentz, Bernd; Maier, Rudolf; Martin, Siegfried; Prasuhn, Dieter; Reistad, Dag; Senichev, Yurij; Senicheva, Eugenia; Steck, Markus; Stockhorst, Hans; Tölle, Raimund; Zaplatin, Evgeny

    2005-01-01

    The High-Energy Storage Ring (HESR) of the future international Facility for Antiproton and Ion Research (FAIR) at GSI in Darmstadt is planned as an antiproton cooler and storage ring in the momentum range from 1.5 to 15 GeV/c. The design work for the HESR is organized by a consortium with scientists from FZ Jülich, GSI Darmstadt and TSL Uppsala. An important feature of the new facility is the combination of phase space cooled beams with internal targets, resulting in demanding beam parameter in two operation modes: high luminosity mode with beam intensities up to few times 1011

  8. Design and fabrication of the first quadrupole magnet for the ILSF storage ring

    Directory of Open Access Journals (Sweden)

    F Saeidi

    2015-09-01

    Full Text Available The Iranian Light Source Facility (ILSF is a new 3 GeV third generation synchrotron light source which is consisted of several pre-accelerators and a storage ring with the beam current of 400 mA. Based on the main lattice candidate, the storage ring includes of 100 dipoles, 320 quadrupoles and 320 sextupole magnets. To develop fabrication procedures and techniques and to compare the measurement results with the design data, a series of lattice magnets have been fabricated inside Iran with internal industries. In this article the first prototype quadrupole magnet fabrication process has been described

  9. Preliminary application of turn-by-turn data analysis to the SSRF storage ring

    Institute of Scientific and Technical Information of China (English)

    CHEN Jian-Hui; ZHAO Zhen-Tang

    2009-01-01

    There is growing interest in utilizing the beam position monitor turn-by-turn (TBT) data to debug accelerators. TBT data can be used to determine the linear optics, coupled optics and nonlinear behaviors of the storage ring lattice. This is not only a useful complement to other methods of determining the linear optics such as LOCO, but also provides a possibility to uncover more hidden phenomena. In this paper, a preliminary application of a β function measurement to the SSRF storage ring is presented.

  10. A Genetic Algorithm for Chromaticity Correction in Diffraction Limited Storage Rings

    CERN Document Server

    Ehrlichman, Michael

    2016-01-01

    An multi-objective genetic algorithm is developed for optimizing nonlinearities in diffraction limited storage rings. This algorithm determines sextupole and octupole strengths for chromaticity correction that deliver optimized dynamic aperture and beam lifetime. The algorithm makes use of dominance constraints to breed desirable properties into the early generations. The momentum aperture is optimized indirectly by constraining the chromatic tune footprint and optimizing the off-energy dynamic aperture. The result is an effective and computationally efficient technique for correcting chromaticity in a storage ring while maintaining optimal dynamic aperture and beam lifetime. This framework was developed for the Swiss Light Source (SLS) upgrade project.

  11. New chromaticity compensation approach and dynamic aperture increase in the SSRF storage ring

    Institute of Scientific and Technical Information of China (English)

    TIAN Shun-Qiang; HOU Jie; CHEN Guang-Ling; LIU Gui-Min

    2008-01-01

    Strong chromatic sextupoles used to compensate natural chromaticities in the third generation light source storage ring usually reduce dynamic aperture drastically.Many optimization methods can be used to find solutions that provide large dynamic apertures.This paper discusses a new optimization approach of sextupole strengths with step-by-step procedure,which is applied in the SSRF storage ring,and a better solution is obtained.Investigating driving terms generated by the sextupoles in every step can analyze their convergences and guide the weight setting among different terms in object function of the single resonance approach based on the perturbation theory.

  12. Optics for the lattice of the compact storage ring for a Compton X-ray source

    Institute of Scientific and Technical Information of China (English)

    YU Pei-Cheng; WANG Yu; SHEN Xiao-zhe; HUANG Wen-Hui; YAN Li-xin; DU Ying-Chao; LI Ren-Kai; TANG Chuan-Xiang

    2009-01-01

    We present two types of optics for the lattice of a compact storage ring for a Compton X-ray source.The optics design for different operation modes of the storage ring are discussed in detail.For the pulse mode optics,an IBS-suppression scheme is applied to optimize the optics for lower IBS emittance growth rate;as for the steady mode,the method to control momentum compact factor is adopted[Gladkikh P,Phys.Rev.ST Accel.Beams 8,050702]to obtain stability of the electron beam.

  13. The heavy ion cooler-storage-ring project (HIRFL-CSR) at Lanzhou

    CERN Document Server

    Xia, J W; Wei, B W; Yuan, Y J; Song, M T; Zhang, W Z; Yang, X D; Yuan Ping; Gao, D Q; Zhao, H W; Yang, X T; Xiao, G Q; Man, K T; Dang, J R; Cai, X H; Wang, Y F; Tang, J Y; Qiao, W M; Rao, Y N; He, Y; Mao, L Z; Zhou, Z Z

    2002-01-01

    HIRFL-CSR, a new ion Cooler-Storage-Ring (CSR) project, is the post-acceleration system of the Heavy Ion Research Facility in Lanzhou (HIRFL). It consists of a main ring (CSRm) and an experimental ring (CSRe). From the HIRFL cyclotron system the heavy ions will be accumulated, cooled and accelerated in the CSRm, then extracted fast to produce radioactive ion beams (RIB) or highly charged heavy ions. Those secondary beams will be accepted and stored by the CSRe for many internal-target experiments with electron cooling.

  14. Interplay of Touschek scattering, intrabeam scattering, and rf cavities in ultralow-emittance storage rings

    Directory of Open Access Journals (Sweden)

    S. C. Leemann

    2014-05-01

    Full Text Available The latest generation of storage ring-based light sources employs multibend achromat lattices to achieve ultralow emittance. These lattices make use of a large number of weak bending magnets which considerably reduces the amount of power radiated in the dipoles in comparison to power radiated from insertion devices. Therefore, in such storage rings, parameters such as emittance, energy spread, and radiated power are—unlike 3rd generation storage rings—no longer constant during a typical user shift. Instead, they depend on several varying parameters such as insertion device gap settings, bunch charge, bunch length, etc. Since the charge per bunch is usually high, intrabeam scattering in medium-energy storage rings with ultralow emittance becomes very strong. This creates a dependence of emittance on stored current. Furthermore, since the bunch length is adjusted with rf cavities but is also varied as insertion device gaps change, the emittance blowup from intrabeam scattering is not constant either. Therefore, the emittance, bunch length, and hence the resulting Touschek lifetime have to be calculated in a self-consistent fashion with 6D tracking taking into account not only the bare lattice and rf cavity settings, but also momentary bunch charge and gap settings. Using the MAX IV 3 GeV storage ring as an example, this paper demonstrates the intricate interplay between transverse emittance (insertion devices, emittance coupling, longitudinal emittance (tuning of main cavities as well as harmonic cavities, and choice of stored current in an ultralow-emittance storage ring as well as some implications for brightness optimization.

  15. Joseph Cornell's flow learning use

    OpenAIRE

    Lužnik, Anja

    2014-01-01

    Natural science is one of the subjects where nature or natural environment can often be used directly for teaching. Joseph Cornell, who introduced Flow Learning, also emphasises this fact. The main focus of my thesis was how Joseph Cornell’s Flow Learning could be used in our primary schools. I selected some learning objectives out of natural science and technology curriculum which could be achieved with the Flow Learning system using Cornell’s activities. I tested my thesis in practice w...

  16. Design of the SSRF storage ring magnet lattice

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The Shanghai Synchrotron Radiation Facility (SSRF) is a proposed 3rd generation light source with 3.5 GeV in energy. It is composed of 20 DBA cells resulting in a ring that is about 10 nm(rad in emittance and 396 m in circumference, and provides 10 straight sections of 7.24 m and other 10 straight sections of 5.0 m for the inclusion of insertion devices, injection components and RF cavities. The lattice has high flexibility, and the tunes and beta functions can be easily adjusted within a wide range to meet the requirements for different operation modes, including high beta mode and hybrid beta mode with and/or without dispersion in straight sections. In this paper, the results of linear optics design and dynamic aperture study are presented.

  17. Limitation on the luminosity of e+e- storage rings due to beamstrahlung

    CERN Document Server

    Telnov, V I

    2013-01-01

    Particle loss due to the emission of single energetic beamstrahlung photons in beam collisions is shown to impose a fundamental limit on storage-ring luminosities at energies greater than 2E~140 GeV for head-on collisions and 2E~40 GeV for crab-waist collisions. Above these threshold energies, the suppression factor due to beamstrahlung scales as 1/E^{4/3}, and for a fixed power of synchrotron radiation, the luminosity L is proportional to R/E^{13/3}, where R is the collider radius. For 2E > 150 GeV, both collision schemes have similar luminosity limits. The luminosities attainable at storage-ring and linear-collider (LC) 2E=240 GeV Higgs factories are comparable; at higher energies, LCs are preferable. This conference paper is based on my recent PRL publication [1], supplemented with additional comments on linac-ring e+e- colliders and ring e+e- colliders with charge compensation (four-beam collisions).

  18. Effects of CSR Generated from Upstream Bends in a Laser Plasma Storage Ring

    Energy Technology Data Exchange (ETDEWEB)

    Mitchell, C.; Qiang, J.; Venturini, M.

    2013-08-28

    The recent proposal [1] of a Laser Plasma Storage Ring (LPSR) envisions the use of a laser-plasma (LP) acceleration module to inject an electron beam into a compact 500 MeV storage ring. Electron bunches generated by LP methods are naturally very short (tens of femtoseconds), presenting peak currents on the order of 10 kA or higher. Of obvious concern is the impact of collective effects and in particular Coherent Synchrotron Radiation (CSR) on the beam dynamics in the storage ring. Available simulation codes (e.g. Elegant [2]) usually include transient CSR effects but neglect the contribution of radiation emitted from trailing magnets. In a compact storage ring, with dipole magnets close to each other, cross talking between different magnets could in principle be important.In this note we investigate this effect for the proposed LPSR and show that, in fact, this effect is relatively small. However our analysis also indicates that CSR effects in general would be quite strong and deserve a a careful study.

  19. Effects of CSR Generated from Upstream Bends in a Laser Plasma Storage Ring

    Energy Technology Data Exchange (ETDEWEB)

    Mitchell, C.; Qiang, J.; Venturini, M.

    2013-08-28

    The recent proposal [1] of a Laser Plasma Storage Ring (LPSR) envisions the use of a laser-plasma (LP) acceleration module to inject an electron beam into a compact 500 MeV storage ring. Electron bunches generated by LP methods are naturally very short (tens of femtoseconds), presenting peak currents on the order of 10 kA or higher. Of obvious concern is the impact of collective effects and in particular Coherent Synchrotron Radiation (CSR) on the beam dynamics in the storage ring. Available simulation codes (e.g. Elegant [2]) usually include transient CSR effects but neglect the contribution of radiation emitted from trailing magnets. In a compact storage ring, with dipole magnets close to each other, cross talking between different magnets could in principle be important.In this note we investigate this effect for the proposed LPSR and show that, in fact, this effect is relatively small. However our analysis also indicates that CSR effects in general would be quite strong and deserve a a careful study.

  20. Compact storage ring to search for the muon electric dipole moment

    NARCIS (Netherlands)

    Adelmann, A.; Kirch, K.; Onderwater, C. J. G.; Schietinger, T.

    2010-01-01

    We present the concept of a compact storage ring of less than 0.5 m orbit radius to search for the electric dipole moment (EDM) of the muon (d(mu)) by adapting the 'frozen spin' method. At existing muon facilities a statistics limited sensitivity of d(mu) similar to 7 x 10(-23) e cm can be achieved

  1. Analysis and correction of linear optics errors, and operational improvements in the Indus-2 storage ring

    Science.gov (United States)

    Husain, Riyasat; Ghodke, A. D.

    2017-08-01

    Estimation and correction of the optics errors in an operational storage ring is always vital to achieve the design performance. To achieve this task, the most suitable and widely used technique, called linear optics from closed orbit (LOCO) is used in almost all storage ring based synchrotron radiation sources. In this technique, based on the response matrix fit, errors in the quadrupole strengths, beam position monitor (BPM) gains, orbit corrector calibration factors etc. can be obtained. For correction of the optics, suitable changes in the quadrupole strengths can be applied through the driving currents of the quadrupole power supplies to achieve the desired optics. The LOCO code has been used at the Indus-2 storage ring for the first time. The estimation of linear beam optics errors and their correction to minimize the distortion of linear beam dynamical parameters by using the installed number of quadrupole power supplies is discussed. After the optics correction, the performance of the storage ring is improved in terms of better beam injection/accumulation, reduced beam loss during energy ramping, and improvement in beam lifetime. It is also useful in controlling the leakage in the orbit bump required for machine studies or for commissioning of new beamlines.

  2. Spin flip by RF-field at storage rings with siberian snakes

    Energy Technology Data Exchange (ETDEWEB)

    Koop, I.; Shatunov, Y. [Budker Institute for Nuclear Physics, Novosibirsk, 630090 (Russia)

    1995-09-01

    The beam dynamics and optics of spin flipping polarized beams with an RF field in storage rings with Siberian Snakes is discussed. The dispersion relations are determined and depolarization of the beams are discussed. (AIP) {copyright} {ital 1995 American Institute of Physics.}

  3. Laser-rf double-resonance spectroscopy in a storage ring

    Science.gov (United States)

    Kristensen, M.; Hangst, J. S.; Jessen, P. S.; Nielsen, J. S.; Poulsen, O.; Shi, P.

    1992-10-01

    Laser-rf double-resonance spectroscopy of the hyperfine transition between F''=0 and F'=1 in the metastable 3S1 state of 6Li+ was performed in 100-keV beam in the storage ring ASTRID. High efficiency of optical pumping was demonstrated for complex pumping schemes. A broadband (dc-6 GHz) rf device was designed and used for rf spectroscopy in the storage ring. The possibility of obtaining coherent rf signals (Ramsey fringes) from successive interactions with the same field was investigated. Important limitations for the coherences due to magnetic-field inhomogeneities were observed. These led to randomization of the atomic polarization during only one turn in the storage ring and completely prevented observation of Ramsey fringes. This situation is different from the case of fundamental particles in a storage ring, where the polarization may be preserved for many round-trips. Limits were put on the demands to beam quality, beam positioning, and magnetic-field quality to overcome the problem. The effects of the rf device on the external degrees of freedom of the ion beam were investigated. Its small aperture substantially reduced the beam lifetime, and at very low rf frequencies the electric field in the rf device was able to excite external transverse resonances in the beam.

  4. Modern Ives-Stilwell Experiments At Storage Rings: Large Boosts Meet High Precision

    CERN Document Server

    Gwinner, G; Geppert, C; Huber, G; Karpuk, S; Krieger, A; Nörtershäuser, W; Novotny, C; Kühl, T; Sanchez, R; Stöhlker, T; Bing, D; Schwalm, D; Wolf, A; Hänsch, T W; Reinhardt, S; Saathoff, G

    2013-01-01

    We give a brief overview of time dilation tests using high-resolution laser spectroscopy at heavy-ion storage rings. We reflect on the various methods used to eliminate the first-order Doppler effect and on the pitfalls encountered, and comment on possible extensions at future facilities providing relativistic heavy ion beams at $\\gamma \\gg 1$.

  5. Stability of Coulomb crystals in a linear Paul trap with storage-ring-like confinement

    DEFF Research Database (Denmark)

    Kjærgaard, Niels; Mølhave, Kristian; Drewsen, Michael

    2002-01-01

    We report experiments on the stability of ion Coulomb crystals in a linear Paul trap with storage-ring-like confinement. The transverse dynamics of charged particles in a trap of this type is analogous to that of a fast beam traveling through a channel with periodic, magnetic alternating gradient...

  6. Observations And Measurements of Anomalous Hollow Electron Beams in a Storage Ring

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Y.K.; Li, J.; /Duke U.; Wu, J.; /SLAC

    2006-02-06

    Anomalous hollow electron beams have been recently observed in the Duke storage ring. With a single bunch beam in a lattice with a negative chromaticity, a hollow beam can be created. This beam consists of a solid core beam inside and a large ring beam outside. In this paper, we report the measurements of the hollow beam phenomenon, including its distinct image pattern and spectrum signature, and its evolution with time. By capturing the post-instability bursting beam, the hollow beam is a unique model system for studying transverse instabilities, in particular, the interplay of the wakefield and lattice nonlinearity. The hollow beam can also be used as a tool to study linear and nonlinear particle dynamics in the storage ring.

  7. NSLS-II storage ring insertion device and front-end commissioning and operation

    Energy Technology Data Exchange (ETDEWEB)

    Wang, G., E-mail: gwang@bnl.gov; Shaftan, T.; Amundsen, C.; Bassi, G.; Bengtsson, J.; Blednykh, A.; Blum, E.; Cheng, W.; Choi, J.; Chubar, O.; Corwin, T.; Davidsaver, M.; Doom, L.; Guo, W.; Harder, D.; Hidaka, Y.; Hu, Y.; Ilinski, P.; Kitegi, C.; Kramer, S. [Brookhaven National Laboratory, Upton, NY 11973 (United States); and others

    2016-07-27

    The National Synchrotron Light Source II (NSLS-II) is a state of the art 3 GeV third generation light source at Brookhaven National Laboratory. During spring/ summer of 2014, the storage ring was commissioned up to 50 mA without insertion devices. In the fall of 2014, we began commissioning of the project beamlines, which included seven insertion devices on six ID ports. Beamlines IXS, HXN, CSX-1, CSX-2, CHX, SRX, and XPD-1 consist of elliptically polarized undulator (EPU), damping wigglers (DW) and in-vacuum undulators (IVU) covering from VUV to hard x-ray range. In this paper, experience with commissioning and operation is discussed. We focus on reaching storage ring performance with IDs, including injection, design emittance, compensation of orbit distortions caused by ID residual field, source point stability, beam alignment and tools for control, monitoring and protection of the ring chambers from ID radiation.

  8. Towards the ultimate storage ring: the lattice design for Beijing Advanced Photon Source

    CERN Document Server

    Gang, Xu

    2013-01-01

    A storage ring-based light source, Beijing Advanced Photon Source (BAPS) is proposed to store 5-GeV low-emittance electron beam and to provide high-brilliance coherent radiation. In this paper, we report our efforts of pushing down the emittance of BAPS to approach the so-called ultimate storage ring, while fixing the circumference to about 1200 m. To help dealing with the challenge of beam dynamics associated with the intrinsic very strong nonlinearities in an ultralow-emittance ring, a combination of several progressive technologies is used in the linear optics design and nonlinear optimization, such as modified theoretical minimum emittance cell with small-aperture magnets, quasi-3rd-order achromat, theoretical analyzer based on Lie Algebra and Hamiltonian analysis, multi-objective genetic algorithm, and frequency map analysis. These technologies enable us to obtain satisfactory beam dynamics in one lattice design with natural emittance of 75 pm.

  9. Resonant two-photon annihilation of an electron-positron pair in a pulsed electromagnetic wave

    Science.gov (United States)

    Voroshilo, A. I.; Roshchupkin, S. P.; Nedoreshta, V. N.

    2016-09-01

    Two-photon annihilation of an electron-positron pair in the field of a plane low-intensity circularly polarized pulsed electromagnetic wave was studied. The conditions for resonance of the process which are related to an intermediate particle that falls within the mass shell are studied. In the resonant approximation the probability of the process was obtained. It is demonstrated that the resonant probability of two-photon annihilation of an electron-positron pair may be several orders of magnitude higher than the probability of this process in the absence of the external field. The obtained results may be experimentally verified by the laser facilities of the international megaprojects, for example, SLAC (National Accelerator Laboratory), FAIR (Facility for Antiproton and Ion Research), and XFEL (European X-Ray Free-Electron Laser).

  10. Charged Particles Multiplicity and Scaling Violation of Fragmentation Functions in Electron-Positron Annihilation

    CERN Document Server

    Ghaffary, Tooraj

    2016-01-01

    In electron positron annihilation, changing quarks into the final hadron states is being described by fragmentation function. Based on the scaling hypothesis, this function will be independent from the center of mass energy. Gluon radiation violates the scaling feature. Transverse momentum distribution plays an important role in scaling violation of fragmentation functions. In this article, by the use of data resulted from the annihilation process of electron positron in AMY detector at 60 GeV center of mass energy, first, charged particles multiplicity distribution will be obtained and it will be fitted with the KNO scaling. Furthermore, momentum spectra of charged particles and momentum distribution respect to the jet axis will be obtained. Then, the results will be compared regarding the different models of QCD; as well, the distribution of fragmentation functions and scaling violations will be studied. It is being expected that the scaling violations of the fragmentation functions of gluon jet are stronge...

  11. Electroweak interactions between intense neutrino beams and dense electron-positron magneto-plasmas

    CERN Document Server

    Tsintsadze, N L; Stenflo, L

    2003-01-01

    The electroweak coupling between intense neutrino beams and strongly degenerate relativistic dense electron-positron magneto-plasmas is considered. The intense neutrino bursts interact with the plasma due to the weak Fermi interaction force, and their dynamics is governed by a kinetic equation. Our objective here is to develop a kinetic equation for a degenerate neutrino gas and to use that equation to derive relativistic magnetohydrodynamic equations. The latter are useful for studying numerous collective processes when intense neutrino beams nonlinearly interact with degenerate, relativistic, dense electron-positron plasmas in strong magnetic fields. If the number densities of the plasma particles are of the order of 10 sup 3 sup 3 cm sup - sup 3 , the pair plasma becomes ultra-relativistic, which strongly affects the potential energy of the weak Fermi interaction. The new system of equations allows several neutrino-driven streaming instabilities involving new types of relativistic Alfven-like waves, The re...

  12. Spin tune mapping as a novel tool to probe the spin dynamics in storage rings

    Directory of Open Access Journals (Sweden)

    2017-07-01

    Full Text Available Precision experiments, such as the search for electric dipole moments of charged particles using storage rings, demand for an understanding of the spin dynamics with unprecedented accuracy. The ultimate aim is to measure the electric dipole moments with a sensitivity up to 15 orders in magnitude better than the magnetic dipole moment of the stored particles. This formidable task requires an understanding of the background to the signal of the electric dipole from rotations of the spins in the spurious magnetic fields of a storage ring. One of the observables, especially sensitive to the imperfection magnetic fields in the ring is the angular orientation of stable spin axis. Up to now, the stable spin axis has never been determined experimentally, and in addition, the JEDI collaboration for the first time succeeded to quantify the background signals that stem from false rotations of the magnetic dipole moments in the horizontal and longitudinal imperfection magnetic fields of the storage ring. To this end, we developed a new method based on the spin tune response of a machine to artificially applied longitudinal magnetic fields. This novel technique, called spin tune mapping, emerges as a very powerful tool to probe the spin dynamics in storage rings. The technique was experimentally tested in 2014 using polarized deuterons stored in the cooler synchrotron COSY, and for the first time, the angular orientation of the stable spin axis at two different locations in the ring has been determined to an unprecedented accuracy of better than 2.8  μ  rad.

  13. Nonlinear and long-term beam dynamics in low energy storage rings

    Science.gov (United States)

    Papash, A. I.; Smirnov, A. V.; Welsch, C. P.

    2013-06-01

    Electrostatic storage rings operate at very low energies in the keV range and have proven to be invaluable tools for atomic and molecular physics. Because of the mass independence of electric rigidity, these machines are able to store a wide range of different particles, from light ions to heavy singly charged biomolecules, opening up unique research opportunities. However, earlier measurements have shown strong limitations in maximum beam intensity, fast decay of the stored ion current, and reduced beam lifetime. The nature of these effects has not been fully understood and an improved understanding of the physical processes influencing beam motion and stability in such rings is needed. In this paper, a comprehensive study into nonlinear and long-term beam dynamics studies is presented on the examples of a number of existing and planned electrostatic storage rings using the BETACOOL, OPERA-3D, and MAD-X simulation software. A detailed investigation into ion kinetics, under consideration of effects from electron cooling and multiple scattering of the beam on a supersonic gas jet target, is carried out and yields a consistent explanation of the physical effects in a whole class of storage rings. The lifetime, equilibrium momentum spread, and equilibrium lateral spread during collisions with the target are estimated. In addition, the results from experiments at the Test Storage Ring, where a low-intensity beam of CF+ ions at 93keV/u has been shrunk to extremely small dimensions, are reproduced. Based on these simulations, the conditions for stable ring operation with an extremely low-emittance beam are presented. Finally, results from studies into the interaction of 3-30 keV ions with a gas jet target are summarized.

  14. Nonlinear and long-term beam dynamics in low energy storage rings

    Directory of Open Access Journals (Sweden)

    A. I. Papash

    2013-06-01

    Full Text Available Electrostatic storage rings operate at very low energies in the keV range and have proven to be invaluable tools for atomic and molecular physics. Because of the mass independence of electric rigidity, these machines are able to store a wide range of different particles, from light ions to heavy singly charged biomolecules, opening up unique research opportunities. However, earlier measurements have shown strong limitations in maximum beam intensity, fast decay of the stored ion current, and reduced beam lifetime. The nature of these effects has not been fully understood and an improved understanding of the physical processes influencing beam motion and stability in such rings is needed. In this paper, a comprehensive study into nonlinear and long-term beam dynamics studies is presented on the examples of a number of existing and planned electrostatic storage rings using the BETACOOL, OPERA-3D, and MAD-X simulation software. A detailed investigation into ion kinetics, under consideration of effects from electron cooling and multiple scattering of the beam on a supersonic gas jet target, is carried out and yields a consistent explanation of the physical effects in a whole class of storage rings. The lifetime, equilibrium momentum spread, and equilibrium lateral spread during collisions with the target are estimated. In addition, the results from experiments at the Test Storage Ring, where a low-intensity beam of CF^{+} ions at 93  keV/u has been shrunk to extremely small dimensions, are reproduced. Based on these simulations, the conditions for stable ring operation with an extremely low-emittance beam are presented. Finally, results from studies into the interaction of 3–30 keV ions with a gas jet target are summarized.

  15. Study of single top production at high energy electron positron colliders

    CERN Document Server

    Garcia, Ignacio; Ros, Eduardo; Vos, Marcel

    2014-01-01

    Top production will play a important role in future high energy electron--positron colliders. Detailed calculations are already available for the process $e^+e^-\\rightarrow t\\bar{t}$, but single top events have mostly been neglected so far. We evaluate the relevance of these events and advocate the exploration of the related process $e^+e^-\\rightarrow W^+bW^-\\bar{b}$.

  16. Experimental studies on the photoelectron instability in the Beijing Electron Positron Collider

    Directory of Open Access Journals (Sweden)

    Z. Y. Guo

    2002-12-01

    Full Text Available A vertical coupled-bunch instability was observed for a positron beam at the Beijing Electron Positron Collider (BEPC. The experimental results show that the instability has similar characteristics as that observed in the Photon Factory of KEK several years ago. The instability at BEPC can be explained by the effect of an electron cloud which is produced in the beam chamber by synchrotron light hitting the wall.

  17. Self-Guiding of Electromagnetic Beams in Degenerate Relativistic Electron-Positron Plasma

    CERN Document Server

    Berezhiani, V I

    2016-01-01

    The possibility of self-trapped propagation of electromagnetic beams in the fully degenerate relativistic electron-positron plasma has been studied applying Fluid-Maxwell model; it is shown that dynamics of such beams can be described by the generalized Nonlinear Schr\\"odinger equation with specific type of saturating nonlinearity. Existence of radially symmetric localized solitary structures is demonstrated. It is found that stable solitary structures exist for the arbitrary level of degeneracy.

  18. Electroweak 2 -> 2 amplitudes for electron-positron annihilation at TeV energies

    CERN Document Server

    Barroso, A; Greco, Mario; Oliveira, S M; Troyan, S I

    2003-01-01

    The non-radiative scattering amplitudes for electron-positron annihilation into quark and lepton pairs in the TeV energy range are calculated in the double-logarithmic approximation. The expressions for the amplitudes are obtained using infrared evolution equations with different cut-offs for virtual photons and for W and Z bosons, and compared with previous results obtained with an universal cut-off.

  19. On a $Z^{\\prime}$ signature at next high energy electron-positron colliders

    CERN Document Server

    Marroquim-Leao de Almeida, F; Martins-Simões, J A; Ramalho, A J; Wulck, S; Do Vale, M A B

    2004-01-01

    The associated production of a $Z^{\\prime}$ and a final hard photon in high energy electron-positron colliders is studied. It is shown that the hard photon spectrum contains useful information on the $Z^{\\prime}$ properties. This remark suggests that, if a new neutral gauge boson exists for $M_{Z^{\\prime}} < \\sqrt{s}$, it will not be necessary to make a new energy run at the $Z^{\\prime}$ mass in order to get most of its properties.

  20. Electroweak corrections to three-jet production in electron-positron annihilation

    CERN Document Server

    Denner, Ansgar; Gehrmann, Thomas; Kurz, Christian

    2009-01-01

    We compute the electroweak ${\\cal O}(\\alpha^3\\alpha_s)$ corrections to three-jet production and related event-shape observables at electron-positron colliders. We properly account for the experimental photon isolation criteria and for the corrections to the total hadronic cross section. Corrections to the three-jet rate and to normalised event-shape distributions turn out to be at the few-per-cent level.

  1. Light-fronts approach to electron-positron pair production in ultrarelativistic heavy-ion collisions

    Energy Technology Data Exchange (ETDEWEB)

    Wells, J.C. [Oak Ridge National Lab., TN (United States). Center for Computational Sciences; Segev, B. [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA (United States). Inst. for Theoretical Atomic and Molecular Physics

    1998-03-01

    The authors solve, in an ultrarelativistic limit, the time-dependent Dirac equation describing electron-positron pair production in peripheral relativistic heavy ion collisions using light front variables and a light-fronts representation, obtaining nonperturbative results for the free pair-creation amplitudes in the collider frame. Their result reproduces the result of second-order perturbation theory in the small charge limit while nonperturbative effects arise for realistic charges of the ions.

  2. Electron/positron measurements obtained with the Mars Science Laboratory Radiation Assessment Detector on the surface of Mars

    Energy Technology Data Exchange (ETDEWEB)

    Koehler, J.; Wimmer-Schweingruber, R.F.; Appel, J. [Kiel Univ. (Germany). Inst. of Experimental and Applied Physics; and others

    2016-04-01

    The Radiation Assessment Detector (RAD), on board the Mars Science Laboratory (MSL) rover Curiosity, measures the energetic charged and neutral particles and the radiation dose rate on the surface of Mars. Although charged and neutral particle spectra have been investigated in detail, the electron and positron spectra have not been investigated yet. The reason for that is that they are difficult to separate from each other and because of the technical challenges involved in extracting energy spectra from the raw data. We use GEANT4 to model the behavior of the RAD instrument for electron/positron measurements.We compare Planetocosmics predictions for different atmospheric pressures and different modulation parameters Φ with the obtained RAD electron/positron measurements.We find that the RAD electron/positron measurements agree well with the spectra predicted by Planetocosmics. Both RAD measurements and Planetocosmics simulation show a dependence of the electron/positron fluxes on both atmospheric pressure and solar modulation potential.

  3. Symplectic orbit and spin tracking code for all-electric storage rings

    Science.gov (United States)

    Talman, Richard M.; Talman, John D.

    2015-07-01

    Proposed methods for measuring the electric dipole moment (EDM) of the proton use an intense, polarized proton beam stored in an all-electric storage ring "trap." At the "magic" kinetic energy of 232.792 MeV, proton spins are "frozen," for example always parallel to the instantaneous particle momentum. Energy deviation from the magic value causes in-plane precession of the spin relative to the momentum. Any nonzero EDM value will cause out-of-plane precession—measuring this precession is the basis for the EDM determination. A proposed implementation of this measurement shows that a proton EDM value of 10-29e -cm or greater will produce a statistically significant, measurable precession after multiply repeated runs, assuming small beam depolarization during 1000 s runs, with high enough precision to test models of the early universe developed to account for the present day particle/antiparticle population imbalance. This paper describes an accelerator simulation code, eteapot, a new component of the Unified Accelerator Libraries (ual), to be used for long term tracking of particle orbits and spins in electric bend accelerators, in order to simulate EDM storage ring experiments. Though qualitatively much like magnetic rings, the nonconstant particle velocity in electric rings gives them significantly different properties, especially in weak focusing rings. Like the earlier code teapot (for magnetic ring simulation) this code performs exact tracking in an idealized (approximate) lattice rather than the more conventional approach, which is approximate tracking in a more nearly exact lattice. The Bargmann-Michel-Telegdi (BMT) equation describing the evolution of spin vectors through idealized bend elements is also solved exactly—original to this paper. Furthermore the idealization permits the code to be exactly symplectic (with no artificial "symplectification"). Any residual spurious damping or antidamping is sufficiently small to permit reliable tracking for the

  4. Experimental modelling of the dipole magnet for the electron storage ring DELSY

    CERN Document Server

    Meshkov, I N; Syresin, E M

    2003-01-01

    In the Joint Institute for Nuclear Research (Dubna) the project of Dubna Electron Synchrotron (DELSY) with an electron energy of 1.2 GeV is developed. The electron storage ring in the DELSY project is planned to be created on the basis of magnetic elements, which were used earlier in the storage ring AmPS (NIKHEF, Amsterdam). The optics of the ring is necessary to be changed, its perimeter to be reduced approximately in one and a half time, the energy of electrons to be increased. The paper is devoted to the development of a modified dipole magnet of the storage ring. The preliminary estimation of geometry of the magnet pole is carried out by means of computer modelling using two- and three- dimensional codes of the magnetic field calculation SUPERFISH and RADIA. The experimental stand for the measurements of the dipole magnetic field is described. As the result of calculational and experimental modelling for the dipole magnet, the geometry of its poles was estimated, providing in the horizontal aperture +- 3...

  5. Effectiveness of rf phase modulation for increasing bunch length in electron storage rings

    Science.gov (United States)

    Orsini; Mosnier

    2000-04-01

    Aiming at increasing the apparent bunch length and hence the beam lifetime in electron storage rings, rf phase modulation near one parametric resonance has been experimentally investigated. Since the possible benefit of this technique depends greatly on the ring parameters, we studied the effect of such a modulation for different rf parameters on the longitudinal emittance. Theoretical predictions and results of simulations are compared and discussed. It is shown that synchrotron radiation tends to spoil the parametric resonance. In particular, a criterion for island survival has been found.

  6. Calibration of the Nonlinear Accelerator Model at the Diamond Storage Ring

    CERN Document Server

    Bartolini, Riccardo; Rowland, James; Martin, Ian; Schmidt, Frank

    2010-01-01

    The correct implementation of the nonlinear ring model is crucial to achieve the top performance of a synchrotron light source. Several dynamics quantities can be used to compare the real machine with the model and eventually to correct the accelerator. Most of these methods are based on the analysis of turn-by-turn data of excited betatron oscillations. We present the experimental results of the campaign of measurements carried out at the Diamond. A combination of Frequency Map Analysis (FMA) and detuning with momentum measurements has allowed a precise calibration of the nonlinear model capable of reproducing the nonlinear beam dynamics in the storage ring

  7. First storage of ion beams in the Double Electrostatic Ion-Ring Experiment: DESIREE

    Energy Technology Data Exchange (ETDEWEB)

    Schmidt, H. T.; Thomas, R. D.; Gatchell, M.; Rosen, S.; Reinhed, P.; Loefgren, P.; Braennholm, L.; Blom, M.; Bjoerkhage, M.; Baeckstroem, E.; Alexander, J. D.; Leontein, S.; Zettergren, H.; Liljeby, L.; Kaellberg, A.; Simonsson, A.; Hellberg, F.; Mannervik, S.; Larsson, M.; Geppert, W. D. [Department of Physics, Stockholm University, SE-10691 Stockholm (Sweden); and others

    2013-05-15

    We report on the first storage of ion beams in the Double ElectroStatic Ion Ring ExpEriment, DESIREE, at Stockholm University. We have produced beams of atomic carbon anions and small carbon anion molecules (C{sub n}{sup -}, n= 1, 2, 3, 4) in a sputter ion source. The ion beams were accelerated to 10 keV kinetic energy and stored in an electrostatic ion storage ring enclosed in a vacuum chamber at 13 K. For 10 keV C{sub 2}{sup -} molecular anions we measure the residual-gas limited beam storage lifetime to be 448 s {+-} 18 s with two independent detector systems. Using the measured storage lifetimes we estimate that the residual gas pressure is in the 10{sup -14} mbar range. When high current ion beams are injected, the number of stored particles does not follow a single exponential decay law as would be expected for stored particles lost solely due to electron detachment in collision with the residual-gas. Instead, we observe a faster initial decay rate, which we ascribe to the effect of the space charge of the ion beam on the storage capacity.

  8. Energy Materials Center at Cornell: Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Abruña, Héctor [Cornell Univ., Ithaca, NY (United States); Mutolo, Paul F [Cornell Univ., Ithaca, NY (United States)

    2015-01-02

    The mission of the Energy Materials Center at Cornell (emc2) was to achieve a detailed understanding, via a combination of synthesis of new materials, experimental and computational approaches, of how the nature, structure, and dynamics of nanostructured interfaces affect energy conversion and storage with emphasis on fuel cells, batteries and supercapacitors. Our research on these systems was organized around a full system strategy for; the development and improved performance of materials for both electrodes at which storage or conversion occurs; understanding their internal interfaces, such as SEI layers in batteries and electrocatalyst supports in fuel cells, and methods for structuring them to enable high mass transport as well as high ionic and electronic conductivity; development of ion-conducting electrolytes for batteries and fuel cells (separately) and other separator components, as needed; and development of methods for the characterization of these systems under operating conditions (operando methods) Generally, our work took industry and DOE report findings of current materials as a point of departure to focus on novel material sets for improved performance. In addition, some of our work focused on studying existing materials, for example observing battery solvent degradation, fuel cell catalyst coarsening or monitoring lithium dendrite growth, employing in operando methods developed within the center.

  9. Improved nonlinear optimization in the storage ring of the modern synchrotron radiation light source

    Institute of Scientific and Technical Information of China (English)

    TIAN Shun-Qiang; LIU Gui-Min; HOU Jie; CHEN Guang-Ling; CHEN Sen-Yu

    2009-01-01

    In the storage ring of the third generation light sources,nonlinear optimization is an indispensable course in order to obtain ample dynamic acceptances and to reach high injection efficiency and long beam lifetime,especially in a low emittance lattice.An improved optimization algorithm based on the single resonance approach,which takes relative weight and initial Harmonic Sextupole Integral Strength (HSIS) as search variables,is discussed in this paper.Applications of the improved method in several test lattices are presented.Detailed analysis of the storage ring of the Shanghai Synchrotron Radiation Facility (SSRF) is particularly emphasized.Furthermore,cancellation of the driving terms is investigated to reveal the physical mechanism of the harmonic sextupole compensation.Sensitivity to the weight and the initial HSIS as well as dependence of the optimum solution on the convergent factor is analyzed.

  10. Study of Magnetic Hysteresis Effects in a Storage Ring Using Precision Tune Measurement

    CERN Document Server

    Li, Wei; Mikhailov, Stepan F; Xu, Wei; Li, Jing-Yi; Li, Wei-Min; Wu, Ying K

    2016-01-01

    With advances in accelerator science and technology in the recent decades, the accelerator community has focused on the development of next-generation light sources, for example the diffraction-limited storage rings (DLSRs), which requires precision control of the electron beam energy and betatron tunes. This work is aimed at understanding magnet hysteresis effects on the electron beam energy and lattice focusing in the circular accelerators, and developing new methods to gain better control of these effects. In this paper, we will report our recent experimental study of the magnetic hysteresis effects and their impacts on the Duke storage ring lattice using the transverse feedback based precision tune measurement system. The major magnet hysteresis effects associated with magnet normalization and lattice ramping are carefully studied to determine an effective procedure for lattice preparation while maintaining a high degree of reproducibility of lattice focusing. The local hysteresis effects are also studied...

  11. Applications of differential algebra to single-particle dynamics in storage rings

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Y.

    1991-09-01

    Recent developments in the use of differential algebra to study single-particle beam dynamics in charged-particle storage rings are the subject of this paper. Chapter 2 gives a brief review of storage rings. The concepts of betatron motion and synchrotron motion, and their associated resonances, are introduced. Also introduced are the concepts of imperfections, such as off-momentum, misalignment, and random and systematic errors, and their associated corrections. The chapter concludes with a discussion of numerical simulation principles and the concept of one-turn periodic maps. In Chapter 3, the discussion becomes more focused with the introduction of differential algebras. The most critical test for differential algebraic mapping techniques -- their application to long-term stability studies -- is discussed in Chapter 4. Chapter 5 presents a discussion of differential algebraic treatment of dispersed betatron motion. The paper concludes in Chapter 6 with a discussion of parameterization of high-order maps.

  12. Beam dynamics simulations in laser electron storage rings and optical stochastic cooling

    Science.gov (United States)

    Duru, Alper

    Laser-electron storage rings are potential compact X-ray sources. Longitudinal dynamics in laser-electron storage rings is studied including the effects of both laser interaction and synchrotron radiation. It is shown that the steady state energy spread can reach as high as a few percent. The main reason is the wide spread in the energy loss by electrons to laser photons. Optical stochastic cooling has been studied numerically. The effects of the finite bandwidth of the amplifier are mixing and signal distortion. Both are included in the simulations and the results are compared to theoretical results. It is shown that the beam can be cooled both in transverse and longitudinal phase phase spaces simultaneously.

  13. Beam Performance and Luminosity Limitations in the High-Energy Storage Ring (HESR)

    CERN Document Server

    Lehrach, A; Hinterberger, F; Maier, R; Prasuhn, D

    2006-01-01

    The High-Energy Storage Ring (HESR) of the future International Facility for Antiproton and Ion Research (FAIR) at GSI in Darmstadt is planned as an antiproton synchrotron and storage ring in the momentum range from 1.5 to 15 GeV/c. An important feature of this new facility is the combination of phase space cooled beams with dense internal targets (e.g. pellet targets), resulting in demanding beam parameter of two operation modes: high luminosity mode with peak luminosities up to 2*10^32 cm-2 s-1, and high resolution mode with a momentum spread down to 10^-5, respectively. To reach these beam parameters very powerful phase space cooling is needed, utilizing high-energy electron cooling and high-bandwidth stochastic cooling. The effect of beam-target scattering and intra-beam interaction is investigated in order to study beam equilibria and beam losses for the two different operation modes.

  14. Beam performance and luminosity limitations in the high-energy storage ring (HESR)

    Science.gov (United States)

    Lehrach, A.; Boine-Frankenheim, O.; Hinterberger, F.; Maier, R.; Prasuhn, D.

    2006-06-01

    The high-energy storage ring (HESR) of the future International Facility for Antiproton and Ion Research (FAIR) at GSI in Darmstadt is planned as an antiproton synchrotron storage ring in the momentum range 1.5-15 GeV/ c. An important feature of this new facility is the combination of phase space cooled beams and dense internal targets (e.g. pellet targets), which results in demanding beam parameter requirements for two operation modes: high luminosity mode with peak luminosities to 2×10 32 cm -2 s -1, and high-resolution mode with a momentum spread down to 10 -5. To reach these beam parameters one needs a very powerful phase space cooling, utilizing high-energy electron cooling and high-bandwidth stochastic cooling. The effects of beam-target scattering and intra-beam interaction are investigated in order to study beam equilibria and beam losses for the two different operation modes.

  15. Recombination and Ionization Measurements at the Heidelberg Heavy Ion Storage Ring TSR

    Science.gov (United States)

    Hahn, M.; Lestinsky, M.; Novotný, O.; Savin, D. W.; Bernhardt, D.; Müller, A.; Schippers, S.; Krantz, C.; Grieser, M.; Repnow, R.; Wolf, A.

    2011-05-01

    Knowledge of the charge state distribution (CSD) of astrophysical plasmas is important for the interpretation of spectroscopic data. To accurately calculate CSDs, reliable rate coefficients are needed for dielectronic recombination (DR), which is the dominant electron-ion recombination mechanism for most ions, and for electron impact ionization (EII). We are carrying out DR and EII measurements of astrophysically important ions using the TSR storage ring at the Max-Plank-Institute for Nuclear Physics in Heidelberg, Germany. Storage ring measurements are largely free of the metastable contamination found in other experimental geometries, resulting in more unambiguous DR and EII reaction rate measurements. The measured data can be used in plasma modelling as well as for benchmarking theoretical atomic calculations.

  16. A modeling GUI for accelerator physics of the storage ring at SSRF

    Institute of Scientific and Technical Information of China (English)

    CHEN Guangling; TIAN Shunqiang; LIU Guimin; JIANG Bocheng

    2009-01-01

    In this paper, we report a MATLAB-based GUI tool, bodgui, which integrates functions of lattice editor,linear match, and nonlinear optimization, and visualized tracking functions for beam optics design. A user can switch his/ber design procedures one to another. Flexibilities are provided for adjusting or optimizing the lattice settings in commissioning or operation of the accelerators. The algorithm of the linear match and nonlinear optimization, and the GUI windows including the main functions and running status, are presented. The SSRF storage ring was employed as a test lattice. Several optics modes designed and optimized by the GUI tools were used for commissioning the storage ring. Functions of bodgui tool are machine-independent, and it can be well applied to modern light sources being built in other parts of the world.

  17. Measurement of the Beam Longitudinal Profile in a Storage Ring by Non-Linear Laser Mixing

    Science.gov (United States)

    Beche, J.-F.; Byrd, J.; De Santis, S.; Denes, P.; Placidi, M.; Turner, W.; Zolotorev, M.

    2004-11-01

    We report on the development of a new technique for the measurement of the longitudinal beam profile in storage rings. This technique, which has been successfully demonstrated at the Advanced Light Source, mixes the synchrotron radiation with the light from a mode-locked solid-state laser oscillator in a non-linear crystal. The up-converted radiation is then detected with a photomultiplier and processed to extract, store, and display the required information. The available choices of laser repetition frequency, pulse width, and phase modulation give a wide range of options for matching the bunch configuration of a particular storage ring. Besides the dynamic measurement of the longitudinal profile of each bunch, the instrument can monitor the evolution of the bunch tails, the presence of un trapped particles, and their diffusion into nominally empty RF buckets ("ghost bunches").

  18. Measurement of the beam longitudinal profile in a storage ring bynon-linear laser mixing

    Energy Technology Data Exchange (ETDEWEB)

    Beche, J.-F.; Byrd, J.; De Santis, S.; Denes, P.; Placidi, M.; Turner, W.; Zolotorev, M.

    2004-05-03

    We report on the development of a new technique for the measurement of the longitudinal beam profile in storage rings. This technique, which has been successfully demonstrated at the Advanced Light Source, mixes the synchrotron radiation with the light from a mode-locked solid state laser oscillator in a non-linear crystal. The up-converted radiation is then detected with a photomultiplier and processed to extract, store, and display the required information. The available choices of laser repetition frequency, pulse width, and phase modulation give a wide range of options for matching the bunch configuration of a particular storage ring. Besides the dynamic measurement of the longitudinal profile of each bunch, the instrument can monitor the evolution of the bunch tails, the presence of untrapped particles and their diffusion into nominally empty RF buckets (''ghostbunches'').

  19. Ion Optics of the HESR storage ring at FAIR for operation with heavy ions

    Energy Technology Data Exchange (ETDEWEB)

    Kovalenko, Oleksandr; Dolinskyy, Oleksiy; Litvinov, Yuri; Stoehlker, Thomas [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, Darmstadt (Germany)

    2014-07-01

    High Energy Storage Ring (HESR) of the FAIR project is primarily designed for internal target experiments with stored and cooled antiprotons, which is the main objective of the PANDA collaboration. However, the HESR storage ring also appears to have remarkable properties to carry out physics experiments with heavy ions. This paper proposes a new ion optical design allowing for the heavy ion operation mode of the HESR. The main goal was to provide an optics which meets the requirements of the future experiments with heavy ion beams. In connection, issues like closed orbit correction, dynamic aperture as well as other characteristics of beam dynamics of the new ion optical setup are under analysis in this study.

  20. Steady-State Microbunching in a Storage Ring for Generating Coherent Radiation

    Energy Technology Data Exchange (ETDEWEB)

    Ratner, Daniel F.; /Stanford U., Appl. Phys. Dept.; Chao, Alexander W.; /SLAC

    2011-05-19

    Synchrotrons and storage rings deliver radiation across the electromagnetic spectrum at high repetition rates, and free electron lasers (FELs) produce radiation pulses with high peak brightness. However, at present few light sources can generate both high repetition rate and high brightness outside the optical range. We propose to create steady-state microbunching (SSMB) in a storage ring to produce coherent radiation at a high repetition rate or in continuous wave (CW) mode. In this paper we describe a general mechanism for producing SSMB and give sample parameters for EUV lithography and sub-millimeter sources. We also describe a similar arrangement to produce two pulses with variable spacing for pump-probe experiments. With technological advances, SSMB could reach the soft X-ray range (< 10 nm).

  1. Photo excitation and laser detachment of C60 − anions in a storage ring

    DEFF Research Database (Denmark)

    Støchkel, Kristian; Andersen, Jens Ulrik

    2013-01-01

    (REMPED) has been repeated both at room temperature and with the trap cooled to liquid nitrogen temperature. However, wavelength dependence of the overlap of the strongly focused laser beam with the ion beam introduces distortions of the absorption spectrum. We have therefore applied a new method...... level, is much weaker in the new measurements and could be an H g vibrational sideband. Also earlier studies of direct laser detachment from C60 − in the storage ring ASTRID have been revisited, with ions cooled by liquid nitrogen in the ion trap. We confirm the previous measurement with a determination......We have studied the photo physics of C60 − anions in the electrostatic storage ring ELISA with ions produced in a plasma source and cooled and bunched in a He filled ion trap. A previous study using delayed electron detachment as a signal of resonance-enhanced multiphoton electron detachment...

  2. Intense inverse compton {gamma}-ray source from Duke storage ring FEL

    Energy Technology Data Exchange (ETDEWEB)

    Litvinenko, V.N.; Madey, J.M.J. [Duke Univ., Durham, NC (United States)

    1995-12-31

    We suggest using FEL intracavity power in the Duke storage ring fortrays production via Inverse Compton Backscattering (ICB). The OK-4 FEL driven by the Duke storage ring will tens of watts of average lasing power in the UV/VUV range. Average intracavity power will be in kilowatt range and can be used to pump ICB source. The {gamma}-rays with maximum energy from 40 MeV to 200 MeV with intensity of 0.1-5 10{sup 10}{gamma} per second can be generated. In this paper we present expected parameters of {gamma}-ray beam parameters including its intensity and distribution. We discuss influence of e-beam parameters on collimated {gamma}-rays spectrum and optimization of photon-electron interaction point.

  3. Magnetic Measurements of Storage Ring Magnets for the APS Upgrade Project

    Energy Technology Data Exchange (ETDEWEB)

    Doose, C.; Dejus, R.; Jaski, M.; Jansma, W.; Collins, J.; Donnelly, A.; Liu, J.; Cease, H.; Decker, G.; Jain, A.; DiMarco, J.

    2017-06-01

    Extensive prototyping of storage ring magnets is ongoing at the Advanced Photon Source (APS) in support of the APS Multi-Bend Achromat (MBA) upgrade project (APS-U) [1]. As part of the R&D activities four quadrupole magnets with slightly different geometries and pole tip materials, and one sextupole magnet with vanadium permendur (VP) pole tips were designed, built and tested. Magnets were measured individually using a rotating coil and a Hall probe for detailed mapping of the magnetic field. Magnets were then assembled and aligned relative to each other on a steel support plate and concrete plinth using precision machined surfaces to gain experience with the alignment method chosen for the APS-U storage ring magnets. The required alignment of magnets on a common support structure is 30 μm rms. Measurements of magnetic field quality, strength and magnet alignment after subjecting the magnets and assemblies to different tests are presented.

  4. A storage ring experiment to detect a proton electric dipole moment

    Energy Technology Data Exchange (ETDEWEB)

    Anastassopoulos, V. [Department of Physics, University of Patras, 26500 Rio-Patras, Greece; Andrianov, S. [Faculty of Applied Mathematics and Control Processes, Saint-Petersburg State University, Saint-Petersburg, Russia; Baartman, R. [TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia V6T2A3, Canada; Baessler, S. [Department of Physics, University of Virginia, Charlottesville, Virginia 22904, USA; Bai, M. [Institut für Kernphysik and JARA-Fame, Forschungszentrum Jülich, 52425 Jülich, Germany; Benante, J. [Brookhaven National Laboratory, Upton, New York 11973, USA; Berz, M. [Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824, USA; Blaskiewicz, M. [Brookhaven National Laboratory, Upton, New York 11973, USA; Bowcock, T. [Department of Physics, University of Liverpool, Liverpool, United Kingdom; Brown, K. [Brookhaven National Laboratory, Upton, New York 11973, USA; Casey, B. [Fermi National Accelerator Laboratory, Batavia, Illinois 60510, USA; Conte, M. [Physics Department and INFN Section of Genoa, 16146 Genoa, Italy; Crnkovic, J. D. [Brookhaven National Laboratory, Upton, New York 11973, USA; D’Imperio, N. [Brookhaven National Laboratory, Upton, New York 11973, USA; Fanourakis, G. [Institute of Nuclear and Particle Physics NCSR Demokritos, GR-15310 Aghia Paraskevi Athens, Greece; Fedotov, A. [Brookhaven National Laboratory, Upton, New York 11973, USA; Fierlinger, P. [Technical University München, Physikdepartment and Excellence-Cluster “Universe,” Garching, Germany; Fischer, W. [Brookhaven National Laboratory, Upton, New York 11973, USA; Gaisser, M. O. [Center for Axion and Precision Physics Research, Institute for Basic Science (IBS), Daejeon 34141, South Korea; Giomataris, Y. [CEA/Saclay, DAPNIA, 91191 Gif-sur-Yvette Cedex, France; Grosse-Perdekamp, M. [Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA; Guidoboni, G. [University of Ferrara, INFN of Ferrara, Ferrara, Italy; Hacıömeroğlu, S. [Center for Axion and Precision Physics Research, Institute for Basic Science (IBS), Daejeon 34141, South Korea; Hoffstaetter, G. [Laboratory for Elementary-Particle Physics, Cornell University, Ithaca, New York 14853, USA; Huang, H. [Brookhaven National Laboratory, Upton, New York 11973, USA; Incagli, M. [Physics Department, University and INFN Pisa, Pisa, Italy; Ivanov, A. [Faculty of Applied Mathematics and Control Processes, Saint-Petersburg State University, Saint-Petersburg, Russia; Kawall, D. [Department of Physics, University of Massachusetts, Amherst, Massachusetts 01003, USA; Kim, Y. I. [Center for Axion and Precision Physics Research, Institute for Basic Science (IBS), Daejeon 34141, South Korea; King, B. [Department of Physics, University of Liverpool, Liverpool, United Kingdom; Koop, I. A. [Budker Institute of Nuclear Physics, 630090 Novosibirsk, Russia; Lazarus, D. M. [Brookhaven National Laboratory, Upton, New York 11973, USA; Lebedev, V. [Fermi National Accelerator Laboratory, Batavia, Illinois 60510, USA; Lee, M. J. [Center for Axion and Precision Physics Research, Institute for Basic Science (IBS), Daejeon 34141, South Korea; Lee, S. [Center for Axion and Precision Physics Research, Institute for Basic Science (IBS), Daejeon 34141, South Korea; Lee, Y. H. [Korea Research Institute of Standards and Science, Daejeon 34141, South Korea; Lehrach, A. [Institut für Kernphysik and JARA-Fame, Forschungszentrum Jülich, 52425 Jülich, Germany; RWTH Aachen University and JARA-Fame, III. Physikalisches Institut B, Physikzentrum, 52056 Aachen, Germany; Lenisa, P. [University of Ferrara, INFN of Ferrara, Ferrara, Italy; Levi Sandri, P. [Laboratori Nazionali di Frascati, INFN, I-00044 Frascati, Rome, Italy; Luccio, A. U. [Brookhaven National Laboratory, Upton, New York 11973, USA; Lyapin, A. [Royal Holloway, University of London, Egham, Surrey, United Kingdom; MacKay, W. [Brookhaven National Laboratory, Upton, New York 11973, USA; Maier, R. [Institut für Kernphysik and JARA-Fame, Forschungszentrum Jülich, 52425 Jülich, Germany

    2016-11-01

    A new experiment is described to detect a permanent electric dipole moment of the proton with a sensitivity of $10^{-29}e\\cdot$cm by using polarized "magic" momentum $0.7$~GeV/c protons in an all-electric storage ring. Systematic errors relevant to the experiment are discussed and techniques to address them are presented. The measurement is sensitive to new physics beyond the Standard Model at the scale of 3000~TeV.

  5. Cascade Problems in Some Atomic Lifetime Measurements at a Heavy-Ion Storage Ring

    Energy Technology Data Exchange (ETDEWEB)

    Trabert, E; Hoffmann, J; Krantz, C; Wolf, A; Ishikawa, Y; Santana, J

    2008-10-09

    Lifetimes of 3s{sup 2}3p{sup k} ground configuration levels of Al-, Si-, P-, and S-like ions of Be, Co, and Ni have been measured at a heavy-ion storage ring. Some of the observed decay curves show strong evidence of cascade repopulation from specific 3d levels that feature lifetimes in the same multi-millisecond range as the levels of the ground configuration.

  6. Design summary of the magnet support structures for the proton storage ring injection line upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Bernardin, J.D.; Ledford, J.E.; Smith, B.G.

    1997-05-01

    This report summarizes the technical engineering and design issues associated with the Proton Storage Ring (PSR) Injection Line upgrade of the Los Alamos Neutron Science Center (LANSCE). The main focus is on the engineering design calculations of several magnet support structures. The general procedure based upon a set number of design criteria is outlined, followed by a case-by-case summary of the engineering design analyses, reutilization or fabrication callouts and design safety factors.

  7. A Storage Ring Experiment to Detect a Proton Electric Dipole Moment

    CERN Document Server

    Anastassopoulos, V; Baartman, R; Bai, M; Baessler, S; Benante, J; Berz, M; Blaskiewicz, M; Bowcock, T; Brown, K; Casey, B; Conte, M; Crnkovic, J; Fanourakis, G; Fedotov, A; Fierlinger, P; Fischer, W; Gaisser, M O; Giomataris, Y; Grosse-Perdekamp, M; Guidoboni, G; Haciomeroglu, S; Hoffstaetter, G; Huang, H; Incagli, M; Ivanov, A; Kawall, D; Khazin, B; Kim, Y I; King, B; Koop, I A; Larsen, R; Lazarus, D M; Lebedev, V; Lee, M J; Lee, S; Lee, Y H; Lehrach, A; Lenisa, P; Sandri, P Levi; Luccio, A U; Lyapin, A; MacKay, W; Maier, R; Makino, K; Malitsky, N; Marciano, W J; Meng, W; Meot, F; Metodiev, E M; Miceli, L; Moricciani, D; Morse, W M; Nagaitsev, S; Nayak, S K; Orlov, Y F; Ozben, C S; Park, S T; Pesce, A; Pile, P; Polychronakos, V; Podobedov, B; Pretz, J; Ptitsyn, V; Ramberg, E; Raparia, D; Rathmann, F; Rescia, S; Roser, T; Sayed, H Kamal; Semertzidis, Y K; Senichev, Y; Sidorin, A; Silenko, A; Simos, N; Stahl, A; Stephenson, E J; Stroeher, H; Syphers, M J; Talman, J; Talman, R M; Tishchenko, V; Touramanis, C; Tsoupas, N; Venanzoni, G; Vetter, K; Vlassis, S; Won, E; Zavattini, G; Zelenski, A; Zioutas, K

    2015-01-01

    A new experiment is described to detect a permanent electric dipole moment of the proton with a sensitivity of $10^{-29}e\\cdot$cm by using polarized "magic" momentum $0.7$~GeV/c protons in an all-electric storage ring. Systematic errors relevant to the experiment are discussed and techniques to address them are presented. The measurement is sensitive to new physics beyond the Standard Model at the scale of 3000~TeV.

  8. A storage ring experiment to detect a proton electric dipole moment.

    Science.gov (United States)

    Anastassopoulos, V; Andrianov, S; Baartman, R; Baessler, S; Bai, M; Benante, J; Berz, M; Blaskiewicz, M; Bowcock, T; Brown, K; Casey, B; Conte, M; Crnkovic, J D; D'Imperio, N; Fanourakis, G; Fedotov, A; Fierlinger, P; Fischer, W; Gaisser, M O; Giomataris, Y; Grosse-Perdekamp, M; Guidoboni, G; Hacıömeroğlu, S; Hoffstaetter, G; Huang, H; Incagli, M; Ivanov, A; Kawall, D; Kim, Y I; King, B; Koop, I A; Lazarus, D M; Lebedev, V; Lee, M J; Lee, S; Lee, Y H; Lehrach, A; Lenisa, P; Levi Sandri, P; Luccio, A U; Lyapin, A; MacKay, W; Maier, R; Makino, K; Malitsky, N; Marciano, W J; Meng, W; Meot, F; Metodiev, E M; Miceli, L; Moricciani, D; Morse, W M; Nagaitsev, S; Nayak, S K; Orlov, Y F; Ozben, C S; Park, S T; Pesce, A; Petrakou, E; Pile, P; Podobedov, B; Polychronakos, V; Pretz, J; Ptitsyn, V; Ramberg, E; Raparia, D; Rathmann, F; Rescia, S; Roser, T; Kamal Sayed, H; Semertzidis, Y K; Senichev, Y; Sidorin, A; Silenko, A; Simos, N; Stahl, A; Stephenson, E J; Ströher, H; Syphers, M J; Talman, J; Talman, R M; Tishchenko, V; Touramanis, C; Tsoupas, N; Venanzoni, G; Vetter, K; Vlassis, S; Won, E; Zavattini, G; Zelenski, A; Zioutas, K

    2016-11-01

    A new experiment is described to detect a permanent electric dipole moment of the proton with a sensitivity of 10(-29) e ⋅ cm by using polarized "magic" momentum 0.7 GeV/c protons in an all-electric storage ring. Systematic errors relevant to the experiment are discussed and techniques to address them are presented. The measurement is sensitive to new physics beyond the standard model at the scale of 3000 TeV.

  9. Analysis of multi-bunch instabilities at the diamond storage ring

    CERN Document Server

    Bartolini, Riccardo; Rehm, Guenther; Smaluk, Victor

    2017-01-01

    We present the result of the analytical, numerical and experimental analysis of multi-bunch instabilities at the Diamond storage ring. This work compares the impedance estimates with CST with the analysis of the growth rates of the excited multi-bunch modes in different machine configurations. The contribution of a number of wakefield sources has been identified with very high precision thanks to high quality data provided by the existing TMBF diagnostics.

  10. Dynamical aspects on FEL interaction in single passage and storage ring devices

    Energy Technology Data Exchange (ETDEWEB)

    Dattoli, G.; Renieri, A. [ENEA, Frascati (Italy)

    1995-12-31

    The dynamical behaviour of the free-electron lasers is investigated using appropriate scaling relations valid for devices operating in the low and high gain regimes, including saturation. The analysis is applied to both single passage and storage ring configurations. In the latter case the interplay between the interaction of the electron bean with the laser field and with the accelerator environment is investigated. In particular we discuss the effect of FEL interaction on the microwave instability.

  11. Analytical Benchmarking, Precision Particle Tracking, Electric and Magnetic Storage Rings, Runge-Kutta, Predictor-Corrector

    CERN Document Server

    Metodiev, E M; Fandaros, M; Haciomeroglu, S; Huang, D; Huang, K L; Patil, A; Prodromou, R; Semertzidis, O A; Sharma, D; Stamatakis, A N; Orlov, Y F; Semertzidis, Y K

    2015-01-01

    A set of analytical benchmarks for tracking programs are required for precision storage ring experiments. To determine the accuracy of precision tracking programs in electric and magnetic rings, a variety of analytical estimates of particle and spin dynamics in the rings are developed and compared to the numerical results of tracking simulations. Initial discrepancies in the comparisons indicated the need for improvement of several of the analytical estimates. As an example, we find that the fourth order Runge-Kutta/Predictor-Corrector method was accurate but slow, and that it passed all the benchmarks it was tested against, often to the sub-part per billion level. Thus high precision analytical estimates and tracking programs based on fourth order Runge-Kutta/Predictor-Corrector integration can be used to benchmark faster tracking programs for accuracy.

  12. Spin decoherence in electron storage rings. More from a simple model

    Energy Technology Data Exchange (ETDEWEB)

    Barber, D.P. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Heinemann, K. [The Univ. of New Mexico, Albuquerque, NM (United States). Dept. of Mathematics and Statistics

    2015-06-15

    This is an addendum to the paper ''Some models of spin coherence and decoherence in storage rings'' by one of the authors (K. Heinemann, DESY Report 97-166 (1997)), in which spin diffusion in simple electron storage rings is studied. In particular, we illustrate in a compact way, namely that the exact formalism of this article delivers a rate of depolarisation which can differ from that obtained by the conventional treatments of spin diffusion which rely on the use of the derivative ∂n/∂η. As a vehicle we consider a ring with a Siberian Snake and electron polarisation in the plane of the ring. For this simple setup with its one-dimensional spin motion, we avoid having to deal directly with the Bloch equation for the polarisation density. Our treatment, which is deliberately pedagogical, shows that the use of ∂n/∂η provides a very good approximation to the rate of spin depolarisation in the model considered. But it then shows that the exact rate of depolarisation can be obtained by replacing ∂n/∂η by another derivative, while giving a heuristic justification for the new derivative.

  13. Single bunch injection system for storage ring FEL using an rf photoinjector

    Science.gov (United States)

    O'Shea, P. G.; Lancaster, J. A.; Madey, J. M. J.; Sachtschale, R.; Jones, R.

    1997-05-01

    RF photoinjectors have gained acceptance as the source of choice for high-brightness electron accelerators, but have been quite expensive to build and difficult to operate. In this paper we describe the successful operation of an inexpensive, simple and reliable rf photoinjector suitable for single bunch injection into storage rings. For optimum storage ring FEL and Compton Backscatter performance, we require that the electrons be injected to specified ring rf buckets and no others. The injector-linac electron gun is a single-cell s-band rf gun with a LaB6 cathode. The gun is followed by an a-magnet momentum filter and buncher. The LaB6 cathode can be operated in a pure thermionic mode, a laser switched photoemission mode, or in a combined mode. The laser is a near-UV TEA nitrogen laser with a 600 ps pulse, and 0-50 Hz repetition rate. We routinely inject 0.1 nC bunches at 270 MeV. The ratio of charge in the primary ring bucket to that in the other buckets is better than 1000.

  14. Spin decoherence in electron storage rings --- more from a simple model

    CERN Document Server

    Barber, D P

    2015-01-01

    This is an addendum to the paper "Some models of spin coherence and decoherence in storage rings" by one of the authors [1] in which spin diffusion in simple electron storage rings is studied. In particular, we illustrate in a compact way, a key implication in the Epilogue of [1], namely that the exact formalism of [1] delivers a rate of depolarisation which can differ from that obtained by the conventional treatments of spin diffusion which rely on the use of the derivative $\\partial \\hat n/\\partial\\eta$ [2,3,4]. As a vehicle we consider a ring with a Siberian Snake and electron polarisation in the plane of the ring (Machine II in [1]). For this simple setup with its one-dimensional spin motion, we avoid having to deal directly with the Bloch equation [5,6] for the polarisation density. Our treatment, which is deliberately pedagogical, shows that the use of $\\partial \\hat n/\\partial\\eta$ provides a very good approximation to the rate of spin depolarisation in the model considered. But it then shows that the ...

  15. Photoswitchable Dihydroazulene Macrocycles for Solar Energy Storage: The Effects of Ring Strain.

    Science.gov (United States)

    Vlasceanu, Alexandru; Frandsen, Benjamin N; Skov, Anders B; Hansen, Anne Schou; Rasmussen, Mads Georg; Kjaergaard, Henrik G; Mikkelsen, Kurt V; Nielsen, Mogens Brøndsted

    2017-09-11

    Efficient energy storage and release are two major challenges of solar energy harvesting technologies. The development of molecular solar thermal systems presents one approach to address these issues by tuning the isomerization reactions of photo/thermoswitches. Here we show that the incorporation of photoswitches into macrocyclic structures is a particularly attractive solution for increasing the storage time. We present the synthesis and properties of a series of macrocycles incorporating two dihydroazulene (DHA) photoswitching subunits, bridged by linkers of varying chain length. Independent of ring size, all macrocycles exhibit stepwise, light-induced, ring-opening reactions (DHA-DHA to DHA-VHF to VHF-VHF; VHF = vinylheptafulvene) with the first DHA undergoing isomerization with a similar efficiency as the uncyclized parent system while the second (DHA-VHF to VHF-VHF) is significantly slower. The energy-releasing, VHF-to-DHA, ring closures also occur in a stepwise manner and are systematically found to proceed slower in the more strained (smaller) cycles, but in all cases with a remarkably slow conversion of the second VHF to DHA. We managed to increase the half-life of the second VHF-to-DHA conversion from 65 to 202 h at room temperature by simply decreasing the ring size. A computational study reveals the smallest macrocycle to have the most energetic VHF-VHF state and hence highest energy density.

  16. Accurate correction of magnetic field instabilities for high-resolution isochronous mass measurements in storage rings

    CERN Document Server

    Shuai, P; Zhang, Y H; Litvinov, Yu A; Wang, M; Tu, X L; Blaum, K; Zhou, X H; Yuan, Y J; Audi, G; Yan, X L; Chen, X C; Xu, X; Zhang, W; Sun, B H; Yamaguchi, T; Chen, R J; Fu, C Y; Ge, Z; Huang, W J; Liu, D W; Xing, Y M; Zeng, Q

    2014-01-01

    Isochronous mass spectrometry (IMS) in storage rings is a successful technique for accurate mass measurements of short-lived nuclides with relative precision of about $10^{-5}-10^{-7}$. Instabilities of the magnetic fields in storage rings are one of the major contributions limiting the achievable mass resolving power, which is directly related to the precision of the obtained mass values. A new data analysis method is proposed allowing one to minimise the effect of such instabilities. The masses of the previously measured at the CSRe $^{41}$Ti, $^{43}$V, $^{47}$Mn, $^{49}$Fe, $^{53}$Ni and $^{55}$Cu nuclides were re-determined with this method. An improvement of the mass precision by a factor of $\\sim 1.7$ has been achieved for $^{41}$Ti and $^{43}$V. The method can be applied to any isochronous mass experiment irrespective of the accelerator facility. Furthermore, the method can be used as an on-line tool for checking the isochronous conditions of the storage ring.

  17. Rotationally Cold OH^{-} Ions in the Cryogenic Electrostatic Ion-Beam Storage Ring DESIREE.

    Science.gov (United States)

    Schmidt, H T; Eklund, G; Chartkunchand, K C; Anderson, E K; Kamińska, M; de Ruette, N; Thomas, R D; Kristiansson, M K; Gatchell, M; Reinhed, P; Rosén, S; Simonsson, A; Källberg, A; Löfgren, P; Mannervik, S; Zettergren, H; Cederquist, H

    2017-08-18

    We apply near-threshold laser photodetachment to characterize the rotational quantum level distribution of OH^{-} ions stored in the cryogenic ion-beam storage ring DESIREE at Stockholm University. We find that the stored ions relax to a rotational temperature of 13.4±0.2  K with 94.9±0.3% of the ions in the rotational ground state. This is consistent with the storage ring temperature of 13.5±0.5  K as measured with eight silicon diodes but in contrast to all earlier studies in cryogenic traps and rings where the rotational temperatures were always much higher than those of the storage devices at their lowest temperatures. Furthermore, we actively modify the rotational distribution through selective photodetachment to produce an OH^{-} beam where 99.1±0.1% of approximately one million stored ions are in the J=0 rotational ground state. We measure the intrinsic lifetime of the J=1 rotational level to be 145±28  s.

  18. Rotationally Cold OH- Ions in the Cryogenic Electrostatic Ion-Beam Storage Ring DESIREE

    Science.gov (United States)

    Schmidt, H. T.; Eklund, G.; Chartkunchand, K. C.; Anderson, E. K.; Kamińska, M.; de Ruette, N.; Thomas, R. D.; Kristiansson, M. K.; Gatchell, M.; Reinhed, P.; Rosén, S.; Simonsson, A.; Källberg, A.; Löfgren, P.; Mannervik, S.; Zettergren, H.; Cederquist, H.

    2017-08-01

    We apply near-threshold laser photodetachment to characterize the rotational quantum level distribution of OH- ions stored in the cryogenic ion-beam storage ring DESIREE at Stockholm University. We find that the stored ions relax to a rotational temperature of 13.4 ±0.2 K with 94.9 ±0.3 % of the ions in the rotational ground state. This is consistent with the storage ring temperature of 13.5 ±0.5 K as measured with eight silicon diodes but in contrast to all earlier studies in cryogenic traps and rings where the rotational temperatures were always much higher than those of the storage devices at their lowest temperatures. Furthermore, we actively modify the rotational distribution through selective photodetachment to produce an OH- beam where 99.1 ±0.1 % of approximately one million stored ions are in the J =0 rotational ground state. We measure the intrinsic lifetime of the J =1 rotational level to be 145 ±28 s .

  19. Time structure measurement of the SSRF storage ring using TRXEOL method

    Institute of Scientific and Technical Information of China (English)

    张招红; 姜政; 薛松; 郑丽芳

    2015-01-01

    In order to do alignment between the timing signal and the synchrotron X-ray pulse on the sample spot in the time domain, measuring time structure of the storage ring on the sample spot inside the experimental hutch is a foundational step during the time-resolved experiments using the pulsed synchrotron X-rays with the time structure defined by the storage ring. In this work, the method of time-resolved X-ray excited optical luminescence (TRXEOL) was designed and implemented to do the measurement. It is based on the principle of time-correlated single photon counting techniques. The measurement system consists of a spectrometer with a detector of photomultiplier tube, a timing system, a set of nuclear instrument modules and a luminescent material of zinc oxide. The measurement was performed on the X-ray absorbed fine structure spectrum beamline at Shanghai Synchrotron Radiation Facility. The results show that this method can be used to measure the time structure of the storage ring with a precision of less than 1 ns. The measurement system can also be used for the time-resolved research for the optical luminescent materials.

  20. Ionization and Recombination Measurements at the Heidelberg Heavy Ion Storage Ring TSR

    Science.gov (United States)

    Savin, D. W.; Hahn, M.; Lestinsky, M.; Novonty, O.; Bernhardt, D.; Mueller, A.; Schippers, S.; Krantz, C.; Wolf, A.

    2011-05-01

    Reliable ionization balance calculations are needed to analyze spectra from a wide range of cosmic sources including photoionized objects such as AGNs and X-ray binaries and electron ionized objects such as as stars, supernovae, galaxies, and clusters of galaxies. These theoretical charge state distributions (CSD) depend in turn upon the underlying atomic data. Of particular importance are reliable rate coefficients for dielectronic recombination (DR), which is the dominant electron-ion recombination recombination mechanism for most ions, and for electron impact ionization (EII). We are carrying out DR and EII measurements of astrophysically important ions using the heavy ion Test Storage Ring (TSR) at the Max-Plank-Institute for Nuclear Physics in Heidelberg, Germany. The storage ring measurements are largely free of the metastable contamination found in other experimental geometries. Storage ring measurements therefore result in more precise DR and EII reaction rate measurements. The measured rate coefficients can be used in modeling cosmic and laboratory plasmas as well as in the benchmarking of theoretical atomic calculations. Here we report results for selected recent DR and EII measurements.

  1. Electrostatic ring as the central machine of the Frankfurt Ion Storage Experiments

    Directory of Open Access Journals (Sweden)

    C. P. Welsch

    2004-08-01

    Full Text Available A small electrostatic storage ring is the central machine of the Frankfurt Ion Storage Experiments (FIRE which will be built at the new Stern-Gerlach Center of Frankfurt University. As a true multiuser, multipurpose facility with ion energies up to 50 keV, it will allow new methods to analyze complex many-particle systems from atoms to very large biomolecules. With envisaged storage times of some seconds and beam emittances in the order of a few mm mrad, measurements with up to 6 orders of magnitude better resolutions as compared to single-pass experiments become possible. In comparison to earlier designs, the ring lattice was modified in many details: Problems in earlier designs were related to, e.g., the detection of light particles and highly charged ions with different charge states. Therefore, the deflectors were redesigned completely, allowing a more flexible positioning of the diagnostics. Here, after an introduction to the concept of electrostatic machines, an overview of the planned FIRE is given and the ring lattice and elements are described in detail.

  2. Simulation of spin dynamics to measure electric dipole moments in storage rings

    Energy Technology Data Exchange (ETDEWEB)

    Rosenthal, Marcel; Lehrach, Andreas [Forschungszentrum Juelich GmbH (Germany). Inst. fuer Kernphysik; Collaboration: JEDI-Collaboration

    2013-07-01

    CP violation in the baryon sector, which is predicted by the Standard Model of Particle Physics, is too small to explain the matter and antimatter asymmetry in our universe. Permanent Electric Dipole Moments (EDMs) violate both P and T symmetries and are therefore, through the CPT theorem, also CP violating. No direct EDM measurements for protons, deuterons and light nuclei have been performed up to now. The JEDI collaboration at Forschungszentrum Juelich (FZJ) and the BNL-EDM collaboration at Brookhaven National Laboratory (BNL) pursue the goal to measure the EDMs of these particles in dedicated storage rings. Therefore different approaches are studied to reach an ultimate sensitivity of 10{sup -29} e.cm. A first direct measurement of the proton and deuteron EDM at a sensitivity level of 10{sup -24} e.cm will be performed in the existing conventional storage ring at FZJ, the Cooler Synchrotron COSY. Particle tracking simulations to explore the motion-correlated spin dynamics are a crucial part of feasibility studies of the planned storage ring EDM experiments. In a first step, a benchmarking of simulation codes with measurements at the Cooler Synchrotron COSY is performed.

  3. BEAM DIAGNOSTICS USING BPM SIGNALS FROM INJECTED AND STORED BEAMS IN A STORAGE RING

    Energy Technology Data Exchange (ETDEWEB)

    Wang, G.M.; Shaftan; T.; Cheng; W.X.; Fliller; R.; Heese; R.; Singh; O.; Willeke; F.

    2011-03-28

    Many modern light sources are operating in top-off injection mode or are being upgraded to top-off injection mode. The storage ring always has the stored beam and injected beam for top-off injection mode. So the BPM data is the mixture of both beam positions and the injected beam position cannot be measured directly. We propose to use dedicated wide band BPM electronics in the NSLS II storage ring to retrieve the injected beam trajectory with the singular value decomposition (SVD) method. The beam position monitor (BPM) has the capability to measure bunch-by-bunch beam position. Similar electronics can be used to measure the bunch-by-bunch beam current which is necessary to get the injection beam position. The measurement precision of current needs to be evaluated since button BPM sum signal has position dependence. The injected beam trajectory can be measured and monitored all the time without dumping the stored beam. We can adjust and optimize the injected beam trajectory to maximize the injection efficiency. We can also measure the storage ring acceptance by mapping the injected beam trajectory.

  4. The double electrostatic ion ring experiment: A unique cryogenic electrostatic storage ring for merged ion-beams studies

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, R. D.; Schmidt, H. T.; Andler, G.; Bjoerkhage, M.; Blom, M.; Braennholm, L.; Baeckstroem, E.; Danared, H.; Das, S.; Haag, N.; Hallden, P.; Hellberg, F.; Holm, A. I. S.; Johansson, H. A. B.; Kaellberg, A.; Kaellersjoe, G.; Larsson, M.; Leontein, S.; Liljeby, L.; Loefgren, P. [Department of Physics, Stockholm University, SE-106 91 Stockholm (Sweden); and others

    2011-06-15

    We describe the design of a novel type of storage device currently under construction at Stockholm University, Sweden, using purely electrostatic focussing and deflection elements, in which ion beams of opposite charges are confined under extreme high vacuum cryogenic conditions in separate ''rings'' and merged over a common straight section. The construction of this double electrostatic ion ring experiment uniquely allows for studies of interactions between cations and anions at low and well-defined internal temperatures and centre-of-mass collision energies down to about 10 K and 10 meV, respectively. Position sensitive multi-hit detector systems have been extensively tested and proven to work in cryogenic environments and these will be used to measure correlations between reaction products in, for example, electron-transfer processes. The technical advantages of using purely electrostatic ion storage devices over magnetic ones are many, but the most relevant are: electrostatic elements which are more compact and easier to construct; remanent fields, hysteresis, and eddy-currents, which are of concern in magnetic devices, are no longer relevant; and electrical fields required to control the orbit of the ions are not only much easier to create and control than the corresponding magnetic fields, they also set no upper mass limit on the ions that can be stored. These technical differences are a boon to new areas of fundamental experimental research, not only in atomic and molecular physics but also in the boundaries of these fields with chemistry and biology. For examples, studies of interactions with internally cold molecular ions will be particular useful for applications in astrophysics, while studies of solvated ionic clusters will be of relevance to aeronomy and biology.

  5. R-ratio of electron-positron annihilation into hadrons: higher-order pi2-terms

    CERN Document Server

    Nesterenko, A V

    2016-01-01

    High-energy behavior of R-ratio of electron-positron annihilation into hadrons is studied. In particular, it is argued that at any given order of perturbation theory the re-expansion of the R-ratio in the ultraviolet asymptotic can be reduced to the form of power series in the naive continuation of the strong running coupling into the timelike domain. The convergence range of the re-expanded R-ratio and the corresponding higher-order pi2-terms are discussed.

  6. Electron-Positron Pair Production in Structured Pulses of Electric Fields

    CERN Document Server

    Kohlfürst, Christian

    2012-01-01

    The non-perturbative electron-positron pair production in time-dependent electric fields is investigated. The quantum kinetic formalism is employed in order to calculate the electron density for various field configurations. The corresponding set of first order, ordinary differential equations is analyzed and numerically solved. The focus of this study lies on the dynamically assisted Schwinger effect in pulsed electric fields with at least two different time scales. Furthermore, interference effects arising in setups with multiple pulses are examined and first results for an optimization of the particle number yield by pulse-shaping are given.

  7. Coherent combs of anti-matter from nonlinear electron-positron pair creation

    CERN Document Server

    Krajewska, K

    2014-01-01

    Electron-positron pair creation in collisions of a modulated laser pulse with a high-energy photon (nonlinear Breit-Wheeler process) is studied by means of strong-field quantum electrodynamics. It is shown that the driving pulse modulations lead to appearance of comb structures in the energy spectra of produced positrons (electrons). It is demonstrated that these combs result from a coherent enhancement of probability amplitudes of pair creation from different modulations of the laser pulse. Thus, resembling the Young-double slit experiment for anti-matter (matter) waves.

  8. Strong electromagnetic waves in a magnetized relativistic electron-positron plasma

    Energy Technology Data Exchange (ETDEWEB)

    Yu, M.Y.; Shukla, P.K.; Rao, N.N. (Bochum Univ. (Germany, F.R.). Inst. fuer Theoretische Physik)

    1984-12-01

    It is shown that in a strongly magnetized relativistic electron-positron plasma, strongly localized large amplitude circularly polarized electromagnetic wave pulses exist. The localization is due to relativistic mass variation as well as ponderomotive force effects. Three types of pulses are found analytically: the sharply spiked pulse in a strongly magnetized cold plasma, the smooth pulse in a weak magnetized warm plasma, and the moderately spiked pulse for a weakly magnetized cold plasma. The physical mechanisms giving rise to these pulses are distinct for each case. Possible implications of our investigation to pulsar radiation are discussed.

  9. J-PET detector system for studies of the electron-positron annihilations

    Directory of Open Access Journals (Sweden)

    Pawlik-Niedźwiecka M.

    2016-01-01

    Full Text Available Jagiellonian Positron Emission Tomograph (J-PET has been recently constructed at the Jagiellonian University as a prototype of a cost-effective scanner for the metabolic imaging of the whole human body. J-PET detector is optimized for the measurement of momentum and polarization of photons from the electron-positron annihilations. It is built out of strips of plastic scintillators, forming three cylindrical layers. As detector of gamma quanta it will be used for studies of discrete symmetries and multiparticle entanglement of photons originating from the decays of ortho-positronium atoms.

  10. Electron-positron pair production in space-time varying external electric fields

    CERN Document Server

    Aleksandrov, I A; Shabaev, V M

    2016-01-01

    The Schwinger mechanism of the electron-positron pair production in the presence of strong external electric fields is analyzed numerically for the case of one- and two-dimensional field configurations where the external field depends both on time and one spatial coordinate. In order to provide this analysis, a new efficient numerical approach was developed. The number of particles created is obtained numerically and also compared with the analytical results for several exactly solvable one-dimensional backgrounds. For the case of two-dimensional field configurations a few generic properties of pair-creation process are found. The method employed is described in detail.

  11. J-PET detector system for studies of the electron-positron annihilations

    Science.gov (United States)

    Pawlik-Niedźwiecka, M.; Khreptak, O.; Gajos, A.; Wieczorek, A.; Alfs, D.; Bednarski, T.; Białas, P.; Curceanu, C.; Czerwiński, E.; Dulski, K.; Głowacz, B.; Gupta-Sharma, N.; Gorgol, M.; Hiesmayr, B. C.; Jasińska, B.; Kamińska, D.; Korcyl, G.; Kowalski, P.; Krzmień, W.; Krawczyk, N.; Kubicz, E.; Mohammed, M.; Niedźwiecki, Sz.; Raczyński, L.; Rudy, Z.; Silarski, M.; Wiślicki, W.; Zgardzińska, B.; Zieliński, M.; Moskal, P.

    2016-11-01

    Jagiellonian Positron Emission Tomograph (J-PET) has been recently constructed at the Jagiellonian University as a prototype of a cost-effective scanner for the metabolic imaging of the whole human body. J-PET detector is optimized for the measurement of momentum and polarization of photons from the electron-positron annihilations. It is built out of strips of plastic scintillators, forming three cylindrical layers. As detector of gamma quanta it will be used for studies of discrete symmetries and multiparticle entanglement of photons originating from the decays of ortho-positronium atoms.

  12. Resonance mechanism of the production of electron-positron pairs in a strong magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Rumyantsev, D. A., E-mail: rda@uniyar.ac.ru [Yaroslavl State Universiry (Russian Federation)

    2013-12-15

    The Compton-like process γe{sup ±} → e{sup ±}e{sup +}e{sup −} involving the production of an electron-positron pair in the interaction of an ultrarelativistic electron with a soft x-ray photon in the vicinity of the polar cap of a magnetar is considered. It is shown that the amplitude for this reaction has a resonance character. A simple analytic expression is obtained for the electron-absorption coefficient. Possible astrophysical implications of the resonance process γe{sup ±} → e{sup ±}e{sup +}e{sup −} are discussed.

  13. Electrostatic Nonlinear Structures in Dissipative Electron-Positron-Ion Quantum Plasmas

    Institute of Scientific and Technical Information of China (English)

    S. A. Khan; Q. Haque

    2008-01-01

    @@ Low frequency (in comparison to ion plasma frequency) ion-acoustic shocks and solitons in superdense electron-positron-ion quantum plasmas are studied.The quantum hydrodynamic model is used incorporating quantum Bohm forces and Fermi-Dirac statistical corrections to derive the deformed Korteweg de Vries-Burgers (dKdVB) equation in weakly nonlinear limit.The travelling wave solution of dKdVB equation is presented and results are discussed in different limits.It is found that shock height increases with increase of quantum pressure, positron concentration and dissipation.Further, it is seen that the width of soliton decreases with increase of quantum pressure.

  14. Shock formation in magnetised electron-positron plasmas: mechanism and timing

    Science.gov (United States)

    Stockem Novo, A.; Bret, A.; Sinha, U.

    2016-10-01

    The shock formation process in electron-positron pair plasmas is investigated in the presence of an ambient perpendicular magnetic field. In initially unmagnetised plasmas, which are dominated by the Weibel or filamentation instability, the shock formation time is a multiple of the saturation time of the linear instability. While in weakly magnetised plasmas the mechanism is still the same, higher magnetisations induce synchrotron maser modes such that the shock formation is dominated by magnetic reflection. As a consequence the formation times are reduced. The focus is on the detailed picture of the particle kinetics, in which the transition between Weibel and magneto-hydrodynamic shocks can be clearly identified.

  15. Nonplanar Ion-Acoustic Solitons in Electron-Positron-Ion Quantum Plasmas

    Institute of Scientific and Technical Information of China (English)

    S. A. Khan; S. Mahmood; Arshad M. Mirza

    2009-01-01

    @@ The propagation of nonplanar quantum ion-acoustic solitary waves in a dense, unmagnetized electron-positron-ion (e-p-i) plasma are studied by using the Korteweg-de Vries (KdV) model The quantum hydrodynamic (QHD) equations are used taking into account the quantum diffraction and quantum statistics corrections. The analytical and numerical solutions of KdV equation reveal that the nonplanar ion-acoustic solitons are modified significantly with quantum corrections and positron concentration, and behave differently in different geometries.

  16. Storage Rings in the Sky: Gamma Ray Bursts and Galactic Gravitational Collapse Stored Energy

    Science.gov (United States)

    Greyber, H. D.

    2004-05-01

    The recent discovery of almost 100% polarization of the prompt gamma ray emission from GRB021206, (1), confirms my 44 year old ``Strong" Magnetic Field" model (SMF) for galactic dynamics. In SMF, Storage Ring particles were accelerated long ago during the original gravitational collapse of the pregalactic/prequasar plasma cloud that is permeated by an almost uniform primordial magnetic field (2,3) The enormous, intense, slender, relativistic, stable, completely coherent Storage Ring stores a very small fraction of the huge galactic gravitational collapse energy in an almost radiationless state, unless disturbed. The concept of an Astrophysical Storage Ring was introduced by me in l961. At first it was to explain galactic structure, but soon it proved useful to explain active galactic nuclei (AGN) and the dynamics of quasar/AGN jets. AGN and galactic morphology, energetics and dynamics vary as the ratio of magnetic energy to rotational energy in the particular object. Gamma ray bursts (GRB) are due simply to a ``rock". i.e. a white dwarf, ordinary star, neutron sstar, asteroid, planet, etc. falling rapidly through the Storage Ring and being almost instantly vaporized into a hot plasma fireball, causing an electromagnetic shower (2) Then the fireball speeds into the huge organized magnetic field surrounding the current ring, thus generating very highly polarized prompt gamma ray emission (as seen in GRB021206) from the synchrotron radiation process. The timing fits the GRB observations nicely. For instance, a ``rock" racing at 1000 kilometers per second across a 20,000 km. path in the beam would produce a twenty second burst. Other times, a target might track across a short chord for a short burst. Space missions have shown that often typical currents in space plasmas are made up of slender filaments. Thus the puzzling less than one millisecond spikes observed in some GRB are simply describing the structure of that particular ring current at that particular time. 1

  17. Recommissioning of Duke Storage Ring with a HOM-Damped RF Cavity and a New Straight Section Lattice for FELs

    CERN Document Server

    Wu, Y K; Emamian, Mark; Faircloth, Joe; Gustavsson, J; Hartman, Steven M; Howell, C; Johnson, M; Li, Jingyi; Mikhailov, Stepan; Oakeley, Owen; Patterson, J; Pentico, Maurice; Popov, Victor; Rathbone, V; Swift, Gary; Wallace, Patrick W; Wang, Ping

    2005-01-01

    The Duke FEL lab operates a unique UV/VUV storage ring FEL and an FEL driven, nearly monochromatic, highly polarized, high intensity Compton gamma-ray source. The Duke storage ring light source is undergoing several phases of upgrade in order to significantly improve light source capabilities and performance. The 2004 phase included an upgrade of the RF system with a high-order mode damped RF cavity and a new 34 meter long straight section lattice to host new FEL wigglers in the next phase. This upgrade was completed in August 2004 and storage ring and light source commissioning were completed in November 2004. This paper will provide an overview of this upgrade project and report our commissioning experience of the storage ring and light sources.

  18. Spin motion at and near orbital resonance in storage rings with Siberian snakes I. At orbital resonance

    Energy Technology Data Exchange (ETDEWEB)

    Barber, D.P.; Vogt, M.

    2006-12-15

    Here, and in a sequel, we invoke the invariant spin field to provide an in-depth study of spin motion at and near low order orbital resonances in a simple model for the effects of vertical betatron motion in a storage ring with Siberian Snakes. This leads to a clear understanding, within the model, of the behaviour of the beam polarization at and near so-called snake resonances in proton storage rings. (orig.)

  19. Spin motion at and near orbital resonance in storage rings with Siberian Snakes. Part I: at orbital resonance

    CERN Document Server

    Barber, D P

    2006-01-01

    Here, and in a sequel, we invoke the invariant spin field to provide an in--depth study of spin motion at and near low order orbital resonances in a simple model for the effects of vertical betatron motion in a storage ring with Siberian Snakes. This leads to a clear understanding, within the model, of the behaviour of the beam polarisation at and near so--called snake resonances in proton storage rings.

  20. Present status of the NIJI-IV storage-ring free-electron lasers

    Energy Technology Data Exchange (ETDEWEB)

    Yamazaki, T.; Yamada, K.; Sei, N. [Electrotechnical Lab., Ibaraki (Japan)] [and others

    1995-12-31

    The tunable region of the free-electron-laser (FEL) wavelength with the NIJI-IV system is now 348{approximately}595 nm. After the lasing at 352 nm in 1994, the quality of the electron beam stored in the ring has been improved further, and the highest peak intensity of the laser obtained so far is more than 300 times as high as that of the resonated spontaneous emission. The macro-temporal structure of the lasing has been greatly improved. Recently, a single-bunch injection system was completed, and the system has been installed in the injector linac, which is expected to increase the peak stored-beam current. The commissioning and the test of the new system is under way. The beam transporting system from the linac to the ring is also being modified by increasing the number of quadrupole magnets. The experiments related to the FEL in the ultraviolet wavelength region will be begun in this coming May. The results and the status of the FEL experiments will be presented at the Conference.

  1. Low-Frequency Electrostatic Ion Surface Waves in Magnetized Electron-Positron Plasmas

    Science.gov (United States)

    Cho, Sang-Hoon; Lee, Hee J.

    The dispersion relations of a surface ion wave propagating on the interface between a warm electron-positron plasma and vacuum when a static magnetic field is directed either normal to the interface (x-wave) or parallel to the wave vector (z-wave) are solved analytically, and the influence of the magnetic field on the ion surface wave is investigated in detail using some numerical work. It is shown that ion surface waves do not exist if the magnetic field is large enough to make the ion gyrofrequency greater than the ion plasma frequency. The attenuation constant of x-waves is more attenuated than that of z-waves and the x-wave is more attenuated as the parameter normalized ion gyrofrequency ζ increases toward 1, but this tendency is reversed for the z-wave. The z-wave does not exist for k2λD2< (ζ/(1-ζ))(p + 1) while the x-wave exists over the whole range of k, where the fractional number p is the ratio between the unperturbed positron and the electron number density. Additionally, we compare the ion surface wave properties of electron-positron plasma with conventional electron-ion plasma.

  2. Disperson relation of finite amplitude Alfven wave in a relativistic electron- positron plasma

    CERN Document Server

    Hada, T; Muñoz, V; Hada, Tohru; Matsukiyo, Shuichi; Munoz, Victor

    2004-01-01

    The linear dispersion relation of a finite amplitude, parallel, circularly polarized Alfv\\'en wave in a relativistic electron-positron plasma is derived. In the nonrelativistic regime, the dispersion relation has two branches, one electromagnetic wave, with a low frequency cutoff at $\\sqrt{1+2\\omega_p^2/\\Omega_p^2}$ (where $\\omega_p=(4\\pi n e^2/m)^{1/2}$ is the electron/positron plasma frequency), and an Alfv\\'en wave, with high frequency cutoff at the positron gyrofrequency $\\Omega_p$. There is only one forward propagating mode for a given frequency. However, due to relativistic effects, there is no low frequency cutoff for the electromagnetic branch, and there appears a critical wave number above which the Alfv\\'en wave ceases to exist. This critical wave number is given by $ck_c/\\Omega_p=a/\\eta$, where $a=\\omega_p^2/\\Omega_p^2$ and $\\eta$ is the ratio between the Alfv\\'en wave magnetic field amplitude and the background magnetic field. In this case, for each frequency in the Alfv\\'en branch, two additional...

  3. Electroweak Measurements in Electron-Positron Collisions at W-Boson-Pair Energies at LEP

    CERN Document Server

    Schael, S.; Bruneliere, R.; Buskulic, D.; De Bonis, I.; Decamp, D.; Ghez, P.; Goy, C.; Jezequel, S.; Lees, J.P.; Lucotte, A.; Martin, F.; Merle, E.; Minard, M.N.; Nief, J.Y.; Odier, P.; Pietrzyk, B.; Trocme, B.; Bravo, S.; Casado, M.P.; Chmeissani, M.; Comas, P.; Crespo, J.M.; Fernandez, E.; Fernandez-Bosman, M.; Garrido, Ll.; Grauges, E.; Juste, A.; Martinez, M.; Merino, G.; Miquel, R.; Mir, Ll. M.; Orteu, S.; Pacheco, A.; Park, I.C.; Perlas, J.; Riu, I.; Ruiz, H.; Sanchez, F.; Colaleo, A.; Creanza, D.; De Filippis, N.; De Palma, M.; Iaselli, G.; Maggi, G.; Maggi, M.; Nuzzo, S.; Ranieri, A.; Raso, G.; Ruggieri, F.; Selvaggi, G.; Silvestris, L.; Tempesta, P.; Tricomi, A.; Zito, G.; Huang, X.; Lin, J.; Ouyang, Q.; Wang, T.; Xie, Y.; Xu, R.; Xue, S.; Zhang, J.; Zhang, L.; Zhao, W.; Abbaneo, D.; Bazarko, A.; Becker, U.; Boix, G.; Bird, F.; Blucher, E.; Bonvicini, B.; Bright-Thomas, P.; Barklow, T.; Buchmuller, O.; Cattaneo, M.; Cerutti, F.; Ciulli, V.; Clerbaux, B.; Drevermann, H.; Forty, R.W.; Frank, M.; Greening, T.C.; Hagelberg, R.; Halley, A.W.; Gianotti, F.; Girone, M.; Hansen, J.B.; Harvey, J.; Jacobsen, R.; Hutchcroft, D.E.; Janot, P.; Jost, B.; Knobloch, J.; Kado, M.; Lehraus, I.; Lazeyras, P.; Maley, P.; Mato, P.; May, J.; Moutoussi, A.; Pepe-Altarelli, M.; Ranjard, F.; Rolandi, L.; Schlatter, D.; Schmitt, B.; Schneider, O.; Tejessy, W.; Teubert, F.; Tomalin, I.R.; Tournefier, E.; Veenhof, R.; Valassi, A.; Wiedenmann, W.; Wright, A.E.; Ajaltouni, Z.; Badaud, F.; Chazelle, G.; Deschamps, O.; Dessagne, S.; Falvard, A.; Ferdi, C.; Fayolle, D.; Gay, P.; Guicheney, C.; Henrard, P.; Jousset, J.; Michel, B.; Monteil, S.; Montret, J.C.; Pallin, D.; Pascolo, J.M.; Perret, P.; Podlyski, F.; Bertelsen, H.; Fernley, T.; Hansen, J.D.; Hansen, J.R.; Hansen, P.H.; Kraan, A.C.; Lindahl, A.; Mollerud, R.; Nilsson, B.S.; Rensch, B.; Waananen, A.; Daskalakis, G.; Kyriakis, A.; Markou, C.; Simopoulou, E.; Siotis, I.; Vayaki, A.; Zachariadou, K.; Blondel, A.; Bonneaud, G.; Brient, J.C.; Machefert, F.; Rouge, A.; Rumpf, M.; Swynghedauw, M.; Tanaka, R.; Verderi, M.; Videau, H.; Ciulli, V.; Focardi, E.; Parrini, G.; Zachariadou, K.; Corden, M.; Georgiopoulos, C.; Antonelli, A.; Antonelli, M.; Bencivenni, G.; Bologna, G.; Bossi, F.; Campana, P.; Capon, G.; Cerutti, F.; Chiarella, V.; Felici, G.; Laurelli, P.; Mannocchi, G.; Murtas, G.P.; Passalacqua, L.; Picchi, P.; Colrain, P.; ten Have, I.; Hughes, I.S.; Kennedy, J.; Knowles, I.G.; Lynch, J.G.; Morton, W.T.; Negus, P.; O'Shea, V.; Raine, C.; Reeves, P.; Scarr, J.M.; Smith, K.; Thompson, A.S.; Turnbull, R.M.; Wasserbaech, S.; Buchmuller, O.; Cavanaugh, R.; Dhamotharan, S.; Geweniger, C.; Hanke, P.; Hansper, G.; Hepp, V.; Kluge, E.E.; Putzer, A.; Sommer, J.; Stenzel, H.; Tittel, K.; Werner, W.; Wunsch, M.; Beuselinck, R.; Binnie, D.M.; Cameron, W.; Davies, G.; Dornan, P.J.; Goodsir, S.; Marinelli, N.; Martin, E.B.; Nash, J.; Nowell, J.; Rutherford, S.A.; Sedgbeer, J.K.; Thompson, J.C.; White, R.; Williams, M.D.; Ghete, V.M.; Girtler, P.; Kneringer, E.; Kuhn, D.; Rudolph, G.; Bouhova-Thacker, E.; Bowdery, C.K.; Buck, P.G.; Clarke, D.P.; Ellis, G.; Finch, A.J.; Foster, F.; Hughes, G.; Jones, R.W.L.; Keemer, N.R.; Pearson, M.R.; Robertson, N.A.; Sloan, T.; Smizanska, M.; Snow, S.W.; Williams, M.I.; van der Aa, O.; Delaere, C.; Leibenguth, G.; Lemaitre, V.; Bauerdick, L.A.T.; Blumenschein, U.; van Gemmeren, P.; Giehl, I.; Holldorfer, F.; Jakobs, K.; Kasemann, M.; Kayser, F.; Kleinknecht, K.; Muller, A.S.; Quast, G.; Renk, B.; Rohne, E.; Sander, H.G.; Schmeling, S.; Wachsmuth, H.; Wanke, R.; Zeitnitz, C.; Ziegler, T.; Aubert, J.J.; Benchouk, C.; Bonissent, A.; Carr, J.; Coyle, P.; Curtil, C.; Ealet, A.; Etienne, F.; Fouchez, D.; Motsch, F.; Payre, P.; Rousseau, D.; Tilquin, A.; Talby, M.; Thulasidas, M.; Aleppo, M.; Antonelli, M.; Ragusa, F.; Buscher, V.; David, A.; Dietl, H.; Ganis, G.; Huttmann, K.; Lutjens, G.; Mannert, C.; Manner, W.; Moser, H.G.; Settles, R.; Seywerd, H.; Stenzel, H.; Villegas, M.; Wiedenmann, W.; Wolf, G.; Azzurri, P.; Boucrot, J.; Callot, O.; Chen, S.; Cordier, A.; Davier, M.; Duflot, L.; Grivaz, J.F.; Heusse, Ph.; Jacholkowska, A.; Le Diberder, F.; Lefrancois, J.; Mutz, A.M.; Schune, M.H.; Serin, L.; Veillet, J.J.; Videau, I.; Zerwas, D.; Azzurri, P.; Bagliesi, G.; Bettarini, S.; Boccali, T.; Bozzi, C.; Calderini, G.; Dell'Orso, R.; Fantechi, R.; Ferrante, I.; Fidecaro, F.; Foa, L.; Giammanco, A.; Giassi, A.; Gregorio, A.; Ligabue, F.; Lusiani, A.; Marrocchesi, P.S.; Messineo, A.; Palla, F.; Rizzo, G.; Sanguinetti, G.; Sciaba, A.; Sguazzoni, G.; Spagnolo, P.; Steinberger, J.; Tenchini, R.; Vannini, C.; Venturi, A.; Verdini, P.G.; Awunor, O.; Blair, G.A.; Cowan, G.; Garcia-Bellido, A.; Green, M.G.; Medcalf, T.; Misiejuk, A.; Strong, J.A.; Teixeira-Dias, P.; Botterill, D.R.; Clifft, R.W.; Edgecock, T.R.; Edwards, M.; Haywood, S.J.; Norton, P.R.; Tomalin, I.R.; Ward, J.J.; Bloch-Devaux, B.; Boumediene, D.; Colas, P.; Emery, S.; Fabbro, B.; Kozanecki, W.; Lancon, E.; Lemaire, M.C.; Locci, E.; Perez, P.; Rander, J.; Renardy, J.F.; Roussarie, A.; Schuller, J.P.; Schwindling, J.; Tuchming, B.; Vallage, B.; Black, S.N.; Dann, J.H.; Kim, H.Y.; Konstantinidis, N.; Litke, A.M.; McNeil, M.A.; Taylor, G.; Booth, C.N.; Cartwright, S.; Combley, F.; Hodgson, P.N.; Lehto, M.; Thompson, L.F.; Affholderbach, K.; Barberio, E.; Bohrer, A.; Brandt, S.; Burkhardt, H.; Feigl, E.; Grupen, C.; Hess, J.; Lutters, G.; Meinhard, H.; Minguet-Rodriguez, J.; Mirabito, L.; Misiejuk, A.; Neugebauer, E.; Ngac, A.; Prange, G.; Rivera, F.; Saraiva, P.; Schafer, U.; Sieler, U.; Smolik, L.; Stephan, F.; Trier, H.; Apollonio, M.; Borean, C.; Bosisio, L.; Della Marina, R.; Giannini, G.; Gobbo, B.; Musolino, G.; Pitis, L.; He, H.; Kim, H.; Putz, J.; Rothberg, J.; Armstrong, S.R.; Bellantoni, L.; Berkelman, K.; Cinabro, D.; Conway, J.S.; Cranmer, K.; Elmer, P.; Feng, Z.; Ferguson, D.P.S.; Gao, Y.; Gonzalez, S.; Grahl, J.; Harton, J.L.; Hayes, O.J.; Hu, H.; Jin, S.; Johnson, R.P.; Kile, J.; McNamara, P.A., III; Nielsen, J.; Orejudos, W.; Pan, Y.B.; Saadi, Y.; Scott, I.J.; Sharma, V.; Walsh, A.M.; Walsh, J.; Wear, J.; von Wimmersperg-Toeller, J.H.; Wiedenmann, W.; Wu, J.; Wu, S.L.; Wu, X.; Yamartino, J.M.; Zobernig, G.; Dissertori, G.; Abdallah, J.; Abreu, P.; Adam, W.; Adzic, P.; Albrecht, T.; Alemany-Fernandez, R.; Allmendinger, T.; Allport, P.P.; Amaldi, U.; Amapane, N.; Amato, S.; Anashkin, E.; Andreazza, A.; Andringa, S.; Anjos, N.; Antilogus, P.; Apel, W-D.; Arnoud, Y.; Ask, S.; Asman, B.; Augustin, J.E.; Augustinus, A.; Baillon, P.; Ballestrero, A.; Bambade, P.; Barbier, R.; Bardin, D.; Barker, G.J.; Baroncelli, A.; Battaglia, M.; Baubillier, M.; Becks, K-H.; Begalli, M.; Behrmann, A.; Belous, K.; Ben-Haim, E.; Benekos, N.; Benvenuti, A.; Berat, C.; Berggren, M.; Berntzon, L.; Bertrand, D.; Besancon, M.; Besson, N.; Bloch, D.; Blom, M.; Bluj, M.; Bonesini, M.; Boonekamp, M.; Booth, P.S.L.; Borisov, G.; Botner, O.; Bouquet, B.; Bowcock, T.J.V.; Boyko, I.; Bracko, M.; Brenner, R.; Brodet, E.; Bruckman, P.; Brunet, J.M.; Bugge, L.; Buschbeck, B.; Buschmann, P.; Calvi, M.; Camporesi, T.; Canale, V.; Carena, F.; Castro, N.; Cavallo, F.; Chapkin, M.; Charpentier, Ph.; Checchia, P.; Chierici, R.; Chliapnikov, P.; Chudoba, J.; Cieslik, K.; Collins, P.; Contri, R.; Cosme, G.; Cossutti, F.; Costa, M.J.; Crawley, B.; Crennell, D.; Cuevas, J.; D'Hondt, J.; Dalmau, J.; da Silva, T.; Da Silva, W.; Della Ricca, G.; De Angelis, A.; De Boer, W.; De Clercq, C.; De Lotto, B.; De Maria, N.; De Min, A.; De Paula, L.; Di Ciaccio, L.; Di Simone, A.; Doroba, K.; Drees, J.; Dris, M.; Duperrin, A.; Eigen, G.; Ekelof, T.; Ellert, M.; Elsing, M.; Espirito Santo, M.C.; Fanourakis, G.; Fassouliotis, D.; Feindt, M.; Fernandez, J.; Ferrer, A.; Ferro, F.; Flagmeyer, U.; Foeth, H.; Fokitis, E.; Fulda-Quenzer, F.; Fuster, J.; Gandelman, M.; Garcia, C.; Gavillet, Ph.; Gazis, E.; Gele, D.; Gokieli, R.; Golob, B.; Gomez-Ceballos, G.; Goncalves, P.; Graziani, E.; Grosdidier, G.; Grzelak, K.; Guy, J.; Haag, C.; Hallgren, A.; Hamacher, K.; Hamilton, K.; Haug, S.; Hauler, F.; Hedberg, V.; Hennecke, M.; Herr, H.; Hoffman, J.; Holmgren, S-O.; Holt, P.J.; Houlden, M.A.; Hultqvist, K.; Jackson, J.N.; Jarlskog, G.; Jarry, P.; Jeans, D.; Johansson, E.K.; Johansson, P.D.; Jonsson, P.; Joram, C.; Jungermann, L.; Kapusta, F.; Katsanevas, S.; Katsoufis, E.; Kernel, G.; Kersevan, B.P.; Kerzel, U.; Kiiskinen, A.; King, B.T.; Kjaer, N.J.; Kluit, P.; Kokkinias, P.; Kostioukhine, V.; Kourkoumelis, C.; Kouznetsov, O.; Krumstein, Z.; Kucharczyk, M.; Lamsa, J.; Leder, G.; Ledroit, F.; Leinonen, L.; Leitner, R.; Lemonne, J.; Lepeltier, V.; Lesiak, T.; Libby, J.; Liebig, W.; Liko, D.; Lipniacka, A.; Lopes, J.H.; Lopez, J.M.; Loukas, D.; Lutz, P.; Lyons, L.; MacNaughton, J.; Malek, A.; Maltezos, S.; Mandl, F.; Marco, J.; Marco, R.; Marechal, B.; Margoni, M.; Marin, J-C.; Mariotti, C.; Markou, A.; Martinez-Rivero, C.; Masik, J.; Mastroyiannopoulos, N.; Matorras, F.; Matteuzzi, C.; Mazzucato, F.; Mazzucato, M.; Nulty, R.Mc; Meroni, C.; Meyer, W.T.; Migliore, E.; Mitaroff, W.; Mjoernmark, U.; Moa, T.; Moch, M.; Moenig, K.; Monge, R.; Montenegro, J.; Moraes, D.; Morettini, P.; Mueller, U.; Muenich, K.; Mulders, M.; Mundim, L.; Murray, W.; Muryn, B.; Myatt, G.; Myklebust, T.; Nassiakou, M.; Navarria, F.; Nawrocki, K.; Nemecek, S.; Nicolaidou, R.; Nikolaenko, V.; Nikolenko, M.; Oblakowska-Mucha, A.; Obraztsov, V.; Olshevski, A.; Onofre, A.; Orava, R.; Osterberg, K.; Ouraou, A.; Oyanguren, A.; Paganoni, M.; Paiano, S.; Palacios, J.P.; Palka, H.; Papadopoulou, Th. D.; Pape, L.; Parkes, C.; Parodi, F.; Parzefall, U.; Passeri, A.; Passon, O.; Perepelitsa, V.; Perrotta, A.; Petrolini, A.; Piedra, J.; Pieri, L.; Pierre, F.; Pimenta, M.; Podobnik, T.; Poireau, V.; Pol, M.E.; Polok, G.; Poropat, P.; Pozdniakov, V.; Pukhaeva, N.; Pullia, A.; Radojicic, D.; Rames, J.; Ramler, L.; Read, A.; Rebecchi, P.; Rehn, J.; Reid, D.; Reinhardt, R.; Renton, P.; Richard, F.; Ridky, J.; Ripp-Baudot, I.; Rivero, M.; Rodriguez, D.; Romero, A.; Ronchese, P.; Rosenberg, E.; Roudeau, P.; Rovelli, T.; Ruhlmann-Kleider, V.; Ryabtchikov, D.; Sadovsky, A.; Salmi, L.; Salt, J.; Sander, C.; Savoy-Navarro, A.; Schwickerath, U.; Segar, A.; Sekulin, R.; Siebel, M.; Simard, L.; Sisakian, A.; Smadja, G.; Smirnova, O.; Sokolov, A.; Sopczak, A.; Sosnowski, R.; Spassov, T.; Stanitzki, M.; Stocchi, A.; Strauss, J.; Stugu, B.; Szczekowski, M.; Szeptycka, M.; Szumlak, T.; Tabarelli, T.; Taffard, A.C.; Tegenfeldt, F.; Terranova, F.; Thomas, J.; Timmermans, J.; Tkatchev, L.; Tobin, M.; Todorovova, S.; Tome, B.; Tonazzo, A.; Tortosa, P.; Travnicek, P.; Treille, D.; Tristram, G.; Trochimczuk, M.; Troncon, C.; Turluer, M-L.; Tyapkin, I.A.; Tyapkin, P.; Tzamarias, S.; Uvarov, V.; Valenti, G.; Van Dam, P.; Van Eldik, J.; Van Lysebetten, A.; van Remortel, N.; Van Vulpen, I.; Vegni, G.; Veloso, F.; Venus, W.; Verbeure, F.; Verdier, P.; Verzi, V.; Vilanova, D.; Vitale, L.; Vrba, V.; Wahlen, H.; Washbrook, A.J.; Weiser, C.; Wicke, D.; Wickens, J.; Wilkinson, G.; Winter, M.; Witek, M.; Yushchenko, O.; Zalewska, A.; Zalewski, P.; Zavrtanik, D.; Zhuravlov, V.; Zimine, N.I.; Zintchenko, A.; Achard, P.; Adriani, O.; Aguilar-Benitez, M.; Alcaraz, J.; Alemanni, G.; Allaby, J.; Aloisio, A.; Alviggi, M.G.; Anderhub, H.; Andreev, V.P.; Anselmo, F.; Arefiev, A.; Azemoon, T.; Aziz, T.; Bagnaia, P.; Bajo, A.; Baksay, G.; Baksay, L.; Baldew, S.V.; Banerjee, S.; Banerjee, Sw.; Barczyk, A.; Barillere, R.; Bartalini, P.; Basile, M.; Batalova, N.; Battiston, R.; Bay, A.; Becker, U.; Behner, F.; Bellucci, L.; Berbeco, R.; Berdugo, J.; Berges, P.; Bertucci, B.; Betev, B.L.; Biasini, M.; Biglietti, M.; Biland, A.; Blaising, J.J.; Blyth, S.C.; Bobbink, G.J.; Bohm, A.; Boldizsar, L.; Borgia, B.; Bottai, S.; Bourilkov, D.; Bourquin, M.; Braccini, S.; Branson, J.G.; Brochu, F.; Burger, J.D.; Burger, W.J.; Cai, X.D.; Capell, M.; Cara Romeo, G.; Carlino, G.; Cartacci, A.; Casaus, J.; Cavallari, F.; Cavallo, N.; Cecchi, C.; Cerrada, M.; Chamizo, M.; Chang, Y.H.; Chemarin, M.; Chen, A.; Chen, G.; Chen, G.M.; Chen, H.F.; Chen, H.S.; Chiefari, G.; Cifarelli, L.; Cindolo, F.; Clare, I.; Clare, R.; Coignet, G.; Colino, N.; Costantini, S.; de la Cruz, B.; Cucciarelli, S.; De Asmundis, R.; D'eglon, P.; Debreczeni, J.; Degre, A.; Dehmelt, K.; Deiters, K.; della Volpe, D.; Delmeire, E.; Denes, P.; DeNotaristefani, F.; De Salvo, A.; Diemoz, M.; Dierckxsens, M.; Dionisi, C.; Dittmar, M.; Doria, A.; Dova, M.T.; Duchesneau, D.; Duda, M.; Echenard, B.; Eline, A.; El Hage, A.; El Mamouni, H.; Engler, A.; Eppling, F.J.; Extermann, P.; Falagan, M.A.; Falciano, S.; Favara, A.; Fay, J.; Fedin, O.; Felcini, M.; Ferguson, T.; Fesefeldt, H.; Fiandrini, E.; Field, J.H.; Filthaut, F.; Fisher, P.H.; Fisher, W.; Forconi, G.; Freudenreich, K.; Furetta, C.; Galaktionov, Yu.; Ganguli, S.N.; Garcia-Abia, P.; Gataullin, M.; Gentile, S.; Giagu, S.; Gong, Z.F.; Grenier, G.; Grimm, O.; Gruenewald, M.W.; Gupta, V.K.; Gurtu, A.; Gutay, L.J.; Haas, D.; Hatzifotiadou, D.; Hebbeker, T.; Herve, A.; Hirschfelder, J.; Hofer, H.; Hohlmann, M.; Holzner, G.; Hou, S.R.; Jin, B.N.; Jindal, P.; Jones, L.W.; de Jong, P.; Josa-Mutuberria, I.; Kaur, M.; Kienzle-Focacci, M.N.; Kim, J.K.; Kirkby, J.; Kittel, W.; Klimentov, A.; Konig, A.C.; Kopal, M.; Koutsenko, V.; Kraber, M.; Kraemer, R.W.; Kruger, A.; Kunin, A.; Ladron de Guevara, P.; Laktineh, I.; Landi, G.; Lebeau, M.; Lebedev, A.; Lebrun, P.; Lecomte, P.; Lecoq, P.; Le Coultre, P.; Le Goff, J.M.; Leiste, R.; Levtchenko, M.; Levtchenko, P.; Li, C.; Likhoded, S.; Lin, C.H.; Lin, W.T.; Linde, F.L.; Lista, L.; Liu, Z.A.; Lohmann, W.; Longo, E.; Lu, Y.S.; Luci, C.; Luminari, L.; Lustermann, W.; Ma, W.G.; Malgeri, L.; Malinin, A.; Mana, C.; Mans, J.; Martin, J.P.; Marzano, F.; Mazumdar, K.; McNeil, R.R.; Mele, S.; Merola, L.; Meschini, M.; Metzger, W.J.; Mihul, A.; Milcent, H.; Mirabelli, G.; Mnich, J.; Mohanty, G.B.; Muanza, G.S.; Muijs, A.J.M.; Musy, M.; Nagy, S.; Natale, S.; Napolitano, M.; Nessi-Tedaldi, F.; Newman, H.; Nisati, A.; Novak, T.; Nowak, H.; Ofierzynski, R.; Organtini, G.; Palomares, C.; Paolucci, P.; Paramatti, R.; Passaleva, G.; Patricelli, S.; Paul, T.; Pauluzzi, M.; Paus, C.; Pauss, F.; Pedace, M.; Pensotti, S.; Perret-Gallix, D.; Piccolo, D.; Pierella, F.; Pieri, M.; Pioppi, M.; Pirou'e, P.A.; Pistolesi, E.; Plyaskin, V.; Pohl, M.; Pojidaev, V.; Pothier, J.; Prokofiev, D.; Rahal-Callot, G.; Rahaman, M.A.; Raics, P.; Raja, N.; Ramelli, R.; Rancoita, P.G.; Ranieri, R.; Raspereza, A.; Razis, P.; Rembeczki, S.; Ren, D.; Rescigno, M.; Reucroft, S.; Riemann, S.; Riles, K.; Roe, B.P.; Romero, L.; Rosca, A.; Rosemann, C.; Rosenbleck, C.; Rosier-Lees, S.; Roth, S.; Rubio, J.A.; Ruggiero, G.; Rykaczewski, H.; Sakharov, A.; Saremi, S.; Sarkar, S.; Salicio, J.; Sanchez, E.; Schafer, C.; Schegelsky, V.; Schopper, H.; Schotanus, D.J.; Sciacca, C.; Servoli, L.; Shevchenko, S.; Shivarov, N.; Shoutko, V.; Shumilov, E.; Shvorob, A.; Son, D.; Souga, C.; Spillantini, P.; Steuer, M.; Stickland, D.P.; Stoyanov, B.; Straessner, A.; Sudhakar, K.; Sultanov, G.; Sun, L.Z.; Sushkov, S.; Suter, H.; Swain, J.D.; Szillasi, Z.; Tang, X.W.; Tarjan, P.; Tauscher, L.; Taylor, L.; Tellili, B.; Teyssier, D.; Timmermans, C.; Ting, S.C.C.; Ting, S.M.; Tonwar, S.C.; Toth, J.; Tully, C.; Ulbricht, J.; Valente, E.; Van de Walle, R.T.; Vasquez, R.; Vesztergombi, G.; Vetlitsky, I.; Viertel, G.; Vivargent, M.; Vlachos, S.; Vodopianov, I.; Vogel, H.; Vogt, H.; Vorobiev, I.; Vorobyov, A.A.; Wadhwa, M.; Wang, Q.; Wang, X.L.; Wang, Z.M.; Weber, M.; Wynhoff, S.; Xia, L.; Xu, Z.Z.; Yamamoto, J.; Yang, B.Z.; Yang, C.G.; Yang, H.J.; Yang, M.; Yeh, S.C.; Zalite, An.; Zalite, Yu.; Zhang, Z.P.; Zhao, J.; Zhu, G.Y.; Zhu, R.Y.; Zhuang, H.L.; Zichichi, A.; Zimmermann, B.; Zoller, M.; Abbiendi, G.; Ackerstaff, K.; Ainsley, C.; Akesson, P.F.; Alexander, G.; Allison, J.; Altekamp, N.; Ametewee, K.; Anagnostou, G.; Anderson, K.J.; Anderson, S.; Arcelli, S.; Asai, S.; Ashby, S.F.; Axen, D.; Azuelos, G.; Ball, A.H.; Bailey, I.; Barberio, E.; Barillari, T.; Barlow, R.J.; Bartoldus, R.; Batley, R.J.; Baumann, S.; Bechtle, P.; Bechtluft, J.; Beeston, C.; Behnke, T.; Bell, K.W.; Bell, P.J.; Bella, G.; Bellerive, A.; Benelli, G.; Bentvelsen, S.; Berlich, P.; Bethke, S.; Biebel, O.; Boeriu, O.; Blobel, V.; Bloodworth, I.J.; Bloomer, J.E.; Bobinski, M.; Bock, P.; Bonacorsi, D.; Bosch, H.M.; Boutemeur, M.; Bouwens, B.T.; Braibant, S.; Bright-Thomas, P.; Brigliadori, L.; Brown, R.M.; Burckhart, H.J.; Burgard, C.; Burgin, R.; Cammin, J.; Campana, S.; Capiluppi, P.; Carnegie, R.K.; Carter, A.A.; Carter, J.R.; Chang, C.Y.; Charlton, D.G.; Chrisman, D.; Ciocca, C.; Clarke, P.E.L.; Clay, E.; Cohen, I.; Conboy, J.E.; Cooke, O.C.; Couchman, J.; Couyoumtzelis, C.; Coxe, R.L.; Csilling, A.; Cuffiani, M.; Dado, S.; Dallapiccola, C.; Dallavalle, M.; Dallison, S.; de Jong, S.; De Roeck, A.; Dervan, P.; De Wolf, E.A.; del Pozo, L.A.; Desch, K.; Dienes, B.; Dixit, M.S.; do Couto e Silva, E.; Donkers, M.; Doucet, M.; Dubbert, J.; Duchovni, E.; Duckeck, G.; Duerdoth, I.P.; Edwards, J.E.G.; Estabrooks, P.G.; Etzion, E.; Evans, H.G.; Evans, M.; Fabbri, F.; Fanti, M.; Fath, P.; Feld, L.; Ferrari, P.; Fiedler, F.; Fierro, M.; Fischer, H.M.; Fleck, I.; Folman, R.; Fong, D.G.; Ford, M.; Foucher, M.; Frey, A.; Furtjes, A.; Futyan, D.I.; Gagnon, P.; Gary, J.W.; Gascon, J.; Gascon-Shotkin, S.M.; Gaycken, G.; Geddes, N.I.; Geich-Gimbel, C.; Geralis, T.; Giacomelli, G.; Giacomelli, P.; Giacomelli, R.; Gibson, V.; Gibson, W.R.; Gingrich, D.M.; Giunta, M.; Glenzinski, D.; Goldberg, J.; Goodrick, M.J.; Gorn, W.; Graham, K.; Grandi, C.; Gross, E.; Grunhaus, J.; Gruwe, M.; Gunther, P.O.; Gupta, A.; Hajdu, C.; Hamann, M.; Hanson, G.G.; Hansroul, M.; Hapke, M.; Harder, K.; Harel, A.; Hargrove, C.K.; Harin-Dirac, M.; Hart, P.A.; Hartmann, C.; Hauke, A.; Hauschild, M.; Hawkes, C.M.; Hawkings, R.; Hemingway, R.J.; Hensel, C.; Herndon, M.; Herten, G.; Heuer, R.D.; Hildreth, M.D.; Hill, J.C.; Hillier, S.J.; Hilse, T.; Hobson, P.R.; Hocker, A.; Hoffman, K.; Homer, R.J.; Honma, A.K.; Horvath, D.; Hossain, K.R.; Howard, R.; Hughes-Jones, R.E.; Huntemeyer, P.; Hutchcroft, D.E.; Igo-Kemenes, P.; Imrie, D.C.; Ingram, M.R.; Ishii, K.; Jacob, F.R.; Jawahery, A.; Jeffreys, P.W.; Jeremie, H.; Jimack, M.; Joly, A.; Jones, C.R.; Jones, G.; Jones, M.; Jones, R.W.L.; Jost, U.; Jovanovic, P.; Junk, T.R.; Kanaya, N.; Kanzaki, J.; Karapetian, G.; Karlen, D.; Kartvelishvili, V.; Kawagoe, K.; Kawamoto, T.; Keeler, R.K.; Kellogg, R.G.; Kennedy, B.W.; Kim, D.H.; King, B.J.; Kirk, J.; Klein, K.; Klier, A.; Kluth, S.; Kobayashi, T.; Kobel, M.; Koetke, D.S.; Kokott, T.P.; Kolrep, M.; Komamiya, S.; Kowalewski, R.V.; Kramer, T.; Krasznahorkay, A., Jr.; Kress, T.; Krieger, P.; von Krogh, J.; Kuhl, T.; Kupper, M.; Kyberd, P.; Lafferty, G.D.; Lahmann, R.; Lai, W.P.; Landsman, H.; Lanske, D.; Lauber, J.; Lautenschlager, S.R.; Lawson, I.; Layter, J.G.; Lazic, D.; Lee, A.M.; Lefebvre, E.; Leins, A.; Lellouch, D.; Letts, J.; Levinson, L.; Lewis, C.; Liebisch, R.; Lillich, J.; List, B.; List, J.; Littlewood, C.; Lloyd, A.W.; Lloyd, S.L.; Loebinger, F.K.; Long, G.D.; Losty, M.J.; Lu, J.; Ludwig, A.; Ludwig, J.; Macchiolo, A.; Macpherson, A.; Mader, W.; Mannelli, M.; Marcellini, S.; Marchant, T.E.; Markus, C.; Martin, A.J.; Martin, J.P.; Martinez, G.; Mashimo, T.; Matthews, W.; Mattig, P.; McDonald, W.J.; McKenna, J.; Mckigney, E.A.; McMahon, T.J.; McNab, A.I.; McPherson, R.A.; Mendez-Lorenzo, P.; Meijers, F.; Menges, W.; Menke, S.; Merritt, F.S.; Mes, H.; Meyer, N.; Meyer, J.; Michelini, A.; Mihara, S.; Mikenberg, G.; Miller, D.J.; Mir, R.; Mohr, W.; Montanari, A.; Mori, T.; Morii, M.; Muller, U.; Mutter, A.; Nagai, K.; Nakamura, I.; Nanjo, H.; Neal, H.A.; Nellen, B.; Nijjhar, B.; Nisius, R.; O'Neale, S.W.; Oakham, F.G.; Odorici, F.; Ogren, H.O.; Oh, A.; Okpara, A.; Oldershaw, N.J.; Omori, T.; Oreglia, M.J.; Orito, S.; Pahl, C.; Palinkas, J.; Pasztor, G.; Pater, J.R.; Patrick, G.N.; Patt, J.; Pearce, M.J.; Petzold, S.; Pfeifenschneider, P.; Pilcher, J.E.; Pinfold, J.; Plane, D.E.; Poffenberger, P.; Polok, J.; Poli, B.; Pooth, O.; Posthaus, A.; Przybycien, M.; Przysiezniak, H.; Quadt, A.; Rabbertz, K.; Rees, D.L.; Rembser, C.; Renkel, P.; Rick, H.; Rigby, D.; Robertson, S.; Robins, S.A.; Rodning, N.; Roney, J.M.; Rooke, A.; Ros, E.; Rosati, S.; Roscoe, K.; Rossi, A.M.; Rosvick, M.; Routenburg, P.; Rozen, Y.; Runge, K.; Runolfsson, O.; Ruppel, U.; Rust, D.R.; Rylko, R.; Sachs, K.; Saeki, T.; Sahr, O.; Sarkisyan, E.K.G.; Sasaki, M.; Sbarra, C.; Schaile, A.D.; Schaile, O.; Scharff-Hansen, P.; Schenk, P.; Schieck, J.; Schmitt, S.; Schorner-Sadenius, T.; Schroder, M.; Schultz-Coulon, H.C.; Schulz, M.; Schumacher, M.; Schutz, P.; Schwick, C.; Scott, W.G.; Seuster, R.; Shears, T.G.; Shen, B.C.; Shepherd-Themistocleous, C.H.; Sherwood, P.; Siroli, G.P.; Sittler, A.; Skillman, A.; Skuja, A.; Smith, A.M.; Smith, T.J.; Snow, G.A.; Sobie, R.; Soldner-Rembold, S.; Spagnolo, S.; Spano, F.; Springer, R.W.; Sproston, M.; Stahl, A.; Steiert, M.; Stephens, K.; Steuerer, J.; Stockhausen, B.; Stoll, K.; Strom, D.; Strohmer, R.; Strumia, F.; Stumpf, L.; Surrow, B.; Szymanski, P.; Tafirout, R.; Talbot, S.D.; Tanaka, S.; Taras, P.; Tarem, S.; Taylor, R.J.; Tasevsky, M.; Teuscher, R.; Thiergen, M.; Thomas, J.; Thomson, M.A.; von Torne, E.; Torrence, E.; Towers, S.; Toya, D.; Trefzger, T.; Trigger, I.; Trocsanyi, Z.; Tsukamoto, T.; Tsur, E.; Turcot, A.S.; Turner-Watson, M.F.; Ueda, I.; Ujvari, B.; Utzat, P.; Vachon, B.; Van Kooten, R.; Vannerem, P.; Vertesi, R.; Verzocchi, M.; Vikas, P.; Vincter, M.; Vokurka, E.H.; Vollmer, C.F.; Voss, H.; Vossebeld, J.; Wackerle, F.; Wagner, A.; Waller, D.; Ward, C.P.; Ward, D.R.; Ward, J.J.; Watkins, P.M.; Watson, A.T.; Watson, N.K.; Wells, P.S.; Wengler, T.; Wermes, N.; Wetterling, D.; White, J.S.; Wilkens, B.; Wilson, G.W.; Wilson, J.A.; Wolf, G.; Wotton, S.; Wyatt, T.R.; Yamashita, S.; Yekutieli, G.; Zacek, V.; Zer-Zion, D.; Zivkovic, L.

    2013-01-01

    Electroweak measurements performed with data taken at the electron-positron collider LEP at CERN from 1995 to 2000 are reported. The combined data set considered in this report corresponds to a total luminosity of about 3~fb$^{-1}$ collected by the four LEP experiments ALEPH, DELPHI, L3 and OPAL, at centre-of-mass energies ranging from $130~GeV$ to $209~GeV$. Combining the published results of the four LEP experiments, the measurements include total and differential cross-sections in photon-pair, fermion-pair and four-fermion production, the latter resulting from both double-resonant WW and ZZ production as well as singly resonant production. Total and differential cross-sections are measured precisely, providing a stringent test of the Standard Model at centre-of-mass energies never explored before in electron-positron collisions. Final-state interaction effects in four-fermion production, such as those arising from colour reconnection and Bose-Einstein correlations between the two W decay systems arising ...

  4. Enhanced electron-positron pair production by ultra intense laser irradiating a compound target

    Science.gov (United States)

    Liu, Jian-Xun; Ma, Yan-Yun; Yu, Tong-Pu; Zhao, Jun; Yang, Xiao-Hu; Gan, Long-Fei; Zhang, Guo-Bo; Zhao, Yuan; Zhang, Shi-Jie; Liu, Jin-Jin; Zhuo, Hong-Bin; Shao, Fu-Qiu; Kawata, Shigeo

    2016-12-01

    High-energy-density electron-positron pairs play an increasingly important role in many potential applications. Here, we propose a scheme for enhanced positron production by an ultra intense laser irradiating a gas-Al compound target via the multi-photon Breit-Wheeler (BW) process. The laser pulse first ionizes the gas and interacts with a near-critical-density plasma, forming an electron bubble behind the laser pulse. A great deal of electrons are trapped and accelerated in the bubble, while the laser front hole-bores the Al target and deforms its front surface. A part of the laser wave is thus reflected by the inner curved target surface and collides with the accelerated electron bunch. Finally, a large number of γ photons are emitted in the forward direction via the Compton back-scattering process and the BW process is initiated. Dense electron-positron pairs are produced with a maximum density of 6.02× {{10}27} m-3. Simulation results show that the positron generation is greatly enhanced in the compound target, where the positron yield is two orders of magnitude greater than that in only the solid slab case. The influences of the laser intensity, gas density and length on the positron beam quality are also discussed, which demonstrates the feasibility of the scheme in practice.

  5. Ion acoustic solitary waves in plasmas with nonextensive distributed electrons, positrons and relativistic thermal ions

    Science.gov (United States)

    Hafez, M. G.; Talukder, M. R.; Sakthivel, R.

    2016-05-01

    The theoretical and numerical studies have been investigated on nonlinear propagation of weakly relativistic ion acoustic solitary waves in an unmagnetized plasma system consisting of nonextensive electrons, positrons and relativistic thermal ions. To study the characteristics of nonlinear propagation of the three-component plasma system, the reductive perturbation technique has been applied to derive the Korteweg-de Vries equation, which divulges the soliton-like solitary wave solution. The ansatz method is employed to carry out the integration of this equation. The effects of nonextensive electrons, positrons and relativistic thermal ions on phase velocity, amplitude and width of soliton and electrostatic nonlinear propagation of weakly relativistic ion acoustic solitary waves have been discussed taking different plasma parameters into consideration. The obtained results can be useful in understanding the features of small amplitude localized relativistic ion acoustic solitary waves in an unmagnetized three-component plasma system for hard thermal photon production with relativistic heavy ions collision in quark-gluon plasma as well as for astrophysical plasmas.

  6. Imprints of Electron-Positron Winds on the Multiwavelength Afterglows of Gamma-ray Bursts

    Science.gov (United States)

    Geng, J. J.; Wu, X. F.; Huang, Y. F.; Li, L.; Dai, Z. G.

    2016-07-01

    Optical rebrightenings in the afterglows of some gamma-ray bursts (GRBs) are unexpected within the framework of the simple external shock model. While it has been suggested that the central engines of some GRBs are newly born magnetars, we aim to relate the behaviors of magnetars to the optical rebrightenings. A newly born magnetar will lose its rotational energy in the form of Poynting-flux, which may be converted into a wind of electron-positron pairs through some magnetic dissipation processes. As proposed by Dai, this wind will catch up with the GRB outflow and a long-lasting reverse shock (RS) would form. By applying this scenario to GRB afterglows, we find that the RS propagating back into the electron-positron wind can lead to an observable optical rebrightening and a simultaneous X-ray plateau (or X-ray shallow decay). In our study, we select four GRBs (i.e., GRB 080413B, GRB 090426, GRB 091029, and GRB 100814A), of which the optical afterglows are well observed and show clear rebrightenings. We find that they can be well interpreted. In our scenario, the spin-down timescale of the magnetar should be slightly smaller than the peak time of the rebrightening, which can provide a clue to the characteristics of the magnetar.

  7. Intense positron beam as a source for production of electron-positron plasma

    Science.gov (United States)

    Stoneking, M. R.; Horn-Stanja, J.; Stenson, E. V.; Pedersen, T. Sunn; Saitoh, H.; Hergenhahn, U.; Niemann, H.; Paschkowski, N.; Hugenschmidt, C.; Piochacz, C.

    2016-10-01

    We aim to produce magnetically confined, short Debye length electron-positron plasma and test predicted properties for such systems. A first challenge is obtaining large numbers of positrons; a table-top experiment (system size 5 cm) with a temperature less than 5 eV requires about 1010 positrons to have more than 10 Debye lengths in the system. The NEPOMUC facility at the FRM II research reactor in Germany is one of the world's most intense positron sources. We report on characterization (using a retarding field energy analyzer with magnetic field gradient) of the NEPOMUC beam as delivered to the open beam port at various beam energies and in both the re-moderated and primary beam configurations in order to design optimal trapping (and accumulation) schemes for production of electron-positron plasma. The intensity of the re-moderated (primary) beam is in the range 2 -3 x 107 /s (1 - 5 x 108 /s). The re-moderated beam is currently the most promising for direct injection and confinement experiments; it has a parallel energy spread of 15 - 35% and the transverse energy spread is 6 - 15% of the parallel energy. We report on the implications for injection and trapping in a dipole magnetic field as well as plans for beam development, in situ re-moderation, and accumulation. We also report results demonstrating a difference in phosphor luminescent response to low energy positrons versus electrons.

  8. Properties of the electron cloud in a high-energy positron and electron storage ring

    Directory of Open Access Journals (Sweden)

    K. C. Harkay

    2003-03-01

    Full Text Available Low-energy, background electrons are ubiquitous in high-energy particle accelerators. Under certain conditions, interactions between this electron cloud and the high-energy beam can give rise to numerous effects that can seriously degrade the accelerator performance. These effects range from vacuum degradation to collective beam instabilities and emittance blowup. Although electron-cloud effects were first observed two decades ago in a few proton storage rings, they have in recent years been widely observed and intensely studied in positron and proton rings. Electron-cloud diagnostics developed at the Advanced Photon Source enabled for the first time detailed, direct characterization of the electron-cloud properties in a positron and electron storage ring. From in situ measurements of the electron flux and energy distribution at the vacuum chamber wall, electron-cloud production mechanisms and details of the beam-cloud interaction can be inferred. A significant longitudinal variation of the electron cloud is also observed, due primarily to geometrical details of the vacuum chamber. Such experimental data can be used to provide realistic limits on key input parameters in modeling efforts, leading ultimately to greater confidence in predicting electron-cloud effects in future accelerators.

  9. Towards the ultimate storage ring: The lattice design for Beijing Advanced Photon Source

    Institute of Scientific and Technical Information of China (English)

    XU Gang; JIAO Yi

    2013-01-01

    A storage ring-based light source,Beijing Advanced Photon Source (BAPS),is proposed to store a 5 GeV low-emittance electron beam and to provide high-brilliance coherent radiation.In this paper,we report our efforts of pushing down the emittance of BAPS to approach the so-called ultimate storage ring,while fixing the circumference to about 1200 m.To help deal with the challenge of beam dynamics associated with the intrinsic,very strong nonlinearities in an ultralow-emittance ring,a combination of several progressive technologies is used in the linear optics design and nonlinear optimization,such as a modified theoretical minimum emittance cell with smallaperture magnets,quasi-3rd-order achromat,theoretical analyzer based on Lie Algebra and Hamiltonian analysis,multi-objective genetic algorithm and frequency map analysis.These technologies enable us to obtain satisfactory beam dynamics in one lattice design with natural emittance of 75 pm.

  10. Diffraction-limited storage rings - a window to the science of tomorrow.

    Science.gov (United States)

    Eriksson, Mikael; van der Veen, J Friso; Quitmann, Christoph

    2014-09-01

    This article summarizes the contributions in this special issue on Diffraction-Limited Storage Rings. It analyses the progress in accelerator technology enabling a significant increase in brightness and coherent fraction of the X-ray light provided by storage rings. With MAX IV and Sirius there are two facilities under construction that already exploit these advantages. Several other projects are in the design stage and these will probably enhance the performance further. To translate the progress in light source quality into new science requires similar progress in aspects such as optics, beamline technology, detectors and data analysis. The quality of new science will be limited by the weakest component in this value chain. Breakthroughs can be expected in high-resolution imaging, microscopy and spectroscopy. These techniques are relevant for many fields of science; for example, for the fundamental understanding of the properties of correlated electron materials, the development and characterization of materials for data and energy storage, environmental applications and bio-medicine.

  11. Vacuum chamber with distributed titanium sublimation pumping for the G-line wiggler at Cornell High Energy Synchrotron Source

    Science.gov (United States)

    Li, Y.; He, Y.; Mistry, N. B.

    2003-07-01

    This article describes a 3-m-long vacuum chamber for the new wiggler magnet at the Cornell Electron Storage Ring (CESR) for the synchrotron light beam line of the Cornell High Energy Synchrotron Source (CHESS). Copper was chosen as the main chamber material for its good electric and thermal conductivities. Proper mechanical design and welding procedure were implemented to meet very tight tolerances to ensure adequate vertical aperture for the stored beams in CESR while allowing the required small wiggler gap. Distributed titanium sublimation pumping is incorporated along the 3 m length of the chamber to provide sufficient pumping speed and capacity for CESR and CHESS operations. The chamber pumping performance was evaluated prior to installation. Linear distributed pumping speeds at the beam line of ~720 l/s/m for N2 and CO and ~4000 l/s/m for H2 were measured. The measured pumping capacities for N2, CO and H2 are ~1.0, ~2.0 and ~77 Torr l, respectively, for each titanium sublimation cycle. Measurements also showed that CO molecules adsorb on the N2 and H2 saturated titanium films with virtually the same initial sticking coefficient as on a fresh titanium film. Analyses indicated very different CO adsorption mechanisms between the N2 and H2 saturated titanium films. While the replacement of surface H2 by CO was observed, little desorption of nitrogen was measured. Operational experience showed excellent vacuum pumping performance over two years after the chamber installation.

  12. THE POTENTIAL FOR NEUTRINO PHYSICS AT MUON COLLIDERS AND DEDICATED HIGH CURRENT MUON STORAGE RINGS

    Energy Technology Data Exchange (ETDEWEB)

    BIGI,I.; BOLTON,T.; FORMAGGIO,J.; HARRIS,D.; MORFIN,J.; SPENTZOURIS,P.; YU,J.; KAYSER,B.; KING,B.J.; MCFARLAND,K.; PETROV,A.; SCHELLMAN,H.; VELASCO,M.; SHROCK,R.

    2000-05-11

    Conceptual design studies are underway for both muon colliders and high-current non-colliding muon storage rings that have the potential to become the first true neutrino factories. Muon decays in long straight sections of the storage rings would produce uniquely intense and precisely characterized two-component neutrino beams--muon neutrinos plus electron antineutrinos from negative muon decays and electron neutrinos plus muon antineutrinos from positive muons. This article presents a long-term overview of the prospects for these facilities to greatly extend the capabilities for accelerator-based neutrino physics studies for both high rate and long baseline neutrino experiments. As the first major physics topic, recent experimental results involving neutrino oscillations have motivated a vigorous design effort towards dedicated neutrino factories that would store muon beams of energies 50 GeV or below. These facilities hold the promise of neutrino oscillation experiments with baselines up to intercontinental distances and utilizing well understood beams that contain, for the first time, a substantial component of multi-GeV electron-flavored neutrinos. In deference to the active and fast-moving nature of neutrino oscillation studies, the discussion of long baseline physics at neutrino factories has been limited to a concise general overview of the relevant theory, detector technologies, beam properties, experimental goals and potential physics capabilities. The remainder of the article is devoted to the complementary high rate neutrino experiments that would study neutrino-nucleon and neutrino-electron scattering and would be performed at high performance detectors placed as close as is practical to the neutrino production straight section of muon storage rings in order to exploit beams with transverse dimensions as small as a few tens of centimeters.

  13. Proposal of a relationship between dynamic aperture adn intensity evolution in a storage ring

    CERN Document Server

    Giovannozzi, M

    2010-01-01

    A scaling law for the time-dependence of the dynamic aperture, i.e., the region of phase space where stable motion occurs, was proposed in previous papers, about ten years ago. The use of fundamental theorems of the theory of dynamical systems allowed showing that the dynamic aperture has a logarithmic dependence on time. In this paper this result, proved by mean of numerical simulations, is used as a basis for deriving a scaling law for the intensity evolution in a storage ring. The proposed scaling law is also tested against experimental data showing a remarkable agreement.

  14. Safe operating conditions for NSLS-II Storage Ring Frontends commissioning

    Energy Technology Data Exchange (ETDEWEB)

    Seletskiy, S. [Brookhaven National Lab. (BNL), Upton, NY (United States); Amundsen, C. [Brookhaven National Lab. (BNL), Upton, NY (United States); Ha, K. [Brookhaven National Lab. (BNL), Upton, NY (United States); Hussein, A. [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2015-04-02

    The NSLS-II Storage Ring Frontends are designed to safely accept the synchrotron radiation fan produced by respective insertion device when the electron beam orbit through the ID is locked inside the predefined Active Interlock Envelope. The Active Interlock is getting enabled at a particular beam current known as AI safe current limit. Below such current the beam orbit can be anywhere within the limits of the SR beam acceptance. During the FE commissioning the beam orbit is getting intentionally disturbed in the particular ID. In this paper we explore safe operating conditions for the Frontends commissioning.

  15. Commissioning and Early Operation Experience of the NSLS-II Storage Ring RF System

    Energy Technology Data Exchange (ETDEWEB)

    Gao, F.; Rose, J.; Cupolo, J.; Dilgen, T.; Rose, B.; Gash, W.; Ravindranath, V.; Yeddulla, M.; Papu, J.; Davila, P.; Holub, B.; Tagger, J.; Sikora, R.; Ramirez, G.; Kulpin, J.

    2015-05-03

    The National Synchrotron Light Source II (NSLS-II) is a 3 GeV electron X-ray user facility commissioned in 2014. The storage ring RF system, essential for replenishing energy loss per turn of the electrons, consists of digital low level RF controllers, 310 kW CW klystron transmitters, CESR-B type superconducting cavities, as well as a supporting cryogenic system. Here we will report on RF commissioning and early operation experience of the system for beam current up to 200mA.

  16. Intensity interferometry of single x-ray pulses from a synchrotron storage ring

    CERN Document Server

    Singer, A; Marras, A; Klyuev, A; Becker, J; Schlage, K; Skopintsev, P; Gorobtsov, O; Shabalin, A; Wille, H -C; Franz, H; Graafsma, H; Vartanyants, I A

    2014-01-01

    We report on measurements of second-order intensity correlations at the high brilliance storage ring PETRA III using a prototype of the newly developed Adaptive Gain Integrating Pixel Detector (AGIPD). The detector recorded individual synchrotron radiation pulses with an x-ray photon energy of 14.4 keV and repetition rate of about 5 MHz. The second-order intensity correlation function was measured simultaneously at different spatial separations that allowed to determine the transverse coherence length at these x-ray energies. The measured values are in a good agreement with theoretical simulations based on the Gaussian Schell-model.

  17. Th.P-19. Collisional effects and dynamic aperture in high-intensity storage rings

    Energy Technology Data Exchange (ETDEWEB)

    Benedetti, C. [Dipartimento di Fisica Universita di Bologna and INFN, Via Irnerio 46, Bologna 40126 (Italy)]. E-mail: benedetti@bo.infn.it; Rambaldi, S. [Dipartimento di Fisica Universita di Bologna and INFN, Via Irnerio 46, Bologna 40126 (Italy); Turchetti, G. [Dipartimento di Fisica Universita di Bologna and INFN, Via Irnerio 46, Bologna 40126 (Italy)

    2005-05-21

    We analyze the dynamic aperture in the presence of strong sextupolar errors for a high-intensity beam. The scaling laws for the short-term dynamic aperture are examined and its dependence on the perveance is discussed in a mean field approximation for a coasting beam. The collisional effects of Coulombian interaction are estimated for a linear lattice using a scaling law for the relaxation time. The collisional effects on the long-time dynamic aperture are discussed by comparing the results of full Hamiltonian integration with a mean field theory. An application to a storage ring with the HIDIF parameters is briefly outlined.

  18. Study of closed orbit response to magnet vibrations at the SSRF storage ring

    Institute of Scientific and Technical Information of China (English)

    CHEN Jian-Hui; ZHAO Zhen-Tang; DAI Zhi-Min; LIU Gui-Min

    2008-01-01

    This paper presents the analytical and simulation responses of the closed orbit distortion in the SSRF storage ring to random and plane wave like magnet vibrations respectively. It is shown that the use of girder is very beneficial in the view of suppressing this response function. Effect of the independently supported gradient bending magnets to the closed orbit response is given. An analytic formula is written to give a rough estimate of the closed orbit distortion due to ground motion, taking into account the closed orbit response function and girder transfer function. As an example, the result of SSRF case is given.

  19. An MDM Spin Transparent Quadrupole for Storage Ring based EDM Search

    CERN Document Server

    Bai, Mei; Sagan, David

    2016-01-01

    A storage ring provides an attractive option for directly measuring the electric dipole moment~(EDM) of charged particles. To reach a sensitivity of 10^-29 e x cm, it is critical to mitigate the systematic errors from all sources. This daunting task is pushing the precision frontier of accelerator science and technology beyond its current state of the art. Here, we present a unique idea of a magnetic dipole moment~(MDM) spin transparent quadrupole that can significantly reduce the systematic errors due to the transverse electric and magnetic fields that particle encounters.

  20. Linear optics calibration and nonlinear optimization during the commissioning of the SSRF storage ring

    Institute of Scientific and Technical Information of China (English)

    TIAN Shun-Qiang; ZHANG Wen-Zhi; LI Hao-Hu; ZHANG Man-Zhou; HOU Jie; ZHOU xue-Mei; LIU Gui-Min

    2009-01-01

    Phase Ⅰ commissioning of the SSRF storage ring on 3.0 GeV beam energy was started at the end of December 2007.A lot of encouraging results have been obtained so far.In this paper,calibrations of the linear optics during the commissioning are discussed,and some measured results about the nonlinearity given.Calibration procedure emphasizes correcting quadrupole magnetic coefficients with the Linear Optics from Closed Orbit(LOCO)technique.After fitting the closed orbit response matrix,the linear optics of the four test modes is substantially corrected,and the measured physical parameters agree well with the designed ones.

  1. Proposal to detect an emission of unusual super-high energy electrons in electron storage rings

    Directory of Open Access Journals (Sweden)

    Da-peng Qian

    2014-01-01

    Full Text Available According to an extended Lorentz–Einstein mass formula taken into the uncertainty principle, it is predicted that the electron beams passing accelerating electric field should with a small probability generate abnormal super-high energy electrons which are much higher than the beam energy. Author’s preliminary experiment result at electron storage ring has hinted these signs, so suggests to more strictly detect this unusual phenomenon, and thus to test the extended mass formula as well as a more perfect special relativity.

  2. Addenda to General Spin Precession and Betatron Oscillation in Storage Ring

    CERN Document Server

    Fukuyama, Takeshi

    2016-01-01

    We give the geralized expression of spin precession of extended bunch particles having both anomalous magnetic and electric dipole moments in storage ring in higher order than the previous work and in the presence of ${\\bf E}$ field as well as ${\\bf B}$ field. These addenda are essential since some experiments consider the focusing field in the second order of the beam extent and in the presence of both ${\\bf B}$ and ${\\bf E}$ fields . It is shown that some focusing fields with constant magnitude of the velocity considered in many literatures lead to the violation of self consistency.

  3. Characteristics of the Duke/OK-4 storage ring FEL and gamma-ray source

    Science.gov (United States)

    Park, Seong Hee

    The Duke/OK-4 storage ring is a dedicated device for driving a short wavelength Free Electron Laser (FEL). In addition, Compton scattering of the laser light from the circulating electron beam products a semi-monochromatic γ-ray source. The dynamics of such a system including accelerator physics, FEL physics, and Compton backscattering is complex and requires special study, This dissertation is a detailed theoretical and experimental analysis of such a system. The main emphasis of the theory presented here is the self-consistent analysis of the system which incorporates three drastically different processes-the dynamics of an intense electron beam, the free electron laser, and the Compton backscattering. The interdependence of these three processes and the physics of this complex system is discussed in this work. The OK-4/Duke storage ring FEL is the only accelerator facility capable of routine lasing in the deep-UV range and able to generate intense γ-ray beams with energy tunable from 2 MeV to 55 MeV, with energy resolution between 0.5%-1% and with flux up to -5 × 107. The flexibility of this γ-ray source is due to the record-breaking performance of the OK-4/Duke storage ring FEL (lasing from 193.7 nm to 730 nm). Experimental studies determining the parameters of the electron beams, OK-4 FEL beams, and γ-ray beams compare favorably with the theoretical predictions. This study confirms that the electron energy spread induced by FEL lasing is currently the main factor limiting energy resolution. These results provide a solid foundation for future development of the system to obtain more reliable predictions of its performance. A number of useful ``scaling laws'' are also presented here. The results of this work have provided the basis for a number of applications of the OK-4 FEL beam and γ- ray beam that are underway or in the advance planning stage. Future plans include the development and design of a system capable of generating γ-ray beams with an energy

  4. Rf stability, control and bunch lengthening in electron synchrotron storage rings

    Energy Technology Data Exchange (ETDEWEB)

    Wachtel, J.M.

    1989-09-01

    A self-consistent theory for nonlinear longitudinal particle motion and rf cavity excitation in a high energy electron storage ring is developed. Coupled first order equations for the motion of an arbitrary number of particles and for the field in several rf cavities are given in the form used in control system theory. Stochastic quantum excitation of synchrotron motion is included, as are the effects of rf control system corrections. Results of computations for double cavity bunch lengthening are given. 11 refs., 4 figs., 1 tab.

  5. Probing the violation of equivalence principle at a muon storage ring via neutrino oscillation

    CERN Document Server

    Datta, A

    2001-01-01

    We examine the possible tests of violation of the gravitational equivalence principle (VEP) at a muon storage ring via neutrino oscillation experiments. If different neutrino flavours couple to the gravitational potential with different strength, flavour eigenstates are no longer the gravitational interaction eigenstates. This leads to the neutrino oscillation. If one starts with $\\mu ^+$ beam then appearance of $\\tau ^\\pm$, $e ^+$ and $\\mu ^-$ in the final state are the signals for neutrino oscillation. We have estimated the number of $\\mu ^-$ and $\\tau^+$ events in this scenario in $\

  6. Design of the beam transport line and injection system of the compact storage ring for TTX

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    In this article, we present the design of the beam transport line and injection system of the compact storage ring for the Tsinghua Thomson scattering X-ray (TTX) source. The layout of the beam transport line fits in with the limited available space. The injection system is simplified, consisting of only one single kicker; the stray field on the reference orbit is also reduced without the septum magnet. We choose a travelling wave kicker and present both 2D and 3D simulations for the structure design.

  7. Feedback Damping of a Coherent Instability at Small-Laser Equipped Storage Ring, S-LSR

    Science.gov (United States)

    Fujimoto, Shinji; Shirai, Toshiyuki; Noda, Akira; Ikegami, Masahiro; Tongu, Hiromu; Noda, Koji

    2006-12-01

    A beam test for the feedback damping of a coherent instability at small-laser equipped storage ring (S-LSR) was carried out. The instability caused beam loss, which limited the stored beam current to be about 600 μA during beam stacking with electron cooling. A vertical feedback damping system (VFS) using an electro-static beam position monitor (ESBPM) and a vertical kicker was applied to suppress this beam instability. The VFS realized not only suppressing the vertical coherent instability, but also revealing the characteristics of the feedback damping.

  8. Recent Results and Progress on Leptonic and Storage Ring EDM Searches

    Science.gov (United States)

    Kawall, David

    2016-02-01

    The Standard Model is incomplete and unable to explain the matter-antimatter asymmetry in the universe. Many extensions of the Standard Model predict new particles and interactions with additional CP-violating phases that can explain this imbalance. Electric dipole moments (EDMs) of fundamental particles, which are generated by CP-violating interactions, can be enhanced by many orders of magnitude by contributions from this new physics to a magnitude within reach of current and planned experiments. New approaches to EDM searches using storage rings, and their sensitivity to new physics are presented.

  9. Restriction on the energy and luminosity of e(+)e(-) storage rings due to beamstrahlung.

    Science.gov (United States)

    Telnov, V I

    2013-03-15

    The role of beamstrahlung in high-energy e(+)e(-) storage-ring colliders (SRCs) is examined. Particle loss due to the emission of single energetic beamstrahlung photons is shown to impose a fundamental limit on SRC luminosities at energies 2E(0)≳140  GeV for head-on collisions and 2E(0)≳40  GeV for crab-waist collisions. With beamstrahlung taken into account, we explore the viability of SRCs in the 2E(0)=240-500   GeV range, which is of interest in the precision study of the Higgs boson. At 2E(0)=240  GeV, SRCs are found to be competitive with linear colliders; however, at 2E(0)=400-500  GeV, the attainable SRC luminosity would be a factor 15-25 smaller than desired.

  10. A PULSED MODULATOR POWER SUPPLY FOR THE G-2 MUON STORAGE RING INJECTION KICKER.

    Energy Technology Data Exchange (ETDEWEB)

    MI,J.LEE,Y.Y.MORSE,W.M.PAI,C.I.PAPPAS,G.C.SANDERS,Y.SEMERTIZIDIS,Y.,ET AL.

    2003-03-01

    This paper describes the pulse modulator power supplies used to drive the kicker magnets that inject the muon beam into the 8-2 storage ring that has been built at Brookhaven National Laboratory. Three modulators built into coaxial structures consisting of a series circuit of an energy storage capacitor, a damping resistor and a fast thyratron switch are used to energize three magnets that kick the beam into the proper orbit. A 100 kV charging power supply is used to charge the capacitor to 95kV. The damping resistor shapes the magnet current waveform to a 450 nanosecond half-sine to match the injection requirements. This paper discusses the modulator design, construction and operation.

  11. The HERMES Polarized Hydrogen and Deuterium Gas Target in the HERA Electron Storage Ring

    CERN Document Server

    Airapetian, A; Akopov, Z; Amarian, M; Ammosov, V V; Andrus, A; Aschenauer, E C; Augustyniak, W; Avakian, R; Avetisian, A; Avetissian, E; Bailey, P; Baturin, V; Baumgarten, C; Beckmann, M; Belostotskii, S; Bernreuther, S; Bianchi, N; Blok, H P; Böttcher, Helmut B; Borisov, A; Bouwhuis, M; Brack, J; Brüll, A; Bryzgalov, V V; Capitani, G P; Chiang, H C; Ciullo, G; Contalbrigo, M; Dalpiaz, P F; De Leo, R; De Nardo, L; De Sanctis, E; Devitsin, E G; Di Nezza, P; Düren, M; Ehrenfried, M; Elalaoui-Moulay, A; Elbakian, G M; Ellinghaus, F; Elschenbroich, U; Ely, J; Fabbri, R; Fantoni, A; Feshchenko, A; Felawka, L; Fox, B; Franz, J; Frullani, S; Gärber, Y; Gapienko, G; Gapienko, V; Garibaldi, F; Garrow, K; Garutti, E; Gaskell, D; Gavrilov, G E; Karibian, V; Graw, G; Grebenyuk, O; Greeniaus, L G; Hafidi, K; Hartig, M; Hasch, D; Heesbeen, D; Henoch, M; Hertenberger, R; Hesselink, W H A; Hillenbrand, A; Hoek, M; Holler, Y; Hommez, B; Iarygin, G; Ivanilov, A; Izotov, A; Jackson, H E; Jgoun, A; Kaiser, R; Kinney, E; Kiselev, A; Königsmann, K C; Kopytin, M; Korotkov, V A; Kozlov, V; Krauss, B; Krivokhizhin, V G; Lagamba, L; Lapikas, L; Laziev, A; Lenisa, P; Liebing, P; Lindemann, T; Lipka, K; Lorenzon, W; Lü, J; Maiheu, B; Makins, N C R; Marianski, B; Marukyan, H O; Masoli, F; Mexner, V; Meyners, N; Miklukho, O; Miller, C A; Miyachi, Y; Muccifora, V; Nagaitsev, A; Nappi, E; Naryshkin, Yu; Nass, A; Negodaev, M A; Nowak, Wolf-Dieter; Oganessyan, K; Ohsuga, H; Orlandi, G; Pickert, N; Potashov, S Yu; Potterveld, D H; Raithel, M; Reggiani, D; Reimer, P E; Reischl, A; Reolon, A R; Riedl, C; Rith, K; Rosner, G; Rostomyan, A; Rubacek, L; Ryckbosch, D; Salomatin, Yu I; Sanjiev, I; Savin, I; Scarlett, C; Schäfer, A; Schill, C; Schnell, G; Schüler, K P; Schwind, A; Seele, J; Seidl, R; Seitz, B; Shanidze, R G; Shearer, C; Shibata, T A; Shutov, V B; Simani, M C; Sinram, K; Stancari, M D; Statera, M; Steffens, E; Steijger, J J M; Stewart, J; Stösslein, U; Tait, P; Tanaka, H; Taroian, S P; Tchuiko, B; Terkulov, A R; Tkabladze, A V; Trzcinski, A; Tytgat, M; Vandenbroucke, A; Van der Nat, P B; van der Steenhoven, G; Vetterli, Martin C; Vikhrov, V; Vincter, M G; Visser, J; Vogel, C; Vogt, M; Volmer, J; Weiskopf, C; Wendland, J; Wilbert, J; Ybeles-Smit, G V; Yen, S; Zihlmann, B; Zohrabyan, H G; Zupranski, P

    2004-01-01

    The HERMES hydrogen and deuterium nuclear-polarized gas targets have been in use since 1996 with the polarized electron beam of HERA at DESY to study the spin structure of the nucleon. Polarized atoms from a Stern-Gerlach Atomic Beam Source are injected into a storage cell internal to the HERA electron ring. Atoms diffusing from the center of the storage cell into a side tube are analyzed to determine the atomic fraction and the atomic polarizations. The atoms have a nuclear polarization, the axis of which is defined by an external magnetic holding field. The holding field was longitudinal during 1996-2000, and was changed to transverse in 2001. The design of the target is described, the method for analyzing the target polarization is outlined, and the performance of the target in the various running periods is presented.

  12. High-energy recollision processes of laser-generated electron-positron pairs

    CERN Document Server

    Meuren, Sebastian; Keitel, Christoph H; Di Piazza, Antonino

    2014-01-01

    Two oppositely-charged particles created within a microscopic space-time region can be separated, accelerated and brought to a recollision by a laser field. Consequently, new reactions become feasible, where the energy absorbed by the particles is efficiently released. By investigating the laser-dressed polarization operator, we identify a new contribution describing high-energy recollisions experienced by an electron-positron pair generated when a gamma photon impinges on an intense, linearly-polarized laser pulse. The energy absorbed in the recollision process corresponds to a large number of laser photons and can be exploited to prime high-energy reactions. As an example, we show that the inclusion of the recollision process substantially alters -- both qualitatively and quantitatively -- the tree-level muon--anti-muon photoproduction probability. In particular, the absence of an exponential suppression factor in the recollision contribution results in an enhancement of the production probability by severa...

  13. Electron-positron Colliders from the $\\phi$ to the Z report

    CERN Document Server

    Zhao, Z; Burdman, G; Marciano, W; Hitlin, D; Mandelkern, M A; Soffer, A; Cassel, David G; Gibbons, L; Mönig, K; Butler, J; Kasper, P; Kutschke, R; MacKenzie, P B; Pordes, S; Ray, R; Sen, T; Bettoni, D; Calabrese, R; Bloise, C; Kaplan, D; Katayama, N; Okada, Y; Ohnishi, Y; Yamamoto, H; Gritsan, A; Dytman, S A; Lee, J; Shipsey, I; Maravin, Y; Decker, Franz Josef; Hiller, G; Kim, P; Leith, D W G S; Petrak, S; Robertson, S; Roodman, A; Seeman, J; Artuso, M; Stone, S; Lou, X; Luke, M; Johns, W

    2001-01-01

    We report on the status and plans of experiments now running or proposed for electron-positron colliders at energies between the $\\phi$ and the Z. The $e^{+}e^{-}$ B and charm factories we considered were PEP-II/BABAR, KEKB/Belle, superKEK, SuperBABAR, and CESR-c/CLEO-c. We reviewed the programs at the $\\phi$ factory at Frascati and the proposed PEP-N facility at Stanford Linear Accelerator Center. We studied the prospects for B physics with a dedicated linear collider Z factory, associated with the TESLA high energy linear collider. In all cases, we compared the physics reach of these facilities with that of alternative experiments at hadron colliders or fixed target facilities.

  14. Nonlinear interaction of intense electromagnetic waves with a magnetoactive electron-positron-ion plasma

    Energy Technology Data Exchange (ETDEWEB)

    Khorashadizadeh, S. M.; Rastbood, E.; Zeinaddini Meymand, H. [Physics Department, University of Birjand, Birjand (Iran, Islamic Republic of); Niknam, A. R. [Laser and Plasma Research Institute, Shahid Beheshti University, G.C., Tehran (Iran, Islamic Republic of)

    2013-08-15

    The nonlinear coupling between circularly polarized electromagnetic (CPEM) waves and acoustic-like waves in a magnetoactive electron-positron-ion (e-p-i) plasma is studied, taking into account the relativistic motion of electrons and positrons. The possibility of modulational instability and its growth rate as well as the envelope soliton formation and its characteristics in such plasmas are investigated. It is found that the growth rate of modulation instability increases in the case that ω{sub c}/ω<1 (ω{sub c} and ω are the electron gyrofrequency and the CPEM wave frequency, respectively) and decreases in the case that ω{sub c}/ω>1. It is also shown that in a magnetoactive e-p-i plasma, the width of bright soliton increases/decreases in case of (ω{sub c}/ω)<1/(ω{sub c}/ω)>1 by increasing the magnetic field strength.

  15. Multiplicity distributions in proton-(anti)proton and electron-positron collisions with parton recombination

    CERN Document Server

    Zborovský, I

    2011-01-01

    A new approach to phenomenological description of the charged particle multiplicity distributions in proton-(anti)proton and electron-positron collisions is presented. The observed features of the data are interpreted on the basis of stochastic-physical ideas of multiple production. Besides the processes of parton immigration and absorption, two and three patron incremental and decremental recombinations are considered. The complex behaviour of the multiplicity distributions at different energies is described by four parametric generalized hypergeometric distribution (GHD). Application of the proposed GHD to data measured by the CMS, ALICE, and ATLAS Collaborations suggests that soft multiparton recombination processes can manifest itself significantly in the structure of multiplicity distribution in pp interactions at very high energies.

  16. Electron-positron pair production in external electric fields varying both in space and time

    Science.gov (United States)

    Aleksandrov, I. A.; Plunien, G.; Shabaev, V. M.

    2016-09-01

    The Schwinger mechanism of electron-positron pair production in the presence of strong external electric fields is analyzed numerically for the case of one- and two-dimensional field configurations where the external field depends both on time and one spatial coordinate. In order to provide this analysis, a new efficient numerical approach is developed. The number of particles created is obtained numerically and also compared with the analytical results for several exactly solvable one-dimensional backgrounds. For the case of two-dimensional field configurations the effects of the spatial finiteness are examined, which confirms their importance and helps us to attest our approach further. The corresponding calculations are also performed for several more interesting and nontrivial combinations of temporal and spatial inhomogeneities. Finally, we discuss the case of a spatially periodic external field when the approach is particularly productive. The method employed is described in detail.

  17. Oscillating two-stream instability in a magnetized electron-positron-ion plasma

    Energy Technology Data Exchange (ETDEWEB)

    Tinakiche, Nouara [Department of Physics, Faculty of Science, U.M.B.B, Boumerdes 35000 (Algeria); Faculty of Physics, U.S.T.H.B, Algiers 16111 (Algeria); Annou, R. [Faculty of Physics, U.S.T.H.B, Algiers 16111 (Algeria)

    2015-04-15

    Oscillating two-stream instability (OTSI) in a magnetized electron-ion plasma has been thoroughly studied, e.g., in ionospheric heating experiments [C. S. Liu and V. K. Tripathi, Interaction of Electromagnetic Waves With Electron Beams and Plasmas (World Scientific, 1994); V. K. Tripathi and P. V. Siva Rama Prasad, J. Plasma Phys. 41, 13 (1989); K. Ramachandran and V. K. Tripathi, IEEE Trans. Plasma Sci. 25, 423 (1997)]. In this paper, OTSI is investigated in a magnetized electron-positron-ion plasma. The dispersion relation of the process is established. The pump field threshold, along with the maximum growth rate of the instability is assessed using the Arecibo and HAARP parameters.

  18. Oscillating two-stream instability in a magnetized electron-positron-ion plasma

    Science.gov (United States)

    Tinakiche, Nouara; Annou, R.

    2015-04-01

    Oscillating two-stream instability (OTSI) in a magnetized electron-ion plasma has been thoroughly studied, e.g., in ionospheric heating experiments [C. S. Liu and V. K. Tripathi, Interaction of Electromagnetic Waves With Electron Beams and Plasmas (World Scientific, 1994); V. K. Tripathi and P. V. Siva Rama Prasad, J. Plasma Phys. 41, 13 (1989); K. Ramachandran and V. K. Tripathi, IEEE Trans. Plasma Sci. 25, 423 (1997)]. In this paper, OTSI is investigated in a magnetized electron-positron-ion plasma. The dispersion relation of the process is established. The pump field threshold, along with the maximum growth rate of the instability is assessed using the Arecibo and HAARP parameters.

  19. Small amplitude Kinetic Alfven waves in a superthermal electron-positron-ion plasma

    Science.gov (United States)

    Adnan, Muhammad; Mahmood, Sahahzad; Qamar, Anisa; Tribeche, Mouloud

    2016-11-01

    We are investigating the propagating properties of coupled Kinetic Alfven-acoustic waves in a low beta plasma having superthermal electrons and positrons. Using the standard reductive perturbation method, a nonlinear Korteweg-de Vries (KdV) type equation is derived which describes the evolution of Kinetic Alfven waves. It is found that nonlinearity and Larmor radius effects can compromise and give rise to solitary structures. The parametric role of superthermality and positron content on the characteristics of solitary wave structures is also investigated. It is found that only sub-Alfvenic and compressive solitons are supported in the present model. The present study may find applications in a low β electron-positron-ion plasma having superthermal electrons and positrons.

  20. Semiclassical description of nonlinear electron-positron photoproduction in strong laser fields

    CERN Document Server

    Meuren, Sebastian; Di Piazza, Antonino

    2015-01-01

    The nonlinear Breit-Wheeler process is studied in the presence of strong and short laser pulses. We show that for a relativistically intense plane-wave laser field many aspects of the momentum distribution for the produced electron-positron pair like its extend, region of highest probability and carrier-envelope phase effects can be explained from the classical evolution of the created particles in the background field. To this end we verify that the local constant-crossed field approximation is also appropriate for the calculation of the spectrum if applied on the probability-amplitude level. To compare the exact expressions with the semiclassical approach, we introduce a very fast numerical scheme, which makes it feasible to completely resolve the interference structure of the spectrum over the available multidimensional phase space.

  1. Minimal left-right symmetric models and new $Z'$ properties at future electron-positron colliders

    CERN Document Server

    Almeida, F M L; Martins-Simões, J A; Ponciano, J; Ramalho, A J; Wulck, S; Do Vale, M A B; Wulck, Stenio

    2004-01-01

    It was recently shown that left-right symmetric models for elementary particles can be built with only two Higgs doublets. The general consequence of these models is that the left and right fermionic sectors can be connected by a new neutral gauge boson $Z'$ having its mass as the only additional new parameter. In this paper we study the influence of the fundamental fermionic representation for this new neutral gauge boson. Signals of possible new heavy neutral gauge bosons are investigated for the future electron-positron colliders at $\\sqrt s = 500$ GeV, 1 TeV and 3 TeV. The total cross sections, forward-backward and left-right asymmetries and model differences are calculated for the process $e^+ e^- \\longrightarrow \\mu^+ \\mu^-$. Bounds on $Z'$ masses are estimated.

  2. Electron-positron pair creation in low-energy collisions of heavy bare nuclei

    CERN Document Server

    Maltsev, I A; Tupitsyn, I I; Bondarev, A I; Kozhedub, Y S; Plunien, G; Stoehlker, Th

    2014-01-01

    A new method for calculations of electron-positron pair-creation probabilities in low-energy heavy-ion collisions is developed. The approach is based on the propagation of all one-electron states via the numerical solving of the time-dependent Dirac equation in the monopole approximation. The electron wave functions are represented as finite sums of basis functions constructed from B-splines using the dual-kinetic-balance technique. The calculations of the created particle numbers and the positron energy spectra are performed for the collisions of bare nuclei at the energies near the Coulomb barrier with the Rutherford trajectory and for different values of the nuclear charge and the impact parameter. To examine the role of the spontaneous pair creation the collisions with a modified velocity and with a time delay are also considered. The obtained results are compared with the previous calculations and the possibility of observation of the spontaneous pair creation is discussed.

  3. INTEGRAL/SPI Observations of Electron-Positron Annihilation Radiation from our Galaxy

    Science.gov (United States)

    Teegarden, B. J.; Watanabe, K.; Knoedlseder, J.; Jean, P.; Lonjou, V.; Weidenspointner, G.; Skinner, G.; von Ballmoos, P.; Vedrenne, G.; Roques, J.-P.; Schanne, S.; Schoenfelder, V.

    2004-12-01

    The spectrometer on INTEGRAL (SPI) is a coded-aperture gamma-ray telescope with moderate angular resolution (3 deg) and superior energy resolution (2 keV at 511 keV). One of it's principal science goals is the detailed study of 511 keV electron-positron annihilation from our Galaxy. The origin of this radiation remains a mystery, however current morphological studies suggest an older stellar population. There has also been recent speculation on the possibility of the existence of light (< 100 MeV) dark matter particles whose annihilation or decay could produce the observed 511 keV emission. In this paper we summarize the current results from SPI, compare them with previous results and discuss their implication on possible models for the production of the annihilation radiation. INTEGRAL is a project of ESA. This work was supported by NASA and CNES.

  4. Bound-Free Electron-Positron Pair Production in Relativistic Heavy-Ion Collisions

    CERN Document Server

    Sengul, M Y; Fritzsche, S

    2009-01-01

    The bound-free electron-positron pair production is considered for relativistic heavy ion collisions. In particular, cross sections are calculated for the pair production with the simultaneous capture of the electron into the 1s ground state of one of the ions and for energies that are relevant for the Relativistic Heavy Ion Collider (RHIC) and the Large Hadron Colliders (LHC). In the framework of perturbation theory, we applied Monte-Carlo integration techniques to compute the lowest-order Feynman diagrams amplitudes by using Darwin wave functions for the bound states of the elec- trons and Sommerfeld-Maue wave functions for the continuum states of the positrons. Calculations were performed especially for the collision of Au + Au at 100 GeV/nucleon and Pb + Pb at 3400 GeV/nucleon.

  5. Closure Relations for Electron-Positron Pair-Signatures in Gamma-Ray Bursts

    CERN Document Server

    Murase, Kohta

    2007-01-01

    We present recipes to diagnose the fireball of gamma-ray bursts (GRBs) by combining observations of electron-positron pair-signatures (the pair-annihilation line and the cutoff energy due to the pair-creation process). Our recipes are largely model-independent and extract information even from the non-detection of either pair-signature. We evaluate physical quantities such as the Lorentz factor, optical depth and pair-to-baryon ratio, only from the observable quantities. In particular, we can test whether prompt emission of GRBs comes from the pair/baryonic photosphere or not. The future-coming Gamma-Ray Large Area Space Telescope (GLAST) satellite will provide us with good chances to use our recipes by detecting pair-signatures.

  6. Planar dust-acoustic waves in electron-positron-ion-dust plasmas with dust size distribution

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Hong-Yan; Zhang, Kai-Biao [Sichuan University of Science and Engineering, Zigong (China)

    2014-06-15

    Nonlinear dust-acoustic solitary waves which are described with a Kortweg-de vries (KdV) equation by using the reductive perturbation method, are investigated in a planar unmagnetized dusty plasma consisting of electrons, positrons, ions and negatively-charged dust particles of different sizes and masses. The effects of the power-law distribution of dust and other plasma parameters on the dust-acoustic solitary waves are studied. Numerical results show that the dust size distribution has a significant influence on the propagation properties of dust-acoustic solitons. The amplitudes of solitary waves in the case of a power-law distribution is observed to be smaller, but the soliton velocity and width are observed to be larger, than those of mono-sized dust grains with an average dust size. Our results indicate that only compressed solitary waves exist in dusty plasma with different dust species. The relevance of the present investigation to interstellar clouds is discussed.

  7. INTEGRAL/SPI Limits on Electron-Positron Annihilation Radiation from the Galactic Plane

    CERN Document Server

    Teegarden, B J; Jean, P; Knödlseder, J; Lonjou, V; Roques, J P; Skinner, G K; Von Ballmoos, P; Weidenspointner, G; Bazzano, A; Butt, Y M; Decourchelle, A; Fabian, A C; Goldwurm, A; Güdel, M; Hannikainen, D C; Hartmann, D H; Hornstrup, A; Lewin, W H G; Makishima, K; Malzac, A; Miller, J; Parmar, A N; Reynolds, S P; Rothschild, R E; Tomsick, J A; Vink, J

    2004-01-01

    The center of our Galaxy is a known strong source of electron-positron 511-keV annihilation radiation. Thus far, however, there have been no reliable detections of annihilation radiation outside of the central radian of our Galaxy. One of the primary objectives of the INTEGRAL (INTErnational Gamma-RAy Astrophysics Laboratory) mission, launched in Oct. 2002, is the detailed study of this radiation. The Spectrometer on INTEGRAL (SPI) is a high resolution coded-aperture gamma-ray telescope with an unprecedented combination of sensitivity, angular resolution and energy resolution. We report results from the first 10 months of observation. During this period a significant fraction of the observing time was spent in or near the Galactic Plane. No positive annihilation flux was detected outside of the central region (|l| > 40 deg) of our Galaxy. In this paper we describe the observations and data analysis methods and give limits on the 511-keV flux.

  8. Electron-Positron Pair Production in an Elliptic Polarized Time Varying Field

    Institute of Scientific and Technical Information of China (English)

    XIE Bai-Song; Mohamedsedik Melike; Dulat Sayipjamal

    2012-01-01

    By using the worldline instanton method we investigate the electron-positron pair production rate from a vacuum in the presence of a time-dependent field with general elliptic polarization. It is found that as Reid polarization changes from a linear to a circular one, the pair production rate would change to some extent. When field strength is weak while frequency is high, the pair production rate changes significantly with polarization. However, when field strength is strong while frequency is low, the pair production rate from a vacuum is insensitive to field polarization and the results of the pair production rate are the same as those in a constant Reid. Our results are compared with previous work and the implications of our study are briefly discussed.%By using the worldline instanton method we investigate the electron-positron pair production rate from a vacuum in the presence of a time-dependent field with general elliptic polarization.It is found that as field polarization changes from a linear to a circular one,the pair production rate would change to some extent.When field strength is weak while frequency is high,the pair production rate changes significantly with polarization.However,when field strength is strong while frequency is low,the pair production rate from a vacuum is insensitive to field polarization and the results of the pair production rate are the same as those in a constant field.Our results are compared with previous work and the implications of our study are briefly discussed.

  9. A single particle detector for electron-ion collision experiments in the Cryogenic Storage Ring

    Energy Technology Data Exchange (ETDEWEB)

    Spruck, Kaija; Mueller, Alfred; Schippers, Stefan [Institut fuer Atom- und Molekuelphysik, Justus-Liebig-Universitaet Giessen (Germany); Krantz, Claude; Becker, Arno; Vogel, Stephen; Wolf, Andreas [Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany); Novotny, Oldrich [Columbia Astrophysics Laboratory, New York (United States)

    2014-07-01

    The study of ion chemistry in the interstellar medium requires, among others, knowledge about cross sections for the recombination of atomic and molecular ions with low temperature (∝10 K) electrons. Especially the database on singly charged atomic ions relevant to the chemistry of molecular clouds is incomplete in this respect. The electrostatic Cryogenic Storage Ring (CSR), currently being commissioned at the Max-Planck-Institute for Nuclear Physics in Heidelberg, will allow experiments with atomic, molecular and cluster ions at beam energies up to 300 keV per unit charge in a cryogenic extremely high vacuum (XHV) environment. Collisions of stored atomic ions with electrons provided by an electron cooler will lead to reaction products with charge states that differ from those of the parent particles. The detection of these products will be carried out behind a bending deflector of the storage ring by a high-efficiency movable single-particle detector, based on a secondary electron converter backed by heatable microchannel plates. The designs of the mechanical actuator and the detector are compatible with the cryogenic operating conditions at 10 K and a bakeout temperature of up to 530 K.

  10. CESAR, 2 MeV electron storage ring; general view from above.

    CERN Multimedia

    Service Photo

    1967-01-01

    CESAR (CERN Electron Storage and Accumulation Ring) was built as a study-model for the ISR (Intersecting Storage Rings). The model had to be small (24 m circumference) and yet the particles had to be highly relativistic, which led to the choice of electrons. On the other hand, in order to model the behaviour of protons, effects from synchrotron radiation had to be negligible, which meant low magnetic fields (130 G in the bending magnets) and a corresponding low energy of 1.75 MeV. All the stacking (accumulation) procedures envisaged for the ISR were proven with CESAR, and critical aspects of transverse stability were explored. Very importantly, CESAR was the test-bed for the ultrahigh vacuum techniques and components, essential for the ISR, with a final pressure of 6E-11 Torr. The CESAR project was decided early in 1960, design was completed in 1961 and construction in 1963. After an experimental period from 1964 to 1967, CESAR was dismantled in 1968.

  11. Deposition of robust multilayer mirror coatings for storage ring FEL lasing at 176nm

    Science.gov (United States)

    Günster, St.; Ristau, D.; Trovó, M.; Danailov, M.; Gatto, A.; Kaiser, N.; Sarto, F.; Piegari, A.

    2005-09-01

    Progress was achieved in the last years in the development of multilayer mirrors used in storage ring Free Electron Lasers (FEL) operating in the vacuum ultraviolet spectral range. Based on dense oxide coatings deposited by Ion Beam Sputtering, a stable lasing at 190 nm was demonstrated. The extension towards shorter wavelengths had to overcome severe problems connected to the radiation resistance and the necessary reflectivity of the resonator mirrors. In this context, radiation resistance can be considered as the ability of the mirror materials to withstand the high power laser radiation and the intense energetic background radiation generated in the synchrotron source. The bombardment with high energetic photons leads to irreversible changes and a coloration on the specimen. Reflectivity requirements can be evaluated from the tolerable losses of FEL systems. At ELETTRA FEL the resonator mirror reflectivity must be above 95 %. Evaporated fluoride multilayer mirrors provide sufficient reflectivity, but they do not exhibit an adequate radiation resistance. Pure oxide multilayers show a sufficient radiation resistance, but they cannot reach the necessary reflectivity below 190 nm. A successful approach combines evaporated fluoride multilayer stack with a dense protection layer of silicon dioxide deposited by Ion Beam Sputtering. Such mirror systems were produced reaching a reflectivity of approximately 99 % at 180 nm. Lasing in the storage ring FEL at ELETTRA was realised in the range between 176 - 179 nm. The mirror reflectivity shows only a slight degradation after lasing, which could be fully restored after the lasing experiment.

  12. Characteristics Of The Duke/ok-4 Storage Ring Fel And Gamma-ray Source

    CERN Document Server

    Park, S H

    2000-01-01

    The Duke/OK-4 storage ring is a device for driving a short wavelength Free Electron Laser (FEL). In addition, Compton scattering of the laser light from the circulating electron beam products a semi-monochromatic γ-ray source. The dynamics of such a system including accelerator physics, FEL physics, and Compton backscattering is complex and requires special study, This dissertation is a detailed theoretical and experimental analysis of such a system. The main emphasis of the theory presented here is the self-consistent analysis of the system which incorporates three drastically different processes—the dynamics of an intense electron beam, the free electron laser, and the Compton backscattering. The interdependence of these three processes and the physics of this complex system is discussed in this work. The OK-4/Duke storage ring FEL is the only accelerator facility capable of routine lasing in the deep-UV range and able to generate intense γ-ray beams with energy tunable from 2 ...

  13. Quasiperiodic spin-orbit motion and spin tunes in storage rings

    CERN Document Server

    Barber, D P; Heinemann, K

    2004-01-01

    We present an in-depth analysis of the concept of spin precession frequency for integrable orbital motion in storage rings. Spin motion on the periodic closed orbit of a storage ring can be analyzed in terms of the Floquet theorem for equations of motion with periodic parameters and a spin precession frequency emerges in a Floquet exponent as an additional frequency of the system. To define a spin precession frequency on nonperiodic synchro-betatron orbits we exploit the important concept of quasiperiodicity. This allows a generalization of the Floquet theorem so that a spin precession frequency can be defined in this case too. This frequency appears in a Floquet-like exponent as an additional frequency in the system in analogy with the case of motion on the closed orbit. These circumstances lead naturally to the definition of the uniform precession rate and a definition of spin tune. A spin tune is a uniform precession rate obtained when certain conditions are fulfilled. Having defined spin tune we define sp...

  14. Study of magnetic hysteresis effects in a storage ring using precision tune measurement

    Science.gov (United States)

    Li, Wei; Hao, Hao; Mikhailov, Stepan F.; Xu, Wei; Li, Jing-Yi; Li, Wei-Min; Wu, Ying. K.

    2016-12-01

    With the advances in accelerator science and technology in recent decades, the accelerator community has focused on the development of next-generation light sources, for example diffraction-limited storage rings (DLSRs), which require precision control of the electron beam energy and betatron tunes. This work is aimed at understanding magnet hysteresis effects on the electron beam energy and lattice focusing in circular accelerators, and developing new methods to gain better control of these effects. In this paper, we will report our recent experimental study of the magnetic hysteresis effects and their impacts on the Duke storage ring lattice using the transverse feedback based precision tune measurement system. The major magnet hysteresis effects associated with magnet normalization and lattice ramping are carefully studied to determine an effective procedure for lattice preparation while maintaining a high degree of reproducibility of lattice focusing. The local hysteresis effects are also studied by measuring the betatron tune shifts which result from adjusting the setting of a quadrupole. A new technique has been developed to precisely recover the focusing strength of the quadrupole by returning it to a proper setting to overcome the local hysteresis effect. Supported by National Natural Science Foundation of China (11175180, 11475167) and US DOE (DE-FG02-97ER41033)

  15. Vertical displacement of the storage ring floor due to building distortion in the Photon Factory

    Science.gov (United States)

    Katsura, Tomotaro; Fujita, Yutaka

    1991-11-01

    The Light Source Building of the Photon Factory was found to distort so much as to induce the displacement of magnets in the storage ring. This resulted in drifting of the beam orbit. It was considered that the building was distorted by the variations of thermal stress, such as diurnal changes of the solar irradiation and atmospheric temperature. To reduce such thermal stress, the rooftop of the building was insulated with a layer of polyethylene foam. The building distortion was measured in terms of vertical floor displacements along the storage ring by using a hydrostatic level measuring system. Results of the measurement were compared with those of a model simulation based on the finite element method. Comparison between measured and simulated results showed good agreement before the insulation applied to the roof. After the insulation, the measured floor displacements reduced to about one half and were also comparable to the simulated results. A full description of the subject is given in T. Katsura, Ed., KEK Internal 90-32 (in Japanese) Jan. (1991).

  16. Use of the Halbach perturbation theory for the multipole design of the ALS storage ring sextupole

    Energy Technology Data Exchange (ETDEWEB)

    Marks, S. [Lawrence Berkeley Lab., CA (United States)

    1995-02-01

    The Advanced Light Source (ALS) storage ring sextupole is a unique multi-purpose magnet. It is designed to operate in the primary or sextupole mode and in three auxiliary trim modes: horizontal steering, vertical steering, and skew quadrupole. Klaus Halbach developed a perturbation theory for iron-dominated magnets which provides the basis for this design. Many magnet designers, certainly those who have been exposed to Klaus, are familiar with this theory and have used it for such things as evaluating the effect of assembly alignment errors. The ALS sextupole design process was somewhat novel in its use of the perturbation theory to design essential features of the magnet. In particular, the steering and skew quadrupole functions are produced by violating sextupole symmetry and are thus perturbations of the normal sextupole excitation. The magnet was designed such that all four modes are decoupled and can be excited independently. This paper discusses the use of Halbach`s perturbation theory to design the trim functions and to evaluate the primary asymmetry in the sextupole mode, namely, a gap in the return yoke to accommodate the vacuum chamber. Prototype testing verified all operating modes of the magnet and confirmed the expected performance from calculations based upon the Halbach perturbation theory. A total of 48 sextupole magnets of this design are now installed and operating successfully in the ALS storage ring.

  17. Coherent modes for multiple non-rigid bunches in a storage ring

    Energy Technology Data Exchange (ETDEWEB)

    Berg, J.S.

    1996-03-01

    A method is presented for determining the stability of a system consisting of several highly relativistic bunches of charged particles circulating in a storage ring. The particles interact with magnets designed to guide the beam as well as with electromagnetic fields induced by the particles themselves. Previous work has considered modes where all bunches in the ring are executing the same type of internal oscillation. This dissertation considers the results of allowing those modes to couple to one another. The formalism begins with a self-consistent distribution, and analyzes small perturbations to that distribution to determine if they grow exponentially. The formalism allows one to do this computation for an arbitrary magnetic lattice, as well as an arbitrary distribution of wakefield sources around the ring. The method also allows for the inclusion of a feedback system which is designed to damp multibunch oscillations. The PEP-II B-factory with a linear lattice is used as an example to demonstrate and explain the phenomenology that results from this coupling of multibunch modes. The effect of adding feedback is also explored.

  18. Design, Modeling and Control of Magnetic Bearings for a Ring-Type Flywheel Energy Storage System

    Directory of Open Access Journals (Sweden)

    Chow-Shing Toh

    2016-12-01

    Full Text Available This study is concerned with the magnetic force models of magnetic bearing in a flywheel energy storage system (FESS. The magnetic bearing is of hybrid type, with axial passive magnetic bearing (PMB and radial hybrid magnetic bearing (HMB. For the PMB, a pair of ring-type Halbach arrays of permanent magnets are arranged vertically to support the rotor weight. For the HMB, a set of ring-type Halbach array is placed on the rotor side, which corresponds to coil sets on the stator side. The HMB can produce both attraction and repulsion forces on the radial direction, depending on the direction of the coil currents. It is found that the ring-type configuration and the differential winding scheme for coil sets can yield linear magnetic force models for both PMB and HMB. Based on the obtained magnetic force model, an integral sliding mode controller is designed for the stable rotor levitation in the radial direction. The experimental results show that the rotor can be stabilized to the bearing center, verifying the accuracy of the magnetic force models and effectiveness of the levitation controller.

  19. Evidence for a significant mixture of electron/positron pairs in FRII jets constrained by cocoon dynamics

    CERN Document Server

    Kawakatu, Nozomu; Takahara, Fumio

    2016-01-01

    We examine the plasma composition of relativistic jets in four FRII radio galaxies by analyzing the total cocoon pressure in terms of partial pressures of thermal and non-thermal electrons/positrons and protons. The total cocoon pressure is determined by cocoon dynamics via comparison of theoretical model with the observed cocoon shape. By inserting the observed number density of non-thermal electrons/positrons and the upper limit of thermal electron/positron number density into the equation of state, the number density of protons is constrained. We apply this method to four FRII radio galaxies (Cygnus A, 3C 219, 3C 223 and 3C 284), for which the total cocoon pressures have been already evaluated. We find that the positron-free plasma comprising of protons and electrons is ruled out, when we consider plausible particle distribution functions. In other words, the mixture of positrons is required for all four FRII radio galaxies; the number density ratio of electrons/positrons to protons is larger than two. Thu...

  20. Lattice Design for PEP-X Ultimate Storage Ring Light Source

    Energy Technology Data Exchange (ETDEWEB)

    Bane, K.L.F.; Cai, Y.; Nosochkov, Y.; Wang, M.-H.; /SLAC; Hettel, R.O.; /SLAC

    2011-12-13

    SLAC expertise in designing and operating high current storage rings and the availability of the 2.2-km PEP-II tunnel present an opportunity for building a next generation light source - PEP-X - that would replace the SPEAR3 storage ring in the future. The PEP-X 'baseline' design, with 164 pm-rad emittance at 4.5 GeV beam energy and a current of 1.5 A, was completed in 2010. As a next step, a so-called 'ultimate' PEP-X lattice, reducing the emittance to 11 pm-rad at zero current, has been designed. This emittance approaches the diffraction limited photon emittance for multi-keV photons, providing near maximum photon brightness and high coherence. It is achieved by using 7-bend achromat cells in the ring arcs and a 90-m damping wiggler in one of the 6 long straight sections. Details of the lattice design, dynamic aperture, and calculations of the intra-beam scattering effect and Touschek lifetime at a nominal 0.2 A current are presented. Accelerator-based light sources are in high demand for many experimental applications. The availability of the 2.2-km PEP-II tunnel at SLAC presents an opportunity for building a next generation light source - PEP-X - that would replace the existing SPEAR3 light source in the future. The PEP-X study started in 2008, and the 'baseline' design, yielding 164 pm-rad emittance at 4.5 GeV beam energy and a current of 1.5 A, was completed in 2010. This relatively conservative design can be built using existing technology. However, for a long term future, it is natural to investigate a more aggressive, so-called 'ultimate' ring design. The goal is to reduce the electron emittance in both x and y planes to near the diffraction limited photon emittance of 8 pm-rad at hard X-ray photon wavelength of 0.1 nm. This would provide a near maximum photon brightness and significant increase in photon coherence. This study was motivated by the advances in low emittance design at MAX-IV. The latter was used as a

  1. Proceedings of the 1979 workshop on beam current limitations in storage rings, July 16-27, 1979

    Energy Technology Data Exchange (ETDEWEB)

    Pellegrini, C. (ed.)

    1979-01-01

    The Workshop on Beam Current Limitations in Storage Rings was held at Brookhaven National Laboratory from July 16 to 27, 1979. The purpose of this Workshop was to discuss the physical mechanisms limiting the beam current or current density in accelerators or storage rings. Many of these machines are now being built or planned for a variety of applications, such as colliding beam experiments, synchrotron light production, heavy ion beams. This diversity was reflected in the Workshop and in the papers which have been contributed to these Proceedings. The twenty-one papers from the workshop were incorporated individually in the data base. (GHT)

  2. Simultaneous linear optics and coupling correction for storage rings with turn-by-turn beam position monitor data

    CERN Document Server

    Yang, Xi

    2015-01-01

    We propose a method to simultaneously correct linear optics errors and linear coupling for storage rings using turn-by-turn (TbT) beam position monitor (BPM) data. The independent component analysis (ICA) method is used to isolate the betatron normal modes from the measured TbT BPM data. The betatron amplitudes and phase advances of the projections of the normal modes on the horizontal and vertical planes are then extracted, which, combined with dispersion measurement, are used to fit the lattice model. The fitting results are used for lattice correction. The method has been successfully demonstrated on the NSLS-II storage ring.

  3. LIGHT SOURCE: Optics for the lattice of the compact storage ring for a Compton X-ray source

    Science.gov (United States)

    Yu, Pei-Cheng; Wang, Yu; Shen, Xiao-Zhe; Huang, Wen-Hui; Yan, Li-Xin; Du, Ying-Chao; Li, Ren-Kai; Tang, Chuan-Xiang

    2009-06-01

    We present two types of optics for the lattice of a compact storage ring for a Compton X-ray source. The optics design for different operation modes of the storage ring are discussed in detail. For the pulse mode optics, an IBS-suppression scheme is applied to optimize the optics for lower IBS emittance growth rate; as for the steady mode, the method to control momentum compact factor is adopted [Gladkikh P, Phys. Rev. ST Accel. Beams 8, 050702] to obtain stability of the electron beam.

  4. Longitudinal and transverse heating of a relativistic electron bunch induced by a storage ring free electron laser

    Directory of Open Access Journals (Sweden)

    M. Labat

    2006-10-01

    Full Text Available The new trend is to operate storage ring based light sources in a “chromatic mode” with a distributed dispersive function in the straight sections for low emittance. The electron bunch heating induced by a storage ring free electron laser (FEL has been investigated for such optics, and exhibits a more complex saturation process as compared to a usual achromatic mode of operation without dispersion in the straight sections. The correlated measured FEL power is then interpreted in terms of the electron bunch heating and compared to theoretical expectations. Experiments performed at UVSOR-II are here reported. The theoretical interpretation of the new saturation phenomenon is then discussed.

  5. Application of FEL technique for constructing high-intensity, monochromatic, polarized gamma-sources at storage rings

    Energy Technology Data Exchange (ETDEWEB)

    Saldin, E.L.; Schneidmiller, E.A.; Ulyanov, Yu.N. [Automatic Systems Corporation, Samara (Russian Federation)] [and others

    1995-12-31

    A possibility to construct high-intensity tunable monochromatic{gamma}-source at high energy storage rings is discussed. It is proposed to produce {gamma}-quanta by means of Compton backscattering of laser photons on electrons circulating in the storage. The laser light wavelength is chosen in such a way that after the scattering, the electron does not leave the separatrix. So as the probability of the scattering is rather small, energy oscillations are damped prior the next scattering. As a result, the proposed source can operate in {open_quotes}parasitic{close_quote} mode not interfering with the main mode of the storage ring operation. Analysis of parameters of existent storage rings (PETRA, ESRF, Spring-8, etc) shows that the laser light wavelength should be in infrared, {lambda}{approximately} 10 - 400 {mu}m, wavelength band. Installation at storage rings of tunable free-electron lasers with the peak and average output power {approximately} 10 MW and {approximately} 1 kW, respectively, will result in the intensity of the {gamma}-source up to {approximately} 10{sup 14}s{sup -1} with tunable {gamma}-quanta energy from several MeV up to several hundreds MeV. Such a {gamma}-source will reveal unique possibilities for precision investigations in nuclear physics.

  6. Design considerations for a digital feedback system to control self-bunching in ion-storage rings

    Directory of Open Access Journals (Sweden)

    V. Ziemann

    2001-04-01

    Full Text Available We discuss the feasibility of a digital feedback system to cure self-bunching of the electron-cooled coasting ion beam in ion-storage rings such as CELSIUS [S. Holm, A. Johansson, S. Kullander, and D. Reistad, Phys. Scr. 34, 513–532 (1986]. Such a system is based on a fast digital filter that acts as a tunable artificial wake potential. It may also aid stable operation of accumulator rings for future spallation neutron sources or heavy ion rings used for inertial fusion energy production.

  7. Sub-picosecond coherent VUV source on the Elettra storage ring

    Energy Technology Data Exchange (ETDEWEB)

    Spezzani, C. [Sincrotrone Trieste, Basovizza, Trieste (Italy)], E-mail: carlo.spezzani@elettra.trieste.it; Allaria, E.; Cautero, G. [Sincrotrone Trieste, Basovizza, Trieste (Italy); Coreno, M. [CNR-IMIP (Rome branch), c/o CNR-INFM TASC National Laboratory, Trieste (Italy); Curbis, F. [Sincrotrone Trieste, Basovizza, Trieste (Italy); University of Trieste (Italy); Danailov, M.B.; Demidovich, A.; Diviacco, B.; Karantzoulis, E.; Ivanov, R.K.; Pittana, P.; Romanzin, L.; Sergo, R.; Sigalotti, P.; Tileva, S.; Trovo, M. [Sincrotrone Trieste, Basovizza, Trieste (Italy); De Ninno, G. [Sincrotrone Trieste, Basovizza, Trieste (Italy); University of Nova Gorica (Slovenia)

    2008-11-11

    Taking advantage of the storage ring free electron laser beamline at Elettra, we have implemented an experimental setup for the generation of sub-picosecond (ps) coherent optical pulses in the VUV range. The setup is based on the frequency up-conversion of a high-power external signal (provided by a Ti:Sapphire laser) and makes use of a relativistic electron bunch as resonating medium. The produced VUV pulses have peak power in MW range, variable polarization, high shot to shot stability and control of the timing parameters at the ps level. In this paper, we present the first characterization of the temporal and spectral features of the emitted light. The radiation can be exploited for new experiments in the fields of dynamical phenomena, non-linear physics, magnetism and biology.

  8. The trigger system for the external target experiment in the HIRFL cooling storage ring

    Science.gov (United States)

    Li, Min; Zhao, Lei; Liu, Jin-Xin; Lu, Yi-Ming; Liu, Shu-Bin; An, Qi

    2016-08-01

    A trigger system was designed for the external target experiment in the Cooling Storage Ring (CSR) of the Heavy Ion Research Facility in Lanzhou (HIRFL). Considering that different detectors are scattered over a large area, the trigger system is designed based on a master-slave structure and fiber-based serial data transmission technique. The trigger logic is organized in hierarchies, and flexible reconfiguration of the trigger function is achieved based on command register access or overall field-programmable gate array (FPGA) logic on-line reconfiguration controlled by remote computers. We also conducted tests to confirm the function of the trigger electronics, and the results indicate that this trigger system works well. Supported by the National Natural Science Foundation of China (11079003), the Knowledge Innovation Program of the Chinese Academy of Sciences (KJCX2-YW-N27), and the CAS Center for Excellence in Particle Physics (CCEPP).

  9. Direct observation of spatio-temporal dynamics of short electron bunches in storage rings

    CERN Document Server

    Evain, C; Parquier, M Le; Szwaj, C; Tordeux, M -A; Manceron, L; Brubach, J -B; Roy, P; Bielawski, S

    2016-01-01

    In recent synchrotron radiation facilities, the use of short (picosecond) electron bunches is a powerful method for producing giant pulses of Terahertz Coherent Synchrotron Radiation (THz CSR). Here we report on the first direct observation of these pulse shapes with a few picoseconds resolution, and of their dynamics over a long time. We thus confirm in a very direct way the theories predicting an interplay between two physical processes. Below a critical bunch charge, we observe a train of identical THz pulses (a broadband Terahertz comb) stemming from the shortness of the electron bunches. Above this threshold, a large part of the emission is dominated by drifting structures, which appear through spontaneous self-organization. These challenging single-shot THz recordings are made possible by using a recently developed photonic time stretch detector with a high sensitivity. The experiment has been realized at the SOLEIL storage ring.

  10. Observation of microwave radiation using low-cost detectors at the ANKA storage ring*

    CERN Document Server

    Judin, V; Hofmann, A; Huttel, E; Kehrer, B; Klein, M; Marsching, S; Müller, A S; Nasse, M; Smale, N; Caspers, F; Peier, P

    2011-01-01

    Synchrotron light sources emit Coherent Synchrotron Radiation (CSR) for wavelengths longer than or equal to the bunch length. At most storage rings CSR cannot be observed, because the vacuum chamber cuts off radiation with long wavelengths. There are different approaches for shifting the CSR to shorter wavelengths that can propagate through the beam pipe, e.g.: the accelerator optics can be optimized for a low momentum compaction factor, thus reducing the bunch length. Alternatively, laser slicing can modulate substructures on long bunches [1]. Both techniques extend the CSR spectrum to shorter wavelengths, so that CSR is emitted at wavelengths below the waveguide shielding cut off. Usually fast detectors, like superconducting bolometer detector systems or Schottky barrier diodes, are used for observation of dynamic processes in accelerator physics. In this paper, we present observations of microwave radiation at ANKA using an alternative detector, a LNB (Low Noise Block) system. These devices are usually use...

  11. Recent experience with inductive insert at the proton storage ring (PSR)

    Energy Technology Data Exchange (ETDEWEB)

    Ng, K.-Y (Kal Y.); Griffin, J. E. (James E.); Wildman, D.; Popovic, M. (Mihai); Browman, A. A. (Andrew A.); Fitzgerald, D. H. (Daniel H.); Macek, R. J. (Robert J.); Plum, M. A. (Michael A.); Spickermann, T. J. (Thomas J.)

    2001-01-01

    In a Fermilab-Los Alamos collaboration, inductances constructed of ferrite cores sufficient to cancel a large fraction of the space charge potential-well distortion were installed in the Los Alamos Proton Storage Ring (PSR) as one means of raising the threshold for the two-stream e-p instability. When operating at higher intensities and with sufficient inductance added for full space-charge compensation, an unacceptable longitudinal self-bunching, microwavelike, instability was encountered. Heating the cores to N 130 C proved to be an effective cure, and was found to be a means for tuning the inductance over a limited but useful range. The heated inductors were an essential ingredient in achieving a record accumulation of 9.7 pC/pulse. An engineered version of the inductors is now installed for routine operation of the PSR. A summary of the inductor characteristics, theory of operation, experimental results, and interpretation will be presented.

  12. Effects of vertical girder realignment in the Argonne APS storage ring.

    Energy Technology Data Exchange (ETDEWEB)

    Lessner, E.

    1999-04-14

    The effects of vertical girder misalignments on the vertical orbit of the Advanced Photon Source (APS) storage ring are studied. Partial sector-realignment is prioritized in terms of the closed-orbit distortions due to misalignments of the corresponding girders in the sectors. A virtual girder-displacement (VGD) method is developed that allows the effects of a girder realignment to be tested prior to physically moving the girder. The method can also be used to anticipate the corrector strengths needed to restore the beam orbit after a realignment. Simulation results are compared to experimental results and found to reproduce the latter quite closely. Predicted corrector strengths are also found to be close to the actual local corrector strengths after a proof-of-principle two-sector realignment was performed.

  13. Non-Linear Beam Dynamics Studies of the Diamond Storage Ring

    CERN Document Server

    Bartolini, Riccardo; Belgroune, Mahdia; Henry Rowland, James; Jones, James; Martin, Ian; Singh, Beni

    2005-01-01

    The non-linear beam dynamics have been investigated for the non-zero dispersion lattice of the Diamond storage ring. Effects in realistic lattice configurations such as the introduction of coupling errors, beta beating, closed orbit correction, quadrupole fringe field and in-vacuum and helical insertion devices have been studied in the presence of realistic physical aperture limitations. Frequency map analysis together with 6D tracking allows identification of the limiting resonances as well as the loss locations and calculation of the influence of non-linear longitudinal motion on the Touschek lifetime. The sensitivity of the lattice to some of these effects leads to the identification of a better working point for the machine.

  14. Optimal dipole-field profiles for emittance reduction in storage rings

    Directory of Open Access Journals (Sweden)

    Chun-xi Wang

    2011-03-01

    Full Text Available In recent years nonuniform dipoles with bending-radius variation have been studied for reducing storage ring emittance. According to a new minimum-emittance theory, the effects of an arbitrary dipole can be characterized with two parameters determined by the dipole. To have a better idea of the potentials of nonuniform dipoles, here we numerically explore the possible values of these two parameters and associated bending profiles for optimal emittance reduction. Such optimization results provide a useful reference for lattice designs involving nonuniform bending. Simple bending-radius profiles (a short segment of constant radius with linear ramps on the sides were found to be close to the optimal. Basic beam and lattice properties such as emittance, energy spread, and phase advances are presented based on the optimal dipole solutions.

  15. Interferometric measurement of the beam size in the compact storage ring

    CERN Document Server

    Yamamoto, Y; Mitsuhashi, T; Amano, D; Iwasaki, H

    2001-01-01

    The beam size in the compact superconducting storage ring AURORA at Ritsumeikan University was measured using the SR-interferometer. The radiation beam from the bending magnet was passed through the double-slit and an interferogram formed in the visible spectral region was recorded using a CCD camera. The spatial coherence of the beam was derived from the analysis of the intensity profile and its dependence on the spatial frequency has yielded the beam size of 10.5 mu m in the vertical direction. It is unexpectedly small, indicating a high accuracy in the design of magnetic field in the magnet. The beam size could be varied by applying an rf kick electric field and the dependence of the beam lifetime on the size has shown that it is primarily governed by the Tauschek effect.

  16. On-line Observation Of Electron Beam Bunches In The Large Storage Ring Of Kurchatov Srs

    CERN Document Server

    Ioudin, L I; Krylov, Y V; Rezvov, V A; Stirin, A I; Valentinov, A G; Yupinov, Y L

    2004-01-01

    A complex of instrumentation for visual quantitative estimation of electron beam bunches in the big storage ring of Kurchatov Synchrotron Radiation Centre (KSRC) is tested. The bunches pass through a cylindrical electrostatic sensor whose signal is recorded by a wide-band oscillograph. The TV camera reads the optical image of the signal from the oscillograph screen. The TV signal numbering board inputs the video image to the computer memory. The monitor displays the beam bunch structure. A special program provides on-line visualisation of bunch behaviour on the beam orbit. The images of beam structure and a series of images showing the beam behaviour in the regimes of accumulation, acceleration and in the stationary regime a full power are numbered and stored.

  17. Lattice design and optimization for the PEP-X ultra low emittance storage ring at SLAC

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Min-Huey; Nosochkov, Yuri; Bane, Karl; Cai, Yunhai; Hettel, Robert; Huang, Xiaobiao; /SLAC

    2011-08-12

    SLAC is developing a long-range plan to transfer the evolving scientific programs at SSRL from the SPEAR3 light source to a much higher performing photon source. One of the possibilities is a new PEP-X 4.5 GeV storage ring that would be housed in the 2.2 km PEP-II tunnel. The PEP-X is designed to produce photon beams having brightness near 10{sup 22} (ph/s/mm{sup 2}/mrad{sup 2}/0.1% BW) at 10 keV with 3.5 m undulator at beam current of 1.5 A. This report presents an overview of the PEP-X baseline lattice design and describes the lattice optimization procedures in order to maximize the beam dynamic aperture. The complete report of PEP-X baseline design is published in SLAC report.

  18. Beam lifetime measurement and analysis in Indus-2 electron storage ring

    Indian Academy of Sciences (India)

    Pradeep Kumar; A D Ghodke; Gurnam Singh

    2013-05-01

    In this paper, the beam lifetime measurement and its theoretical analysis are presented using measured vacuum pressure and applied radio frequency (RF) cavity voltage in Indus-2 electron storage ring at 2 GeV beam energy. Experimental studies of the effect of RF cavity voltage and bunched beam filling pattern on beam lifetime are also presented. An equation of stable beam current decay is evolved and this equation closely follows the observed beam current decay pattern. It shows that the beam is stable and the beam current decay is due to the beam–residual gas interaction (vacuum lifetime) and electron–electron interaction within a bunch (Touschek lifetime). The estimated vacuum, Touschek and total beam lifetimes from analytical formulations are also compared with the measured beam lifetime.

  19. Klystron 'efficiency loop' for the ALS storage ring RF system

    Energy Technology Data Exchange (ETDEWEB)

    Kwiatkowski, Slawomir; Julian, Jim; Baptiste, Kenneth

    2002-05-20

    The recent energy crisis in California has led us to investigate the high power RF systems at the Advanced Light Source (ALS) in order to decrease the energy consumption and power costs. We found the Storage Ring Klystron Power Amplifier system operating as designed but with significant power waste. A simple proportional-integrator (PI) analog loop, which controls the klystron collector beam current, as a function of the output RF power, has been designed and installed. The design considerations, besides efficiency improvement, were to interface to the existing system without major expense. They were to also avoid the klystron cathode power supply filter's resonance in the loop's dynamics, and prevent a conflict with the existing Cavity RF Amplitude Loop dynamics. This efficiency loop will allow us to save up to 700 MW-hours of electrical energy per year and increase the lifetime of the klystron.

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

    CERN Document Server

    Koscielniak, Shane Rupert; Lindroos, M

    2001-01-01

    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 (1969) 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 coast...

  1. An ultimate storage ring lattice with vertical emittance generated by damping wigglers

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Xiaobiao [SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States)

    2015-01-06

    We discuss the approach of generating round beams for ultimate storage rings using vertical damping wigglers (with horizontal magnetic field). The vertical damping wigglers provide damping and excite vertical emittance. This eliminates the need to generate large linear coupling that is impractical with traditional off-axis injection. We use a PEP-X compatible lattice to demonstrate the approach. This lattice uses separate quadrupole and sextupole magnets with realistic gradient strengths. Intrabeam scattering effects are calculated. As a result, the horizontal and vertical emittances are 22.3 pm and 10.3 pm, respectively, for a 200 mA, 4.5 GeV beam, with a vertical damping wiggler of a total length of 90 m, a peak field of 1.5 T and a wiggler period of 100 mm.

  2. Research and Development on the Storage Ring Vacuum System for the APS Upgrade Project

    Energy Technology Data Exchange (ETDEWEB)

    Stillwell, B.; Brajuskovic, B.; Carter, J.; Cease, H.; Lill, R.; Navrotski, G.; Noonan, J.; Suthar, K.; Walters, D.; Wiemerslage, G.; Zientek, J.; Sangroula, M.

    2016-01-01

    A number of research and development activities are underway at Argonne National Laboratory to build confidence in the designs for the storage ring vacuum system required for the Advanced Photon Source Up-grade project (APS-U) [1]. The predominant technical risks are: excessive residual gas pressures during operation; insufficient beam position monitor stability; excessive beam impedance; excessive heating by induced electrical surface currents; and insufficient operational reliability. Present efforts to mitigate these risks include: building and evaluating mockup assemblies; performing mechanical testing of chamber weld joints; developing computational tools; investigating design alternatives; and performing electrical bench measurements. Status of these activities and some of what has been learned to date will be shared.

  3. The Heidelberg High Current Injector A Versatile Injector for Storage Ring Experiments

    CERN Document Server

    Von Hahn, R; Repnow, R; Schwalm, D; Welsch, C P

    2004-01-01

    The High Current Injector (HCI) was designed and built as a dedicated injector for the Test Storage Ring in Heidelberg to deliver mainly singly charged Li- and Be-ions. After start for routine operation in 1999 the HCI delivered stable beams during the following years for about 50 % of the experiments with very high reliability. Due to the requirements from the experiment the HCI changed during that period from a machine for singly charged positive ions to an injector for a large variety of molecules as well as positively or negatively charged light ions. After successful commissioning of the custom built 18 GHz high power ECR-source at its present test location various modifications and additions were made in preparation of a possible conversion into an injector for highly charged heavy ions as a second phase. This paper gives an overview of the experience gained in the passed 5 years and presents the status of the upgrade of the HCI.

  4. Active Damping of the E-P Instability at the Los Alamos Proton Storage Ring

    Energy Technology Data Exchange (ETDEWEB)

    Macek, R.J.; /Los Alamos; Assadi, S.; /Oak Ridge; Byrd, J.M.; /LBL, Berkeley; Deibele, C.E.; Henderson, S.D.; /Oak Ridge; Lee, S.Y.; /Indiana U.; McCrady, R.C.; /Los Alamos; Pivi, M.F.T.; /SLAC; Plum, M.A.; /Oak Ridge; Walbridge, S.B.; /Indiana U.; Zaugg, T.J.; /Los Alamos

    2008-03-17

    A prototype of an analog, transverse (vertical) feedback system for active damping of the two-stream (e-p) instability has been developed and successfully tested at the Los Alamos Proton Storage Ring (PSR). This system was able to improve the instability threshold by approximately 30% (as measured by the change in RF buncher voltage at instability threshold). The feedback system configuration, setup procedures, and optimization of performance are described. Results of several experimental tests of system performance are presented including observations of instability threshold improvement and grow-damp experiments, which yield estimates of instability growth and damping rates. A major effort was undertaken to identify and study several factors limiting system performance. Evidence obtained from these tests suggests that performance of the prototype was limited by higher instability growth rates arising from beam leakage into the gap at lower RF buncher voltage and the onset of instability in the horizontal plane, which had no feedback.

  5. Coupling field maps of combined function bending magnets to linear optics for the SESAME storage ring

    CERN Document Server

    Milanese, A

    2013-01-01

    This note provides several analyses of the combined function bending magnets of the SESAME storage ring. The objective is to develop tools to couple the magnetic design to the linear optics specifications. Such tools can be used to carry out a 3D field optimization, at the design phase and following magnetic measurements, in particular in order to fine tune the end shims on the poles. The analyses take as input field maps on the midplane, which are then processed in different ways to obtain linear transfer matrices for the optics, in the horizontal and vertical planes. Some peculiarities of this kind of magnet are also highlighted, for example, the slight variation of gradient along the arc. For convenience, the relative codes and scripts are included in the appendix.

  6. The design improvement of horizontal stripline kicker in TPS storage ring

    Science.gov (United States)

    Chou, P. J.; Chan, C. K.; Chang, C. C.; Hsu, K. T.; Hu, K. H.; Kuan, C. K.; Sheng, I. C.

    2017-07-01

    We plan to replace the existing horizontal stripline kicker of the transverse feedback system with an improved design. Large reflected power was observed at the downstream port of stripline kicker driven by the feedback amplifier. A rapid surge of vacuum pressure was observed when we tested the high current operation in TPS storage ring in April 2016. A burned feedthrough of the horizontal stripline kicker was discovered during a maintenance shutdown. The improved design is targeted to reduce the reflection of driving power from feedback system and to reduce beam induced RF heating. This major modification of the design is described. The results of RF simulation performed with the electromagnetic code GdfidL are reported as well.

  7. Coherent Synchrotron Radiation and Bunch Stability in a Compact Storage Ring

    Energy Technology Data Exchange (ETDEWEB)

    Venturini, M.

    2005-01-25

    We examine the effect of the collective force due to coherent synchrotron radiation (CSR) in an electron storage ring with small bending radius. In a computation based on time-domain integration of the nonlinear Vlasov equation, we find the threshold current for a longitudinal microwave instability induced by CSR alone. The model accounts for suppression of radiation at long wavelengths due to shielding by the vacuum chamber. In a calculation just above threshold, small ripples in the charge distribution build up over a fraction of a synchrotron period, but then die out to yield a relatively smooth but altered distribution with eventual oscillations in bunch length. The instability evolves from small noise on an initial smooth bunch of rms length much greater than the shielding cutoff.

  8. Experimental demonstration and visual observation of dust trapping in an electron storage ring

    Directory of Open Access Journals (Sweden)

    Yasunori Tanimoto

    2009-11-01

    Full Text Available Sudden decreases in the beam lifetime, which are attributed to the dust trappings, sometimes occur at the electron storage ring Photon Factory Advanced Ring (PF-AR. Since these dust events cause difficulties in user operations, we have been carefully observing this phenomenon for many years. Our observations indicated that the dust trappings could be caused by electric discharges in vacuum ducts. In order to demonstrate this hypothesis experimentally, we designed a new vacuum device that intentionally generates electric discharges and installed it in PF-AR. Using this device, we could repeatedly induce sudden decreases in the beam lifetime because of the generated electric discharge. We also detected decreases in the beam lifetime caused by mechanical movement of the electrodes in the device. Moreover, we could visually observe the dust trapping phenomenon; the trapped dust particle was observed by two video cameras and appeared as a luminous body that resembled a shooting star. This was the first direct observation of a luminous dust particle trapped by the electron beam.

  9. PEP-X: An Ultimate Storage Ring Based on Fourth-Order Geometric Achromats

    Energy Technology Data Exchange (ETDEWEB)

    Cai, Yunhai; Bane, Karl; Hettel, Robert; Nosochkov, Yuri; Wang, Min-Huey; /SLAC

    2012-04-06

    We have designed an 'ultimate' storage ring for the PEP-X light source that achieves the diffraction limited emittances (at 1.5 {angstrom}) of 12 pm-rad in both horizontal and vertical planes with a 4.5-GeV beam. These emittances include the contribution of intrabeam scattering at a nominal current of 200 mA in 3300 bunches. This quality beam in conjunction with a conventional 4-m undulator in a straight section can generate synchrotron radiation having a spectral brightness above 10{sup 22} [photons/s/mm{sup 2}/mrad{sup 2}/0.1% BW] at a 10 keV photon energy. The high coherence at the diffraction limit makes PEP-X competitive with 4th generation light sources based on an energy recovery linac. In addition, the beam lifetime is several hours and the dynamic aperture is large enough to allow off-axis injection. The alignment and stability tolerances, though challenging, are achievable. A ring with all these properties is only possible because of several major advances in mitigating the effects of nonlinear resonances.

  10. Electron Cloud Generation and Trapping in a Quadrupole Magnet at the Los Alamos Proton Storage Ring

    Energy Technology Data Exchange (ETDEWEB)

    Macek, Robert J.; Browman, Andrew A.; Ledford, John E.; /TechSource, Santa Fe /Los Alamos; Borden, Michael J.; O' Hara, James F.; McCrady, Rodney C.; Rybarcyk, Lawrence J.; Spickermann, Thomas; Zaugg, Thomas J.; /Los Alamos; Pivi, Mauro T.F.; /SLAC

    2008-03-17

    Recent beam physics studies on the two-stream e-p instability at the LANL proton storage ring (PSR) have focused on the role of the electron cloud generated in quadrupole magnets where primary electrons, which seed beam-induced multipacting, are expected to be largest due to grazing angle losses from the beam halo. A new diagnostic to measure electron cloud formation and trapping in a quadrupole magnet has been developed, installed, and successfully tested at PSR. Beam studies using this diagnostic show that the 'prompt' electron flux striking the wall in a quadrupole is comparable to the prompt signal in the adjacent drift space. In addition, the 'swept' electron signal, obtained using the sweeping feature of the diagnostic after the beam was extracted from the ring, was larger than expected and decayed slowly with an exponential time constant of 50 to 100 {micro}s. Other measurements include the cumulative energy spectra of prompt electrons and the variation of both prompt and swept electron signals with beam intensity. Experimental results were also obtained which suggest that a good fraction of the electrons observed in the adjacent drift space for the typical beam conditions in the 2006 run cycle were seeded by electrons ejected from the quadrupole.

  11. Cornell College Students Achieve the Highly Improbable

    Science.gov (United States)

    Ault, Addison

    2000-11-01

    On Tuesday, March 14, 2000, at Cornell College, Mount Vernon, Iowa, two students who prepared the photochromic compound 2-(2,4-dinitrobenzyl)pyridine obtained their product as a single crystal, one weighing 864 mg and the other 891 mg. As far as we know, this has happened only once before, also at Cornell College in Iowa. The web version of this paper includes a time-lapse video of the photochromic conversion in which the original brown-sugar brown crystals turn into the blue-jeans blue form under the influence of the photographer's floodlight.

  12. Nonlinear Landau damping and modulation of electrostatic waves in a nonextensive electron-positron-pair plasma.

    Science.gov (United States)

    Chatterjee, Debjani; Misra, A P

    2015-12-01

    The nonlinear theory of amplitude modulation of electrostatic wave envelopes in a collisionless electron-positron (EP) pair plasma is studied by using a set of Vlasov-Poisson equations in the context of Tsallis' q-nonextensive statistics. In particular, the previous linear theory of Langmuir oscillations in EP plasmas [Saberian and Esfandyari-Kalejahi, Phys. Rev. E 87, 053112 (2013)] is rectified and modified. Applying the multiple scale technique (MST), it is shown that the evolution of electrostatic wave envelopes is governed by a nonlinear Schrödinger (NLS) equation with a nonlocal nonlinear term ∝P∫|ϕ(ξ',τ)|(2)dξ'ϕ/(ξ-ξ') [where P denotes the Cauchy principal value, ϕ is the small-amplitude electrostatic (complex) potential, and ξ and τ are the stretched coordinates in MST], which appears due to the wave-particle resonance. It is found that a subregion 1/3Landau damping) due to the nonlocal nonlinearity in the NLS equation. Furthermore, the effect of the nonlinear Landau damping is to slow down the amplitude of the wave envelope, and the corresponding decay rate can be faster the larger is the number of superthermal particles in pair plasmas.

  13. Hidden-Sector Higgs Bosons at a High-Energy Electron-Positron Collider

    CERN Document Server

    Collins, J.H.

    2012-01-01

    The possibility of a scalar messenger that can couple the Standard Model (SM) to a hidden sector has been discussed in a variety of contexts in the literature in recent years. We consider the case that a new scalar singlet charged under an exotic spontaneously broken Abelian gauge symmetry mixes weakly with the SM Higgs resulting in two scalar mass states, one of which has heavily suppressed couplings to the SM particles. Previous phenomenological studies have focussed on potential signatures for such a model at the Large Hadron Collider (LHC). However, there are interesting regions of the parameter space in which the heavier Higgs state would be just out of reach for LHC searches if its mass is & 1 TeV. We therefore investigate the discovery potential for such a particle at a 3 TeV electron-positron collider, which is motivated by the recent R&D developments of the Compact Linear Collider (CLIC). We find that such an experiment could substantially extend our discovery reach for a heavy, weakly couple...

  14. Hidden-Sector Higgs Bosons at High-Energy Electron-Positron Colliders

    CERN Document Server

    Collins, Jack H

    2012-01-01

    The possibility of a scalar messenger that can couple the Standard Model (SM) to a hidden sector has been discussed in a variety of contexts in the literature in recent years. We consider the case that a new scalar singlet charged under an exotic spontaneously broken Abelian gauge symmetry mixes weakly with the SM Higgs resulting in two scalar mass states, one of which has heavily suppressed couplings to the SM particles. Previous phenomenological studies have focussed on potential signatures for such a model at the Large Hadron Collider (LHC). However, there are interesting regions of the parameter space in which the heavier Higgs state would be out of reach for LHC searches if its mass is greater than 1 TeV. We therefore investigate the discovery potential for such a particle at a 3 TeV electron-positron collider, which is motivated by the recent developments of the Compact Linear Collider (CLIC). We find that such an experiment could substantially extend our discovery reach for a heavy, weakly coupled Higg...

  15. Nonlinear excitations for the positron acoustic shock waves in dissipative nonextensive electron-positron-ion plasmas

    Science.gov (United States)

    Saha, Asit

    2017-03-01

    Positron acoustic shock waves (PASHWs) in unmagnetized electron-positron-ion (e-p-i) plasmas consisting of mobile cold positrons, immobile positive ions, q-nonextensive distributed electrons, and hot positrons are studied. The cold positron kinematic viscosity is considered and the reductive perturbation technique is used to derive the Burgers equation. Applying traveling wave transformation, the Burgers equation is transformed to a one dimensional dynamical system. All possible vector fields corresponding to the dynamical system are presented. We have analyzed the dynamical system with the help of potential energy, which helps to identify the stability and instability of the equilibrium points. It is found that the viscous force acting on cold mobile positron fluid is a source of dissipation and is responsible for the formation of the PASHWs. Furthermore, fully nonlinear arbitrary amplitude positron acoustic waves are also studied applying the theory of planar dynamical systems. It is also observed that the fundamental features of the small amplitude and arbitrary amplitude PASHWs are significantly affected by the effect of the physical parameters q e , q h , μ e , μ h , σ , η , and U. This work can be useful to understand the qualitative changes in the dynamics of nonlinear small amplitude and fully nonlinear arbitrary amplitude PASHWs in solar wind, ionosphere, lower part of magnetosphere, and auroral acceleration regions.

  16. Semiclassical picture for electron-positron photoproduction in strong laser fields

    Science.gov (United States)

    Meuren, Sebastian; Keitel, Christoph H.; Di Piazza, Antonino

    2016-04-01

    The nonlinear Breit-Wheeler process is studied in the presence of strong and short laser pulses. We show that for a relativistically intense plane-wave laser field many features of the momentum distribution of the produced electron-positron pair like its extension, region of highest probability and carrier-envelope phase effects can be explained from the classical evolution of the created particles in the background field. To this end an intuitive semiclassical picture based on the local constant-crossed field approximation applied on the probability-amplitude level is established and compared with the standard approach used in QED-PIC codes. The main difference is the substructure of the spectrum, which results from interference effects between macroscopically separated formation regions. In order to compare the predictions of the semiclassical approach with exact calculations, a very fast numerical scheme is introduced. It renders the calculation of the fully differential spectrum on a grid which resolves all interference fringes feasible. Finally, the difference between classical and quantum absorption of laser four-momentum in the process is pointed out and the dominance of the former is proven. As a self-consistent treatment of the quantum absorption is not feasible within existing QED-PIC approaches, our results provide reliable error estimates relevant for regimes where the laser depletion due to a developing QED cascade becomes significant.

  17. Oblique propagation of ion-acoustic solitary waves in a magnetized electron-positron-ion plasma

    Energy Technology Data Exchange (ETDEWEB)

    Ferdousi, M.; Sultana, S.; Mamun, A. A. [Department of Physics, Jahangirnagar University, Savar, Dhaka-1342 (Bangladesh)

    2015-03-15

    The properties of obliquely propagating ion-acoustic solitary waves in the presence of ambient magnetic field have been investigated theoretically in an electron-positron-ion nonthermal plasma. The plasma nonthermality is introduced via the q-nonextensive distribution of electrons and positrons. The Korteweg-de Vries (K-dV) and modified K-dV (mK-dV) equations are derived by adopting reductive perturbation method. The solution of K-dV and modified K-dV equation, which describes the solitary wave characteristics in the long wavelength limit, is obtained by steady state approach. It is seen that the electron and positron nonextensivity and external magnetic field (obliqueness) have significant effects on the characteristics of solitary waves. A critical value of nonextensivity is found for which solitary structures transit from positive to negative potential. The findings of this investigation may be used in understanding the wave propagation in laboratory and space plasmas where static external magnetic field is present.

  18. PIC simulations of the MagnetoRotational instability in electron-positron plasmas

    Science.gov (United States)

    Inchingolo, Giannandrea; Grismayer, Thomas; Loureiro, Nuno F.; Fonseca, Ricardo A.; Silva, Luis O.

    2016-10-01

    The magnetorotational instability (MRI) is a crucial mechanism of angular momentum transport in a variety of astrophysical scenarios, as e-e+ plasmas accretion disks nearness neutron stars and black holes. The MRI has been widely studied using MHD models and simulations, in order to understand the behavior of astrophysical fluids in a state of differential rotation. When the timescale for electron and ion collisions is longer than the inflow time in the disk, the plasma is macroscopically collisionless and MHD breaks down. This is the case of the limit of weak magnetic field, i.e., as the ratio of the ion cyclotron frequency to orbital frequency becomes small. Leveraging on the recent addition of the shearing co-rotating frames equations of motion and Maxwell's equations modules in our PIC code OSIRIS 3.0, we intend to present our recent results of the analysis of MRI in electron-positron plasma in the limit of weak magnetic field. We will recall the theoretical 1D linear model of Krolik et Zweibel that describes the behavior of MRI in the limit of weak magnetic field and use it to support our results. Moving to 2D simulations, the analysis of MRI via PIC code permits to investigate also how MRI will act in comparison with other Kinetic instabilities, like mirror instability.

  19. Parametric decays in relativistic magnetized electron-positron plasmas with relativistic temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Lopez, Rodrigo A.; Munoz, Victor [Departamento de Fisica, Facultad de Ciencias, Universidad de Chile, Casilla 653, Santiago (Chile); Asenjo, Felipe A. [Institute for Fusion Studies, University of Texas at Austin, Austin, Texas 78712 (United States); Alejandro Valdivia, J. [Departamento de Fisica, Facultad de Ciencias, Universidad de Chile, Casilla 653, Santiago (Chile); Centro para el Desarrollo de la Nanociencia y la Nanotecnologia, CEDENNA, Santiago (Chile)

    2012-08-15

    The nonlinear evolution of a circularly polarized electromagnetic wave in an electron-positron plasma propagating along a constant background magnetic field is considered, by studying its parametric decays. Relativistic effects, of the particle motion in the wave field and of the plasma temperature, are included to obtain the dispersion relation of the decays. The exact dispersion relation of the pump wave has been previously calculated within the context of a relativistic fluid theory and presents two branches: an electromagnetic and an Alfven one. We investigate the parametric decays for the pump wave in these two branches, including the anomalous dispersion zone of the Alfven branch where the group velocity is negative. We solve the nonlinear dispersion relation for different pump wave amplitudes and plasma temperatures, finding various resonant and nonresonant wave couplings. We are able to identify these couplings and study their behavior as we modify the plasma parameters. Some of these couplings are suppressed for larger amplitudes or temperatures. We also find two kinds of modulational instabilities, one involving two sideband daughter waves and another involving a forward-propagating electroacoustic mode and a sideband daughter wave.

  20. Electron-Positron Outflows from $\\gamma$-Ray Emitting Accretion Discs

    CERN Document Server

    Beloborodov, A M

    1999-01-01

    An electron-positron atmosphere is inevitably created around a black hole accretion disc whose spectrum extends to MeV energies. Pairs created in photon-photon collisions outside the disc are blown away by soft radiation (which dominates the bolometric luminosity of the disc) and form a semi-relativistic outflow. We simulate numerically the conversion of the MeV radiation into a vertical e+- outflow above a disc-like source. The outflowing e+- plasma becomes optically thick to Thomson scattering if the compactness of the gamma-ray source exceeds 30. The scattering by e+- then collimates the bulk of soft radiation along the disc axis, and the apparent bolometric luminosity of the disc depends strongly on its inclination to the line of sight. The anisotropic central emission may account for the lack of Fe K-alpha lines in the X-ray spectra of bright radio-quiet quasars. The scattering in e+- outflows may also explain the orientation of optical polarization in non-blazar active galactic nuclei.

  1. Nonlinear Landau damping and modulation of electrostatic waves in a nonextensive electron-positron pair plasma

    CERN Document Server

    Chatterjee, D

    2015-01-01

    The nonlinear theory of amplitude modulation of electrostatic wave envelopes in a collisionless electron-positron (EP) pair plasma is studied by using a set of Vlasov-Poisson equations in the context of Tsallis' $q$-nonextensive statistics. In particular, the previous linear theory of Langmuir oscillations in EP plasmas [Phys. Rev. E {\\bf87}, 053112 (2013)] is rectified and modified. Applying the multiple scale technique (MST), it is shown that the evolution of electrostatic wave envelopes is governed by a nonlinear Schr{\\"o}dinger (NLS) equation with a nonlocal nonlinear term $\\propto {\\cal{P}}\\int|\\phi(\\xi',\\tau)|^2d\\xi'\\phi/(\\xi-\\xi') $ [where ${\\cal P}$ denotes the Cauchy principal value, $\\phi$ is the small-amplitude electrostatic (complex) potential, and $\\xi$ and $\\tau$ are the stretched coordinates in MST] which appears due to the wave-particle resonance. It is found that a subregion $1/3

  2. Magnetorotational instability of weakly ionized and magnetized electron-positron-ion plasma

    Science.gov (United States)

    Mehdian, H.; Hajisharifi, K.; Azadnia, F.; Tajik-Nezhad, S.

    2016-10-01

    The magnetorotational instability in a differential rotating weakly ionized and magnetized plasma consisting of electron, positron, ion, and neutral particles has been investigated by using the multi-fluid model. Satisfying the current neutrality and homogeneity of the system in the equilibrium state by assuming the same unperturbed angular velocity for charge species and neutrals, the general local dispersion relation (DR) has been derived by taking into account the collision effects. By analytical examination of the obtained DR in the arbitrary and high frequency regimes, the instability conditions have been found in which the presence of light positive species (positrons) plays an important role in the instability criteria. Moreover, numerical investigation shows the broadening of instability range as well as increasing the maximum growth rate of instability (especially for the small number density ratio of light to heavy positive species) in the presence of positrons. The obtained results of the present investigation will greatly contribute to the understanding of the particles' dynamics as well as dissipation mechanism in some astrophysical environments, such as the region of accretion disks surrounding the central of black holes and protoplanetary disks.

  3. Modulation of a compressional electromagnetic wave in a magnetized electron-positron quantum plasma.

    Science.gov (United States)

    Amin, M R

    2015-09-01

    Amplitude modulation of a compressional electromagnetic wave in a strongly magnetized electron-positron pair plasma is considered in the quantum magnetohydrodynamic regime. The important ingredients of this study are the inclusion of the external strong magnetic field, Fermi quantum degeneracy pressure, particle exchange potential, quantum diffraction effects via the Bohm potential, and dissipative effect due to collision of the charged carriers. A modified-nonlinear Schödinger equation is developed for the compressional magnetic field of the electromagnetic wave by employing the standard reductive perturbation technique. The linear and nonlinear dispersions of the electromagnetic wave are discussed in detail. For some parameter ranges, relevant to dense astrophysical objects such as the outer layers of white dwarfs, neutron stars, and magnetars, etc., it is found that the compressional electromagnetic wave is modulationally unstable and propagates as a dissipated electromagnetic wave. It is also found that the quantum effects due to the particle exchange potential and the Bohm potential are negligibly small in comparison to the effects of the Fermi quantum degeneracy pressure. The numerical results on the growth rate of the modulation instability is also presented.

  4. Ion-acoustic rogue waves and breathers in relativistically degenerate electron-positron plasmas

    Science.gov (United States)

    Abdikian, A.; Ismaeel, S.

    2017-08-01

    In this paper, we employ a weakly relativistic fluid model to study the nonlinear amplitude modulation of electrostatic waves in an unmagnetized electron-positron-ion plasma. It is assumed that the degeneracy pressure law for electrons and positrons follows the Chandrasekhar limit of state whereas ions are warm and classical. The hydrodynamic approach along with the perturbation method have been applied to obtain the corresponding nonlinear Schrödinger equation (NLSE) in which nonlinearity is in balance with the dispersive terms. Using the NLSE, we could evaluate the modulational instability to show that various types of localized ion acoustic excitations exist in the form of either bright-type envelope solitons or dark-type envelope solitons. The regions of the stable and unstable envelope wave have been confined punctually for various regimes. Furthermore, it is proposed that the exact solutions of the NLSE for breather waves are the rogue waves (RWs), Akhmediev breather (AB), and Kuznetsov-Ma breather (KM) soliton. In order to show that the characteristics of breather structures is influenced by the plasma parameters (namely, relativistic parameter, positron concentration, and ionic temperature), the relevant numerical analysis of the NLSE is examined. In particular, it is observed that by increasing the values of the mentioned plasma parameters, the amplitude of the RWs will be decreased. Our results help researchers to explain the formation and dynamics of nonlinear electrostatic excitations in super dense astrophysical regimes.

  5. Measurement of small-angle antiproton-proton and proton-proton elastic scattering at the CERN intersecting storage rings

    NARCIS (Netherlands)

    Amos, N.; Block, M.M.; Bobbink, G.J.; Botje, M.A.J.; Favart, D.; Leroy, C.; Linde, F.; Lipnik, P.; Matheys, J-P.; Miller, D.

    1985-01-01

    Antiproton-proton and proton-proton small-angle elastic scattering was measured for centre-of-mass energies at the CERN Intersectung Storage Rings. In addition, proton-proton elastic scattering was measured at . Using the optical theorem, total cross sections are obtained with an accuracy of about

  6. A strategy for a thorough beam stability and aperture analysis for a storage ring from design considerations

    Energy Technology Data Exchange (ETDEWEB)

    Chattopadhyay, S.

    1988-07-01

    An outline of a possible approach to understanding and analyzing beam stability and related aperture as thoroughly as one can using tracking and all the other available analytic tools to date is presented in the context of designing any particular storage ring. 8 refs., 3 figs.

  7. 1000-TeV in the Center-Of-Mass: Introduction to High-Energy Storage Rings

    Energy Technology Data Exchange (ETDEWEB)

    Bjorken, J D

    1982-09-01

    The lecture discusses, in a pedagogic way, a hypothetical 500 TeV proton storage ring accelerator. It gives machine parameters, discusses linear optics and betatron motions, surveys questions of errors, tolerances and nonlinear resonances, and discusses some of the demands on the detection apparatus, especially the apparent inevitability of multiple interactions per bunch crossing. (GHT)

  8. 1000-TeV in the Center-Of-Mass: Introduction to High-Energy Storage Rings

    Energy Technology Data Exchange (ETDEWEB)

    Bjorken, J D

    1982-09-01

    The lecture discusses, in a pedagogic way, a hypothetical 500 TeV proton storage ring accelerator. It gives machine parameters, discusses linear optics and betatron motions, surveys questions of errors, tolerances and nonlinear resonances, and discusses some of the demands on the detection apparatus, especially the apparent inevitability of multiple interactions per bunch crossing. (GHT)

  9. First measurement of the Ru-96(p,gamma)Rh-97 cross section for the p process with a storage ring

    NARCIS (Netherlands)

    Mei, Bo; Aumann, Thomas; Bishop, Shawn; Blaum, Klaus; Boretzky, Konstanze; Bosch, Fritz; Brandau, Carsten; Braeuning, Harald; Davinson, Thomas; Dillmann, Iris; Dimopoulou, Christina; Ershova, Olga; Fueloep, Zsolt; Geissel, Hans; Glorius, Jan; Gyuerky, Gyoergy; Heil, Michael; Kaeppeler, Franz; Kelic-Heil, Aleksandra; Kozhuharov, Christophor; Langer, Christoph; Le Bleis, Tudi; Litvinov, Yuri; Lotay, Gavin; Marganiec, Justyna; Muenzenberg, Gottfried; Nolden, Fritz; Petridis, Nikolaos; Plag, Ralf; Popp, Ulrich; Rastrepina, Ganna; Reifarth, Rene; Riese, Bjoern; Rigollet, Catherine; Scheidenberger, Christoph; Simon, Haik; Sonnabend, Kerstin; Steck, Markus; Stoehlker, Thomas; Szuecs, Tamas; Suemmerer, Klaus; Weber, Guenter; Weick, Helmut; Winters, Danyal; Winters, Natalya; Woods, Philip; Zhong, Qiping

    2015-01-01

    This work presents a direct measurement of the Ru-96(p,gamma)Rh-97 cross section via a novel technique using a storage ring, which opens opportunities for reaction measurements on unstable nuclei. A proof-of-principle experiment was performed at the storage ring ESR at GSI in Darmstadt, where circul

  10. Progress report on the Cornell Cold Neutron Beam Facility

    Energy Technology Data Exchange (ETDEWEB)

    Clark, D.D.; Atwood, A.G.; Spern, S.A.

    1994-12-31

    The design of the Cornell Cold Neutron Source facility at the Cornell TRIGA reactor is described. The unique features are that a mesitylene moderator and copper conductors will be used which will provide simplicity and safety.

  11. Charmed and strange baryon production in 29 GeV electron positron annihilation

    Energy Technology Data Exchange (ETDEWEB)

    Klein, S.R.

    1988-06-01

    This dissertation presents measurements of the production rates of baryons with different strangeness and spin. The analyses presented here use data taken with the Mark III detector at the PEP storage ring, operating at a center of mass energy of 29 GeV. The ..xi../sup /minus// production rate is measured to be 0.017 +- 0.004 +- 0.004 per hadronic event, ..cap omega../sup /minus// production is measured to be 0.014 +- 0.006 +- 0.004 per hadronic event, and ..xi..*/sup 0/ production is less than 0.006 per hadronic event at a 90% confidence level. These measurements place strong constraints on models of baryon production. In particular, the unexpectedly high rate of ..cap omega../sup /minus// production is difficult to explain in any diquark based model. Semileptonic ..lambda../sub c//sup +/ decays have also been observed. Because neither the branching ratios nor the production rate are well known, it is difficult to interpret these results. However, they do indicate that the branching ratio for ..lambda../sub c//sup +/ ..-->.. ..lambda..l..nu.. may be higher than previous experimental measurements. 85 refs., 45 figs., 12 tabs.

  12. Jet production in the CoLoRFulNNLO method: event shapes in electron-positron collisions

    CERN Document Server

    Del Duca, Vittorio

    2016-01-01

    We present the CoLoRFulNNLO method to compute higher order radiative corrections to jet cross sections in perturbative QCD. We apply our method to the computation of event shape observables in electron-positron collisions at NNLO accuracy and validate our code by comparing our predictions to previous results in the literature. We also calculate for the first time jet cone energy fraction at NNLO.

  13. Three-jet production in electron-positron collisions using the CoLoRFulNNLO method

    CERN Document Server

    Del Duca, Vittorio

    2016-01-01

    We introduce a subtraction method for jet cross sections at next-to-next-to-leading order (NNLO) accuracy in the strong coupling and use it to compute event shapes in three-jet production in electron-positron collisions. We validate our method on two event shapes, thrust and C-parameter, which are already known in the literature at NNLO accuracy and compute for the first time oblateness and the energy-energy correlation at the same accuracy.

  14. Effect of q-nonextensive parameter and saturation time on electron density steepening in electron-positron-ion plasmas

    Science.gov (United States)

    Hashemzadeh, M.

    2015-11-01

    The effect of q-nonextensive parameter and saturation time on the electron density steepening in electron-positron-ion plasmas is studied by particle in cell method. Phase space diagrams show that the size of the holes, and consequently, the number of trapped particles strongly depends on the q-parameter and saturation time. Furthermore, the mechanism of the instability and exchange of energy between electron-positron and electric field is explained by the profiles of the energy density. Moreover, it is found that the q-parameter, saturation time, and electron and positron velocities affect the nonlinear evolution of the electron density which leads to the steepening of its structure. The q-nonextensive parameter or degree of nonextensivity is the relation between temperature gradient and potential energy of the system. Therefore, the deviation of q-parameter from unity indicates the degree of inhomogeneity of temperature or deviation from equilibrium. Finally, using the kinetic theory, a generalized q-dispersion relation is presented for electron-positron-ion plasma systems. It is found that the simulation results in the linear regime are in good agreement with the growth rate results obtained by the kinetic theory.

  15. Dynamic behavior of ion acoustic waves in electron-positron-ion magnetoplasmas with superthermal electrons and positrons

    Energy Technology Data Exchange (ETDEWEB)

    Saha, Asit, E-mail: asit-saha123@rediffmail.com, E-mail: prasantachatterjee1@rediffmail.com [Department of Mathematics, Sikkim Manipal Institute of Technology, Majitar, Rangpo, East-Sikkim 737136 (India); Department of Mathematics, Siksha Bhavana, Visva Bharati University, Santiniketan-731235 (India); Pal, Nikhil; Chatterjee, Prasanta, E-mail: asit-saha123@rediffmail.com, E-mail: prasantachatterjee1@rediffmail.com [Department of Mathematics, Siksha Bhavana, Visva Bharati University, Santiniketan-731235 (India)

    2014-10-15

    The dynamic behavior of ion acoustic waves in electron-positron-ion magnetoplasmas with superthermal electrons and positrons has been investigated in the framework of perturbed and non-perturbed Kadomtsev-Petviashili (KP) equations. Applying the reductive perturbation technique, we have derived the KP equation in electron-positron-ion magnetoplasma with kappa distributed electrons and positrons. Bifurcations of ion acoustic traveling waves of the KP equation are presented. Using the bifurcation theory of planar dynamical systems, the existence of the solitary wave solutions and the periodic traveling wave solutions has been established. Two exact solutions of these waves have been derived depending on the system parameters. Then, using the Hirota's direct method, we have obtained two-soliton and three-soliton solutions of the KP equation. The effect of the spectral index κ on propagations of the two-soliton and the three-soliton has been shown. Considering an external periodic perturbation, we have presented the quasi periodic behavior of ion acoustic waves in electron-positron-ion magnetoplasmas.

  16. Microscopic study on lasing characteristics of the UVSOR storage ring free electron laser

    Energy Technology Data Exchange (ETDEWEB)

    Hama, H. [Institute for Molecular Science, Okazaki (Japan)]|[Graduate Univ. for Advanced Stuides, Okazaki (Japan); Yamazaki, J.; Kinoshita, T. [Institute for Molecular Science, Okazaki (Japan)] [and others

    1995-12-31

    Characteristics of storage ring free electron laser (SRFEL) at a short wavelength region (UV and visible) has been studied at the UVSOR facility, Institute for Molecular Science. We have measured the laser power evolution by using a biplanar photodiode, and the micro-macro temporal structure of both the laser and the electron bunch with a dualsweep streak camera. The saturated energy of the laser micropulse in the gain-switching (Q-switching) mode has been measured as a function of the ring current. We have not observed a limitation of the output power yet within the beam current can be stored. We have analyzed the saturated micropulse energy based on a model of gain reduction due to the bunch-heating. The bunch-heating process seems to be very complicate. We derived time dependent gain variations from the shape of macropulse and the bunch length. Those two gain variations are almost consistent with each other but slightly different in detail. The gain may be not only simply reduced by the energy spread but also affected by the phase space rotation due to synchrotron oscillation of the electron bunch. As reported in previous issue, the lasing macropulse consists of a couple of micropulses that are simultaneously evolved. From high resolution two-dimensional spectra taken by the dual-sweep streak camera, we noticed considerable internal substructures of the laser micropulse in both the time distribution and the spectral shape. There are a couple of peaks separated with almost same distance in a optical bunch. Such substructure does not seem to result from statistical fluctuations of laser seeds. Although the origin of the substructure of macropulse is not dear at the present, we are going to discuss about SRFEL properties.

  17. Electron beam properties and impedance characterization for storage rings used for free electron lasers

    Energy Technology Data Exchange (ETDEWEB)

    Dattoli, G.; Mezi, L.; Renieri, A. [ENEA, Divisione Fisica Applicata, Centro Ricerche Frascati, Frascati, RM (Italy); Migliorati, M. [Rome Univ. La Sapienza, Rome (Italy). Dipt. di Energetica; Couprie, M.E.; Garzella, D.; Nutarelli, D.; Thomas, C.; De Ninno, G. [Service de Photons, Atomes et Molecules DSM/DRECAM, Gif Sur Yvette (France); Walker, R. [Sincrotrone, Basorizza, TS (Italy)

    2000-07-01

    Good electron beam qualities and stability are the crucial features of Storage Rings dedicated to synchrotron radiation sources or to Free Electron Laser. Most of these characteristics depends on the coupling of the e-beam with the machine environment, which can be in turn modelled in terms of a characteristic impedance, whose absolute value and structure can be used to specify both the stability (longitudinal and transverse) of the beam and its qualities (energy spread, bunch length, peak current ...). In this paper are considered two specific examples of Storage Rings used for FEL operation and analyze their performances by means of semi analytical and numerical methods. The analysis is aimed at clarifying the dependence of beam energy spread and bunch length on beam current and at providing a set of parameters useful for the optimization of Free Electron Laser or synchrotron radiation sources. [Italian] La qualita' di fascio di un anello di accumulazione e la sua stabilita' sono le caratteristiche cruciali di un anello di accumulazione dedicato a sorgenti di Luce di Sincrotrone o al Laser ad Elettroni Liberi. La gran parte di tali caratteristiche dipende dall'accoppiamento del fascio di elettroni con la macchina stessa, tale accoppiamento puo' essere descritto in termini di una impedenza caratteristica, il cui valore assoluto e struttura possono essere utilizzati per specificarne sia la stabilita' del fascio (longitudinale e trasversale) e le sue qualita' (dispersione di energia, lunghezza del pacchetto, corrente di picco ...). In questo articolo si considerano due esempi specifici di anelli di accumulazione utilizzati per l'operazione Laser ed Elettroni Liberi e si analizzano le loro caratteristiche per mezzo di metodi semianalitici e numerici. L'analisi e' essenzialmente dedicata a chiarire la dipendenza della dispersione di energia e della lunghezza del pacchetto dalla corrente media e a fornire un insieme di

  18. Resonant pickups for non-destructive single-particle detection in heavy-ion storage rings and first experimental results

    Energy Technology Data Exchange (ETDEWEB)

    Sanjari, Mohammad Shahab

    2013-04-26

    Nuclear astrophysics studies on highly charged radionuclides benefit from accelerator facilities with storage rings, where exotic nuclides produced with small yields can be efficiently investigated. Currently there are two accelerator facilities capable of storing highly charged heavy ions, GSI in Darmstadt and IMP in Lanzhou. Non-destructive detection methods are often used for in-flight measurements based on frequency analysis. The sensitivity of such detection systems are of primary importance specially when number of stored ions is small. Furthermore, since the exotic nuclides of interest are as a rule short-lived, the detectors must be fast. One common form of such detectors are parallel plate SCHOTTKY monitors, on which particles induce a mirror charge at each passage. This method has been successfully used at ESR experimental storage ring of GSI since 1991. In this work we describe a new resonant SCHOTTKY pickup operating as a high sensitive cavity current monitor which was mounted and commissioned in the ESR early 2010. It was successfully used in several storage ring experiments. A very similar pickup was mounted in CSRe at IMP Lanzhou in 2011. First in-ring tests have been performed and new experimental results are pending. The spectral analysis of acquired signals by the new detector has enabled a broad range of new physics experiments. The theory of operation and first experimental results and future perspectives are presented in this thesis.

  19. Insight into the electron-positron correlations in metals through the looking glass

    Science.gov (United States)

    Rubaszek, Anna

    2016-05-01

    A semi-empirical analysis of the positron annihilation experimental spectra indicates for a strong sensitivity of the two-particle electron-positron (e-p) enhancement factor to the l=s, p, d, f character of the initial electronic state [1,2]. The essential discrepancy between the models consists in the dependence of the relevant correlation functions on the energy of the annihilating electron. The present contribution contains a theoretical study of the e-p enhancement factors for s, p, d and f states as a function of the electron energy. The slope of the resulting characteristics is directly related to the degree of localisation of the s, p, d and f electrons in the electron density of states. This effect occurs especially for d electrons in transition metals, in favour to the approach of Ref. [1]. The energy dependence of the two-particle correlation functions is also a source of controversy between various theoretical approaches. The energy dependent enhancement factors describe properly the positron interaction with delocalised s and p electrons, but this approach overestimates the high momentum components of the e-p momentum densities, dominated by the localised d and f states. On the contrary, the calculations that employ the energy averaged enhancement factors match better with experiment for localised d and f electrons, but they hardly reproduce experimental spectra for nearly-free electron populations. An attempt to visit two sides of the looking glass is made in the theory of the present work. The model combines the properties of both approaches. The resulting e-p momentum densities and enhancement factors are in good agreement with the experimental data for simple, noble and transition metals, both in the low and high momentum region.

  20. The extent of non-thermal particle acceleration in relativistic, electron-positron reconnection

    Energy Technology Data Exchange (ETDEWEB)

    Werner, Greg [University of Colorado; Guo, Fan [Los Alamos National Laboratory

    2015-07-21

    Reconnection is studied as an explanation for high-energy flares from the Crab Nebula. The production of synchrotron emission >100 MeV challenges classical models of acceleration. 3D simulation shows that reconnection, converting magnetic energy to kinetic energy, can accelerate beyond γrad. The power-law index and high-energy cutoff are important for understanding the radiation spectrum dN/dγ = f(γ) ∝ γ. α and cutoff were measured vs. L and σ, where L is system (simulation) size and σ is upstream magnetization (σ = B2/4πnmc2). α can affect the high-energy cutoff. In conclusion, for collisionless relativistic reconnection in electron-positron plasma, without guide field, nb/nd=0.1: (1) relativistic magnetic reconnection yields power-law particle spectra, (2) the power law index decreases as σ increases, approaching ≈1.2. (3) the power law is cut off at an energy related to acceleration within a single current layer, which is proportional to the current layer length (for small systems, that length is the system length, yielding γc2 ≈ 0.1 L/ρ0; for large systems, the layer length is limited by secondary tearing instability, yielding γc1 ≈ 4σ; the transition from small to large is around L/ρ0 = 40σ.). (4) although the large-system energy cutoff is proportional to the average energy per particle, it is significantly higher than the average energy per particle.

  1. The trapped ion-electron instability in an electron storage ring with a gap in the bunch train

    Science.gov (United States)

    Bosch, R. A.

    2000-08-01

    The trapped ion-electron instability in an electron storage ring is studied for a broad distribution of natural ion oscillation frequencies, termed ion bounce frequencies. A gap in the train of electron bunches may be used to create bands of unstable ion bounce frequencies, so that an ion species is ejected from regions of the ring where its horizontal or vertical bounce frequency is unstable. Expressions are obtained for the reduction in the incoherent tune shifts and trapped ion-electron instability growth rates resulting from the gap.

  2. The trapped ion-electron instability in an electron storage ring with a gap in the bunch train

    Energy Technology Data Exchange (ETDEWEB)

    Bosch, R.A. E-mail: bosch@src.wisc.edu

    2000-08-11

    The trapped ion-electron instability in an electron storage ring is studied for a broad distribution of natural ion oscillation frequencies, termed ion bounce frequencies. A gap in the train of electron bunches may be used to create bands of unstable ion bounce frequencies, so that an ion species is ejected from regions of the ring where its horizontal or vertical bounce frequency is unstable. Expressions are obtained for the reduction in the incoherent tune shifts and trapped ion-electron instability growth rates resulting from the gap.

  3. Experimental study of passive compensation of space charge at the Los Alamos National Laboratory Proton Storage Ring

    Directory of Open Access Journals (Sweden)

    M. A. Plum

    1999-06-01

    Full Text Available The inductance of the vacuum chamber of the Proton Storage Ring at Los Alamos National Laboratory was intentionally increased by the introduction of ferrite rings to counteract the longitudinal space-charge effect of the intense beam. The magnetic permeability of the ferrite could be adjusted by introducing current into solenoids wound around the ferrite. Results show that the minimum rf voltage necessary to stabilize the beam against e-p instability may be reduced over that previously measured. The injected bunch length was observed to be longer when the ferrite was heavily biased so that its effect was reduced.

  4. The low-energy electron cooler for the Cryogenic Storage Ring

    Energy Technology Data Exchange (ETDEWEB)

    Vogel, Stephen; Blaum, Klaus; Krantz, Claude; Wolf, Andreas [Max-Planck-Institut fuer Kernphysik, 69117 Heidelberg (Germany)

    2014-07-01

    The Cryogenic Storage Ring (CSR) at the Max Planck Institute for Nuclear Physics in Heidelberg, Germany, is being commissioned. CSR will be an ideal tool for preparing and studying cold atomic and molecular ions using ion beams of 20-300 keV kinetic energy (per ion charge unit). As a first important upgrade CSR will be equipped with an electron cooler. Latter is designed for cooling beams with a charge-to-mass ratio q/m of 1 to 1/160 e/aμ. This corresponds to an electron beam energy range of 1 to 163 eV. The beam will be produced by a cryogenic photocathode and electron temperatures in the co-moving frame reach down to 10 K. The cooler can also be used as an electron target by detuning the electrons' kinetic energy. This allows precision experiments on low-energy collisions between cold electrons and stored atomic and molecular ions using counting and imaging detectors. The design and the status of the setup are presented.

  5. A multi-length bunch design for electron storage rings with odd buckets

    Institute of Scientific and Technical Information of China (English)

    ZHU Liang-Jing; LI Wei-Min; WANG Lin; XIANG Dao; HUANG Xiao-Biao

    2015-01-01

    A scheme with two superconducting RF cavities is designed to upgrade electron storage rings with odd buckets to multi-length bunches.In this paper,the Hefei Light Source Ⅱ (HLS Ⅱ) is given as an example for odd buckets.As it is designed for 45 buckets,which is a multiple of 3,simultaneous generation of three different lengths of bunches is proposed with the presently applied user optics.The final result,without low-α optics,is to fill HLS Ⅱ with long bunches of length 50 ps,medium bunches of 23 ps and short bunches of 6 ps.Every third bucket can be filled with short bunches,of which the current limit is up to 6.6 mA,more than 60 times the limit for low-α mode.Moreover,particle tracking simulations to examine the beam dynamics,performed by ELEGANT,and calculations of the beam instabilities are presented in this paper.

  6. XAS at the materials science X-ray beamline BL8 at the DELTA storage ring

    Energy Technology Data Exchange (ETDEWEB)

    Frahm, R; Wagner, R; Luetzenkirchen-Hecht, D [Fachbereich C - Physik, Bergische Universitaet Wuppertal, Gaussstrasse 20, 42097 Wuppertal (Germany); Herdt, A, E-mail: frahm@uni-wuppertal.d [Fachbereich Physik/DELTA, Technische Universitaet Dortmund, Maria-Goeppert-Mayer-Strasse 2, 44221 Dortmund (Germany)

    2009-11-15

    The hard X-ray beamline BL 8 at the 1.5 GeV electron storage ring DELTA is described, and experimental data of different fields of research are presented. Making use of the intense X-ray beam emitted by a superconducting wiggler, the beamline is dedicated to X-ray absorption experiments. Three different monochromator crystal pairs are permanently available for experiments in the spectral range from about 1 keV to ca. 25 keV photon energy. Results of reference materials show that high quality EXAFS data can be obtained using Si(111) and Si(311) monochromators. First measurements in the energy range between 1.2 and 5 keV have been accomplished using YB{sub 66}(400) monochromator crystals. The experimental hutch accommodates a unique 6-axis diffractometer which is well suited for all kinds of diffraction and absorption experiments, including the grazing incidence geometry. The diffractometer can carry heavy loads related to non-ambient sample environments such as e.g. ultrahigh vacuum sample stages or cryostats. Here we present typical results obtained at BL8 in different areas of materials science including investigations of dilute alloys by fluorescence mode EXAFS and the study of the structural changes associated with temperature induced spin transitions of metallo-supramolecular polyelectrolyte-amphiphile-complexes.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-07-01

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

  8. Dynamic Aperture and Tolerances for PEP-X Ultimate Storage Ring Design

    Energy Technology Data Exchange (ETDEWEB)

    Borland, M.; /Argonne; Cai, Y.; Nosochkov, Y.; Wang, M.-H.; /SLAC; Hettel, R.O.; /SLAC

    2011-12-13

    A lattice for the PEP-X ultimate storage ring light source, having 11 pm-rad natural emittance at a beam energy of 4.5 GeV at zero current, using 90 m of damping wiggler and fitting into the existing 2.2-km PEP-II tunnel, has been recently designed. Such a low emittance lattice requires very strong sextupoles for chromaticity correction, which in turn introduce strong non-linear field effects that limit the beam dynamic aperture. In order to maximize the dynamic aperture we choose the cell phases to cancel the third and fourth order geometric resonances in each 8-cell arc. Four families of chromatic sextupoles and six families of geometric (or harmonic) sextupoles are added to correct the chromatic and amplitude-dependent tunes. To find the best settings of the ten sextupole families, we use a Multi-Objective Genetic Optimizer employing elegant to optimize the beam lifetime and dynamic aperture simultaneously. Then we evaluate dynamic aperture reduction caused by magnetic field multipole errors, magnet fabrication errors and misalignments. A sufficient dynamic aperture is obtained for injection, as well as workable beam lifetime.

  9. Design and erection of the storage ring ANKA; Entwurf und Aufbau des Speicherringes ANKA

    Energy Technology Data Exchange (ETDEWEB)

    Einfeld, D. [Forschungszentrum Karlsruhe GmbH Technik und Umwelt (Germany). FGS

    2000-07-01

    The storage ring ANKA has been designed to meet the requirements of its main users: the LIGA technique and the analytical applications. According to this ANKA has to provide photons with an energy of up to 30 keV with a medium emittance (50 to 90 nm . rad), but with a high photon flux which corresponds to a stored beam of 400 mA. The nominal energy of ANKA is 2.5 GeV with a magnetic flux in the bendings of 1,5 T. To reach the emittance a classical DBA-structure over an angle of 45 degree has been used. ANKA has a circumference of 110.4 m with 4 long straight sections (5.6 m long) for the accomodation of future insertion devices and 4 short straight section (2.2 m) for the r. f. as well as the injection system. The injector is a 500 MeV booster synchrotron with a 53 MeV racetrack microtron as a pre-injector. (orig.)

  10. New energy ramping control system in the Pohang Light Source Storage Ring

    CERN Document Server

    Kim, E S; Seo, J H; Nam, S H

    2003-01-01

    A new energy ramping control system is developed to increase electron beam energy from 2.0 GeV to 2.5 GeV in the Pohang Light Source storage ring. The control system shows faster energy ramping and more stable beam characteristics than the previous energy ramping control system that consists of an operator interface workstation, subsystem control computer and machine interface units. The previous system controls current settings of the magnet power supplies in multiple steps with different energy increment rate during the energy ramping. In order to improve synchronization of the magnet power supply systems and beam stabilities during the energy ramping, we developed the energy ramping controller hardware that is controlled using a network of optical fibers. Thus, the new ramping system is able to control more synchronously the magnet power supplies with a constant energy increment rate during the energy ramping. With this reliable synchronization, it is also possible to perform the energy de-ramping step fro...

  11. HISTRAP: Proposal for a Heavy Ion Storage Ring for Atomic Physics

    Energy Technology Data Exchange (ETDEWEB)

    1988-11-01

    This paper presents an overview of the physics capabilities of HISTRAP together with a brief description of the facility and a sampling of the beams which will be available for experimentation, and surveys some of the lines of investigation in the physics of multicharged ions, molecular ion spectroscopy, condensed beams, and nuclear physics that will become possible with the advent of HISTRAP. Details of the accelerator design are discussed, including computer studies of beam tracking in the HISTRAP lattice, a discussion of the HHIRF tandem and ECR/RFQ injectors, and a description of the electron beam cooling system. In the past three years, HISTRAP has received substantial support from Oak Ridge National Laboratory management and staff. The project has used discretionary funds to develop hardware prototypes and carry out design studies. Construction has been completed on a vacuum test stand which models 1/16 of the storage ring and has attained a pressure of 4 x 10/sup -12/ Torr; a prototype rf cavity capable of accelerating beams up to 90 MeV/nucleon and decelerating to 20 keV/nucleon; and a prototype dipole magnet, one of the eight required for the HISTRAP lattice. This paper also contains a summary of the work on electron cooling carried out by one of our staff members at CERN. Building structures and services are described. Details of cost and schedule are also discussed. 77 refs.

  12. Measurement of bunch length in Indus-1 storage ring using fast photodiode

    Science.gov (United States)

    Garg, Akash Deep; Nathwani, R. K.; Holikatti, A. C.; Kumar Karnewar, Akhilesh; Tyagi, Y.; Yadav, S.; Puntambekar, T. A.; Navathe, C. P.

    2012-11-01

    The length of electron bunches in a storage ring is an important parameter for both synchrotron radiation users and accelerator physicists. Several methods are used for measurements of bunch length using electronic and optical instruments. We have measured temporal profile of synchrotron radiation emitted from dipole magnet of Indus-1 by using fast photodiode. Bunch length is calculated by assuming gaussian profile for the particles inside bunch. The results show that bunch length is increasing with the decrease of gap voltage of RF cavity. These measurements were carried out at low beam current; at high voltage results are in close agreement with theory and the values estimated using ZAP code. In the second experiment, the results show that bunch length increases with the increase of beam current inside the bunch, and above threshold current, it follows Chao-Gareyte scaling law. The longitudinal broadband impedance for Indus-1 SRS was estimated using Keil-Schnell criterion and results were compared with theoretical estimated values using ZAP code.

  13. Investigation on the fabrication of the 3rd harmonic superconducting cavity for the SSRF storage ring

    Institute of Scientific and Technical Information of China (English)

    MA Zhen-Yu; MA Guang-Ming; YU Hai-Bo; MAO Dong-Qing; FENG Zi-Qiang; HOU Hong-Tao; LIU Jian-Fei

    2009-01-01

    A third harmonic superconducting niobium cavity has been proposed for installation in the Shang-hai Synchrotron Radiation Facility (SSRF) storage ring to improve the Touschek lifetime. In order to investigate the feasibility of the superconducting cavity fabrication indigenously and the possibility to master the fabrica-tion techniques, cavities were fabricated from copper and niobium sheets by deep drawing and electron-beam welding, and a series of measurements, such as resonant frequency, shape dimensions and wall thickness, were carried out during this process. After analysis of various problems existing in the fabrication process, tech-nique improvements were proposed, and finally the precise shape as designed and resonant frequency within 1.2 MHz were achieved for the new completed cavities. In addition, full annealing was finally proved to be a good cure for niobium sheets' tearing up during deep drawing. By fabricating niobium cavities successfully, some problems to the next step were cleared. This paper introduces the process of cavity fabrication and its technique improvements towards forming, and the initial vertical test result of niobium cavity is also presented.

  14. Efficient cascaded parameter scan approach for studying top-off safety in storage rings

    Directory of Open Access Journals (Sweden)

    Yongjun Li

    2011-03-01

    Full Text Available We introduce a new algorithm, which we call the cascaded parameter scan method, to efficiently carry out the scan over magnet parameters in the safety analysis for top-off injection in synchrotron radiation storage rings. In top-off safety analysis, one must track particles populating phase space through a beam line containing magnets and apertures and clearly demonstrate that, for all possible magnet settings and errors, all particles are lost on scrapers within the properly shielded region. In the usual approach, if one considers m magnets and scans each magnet through n setpoints, then one must carry out n^{m} tracking runs. In the cascaded parameter scan method, the number of tracking runs is reduced to n×m. This reduction of exponential to linear dependence on the number of setpoints n greatly reduces the required computation time and allows one to more densely populate phase space and to increase the number n of setpoints scanned for each magnet.

  15. Beam instrumentation for the Ultra-low energy Storage Ring (USR)

    Energy Technology Data Exchange (ETDEWEB)

    Panniello, M.; Kuehnel, K. U.; Papash, A. [Max Planck Institute for Nuclear Physics (Germany); Harasimowicz, J.; Putignano, M.; Siggel-King, M. R. F.; Welsch, Carsten P., E-mail: c.p.welsch@liverpool.ac.uk [Cockcroft Institute (United Kingdom)

    2012-12-15

    The electrostatic Ultra-low energy Storage Ring (USR) at the future Facility for Low energy Antiproton and Ion Research (FLAIR) will make available antiprotons from 300 keV down to 20 keV beam energy. This multipurpose machine puts challenging demands on the beam instrumentation due to the varied bunch structure (ultra-short bunches of 1-2 ns up to a quasi-DC beam structure on the other), together with variable very low beam energies, ultra-low currents of down to 1 nA (or even less in the transfer lines which means less than 2 Multiplication-Sign 10{sup 7} particles). Thus, the development of new diagnostic devices is required as most of the standard techniques are not suitable. Within the QUASAR Group, the necessary beam instrumentation for the commissioning phase and standard operation of the USR, as well as advanced techniques such as a gas curtain-jet beam profile monitor, have been developed and prototypes of all devices have been built up. This paper presents the design of all beam diagnostics devices for the USR and summarizes the results from first measurements.

  16. The search for electric dipole moments of light ions in storage rings

    Science.gov (United States)

    Rathmann, Frank; Saleev, Artem; Nikolaev, N. N.; Jedi; srEdm Collaborations

    2013-07-01

    The Standard Model (SM) of Particle Physics is not capable of accounting for the apparent matter-antimatter asymmetry of our universe. Physics beyond the SM is required and is searched for by (i) employing highest energies (e.g., at LHC), and (ii) striving for ultimate precision and sensitivity (e.g., in the search for electric dipole moments (EDMs)). Permanent EDMs of particles violate both time reversal (T) and parity (P) invariance, and are via the CPT-theorem also CP-violating. Finding an EDM would be a strong indication for physics beyond the SM, and reducing upper limits further provides crucial tests for any corresponding theoretical model, e.g., SUSY. Direct searches for proton and deuteron EDMs bear the potential to reach sensitivities beyond 10-29 e·cm. For an all-electric proton storage ring, this goal is pursued by the US-based srEDM collaboration [1], while the newly founded Jülich-based JEDI collaboration [2] is pursuing an approach using a combined electric-magnetic lattice, which shall provide access to the EDMs of protons, deuterons, and 3He ions in the same machine. In addition, JEDI has recently proposed making a direct measurement of the proton and/or deuteron EDM at COSY using resonant techniques involving Wien filters.

  17. Search for electric dipole moments of light ions in storage rings

    Science.gov (United States)

    Rathmann, F.; Saleev, A.; Nikolaev, N. N.

    2014-01-01

    The Standard Model (SM) of Particle Physics is not capable to account for the apparent matterantimatter asymmetry of our Universe. Physics beyond the SM is required and is searched for by (i) employing highest energies (e.g., at LHC), and (ii) striving for ultimate precision and sensitivity (e.g., in the search for electric dipole moments (EDMs)). Permanent EDMs of particles violate both time reversal ( T) and parity ( P) invariance, and are via the CPT-theorem also CP-violating. Finding an EDM would be a strong indication for physics beyond the SM, and pushing upper limits further provides crucial tests for any corresponding theoretical model, e.g., SUSY. Direct searches of proton and deuteron EDMs bear the potential to reach sensitivities beyond 10-29 e cm. For an all-electric proton storage ring, this goal is pursued by the US-based srEDM collaboration [2], while the newly found Julich-based JEDI collaboration [1] is pursuing an approach using a combined electric-magnetic lattice which shall provide access to the EDMs of protons, deuterons, and 3He ions in the same machine. In addition, JEDI has recently proposed to perform a direct measurement of the proton and/or deuteron EDM at COSY using resonant techniques involving Wien filters.

  18. Towards an RF-Wien-filter for EDM experiments in storage rings

    Energy Technology Data Exchange (ETDEWEB)

    Mey, Sebastian; Gebel, Ralf [Forschungszentrum Juelich GmbH, Juelich (Germany); Collaboration: JEDI-Collaboration

    2015-07-01

    The JEDI Collaboration (Juelich Electric Dipole Moment (EDM) Investigations) is developing tools for the measurement of permanent EDMs of charged, light hadrons in storage rings. While the standard model prediction for the EDM gives unobservably small magnitudes, a non-vanishing EDM can lead to a tiny build-up of vertical polarization in a beforehand horizontally polarized beam. This requires a spin tune modulation by an RF Wien-Filter *. In the course of 2014, a prototype RF ExB-Dipole has been successfully commissioned and tested. To determine the characteristics of the device, the force of a radial magnetic field is canceled out by a vertical electric one to achieve a net Lorentz-Force compensation. In this configuration, it directly rotates the particles' polarization vector. We were able to verify that the device can be used to continuously flip the vertical polarization of a 970 MeV/c deuteron beam without exciting any coherent beam oscillations. For a first EDM Experiment, the RF ExB-Dipole in Wien-Filter mode is going to be rotated by 90 {sup circle} around the beam axis and will be used for systematic investigations of sources for false EDM signals.

  19. Spin tune investigations for the storage ring EDM experiment at COSY

    Energy Technology Data Exchange (ETDEWEB)

    Chekmenev, Stanislav [III. Physikalisches Institut, RWTH Aachen, 52056 Aachen (Germany); Collaboration: JEDI-Collaboration

    2015-07-01

    An experimental method which is aimed to find a permanent electric dipole moment (EDM) of a charged particle was proposed by JEDI (Juelich Electric Dipole moment Investigations) collaboration [1]. EDMs can be observed by their small influence on spin motion. The only possible way to perform a direct measurement is to use a storage ring. For this purpose, it was decided to carry out the first precursor experiment at the Cooler Synchrotron (COSY). Since the EDM of a particle violates CP invariance it is expected to be tiny, treatment of all various sources of systematic errors should be done with a great level of precision. A recent achievement of the JEDI collaboration is the determination of the spin tune with a precision of 10{sup -10} in a single accelerator cycle. In parallel with that achievement a new spin tracking code was developed. It is planned to use the spin tune measurement to benchmark the simulation code. In the last data taking period, spin motion changes were generated by steerers and solenoids. Comparison of simulation results with data collected will be discussed.

  20. Measurement of permanent electric dipole moments of charged hadrons in storage rings

    Science.gov (United States)

    Pretz, Jörg

    2013-03-01

    Permanent Electric Dipole Moments (EDMs) of elementary particles violate two fundamental symmetries: time reversal invariance ({T}) and parity ({P}). Assuming the {CPT} theorem this implies {CP} violation. The {CP} violation of the Standard Model is orders of magnitude too small to be observed experimentally in EDMs in the foreseeable future. It is also way too small to explain the asymmetry in abundance of matter and anti-matter in our universe. Hence, other mechanisms of {CP} violation outside the realm of the Standard Model are searched for and could result in measurable EDMs. Up to now most of the EDM measurements were done with neutral particles. With new techniques it is now possible to perform dedicated EDM experiments with charged hadrons at storage rings where polarized particles are exposed to an electric field. If an EDM exists the spin vector will experience a torque resulting in change of the original spin direction which can be determined with the help of a polarimeter. Although the principle of the measurement is simple, the smallness of the expected effect makes this a challenging experiment requiring new developments in various experimental areas. Complementary efforts to measure EDMs of proton, deuteron and light nuclei are pursued at Brookhaven National Laboratory and at Forschungszentrum Jülich with an ultimate goal to reach a sensitivity of 10 - 29 e·cm.

  1. Bunch-by-bunch beam loss monitor system in BEPCⅡ storage ring%BEPCⅡ储存环逐束团丢束监测系统及应用

    Institute of Scientific and Technical Information of China (English)

    邓庆勇; 曹建社; 岳军会; 魏源源; 麻惠洲; 杜垚垚

    2014-01-01

    A new prototype system for bunch-by-bunch beam position measurement has been designed and built to monitor and analyse the beam loss in the Beijing Electron-Positron ColliderⅡ(BEPCⅡ)storage ring.The fast ADC is used to sample the analog signals from the beam position monitor,then the digital signal is processed further using programmable gate array (FP-GA).The beam information can be obtained by means of bunch-by-bunch,such as bunch position,bunch current and bunch tune.Based on system monitoring and data analysis for long terms,as well as the dedicated machine experiments,it’s relatively clear for operators to understand some trip events,especially the beam loss caused by the high-frequency cavity trip,tune drift and multiple bunch instability.The study proves that the system is very useful for the operation of accelerator.%针对北京正负电子对撞机二期工程(BEPCⅡ)在高流强下运行经常出现的突然丢束问题,研制了基于逐束团测量的丢束监测系统。束流位置探头(BPM)的四路电极信号作为监测系统的信号源,四路高速模数转换器(ADC)和现场可编程门阵列(FPGA)进行模拟信号的数字化和数字信号的处理。通过获取丢束前每个束团的位置和流强等信息来分析引起丢束的原因。结合加速器硬件情况,长时间对丢束监测系统数据的分析,以及设计的对比实验,深入研究丢束问题。系统对高频系统故障、束流不稳定性和磁铁电源系统不稳定等原因引起的丢束现象可以做出准确的判断,进而为加速器稳定运行提供优化方向。

  2. A Compact Light Source: Design and Technical Feasibility Study of a Laser-Electron Storage Ring X-Ray Source

    Energy Technology Data Exchange (ETDEWEB)

    Loewen, R

    2004-02-02

    Thomson scattering infrared photons off energetic electrons provides a mechanism to produce hard X-rays desirable for applied sciences research. Using a small, modest energy (25MeV) electron storage ring together with a resonantly-driven optical storage cavity, a narrow spectrum of hard X-rays could be produced with the quality and monochromatic intensity approaching that of beamline sources at large synchrotron radiation laboratories. The general design of this X-ray source as well as its technical feasibility are presented. In particular, the requirements of optical pulse gain enhancement in an external cavity are described and experimentally demonstrated using a CW mode-locked laser.

  3. X-ray nanoprobes and diffraction-limited storage rings: opportunities and challenges of fluorescence tomography of biological specimens.

    Science.gov (United States)

    de Jonge, Martin D; Ryan, Christopher G; Jacobsen, Chris J

    2014-09-01

    X-ray nanoprobes require coherent illumination to achieve optic-limited resolution, and so will benefit directly from diffraction-limited storage rings. Here, the example of high-resolution X-ray fluorescence tomography is focused on as one of the most voracious demanders of coherent photons, since the detected signal is only a small fraction of the incident flux. Alternative schemes are considered for beam delivery, sample scanning and detectors. One must consider as well the steps before and after the X-ray experiment: sample preparation and examination conditions, and analysis complexity due to minimum dose requirements and self-absorption. By understanding the requirements and opportunities for nanoscale fluorescence tomography, one gains insight into the R&D challenges in optics and instrumentation needed to fully exploit the source advances that diffraction-limited storage rings offer.

  4. Mini-proceedings of the workshop on heavy ion physics and instrumentation for a 15-Tm booster and storage ring

    Energy Technology Data Exchange (ETDEWEB)

    1986-11-01

    The goal of this workshop was to probe in depth a few of the areas of possible physics made possible by the availability of an intermediate energy heavy-ion physics facility. There was a special emphasis on physics that would be possible only with a storage/cooler ring. Topics discussed were nuclei far from stability, quantum electrodynamics, giant resonances and photonuclear reactions, and high energy gamma-ray production. Individual papers in this meeting were abstracted separately.

  5. Relativistic, QED and nuclear effects in highly charged ions revealed by resonant electron-ion recombination in storage rings

    OpenAIRE

    Schippers, Stefan

    2008-01-01

    Dielectronic recombination (DR) of few-electron ions has evolved into a sensitive spectroscopic tool for highly charged ions. This is due to technological advances in electron-beam preparation and ion-beam cooling techniques at heavy-ion storage rings. Recent experiments prove unambiguously that DR collision spectroscopy has become sensitive to 2nd order QED and to nuclear effects. This review discusses the most recent developments in high-resolution spectroscopy of low-energy DR resonances, ...

  6. Relativistic, QED and nuclear effects in highly charged ions revealed by resonant electron-ion recombination in storage rings

    OpenAIRE

    Schippers, Stefan

    2008-01-01

    Dielectronic recombination (DR) of few-electron ions has evolved into a sensitive spectroscopic tool for highly charged ions. This is due to technological advances in electron-beam preparation and ion-beam cooling techniques at heavy-ion storage rings. Recent experiments prove unambiguously that DR collision spectroscopy has become sensitive to 2nd order QED and to nuclear effects. This review discusses the most recent developments in high-resolution spectroscopy of low-energy DR resonances, ...

  7. Experiments on the Synchronization of an Ultrafast Cr LiSAF Laser with the ELETTRA Storage Ring and FEL Pulses

    CERN Document Server

    Ferianis, Mario; De Ninno, G; Diviacco, Bruno; Trovò, Mauro

    2004-01-01

    The techniques for synchronizing ultrafast lasers to external radio frequency reference sources are well established and characterized in the literature. However, data lack on the minimum light-to-light jitter which can be achieved in different synchrotron operation modes when an external laser is locked to the storage ring master clock. Here we present first results for the synchronization of an ultrafast Cr:LiSAF laser with electromagnetic radiation coming from the Elettra storage ring in four bunch and multi-bunch mode. In addition, data on the synchronization of the same laser with the Elettra FEL pulses, both in free running and Q-switching regime, are reported. In our experiments, laser-to-RF locking was continuously monitored using a built-in phase detection. The laser light to storage ring light locking was characterized by simultaneous acquisition of two/three pulse trains by a streak camera. In addition, pulse jitter was determined by processing of the signal of fast photodiodes monitoring the diffe...

  8. Ion optics and beam dynamics optimization at the HESR storage ring for the SPARC experiments with highly charged heavy ions

    Energy Technology Data Exchange (ETDEWEB)

    Kovalenko, Oleksandr

    2015-06-24

    The High-Energy Storage Ring (HESR) is a part of an upcoming International Facility for Antiproton and Ion Research (FAIR) at GSI in Darmstadt. A key part of a scientific program, along with antiproton physics, will be physics with highly-charged heavy ions. Phase-space cooled beams together with fixed internal target will provide an excellent environment for storage ring experiments at the HESR for the SPARC collaboration. Until recently, however, the existing ion optical lattice for the HESR was designed only for the experiments with antiproton beams. The thesis presents a new ion optical mode developed specifically for the operation of the HESR with highly charged heavy ions. The presence of the errors, such as beam momentum spread, magnetic field impurities or magnets misalignments, leads to disruption of beam dynamics: exciting of resonant motion and loss of beam stability. Within the paper, these effects are investigated with the help of numerical codes for particle accelerator design and simulation MAD-X and MIRKO. A number of correction techniques are applied to minimize the nonlinear impact on the beam dynamics and improve the experimental conditions. The application of the analytical and numerical tools is demonstrated in the experiment with uranium U{sup 90+} beam at the existing storage ring ESR, GSI.

  9. X-ray nanoprobes and diffraction-limited storage rings: opportunities and challenges of fluorescence tomography of biological specimens

    Energy Technology Data Exchange (ETDEWEB)

    Jonge, Martin D. de, E-mail: martin.dejonge@synchrotron.org.au [Australian Synchrotron, 800 Blackburn Road, Clayton, Victoria 3168 (Australia); Ryan, Christopher G. [CSIRO Earth Science and Research Engineering, Clayton, Victoria 3168 (Australia); Jacobsen, Chris J. [Advanced Photon Source, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439 (United States); Department of Physics, Chemistry of Life Processes Institute, Northwestern University, 2170 Campus Drive, Evanston, IL 60208 (United States); Chemistry of Life Processes Institute, Northwestern University, 2170 Campus Drive, Evanston, IL 60208 (United States)

    2014-08-27

    Nanoscale X-ray scanning microscopes, or X-ray nanoprobes, will benefit greatly from diffraction-limited storage rings. Here the requirements for nanoscale fluorescence tomography are explored to gain insight into the scientific opportunities and technical challenges that such sources offer. X-ray nanoprobes require coherent illumination to achieve optic-limited resolution, and so will benefit directly from diffraction-limited storage rings. Here, the example of high-resolution X-ray fluorescence tomography is focused on as one of the most voracious demanders of coherent photons, since the detected signal is only a small fraction of the incident flux. Alternative schemes are considered for beam delivery, sample scanning and detectors. One must consider as well the steps before and after the X-ray experiment: sample preparation and examination conditions, and analysis complexity due to minimum dose requirements and self-absorption. By understanding the requirements and opportunities for nanoscale fluorescence tomography, one gains insight into the R&D challenges in optics and instrumentation needed to fully exploit the source advances that diffraction-limited storage rings offer.

  10. Simulation of crystalline beams in storage rings using molecular dynamics technique

    Science.gov (United States)

    Meshkov, I.; Katayama, T.; Sidorin, A.; Smirnov, A.; Syresin, E.; Trubnikov, G.; Tsutsui, H.

    2006-03-01

    Achieving very low temperatures in the beam rest frame can present new possibilities in accelerator physics. Increasing luminosity in the collider and in experiments with targets is a very important asset for investigating rare radioactive isotopes. The ordered state of circulating ion beams was observed at several storage rings: NAP-M [Budker, et al., in: Proceedings of the 4th All-Union Conference on Charged-Particle Accelerators [in Russian], vol. 2, Nauka, Moscow, 1975, p. 309; Budker et al., Part. Accel. 7 (1976) 197; Budker et al., At. Energ. 40 (1976) 49. E. Dementev, N. Dykansky, A. Medvedko et al., Prep. CERN/PS/AA 79-41, Geneva, 1979] (Novosibirsk), ESR [M. Steck et al., Phys. Rev. Lett. 77 (1996) 3803] and SIS [Hasse and Steck, Ordered ion beams, in: Proceeding of EPAC '2000] (Darmstadt), CRYRING [Danared et al., Observation of ordered ion beams in CRYRING, in: Proceeding of PAC '2001] (Stockholm) and PALLAS [Schramm et al., in: J.L. Duggan (Eds.), Proceedings of the Conference on Appl. of Acc. in Research and Industry AIP Conference Proceedings, p. 576 (to be published)] (Munich). In this report, the simulation of 1D crystalline beams with BETACOOL code is presented. The sudden reduction of momentum spread in the ESR experiment is described with this code. Simulation shows good agreement with experimental results and also with the intrabeam scattering (IBS) theory [Martini, Intrabeam scattering in the ACOOL-AA machines, CERN PS/84-9 AA, Geneva, 1984]. The code was used to calculate characteristics of the ordered state of ion beams for the TARN-II [Katayama, TARN II project, in: Proceedings of the IUCF workshop on nuclear physics with stored cooled beams, Spencer, IN, USA, 1984].

  11. A Study of Double-Charm and Charm-Strange Baryons inElectron-Positron Annihilations

    Energy Technology Data Exchange (ETDEWEB)

    Edwards, Adam J.; /SLAC

    2007-10-15

    In this dissertation I describe a study of double-charm and charm-strange baryons based on data collected with the BABAR Detector at the Stanford Linear Accelerator Center. In this study I search for new baryons and make precise measurements of their properties and decay modes. I seek to verify and expand upon double-charm and charm-strange baryon observations made by other experiments. The BABAR Detector is used to measure subatomic particles that are produced at the PEP-II storage rings. I analyze approximately 300 million e+e- {yields} c{bar c} events in a search for the production of double-charm baryons. I search for the double-charm baryons {Xi}{sup +}{sub cc} (containing the quarks ccd) and {Xi}{sup ++}{sub cc} (ccu) in decays to {Lambda}{sup +}{sub c}K{sup -}{pi}{sup +} and {Lambda}{sup +}{sub c}K{sup -}{pi}{sup +}{pi}{sup +}, respectively. No statistically significant signals for their production are found, and upper limits on their production are determined. Statistically significant signals for excited charm-strange baryons are observed with my analysis of approximately 500 million e+e- {yields} c{bar c} events. The charged charm-strange baryons {Xi}{sub c}(2970){sup +}, {Xi}{sub c}(3055){sup +}, {Xi}{sub c}(3123){sup +} are found in decays to {Lambda}{sup +}{sub c}K{sup -}{pi}{sup +}, the same decay mode used in the {Xi}{sup +}{sub cc} search. The neutral charm-strange baryon {Xi}{sub c}(3077){sup 0} is observed in decays to {Lambda}{sup +}{sub c}K{sub 8}{pi}{sup -}. I also search for excited charm-strange baryon decays to {Lambda}{sup +}{sub c}K{sub 8}, {Lambda}{sup +}{sub c}K{sup -}, {Lambda}{sup +}{sub c}K{sub 8}{pi}{sup -}{pi}{sup +}, and {Lambda}{sup +}{sub c}K{sup -}{pi}{sup -}{pi}{sup +}. No significant charm-strange baryon signals a f h these decay modes. For each excited charm-strange baryon state that I observe, I measure its mass, natural width (lifetime), and production rate. The properties of these excited charm-strange baryons and their

  12. Hydrodynamic and kinetic models for spin-1/2 electron-positron quantum plasmas: Annihilation interaction, helicity conservation, and wave dispersion in magnetized plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Andreev, Pavel A., E-mail: andreevpa@physics.msu.ru [Faculty of Physics, Lomonosov Moscow State University, Moscow (Russian Federation)

    2015-06-15

    We discuss the complete theory of spin-1/2 electron-positron quantum plasmas, when electrons and positrons move with velocities mach smaller than the speed of light. We derive a set of two fluid quantum hydrodynamic equations consisting of the continuity, Euler, spin (magnetic moment) evolution equations for each species. We explicitly include the Coulomb, spin-spin, Darwin and annihilation interactions. The annihilation interaction is the main topic of the paper. We consider the contribution of the annihilation interaction in the quantum hydrodynamic equations and in the spectrum of waves in magnetized electron-positron plasmas. We consider the propagation of waves parallel and perpendicular to an external magnetic field. We also consider the oblique propagation of longitudinal waves. We derive the set of quantum kinetic equations for electron-positron plasmas with the Darwin and annihilation interactions. We apply the kinetic theory to the linear wave behavior in absence of external fields. We calculate the contribution of the Darwin and annihilation interactions in the Landau damping of the Langmuir waves. We should mention that the annihilation interaction does not change number of particles in the system. It does not related to annihilation itself, but it exists as a result of interaction of an electron-positron pair via conversion of the pair into virtual photon. A pair of the non-linear Schrodinger equations for the electron-positron plasmas including the Darwin and annihilation interactions is derived. Existence of the conserving helicity in electron-positron quantum plasmas of spinning particles with the Darwin and annihilation interactions is demonstrated. We show that the annihilation interaction plays an important role in the quantum electron-positron plasmas giving the contribution of the same magnitude as the spin-spin interaction.

  13. Hydrodynamic and kinetic models for spin-1/2 electron-positron quantum plasmas: Annihilation interaction, helicity conservation, and wave dispersion in magnetized plasmas

    Science.gov (United States)

    Andreev, Pavel A.

    2015-06-01

    We discuss the complete theory of spin-1/2 electron-positron quantum plasmas, when electrons and positrons move with velocities mach smaller than the speed of light. We derive a set of two fluid quantum hydrodynamic equations consisting of the continuity, Euler, spin (magnetic moment) evolution equations for each species. We explicitly include the Coulomb, spin-spin, Darwin and annihilation interactions. The annihilation interaction is the main topic of the paper. We consider the contribution of the annihilation interaction in the quantum hydrodynamic equations and in the spectrum of waves in magnetized electron-positron plasmas. We consider the propagation of waves parallel and perpendicular to an external magnetic field. We also consider the oblique propagation of longitudinal waves. We derive the set of quantum kinetic equations for electron-positron plasmas with the Darwin and annihilation interactions. We apply the kinetic theory to the linear wave behavior in absence of external fields. We calculate the contribution of the Darwin and annihilation interactions in the Landau damping of the Langmuir waves. We should mention that the annihilation interaction does not change number of particles in the system. It does not related to annihilation itself, but it exists as a result of interaction of an electron-positron pair via conversion of the pair into virtual photon. A pair of the non-linear Schrodinger equations for the electron-positron plasmas including the Darwin and annihilation interactions is derived. Existence of the conserving helicity in electron-positron quantum plasmas of spinning particles with the Darwin and annihilation interactions is demonstrated. We show that the annihilation interaction plays an important role in the quantum electron-positron plasmas giving the contribution of the same magnitude as the spin-spin interaction.

  14. Estimations of electron-positron pair production at high-intensity laser interaction with high-Z targets

    CERN Document Server

    Gryaznykh, D A; Lykov, V A

    1998-01-01

    Electron-positron pairs' generation occuring in the interaction of $10^{18}$-$10^{20}$~W/cm$^2$ laser radiation with high-Z targets are examined. Computational results are presented for the pair production and the positron yield from the target with allowance for the contribution of pair production processes due to electrons and bremsstrahlung photons. Monte-Carlo simulations using the PRIZMA code confirm the estimates obtained. The possible positron yield from high-Z targets irradiated by picosecond lasers of power $10^2$-$10^3$~TW is estimated to be $10^9$-$10^{11}$.

  15. A scanning Auger electron spectrometer for internal surface analysis of Large Electron Positron 2 superconducting radio-frequency cavities

    Energy Technology Data Exchange (ETDEWEB)

    Benvenuti, C.; Cosso, R.; Genest, J.; Hauer, M.; Lacarrere, D.; Rijllart, A.; Saban, R. [CERN, 1211 Geneva 23 (Switzerland)

    1996-08-01

    A computer-controlled surface analysis instrument, incorporating static Auger electron spectroscopy, scanning Auger mapping, and secondary electron imaging, has been designed and built at CERN to study and characterize the inner surface of superconducting radio-frequency cavities to be installed in the Large Electron Positron collider. A detailed description of the instrument, including the analytical head, the control system, and the vacuum system is presented. Some recent results obtained from the cavities provide examples of the instrument{close_quote}s capabilities. {copyright} {ital 1996 American Institute of Physics.}

  16. Electron-positron annihilation into Dirac magnetic monopole and antimonopole: the string ambiguity and the discrete symmetries

    Energy Technology Data Exchange (ETDEWEB)

    Ignatiev, A. Y.; Joshi, G.C

    1997-12-31

    We address the problem of string arbitrariness in the quantum field theory of Dirac magnetic monopoles. Different prescriptions are shown to yield different physical results. The constraints due tot he discrete symmetries (C and P) are derived for the process of electron-positron annihilation into the monopole antimonopole pair. In the case of the annihilation through one-photon channel, the production of spin 0 monopoles is absolutely forbidden; spin 1/2 monopole and antimonopole should have the same helicities or, equivalently, the monopole-antimonopole state should be p-wave {sup 1}P{sub 1}. (authors).

  17. Electron-Positron Pair Production in a Strong Laser Field Enhanced by an Assisted High Frequency Weak Field

    Institute of Scientific and Technical Information of China (English)

    Abdukerim Nuriman; XIE Bai-Song; LI Zi-Liang; Dulat Sayipjamal

    2013-01-01

    Electron-positron pair production in a strong laser field enhanced by an assisted high frequency weak field is investigated by solving the quantum Vlasov equation.The average and residual pair number densities are obtained for sinusoid electric field and it is found that the high frequency assisted weak field will enhance pair production significantly.There exists an optimal frequency of assisted field that makes the pair production number density get a maximum one,which is a few orders of higher than that without assisted field.We also discuss the other possible assisted fields.

  18. Soliton and Shock Profiles in Electron-positron-ion Degenerate Plasmas for Both Nonrelativistic and Ultra-Relativistic Limits

    Science.gov (United States)

    Haider, Md. Masum

    2016-12-01

    An attempt has been taken to find a general equation for degenerate pressure of Chandrasekhar and constants, by using which one can study nonrelativistic as well as ultra-relativistic cases instead of two different equations and constants. Using the general equation, ion-acoustic solitary and shock waves have been studied and compared, numerically and graphically, the two cases in same situation of electron-positron-ion plasmas. Korteweg-de Vries (KdV) and KdV-Barger equations have been derived as well as their solution to study the soliton and shock profiles, respectively.

  19. Top-quark pair production at next-to-next-to-leading order QCD in electron positron collisions

    CERN Document Server

    Chen, Long; Heisler, Dennis; Bernreuther, Werner; Si, Zong-Guo

    2016-01-01

    We set up a formalism, within the antenna subtraction framework, for computing the production of a massive quark-antiquark pair in electron positron collisions at next-to-next-to-leading order in the coupling $\\alpha_s$ of quantum chromodynamics at the differential level. Our formalism applies to the calculation of any infrared-safe observable. We apply this set-up to the production of top-quark top antiquark pairs in the continuum. We compute the production cross section and several distributions. We determine, in particular, the top-quark forward-backward asymmetry at order $\\alpha_s^2$. Our result agrees with previous computations of this observable.

  20. Overlap knock-out effects in the CERN intersecting storage rings (ISR)

    CERN Document Server

    Gourber, J P; Myers, S

    1977-01-01

    Overlap knock-out arises from an overlap between frequencies present in a bunched beam and the betatron frequencies in a stack. The 'single ring' effect in the interaction of a bunched beam with a stack in the same ring. Here the coupling forces are fairly linear and are transmitted by machine elements. The 'two-ring' effect is the interaction of a bunched beam with a stack in the other ring. Here the coupling forces are nonlinear since they are produced by the beam-beam interaction. A brief outline of the general theory of these effects is given. The single ring and two-ring dipole effects have been observed and shown to cause a large increase in the transverse size of the stacked beam. (4 refs).

  1. Five-membered rings as diazo components in optical data storage devices: An ab initio investigation of the lowest singlet excitation energies

    DEFF Research Database (Denmark)

    Åstrand, P.-O.; Sommer-Larsen, P.; Hvilsted, Søren;

    2000-01-01

    been investigated as diazo components for a potential use in optical das storage materials. It is found that the diazo compounds with two heterocyclic five-membered rings have pi --> pi* excitation energies corresponding to laser wavelengths in the region 450-500 nm whereas one five-membered ring...

  2. On the rich eight branch spectrum of the oblique propagating longitudinal waves in partially spin polarized electron-positron-ion plasmas

    CERN Document Server

    Andreev, Pavel A

    2016-01-01

    We consider the separate spin evolution of electrons and positrons in electron-positron and electron-positron-ion plasmas. We consider oblique propagating longitudinal waves in this systems. We report presence of the spin-electron acoustic waves and their dispersion dependencies. In electron-positron plasmas, similarly to the electron-ion plasmas, we find one spin-electron acoustic wave (SEAW) at propagation parallel or perpendicular to the external field and two spin-electron acoustic waves at the oblique propagation. At the parallel or perpendicular propagation of the longitudinal waves in electron-positron-ion plasmas we find four branches: the Langmuir wave, the positron-acoustic wave and pair of waves having spin nature, they are the SEAW and, as we called it, spin-electron-positron acoustic wave (SEPAW). At the oblique propagation we find eight longitudinal waves: the Langmuir wave, Trivelpiece-Gould wave, pair of positron-acoustic waves, pair of SEAWs, and pair of SEPAWs. Thus, for the first time, we r...

  3. Imprints of Electron-positron Winds on the Multi-wavelength Afterglows of Gamma-ray Bursts

    CERN Document Server

    Geng, J J; Huang, Y F; Li, L; Dai, Z G

    2016-01-01

    Optical re-brightenings in the afterglows of some gamma-ray bursts (GRBs) are unexpected within the framework of the simple external shock model. While it has been suggested that the central engines of some GRBs are newly born magnetars, we aim to relate the behaviors of magnetars to the optical re-brightenings. A newly born magnetar will lose its rotational energy in the form of Poynting-flux, which may be converted into a wind of electron-positron pairs through some magnetic dissipation processes. As proposed by Dai (2004), this wind will catch up with the GRB outflow and a long-lasting reverse shock would form. By applying this scenario to GRB afterglows, we find that the reverse shock propagating back into the electron-positron wind can lead to an observable optical re-brightening and a simultaneous X-ray plateau (or X-ray shallow decay). In our study, we select four GRBs, i.e., GRB 080413B, GRB 090426, GRB 091029, and GRB 100814A, of which the optical afterglows are well observed and show clear re-bright...

  4. CsI-Silicon Particle detector for Heavy ions Orbiting in Storage rings (CsISiPHOS)

    Science.gov (United States)

    Najafi, M. A.; Dillmann, I.; Bosch, F.; Faestermann, T.; Gao, B.; Gernhäuser, R.; Kozhuharov, C.; Litvinov, S. A.; Litvinov, Yu. A.; Maier, L.; Nolden, F.; Popp, U.; Sanjari, M. S.; Spillmann, U.; Steck, M.; Stöhlker, T.; Weick, H.

    2016-11-01

    A heavy-ion detector was developed for decay studies in the Experimental Storage Ring (ESR) at the GSI Helmholtz Centre for Heavy Ion Research in Darmstadt, Germany. This detector serves as a prototype for the in-pocket particle detectors for future experiments with the Collector Ring (CR) at FAIR (Facility for Antiproton and Ion Research). The detector includes a stack of six silicon pad sensors, a double-sided silicon strip detector (DSSD), and a CsI(Tl) scintillation detector. It was used successfully in a recent experiment for the detection of the β+-decay of highly charged 142Pm60+ ions. Based on the ΔE / E technique for particle identification and an energy resolution of 0.9% for ΔE and 0.5% for E (Full Width at Half Maximum (FWHM)), the detector is well-suited to distinguish neighbouring isobars in the region of interest.

  5. Analysis of the wake field effects in the PEP-II storage rings with extremely high currents

    Energy Technology Data Exchange (ETDEWEB)

    Novokhatski, A., E-mail: novo@slac.stanford.edu; Seeman, J.; Sullivan, M.

    2014-01-21

    We present the history and analysis of different wake field effects throughout the operational life of the PEP-II SLAC B-factory. Although the impedance of the high and low energy rings is small, the intense high-current beams generated a lot of power. The effects from these wake fields are: heating and damage of vacuum beam chamber elements like RF seals, vacuum valves, shielded bellows, BPM buttons and ceramic tiles; vacuum spikes, vacuum instabilities and high detector background; and beam longitudinal and transverse instabilities. We also discuss the methods used to eliminate these effects. Results of this analysis and the PEP-II experience may be very useful in the design of new storage rings and light sources.

  6. Analysis of the wake field effects in the PEP-II storage rings with extremely high currents

    Science.gov (United States)

    Novokhatski, A.; Seeman, J.; Sullivan, M.

    2014-01-01

    We present the history and analysis of different wake field effects throughout the operational life of the PEP-II SLAC B-factory. Although the impedance of the high and low energy rings is small, the intense high-current beams generated a lot of power. The effects from these wake fields are: heating and damage of vacuum beam chamber elements like RF seals, vacuum valves, shielded bellows, BPM buttons and ceramic tiles; vacuum spikes, vacuum instabilities and high detector background; and beam longitudinal and transverse instabilities. We also discuss the methods used to eliminate these effects. Results of this analysis and the PEP-II experience may be very useful in the design of new storage rings and light sources.

  7. Hydrodynamic and kinetic models for spin-1/2 electron-positron quantum plasmas: Annihilation interaction, helicity conservation, and wave dispersion in magnetized plasmas

    CERN Document Server

    Andreev, Pavel A

    2014-01-01

    We discuss complete theory of spin-1/2 electron-positron quantum plasmas, when electrons and positrons move with velocities mach smaller than the speed of light. We derive a set of two fluid quantum hydrodynamic equations consisting of the continuity, Euler, spin (magnetic moment) evolution equations for each species. We explicitly include the Coulomb, spin-spin, Darwin and annihilation interactions. The annihilation interaction is the main topic of the paper. We consider contribution of the annihilation interaction in the quantum hydrodynamic equations and in spectrum of waves in magnetized electron-positron plasmas. We consider propagation of waves parallel and perpendicular to an external magnetic field. We also consider oblique propagation of longitudinal waves. We derive set of quantum kinetic equations for electron-positron plasmas with the Darwin and annihilation interactions. We apply the kinetic theory for the linear wave behavior in absence of external fields. We calculate contribution of the Darwin...

  8. Capture, acceleration and bunching rf systems for the MEIC booster and storage rings

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Shaoheng [Jefferson Lab, Newport News, VA; Guo, Jiquan [Jefferson Lab, Newport News, VA; Lin, Fanglei [Jefferson Lab, Newport News, VA; Morozov, Vasiliy [Jefferson Lab, Newport News, VA; Rimmer, Robert A. [Jefferson Lab, Newport News, VA; Wang, Haipeng [Jefferson Lab, Newport News, VA; Zhang, Yuhong [Jefferson Lab, Newport News, VA

    2015-09-01

    The Medium-energy Electron Ion Collider (MEIC), proposed by Jefferson Lab, consists of a series of accelerators. The electron collider ring accepts electrons from CEBAF at energies from 3 to 12 GeV. Protons and ions are delivered to a booster and captured in a long bunch before being ramped and transferred to the ion collider ring. The ion collider ring accelerates a small number of long ion bunches to colliding energy before they are re-bunched into a high frequency train of very short bunches for colliding. Two sets of low frequency RF systems are needed for the long ion bunch energy ramping in the booster and ion collider ring. Another two sets of high frequency RF cavities are needed for re-bunching in the ion collider ring and compensating synchrotron radiation energy loss in the electron collider ring. The requirements from energy ramping, ion beam bunching, electron beam energy compensation, collective effects, beam loading and feedback capability, RF power capability, etc. are presented. The preliminary designs of these RF systems are presented. Concepts for the baseline cavity and RF station configurations are described, as well as some options that may allow more flexible injection and acceleration schemes.

  9. Electron beam stability and beam peak to peak motion data for NSLS X-Ray storage ring

    Energy Technology Data Exchange (ETDEWEB)

    Singh, O.

    1993-07-01

    In the past two years, a significant reduction in electron beam motion has been achieved at the NSLS X-Ray storage ring. The implementation of global analog orbit feedbacks, based on a harmonics correction scheme, has reduced the beam motion globally. Implementation of six local analog feedback systems has reduced the beam motion even further at the corresponding beam line straight sections. This paper presents beam motion measurements, showing the improvement due to the feedback systems. Beam motion is measured using a spectrum analyzer and data is presented at various frequencies, where peaks were observed. Finally, some of the beam motion sources are discussed.

  10. Progress on the Design of the Storage Ring Vacuum System for the Advanced Photon Source Upgrade Project

    Energy Technology Data Exchange (ETDEWEB)

    Stillwell, B.; Billett, B.; Brajuskovic, B.; Carter, J.; Kirkus, E.; Lale, M.; Lerch, J.; Noonan, J.; O' Neill, M.; Rocke, B.; Suthar, K.; Walters, D.; Wiemerslage, G.; Zientek, J.

    2017-06-20

    Recent work on the design of the storage ring vacuum system for the Advanced Photon Source Upgrade project (APS-U) includes: revising the vacuum system design to accommodate a new lattice with reverse bend magnets, modifying the designs of vacuum chambers in the FODO sections for more intense incident synchrotron radiation power, modifying the design of rf-shielding bellows liners for better performance and reliability, modifying photon absorber designs to make better use of available space, and integrated planning of components needed in the injection, extraction and rf cavity straight sections. An overview of progress in these areas is presented.

  11. The Pulsed Power Converter and Septum Magnet System for Injection into the Electron Storage Ring at ESRF

    CERN Document Server

    Perrine, J P; Völker, F V

    1996-01-01

    At ESRF, the European Synchrotron Radiation Facility in Grenoble, electrons are accelerated, via a 200 MeV Linac and a 6 GeV synchrotron booster, and injected into the storage ring at 10 Hz rate. Two thin septum blade magnets and an eddy current sheet type septum magnet provide the final deflection of the injected beam. The operational requirements of the e- injection scheme and the resulting demanding hardware specifications are recalled. The pulsed septum magnets are briefly described. The design, circuit layout and construction of the power converters are related with emphasis on innovative aspects of general interest. Results of tests during commissioning are reported.

  12. Three-dimensional ordering of cold ion beams in a storage ring: A molecular-dynamics simulation study

    Energy Technology Data Exchange (ETDEWEB)

    Yuri, Yosuke, E-mail: yuri.yosuke@jaea.go.jp [Takasaki Advanced Radiation Research Institute, Japan Atomic Energy Agency, 1233 Watanuki-machi Takasaki, Gunma 370-1292 Japan (Japan)

    2015-06-29

    Three-dimensional (3D) ordering of a charged-particle beams circulating in a storage ring is systematically studied with a molecular-dynamics simulation code. An ion beam can exhibit a 3D ordered configuration at ultralow temperature as a result of powerful 3D laser cooling. Various unique characteristics of the ordered beams, different from those of crystalline beams, are revealed in detail, such as the single-particle motion in the transverse and longitudinal directions, and the dependence of the tune depression and the Coulomb coupling constant on the operating points.

  13. Superconducting wiggler magnets for beam-emittance damping rings

    CERN Document Server

    Schoerling, Daniel

    2012-01-01

    Ultra-low emittance beams with a high bunch charge are necessary for the luminosity performance of linear electron-positron colliders, such as the Compact Linear Collider (CLIC). An effective way to create ultra-low emittance beams with a high bunch charge is to use damping rings, or storage rings equipped with strong damping wiggler magnets. The remanent field of the permanent magnet materials and the ohmic losses in normal conductors limit the economically achievable pole field in accelerator magnets operated at around room temperature to below the magnetic saturation induction, which is 2.15 T for iron. In wiggler magnets, the pole field in the center of the gap is reduced further like the hyperbolic cosine of the ratio of the gap size and the period length multiplied by pi. Moreover, damping wiggler magnets require relatively large gaps because they have to accept the un-damped beam and to generate, at a small period length, a large magnetic flux density amplitude to effectively damp the beam emittance....

  14. Studies of systematic limitations in the EDM searches at storage rings

    CERN Document Server

    Saleev, Artem; Rathmann, Frank

    2015-01-01

    Searches of the electric dipole moment (EDM) at a pure magnetic ring, like COSY, encounter strong background coming from magnetic dipole moment (MDM). The most troubling issue is the MDM spin rotation in the so-called imperfection, radial and longitudinal, B-fields. To study the systematic effects of the imperfection fields at COSY we proposed the original method which makes use of the two static solenoids acting as artificial imperfections. Perturbation of the spin tune caused by the spin kicks in the solenoids probes the systematic effect of cumulative spin rotation in the imperfection fields all over the ring. The spin tune is one of the most precise quantities measured presently at COSY at $10^{-10}$ level. The method has been successfully tested in September 2014 run at COSY, unravelling strength of spin kicks in the ring's imperfection fields at the level of $10^{-3} rad$.

  15. 78 FR 10172 - Lisa Anne Cornell and G. Ware Cornell, Jr. v. Princess Cruise Lines, Ltd. (Corp), Carnival PLC...

    Science.gov (United States)

    2013-02-13

    ... Lisa Anne Cornell and G. Ware Cornell, Jr. v. Princess Cruise Lines, Ltd. (Corp), Carnival PLC, and..., Jr., hereinafter ``Complainants,'' against Princess Cruise Lines, Ltd (Corp), Carnival plc, and... common carrier for hire of passengers from ports in the United States;'' Respondent Carnival plc ``is...

  16. Report of Snowmass 2001 working group E2: Electron - positron colliders from the phi to the Z

    Energy Technology Data Exchange (ETDEWEB)

    Zhen-guo Zhao et al.

    2002-12-23

    We report on the status and plans of experiments now running or proposed for electron-positron colliders at energies between the {phi} and the Z. The e{sup +}e{sup -}B and charm factories we considered were PEP-II/BABAR, KEKB/Belle, superKEK, SuperBABAR, and CESR-c/CLEO-c. We reviewed the programs at the {phi} factory at Frascati and the proposed PEP-N facility at Stanford Linear Accelerator Center. We studied the prospects for B physics with a dedicated linear collider Z factory, associated with the TESLA high energy linear collider. In all cases, we compared the physics reach of these facilities with that of alternative experiments at hadron colliders or fixed target facilities.

  17. Effects of a CPT-even and Lorentz-violating nonminimal coupling on electron-positron scattering

    Science.gov (United States)

    Casana, R.; Ferreira, M. M., Jr.; Maluf, R. V.; dos Santos, F. E. P.

    2012-12-01

    We propose a new CPT-even and Lorentz-violating nonminimal coupling between fermions and Abelian gauge fields involving the CPT-even tensor (KF)μναβ of the standard model extension. We thus investigate its effects on the cross section of the electron-positron scattering by analyzing the process e++e-→μ++μ-. Such a study was performed for the parity-odd and parity-even nonbirefringent components of the Lorentz-violating (KF)μναβ tensor. Finally, by using experimental data available in the literature, we have imposed upper bounds as tight as 10-12(eV)-1 on the magnitude of the CPT-even and Lorentz-violating parameters while nonminimally coupled.

  18. Effects of ion mobility and positron fraction on solitary waves in weak relativistic electron-positron-ion plasma

    CERN Document Server

    Lu, Ding; Xie, Bai-Song

    2013-01-01

    Effects of ion mobility and positron fraction on solitary waves of envelop of laser field and potential of electrostatic field in weak relativistic electron-positron-ion plasma are investigated. The parameter region for the existence of solitary waves is obtained analytically, and the reasonable choice of parameters is clarified. Both cases of mobile and immobile ions are considered. It is found that the amplitudes of solitary waves in the former case are larger compared to the latter case. For small plasma density, the localized solitary wave solutions in terms of approximate perturbation analytical method are consistent well with that by exact numerical calculations. However as the plasma density increases the analytical method loses its validity more and more. The influence of the positron fraction on the amplitudes of solitary waves shows a monotonous increasing relation. Implication of our results to the particle acceleration is also discussed briefly.

  19. Effects of ion mobility and positron fraction on solitary waves in weak relativistic electron-positron-ion plasma

    Science.gov (United States)

    Lu, Ding; Li, Zi-Liang; Xie, Bai-Song

    2013-09-01

    The effects of ion mobility and positron fraction on the solitary waves of the laser field envelope and the potential of the electrostatic field in weak relativistic electron-positron-ion plasma are investigated. The parameter region for the existence of solitary waves is obtained analytically, and a reasonable choice of parameters is clarified. Both cases of mobile and immobile ions are considered. It is found that the amplitudes of solitary waves in the former case are larger compared to the latter case. For small plasma density, the localized solitary wave solutions in terms of the approximate perturbation analytical method are very consistent with those by exact numerical calculations. However, as the plasma density increases the analytical method loses its validity more and more. The influence of the positron fraction on the amplitudes of solitary waves shows a monotonous increasing relation. The implications of our results to particle acceleration are also discussed briefly.

  20. Small Steps Towards a Grand Unification and the Electron/Positron Excesses in Cosmic-Ray Experiments

    Energy Technology Data Exchange (ETDEWEB)

    Ibe, Masahiro; /SLAC

    2010-06-11

    We consider a small extension of the standard model by adding two Majorana fermions; those are adjoint representations of the SU(2){sub L} and SU(3){sub c} gauge groups of the standard model. In this extension, the gauge coupling unification at an energy scale higher than 10{sup 15} GeV is realized when the masses of the triplet and the octet fermions are smaller than 10{sup 4} GeV and 10{sup 12} GeV, respectively. We also show that an appropriate symmetry ensures a long lifetime of the neutral component of the triplet fermion whose thermal relic density naturally explains the observed dark matter density. The electron/positron excesses observed in recent cosmic-ray experiments can be also explained by the decay of the triplet fermion.