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Sample records for cern beams generating

  1. Beta Beams Implementation at CERN

    CERN Document Server

    Hansen, Christian

    2011-01-01

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

  2. CERN fires up neutrino beams

    CERN Multimedia

    2006-01-01

    "CERN has switched on a new neutrino beam, aimed through the earth to the INFN Gran Sasso Laboratories some 730km away near Rome. This is the latest additin to a global endeavour to understand this most elusive of particles and unlock the secrest it carries about the origins and evolution of our Universe." (2 pages)

  3. Superconducting beam bending magnets at CERN

    CERN Multimedia

    1977-01-01

    The photo shows Gerhard Kesseler with the cyogenic vessels for one of the 10.8 Tesla-metre beam bending magnets. The magnet itself (not visible) is sitting inside the superinsukated helium vessel (white). The next larger shell and the biggest tubular structure (with the largest part behind the person) is the insulation vacuum tank. See CERN Courier 1970 pp. 228-229 CERN Courier 1973 pp. 144-145 Yellow Report CERN 78-03, 1978

  4. CERN AWAKE Facility Readiness for First Beam

    CERN Document Server

    Bracco, Chiara; Butterworth, Andrew; Damerau, Heiko; Döbert, Steffen; Fedosseev, Valentin; Feldbaumer, Eduard; Gschwendtner, Edda; Höfle, Wolfgang; Pardons, Ans; Shaposhnikova, Elena; Vincke, Helmut

    2016-01-01

    The AWAKE project at CERN was approved in August 2013 and since then a big effort was made to be able to probe the acceleration of electrons before the "2019-2020 Long Shutdown". The next steps in this challenging schedule will be a dry run of all the beam line systems, at the end of the HW commissioning in June 2016, and the first proton beam sent to the plasma cell one month later. The current status of the project is presented together with an outlook over the foreseen works for operation with electrons in 2018.

  5. The CERN Neutrino beam to Gran Sasso (NGS)

    CERN Document Server

    Bailey, R; Ball, A E; Bonnal, P; Buhler-Broglin, Manfred; Détraz, C; Elsener, Konrad; Ereditato, A; Faugeras, Paul E; Ferrari, A; Fortuna, G; Grant, A L; Guglielmi, A M; Hilaire, A; Hübner, Kurt; Jonker, M; Kissler, Karl Heinz; López-Hernandez, L A; Maugain, J M; Migliozzi, P; Palladino, Vittorio; Pietropaolo, F; Revol, Jean Pierre Charles; Sala, P R; Sanelli, C; Stevenson, Graham Roger; Vassilopoulos, N; Vincke, H H; Weisse, E; Wilhemsson, M

    1999-01-01

    The conceptual technical design of the NGS (CERN neutrino beam to Gran Sasso) facility has been presented in the report CERN 98-02 / INFN-AE/98-05. Additional information, in particular an update on various neutrino beam options for the NGS facility, has been provided in a memorandum to the CERN-SPSC Committee (CERN-SPSC/98-35). In the present report, further improvements on the NGS design and performance, in particular new scenarios for SPS proton cycles for NGS operation and a new version of the NGS "high energy" neutrino beam for nt appearance experiments, are described. This new NGS reference beam is estimated to provide three times more nt events per year than the beam presented in the 1998 report. The radiological aspects of the NGS facility have been re-examined with the new beam design. An updated version of the construction schedule is also presented.

  6. Beam-machine Interaction at the CERN LHC

    CERN Document Server

    Boccone, V; Brugger, M; Calviani, M; Cerutti, F; Esposito, L S; Ferrari, A; Lechner, A; Mereghetti, A; Nowak, E; Shetty, N V; Skordis, E; Versaci, R; Vlachoudis, V

    2014-01-01

    The radiation field generated by a high energy and intensity accelerator is of concern in terms of element functionality threat, component damage, electronics reliability, and material activation, but also provides signatures that allow actual operating conditions to be monitored. The shower initiated by an energetic hadron involves many different physical processes, down to slow neutron interactions and fragment de-excitation, which need to be accurately described for design purposes and to interpret operation events. The experience with the transport and interaction Monte Carlo code FLUKA at the Large Hadron Collider (LHC), operating at CERN with 4 TeV proton beams (and equivalent magnetic rigidity Pb beams) and approaching nominal luminosity and energy, is presented. Design, operation and upgrade challenges are reviewed in the context of beam-machine interaction account and relevant benchmarking examples based on radiation monitor measurements are shown.

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

    CERN Document Server

    AUTHOR|(CDS)2082016; Benedikt, Michael

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

  8. CERN accelerator school: Antiprotons for colliding beam facilities

    International Nuclear Information System (INIS)

    This is a specialized course which addresses a wide spectrum of theoretical and technological problems confronting the designer of an antiproton facility for high-energy-physics research. A broad and profound basis is provided by the lecturers' substantial experience gained over many years with CERN's unique equipment. Topics include beam optics, special lattices for antiproton accumulation and storage rings, antiproton production, stochastic cooling, acceleration and storage, r.f. noise, r.f. beam manipulations, beam-beam interaction, beam stability due to ion accumulation, and diagnostics. The SPS (Super Proton Synchrotron) panti p collider, LEAR (the Low Energy Antiproton Ring at CERN), antiprotons in the ISR (Intersecting Storage Rings), the new antiproton collector (ACOL) and gas jet targets are also discussed. A table is included listing the parameters of all CERN's accelerators and storage rings. See hints under the relevant topics. (orig./HSI)

  9. 2014 CERN Accelerator Schools: Beam Loss and Accelerator Protection

    CERN Multimedia

    2014-01-01

    The US-CERN-JAPAN-RUSSIA Joint International Accelerator School is organising a course on Beam Loss and Accelerator Protection to be held in Newport Beach, California, USA from 5-14 November, 2014.    This school is intended for physicists and engineers who are or may be engaged in the design, construction, and/or operation of accelerators with high power photon or particle beams and/or accelerator sub-systems with large stored energy. Application deadlines are 15 August and 4 September. Further information on this Joint School can be found at: http://cas.web.cern.ch/cas/JAS/Newport%20Beach%202014/NPBadvert.html http://indico.cern.ch/event/287647/ http://uspas.fnal.gov/programs/JAS/JAS14.shtml

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

    CERN Multimedia

    CERN Accelerator School

    2015-01-01

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

  11. High Intensity Beam Issues in the CERN Proton Synchrotron

    CERN Document Server

    Aumon, Sandra; Rivkin, Leonid

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

  12. Transverse beam coupling impedance of the CERN Proton Synchrotron

    Science.gov (United States)

    Persichelli, S.; Migliorati, M.; Biancacci, N.; Gilardoni, S.; Metral, E.; Salvant, B.

    2016-04-01

    Beam coupling impedance is a fundamental parameter to characterize the electromagnetic interaction of a particle beam with the surrounding environment. Synchrotron machine performances are critically affected by instabilities and collective effects triggered by beam coupling impedance. In particular, transverse beam coupling impedance is expected to impact beam dynamics of the CERN Proton Synchrotron (PS), since a significant increase in beam intensity is foreseen within the framework of the LHC Injectors Upgrade (LIU) project. In this paper we describe the study of the transverse beam coupling impedance of the PS, taking into account the main sources of geometrical impedance and the contribution of indirect space charge at different energies. The total machine impedance budget, determined from beam-based dedicated machine measurement sessions, is also discussed and compared with the theoretical model.

  13. Perspectives for the VITO beam line at ISOLDE, CERN

    Directory of Open Access Journals (Sweden)

    Garcia Ruiz R. F.

    2015-01-01

    Full Text Available By using polarized ion beams in combination with the β-NMR technique, the Versatile Ion-polarized Techniques On-line (VITO experiment at ISOLDE, CERN links together expertise from different fields in an unique experimental setup. An overview of the experimental techniques and a general description of the newly designed beam line are presented. Potential uses in multidisciplinary research and perspectives for future experiments are discussed.

  14. The beam coupling impedance model of CERN Proton Synchrotron

    CERN Document Server

    Persichelli, Serena; Migliorati, Mauro; Salvant, Benoit

    The research activity described in this thesis work is dedicated to developing a longitudinal and a transverse beam coupling impedance model for the CERN Proton Synchrotron (PS), in the framework of the Large Hadron Collider (LHC) Injector Upgrade (LIU) project. The study allows a better understanding of the instability threshold of the machine, helping predicting the effects of the current increase planned for the upgrade program. Furthermore, the knowledge of the machine beam coupling impedance model allows improving the stability of beams injected into the LHC chain, in prevision for the particle collision energy increase in program for LHC physics experiments.

  15. Beam loss monitors comparison at the CERN Proton Synchrotron

    CERN Document Server

    Gilardoni, S S; Effinger, E; Gil-Flores, J; Wienands, U

    2011-01-01

    CERN is planning the renovation and upgrade of the beam loss detection system for the Proton Synchrotron (PS). Improved performance in speed–to be able to monitor beam loss on a bunch-by-bunch basis–and in longterm stability–to reduce or avoid the need for periodic calibration–are aimed for. To select the most suitable technology, different detectors were benchmarked in the machine with respect to the same beam loss. The characteristics of the different detectors, the results of the measurement campaign and their suitability as future monitors for the PS are presented.

  16. CERN PSB Beam Tests of CNAO Synchrotron's Digital LLRF

    CERN Document Server

    Angoletta, M E; De Martinis, C; Falbo, L; Findlay, A; Foglio, R; Hunt, S; Tourres, D; Vescovi, C

    2008-01-01

    The Italian National Centre for Oncological hAdrontherapy (CNAO), in its final construction phase, uses proton and carbon ion beams to treat patients affected by solid tumours. At the heart of CNAO is a 78- meter circumference synchrotron that accelerates particles to up to 400 MeV/u. The synchrotron relies on a digital LLRF system based upon Digital Signal Processors (DSPs) and Field Programmable Gate Array (FPGA). This system implements cavity servoing and beam control capabilities, such as phase and radial loops. Beam tests of the CNAO synchrotron LLRF system were carried out at CERN's Proton Synchrotron Booster (PSB) in autumn 2007, to verify the combined DSP/FPGA architecture and the beam control capabilities. For this, a prototype version of CNAO's LLRF system was adapted to the PSB requirements. This paper outlines the prototype system layout and describes the tests carried out and their results. In particular, system architecture and beam control capabilities were successfully proven by comparison wit...

  17. Production of radioactive molecular beams for CERN-ISOLDE

    CERN Document Server

    AUTHOR|(SzGeCERN)703149; Kröll, Thorsten

    SOLDE, the Isotope Separation On-Line facility, at CERN is a leading facility for the production of beams of exotic radioactive isotopes. Currently over 1000 different isotopes with half lives down to milliseconds can be extracted with beam intensities of up to 10^11 ions per second. However, due to the reactive target environment not all isotopes are extractable in sufficient amounts. In this work the extraction of short lived carbon and boron isotopes is investigated. Therefore a variety of experimental and computanional techniques have been used.

  18. Production of radioactive molecular beams for CERN-ISOLDE

    Energy Technology Data Exchange (ETDEWEB)

    Seiffert, Christoph

    2015-06-15

    ISOLDE, the Isotope Separation On-Line facility, at CERN is a leading facility for the production of beams of exotic radioactive isotopes. Currently over 1000 different isotopes with half lives down to milliseconds can be extracted with beam intensities of up to 10{sup 11} ions per second. However, due to the reactive target environment not all isotopes are extractable in sufficient amounts. In this work the extraction of short lived carbon and boron isotopes is investigated. Therefore a variety of experimental and computational techniques have been used.

  19. Production of radioactive molecular beams for CERN-ISOLDE

    International Nuclear Information System (INIS)

    ISOLDE, the Isotope Separation On-Line facility, at CERN is a leading facility for the production of beams of exotic radioactive isotopes. Currently over 1000 different isotopes with half lives down to milliseconds can be extracted with beam intensities of up to 1011 ions per second. However, due to the reactive target environment not all isotopes are extractable in sufficient amounts. In this work the extraction of short lived carbon and boron isotopes is investigated. Therefore a variety of experimental and computational techniques have been used.

  20. CERN Summer Student Programme at the H-Beam, ASACUSA

    CERN Document Server

    Huzan, Myron

    2016-01-01

    The ASACUSA (Atomic Spectroscopy And Collisions Using Slow Antiprotons) collaboration opperates experiments at the Antiproton Decelerator (AD) at CERN. One of the goals is testing of CPT symmetry breaking by investigating the Ground State Hyperfine Splitting (GS-HFS) of antihydrogen (\\={H}), and comparing to that of hydrogen (H). The experiments are undertaken at the H-Beam and H-Bar experimental areas respectively and are both based on the Rabi-Spectroscopy method, but adapted for the respective experimental requirements. Being involved with the H-Beam experiment I will focus this report on the measurements undertaken on hydrogen, of which the aim is to measure the resonance frequencies of the Sigma ($\\sigma$$_{1}$) and Pi ($\\pi$$_{1}$) transitions within zero magnetic fields, an extension of the Ph.D. project of Martin Diermaier \\cite{MDiermaier}

  1. Physics at the new CERN neutron beam line

    CERN Document Server

    Guerrero, C

    2014-01-01

    A new neutron beam line (n_TOF EAR - 2) is being built at CERN within the n_TOF facility. Compared to the existing 185 meters long time - of - flight beam line, the new one (which will operate in parallel) will feature a shorter flight of 20 meters, providing a 2 7 times more intense neutron flux extending from thermal to 300 MeV. The scientific program is now bein g discussed and the first detailed proposals will be refereed by February 2014. This contribution is devoted to present and discuss the expected performance of the facility, briefly, and the details of some of the first measureme nts foreseen for 2014 and 2015.

  2. Beam instrumentation for the HIE Isolde linac at CERN

    CERN Document Server

    Sosa, A; Fraser, MA; Kadi, Y; Voulot, D; Wenander, F; Zocca, F; Sosa, A; Welsch, CP; Larman, A; Galipienzo, J

    2012-01-01

    In the framework of the High Intensity and Energy (HIE)-ISOLDE project at CERN, a beam instrumentation R&D program is on-going for the superconducting upgrade of the REX-ISOLDE heavy-ion post-accelerator. An overview of the foreseen beam diagnostics system is presented, focusing on the challenging specifications required by the HIE-ISOLDE linac. Due to the low beam intensities, the beam instrumentation will be based on high-sensitivity intercepting devices. The project includes intensity, position and transverse profile monitors to be installed in the very narrow space available in between the superconducting cryomodules. In addition, spectroscopy and time of flight (ToF) monitors are foreseen downstream of the linac to measure the energy and time distribution of the beams and to allow for a fast phase tuning of the superconducting cavities. An emittance meter will finally provide transverse emittance measurements based on the phase space sampling technique. The design status of the differ...

  3. Beam Measurement Systems for the CERN Antiproton Decelerator (AD)

    CERN Document Server

    Angoletta, Maria Elena; Ludwig, M; Marqversen, O; Odier, P; Pedersen, F; Raich, U; Søby, L; Tranquille, G; Spickermann, T

    2001-01-01

    The new, low-energy antiproton physics facility at CERN has been successfully commissioned and has been delivering decelerated antiprotons at 100 MeV/c since July 2000. The AD consists of one ring where the 3.5 GeV/c antiprotons produced from a production target are injected, rf manipulated, stochastically cooled, decelerated (with further stages involving additional stochastic and electron cooling and rf manipulation) and extracted at 100 MeV/c. While proton test beams of sufficient intensity could be used for certain procedures in AD commissioning, this was not possible for setting-up and routine operation. Hence, special diagnostics systems had to be developed to obtain the beam and accelerator characteristics using the weak antiproton beams of a few 10E7 particles at all momenta from 3.5 GeV/c down to 100 MeV/c. These include systems for position measurement, intensity, beam size measurements using transverse aperture limiters and scintillators and Schottky-based tools. This paper gives an overall view of...

  4. Java expert GUI framework for CERN beam instrumentation systems

    International Nuclear Information System (INIS)

    The CERN Beam Instrumentation Group's software section has recently performed a study of the tools used to produce Java expert GUI (Graphical User Interface) applications. This paper will present the analysis that was made to understand the requirements for generic components and the resulting tools including a collection of Java components that have been made available for a wider audience. The new expert GUI has already given very good results. Users can easily and quickly create a Java project with a pre-defined structure that will allow them to run an application in two mouse clicks. At the same time, they are able to add whatever components they need to libraries that are now common to all. The use of Maven is not completed and has led to some integration problems for our Java software architecture. Nevertheless, the handling of the library dependencies and the archetypes are very useful

  5. A Beam Interlock System for CERN High Energy Accelerators

    CERN Document Server

    Todd, Benjamin; Schmidt, R

    2006-01-01

    The Large Hadron Collider (LHC) at CERN (The European Organisation for Nuclear Research) is one of the largest and most complicated machines envisaged to date. The LHC has been conceived and designed over the course of the last 25 years and represents the cutting edge of accelerator technology with a collision energy of 14TeV, having a stored beam energy over 100 times more powerful than the nearest competitor. Commissioning of the machine is already nderway and operation with beam is intended for Autumn 2007, with 7TeV operation expected in 2008. The LHC is set to answer some of the fundemental questions in theoretical physics, colliding particles with such high energy that the inner workings of the quantum world can be revealed. Colliding particles together at such high energy makes very high demands on machine operation and protection. The specified beam energy requires strong magnetic fields that are made in superconducting dipole magnets, these magnets are kept only around two degrees above absolute zero...

  6. Development of a beam condition monitor for use in experiments at the CERN Large Hadron Collider using synthetic diamond

    CERN Document Server

    Fernández-Hernando, L; Ilgner, C; MacPherson, A; Oh, A; Pernegger, H; Pritchard, T; Stone, R; Worm, S

    2004-01-01

    The CERN Large Hadron Collider (LHC) will collide two counter rotating proton beams, each with a store energy about 350MJ; enough to melt 550kg of copper. If there is failure in an element of the accelerator, the resulting beam losses could cause damage not only to the machine but also to the experiments. A Beam Condition Monitor (BCM) is foreseen to monitor last increments of particle flux near the interaction point and if necessary, to generate an abort signal to the LHC accelerator control, to dump the beams. Due to its radiation hardness and minimal services requirements, synthetic CVD diamond is being considered as BCM sensor option. (12 refs).

  7. Preparation of a primary argon beam for the CERN fixed target physics.

    Science.gov (United States)

    Küchler, D; O'Neil, M; Scrivens, R; Thomae, R

    2014-02-01

    The fixed target experiment NA61 in the North Area of the Super Proton Synchrotron is studying phase transitions in strongly interacting matter. Up to now they used the primary beams available from the CERN accelerator complex (protons and lead ions) or fragmented beams created from the primary lead ion beam. To explore a wider range of energies and densities a request was made to provide primary argon and xenon beams. This paper describes the results of the setting up and 10 week test run of the Ar(11+) beam from the 14.5 GHz ECR ion source and the linear accelerator (Linac3) at CERN.

  8. CERN Accelerator School - Beam injection, extraction and transfer

    CERN Multimedia

    2016-01-01

    Registration is now open for the CERN Accelerator School’s specialised course to be held in Erice, Italy, from 10 to 19 March, 2017.   The course will be of interest to staff and students in accelerator laboratories, university departments and companies manufacturing accelerator who wish to learn about accelerator science and technology. Further information can be found at: http://indico.cern.ch/event/451905/ http://cas.web.cern.ch/cas/IET2017/IET-advert.html

  9. Beam Transfer Systems for the LAGUNA-LBNO Long Baseline Neutrino Beam from the CERN SPS

    CERN Document Server

    Goddard, B; Efthymiopoulos, I; Papaphilippou, Y; Parfenova, A

    2013-01-01

    For the Long Baseline neutrino facility under study at CERN (LAGUNA-LBNO) it is initially planned to extract a 400 GeV beam from the second long straight section in the SPS into the existing transfer channel TT20 leading to the North Area experimental zone, to a new target aligned with a far detector at a distance of 2300 km [1]. In a second phase a new High-Power Proton Synchrotron (HPPS) accelerator is proposed, to give a 2 MW beam at about 50 GeV on the same target. In this paper the required beam transfer systems are outlined, including the new sections of transfer line between the Superconducting Proton Linac (SPL), HP-PS and SPS, and from the SPS to the target, and also the injection and extraction systems in the long straight section of the HPPS. The feasibility of a 4 GeV H- injection system is discussed.

  10. The Long-Term Beam Losses in the CERN Injector Chain

    CERN Document Server

    Gilardoni, Simone; Benedetto, Elena; Damerau, Heiko; Forte, Vincenzo; Giovannozzi, Massimo; Goddard, Brennan; Hancock, Steven; Hanke, Klaus; Huschauer, Alexander; Kowalska, Magdalena; Mcateer, Meghan Jill; Metral, Elias; Mikulec, Bettina; Papaphilippou, Yannis; Rumolo, Giovanni; Sterbini, Guido; Wasef, Raymond; Arduini, Gianluigi; Meddahi, Malika; Chapochnikova, Elena

    2015-01-01

    For the production of the LHC type beams, but also for the high intensity ones, the budget allocated to losses in the CERN injector chain is maintained as tight as possi- ble, in particular to keep as low as possible the activation of the different machine elements. Various beam dynamics effects, like for example beam interaction with betatronic resonances, beam instabilities, but also reduced efficiency of the RF capture processes or RF noise, can produce losses even on a very long time scale. The main different mecha- nisms producing long term losses observed in the CERN injectors, and their cure or mitigation, will be revised.

  11. Cern

    CERN Multimedia

    2009-01-01

    "La réparation de l'accélérateur géant de particules LHC, qui devrait redémarrer mi-novembre aprés une panne de plus d'un an, a coûté 23 millions d'euros, selon un haut responsable du Centre européen de recherche nucléaire (CERN), cité vendredi par les médias espagnols" (1 paragraph)

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

    CERN Multimedia

    2015-01-01

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

  13. High Energy Tests of Advanced Materials for Beam Intercepting Devices at CERN HiRadMat Facility

    CERN Document Server

    Bertarelli, A; Berthome, E; Boccone, V; Carra, F; Cerutti, F; Dallocchio, A; Dos Santos, S; Francon, P; Gentini, L; Guinchard, M; Mariani, N; Masi, A; Moyret, P; Redaeelli, S; Peroni, L; Scapin, M

    2012-01-01

    Predicting by simulations the consequences of LHC particle beams hitting Collimators and other Beam Intercepting Devices (BID) is a fundamental issue for machine protection: this can be done by resorting to highly non-linear numerical tools (Hydrocodes). In order to produce accurate results, these codes require reliable material models that, at the extreme conditions generated by a beam impact, are either imprecise or non-existent. To validate relevant constitutive models or, when unavailable, derive new ones, a comprehensive experimental test foreseeing intense particle beam impacts on six different materials, either already used for present BID or under development for future applications, is being prepared at CERN HiRadMat facility. Tests will be run at medium and high intensity using the SPS proton beam (440 GeV). Material characterization will be carried out mostly in real time relying on embarked instrumentation (strain gauges, microphones, temperature and pressure sensors) and on remote acquisition dev...

  14. The Beam Position System of the CERN Neutrino to Gran Sasso Proton Beam Line

    CERN Document Server

    Bogey, T

    2008-01-01

    The CERN Neutrino to Gran Sasso (CNGS) experiment uses 400GeV protons extracted from the SPS, which travel along 825 meters of beam line before reaching the CNGS target. This beam line is equipped with 23 BPMs capable of measuring both the horizontal and vertical position of the beam. The final BPM is linked to the target station and due to radiation constraints has been designed to work in air. This contribution will give an overview of the BPMs used in the transfer line. It will also provide a detailed explanation of their logarithmic amplifier based acquisition electronics, which consists of an autotriggered sequencer controlling an integrator, the A/D conversion and the Manchester encoded transmission of the digital data to the surface. At the surface the digital data is acquired using the Digital Acquisition Board (DAB) developed by TRIUMF (Canada) for the LHC BPM system. Results from both laboratory measurements and beam measurements during the 2006 CNGS run will also be presented.

  15. Preparation of HEC Serial Modules for Beam and Cold Tests at CERN in 2000

    CERN Multimedia

    Fischer, A.

    2001-01-01

    Photo 1 - Three mated HEC-1 modules in the clean room, prepared for beam tests. Photo 2 - Three mated HEC-1 modules in the clean room, prepared for beam tests. Photo 3 - Three mated HEC-2 modules in the clean room, prepared for beam tests. Photo 4 - Three mated HEC-2 modules in the clean room, prepared for beam tests. Photo 5 - Close-up of the inner-connecting bars of three mated HEC-2 modules, prepared for beam tests. Photo 6 - Mechanical acceptance tests for HEC serial modules at CERN. Photo 7 - Mechanical acceptance tests for HEC serial modules at CERN. Photo 8 - Four HEC-2 modules in the cryostat, prepared for cold tests.

  16. NA61/SHINE facility at the CERN SPS: beams and detector system

    CERN Document Server

    Abgrall, N; Aduszkiewicz, A; Ali, Y; Anticic, T; Antoniou, N; Baatar, B; Bay, F; Blondel, A; Blumer, J; Bogomilov, M; Bogusz, M; Bravar, A; Brzychczyk, J; Bunyatov, S A; Christakoglou, P; Czopowicz, T; Davis, N; Debieux, S; Dembinski, H; Diakonos, F; Di Luise, S; Dominik, W; Drozhzhova, T; Dumarchez, J; Dynowski, K; Engel, R; Efthymiopoulos, I; Ereditato, A; Fabich, A; Feofilov, G A; Fodor, Z; Fulop, A; Gazdzicki, M; Golubeva, M; Grebieszkow, K; Grzeszczuk, A; Guber, F; Haesler, A; Hasegawa, T; Hierholzer, M; Idczak, R; Igolkin, S; Ivashkin, A; Jokovic, D; Kadija, K; Kapoyannis, A; Kaptur, E; Kielczewska, D; Kirejczyk, M; Kisiel, J; Kiss, T; Kleinfelder, S; Kobayashi, T; Kolesnikov, V I; Kolev, D; Kondratiev, V P; Korzenev, A; Koversarski, P; Kowalski, S; Krasnoperov, A; Kurepin, A; Larsen, D; Laszlo, A; Lyubushkin, V V; Mackowiak-Pawlowska, M; Majka, Z; Maksiak, B; Malakhov, A I; Maletic, D; Manglunki, D; Manic, D; Marchionni, A; Marcinek, A; Marin, V; Marton, K; Mathes, H J; Matulewicz, T; Matveev, V; Melkumov, G L; Messina, M; Mrowczynski, St; Murphy, S; Nakadaira, T; Nirkko, M; Nishikawa, K; Palczewski, T; Palla, G; Panagiotou, A D; Paul, T; Peryt, W; Petukhov, O; Pistillo, C; Planeta, R; Pluta, J; Popov, B A; Posiadala, M; Pulawski, S; Puzovic, J; Rauch, W; Ravonel, M; Redij, A; Renfordt, R; Richter-Was, E; Robert, A; Rohrich, D; Rondio, E; Rossi, B; Roth, M; Rubbia, A; Rustamov, A; Rybczynski, M; Sadovsky, A; Sakashita, K; Savic, M; Schmidt, K; Sekiguchi, T; Seyboth, P; Sgalaberna, D; Shibata, M; Sipos, R; Skrzypczak, E; Slodkowski, M; Sosin, Z; Staszel, P; Stefanek, G; Stepaniak, J; Stroebele, H; Susa, T; Szuba, M; Tada, M; Tereshchenko, V; Tolyhi, T; Tsenov, R; Turko, L; Ulrich, R; Unger, M; Vassiliou, M; Veberic, D; Vechernin, V V; Vesztergombi, G; Vinogradov, L; Wilczek, A; Wlodarczyk, Z; Wojtaszek-Szwarz, A; Wyszynski, O; Zambelli, L; Zipper, W

    2014-01-01

    NA61/SHINE (SPS Heavy Ion and Neutrino Experiment) is a multi-purpose experimental facility to study hadron production in hadron-proton, hadron-nucleus and nucleus-nucleus collisions at the CERN Super Proton Synchrotron. It recorded the first physics data with hadron beams in 2009 and with ion beams (secondary 7Be beams) in 2011. NA61/SHINE has greatly profited from the long development of the CERN proton and ion sources and the accelerator chain as well as the H2 beamline of the CERN North Area. The latter has recently been modified to also serve as a fragment separator as needed to produce the Be beams for NA61/SHINE. Numerous components of the NA61/SHINE set-up were inherited from its predecessors, in particular, the last one, the NA49 experiment. Important new detectors and upgrades of the legacy equipment were introduced by the NA61/SHINE Collaboration. This paper describes the state of the NA61/SHINE facility - the beams and the detector system - before the CERN Long Shutdown I, which started in March ...

  17. High duty factor plasma generator for CERN's Superconducting Proton Linac

    International Nuclear Information System (INIS)

    CERN's Linac4 is a 160 MeV linear accelerator currently under construction. It will inject negatively charged hydrogen ions into CERN's PS-Booster. Its ion source is a noncesiated rf driven H- volume source directly inspired from the one of DESY and is aimed to deliver pulses of 80 mA of H- during 0.4 ms at a 2 Hz repetition rate. The Superconducting Proton Linac (SPL) project is part of the luminosity upgrade of the Large Hadron Collider. It consists of an extension of Linac4 up to 5 GeV and is foreseen to deliver protons to a future 50 GeV synchrotron (PS2). For the SPL high power option (HP-SPL), the ion source would deliver pulses of 80 mA of H- during 1.2 ms and operate at a 50 Hz repetition rate. This significant upgrade motivates the design of the new water cooled plasma generator presented in this paper. Its engineering is based on the results of a finite element thermal study of the Linac4 H- plasma generator that identified critical components and thermal barriers. A cooling system is proposed which achieves the required heat dissipation and maintains the original functionality. Materials with higher thermal conductivity are selected and, wherever possible, thermal barriers resulting from low pressure contacts are removed by brazing metals on insulators. The AlN plasma chamber cooling circuit is inspired from the approach chosen for the cesiated high duty factor rf H- source operating at SNS.

  18. High duty factor plasma generator for CERN's Superconducting Proton Linac.

    Science.gov (United States)

    Lettry, J; Kronberger, M; Scrivens, R; Chaudet, E; Faircloth, D; Favre, G; Geisser, J-M; Küchler, D; Mathot, S; Midttun, O; Paoluzzi, M; Schmitzer, C; Steyaert, D

    2010-02-01

    CERN's Linac4 is a 160 MeV linear accelerator currently under construction. It will inject negatively charged hydrogen ions into CERN's PS-Booster. Its ion source is a noncesiated rf driven H(-) volume source directly inspired from the one of DESY and is aimed to deliver pulses of 80 mA of H(-) during 0.4 ms at a 2 Hz repetition rate. The Superconducting Proton Linac (SPL) project is part of the luminosity upgrade of the Large Hadron Collider. It consists of an extension of Linac4 up to 5 GeV and is foreseen to deliver protons to a future 50 GeV synchrotron (PS2). For the SPL high power option (HP-SPL), the ion source would deliver pulses of 80 mA of H(-) during 1.2 ms and operate at a 50 Hz repetition rate. This significant upgrade motivates the design of the new water cooled plasma generator presented in this paper. Its engineering is based on the results of a finite element thermal study of the Linac4 H(-) plasma generator that identified critical components and thermal barriers. A cooling system is proposed which achieves the required heat dissipation and maintains the original functionality. Materials with higher thermal conductivity are selected and, wherever possible, thermal barriers resulting from low pressure contacts are removed by brazing metals on insulators. The AlN plasma chamber cooling circuit is inspired from the approach chosen for the cesiated high duty factor rf H(-) source operating at SNS.

  19. Secondary particle acquisition system for the CERN beam wire scanners upgrade

    International Nuclear Information System (INIS)

    The increasing requirements of CERN experiments make essential the upgrade of beam instrumentation in general, and high accuracy beam profile monitors in particular. The CERN Beam Instrumentation Group has been working during the last years on the Wire Scanners upgrade. These systems cross a thin wire through a circulating beam, the resulting secondary particles produced from beam/wire interaction are detected to reconstruct the beam profile. For the new secondary shower acquisition system, it is necessary to perform very low noise measurements with high dynamic range coverage. The aim is to design a system without tuneable parameters and compatible for any beam wire scanner location at the CERN complex. Polycrystalline chemical vapour deposition diamond detectors (pCVD) are proposed as new detectors for this application because of their radiation hardness, fast response and linearity over a high dynamic range. For the detector readout, the acquisition electronics must be designed to exploit the detector capabilities and perform bunch by bunch measurements at 40MHz. This paper describes the design challenges of such a system, analysing different acquisition possibilities from the signal integrity point of view. The proposed system architecture is shown in detail and the development status presented

  20. Results from the October 2014 CERN test beam of LumiCal

    CERN Document Server

    Borysov, O; Levy, A; Levy, I; Lukic, S; Moron, J; Neagu, A T; Preda, T; Rosenblat, O

    2016-01-01

    A prototype of a luminometer, designed for a future e+e- collider detector, was tested in the CERN PS accelerator T9 testbeam. The objective of this test beam was to demonstrate a multi-plane operation, to study the development of the electromagnetic shower and to compare it with MC simulations.

  1. System Architecture for measuring and monitoring Beam Losses in the Injector Complex at CERN

    CERN Document Server

    Zamantzas, C; Dehning, B; Jackson, S; Kwiatkowski, M; Vigano, W

    2012-01-01

    The strategy for beam setup and machine protection of the accelerators at the European Organisation for Nuclear Research (CERN) is mainly based on its Beam Loss Monitoring (BLM) systems. For their upgrade to higher beam energies and intensities, a new BLM system is under development with the aim of providing faster measurement updates with higher dynamic range and the ability to accept more types of detectors as input compared to its predecessors. In this paper, the architecture of the complete system is explored giving an insight to the design choices made to provide a highly reconfigurable system that is able to fulfil the different requirements of each accelerator using reprogrammable devices.

  2. Simulating the Beam-line at CERN's ISOLDE Experiment

    CERN Document Server

    McGrath, Casey

    2013-01-01

    Maximizing the optical matching along portions of the ISOLDE beam-line and automating this procedure will make it easier for scientists to determine what the strengths of the electrical elds of each beam-line element should be in order to reduce particle loss. Simulations are run using a program called MAD-X, however, certain issues were discovered that hindered an immediate success of the simulations. Specifically, the transfer matrices for electrostatic components like the switchyards, kickers, and electric quadrupoles were missing from the original coding. The primary aim of this project was to design these components using AutoCAD and then extract the transfer matrices using SIMION. Future work will then implement these transfer matrices into the MAD-X code to make the simulations of the beam-line more accurate.

  3. Study of beam transport lines for a biomedical research facility at CERN based on LEIR

    CERN Document Server

    Abler, D; Garonna, A; Peach, K

    2014-01-01

    The Low Energy Ion Ring (LEIR) at CERN has been proposed to provide ion beams with magnetic rigidities up to 6.7 T.m for biomedical research, in parallel to its continued operation for LHC and SPS fixed target physics experiments. In the context of this project, two beamlines are proposed for transporting the extracted beam to future experimental end-stations: a vertical beamline for specific low-energy radiobiological research, and a horizontal beamline for radiobiology and medical physics experimentation. This study presents a first linear-optics design for the delivery of 1–5mm FWHM pencil beams and 5 cm 5 cm homogeneous broad beams to both endstations. High field uniformity is achieved by selection of the central part of a strongly defocused Gaussian beam, resulting in low beam utilisation.

  4. The software for the CERN LEP beam orbit measurement system

    International Nuclear Information System (INIS)

    The Beam Orbit Measurement (BOM) system of LEP consists of 504 pickups, distributed all around the accelerator, that are capable of measuring the positions of the two beams. Their activity has to be synchronized, and the data produced by them have to be collected together, for example to form a 'closed orbit measurement' or a 'trajectory measurement'. On the user side, several clients can access simultaneously the results from this instrument. An automatic acquisition mode, and an 'on request' one, can run in parallel. This results in a very flexible and powerful system. The functionality of the BOM system is fully described, as well as the structure of the software processes which constitute the system, and their interconnections. Problems solved during the implementation are emphasized. (author)

  5. Beam Transfer Line Design for a Plasma Wakefield Acceleration Experiment (AWAKE) at the CERN SPS

    CERN Document Server

    Bracco, C; Brethoux, D; Clerc, V; Goddard, B; Gschwendtner, E; Jensen, L K; Kosmicki, A; Le Godec, G; Meddahi, M; Muggli, P; Mutin, C; Osborne, O; Papastergiou, K; Pardons, A; Velotti, F M; Vincke, H

    2013-01-01

    The world’s first proton driven plasma wakefield acceleration experiment (AWAKE) is presently being studied at CERN. The experimentwill use a high energy proton beam extracted from the SPS as driver. Two possible locations for installing the AWAKE facility were considered: the West Area and the CNGS beam line. The previous transfer line from the SPS to the West Area was completely dismantled in 2005 and would need to be fully re-designed and re-built. For this option, geometric constraints for radiation protection reasons would limit the maximum proton beam energy to 300 GeV. The existing CNGS line could be used by applying only minor changes to the lattice for the final focusing and the interface between the proton beam and the laser, required for plasma ionisation and bunch-modulation seeding. The beam line design studies performed for the two options are presented.

  6. Dispersion Matching of a Space Charge dominated Beam at Injection into the CERN PS Booster

    CERN Document Server

    Hanke, Klaus; Scrivens, Richard

    2005-01-01

    In order to match the dispersion at injection into the CERN PS Booster, the optics of the injection line was simulated using two different codes (MAD and TRACE). The simulations were benchmarked versus experimental results. The model of the line was then used to re-match the dispersion. Experimental results are presented for different optics of the line. Measurements with varying beam current show the independence of the measured quantity of space-charge effects.

  7. The CERN n_TOF Facility: Neutron Beams Performances for Cross Section Measurements

    CERN Document Server

    Chiaveri, E; Andrzejewski, J; Audouin, L; Barbagallo, M; Bécares, V; Bečvář, F; Belloni, F; Berthoumieux, E; Billowes, J; Boccone, V; Bosnar, D; Brugger, M; Calviani, M; Calviño, F; Cano-Ott, D; Carrapiço, C; Cerutti, F; Chin, M; Colonna, N; Cortés, G; Cortés-Giraldo, M A; Diakaki, M; Domingo-Pardo, C; Duran, I; Dressler, R; Dzysiuk, N; Eleftheriadis, C; Ferrari, A; Fraval, K; Ganesan, S; García, A R; Giubrone, G; Gómez-Hornillos, M B; Gonçalves, I F; González-Romero, E; Griesmayer, E; Guerrero, C; Gunsing, F; Gurusamy, P; Hernández-Prieto, A; Jenkins, D G; Jericha, E; Kadi, Y; Käppeler, F; Karadimos, D; Kivel, N; Koehler, P; Kokkoris, M; Krtička, M; Kroll, J; Lampoudis, C; Langer, C; Leal-Cidoncha, E; Lederer, C; Leeb, H; Leong, L S; Losito, R; Mallick, A; Manousos, A; Marganiec, J; Martínez, T; Massimi, C; Mastinu, P F; Mastromarco, M; Meaze, M; Mendoza, E; Mengoni, A; Milazzo, P M; Mingrone, F; Mirea, M; Mondalaers, W; Paradela, C; Pavlik, A; Perkowski, J; Plompen, A; Praena, J; Quesada, J M; Rauscher, T; Reifarth, R; Riego, A; Robles, M S; Roman, F; Rubbia, C; Sabaté-Gilarte, M; Sarmento, R; Saxena, A; Schillebeeckx, P; Schmidt, S; Schumann, D; Tagliente, G; Tain, J L; Tarrío, D; Tassan-Got, L; Tsinganis, A; Valenta, S; Vannini, G; Variale, V; Vaz, P; Ventura, A; Versaci, R; Vermeulen, M J; Vlachoudis, V; Vlastou, R; Wallner, A; Ware, T; Weigand, M; Weiss, C; Wright, T; Žugec, P

    2014-01-01

    This paper presents the characteristics of the existing CERN n\\_TOF neutron beam facility (n\\_TOF-EAR1 with a flight path of 185 meters) and the future one (n\\_TOF EAR-2 with a flight path of 19 meters), which will operate in parallel from Summer 2014. The new neutron beam will provide a 25 times higher neutron flux delivered in 10 times shorter neutron pulses, thus offering more powerful capabilities for measuring small mass, low cross section and/or high activity samples.

  8. Muon flux measurement with silicon detectors in the CERN neutrino beams

    International Nuclear Information System (INIS)

    The neutrino beam installations at the CERN SPS accelerator are described, with emphasis on the beam monitoring systems. Especially the muon flux measurement system is considered in detail, and the calibration procedure and systematic aspects of the measurements are discussed. An introduction is given to the use of silicon semiconductor detectors and their related electronics. Other special chapters concern non-linear phenomena in the silicon detectors, radiation damage in silicon detectors, energy loss and energy deposition in silicon and a review of energy loss phenomena for high energy muons in matter. (orig.)

  9. Proton and Pb ion beam extraction experiments with bent crystals at the CERN-SPS

    CERN Document Server

    Elsener, K; Klem, J T; CERN. Geneva. SPS and LEP Division

    1997-01-01

    Extraction of particle beams from the CERN-SPS using bent silicon crystals is described. A summary of the early results is given. Emphasis is on the recent experiments, in particular on the energy dependence of proton extraction at 14, 120 and 270 GeV. 'U-shaped' crystals of different thickness and with a different miscut angle have been compared at 120 GeV. Non-linear excitation of the beam was used in one experiment, with the aim to achieve larger impact parameters - the results show a particular behaviour in the tails of the beam. Finally, the first experimental result on extraction of a 22 TeV fully stripped Pb ion beam with a bent crystal is also described.

  10. A Micromegas Detector for Neutron Beam Imaging at the n_TOF Facility at CERN

    CERN Document Server

    Belloni, F; Berthoumieux, E; Calviani, M; Chiaveri, E; Colonna, N; Giomataris, Y; Guerrero, C; Gunsing, F; Iguaz, F J; Kebbiri, M; Pancin, J; Papaevangelou, T; Tsinganis, A; Vlachoudis, V; Altstadt, S; Andrzejewski, J; Audouin, L; Barbagallo, M; Bécares, V; Bečvář, F; Billowes, J; Boccone, V; Bosnar, D; Brugger, M; Calviño, F; Cano-Ott, D; Carrapiço, C; Cerutti, F; Chiaveri, E; Chin, M; Cortés, G; Corté-Giraldo, M A; Diakaki, M; Domingo-Pardo, C; Duran, I; Dzysiuk, N; Eleftheriadis, C; Ferrari, A; Fraval, K; Ganesan, S; García, A R; Giubrone, G; Gómez-Hornillos, M B; Gonçalves, I F; González-Romero, E; Griesmayer, E; Gurusamy, P; Jenkins, D G; Jericha, E; Kadi, Y; Käppeler, F; Karadimos, D; Koehler, P; Kokkoris, M; Krtička, M; Kroll, J; Langer, C; Lederer, C; Leeb, H; Leong, L S; Losito, R; Manousos, A; Marganiec, J; Marítnez, T; Massimi, C; Mastinu, P F; Mastromarco, M; Meaze, M; Mendoza, E; Mengoni, A; Milazzo, P M; Mingrone, F; Mirea, M; Mondalaers, W; Paradela, C; Pavlik, A; Perkowski, J; Plompen, A J M; Praena, J; Quesada, J M; Rauscher, T; Reifarth, R; Riego, A; Roman, F; Rubbia, C; Sarmento, R; Schillebeeckx, P; Schmidt, S; Tagliente, G; Tain, J L; Tarrío, D; Tassan-Got, L; Valenta, S; Vannini, G; Variale, V; Vaz, P; Ventura, A; Versaci, R; Vermeulen, M J; Vlastou, R; Wallner, A; Ware, T; Weigand, M; Weiss, C; Wright, T J; Žugec, P

    2014-01-01

    Micromegas (Micro-MEsh Gaseous Structure) detectors are gas detectors consisting of a stack of one ionization and one proportional chamber. A micromesh separates the two communicating regions, where two different electric fields establish respectively a charge drift and a charge multiplication regime. The n\\_TOF facility at CERN provides a white neutron beam (from thermal up to GeV neutrons) for neutron induced cross section measurements. These measurements need a perfect knowlodge of the incident neutron beam, in particular regarding its spatial profile. A position sensitive micromegas detector equipped with a B-10 based neutron/charged particle converter has been extensively used at the n\\_TOF facility for characterizing the neutron beam profile and extracting the beam interception factor for samples of different size. The boron converter allowed to scan the energy region of interest for neutron induced capture reactions as a function of the neutron energy, determined by the time of flight. Experimental ...

  11. Characterization of CALET prototype TASC lead tungstate calorimeter using CERN beam test data

    Science.gov (United States)

    Javaid, Amir

    2013-04-01

    The CALorimetric Electron Telescope (CALET) is a high-energy cosmic ray experiment that will be placed on the International Space Station in 2014. The primary goals of CALET are to measure the cosmic ray electron spectra from 1 GeV to 20 TeV, gamma rays from 10 GeV to 10 TeV, and protons and nuclei from 10 GeV up to 1000 TeV. The detector consists of three main components: a Charge Detector (CHD), Imaging Calorimeter (IMC), and Total Absorption Calorimeter (TASC). The TASC consists of 192 lead tungstate (PbWO4) logs arranged in 12 layers. An understanding of the major characteristics of the TASC is important for accurately determining the incident particle shower energy deposition. In September 2012, a prototype CALET detector was exposed to electron, muon, and proton beams from the Super Proton Synchrotron (SPS) at CERN. Muon beams can be used to determine the detector response to minimum ionizing particles (MIP). In the present paper, we discuss the response of the TASC logs to muon beams as a function of position, and signal attenuation during propagation. Included is a discussion of parameterizations of position-dependent muon energy deposition and signal attenuation functions for the TASC logs based on the CERN beam test data.

  12. Development of high current electron beam generator

    Energy Technology Data Exchange (ETDEWEB)

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

    1997-05-01

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

  13. The transverse and longitudinal beam characteristics of the PHIN photo-injector at CERN

    CERN Document Server

    Mete, Ö; Dabrowski, A; Divall, M; Döbert, S; Egger, D; Elsener, K; Fedosseev, V; Lefèvre, T; Petrarca, M

    2010-01-01

    A new photo-injector, capable to deliver a long pulse train with a high charge per bunch for CTF3, has been designed and installed by a collaboration between LAL, CCLRC and CERN within the framework of the second Joint Research Activity PHIN of the European CARE program. The demonstration of the high charge and the stability along the pulse train are the important goals for CTF3 and the CLIC drive beam. The nominal beam for CTF3 has an average current of 3.5 A, a 1.5 GHz bunch repetation frequency and a pulse length of 1.27 μs (1908 bunches). The existing CTF3 injector consists of a thermionic gun and a subharmonic bunching system. The PHIN photo-injector is being tested in a dedicated test-stand at CERN to replace the existing CTF3 injector that is producing unwanted satellite bunches during the bunching process. A phase-coding scheme is planned to be implemented to the PHIN laser system providing the required beam temporal structure by CTF3. RF photo-injectors are high-brightness, low-emittance electron so...

  14. Test beam results on resistive plate chamber prototype at gamma irradiation facility in CERN

    CERN Document Server

    Chung, C H; Kim, M J; Kim, M S; Kong, D J; Park, K H; Shim, H S; Yun, C W

    1999-01-01

    We report recent results on performances of 2 mm double-gap RPC operated with the CERN SPS X5 120 GeV muon beams under high rate /sup 137/Cs irradiation. We obtained the efficiency and time resolution and other related physical parameters. This was done for a three component gas mixture: (C/sub 2/H/sub 2/F/sub 4/:iso-C/sub 4/H/sub 10 /:SF/sub 6/=95.5:3.0:1.5). The best results were obtained under these conditions and the RPC prototype fulfilled all requirements as muon trigger for LHC. (12 refs).

  15. Preliminary results on μ-e+ events from the CERN wide-band beam technical run

    International Nuclear Information System (INIS)

    During the first technical run of the CERN wide-band neutrino beam, BEBC was operated with a 74 mole-% neon-hydrogen filling under conditions giving thin high density tracks to minimise confusion at interaction vertices. 19 μ-e+ events (including an estimated background of approximately 2 asymmetric Dalitz pairs) have been found in 5,600 +- 400 charged current neutrino interactions, corresponding to a μ-e+/μ- ratio of (0.5 +- 0.2)%. 5 of the 19 events contain vee-zeroes from the primary vertex. (orig.)

  16. Interaction of Super Proton Synchrotron beam with solid copper target: Simulations of future experiments at HiRadMat facility at CERN

    CERN Document Server

    Tahir, N A; Brugger, M; Assmann, R; Shutov, A; Lomonosov, I V; Fortov, V E; Piriz, A R; Deutsch, C; Hoffmann, D H H

    2009-01-01

    In this paper we present numerical simulations of interaction of 450 GeV/c proton beam that is generated by Super Proton Synchrotron (SPS) at CERN, with a solid copper target. These simulations have been carried out using a two-dimensional hydrodynamic computer code, BIG2. This study has been done to assess the damage caused by these highly relativistic protons to equipment including collimators, absorbers and others in case of an uncontrolled accidental release of the beam. In fact a dedicated experimental facility named HiRadMat is under construction at CERN that will allow one to study these problems experimentally. The simulations presented in this paper will be very useful in designing these experiments and later to interpret the experimental results.

  17. Simulations and measurements of beam loss patterns at the CERN Large Hadron Collider

    CERN Document Server

    Bruce, R; Boccone, V; Bracco, C; Brugger, M; Cauchi, M; Cerutti, F; Deboy, D; Ferrari, A; Lari, L; Marsili, A; Mereghetti, A; Mirarchi, D; Quaranta, E; Redaelli, S; Robert-Demolaize, G; Rossi, A; Salvachua, B; Skordis, E; Tambasco, C; Valentino, G; Weiler, T; Vlachoudis, V; Wollmann, D

    2014-01-01

    The CERN Large Hadron Collider (LHC) is designed to collide proton beams of unprecedented energy, in order to extend the frontiers of high-energy particle physics. During the first very successful running period in 2010--2013, the LHC was routinely storing protons at 3.5--4 TeV with a total beam energy of up to 146 MJ, and even higher stored energies are foreseen in the future. This puts extraordinary demands on the control of beam losses. An un-controlled loss of even a tiny fraction of the beam could cause a superconducting magnet to undergo a transition into a normal-conducting state, or in the worst case cause material damage. Hence a multi-stage collimation system has been installed in order to safely intercept high-amplitude beam protons before they are lost elsewhere. To guarantee adequate protection from the collimators, a detailed theoretical understanding is needed. This article presents results of numerical simulations of the distribution of beam losses around the LHC that have leaked out of the co...

  18. New results from the CERN-SPS beam deflection experiments with bent crystals

    Science.gov (United States)

    Baurichter, A.; Kirsebom, K.; Medenwaldt, R.; Møller, S. P.; Worm, T.; Uggerhøj, E.; Mikkelsen, U.; Graftström, P.; Gatignon, L.; Elsener, K.; Doble, N.; Biino, C.; Freund, A.; Vilakazi, Z.; Hage-Ali, M.; Siffert, P.; Clément, M.

    1996-10-01

    Results from five distinct bending experiments performed recently in the H8 beam at CERN are presented. Firstly, deflection of a positive pion beam at 200 GeV/c is compared to the "standard" 450-GeV/c proton beam for a bending angle of 3.1 mrad along the (111) plane in a 50 mm silicon crystal. Second, deflection of negative pions at 200 GeV/c is investigated for the same crystal, for incidence along the (111) plane as well as the axis. Small deflection effects are seen, but no negative particles are bent through the full bending angle of the crystal. Third, the first results from beam deflection at high energy using a germanium crystal are shown. Slightly higher deflection efficiencies than for silicon are seen for large bending angles, but significantly smaller than expected for such a crystal with higher atomic number. Fourth, deflection efficiencies using a strongly irradiated silicon crystal have been measured for the first time, and a small reduction in efficiency is seen in the irradiated region. Finally, deflection of positive particles using axial alignment of a bent silicon crystal has been investigated at 450 GeV/c. Qualitatively similar behaviour as in previous experiments at 12 GeV/c is seen; the beam splits into several beams corresponding to the different planes, and even weak planes are observed.

  19. Supervision Software for the Integration of the Beam Interlock System with the CERN Accelerator Complex

    CERN Document Server

    Audrain, M; Dragu, M; Fuchsberger, K; Garnier, JC; Gorzawski, AA; Koza, M; Krol, K; Moscatelli, A; Puccio, B; Stamos, K; Zerlauth, M

    2014-01-01

    The Accelerator complex at the European Organisation for Nuclear Research (CERN) is composed of many systems which are required to function in a valid state to ensure safe beam operation. One key component of machine protection, the Beam Interlock System (BIS), was designed to interface critical systems around the accelerator chain, provide fast and reliable transmission of beam dump requests and trigger beam extraction in case of malfunctioning of equipment systems or beam losses. Numerous upgrades of accelerator and controls components during the Long Shutdown 1 (LS1) are followed by subsequent software updates that need to be thoroughly validated before the restart of beam operation in 2015. In parallel, the ongoing deployments of the BIS hardware in the PS booster (PSB) and the future LINAC4 give rise to new requirements for the related controls and monitoring software due to their fast cycle times. This paper describes the current status and ongoing work as well as the long-term vision for the integratio...

  20. Generating stable tractor beams with dielectric metasurfaces

    Science.gov (United States)

    Pfeiffer, Carl; Grbic, Anthony

    2015-03-01

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

  1. OAM beams from incomplete computer generated holograms

    CERN Document Server

    Zambale, Niña Angelica F; Hermosa, Nathaniel

    2016-01-01

    In this letter we show that optical beams with orbital angular momentum (OAM) can be generated even with incomplete computer generated holograms (CGH). These holograms are made such that random portions of it do not contain any information. We observe that although the beams produced with these holograms are less intense, these beams maintain their shape and that their topological charges are not affected. Furthermore, we show that superposition of two or more beams can be created using separate incomplete CGHs interspersed together. Our result is significant especially since most method to generate beams with OAM for various applications rely on pixelated devices or optical elements with imperfections.

  2. Theses. Beam studies for the CERN antiproton decelerator and a new interpretation of the resonance theory for betatron motion

    Energy Technology Data Exchange (ETDEWEB)

    De Ninno, G

    1999-07-01

    The two parts of the thesis are a mission-oriented task devoted to solve some practical problems of the Antiproton Decelerator (AD) project at CERN, and a theoretical study leading to a new method for representing and compensating betatron resonances. The AD is a new machine (at the moment under commissioning at CERN) that will allow the collection and the deceleration of an antiproton beam from 3.5 GeV/c down to 100 MeV/c (the momentum favoured for the foreseen physics experiments). The need to employ the AD magnets over a wide range required a careful study of their characteristics. The presence of a solenoid inside the AD electron cooling device generates linear coupling between the transverse degrees of freedom of the single-particle motion. Coupling can lead to operational problems and therefore a compensation scheme had tobe designed. The long-standing problem has been solved of how to establish a relationship between the two standard methods for dealing with linear coupling: the matrix approach and the Hamiltonian approach. The bridge was built by including in the Hamiltonian approach in the high frequency part of the perturbative Hamiltonian due to coupling. The procedure was generalised to the nonlinear case and, a new method was proposed for dealing both with linear and nonlinear resonances. (author)

  3. Theses. Beam studies for the CERN antiproton decelerator and a new interpretation of the resonance theory for betatron motion

    International Nuclear Information System (INIS)

    The two parts of the thesis are a mission-oriented task devoted to solve some practical problems of the Antiproton Decelerator (AD) project at CERN, and a theoretical study leading to a new method for representing and compensating betatron resonances. The AD is a new machine (at the moment under commissioning at CERN) that will allow the collection and the deceleration of an antiproton beam from 3.5 GeV/c down to 100 MeV/c (the momentum favoured for the foreseen physics experiments). The need to employ the AD magnets over a wide range required a careful study of their characteristics. The presence of a solenoid inside the AD electron cooling device generates linear coupling between the transverse degrees of freedom of the single-particle motion. Coupling can lead to operational problems and therefore a compensation scheme had to be designed. The long-standing problem has been solved of how to establish a relationship between the two standard methods for dealing with linear coupling: the matrix approach and the Hamiltonian approach. The bridge was built by including in the Hamiltonian approach in the high frequency part of the perturbative Hamiltonian due to coupling. The procedure was generalised to the nonlinear case and, a new method was proposed for dealing both with linear and nonlinear resonances. (author)

  4. Validation of the Read Out Electronics for the CMS Muon Drift Chambers at Tests Beam in CERN/GIF

    CERN Document Server

    Fernández, C; Fouz-Iglesias, M C; Marin, J; Oller, J C; Willmott, C

    2002-01-01

    Part of the readout system for the CMS muon drift chambers has been tested in test beams at CERN/GIF. Read Out Board (ROB) and HPTD have been validated with signals from a real muon beam, with an structure and flux similar to LHC operating conditions and using one of the chambers produced in CIEMAT already located in the test beam area under normal gas and voltage conditions. (Author) 5 refs.

  5. Validation of the Read Out Electronics for the CMS Muon Drift Chambers at Tests Beam in CERN/GIF

    International Nuclear Information System (INIS)

    Part of the readout system for the CMS muon drift chambers has been tested in test beams at CERN/GIF. Read Out Board (ROB) and HPTD have been validated with signals from a real muon beam, with an structure and flux similar to LHC operating conditions and using one of the chambers produced in CIEMAT already located in the test beam area under normal gas and voltage conditions. (Author) 5 refs

  6. The Radiological Situation in the Beam-Cleaning Sections of the CERN Large Hadron Collider (LHC)

    CERN Document Server

    Brugger, Markus; Stevenson, Graham

    2003-01-01

    This thesis contributes to radiological assessments of the design and operation of the Large Hadron Collider currently under construction at CERN. In particular, the scope of this thesis is to examine the beam cleaning insertions - two of the main loss regions of the LHC where beam particles which would otherwise cause unwanted losses at different places of the machine are purposely intercepted. Two critical issues with regard to the protection of personnel and environment are studied: remanent dose rates due to induced radioactivity and airborne radioactivity. Although a detailed estimate of remanent dose rates is important for an optimization of later maintenance interventions only very limited information on remanent dose rates to be expected around the collimators was available so far. This thesis is an attempt to extend the knowledge considerably, especially by applying a new calculational method. Since this new approach is used for the first time in the design of the LHC a careful benchmarking with expe...

  7. Laser ion beam production at CERN-ISOLDE: New features - More possibilities

    Science.gov (United States)

    Rothe, S.; Day Goodacre, T.; Fedorov, D. V.; Fedosseev, V. N.; Marsh, B. A.; Molkanov, P. L.; Rossel, R. E.; Seliverstov, M. D.; Veinhard, M.; Wendt, K. D. A.

    2016-06-01

    This article summarizes the current specifications and the latest features of the CERN-ISOLDE resonance ionization laser ion source (RILIS). This includes a description of the optical layout and the newly designed reference system. The ionization schemes for the laser ionized beams at ISOLDE are tabulated, including six new elements. All RILIS schemes are also made publicly available in the RILIS elements on-line database. Finally, we announce a paradigm shift in RILIS operation - the combination of a machine protection and a monitoring and control system has enabled on-call operation of the laser ion source for selected beams in 2014 and has become the standard mode of operation in 2015.

  8. Electron beam parallel X-ray generator

    Science.gov (United States)

    Payne, P.

    1967-01-01

    Broad X ray source produces a highly collimated beam of low energy X rays - a beam with 2 to 5 arc minutes of divergence at energies between 1 and 6 keV in less than 5 feet. The X ray beam is generated by electron bombardment of a target from a large area electron gun.

  9. High Charge PHIN Photo Injector at CERN with Fast Phase switching within the Bunch Train for Beam Combination

    CERN Document Server

    Csatari Divall, M; Bolzon, B; Bravin, E; Chevallay, E; Dabrowski, A; Doebert, S; Drozdy, A; Fedosseev, V; Hessler, C; Lefevre, T; Livesley, S; Losito, R; Olvegaard, M; Petrarca, M; Rabiller, A N; Egger, D; Mete, O

    2011-01-01

    The high charge PHIN photo-injector was developed within the framework of the European CARE program to provide an alternative to the drive beam thermionic gun in the CTF3 (CLIC Test Facility) at CERN. In PHIN 1908 electron bunches are delivered with bunch spacing of 1.5 GHz and 2.33 nC charge per bunch. Furthermore the drive beam generated by CTF3 requires several fast 180 deg phase-shifts with respect to the 1.5 GHz bunch repetition frequency in order to allow the beam combination scheme developed at CTF3. A total of 8 subtrains, each 140 ns long and shifted in phase with respect to each other, have to be produced with very high phase and amplitude stability. A novel fiber modulator based phase-switching technique developed on the laser system provides this phase-shift between two consecutive pulses much faster and cleaner than the base line scheme, where a thermionic electron gun and sub-harmonic bunching are used. The paper describes the fiber-based switching system and the measurements verifying the schem...

  10. Simulations and measurements of beam loss patterns at the CERN Large Hadron Collider

    Science.gov (United States)

    Bruce, R.; Assmann, R. W.; Boccone, V.; Bracco, C.; Brugger, M.; Cauchi, M.; Cerutti, F.; Deboy, D.; Ferrari, A.; Lari, L.; Marsili, A.; Mereghetti, A.; Mirarchi, D.; Quaranta, E.; Redaelli, S.; Robert-Demolaize, G.; Rossi, A.; Salvachua, B.; Skordis, E.; Tambasco, C.; Valentino, G.; Weiler, T.; Vlachoudis, V.; Wollmann, D.

    2014-08-01

    The CERN Large Hadron Collider (LHC) is designed to collide proton beams of unprecedented energy, in order to extend the frontiers of high-energy particle physics. During the first very successful running period in 2010-2013, the LHC was routinely storing protons at 3.5-4 TeV with a total beam energy of up to 146 MJ, and even higher stored energies are foreseen in the future. This puts extraordinary demands on the control of beam losses. An uncontrolled loss of even a tiny fraction of the beam could cause a superconducting magnet to undergo a transition into a normal-conducting state, or in the worst case cause material damage. Hence a multistage collimation system has been installed in order to safely intercept high-amplitude beam protons before they are lost elsewhere. To guarantee adequate protection from the collimators, a detailed theoretical understanding is needed. This article presents results of numerical simulations of the distribution of beam losses around the LHC that have leaked out of the collimation system. The studies include tracking of protons through the fields of more than 5000 magnets in the 27 km LHC ring over hundreds of revolutions, and Monte Carlo simulations of particle-matter interactions both in collimators and machine elements being hit by escaping particles. The simulation results agree typically within a factor 2 with measurements of beam loss distributions from the previous LHC run. Considering the complex simulation, which must account for a very large number of unknown imperfections, and in view of the total losses around the ring spanning over 7 orders of magnitude, we consider this an excellent agreement. Our results give confidence in the simulation tools, which are used also for the design of future accelerators.

  11. Measured and simulated heavy-ion beam loss patterns at the CERN Large Hadron Collider

    Science.gov (United States)

    Hermes, P. D.; Bruce, R.; Jowett, J. M.; Redaelli, S.; Salvachua Ferrando, B.; Valentino, G.; Wollmann, D.

    2016-05-01

    The Large Hadron Collider (LHC) at CERN pushes forward to new regimes in terms of beam energy and intensity. In view of the combination of very energetic and intense beams together with sensitive machine components, in particular the superconducting magnets, the LHC is equipped with a collimation system to provide protection and intercept uncontrolled beam losses. Beam losses could cause a superconducting magnet to quench, or in the worst case, damage the hardware. The collimation system, which is optimized to provide a good protection with proton beams, has shown a cleaning efficiency with heavy-ion beams which is worse by up to two orders of magnitude. The reason for this reduced cleaning efficiency is the fragmentation of heavy-ion beams into isotopes with a different mass to charge ratios because of the interaction with the collimator material. In order to ensure sufficient collimation performance in future ion runs, a detailed theoretical understanding of ion collimation is needed. The simulation of heavy-ion collimation must include processes in which 82+208Pb ions fragment into dozens of new isotopes. The ions and their fragments must be tracked inside the magnetic lattice of the LHC to determine their loss positions. This paper gives an overview of physical processes important for the description of heavy-ion loss patterns. Loss maps simulated by means of the two tools ICOSIM [1,2] and the newly developed STIER (SixTrack with Ion-Equivalent Rigidities) are compared with experimental data measured during LHC operation. The comparison shows that the tool STIER is in better agreement.

  12. Status and Planned Experiments of the Hiradmat Pulsed Beam Material Test Facility at CERN SPS

    Energy Technology Data Exchange (ETDEWEB)

    Charitonidis, Nikolaos [CERN; Efthymiopoulos, Ilias [CERN; Fabich, Adrian [CERN; Meddahi, Malika [CERN; Gianfelice-Wendt, Eliana [Fermilab

    2015-06-01

    HiRadMat (High Irradiation to Materials) is a facility at CERN designed to provide high-intensity pulsed beams to an irradiation area where material samples as well as accelerator component assemblies (e.g. vacuum windows, shock tests on high power targets, collimators) can be tested. The beam parameters (SPS 440 GeV protons with a pulse energy of up to 3.4 MJ, or alternatively lead/argon ions at the proton equivalent energy) can be tuned to match the needs of each experiment. It is a test area designed to perform single pulse experiments to evaluate the effect of high-intensity pulsed beams on materials in a dedicated environment, excluding long-time irradiation studies. The facility is designed for a maximum number of 1016 protons per year, in order to limit the activation of the irradiated samples to acceptable levels for human intervention. This paper will demonstrate the possibilities for research using this facility and go through examples of upcoming experiments scheduled in the beam period 2015/2016.

  13. Status and Planned Experiments of the Hiradmat Pulsed Beam Material Test Facility at CERN SPS

    CERN Document Server

    Charitonidis, Nikolaos; Fabich, Adrian; Meddahi, Malika; Gianfelice-Wendt, Eliana

    2015-01-01

    HiRadMat (High Irradiation to Materials) is a facility at CERN designed to provide high-intensity pulsed beams to an irradiation area where material samples as well as accelerator component assemblies (e.g. vacuum windows, shock tests on high power targets, collimators) can be tested. The beam parameters (SPS 440 GeV protons with a pulse energy of up to 3.4 MJ, or alternatively lead/argon ions at the proton equivalent energy) can be tuned to match the needs of each experiment. It is a test area designed to perform single pulse experiments to evaluate the effect of high-intensity pulsed beams on materials in a dedicated environment, excluding long-time irradiation studies. The facility is designed for a maximum number of 1016 protons per year, in order to limit the activation of the irradiated samples to acceptable levels for human intervention. This paper will demonstrate the possibilities for research using this facility and go through examples of upcoming experiments scheduled in the beam period 2015/201...

  14. Beam tests of CALET with BBM electronics and STM at CERN-SPS

    Science.gov (United States)

    Tamura, Tadahisa

    We have been developing flight hardware of CALET (CALorimetric Electron Telescope) to observe electrons, gamma rays, and nuclei at the Japanese Experiment Module “Kibo” Exposed Facility (JEM-EF) on the International Space Station (ISS). The main calorimeter of CALET consists of a charge detector (CHD) to identify particles by charge, an imaging calorimeter (IMC) to determine incident angles and shower starting points, and a total absorption calorimeter (TASC) to measure energies and to discriminate electromagnetic particles from nuclei. We carried out beam experiments at CERN-SPS to confirm consistency between our simulation and beam test data. It is important for performance check and flight data analyses. We assembled a Beam Test Model detector by using BBM (Bread Board Model) of front end electronics and STM (Structure and Thermal Model) of CHD, IMC, and TASC for electron/proton runs in 2012. We made ion runs mainly to test CHD readout with BBM front end electronics in 2013. Basic results of the beam tests will be reported here.

  15. Studies of the beam extraction system of the GTS-LHC electron cyclotron resonance ion source at CERN

    Energy Technology Data Exchange (ETDEWEB)

    Toivanen, V., E-mail: ville.aleksi.toivanen@cern.ch; Küchler, D. [European Organization for Nuclear Research (CERN), 1211 Geneva 23 (Switzerland)

    2016-02-15

    The 14.5 GHz GTS-LHC Electron Cyclotron Resonance Ion Source (ECRIS) provides multiply charged heavy ion beams for the CERN experimental program. The GTS-LHC beam formation has been studied extensively with lead, argon, and xenon beams with varied beam extraction conditions using the ion optical code IBSimu. The simulation model predicts self-consistently the formation of triangular and hollow beam structures which are often associated with ECRIS ion beams, as well as beam loss patterns which match the observed beam induced markings in the extraction region. These studies provide a better understanding of the properties of the extracted beams and a way to diagnose the extraction system performance and limitations, which is otherwise challenging due to the lack of direct diagnostics in this region and the limited availability of the ion source for development work.

  16. Studies of the beam extraction system of the GTS-LHC electron cyclotron resonance ion source at CERN

    International Nuclear Information System (INIS)

    The 14.5 GHz GTS-LHC Electron Cyclotron Resonance Ion Source (ECRIS) provides multiply charged heavy ion beams for the CERN experimental program. The GTS-LHC beam formation has been studied extensively with lead, argon, and xenon beams with varied beam extraction conditions using the ion optical code IBSimu. The simulation model predicts self-consistently the formation of triangular and hollow beam structures which are often associated with ECRIS ion beams, as well as beam loss patterns which match the observed beam induced markings in the extraction region. These studies provide a better understanding of the properties of the extracted beams and a way to diagnose the extraction system performance and limitations, which is otherwise challenging due to the lack of direct diagnostics in this region and the limited availability of the ion source for development work

  17. Studies of the beam extraction system of the GTS-LHC electron cyclotron resonance ion source at CERN.

    Science.gov (United States)

    Toivanen, V; Küchler, D

    2016-02-01

    The 14.5 GHz GTS-LHC Electron Cyclotron Resonance Ion Source (ECRIS) provides multiply charged heavy ion beams for the CERN experimental program. The GTS-LHC beam formation has been studied extensively with lead, argon, and xenon beams with varied beam extraction conditions using the ion optical code IBSimu. The simulation model predicts self-consistently the formation of triangular and hollow beam structures which are often associated with ECRIS ion beams, as well as beam loss patterns which match the observed beam induced markings in the extraction region. These studies provide a better understanding of the properties of the extracted beams and a way to diagnose the extraction system performance and limitations, which is otherwise challenging due to the lack of direct diagnostics in this region and the limited availability of the ion source for development work. PMID:26932095

  18. Studies of the beam extraction system of the GTS-LHC electron cyclotron resonance ion source at CERN.

    Science.gov (United States)

    Toivanen, V; Küchler, D

    2016-02-01

    The 14.5 GHz GTS-LHC Electron Cyclotron Resonance Ion Source (ECRIS) provides multiply charged heavy ion beams for the CERN experimental program. The GTS-LHC beam formation has been studied extensively with lead, argon, and xenon beams with varied beam extraction conditions using the ion optical code IBSimu. The simulation model predicts self-consistently the formation of triangular and hollow beam structures which are often associated with ECRIS ion beams, as well as beam loss patterns which match the observed beam induced markings in the extraction region. These studies provide a better understanding of the properties of the extracted beams and a way to diagnose the extraction system performance and limitations, which is otherwise challenging due to the lack of direct diagnostics in this region and the limited availability of the ion source for development work.

  19. Studies of the beam extraction system of the GTS-LHC electron cyclotron resonance ion source at CERN

    Science.gov (United States)

    Toivanen, V.; Küchler, D.

    2016-02-01

    The 14.5 GHz GTS-LHC Electron Cyclotron Resonance Ion Source (ECRIS) provides multiply charged heavy ion beams for the CERN experimental program. The GTS-LHC beam formation has been studied extensively with lead, argon, and xenon beams with varied beam extraction conditions using the ion optical code IBSimu. The simulation model predicts self-consistently the formation of triangular and hollow beam structures which are often associated with ECRIS ion beams, as well as beam loss patterns which match the observed beam induced markings in the extraction region. These studies provide a better understanding of the properties of the extracted beams and a way to diagnose the extraction system performance and limitations, which is otherwise challenging due to the lack of direct diagnostics in this region and the limited availability of the ion source for development work.

  20. Beam-Generated Detector Backgrounds at CESR

    OpenAIRE

    Henderson, Stuart; Cinabro, David

    2000-01-01

    The CESR/CLEO Phase II interaction region is described. The operational experience with beam-generated detector backgrounds is reviewed. The status of our understanding of beam-generated detector backgrounds at CESR is described and comparisons of background measurements with simulation predictions are presented.

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

    Directory of Open Access Journals (Sweden)

    A.Ju. Karpenko

    2012-10-01

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

  2. Real-Time System Supervision for the LHC Beam Loss Monitoring System at CERN

    CERN Document Server

    Zamantzas, C; Effinger, E; Emery, J; Jackson, S

    2014-01-01

    The strategy for machine protection and quench prevention of the Large Hadron Collider (LHC) at the European Organisation for Nuclear Research (CERN) is mainly based on the Beam Loss Monitoring (BLM) system. The LHC BLM system is one of the most complex and large instrumentation systems deployed in the LHC. In addition to protecting the collider, the system also needs to provide a means of diagnosing machine faults and deliver feedback of the losses to the control room as well as to several systems for their setup and analysis. In order to augment the dependability of the system several layers of supervision has been implemented internally and externally to the system. This paper describes the different methods employed to achieve the expected availability and system fault detection.

  3. Study of muon-induced neutron production using accelerator muon beam at CERN

    International Nuclear Information System (INIS)

    Cosmogenic muon-induced neutrons are one of the most problematic backgrounds for various underground experiments for rare event searches. In order to accurately understand such backgrounds, experimental data with high-statistics and well-controlled systematics is essential. We performed a test experiment to measure muon-induced neutron production yield and energy spectrum using a high-energy accelerator muon beam at CERN. We successfully observed neutrons from 160 GeV/c muon interaction on lead, and measured kinetic energy distributions for various production angles. Works towards evaluation of absolute neutron production yield is underway. This work also demonstrates that the setup is feasible for a future large-scale experiment for more comprehensive study of muon-induced neutron production

  4. 10 Orders of Magnitude Current Measurement Digitisers for the CERN Beam Loss Systems

    CERN Document Server

    Vigano, W; Dehning, B; Kwiatkowski, M; Venturini, G G; Zamantzas, C

    2014-01-01

    A wide range current digitizer card is needed for the acquisition module of the beam loss monitoring systems in the CERN Injector Complex. The fully differential frequency converter allows measuring positive and negative input currents with a resolution of 31nA in an integration window of 2μs. Increasing the integration window, the dynamic range covers 2•1010 were the upper part of the range is converted by measuring directly the voltage drop on a resistor. The key elements of this design are the fully differential integrator and the switches operated by an FPGA. The circuit is designed to avoid any dead time in the acquisition and reliability and failsafe operational considerations are main design goals. The circuit will be discussed in detail and lab and field measurements will be shown.

  5. 10 orders of magnitude current measurement digitisers for the CERN beam loss systems

    Science.gov (United States)

    Viganò, W.; Alsdorf, M.; Dehning, B.; Kwiatkowski, M.; Venturini, G. G.; Zamantzas, C.

    2014-02-01

    A wide range current digitizer card is needed for the acquisition module of the beam loss monitoring systems in the CERN Injector Complex. The fully differential frequency converter allows measuring positive and negative input currents with a resolution of 31 nA in an integration window of 2 μs. Increasing the integration window, the dynamic range covers 21010 were the upper part of the range is converted by measuring directly the voltage drop on a resistor. The key elements of this design are the fully differential integrator and the switches operated by an FPGA. The circuit is designed to avoid any dead time in the acquisition and reliability and failsafe operational considerations are main design goals. The circuit will be discussed in detail and lab and field measurements will be shown.

  6. Simulation of the CERN GTS-LHC ECR ion source extraction system with lead and argon ion beams

    CERN Document Server

    Toivanen, V; Küchler, D; Lombardi, A; Scrivens, R; Stafford-Haworth, J

    2014-01-01

    A comprehensive study of beam formation and beam transport has been initiated in order to improve the performance of the CERN heavy ion injector, Linac3. As part of this study, the ion beam extraction system of the CERN GTS-LHC 14.5 GHz Electron Cyclotron Resonance Ion Source (ECRIS) has been modelled with the ion optical code IBSimu. The simulations predict self-consistently the triangular and hollow beam structures which are often observed experimentally with ECRIS ion beams. The model is used to investigate the performance of the current extraction system and provides a basis for possible future improvements. In addition, the extraction simulation provides a more realistic representation of the initial beam properties for the beam transport simulations, which aim to identify the performance bottle necks along the Linac3 low energy beam transport. The results of beam extraction simulations with Pb and Ar ion beams from the GTS-LHC will be presented and compared with experimental observations.

  7. Detailed magnetic model simulations of the H- injection chicane magnets for the CERN PS Booster Upgrade, including eddy currents and influence on beam dynamics

    CERN Document Server

    Benedetto, E; Borburgh, J; Carli, C; Martini, M; Forte, V

    2014-01-01

    The CERN PS Booster will be upgraded with an H- injection system. The chicanemagnets for the injection bump ramp-down in 5 ms and generate eddy currents in the inconel vacuum chamber which perturb the homogeneity of the magnetic field. The multipolar field components are extracted from 3D OPERA simulations and are included in the lattice model. The -beating correction is computed all along the ramp and complete tracking simulations including space-charge are performed to evaluate the impact of these perturbations and correction on beam dynamics.

  8. The CERN antiproton target: hydrocode analysis of its core material dynamic response under proton beam impact

    CERN Document Server

    Martin, Claudio Torregrosa; Calviani, Marco; Muñoz-Cobo, José-Luis

    2016-01-01

    Antiprotons are produced at CERN by colliding a 26 GeV/c proton beam with a fixed target made of a 3 mm diameter, 55 mm length iridium core. The inherent characteristics of antiproton production involve extremely high energy depositions inside the target when impacted by each primary proton beam, making it one of the most dynamically demanding among high energy solid targets in the world, with a rise temperature above 2000 {\\deg}C after each pulse impact and successive dynamic pressure waves of the order of GPa's. An optimized redesign of the current target is foreseen for the next 20 years of operation. As a first step in the design procedure, this numerical study delves into the fundamental phenomena present in the target material core under proton pulse impact and subsequent pressure wave propagation by the use of hydrocodes. Three major phenomena have been identified, (i) the dominance of a high frequency radial wave which produces destructive compressive-to-tensile pressure response (ii) The existence of...

  9. Effect of the Various Impedances on Longitudinal Beam Stability in the CERN SPS

    CERN Document Server

    Lasheen, Alexandre; Repond, Joël; Shaposhnikova, Elena

    2016-01-01

    The High Luminosity (HL)-LHC project at CERN aims at a luminosity increase by a factor ten and one of the necessary ingredients is doubling the bunch intensity to 2.4x10¹¹ ppb for beams with 25 ns bunch spacing. Many improvements are already foreseen in the frame of the LHC Injector Upgrade (LIU) project, but probably this intensity would still not be reachable in the SPS due to longitudinal instabilities. Recently a lot of effort went into finding the impedance sources of the instabilities. Particle simulations based on the latest SPS impedance model are now able to reproduce the measured instability thresholds and were used to determine the most critical impedance sources by removing them one by one from the model. It was found that impedance of vacuum flanges and of the already damped 630 MHz HOM of the main RF system gave for 72 bunches the comparable intensity thresholds. Possible intensity gains are defined for realistic impedance modifications and for various beam configurations (number of bunches, l...

  10. CERN antiproton target: Hydrocode analysis of its core material dynamic response under proton beam impact

    Science.gov (United States)

    Martin, Claudio Torregrosa; Perillo-Marcone, Antonio; Calviani, Marco; Muñoz-Cobo, José-Luis

    2016-07-01

    Antiprotons are produced at CERN by colliding a 26 GeV /c proton beam with a fixed target made of a 3 mm diameter, 55 mm length iridium core. The inherent characteristics of antiproton production involve extremely high energy depositions inside the target when impacted by each primary proton beam, making it one of the most dynamically demanding among high energy solid targets in the world, with a rise temperature above 2000 °C after each pulse impact and successive dynamic pressure waves of the order of GPa's. An optimized redesign of the current target is foreseen for the next 20 years of operation. As a first step in the design procedure, this numerical study delves into the fundamental phenomena present in the target material core under proton pulse impact and subsequent pressure wave propagation by the use of hydrocodes. Three major phenomena have been identified, (i) the dominance of a high frequency radial wave which produces destructive compressive-to-tensile pressure response (ii) The existence of end-of-pulse tensile waves and its relevance on the overall response (iii) A reduction of 44% in tensile pressure could be obtained by the use of a high density tantalum cladding.

  11. Comparison of electromagnetic and hadronic models generated using Geant 4 with antiproton dose measured in CERN

    Directory of Open Access Journals (Sweden)

    Mohammad Bagher Tavakoli

    2015-01-01

    Full Text Available After proposing the idea of antiproton cancer treatment in 1984 many experiments were launched to investigate different aspects of physical and radiobiological properties of antiproton, which came from its annihilation reactions. One of these experiments has been done at the European Organization for Nuclear Research known as CERN using the antiproton decelerator. The ultimate goal of this experiment was to assess the dosimetric and radiobiological properties of beams of antiprotons in order to estimate the suitability of antiprotons for radiotherapy. One difficulty on this way was the unavailability of antiproton beam in CERN for a long time, so the verification of Monte Carlo codes to simulate antiproton depth dose could be useful. Among available simulation codes, Geant4 provides acceptable flexibility and extensibility, which progressively lead to the development of novel Geant4 applications in research domains, especially modeling the biological effects of ionizing radiation at the sub-cellular scale. In this study, the depth dose corresponding to CERN antiproton beam energy by Geant4 recruiting all the standard physics lists currently available and benchmarked for other use cases were calculated. Overall, none of the standard physics lists was able to draw the antiproton percentage depth dose. Although, with some models our results were promising, the Bragg peak level remained as the point of concern for our study. It is concluded that the Bertini model with high precision neutron tracking (QGSP_BERT_HP is the best to match the experimental data though it is also the slowest model to simulate events among the physics lists.

  12. Comparison of electromagnetic and hadronic models generated using Geant 4 with antiproton dose measured in CERN.

    Science.gov (United States)

    Tavakoli, Mohammad Bagher; Reiazi, Reza; Mohammadi, Mohammad Mehdi; Jabbari, Keyvan

    2015-01-01

    After proposing the idea of antiproton cancer treatment in 1984 many experiments were launched to investigate different aspects of physical and radiobiological properties of antiproton, which came from its annihilation reactions. One of these experiments has been done at the European Organization for Nuclear Research known as CERN using the antiproton decelerator. The ultimate goal of this experiment was to assess the dosimetric and radiobiological properties of beams of antiprotons in order to estimate the suitability of antiprotons for radiotherapy. One difficulty on this way was the unavailability of antiproton beam in CERN for a long time, so the verification of Monte Carlo codes to simulate antiproton depth dose could be useful. Among available simulation codes, Geant4 provides acceptable flexibility and extensibility, which progressively lead to the development of novel Geant4 applications in research domains, especially modeling the biological effects of ionizing radiation at the sub-cellular scale. In this study, the depth dose corresponding to CERN antiproton beam energy by Geant4 recruiting all the standard physics lists currently available and benchmarked for other use cases were calculated. Overall, none of the standard physics lists was able to draw the antiproton percentage depth dose. Although, with some models our results were promising, the Bragg peak level remained as the point of concern for our study. It is concluded that the Bertini model with high precision neutron tracking (QGSP_BERT_HP) is the best to match the experimental data though it is also the slowest model to simulate events among the physics lists.

  13. The new vertical neutron beam line at the CERN n-TOF facility design and outlook on the performance

    Energy Technology Data Exchange (ETDEWEB)

    Weiß, C., E-mail: christina.weiss@cern.ch [European Organization for Nuclear Research (CERN), Geneva (Switzerland); Chiaveri, E.; Girod, S.; Vlachoudis, V.; Aberle, O. [European Organization for Nuclear Research (CERN), Geneva (Switzerland); Barros, S. [Instituto Tecnológico e Nuclear, Instituto Superior Técnico, Universidade Técnica de Lisboa, Lisboa (Portugal); Bergström, I. [European Organization for Nuclear Research (CERN), Geneva (Switzerland); Berthoumieux, E. [Commissariat à l’Énergie Atomique (CEA) Saclay – Irfu, Gif-sur-Yvette (France); Calviani, M. [European Organization for Nuclear Research (CERN), Geneva (Switzerland); Guerrero, C.; Sabaté-Gilarte, M. [Universidad de Sevilla (Spain); European Organization for Nuclear Research (CERN), Geneva (Switzerland); Tsinganis, A. [European Organization for Nuclear Research (CERN), Geneva (Switzerland); National Technical University of Athens (NTUA) (Greece); Andrzejewski, J. [Uniwersytet Łódzki, Lodz (Poland); Audouin, L. [Centre National de la Recherche Scientifique/IN2P3 – IPN, Orsay (France); Bacak, M. [Atominstitut, Technische Universität Wien (Austria); Balibrea-Correa, J. [Centro de Investigaciones Energeticas Medioambientales y Tecnológicas (CIEMAT), Madrid (Spain); Barbagallo, M. [Istituto Nazionale di Fisica Nucleare, Bari (Italy); Bécares, V. [Centro de Investigaciones Energeticas Medioambientales y Tecnológicas (CIEMAT), Madrid (Spain); and others

    2015-11-01

    At the neutron time-of-flight facility n-TOF at CERN a new vertical beam line was constructed in 2014, in order to extend the experimental possibilities at this facility to an even wider range of challenging cross-section measurements of interest in astrophysics, nuclear technology and medical physics. The design of the beam line and the experimental hall was based on FLUKA Monte Carlo simulations, aiming at maximizing the neutron flux, reducing the beam halo and minimizing the background from neutrons interacting with the collimator or back-scattered in the beam dump. The present paper gives an overview on the design of the beam line and the relevant elements and provides an outlook on the expected performance regarding the neutron beam intensity, shape and energy resolution, as well as the neutron and photon backgrounds.

  14. The CTF3 team who performed the first electron beam recombination in an isochronous ring at CERN.

    CERN Multimedia

    Maximilien Brice

    2002-01-01

    Photo 0210004_1: Part of CTF3 collaboration. From left to right: T. Ekelof (Uppsala), A. Gallo (LNF), P. Royer (Lausanne), F. Tecker (CERN), L. Rinolfi (CERN), A. Ferrari (Uppsala), R. Corsini (CERN), S. Quaglia, (LNF). Photo 0210004_2: A. Ferrari (left), T. Ekelof (middle) and A. Rydberg (right), from Uppsala University, Sweden, standing where the phase monitor HR.PHM60 is installed. Photo 0210004_4: A. Gallo (LNF) standing in front of the RF deflector designed by INFN-Frascati. Photo 0210004_7: The team who designed the CTF3 complex starting from the existing LEP Pre-Injector. From left to right L. Rinolfi, A. Ferrari, F. Tecker (standing up) and R. Corsini, P. Royer (kneeling down) in front of the electron transfer line between the linac and the combiner ring. Photo 0210004_9: The CTF3 team who performed the first electron beam recombination in an isochronous ring at CERN. From left to right, L. Rinolfi, P. Royer, F. Tecker, R. Corsini standing up in front of the two RF deflectors built at CERN and working...

  15. Spatial and temporal beam profile monitor with nanosecond resolution for CERN's Linac4 and Superconducting Proton Linac

    CERN Document Server

    Hori, M

    2008-01-01

    The Linac4, now being developed at CERN, will provide 160-MeV H- beams of high intensity . Before this beam can be injected into the CERN Proton Synchrotron Booster or future Superconducting Proton Linac for further acceleration, some sequences of 500-ps-long micro-bunches must be removed from it, using a beam chopper. These bunches, if left in the beam, would fall outside the longitudinal acceptance of the accelerators and make them radioactive. We developed a monitor to measure the time structure and spatial profile of this chopped beam, with respective resolutions and . Its large active area and dynamic range also allows investigations of beam halos. The ion beam first struck a carbon foil, and secondary electrons emerging from the foil were accelerated by a series of parallel grid electrodes. These electrons struck a phosphor screen, and the resulting image of the scintillation light was guided to a thermoelectrically cooled, charge-coupled device camera. The time resolution was attained by applying high-...

  16. Optical vortex beam generator at nanoscale level

    Science.gov (United States)

    Garoli, Denis; Zilio, Pierfrancesco; Gorodetski, Yuri; Tantussi, Francesco; de Angelis, Francesco

    2016-07-01

    Optical beams carrying orbital angular momentum (OAM) can find tremendous applications in several fields. In order to apply these particular beams in photonic integrated devices innovative optical elements have been proposed. Here we are interested in the generation of OAM-carrying beams at the nanoscale level. We design and experimentally demonstrate a plasmonic optical vortex emitter, based on a metal-insulator-metal holey plasmonic vortex lens. Our plasmonic element is shown to convert impinging circularly polarized light to an orbital angular momentum state capable of propagating to the far-field. Moreover, the emerging OAM can be externally adjusted by switching the handedness of the incident light polarization. The device has a radius of few micrometers and the OAM beam is generated from subwavelength aperture. The fabrication of integrated arrays of PVLs and the possible simultaneous emission of multiple optical vortices provide an easy way to the large-scale integration of optical vortex emitters for wide-ranging applications.

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

    CERN Multimedia

    Charitonidis, N; Efthymiopoulos, I

    2014-01-01

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

  18. Microwave bessel beams generation using guided modes

    KAUST Repository

    Salem, Mohamed

    2011-06-01

    A novel method is devised for Bessel beams generation in the microwave regime. The beam is decomposed in terms of a number of guided transverse electric modes of a metallic waveguide. Modal expansion coefficients are computed from the modal power orthogonality relation. Excitation is achieved by means of a number of inserted coaxial loop antennas, whose currents are calculated from the excitation coefficients of the guided modes. The efficiency of the method is evaluated and its feasibility is discussed. Obtained results can be utilized to practically realize microwave Bessel beam launchers. © 2006 IEEE.

  19. Cryogenic Current Comparator as Low Intensity Beam Current Monitor in the CERN Antiproton Decelerators

    CERN Document Server

    Fernandes, M; Soby, L; Welsch, CP

    2013-01-01

    In the low-energy Antiproton Decelerator (AD) and the future Extra Low ENergy Antiproton (ELENA) rings at CERN, an absolute measurement of the beam intensity is essential to monitor any losses during the deceleration and cooling phases. However, existing DC current transformers can hardly reach the μA level, while at the AD and ELENA currents can be as low as 100 nA. A Cryogenic Current Comparator (CCC) based on a superconducting quantum interference device (SQUID) is currently being designed and shall be installed in the AD and ELENA machines. It should meet the following specifications: A current resolution smaller than 10 nA, a dynamic range covering currents between 100 nA and 1 mA, as well as a bandwidth from DC to 1 kHz. Different design options are being considered, including the use of low or high temperature superconductor materials, different CCC shapes and dimensions, different SQUID characteristics, as well as electromagnetic shielding requirements. In this contribution we present first results f...

  20. Exposure of CR39 Stacks to Oxygen and Sulphur Beams at the CERN-SPS

    CERN Multimedia

    2002-01-01

    We plan to expose 8 stacks of CR39 sheets to oxygen and sulphur ions of 60 and 200~GeV at the CERN-SPS.\\\\ \\\\ The main purpose of the exposures is the calibration of the CR39 sheets used for a large area experimental search for magnetic monopoles at the Gran Sasso Laboratory (experiment MACRO). \\\\ \\\\ The stacks have 20~layers of CR39, each layer 13~cm~x~7~cm and 1.4~mm thick. A copper absorber is located after the first 6 layers. \\\\ \\\\ We require exposures of about 2000 tracks per cm$^2$ over the entire area of the stack with a uniform illumination. The standard beam used for the emulsion experiments is normally adequate for this purpose.\\\\ \\\\ We have performed one exposure to sulphur ions. The etched tracks have been measured automatically with the Elbeck image analyser system. We measured the incoming sulphur ions as well as the nuclear fragments produced in the copper absorber. Clean separation among the peaks due to the various fragments is obtained (there is no indication of nuclei with fractional electri...

  1. Managing the Real-time Behaviour of a Particle Beam Factory The CERN Proton Synchrotron Complex and its Timing System Principles

    CERN Document Server

    Bau, J C; Lewis, J; Philippe, J

    1998-01-01

    In the CERN 26 Gev Proton Synchrotron (PS) accelerator network, super-cycles are defined as sequences of different kinds of beams produced repetitively [Fig.1]. Each of these beams is characterised by attributes such as particle type, beam energy, its route through the accelerator network, and the final end user. The super-cycle is programmed by means of an editor through which the operational requirements of the physics programme can be described. Each beam in the normal sequence may later be replaced by a set of spare beams automatically depending on software and hardware interlocks and requests presented to the Master Timing Generator (MTG [Glos. 1]). The MTG calculates at run time how each beam is to be manufactured, and sends a telegram [Glos. 3] message to each accelerator, just before each cycle, describing what it should be doing now and during the next cycle. These messages, together with key machine timing events and clocks are encoded onto a timing distribution drop net where they are distributed a...

  2. Digital generation of partially coherent vortex beams.

    Science.gov (United States)

    Perez-Garcia, Benjamin; Yepiz, Adad; Hernandez-Aranda, Raul I; Forbes, Andrew; Swartzlander, Grover A

    2016-08-01

    We present an experimental technique to generate partially coherent vortex beams with an arbitrary azimuthal index using only a spatial light modulator. Our approach is based on digitally simulating the intrinsic randomness of broadband light passing through a spiral phase plate. We illustrate the versatility of the technique by generating partially coherent beams with different coherence lengths and orbital angular momentum content, without any moving optical device. Consequently, we study its cross-correlation function in a wavefront folding interferometer. The comparison with theoretical predictions yields excellent agreement. PMID:27472596

  3. Particle Identification with Cherenkov detectors in the 2011 CALICE Tungsten Analog Hadronic Calorimeter Test Beam at the CERN SPS

    CERN Document Server

    Dannheim, D; Klempt, W; Lucaci Timoce, A; van der Kraaij, E

    2013-01-01

    In 2011 the CALICE Tungsten Analog Hadronic Calorimeter prototype (W-AHCAL) was exposed to mixed beams of electrons, pions, kaons and protons with momenta from 10 to 300 GeV in the CERN SPS H8 beam line. The selection of pion, kaon and proton samples is based on the information obtained from two Cherenkov threshold counters. This note presents the strategy for the particle identification, as well as the calibration, operation and analysis of the Cherenkov counters. Efficiency and sample-purity estimates are given for the data selected for the W-AHCAL data analysis.

  4. Beam formation in CERNs cesiated surfaces and volume H- ion sources

    Science.gov (United States)

    Mochalskyy, Serhiy; Lettry, Jacques; Minea, Tiberiu

    2016-08-01

    At CERN, a high performance negative ion (NI) source is required for the 160 MeV H- linear accelerator named Linac4. The source should deliver 80 mA H- ion beams within an emittance of 0.25 mm·mrad. For this purpose two ion sources were developed: IS01 is based on the NI volume production and IS02 provides additional NI by surface production via H interaction on a cesiated Molybdenum plasma electrode. The development of negative ion sources for Linac4 is accompanied by modelling activities. ONIX code has been modified and adapted to investigate the transport of NI and electrons in the extraction region of the CERN negative ion sources. The simulated results from modeling of IS01 and IS02 extraction regions, which were obtained in 2012 during source commissioning, are presented and benchmarked with experimental measurements obtained after 2013. The formation of the plasma meniscus and the screening of the extraction field by the source plasma are discussed. The NI production is compared between two types of sources, the first one based on volume production only and the second one encompassing NI cesiated surface production. For the IS02 source, different states of conditioning were simulated by changing the NI emission flux from the plasma electrode and Cs+ density in the bulk plasma region. The numerical results show that in low work function regime, with high NI surface emission rate of 3000 A m-2 and Cs-density of nCs+ = 3.8 × 1016 m-3, the total extracted NI current could reach ~80 mA. At the less favorable Cs-coverage, when the surface NI emission rate becomes significantly lower, namely 300 A m-2 with nCs+ = 3.3 × 1015 m-3, the total extracted NI current only reaches ~20 mA. A good agreement between simulation and experimental results is observed in terms of extracted NI current for both extraction systems, including the case of reversed extraction potential that corresponds to positive (H+) ion extraction.

  5. Catenary nanostructures as compact Bessel beam generators.

    Science.gov (United States)

    Li, Xiong; Pu, Mingbo; Zhao, Zeyu; Ma, Xiaoliang; Jin, Jinjin; Wang, Yanqin; Gao, Ping; Luo, Xiangang

    2016-01-01

    Non-diffracting Bessel beams, including zero-order and high-order Bessel Beams which carry orbital angular momentum (OAM), enable a variety of important applications in optical micromanipulation, sub-diffraction imaging, high speed photonics/quantum communication, etc. The commonly used ways to create Bessel beams, including an axicon or a digital hologram written to a spatial light modulator (SLM), have great challenges to operate at the nanoscale. Here we theoretically design and experimentally demonstrate one kind of planar Bessel beam generators based on metasurfaces with analytical structures perforated in ultra-thin metallic screens. Continuous phase modulation between 0 to 2π is realized with a single element. In addition, due to the dispersionless phase shift stemming from spin-orbit interaction, the proposed device can work in a wide wavelength range. The results may find applications in future optical communication, nanofabrication and super-resolution imaging, etc. PMID:26843142

  6. Holographic generation of highly twisted electron beams

    CERN Document Server

    Grillo, Vincenzo; Mafakheri, Erfan; Frabboni, Stefano; Karimi, Ebrahim; Boyd, Robert W

    2014-01-01

    Free electrons can possess an intrinsic orbital angular momentum, similar to those in an electron cloud, upon free-space propagation. The wavefront corresponding to the electron's wavefunction forms a helical structure with a number of twists given by the \\emph{angular speed}. Beams with a high number of twists are of particular interest because they carry a high magnetic moment about the propagation axis. Among several different techniques, electron holography seems to be a promising approach to shape a \\emph{conventional} electron beam into a helical form with large values of angular momentum. Here, we propose and manufacture a nano-fabricated phase hologram for generating a beam of this kind with an orbital angular momentum up to 200$\\hbar$. Based on a novel technique the value of orbital angular momentum of the generated beam are measured, then compared with simulations. Our work, apart from the technological achievements, may lead to a way of generating electron beams with a high quanta of magnetic momen...

  7. Reliability of the Beam Loss Monitors System for the Large Hadron Collider at CERN

    CERN Document Server

    Guaglio, G; Santoni, C

    2005-01-01

    The energy stored in the Large Hadron Collider is unprecedented. The impact of the beam particles can cause severe damage on the superconductive magnets, resulting in significant downtime for repairing. The Beam Loss Monitors System (BLMS) detects the secondary particles shower of the lost beam particles and initiates the extraction of the beam before any serious damage to the equipment can occur. This thesis defines the BLMS specifications in term of reliability. The main goal is the design of a system minimizing both the probability to not detect a dangerous loss and the number of false alarms generated. The reliability theory and techniques utilized are described. The prediction of the hazard rates, the testing procedures, the Failure Modes Effects and Criticalities Analysis and the Fault Tree Analysis have been used to provide an estimation of the probability to damage a magnet, of the number of false alarms and of the number of generated warnings. The weakest components in the BLMS have been pointed out....

  8. High Energy Beam Impact Tests on a LHC Tertiary Collimator at CERN HiRadMat Facility

    CERN Document Server

    Cauchi, M; Assmann, R; Bertarelli, A; Carra, F; Dallocchio, A; Deboy, D; Redaelli, S; Rossi, A; Salvachua, B; Lari, L; Mollicone, P; Sammut, N

    2013-01-01

    The correct functioning of the collimation system is crucial to safelyoperate the LHC. The requirements to handle high intensity beams can be demanding. In this respect, investigating the consequences of LHC particle beams hitting tertiary collimators (TCTs) in the experimental regions is a fundamental issue for machine protection. An experimental test was designed to investigate the robustness and effects of beam accidents on a fully assembled collimator, based on accident scenarios in the LHC. This experiment, carried out at the CERN HiRadMat (High Irradiation to Materials) facility, involved 440 GeV beam impacts of different intensities on the jaws of a horizontal TCT. This paper presents the experimental setup and the preliminary results obtained together with some first outcomes from visual inspection.

  9. Structured Beam Generation with a Single Metasurface

    OpenAIRE

    Yue, Fuyong; Wen, Dandan; Xin, Jingtao; Gerardot, Brian; Li, Jensen; Chen, Xianzhong

    2016-01-01

    Despite a plethora of applications ranging from quantum memories to high-resolution lithography, the current technologies to generate vector vortex beams (VVBs) suffer from less efficient energy use, poor resolution, low damage threshold, bulky size and complicated experimental setup, preventing further practical applications. We propose and experimentally demonstrate an approach to generate VVBs with a single metasurface by locally tailoring phase and transverse polarization distribution. Th...

  10. Generation of a hollow laser beam by a multimode fiber

    Institute of Scientific and Technical Information of China (English)

    Hongyu Ma; Huadong Cheng; Wenzhuo Zhang; Liang Liu; Yuzhu Wang

    2007-01-01

    A simple method to generate a hollow laser beam by multimode fiber is reported. A dark hollow laser beam is generated from a multimode fiber and the dependence of the output beam profile on the incident angle of laser beam is analyzed. The results show that this hollow laser beam can be used to trap and guide cold atoms.

  11. CERN Neutrinos to Gran Sasso (CNGS) Results from Commissioning

    CERN Document Server

    Meddahi, M; Elsener, K; Gschwendtner, E; Herr, Werner; Kain, V; Lamont, M; Wenninger, J

    2007-01-01

    The CNGS project (CERN Neutrinos to Gran Sasso) aims at directly detecting nm - nt oscillations. An intense nm beam is generated at CERN and directed towards LNGS (Laboratori Nazionali del Gran Sasso) in Italy where nt will be detected in large and complex detectors. An overview of the CNGS beam facility is given. Results from the primary and secondary beam line commissioning performed in summer 2006 are presented. Measurements are compared with expectations.

  12. The OPERA experiment in the CERN to Gran Sasso neutrino beam

    Science.gov (United States)

    Acquafredda, R.; Adam, T.; Agafonova, N.; Alvarez Sanchez, P.; Ambrosio, M.; Anokhina, A.; Aoki, S.; Ariga, A.; Ariga, T.; Arrabito, L.; Aufranc, C.; Autiero, D.; Badertscher, A.; Bagulya, A.; Baussan, E.; Bergnoli, A.; Bersani Greggio, F.; Bertolin, A.; Besnier, M.; Biaré, D.; Bick, D.; Blin, S.; Borer, K.; Boucrot, J.; Boutigny, D.; Boyarkin, V.; Bozza, C.; Brugière, T.; Brugnera, R.; Brunetti, G.; Buontempo, S.; Campagne, J. E.; Carlus, B.; Carrara, E.; Cazes, A.; Chaussard, L.; Chernyavsky, M.; Chiarella, V.; Chon-Sen, N.; Chukanov, A.; Ciesielski, R.; Consiglio, L.; Cozzi, M.; D'Amato, G.; Dal Corso, F.; D'Ambrosio, N.; Damet, J.; de La Taille, C.; DeLellis, G.; Déclais, Y.; Descombes, T.; DeSerio, M.; Di Capua, F.; Di Ferdinando, D.; Di Giovanni, A.; Di Marco, N.; Di Troia, C.; Dick, N.; Dmitrievski, S.; Dominjon, A.; Dracos, M.; Duchesneau, D.; Dulach, B.; Dusini, S.; Ebert, J.; Efthymiopoulos, I.; Egorov, O.; Elsener, K.; Enikeev, R.; Ereditato, A.; Esposito, L. S.; Fanin, C.; Favier, J.; Felici, G.; Ferber, T.; Fini, R.; Fournier, L.; Franceschi, A.; Frekers, D.; Fukuda, T.; Fukushima, C.; Galkin, V. I.; Galkin, V. A.; Gallet, R.; Gardien, S.; Garfagnini, A.; Gaudiot, G.; Giacomelli, G.; Giorgini, M.; Girerd, C.; Goellnitz, C.; Goeltzenlichter, T.; Goldberg, J.; Golubkov, D.; Gornushkin, Y.; Grapton, J.-N.; Grella, G.; Grianti, F.; Gschwendtner, E.; Guerin, C.; Guler, M.; Gustavino, C.; Guyonnet, J.-L.; Hagner, C.; Hamane, T.; Hara, T.; Hauger, M.; Hess, M.; Hierholzer, M.; Hoshino, K.; Ieva, M.; Incurvati, M.; Jakovcic, K.; Janicsko Csathy, J.; Janutta, B.; Jollet, C.; Juget, F.; Kazuyama, M.; Kim, S. H.; Khovansky, N.; Kimura, M.; Klicek, B.; Knuesel, J.; Kodama, K.; Kolev, D.; Komatsu, M.; Kose, U.; Krasnoperov, A.; Kreslo, I.; Krumstein, Z.; Kutsenov, V. V.; Kuznetsov, V. A.; Laktineh, I.; Lavy, M.; Lazzaro, C.; Le, T. D.; LeFlour, T.; Lenkeit, J.; Lewis, J.; Lieunard, S.; Ljubicic, A.; Longhin, A.; Lutter, G.; Malgin, A.; Manai, K.; Mandrioli, G.; Marotta, A.; Marteau, J.; Martin-Chassard, G.; Matveev, V.; Mauri, N.; Meddahi, M.; Meisel, F.; Meregaglia, A.; Meschini, A.; Messina, M.; Migliozzi, P.; Monacelli, P.; Monteiro, I.; Moreau, F.; Morishima, K.; Moser, U.; Muciaccia, M. T.; Mugnier, P.; Naganawa, N.; Nakamura, M.; Nakano, T.; Napolitano, T.; Nikitina, V.; Niwa, K.; Nonoyama, Y.; Nozdrin, A.; Ogawa, S.; Olchevski, A.; Orlandi, D.; Orlova, G.; Osedlo, V.; Ossetski, D.; Paniccia, M.; Paoloni, A.; Park, B. D.; Park, I. G.; Pastore, A.; Patrizii, L.; Pellegrino, L.; Pennacchio, E.; Pessard, H.; Pilipenko, V.; Pistillo, C.; Polukhina, N.; Pozzato, M.; Pretzl, K.; Publichenko, P.; Pupilli, F.; Raux, L.; Repellin, J. P.; Rescigno, R.; Rizhikov, D.; Roganova, T.; Romano, G.; Rosa, G.; Rostovtseva, I.; Rubbia, A.; Russo, A.; Ryasny, V.; Ryazhskaya, O.; Sadovski, A.; Sanelli, C.; Sato, O.; Sato, Y.; Saveliev, V.; Sazhina, G.; Schembri, A.; Schmidt Parzefall, W.; Schroeder, H.; Schütz, H. U.; Schuler, J.; Scotto Lavina, L.; Serrano, J.; Shibuya, H.; Simone, S.; Sioli, M.; Sirignano, C.; Sirri, G.; Song, J. S.; Spinetti, M.; Stanco, L.; Starkov, N.; Stipcevic, M.; Strauss, T.; Strolin, P.; Sugonyaev, V.; Takahashi, S.; Talochkin, V.; Tenti, M.; Tereschenko, V.; Terranova, F.; Tezuka, I.; Tioukov, V.; Tolun, P.; Tsarev, V.; Tsenov, R.; Tufanli, S.; Ugolino, U.; Ushida, N.; Van Beek, G.; Verguilov, V.; Viant, T.; Vilain, P.; Vladimirov, M.; Votano, L.; Vuilleumier, J. L.; Waelchli, T.; Weber, M.; Wilquet, G.; Wonsak, B.; Wurtz, J.; Yakushev, V.; Yoon, C. S.; Zaitsev, Y.; Zghiche, A.; Zimmermann, R.

    2009-04-01

    The OPERA neutrino oscillation experiment has been designed to prove the appearance of ντ in a nearly pure νμ beam (CNGS) produced at CERN and detected in the underground Hall C of the Gran Sasso Laboratory, 730 km away from the source. In OPERA, τ leptons resulting from the interaction of ντ are produced in target units called bricks made of nuclear emulsion films interleaved with lead plates. The OPERA target contains 150000 of such bricks, for a total mass of 1.25 kton, arranged into walls interleaved with plastic scintillator strips. The detector is split into two identical supermodules, each supermodule containing a target section followed by a magnetic spectrometer for momentum and charge measurement of penetrating particles. Real time information from the scintillators and the spectrometers provide the identification of the bricks where the neutrino interactions occurred. The candidate bricks are extracted from the walls and, after X-ray marking and an exposure to cosmic rays for alignment, their emulsion films are developed and sent to the emulsion scanning laboratories to perform the accurate scan of the event. In this paper, we review the design and construction of the detector and of its related infrastructures, and report on some technical performances of the various components. The construction of the detector started in 2003 and it was completed in Summer 2008. The experiment is presently in the data taking phase. The whole sequence of operations has proven to be successful, from triggering to brick selection, development, scanning and event analysis.

  13. Generation and study of relativistic electron beam

    International Nuclear Information System (INIS)

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

  14. Determination of the Neutron Fluence, the Beam Characteristics and the Backgrounds at the CERN-PS TOF Facility

    CERN Multimedia

    Leal, L C; Kitis, G; Guber, K H; Quaranta, A; Koehler, P E

    2002-01-01

    In the scope of our programme we propose to start in July 2000 with measurements on elements of well known cross sections, in order to check the reliability of the whole experimental installation at the CERN-TOF facility. These initial exploratory measurements will provide the key-parameters required for the further experimentation at the CERN-TOF neutron beam. The neutron fluence and energy resolution will be determined as a function of the neutron kinetic energy by reproducing standard capture and fission cross sections. The measurements of capture cross sections on elements with specific cross section features will allow to us to disentangle the different components of backgrounds and estimate their level in the experimental area. The time-energy calibration will be determined and monitored with a set of monoenergetic filters as well as by the measurements of elements with resonance-dominated cross sections. Finally, in this initial phase the behaviour of several detectors scheduled in successive measureme...

  15. Acoustic source for generating an acoustic beam

    Energy Technology Data Exchange (ETDEWEB)

    Vu, Cung Khac; Sinha, Dipen N.; Pantea, Cristian

    2016-05-31

    An acoustic source for generating an acoustic beam includes a housing; a plurality of spaced apart piezo-electric layers disposed within the housing; and a non-linear medium filling between the plurality of layers. Each of the plurality of piezoelectric layers is configured to generate an acoustic wave. The non-linear medium and the plurality of piezo-electric material layers have a matching impedance so as to enhance a transmission of the acoustic wave generated by each of plurality of layers through the remaining plurality of layers.

  16. Beam Tests and Plans for the CERN PS Transverse Damper System

    CERN Document Server

    Blas, A; Sterbini, G

    2013-01-01

    The CERN Proton Synchrotron (CPS) has been running without any transverse damping equipment since 1998, thanks to the stabilizing effect of the linear coupling applied between horizontal and vertical planes. \

  17. Development of a High Dynamic Range Beam Position Measurement system using Logarithmic Amplifiers for the SPS at CERN

    CERN Document Server

    Gonzalez, J L; Deplano, C; Savioz, J J

    2013-01-01

    A new Front-End electronics, based on Logarithmic Amplifiers, is currently being developed for the CERN SPS Multi Orbit POsition System (MOPOS). The aim is to resolve the multi-batch structure of the beams and cope with their large intensity range (> 70 dB). Position and intensity signals are digitized in the Front-End electronics installed in the tunnel. The data are then transmitted over a serial fibre-optic link to a VME Digital Acquisition board located in surface buildings. A first prototype, equipped with a calibration system, has been successfully tested on the SPS under different beam conditions, including single bunch, 25 ns and 50 ns bunch trains. The system architecture and the first beam measurements are reported in this paper

  18. First implementation of transversely split proton beams in the CERN Proton Synchrotron for the fixed-target physics programme

    CERN Document Server

    Borburgh, J; Gilardoni, S; Giovannozzi, M; Hernalsteens, C; Hourican, M; Huschauer, A; Kahle, K; Le Godec, G; Michels, O; Sterbini, G

    2016-01-01

    A new extraction technique has been studied at the CERN Proton Synchrotron with a view of using it for the fixed-target physics programme at the Super Proton Synchrotron. The extraction scheme is based on advanced concepts of non-linear beam dynamics: prior to extraction a particle beam is split into several beamlets in a transverse plane by crossing a stable resonance, which allows extracting the beamlets over multiple turns. The principle of the extraction, the detail of its implementation, and the progress of the beam commissioning over the years are discussed here. More importantly, the results obtained during the first period of successful use for the physics programme are presented, focusing on the performance analysis of the novel extraction.

  19. Simulation study of electron cloud induced instabilities and emittance growth for the CERN Large Hadron Collider proton beam

    CERN Document Server

    Benedetto, Elena; Schulte, Daniel; Rumolo, Giovanni

    2005-01-01

    The electron cloud may cause transverse single-bunch instabilities of proton beams such as those in the Large Hadron Collider (LHC) and the CERN Super Proton Synchrotron (SPS). We simulate these instabilities and the consequent emittance growth with the code HEADTAIL, which models the turn-by-turn interaction between the cloud and the beam. Recently some new features were added to the code, in particular, electric conducting boundary conditions at the chamber wall, transverse feedback, and variable beta functions. The sensitivity to several numerical parameters has been studied by varying the number of interaction points between the bunch and the cloud, the phase advance between them, and the number of macroparticles used to represent the protons and the electrons. We present simulation results for both LHC at injection and SPS with LHC-type beam, for different electron-cloud density levels, chromaticities, and bunch intensities. Two regimes with qualitatively different emittance growth are observed: above th...

  20. Reliability of the beam loss monitors system for the large hadron collider at CERN

    International Nuclear Information System (INIS)

    The energy stored in the Large Hadron Collider is unprecedented. The impact of the beam particles can cause severe damage on the superconductive magnets, resulting in significant downtime for repairing. The Beam Loss Monitors System (BLMS) detects the secondary particles shower of the lost beam particles and initiates the extraction of the beam before any serious damage to the equipment can occur. This thesis defines the BLMS specifications in term of reliability. The main goal is the design of a system minimizing both the probability to not detect a dangerous loss and the number of false alarms generated. The reliability theory and techniques utilized are described. The prediction of the hazard rates, the testing procedures, the Failure Modes Effects and Criticalities Analysis and the Fault Tree Analysis have been used to provide an estimation of the probability to damage a magnet, of the number of false alarms and of the number of generated warnings. The weakest components in the BLMS have been pointed out. The reliability figures of the BLMS have been calculated using a commercial software package (Isograph.). The effect of the variation of the parameters on the obtained results has been evaluated with a sensitivity analysis. The reliability model has been extended by the results of radiation tests. Design improvements, like redundant optical transmission, have been implemented in an iterative process. The proposed system is compliant with the reliability requirements. The model uncertainties are given by the limited knowledge of the thresholds levels of the superconductive magnets and of the locations of the losses along the ring. The implemented model allows modifications of the system, following the measuring of the hazard rates during the LHC life. It can also provide reference numbers to other accelerators which will implement similar technologies. (author)

  1. Second-harmonic generation with Bessel beams

    Science.gov (United States)

    Shatrovoy, Oleg

    We present the results of a numerical simulation tool for modeling the second-harmonic generation (SHG) interaction experienced by a diffracting beam. This code is used to study the simultaneous frequency and spatial profile conversion of a truncated Bessel beam that closely resembles a higher-order mode (HOM) of an optical fiber. SHG with Bessel beams has been investigated in the past and was determined have limited value because it is less efficient than SHG with a Gaussian beam in the undepleted pump regime. This thesis considers, for the first time to the best of our knowledge, whether most of the power from a Bessel-like beam could be converted into a second-harmonic beam (full depletion), as is the case with a Gaussian beam. We study this problem because using HOMs for fiber lasers and amplifiers allows reduced optical intensities, which mitigates nonlinearities, and is one possible way to increase the available output powers of fiber laser systems. The chief disadvantage of using HOM fiber amplifiers is the spatial profile of the output, but this can be transformed as part of the SHG interaction, most notably to a quasi-Gaussian profile when the phase mismatch meets the noncollinear criteria. We predict, based on numerical simulation, that noncollinear SHG (NC-SHG) can simultaneously perform highly efficient (90%) wavelength conversion from 1064 nm to 532 nm, as well as concurrent mode transformation from a truncated Bessel beam to a Gaussian-like beam (94% overlap with a Gaussian) at modest input powers (250 W, peak power or continuous-wave operation). These simulated results reveal two attractive features -- the feasibility of efficiently converting HOMs of fibers into Gaussian-like beams, and the ability to simultaneously perform frequency conversion. Combining the high powers that are possible with HOM fiber amplifiers with access to non-traditional wavelengths may offer significant advantages over the state of the art for many important applications

  2. Upgrade of the beam extraction system of the GTS-LHC electron cyclotron resonance ion source at CERN

    Energy Technology Data Exchange (ETDEWEB)

    Toivanen, V., E-mail: ville.aleksi.toivanen@cern.ch; Bellodi, G.; Dimov, V.; Küchler, D.; Lombardi, A. M.; Maintrot, M. [European Organization for Nuclear Research (CERN), 1211 Geneva 23 (Switzerland)

    2016-02-15

    Linac3 is the first accelerator in the heavy ion injector chain of the Large Hadron Collider (LHC), providing multiply charged heavy ion beams for the CERN experimental program. The ion beams are produced with GTS-LHC, a 14.5 GHz electron cyclotron resonance ion source, operated in afterglow mode. Improvement of the GTS-LHC beam formation and beam transport along Linac3 is part of the upgrade program of the injector chain in preparation for the future high luminosity LHC. A mismatch between the ion beam properties in the ion source extraction region and the acceptance of the following Low Energy Beam Transport (LEBT) section has been identified as one of the factors limiting the Linac3 performance. The installation of a new focusing element, an einzel lens, into the GTS-LHC extraction region is foreseen as a part of the Linac3 upgrade, as well as a redesign of the first section of the LEBT. Details of the upgrade and results of a beam dynamics study of the extraction region and LEBT modifications will be presented.

  3. Upgrade of the beam extraction system of the GTS-LHC electron cyclotron resonance ion source at CERN

    International Nuclear Information System (INIS)

    Linac3 is the first accelerator in the heavy ion injector chain of the Large Hadron Collider (LHC), providing multiply charged heavy ion beams for the CERN experimental program. The ion beams are produced with GTS-LHC, a 14.5 GHz electron cyclotron resonance ion source, operated in afterglow mode. Improvement of the GTS-LHC beam formation and beam transport along Linac3 is part of the upgrade program of the injector chain in preparation for the future high luminosity LHC. A mismatch between the ion beam properties in the ion source extraction region and the acceptance of the following Low Energy Beam Transport (LEBT) section has been identified as one of the factors limiting the Linac3 performance. The installation of a new focusing element, an einzel lens, into the GTS-LHC extraction region is foreseen as a part of the Linac3 upgrade, as well as a redesign of the first section of the LEBT. Details of the upgrade and results of a beam dynamics study of the extraction region and LEBT modifications will be presented

  4. Upgrade of the beam extraction system of the GTS-LHC electron cyclotron resonance ion source at CERN.

    Science.gov (United States)

    Toivanen, V; Bellodi, G; Dimov, V; Küchler, D; Lombardi, A M; Maintrot, M

    2016-02-01

    Linac3 is the first accelerator in the heavy ion injector chain of the Large Hadron Collider (LHC), providing multiply charged heavy ion beams for the CERN experimental program. The ion beams are produced with GTS-LHC, a 14.5 GHz electron cyclotron resonance ion source, operated in afterglow mode. Improvement of the GTS-LHC beam formation and beam transport along Linac3 is part of the upgrade program of the injector chain in preparation for the future high luminosity LHC. A mismatch between the ion beam properties in the ion source extraction region and the acceptance of the following Low Energy Beam Transport (LEBT) section has been identified as one of the factors limiting the Linac3 performance. The installation of a new focusing element, an einzel lens, into the GTS-LHC extraction region is foreseen as a part of the Linac3 upgrade, as well as a redesign of the first section of the LEBT. Details of the upgrade and results of a beam dynamics study of the extraction region and LEBT modifications will be presented. PMID:26932084

  5. Upgrade of the beam extraction system of the GTS-LHC electron cyclotron resonance ion source at CERN

    Science.gov (United States)

    Toivanen, V.; Bellodi, G.; Dimov, V.; Küchler, D.; Lombardi, A. M.; Maintrot, M.

    2016-02-01

    Linac3 is the first accelerator in the heavy ion injector chain of the Large Hadron Collider (LHC), providing multiply charged heavy ion beams for the CERN experimental program. The ion beams are produced with GTS-LHC, a 14.5 GHz electron cyclotron resonance ion source, operated in afterglow mode. Improvement of the GTS-LHC beam formation and beam transport along Linac3 is part of the upgrade program of the injector chain in preparation for the future high luminosity LHC. A mismatch between the ion beam properties in the ion source extraction region and the acceptance of the following Low Energy Beam Transport (LEBT) section has been identified as one of the factors limiting the Linac3 performance. The installation of a new focusing element, an einzel lens, into the GTS-LHC extraction region is foreseen as a part of the Linac3 upgrade, as well as a redesign of the first section of the LEBT. Details of the upgrade and results of a beam dynamics study of the extraction region and LEBT modifications will be presented.

  6. Upgrade of the beam extraction system of the GTS-LHC electron cyclotron resonance ion source at CERN.

    Science.gov (United States)

    Toivanen, V; Bellodi, G; Dimov, V; Küchler, D; Lombardi, A M; Maintrot, M

    2016-02-01

    Linac3 is the first accelerator in the heavy ion injector chain of the Large Hadron Collider (LHC), providing multiply charged heavy ion beams for the CERN experimental program. The ion beams are produced with GTS-LHC, a 14.5 GHz electron cyclotron resonance ion source, operated in afterglow mode. Improvement of the GTS-LHC beam formation and beam transport along Linac3 is part of the upgrade program of the injector chain in preparation for the future high luminosity LHC. A mismatch between the ion beam properties in the ion source extraction region and the acceptance of the following Low Energy Beam Transport (LEBT) section has been identified as one of the factors limiting the Linac3 performance. The installation of a new focusing element, an einzel lens, into the GTS-LHC extraction region is foreseen as a part of the Linac3 upgrade, as well as a redesign of the first section of the LEBT. Details of the upgrade and results of a beam dynamics study of the extraction region and LEBT modifications will be presented.

  7. Optical vortex beam generator at nanoscale level.

    Science.gov (United States)

    Garoli, Denis; Zilio, Pierfrancesco; Gorodetski, Yuri; Tantussi, Francesco; De Angelis, Francesco

    2016-01-01

    Optical beams carrying orbital angular momentum (OAM) can find tremendous applications in several fields. In order to apply these particular beams in photonic integrated devices innovative optical elements have been proposed. Here we are interested in the generation of OAM-carrying beams at the nanoscale level. We design and experimentally demonstrate a plasmonic optical vortex emitter, based on a metal-insulator-metal holey plasmonic vortex lens. Our plasmonic element is shown to convert impinging circularly polarized light to an orbital angular momentum state capable of propagating to the far-field. Moreover, the emerging OAM can be externally adjusted by switching the handedness of the incident light polarization. The device has a radius of few micrometers and the OAM beam is generated from subwavelength aperture. The fabrication of integrated arrays of PVLs and the possible simultaneous emission of multiple optical vortices provide an easy way to the large-scale integration of optical vortex emitters for wide-ranging applications. PMID:27404659

  8. Optical vortex beam generator at nanoscale level

    Science.gov (United States)

    Garoli, Denis; Zilio, Pierfrancesco; Gorodetski, Yuri; Tantussi, Francesco; De Angelis, Francesco

    2016-01-01

    Optical beams carrying orbital angular momentum (OAM) can find tremendous applications in several fields. In order to apply these particular beams in photonic integrated devices innovative optical elements have been proposed. Here we are interested in the generation of OAM-carrying beams at the nanoscale level. We design and experimentally demonstrate a plasmonic optical vortex emitter, based on a metal-insulator-metal holey plasmonic vortex lens. Our plasmonic element is shown to convert impinging circularly polarized light to an orbital angular momentum state capable of propagating to the far-field. Moreover, the emerging OAM can be externally adjusted by switching the handedness of the incident light polarization. The device has a radius of few micrometers and the OAM beam is generated from subwavelength aperture. The fabrication of integrated arrays of PVLs and the possible simultaneous emission of multiple optical vortices provide an easy way to the large-scale integration of optical vortex emitters for wide-ranging applications. PMID:27404659

  9. Integrated multi vector vortex beam generator

    CERN Document Server

    Schulz, Sebastian A; Karimi, Ebrahim; Boyd, Robert W

    2013-01-01

    A novel method to generate and manipulate vector vortex beams in an integrated, ring resonator based geometry is proposed. We show numerically that a ring resonator, with an appropriate grating, addressed by a vertically displaced access waveguide emits a complex optical field. The emitted beam possesses a specific polarization topology, and consequently a transverse intensity profile and orbital angular momentum. We propose a combination of several concentric ring resonators, addressed with different bus guides, to generate arbitrary orbital angular momentum qudit states, which could potentially be used for classical and quantum communications. Finally, we demonstrate numerically that this device works as an orbital angular momentum sorter with an average cross-talk of -10 dB between different orbital angular momentum channels.

  10. Structured Beam Generation with a Single Metasurface

    CERN Document Server

    Yue, Fuyong; Xin, Jingtao; Gerardot, Brian; Li, Jensen; Chen, Xianzhong

    2016-01-01

    Despite a plethora of applications ranging from quantum memories to high-resolution lithography, the current technologies to generate vector vortex beams (VVBs) suffer from less efficient energy use, poor resolution, low damage threshold, bulky size and complicated experimental setup, preventing further practical applications. We propose and experimentally demonstrate an approach to generate VVBs with a single metasurface by locally tailoring phase and transverse polarization distribution. This method features the spin-orbit coupling and the superposition of the converted part with an additional phase pickup and the residual part without a phase change. By maintaining the equal components for the converted part and the residual part, the cylindrically polarized vortex beams carrying orbital angular momentum are experimentally demonstrated based on a single metasurface at subwavelength scale. The proposed approach provides unprecedented freedom in engineering the properties of optical waves with the high-effic...

  11. Experimental generation of amplitude squeezed vector beams

    CERN Document Server

    Chille, Vanessa; Semmler, Marion; Banzer, Peter; Aiello, Andrea; Leuchs, Gerd; Marquardt, Christoph

    2016-01-01

    We present an experimental method for the generation of amplitude squeezed high-order vector beams. The light is modified twice by a spatial light modulator such that the vector beam is created by means of a collinear interferometric technique. A major advantage of this approach is that it avoids systematic losses, which are detrimental as they cause decoherence in continuous-variable quantum systems. The utilisation of a spatial light modulator (SLM) gives the flexibility to switch between arbitrary mode orders. The conversion efficiency with our setup is only limited by the efficiency of the SLM. We show the experimental generation of Laguerre-Gauss (LG) modes with radial indices up to 1 and azimuthal indices up to 3 with complex polarization structures and a quantum noise reduction up to -0.9dB$\\pm$0.1dB. The corresponding polarization structures are studied in detail by measuring the spatial distribution of the Stokes parameters.

  12. Reply to the SPSC questions on Addendum CERN-SPSC-2015-038 entitled ''Beam momentum scan with Pb+Pb collisions'' by NA61/SHINE at the CERN SPS

    CERN Document Server

    Aduszkiewicz, A

    2016-01-01

    This document presents answers of the NA61/SHINE Collaborations to the SPSC questions on the addendum CERN-SPSC-2015-038; SPSC-P-330-ADD-8 (referred to as ''Addendum'') to the NA61/SHINE proposal. Addendum requests an extension of the NA61/SHINE measurements by a beam momentum scan with Pb+Pb collisions.

  13. Design and Installation Challenges of the Neutral Beam Absorbers for the Large Hadron Collider at CERN

    OpenAIRE

    Fernández Vélez, Óscar

    2005-01-01

    El CERN (Consejo Europeo de Investigación Nuclear) está construyendo su nuevo acelerador de partículas en la frontera franco-suiza. Actualmente en la fase de instalación, El Large Hadron Collider (LHC), con 26,7 kilómetros de longitud a 100 metros bajo tierra, será el mayor y más potente acelerador de partículas jamás construido. A su llegada al CERN, cada uno de casi 2000 imanes superconductores que formarán parte del acelerador debe ser verificado, ensamblado y transportado hasta ...

  14. Proton beam generation of oblique whistler waves

    Science.gov (United States)

    Wong, H. K.; Goldstein, M. L.

    1988-01-01

    It is known that ion beams are capable of generating whistler waves that propagate parallel to the mean magnetic field. Such waves may have been observed both upstream of the earth's bow shock and in the vicinity of comets. Previous analyses are extended to include propagation oblique to the mean magnetic field. The instability is generated by the perpendicular component of free energy in the ions, which can arise either via a temperature anisotropy or via a gyrating distribution. In the former case, the generation of whistler waves is confined to a fairly narrow cone of propagation directions centered about parallel propagation; in the latter case, the maximum growth of the instability can occur at fairly large obliquities (theta equal to about 50 deg).

  15. Transverse beam splitting made operational: Recent progress of the multi-turn extraction at the CERN proton synchrotron

    CERN Document Server

    AUTHOR|(CDS)2082016; Borburgh, Jan; Damjanovic, Sanja; Gilardoni, Simone; Giovannozzi, Massimo; Hourican, Michael; Kahle, Karsten; Michels, Olivier; Sterbini, Guido; Hernalsteens, Cedric; Le Godec, Gilles

    2016-01-01

    Following a successful commissioning period, the Multi-Turn Extraction (MTE) at the CERN Proton Synchrotron (PS) has been applied for the fixed-target physics programme at the Super Proton Synchrotron (SPS) since September 2015. This exceptional extraction technique was proposed to replace the long-serving Continuous Transfer (CT) extraction, which has the drawback of inducing high activation in the ring. MTE exploits the principles of non-linear beam dynamics to perform loss-free beam splitting in the horizontal phase space. Over multiple turns, the resulting beamlets are then transferred to the downstream accelerator. The operational deployment of MTE was rendered possible by the full understanding and mitigation of different hardware limitations and by redesigning the extraction trajectories and non-linear optics, which was required due to the installation of a dummy septum to reduce the activation of the magnetic extraction septum. The results of the related experimental and simulation studies, a summary ...

  16. Calculation of abort thresholds for the Beam Loss Monitoring System of the Large Hadron Collider at CERN

    CERN Document Server

    Nemcic, Martin; Dehning, Bernd

    The Beam Loss Monitoring (BLM) System is one of the most critical machine protection systems for the Large Hadron Collider (LHC) at the European Organization for Nuclear Research (CERN), Switzerland. Its main purpose is to protect the superconducting magnets from quenches and other equipment from damage by requesting a beam abort when the measured losses exceed any of the predefined threshold levels. The system consist of circa 4000 ionization chambers which are installed around the 27 kilometres ring (LHC). This study aims to choose a technical platform and produce a system that addresses all of the limitations with the current system that is used for the calculation of the LHC BLM abort threshold values. To achieve this, a comparison and benchmarking of the Java and .NET technical platforms is performed in order to establish the most suitable solution. To establish which technical platform is a successful replacement of the current abort threshold calculator, comparable prototype systems in Java and .NET we...

  17. Early steps towards quarks and their interactions using neutrino beams in CERN bubble chamber experiments

    Science.gov (United States)

    Perkins, Don H.

    2016-06-01

    Results from neutrino experiments at CERN in the1970's, using bubble chamber detectors filled with heavy liquids, gave early evidence for the existence of quarks and gluons as real dynamical objects. In detail, the measured moments of the non-singlet structure functions provided crucial support for the validity of the present theory of the strong inter-quark interactions, quantum chromodynamics.

  18. The Proton Beams for the New Time-of-Flight Neutron Facility at the CERN-PS

    CERN Document Server

    Cappi, R; Métral, G

    2000-01-01

    The experimental determination of neutron cross sections in fission and capture reactions as a function of the neutron energy is of primary importance in nuclear physics. Recent developments at CERN and elsewhere have shown that many fields of research and development, such as the design of Accelerator-Driven Systems (ADS) for nuclear waste incineration, nuclear astrophysics, fundamental nuclear physics, dosimetry for radiological protection and therapy, would benefit from a better knowledge of neutron cross sections. A neutron facility at the CERN-PS has been proposed with the aim of carrying out a systematic and high resolution study of neutron cross sections through Time-Of-Flight (n-TOF) measurement. The facility requires a high intensity proton beam (about 0.7x1013 particles/bunch) distributed in a short bunch (about 25 ns total length) to produce the neutrons by means of a spallation process in a lead target. To achieve these characteristics, a number of complex beam gymnastics have to be performed. All...

  19. LHCb: Beam and Background Monitoring and the Development of an Online Condition Analysis Tool for the LHCb Experiment at CERN

    CERN Document Server

    Alessio, F

    2010-01-01

    The LHCb experiment has been taking data since more than half a year at the LHC, recording events from collisions at the highest energy ever achieved. For its physics purposes in the sector of CP violation, the experiment will record data with the best precision achievable. An online and offline beam and background monitoring became therefore essential to understand the performance of the LHC accelerator at CERN, to monitor and study the behavior of the background around the LHCb experiment and to optimize the experimental conditions. During my second year as a Doctoral Student at CERN, I have been working on the timing and readout control as well as on the online Beam, Background, and Luminosity Monitoring of the LHCb experiment in the frame of the LHCb Online group. The group is responsible for the complete data acquisition of the LHCb experiment, from the Front-End Electronics (FEE) to the storage of the data for offline analysis, including the Timing and Fast Control (TFC) system. The latter controls and...

  20. Design and implementation of a Client-Server System for Acquiring Beam Intensity Data from High Energy Accelerators at CERN

    CERN Document Server

    Topaloudis, A; Bellas, N; Jensen, L

    The world’s largest research center in the domain of High Energy Physics (HEP) is the European Organization for Nuclear Research (CERN) whose main goal is to accelerate particles through a sequence of accelerators – accelerator complex – and bring them into collision in order to study the fundamental elements of matter and the forces acting between them. For controlling the accelerator complex, CERN needs several diagnostic tools to provide information about the beam’s attributes and one such system is the Fast Beam Current Transformer (FBCT) measuring system that provides bunch-by-bunch and total beam intensity information. The current hardware and firmware of the FBCT system has certain issues and lacks diagnostics as a lot of the calculations are done in an FPGA. In order to improve on this, the firmware was redesigned and simplified in order to increase its capabilities and provide the base of a unified FBCT measuring system that could be installed in several of CERN’s accelerator complex’s pa...

  1. Laser based stripping system for measurement of the transverse emittance of H-beams at the CERN Linac4

    CERN Document Server

    Hofmann, T; Raich, U; Roncarolo, F; Cheymol, B

    2013-01-01

    The new LINAC4 at CERN will accelerate H- particles to 160 MeV and allow high brightness proton beam transfers to the Proton Synchrotron Booster, via a charge-exchange injection scheme. This paper describes the conceptual design of a laser system proposed for transverse profile and emittance measurements based on photon detachment of electrons from the H- ions. The binding energy of the outer electron is only 0.75 eV and can easily be stripped with a laser beam. Measuring the electron signal as function of the laser position allows the transverse beam profile to be reconstructed. A downstream dipole can also be used to separate the laser neutralized H0 atoms from the main H- beam. By imaging these H0 atoms as a function of laser position the transverse emittance can be reconstructed in the same way as in traditional slit-and-grid systems. By properly dimensioning the laser power and spot size, this method results in negligible beam losses and is therefore non-destructive. In addition, the absence of material ...

  2. Silicon detectors for the neutron flux and beam profile measurements of the n_TOF facility at CERN

    Science.gov (United States)

    Musumarra, Agatino; Cosentino, Luigi; Barbagallo, Massimo; Colonna, Nicola; Damone, Lucia; Pappalardo, Alfio; Piscopo, Massimo; Finocchiaro, Paolo

    2016-09-01

    The demand of new and high precision cross section data for neutron-induced reactions is continuously growing, driven by the requirements from several fields of fundamental physics, as well as from nuclear technology, medicine, etc. Several neutron facilities are operational worldwide, and new ones are being built. In the coming years, neutron beam intensities never reached up to now will be available, thus opening new scientific and technological frontiers. Among existing facilities, n_TOF at CERN provides a high intensity pulsed neutron beam in a wide energy range (thermal to GeV) and with an extremely competitive energy resolution that also allows spectroscopy studies. In order to ensure high quality measurements, the neutron beams must be fully characterized as a function of the neutron energy, in particular by measuring the neutron flux and the beam transverse profile with high accuracy. In 2014 a new experimental area (EAR2), with a much higher neutron flux, has been completed and commissioned at n_TOF. In order to characterize the neutron beam in the newly built experimental area at n_TOF, two suitable diagnostics devices have been built by the INFN-LNS group. Both are based on silicon detectors coupled with 6Li converter foils, in particular Single Pad for the flux measurement and Position Sensitive (strips and others) for the beam profile. The devices have been completely characterized with radioactive sources and with the n_TOF neutron beam, fulfilling all the specifications and hence becoming immediately operational. The performances of these devices and their high versatility, in terms of neutron beam intensity, make them suitable to be used in both n_TOF experimental areas. A description of the devices and the main results obtained so far will be presented.

  3. Objective specific beam generation for image guided robotic radiosurgery

    Energy Technology Data Exchange (ETDEWEB)

    Schlaefer, A.; Jungmann, O.; Schweikard, A. [Inst. for Robotics and Cognitive Systems, Univ. of Luebeck (Germany); Kilby, W. [Accuray Inc., Sunnyvale, CA (United States)

    2007-06-15

    Robotic radiosurgery enables precise dose delivery throughout the body. Planning for robotic radiosurgery comprises of finding a suitable set of beams and beam weights. The problem can be addressed by generating a large set of candidate beams, and selection of beams with nonzero weight by mathematical programming. We propose to use different randomized beam generation methods depending on the type of lesion and the clinical objective. Results for three patient cases indicate that this can improve the plan quality. (orig.)

  4. Study of the pulse power supply unit for the four-horn system of the CERN to Fréjus neutrino super beam

    CERN Document Server

    Baussan, E; Dracos, M; Gaudiot, G; Osswald, F; Poussot, P; Vassilopoulos, N; Wurtz, J; Zeter, V

    2013-01-01

    The power supply studies for the four-horn system for the CERN to Fréjus neutrino Super Beam oscillation experiment are discussed here. The power supply is being studied to meet the physics potential and the mega-watt (MW) power requirements of the proton driver of the Super Beam. A one-half sinusoid current waveform with a 350 kA maximum current and pulse length of 100 \\mu s at 50 Hz frequency is generated and distributed to four-horns. In order to provide the necessary current needed to focus the charged mesons producing the neutrino beam, a bench of capacitors is charged at 50 Hz frequency to a +12 kV reference voltage and then discharged through a large switch to each horn via a set of strip-lines at the same rate. A current recovery stage allows to invert rapidly the negative voltage of the capacitor after the discharging stage in order to recuperate large part of the injected energy and thus to limit the power consuption. The energy recovery efficiency of that system is very high at 97%. For feasibilit...

  5. The Large Hadron Collider and the Super Proton Synchrotron at CERN as Tools to Generate Warm Dense Matter and Non–Ideal Plasmas

    CERN Document Server

    Tahir, N A; Shutov, A; Lomonosov, I V; Gryaznov, V; Piriz, A R; Deutsch, C; Fortov, V E

    2011-01-01

    The largest accelerator in the world, the Large Hadron Collider (LHC) at CERN, has entered into commission- ing phase. It is expected that when this impressive machine will become fully operational, it will generate two counter rotating 7 TeV/c proton beams that will be made to collide, leading to an unprecedented luminosity of 1034 cm−2s−1. Total energy stored in each LHC beam is about 362 MJ, sufficient to melt 500 kg copper. Safety of operation is a very critical issue when working with such extremely powerful beams. It is important to know the consequences of an accidental release of the beam energy in order to design protection system for the equipment. For this purpose we have carried out extensive numerical simulations of the interaction of one full LHC beam with copper and graphite targets which are materials of practical importance. Our calculations have shown that the LHC protons will penetrate up to about 35 m in solid copper and 10 m in solid graphite. A very interesting outcome of this work i...

  6. The Large Hadron Collider and the Super Proton Synchrotron at CERN as Tools to Generate Warm Dense Matter and Non-Ideal Plasmas

    CERN Document Server

    Tahir, N A; Deutsch, C; Gryaznov, V; Lomonosov, I V; Shutov, A; Piriz, A R; Fortov, V E; Geissel, H; Redmer, R

    2011-01-01

    The largest accelerator in the world, the Large Hadron Collider (LHC) at CERN, has entered into commissioning phase. It is expected that when this impressive machine will become fully operational, it will generate two counter rotating 7 TeV/c proton beams that will be made to collide, leading to an unprecedented luminosity of 10(34) cm(-2)s(-1). Total energy stored in each LHC beam is about 362 MJ, sufficient to melt 500 kg copper. Safety of operation is a very critical issue when working with such extremely powerful beams. It is important to know the consequences of an accidental release of the beam energy in order to design protection system for the equipment. For this purpose we have carried out extensive numerical simulations of the interaction of one full LHC beam with copper and graphite targets which are materials of practical importance. Our calculations have shown that the LHC protons will penetrate up to about 35 m in solid copper and 10 m in solid graphite. A very interesting outcome of this work i...

  7. Optical generation of non-diffracting beams via photorefractive holography

    CERN Document Server

    Vieira, Tarcio A; Gesualdi, Marcos R R; Zamboni-Rached, Michel

    2015-01-01

    This work presents, for the first time the optical generation of non-diffracting beams via photorefractive holography. Optical generation of non-diffracting beams using conventional optics components is difficult and, in some instances, unfeasible, as it is wave fields given by superposition of non-diffracting beams. It is known that computer generated holograms and spatial light modulators (SLMs) successfully generate such beams. With photorefractive holography technique, the hologram of a non-diffracting beam is constructed (recorded) and reconstructed (reading) optically in a nonlinear photorefractive medium. The experimental realization of a non-diffracting beam was made in a photorefractive holography setup using a photorefractive Bi12SiO20 (BSO) crystal as the holographic recording medium, where the non-diffracting beams, the Bessel beam arrays and superposition of co-propagating Bessel beams (Frozen Waves) were obtained experimentally. The experimental results are in agreement with the theoretically pr...

  8. Evidence for a New State of Matter: An Assessment of the Results from the CERN Lead Beam Programme

    OpenAIRE

    Heinz, Ulrich; Jacob, Maurice

    2000-01-01

    This "position paper" collects the scientific arguments behind the CERN Press Release of February 10, 2000, which announced evidence for the creation of a new state of matter in Pb-Pb collisions at the CERN SPS. The data on which this paper is based were presented in a special seminar at CERN on the same day, a recording of which can be accessed at http://www.cern.ch/CERN/Announcements/2000/NewStateMatter/ .

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

    CERN Document Server

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

    2016-01-01

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

  10. Space Charge Studies with High Intensity Single Bunch Beams in the CERN SPS

    CERN Document Server

    Bartosik, Hannes; Schmidt, Frank; Titze, Malte

    2016-01-01

    In order to reach the target beam parameters of the LHC injectors upgrade (LIU) project the beam degradation due to losses and emittance growth on the long injection plateau of the SPS needs to be minimized. A detailed study of the dependence of losses, transverse emittance blow-up and transverse beam tail creation as function of the working point is presented here for a high brightness single bunch beam with a vertical space charge tune spread of about 0.2 on the 26 GeV injection plateau. The beam behaviour close to important betatron resonances is characterised and a region in the tune diagram with minimal beam degradation is identified. Implications about the performance for LIU beams are discussed.

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

    CERN Document Server

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

    2015-01-01

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

  12. Calibration of LHCf calorimeters for photon measurement by CERN SPS test beam

    CERN Document Server

    Mase, T; Bonechi, L; Bongi, M; Castellini, G; D'Alessandro, R; Fukui, K; Haguenauer, M; Itow, Y; Kasahara, K; Macina, D; Masuda, K; Menjo, H; Mitsuka, G; Mizuishi, M; Muraki, Y; Nakai, M; Papini, P; Perrot, A-L; Ricciarini, S; Sako, T; Shimizu, Y; Sumi, T; Taki, K; Tamura, T; Torii, S; Tricomi, A; Turner,W C; Viciani, A; Watanabe, H; Yoshida, K

    2012-01-01

    Energy resolution and linearity of the LHCf calorimeters for electromagnetic showers were measured at the SPS H4 beam line in 2007 using electron beams of 50–200 GeV and muon beams of 150 GeV. The absolute energy scale was determined in these data. The results that were obtained (<5% energy resolution) are well understood by using Monte Carlo simulations and are good enough for the requirements of the LHCf experiment.

  13. Calibration of LHCf calorimeters for photon measurement by CERN SPS test beam

    Energy Technology Data Exchange (ETDEWEB)

    Mase, T., E-mail: mase@stelab.nagoya-u.ac.jp [Solar-Terrestrial Environment Laboratory, Nagoya University, Nagoya (Japan); Adriani, O. [INFN Section of Florence (Italy); University of Florence (Italy); Bonechi, L.; Bongi, M. [INFN Section of Florence (Italy); Castellini, G.; D' Alessandro, R. [INFN Section of Florence (Italy); University of Florence (Italy); Fukui, K. [Solar-Terrestrial Environment Laboratory, Nagoya University, Nagoya (Japan); Centro Siciliano di Fisica Nucleare e Struttura della Materia, Catania (Italy); Haguenauer, M. [Ecole-Polytechnique, Palaiseau (France); Itow, Y. [Solar-Terrestrial Environment Laboratory, Nagoya University, Nagoya (Japan); Kobayashi-Maskawa Institute for the Origin of Particles and the Universe, Nagoya University, Nagoya (Japan); Kasahara, K. [RISE, Waseda University (Japan); Macina, D. [CERN (Switzerland); Masuda, K. [Solar-Terrestrial Environment Laboratory, Nagoya University, Nagoya (Japan); Menjo, H. [INFN Section of Florence (Italy); Kobayashi-Maskawa Institute for the Origin of Particles and the Universe, Nagoya University, Nagoya (Japan); Mitsuka, G. [Solar-Terrestrial Environment Laboratory, Nagoya University, Nagoya (Japan); Mizuishi, M. [RISE, Waseda University (Japan); Muraki, Y. [Konan University (Japan); Nakai, M. [RISE, Waseda University (Japan); Papini, P. [INFN Section of Florence (Italy); Perrot, A.-L. [CERN (Switzerland); Ricciarini, S. [INFN Section of Florence (Italy); and others

    2012-04-11

    Energy resolution and linearity of the LHCf calorimeters for electromagnetic showers were measured at the SPS H4 beam line in 2007 using electron beams of 50-200 GeV and muon beams of 150 GeV. The absolute energy scale was determined in these data. The results that were obtained (<5% energy resolution) are well understood by using Monte Carlo simulations and are good enough for the requirements of the LHCf experiment.

  14. A low energy optimization of the CERN-NGS neutrino beam for a $\\theta_{13}$ driven neutrino oscillation search

    CERN Document Server

    Rubbia, André

    2002-01-01

    The possibility to improve the CERN to Gran Sasso neutrino beam performances for $\\theta_{13}$ searches is investigated. We show that by an appropriate optimization of the target and focusing optics of the present CNGS design, we can increase the flux of low energy neutrinos by about a factor 5 compared to the current $\\tau$ optimized focalisation. With the ICARUS 2.35 kton detector at LNGS and in case of negative result, this would allow to improve the limit to $\\sin^22\\theta_{13}$ by an order of magnitude better than the current limit of CHOOZ at $\\Delta m^2\\approx 3\\times 10^{-3} \\rm eV^2$ within 5 years of nominal CNGS running. This is by far the most sensitive setup of the currently approved long-baseline experiments and is competitive with the proposed JHF superbeam.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2006-02-09

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

  16. Simulation of Electron-Beam Generating Plasma at Atmospheric Pressure

    Institute of Scientific and Technical Information of China (English)

    OUYANG Liang; LI Hong; LI Benben; ZHOU Junqing; YAN Hong; SU Tie; WANG Huihui; LIUWandong

    2007-01-01

    As electron-beam generating plasma is widely applied,the software tool EGS4(Electron-Gamma Shower) was used to simulate the transmission and energy deposition of electron-beam in air.The simulation results indicated that the range of the electron-beam was inversely proportional to the gas pressure in a wide range of gas pressure,and the electron-beam of 200 keV could generate a plasma with a density 1011 cm-3 in air of latm.In addition,the energy distribution of the beam-electron and plasma density profile produced by the beam were achieved.

  17. Beam Propagation Factor and Generation of Cosh-squared-Gaussian Beams

    Institute of Scientific and Technical Information of China (English)

    ZHU Kaicheng; TANG Huiqin; ZHU Zhenhe

    2001-01-01

    A new light beam termed as a cosh-squared-Gaussian beam (ChSGB) which may be one of solutions of the paraxial wave equation for propagation in complex optical systems has been introduced. Their beam propagation factor (M2-factor) is derived and schemes to generate this light beams are proposed.

  18. Photos from MPI: Module installation at CERN for 1999 Test Beam

    CERN Multimedia

    1999-01-01

    Photo1 - Three HEC-1 modules after mating in the clean room. Photo2 - Close-up of three HEC-1 modules in the clean room when mounting the PSB boards. Photo3 - Three HEC-2 modules being inserted into the test-beam cryostat. Photo4 - Three HEC-2 modules in the test-beam cryostat. Photo5 - Three HEC-1 and three HEC-2 modules in the test-beam cryostat. Photo6 - Three HEC-1 and three HEC-2 modules in the test-beam cryostat.

  19. Interaction of the CERN Large Hadron Collider (LHC) Beam with Carbon Collimators

    CERN Document Server

    Schmidt, R; Hoffmann, Dieter H H; Kadi, Y; Shutov, A; Piriz, AR

    2006-01-01

    The LHC will operate at an energy of 7 TeV with a luminosity of 1034cm-2s-1. This requires two beams, each with 2808 bunches. The energy stored in each beam of 362 MJ. In a previous paper the mechanisms causing equipment damage in case of a failure of the machine protection system was discussed, assuming that the entire beam is deflected into a copper target [1, 2]. Another failure scenario is the deflection of beam into carbon material. Carbon collimators and beam absorbers are installed in many locations around the LHC to diffuse or absorb beam losses. Since the collimator jaws are close to the beam, it is very likely that they are hit first when the beam is accidentally deflected. Here we present the results of two-dimensional hydrodynamic simulations of the heating of a solid carbon cylinder irradiated by the LHC beam with nominal parameters, carried out using the BIG-2 computer code [3] while the energy loss of the 7 TeV protons in carbon is calculated using the well known FLUKA code [4]. Our calculation...

  20. The large hadron collider and the super proton synchrotron at CERN as tools to generate warm dense matter and non-ideal plasmas

    International Nuclear Information System (INIS)

    The largest accelerator in the world, the Large Hadron Collider (LHC) at CERN, has entered into commissioning phase. It is expected that when this impressive machine will become fully operational, it will generate two counter rotating 7 TeV/c proton beams that will be made to collide, leading to an unprecedented luminosity of 1034 cm-2s-1. Total energy stored in each LHC beam is about 362 MJ, sufficient to melt 500 kg copper. Safety of operation is a very critical issue when working with such extremely powerful beams. It is important to know the consequences of an accidental release of the beam energy in order to design protection system for the equipment. For this purpose we have carried out extensive numerical simulations of the interaction of one full LHC beam with copper and graphite targets which are materials of practical importance. Our calculations have shown that the LHC protons will penetrate up to about 35 m in solid copper and 10 m in solid graphite. A very interesting outcome of this work is that the impact of the LHC beam on solid matter will generate Warm Dense Matter (WDM) and Strongly Coupled Plasmas (SCP). The beams for the LHC are pre-accelerated in the SPS (Super Proton Synchrotron) to 450 GeV/c and transferred to LHC via two beam lines. Several SPS cycles are required to fill the LHC, in one cycle a batch with up to 288 bunches can be accelerated. From the safety point of view it is also very important to study the damage caused to the equipment in case of an accident involving an uncontrolled release of the SPS beam. For this purpose we have also carried out detailed numerical simulations of the impact of the full SPS beam on solid copper and tungsten targets. These simulations have shown that the targets are severely damaged by the beam. It is also interesting to note that also in this case, a large part of the target material is converted into WDM and SCP. This study, therefore, shows that the LHC and the SPS have the potential to be used

  1. Generation of warm dense matter and strongly coupled plasmas using the High Radiation on Materials facility at the CERN Super Proton Synchrotron

    CERN Document Server

    Tahir, N A; Brugger, M; Assmann, R; Shutov, A; Lomonosov, I V; Gryaznov, V; Piriz, A R; Udrea, S; Hoffmann, D H H; Fortov, V E; Deutsch, C

    2009-01-01

    A dedicated facility named High Radiation on Materials (HiRadMat) is being constructed at CERN to study the interaction of the 450 GeV protons generated by the Super Proton Synchrotron (SPS) with fixed solid targets of different materials. The main purpose of these future experiments is to study the generation and propagation of thermal shock waves in the target in order to assess the damage caused to the equipment, including collimators and absorbers, in case of an accident involving an uncontrolled release of the entire beam at a given point. Detailed numerical simulations of the beam-target interaction of several cases of interest have been carried out. In this paper we present simulations of the thermodynamic and the hydrodynamic response of a solid tungsten cylindrical target that is facially irradiated with the SPS beam with nominal parameters. These calculations have been carried out in two steps. First, the energy loss of the protons is calculated in the solid target using the FLUKA code (Fasso et al....

  2. Robust Collimation Control of Laser-Generated Ion Beam

    CERN Document Server

    Kawata, S; Kamiyama, D; Nagashima, T; Barada, D; Gu, Y J; Li, X; Yu, Q; Kong, Q; Wang, P X

    2015-01-01

    The robustness of a structured collimation device is discussed for an intense-laser-produced ion beam. In this paper the ion beam collimation is realized by the solid structured collimation device, which produces the transverse electric field; the electric field contributes to reduce the ion beam transverse velocity and collimate the ion beam. Our 2.5 dimensional particle-in cell simulations demonstrate that the collimation device is rather robust against the changes in the laser parameters and the collimation target sizes. The intense short-pulse lasers are now available, and are used to generate an ion beam. The issues in the laser ion acceleration include an ion beam collimation, ion energy spectrum control, ion production efficiency, ion energy control, ion beam bunching, etc. The laser-produced ion beam tends to expand in the transverse and longitudinal directions during the ion beam propagation. The ion beam collimation is focused in this paper.

  3. Validation of the Read Out Electronics for the CMS Muon Drift Chambers at Tests Beam in CERN/GIF; Validacion en el Test Beam del CERN/GIF de la electronica de Lectura de las Camaras de Muones del Experimento CMS

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez, C.; Fouz, M. c.; Marin, J.; Oller, J. C.; Willmott, C.; Amigo, L. J.

    2002-07-01

    Part of the readout system for the CMS muon drift chambers has been tested in test beams at CERN/GIF. Read Out Board (ROB) and HPTD have been validated with signals from a real muon beam, with an structure and flux similar to LHC operating conditions and using one of the chambers produced in CIEMAT already located in the test beam area under normal gas and voltage conditions. (Author) 5 refs.

  4. Influence of the transverse beam sizes on the ep -> ep. gamma. cross section at the HERA and a FUTURE CERN electron-proton collider

    Energy Technology Data Exchange (ETDEWEB)

    Kotkin, G.L.; Polityko, S.I.; Serbo, V.G.; Schiller, A.

    1988-06-01

    In the process ep -> ep..gamma.., proposed for luminosity measurements at HERA, impact parameters occur which are larger than the transverse beam sizes in the ep-colliders in HERA and a CERN option (LHC+LEP). This decreases the number of observed photons compared to the standard QED calculation. The difference is larger than 10% at photon energies E/sub ..gamma../ < 0.4E/sub e/ for the CERN option and E/sub ..gamma../ < 0.01E/sub e/ for HERA. (orig.)

  5. The Beam and Detector for the NA48 Neutral Kaon CP Violation Experiment at CERN

    CERN Document Server

    Fanti, V; Marras, D; Musa, L; Nappi, A; Batley, J Richard; Bevan, A; Dosanjh, R S; Galik, R; Gershon, T; Hay, B; Kalmus, George Ernest; Katvars, S; Lazzeroni, C; Moore, R; Munday, D J; Needham, M D; Olaiya, E; Parker, M A; Patel, M; Slater, M; Takach, S; White, T O; Wotton; Bal, F; Barr, G; Bocquet, G; Bremer, J; Brodier-Yourstone, P; Buchholz, P; Burns, M; Ceccucci, A; Clément, M; Cuhadar-Donzelsmann, T; Cundy, Donald C; Doble, Niels; Falaleev, V; Formenti, F; Funk, W; Gatignon, L; Gonidec, A; Grafström, P; Hallgren, B; Kapusta, P; Kesseler, G; Kubischta, Werner; Iwanski, W; Lacourt, A; Laverriere, G; Linser, G; Ljuslin, C; Marchioro, A; Mast, M; Matheys, J P; Morel, M; Norton, A; Orlic, J P; Panzer-Steindel, B; Schinzel, D; Seidl, W; Taureg, H; Tarlé, J C; Velasco, M; Vossnack, O; Wahl, H; Wertelaers, P; Weterings, J; Cheshkov, C; Gaponenko, A; Goudzovski, E; Khristov, P Z; Kalinin, A; Kekelidze, V D; Kozhevnikov, Yu; Madigozhin, D T; Molokanova, N A; Potrebenikov, Yu K; Tkatchev, A; Zinchenko, A I; Boyle, O; Knowles, I; Martin, V; Parsons, H; Peach, K J; Sacco, R; Veitch, E; Walker, A; Carassiti, V; Contalbrigo, M; Cotta-Ramusino, A; Dalpiaz, P; Damiani, C; Duclos, J; Ferretti, P; Frabetti, P L; Gianoli, A; Martini, M; Petrucci, F; Porcu, M; Rossi, F; Savrié, M; Scarpa, M; Simani, C; Bizzeti, A; Calvetti, M; Collazuol, G; Graziani, G; Iacopini, E; Lenti, M; Martelli, F; Michetti, A; Ruggiero, G; Veltri, M; Becker, H G; Behler, M; Blümer, H; Coward, D; Ebersberger, C; Eppard, K; Eppard, M; Fox, H; Geib, K H; Hirstius, A; Kalter, A; Kleinknecht, K; Koch, U; Köpke, L; Lopes da Silva, P; Luitz, S; Marouelli, P; Masetti, L; Melzer-Pellmann, I; Moosbrugger, U; Morales-Morales, C; Peters, A; Renk, B; Scheidt, J; Schmidt, J; Schmidt, S A; Schönharting, V; Schué, Yu; Staeck, J; Wanke, R; Wilhelm, R; Winhart, A; Wittgen, M; Zeitnitz, O; Dabrowski, A; Fonseca-Martin, T; Chollet, J C; Crépé, S; de La Taille, C; Fayard, L; Iconomidou-Fayard, L; Martin-Chassard, G; Ocariz, J; Unal, G; Wingerter-Seez, I; Anzivino, Giuseppina; Bordacchini, F; Cenci, P; Imbergamo, E; Lariccia, P; Lubrano, P; Mestvirishvili, A; Papi, A; Pepé, M; Piccini, M; Punturo, M; Talamonti, C; Tondini, F; Bertanza, L; Calafiura, P; Carosi, R; Casali, R; Cerri, C; Cirilli, M; Costantini, F; Fantechi, R; Fidecaro, Francesco; Fiorini, L; Giudici, S; Gorini, B; Laico, F; Lamanna, G; Mannelli, I; Marzulli, V; Passuello, D; Pierazzini, G M; Raffaelli, F; Sozzi, M; Tripiccione, R; Anvar, S; Bédérède, D; Bugeon, F; Chèze, J B; Cogan, J; De Beer, M; Debu, P; Durand, D; Edard, S; Fallou, J L; Formica, A; Gosset, L; Granier de Cassagnac, R; Heitzmann, J; Le Provost, H; Louis, F; Mandzhavidze, I; Mazzucato, E; Migliori, A; Mur, M; Peyaud, B; Schanne, S; Steinkamp, O; Tarte, Gérard; Turlay, René; Vallage, B; Holder, M; Augustin, I; Bender, M; Maier, A; Schwarz, I; Ziolkowski, M; Arcidiacono, R; Barberis, P L; Benotto, F; Bertolino, F; Biino, C; Brunasso, O; Cartiglia, N; Clemencic, M; Dattola, D; Goy-Lopez, S; Govi, G; Guida, R; Marchetto, F; Menichetti, E; Palestini, S; Pastrone, N; Chlopik, A; Guzik, Z; Nassalski, J P; Rondio, E; Szleper, M; Wislicki, W; Wronka, S; Dibon, Heinz; Fischer, G; Jeitler, Manfred; Markytan, Manfred; Mikulec, I; Neuhofer, G; Pernicka, M; Taurok, Anton; Widhalm, L

    2007-01-01

    The Beam and Detector, used for the NA48 experiment, devoted to the measurement of $Re(\\epsilon^{\\prime}/\\epsilon)$, and for the NA48/1 experiment on rare K_S and neutral hyperon decays, are described.

  6. Simulation and optimization of beam losses during continuous transfer extraction at the CERN Proton Synchrotron

    CERN Document Server

    Garcia, J B

    2011-01-01

    The proton beams used for the fixed target physics at the Super Proton Synchrotron (SPS) are extracted from the Proton Synchrotron ( PS) by a multiturn technique called continuous transfer (CT). During the CT extraction, large losses are observed in locations where the machine aperture should be large enough to accommodate the circulating beam. This limits the maximum intensity deliverable due to the induced stray radiation outside the PS tunnel. Scattered particles from the interaction with the electrostatic septum are identified as the possible source of these losses. This article presents a detailed study aiming to understand the origin of losses and propose possible cures. The simulations could reproduce accurately the beam loss pattern measured in real machine operation and determine the beam shaving, intrinsic to the extraction process, as the cause for the unexpected losses. Since these losses are unavoidable, the proposed solution implies a new optics scheme displacing the losses to a region with bett...

  7. Efficient Generation of Truncated Bessel Beams using Cylindrical Waveguides

    Science.gov (United States)

    Ilchenko, Vladimir S.; Mohageg, Makan; Savchenkov, Anatoliy A.; Matsko, Andrey B.; Maleki, Lute

    2007-01-01

    In this paper we address efficient conversion between a Gaussian beam (a truncated plane wave) and a truncated Bessel beam of agiven order, using cylindrical optical waveguides and whispering gallery mode resonators. Utilizing a generator based on waveguides combined with whispering gallery mode resonators, we have realized Bessel beams of the order of 200 with a conversion efficiency exceeding 10 %.

  8. Generation of the Stigmatic Beam with Orbital Angular Momentum

    Institute of Scientific and Technical Information of China (English)

    高春清; 魏光辉; Horst WEBER

    2001-01-01

    The stigmatic beam with orbital angular momentum is generated by transforming the Hermite-Gaussian beamof a diode-pumped Nd:YAG laser through a rotated cylindrical optical system. Behind the transformation optics,the output beam has an intensity distribution of ring shape and a twist phase. The beam transformation istheoretically calculated and the result has been confirmed in the experiments.

  9. Intense relativistic electron beam: generation and propagation

    International Nuclear Information System (INIS)

    A general review of relativistic electron beam extracted from explosive field emission diode has been presented here. The beam current in the diode gap taking into account cathode and anode plasma expansion velocity and excluding the self magnetic field effect is directly proportional to gap voltage V3/2 and inversely proportional to the square of the effective diode gap (d-vt). In the limit of high current, self magnetic field focusing effect comes into play and results in a critical current at which pinching will take place. When the diode current exceeds the critical current, the electron flow is in the para-potential regime. Different diode geometries such as planner, coaxial, rod-pinched, reflex triode are discussed qualitatively. When the beam is injected into a vacuum drift tube the propagation of the beam is only possible in presence of a strong axial magnetic field which prevents the beam expansion in the radial direction. If the beam is injected in the drift tube filled with dense plasma, then the redistribution of the plasma electrons effectively neutralizes the beam space charge, resulting subsequent propagation of the beam along the drift tube. The beam propagation through neutral gas is similar to the plasma filled drift tube. In this case both the neutral gas pressure and the beam current regulate the transmission of the REB. (author)

  10. Generation and application of bessel beams in electron microscopy.

    Science.gov (United States)

    Grillo, Vincenzo; Harris, Jérémie; Gazzadi, Gian Carlo; Balboni, Roberto; Mafakheri, Erfan; Dennis, Mark R; Frabboni, Stefano; Boyd, Robert W; Karimi, Ebrahim

    2016-07-01

    We report a systematic treatment of the holographic generation of electron Bessel beams, with a view to applications in electron microscopy. We describe in detail the theory underlying hologram patterning, as well as the actual electron-optical configuration used experimentally. We show that by optimizing our nanofabrication recipe, electron Bessel beams can be generated with relative efficiencies reaching 37±3%. We also demonstrate by tuning various hologram parameters that electron Bessel beams can be produced with many visible rings, making them ideal for interferometric applications, or in more highly localized forms with fewer rings, more suitable for imaging. We describe the settings required to tune beam localization in this way, and explore beam and hologram configurations that allow the convergences and topological charges of electron Bessel beams to be controlled. We also characterize the phase structure of the Bessel beams generated with our technique, using a simulation procedure that accounts for imperfections in the hologram manufacturing process. PMID:27203186

  11. Measurement of the mean radial position of a lead ion beam in the CERN PS

    CERN Document Server

    Belleman, J; González, J; Johnston, S; Schulte, E C; Thivent, E

    1996-01-01

    The intensity of the lead ion beam in the PS, nominally 4×108 charges of Pb53+ per bunch, is too low for the closed orbit measurement system. However, for successful acceleration it is sufficient to know the mean radial position (MRP). A system was thus designed for simultaneous acquisition of revolution frequency and magnetic field. The frequency measurement uses a direct digital synthesiser (DDS), phase-locked to the beam signal from a special high-sensitivity pick-up. The magnetic field is obtained from the so-called B-train. From these two values, the MRP is calculated. The precision depends on the frequency measurement and on the accuracy of the value for the magnetic field. Furthermore, exact knowledge of the transition energy is essential. This paper describes the hardware and software developed for the MRP system, and discusses the issue of calibration, with a proton beam, of the B measurement.

  12. Beam dynamics aspects of crab cavities in the CERN Large Hadron Collider

    CERN Document Server

    Sun, Y P; Barranco, J; Tomás, R; Weiler, T; Zimmermann, F; Calaga, R; Morita, A

    2009-01-01

    Modern colliders bring into collision a large number of bunches to achieve a high luminosity. The long-range beam-beam effects arising from parasitic encounters at such colliders are mitigated by introducing a crossing angle. Under these conditions, crab cavities (CC) can be used to restore effective head-on collisions and thereby to increase the geometric luminosity. Such crab cavities have been proposed for both linear and circular colliders. The crab cavities are rf cavities operated in a transverse dipole mode, which imparts on the beam particles a transverse kick that varies with the longitudinal position along the bunch. The use of crab cavities in the Large Hadron Collider (LHC) may not only raise the luminosity, but it could also complicate the beam dynamics, e.g., crab cavities might not only cancel synchrobetatron resonances excited by the crossing angle but they could also excite new ones, they could reduce the dynamic aperture for off-momentum particles, they could influence the aperture and orbit...

  13. WILL I AM visits CERN

    CERN Multimedia

    Noemi Caraban

    2013-01-01

    Will.i.am visited CERN in December 2013, fulfilling a wish he made in a video-link appearance at TEDxCERN earlier that year http://tedxcern.web.cern.ch/video/choral-performance-reach-stars-william. During his visit, he was shown the Antimatter Decelerator, the underground ATLAS experiment cavern and the CERN Control Centre. He also took the opportunity to promote CERN’s beam line for schools competition.

  14. Muon flux measurement with silicon detectors in the CERN neutrino beams

    International Nuclear Information System (INIS)

    The present work mainly describes the 'Neutrino Flux Monitoring' system (NFM), which has been built for the 400-GeV Super Proton Synchrotron (SPS) neutrino beams. A treatment is given of some general subjects related to the utilization of silicon detectors and the properties of high-energy muons. Energy loss of minimal-ionizing particles, which has to be distinguished from energy deposition in the detector, is considered. Secondary radiation, also called 'spray', consisting of 'delta rays' and other cascade products, is shown to play an important role in the muon flux measurement inside a shield, especially for muons of high energy (> 100 GeV). Radiation induced damage in the detectors, which determines the long term performance, is discussed. The relation between the detector response and the real muon flux is determined. The use of NFM system for on-line beam monitoring is described. (Auth.)

  15. Necklace Beam Generation in Nonlinear Colloidal Engineered Media

    CERN Document Server

    Silahli, Salih Z; Litchinitser, Natalia M

    2015-01-01

    Modulational instability is a phenomenon that reveals itself as the exponential growth of weak perturbations in the presence of an intense pump beam propagating in a nonlinear medium. It plays a key role in such nonlinear optical processes as supercontinuum generation, light filamentation, and rogue waves. However, practical realization of these phenomena in the majority of available nonlinear media still relies on high-intensity optical beams. Here, we analytically and numerically show the possibility of necklace beam generation originating from low-intensity spatial modulational instability of vortex beams in engineered soft-matter nonlinear media.

  16. Neutron beam imaging with micromegas detectors in combination with neutron time-of-flight at the (nTOF) facility at CERN

    International Nuclear Information System (INIS)

    A bulk micromegas detector with the anode segmented in 2 orthogonal directions and equipped with a neutron/charged particle converter is employed at the neutron time-of-flight (nTOF) facility at CERN to determine the incident neutron beam profile and beam interception factor as a function of the neutron energy determined by the time of flight. Discrepancies between experimental results and simulations in the values of the beam interception factor range up to 12 % and are to be ascribed to a defect in the mesh of the bulk. Nevertheless the detector proved to be really useful for checking the alignment of the neutron beam optics of the facility. Measurements with a new pixelized bulk detector for the determination of the beam interception factor are for seen before the end of 2012

  17. A reflex electron beam discharge as a plasma source for electron beam generation

    International Nuclear Information System (INIS)

    A reflex electron beam glow discharge has been used as a plasma source for the generation of broad-area electron beams. An electron current of 120 A (12 A/cm/sup 2/) was extracted from the plasma in 10 μs pulses and accelerated to energies greater than 1 keV in the gap between two grids. The scaling of the scheme for the generation of multikiloamp high-energy beams is discussed

  18. An OpenMP Parallelisation of Real-time Processing of CERN LHC Beam Position Monitor Data

    CERN Document Server

    Renshall, H

    2012-01-01

    SUSSIX is a FORTRAN program for the post processing of turn-by-turn Beam Position Monitor (BPM) data, which computes the frequency, amplitude, and phase of tunes and resonant lines to a high degree of precision. For analysis of LHC BPM data a specific version run through a C steering code has been implemented in the CERN Control Centre to run on a server under the Linux operating system but became a real time computational bottleneck preventing truly online study of the BPM data. Timing studies showed that the independent processing of each BPMs data was a candidate for parallelization and the Open Multiprocessing (OpenMP) package with its simple insertion of compiler directives was tried. It proved to be easy to learn and use, problem free and efficient in this case reaching a factor of ten reductions in real-time over twelve cores on a dedicated server. This paper reviews the problem, shows the critical code fragments with their OpenMP directives and the results obtained.

  19. Sagnac Interferometer Based Generation of Controllable Cylindrical Vector Beams

    Directory of Open Access Journals (Sweden)

    Cristian Acevedo

    2016-01-01

    Full Text Available We report on a novel experimental geometry to generate cylindrical vector beams in a very robust manner. Continuous control of beams’ properties is obtained using an optically addressable spatial light modulator incorporated into a Sagnac interferometer. Forked computer-generated holograms allow introducing different topological charges while orthogonally polarized beams within the interferometer permit encoding the spatial distribution of polarization. We also demonstrate the generation of complex waveforms obtained by combining two orthogonal beams having both radial modulations and azimuthal dislocations.

  20. Highly efficient electron vortex beams generated by nanofabricated phase holograms

    Energy Technology Data Exchange (ETDEWEB)

    Grillo, Vincenzo, E-mail: vincenzo.grillo@nano.cnr.it [CNR-Istituto Nanoscienze, Centro S3, Via G Campi 213/a, I-41125 Modena (Italy); CNR-IMEM Parco Area delle Scienze 37/A, I-43124 Parma (Italy); Carlo Gazzadi, Gian [CNR-Istituto Nanoscienze, Centro S3, Via G Campi 213/a, I-41125 Modena (Italy); Karimi, Ebrahim [CNR-Istituto Nanoscienze, Centro S3, Via G Campi 213/a, I-41125 Modena (Italy); Department of Physics, University of Ottawa, 150 Louis Pasteur, Ottawa, Ontario K1N 6N5 (Canada); Mafakheri, Erfan [Dipartimento di Fisica Informatica e Matematica, Università di Modena e Reggio Emilia, via G Campi 213/a, I-41125 Modena (Italy); Boyd, Robert W. [Department of Physics, University of Ottawa, 150 Louis Pasteur, Ottawa, Ontario K1N 6N5 (Canada); Frabboni, Stefano [CNR-Istituto Nanoscienze, Centro S3, Via G Campi 213/a, I-41125 Modena (Italy); Dipartimento di Fisica Informatica e Matematica, Università di Modena e Reggio Emilia, via G Campi 213/a, I-41125 Modena (Italy)

    2014-01-27

    We propose an improved type of holographic-plate suitable for the shaping of electron beams. The plate is fabricated by a focused ion beam on a silicon nitride membrane and introduces a controllable phase shift to the electron wavefunction. We adopted the optimal blazed-profile design for the phase hologram, which results in the generation of highly efficient (25%) electron vortex beams. This approach paves the route towards applications in nano-scale imaging and materials science.

  1. Second-Harmonic Generation of Bessel Beams in Lossy Media

    Institute of Scientific and Technical Information of China (English)

    丁德胜; 许坚毅; 王耀俊

    2002-01-01

    We present a further analysis for the second-harmonic generation of Bessel beams in lossy media. The emphasis is put on the effect of absorption to the radial pattern of the second-harmonic beam. It is shown that within the absorption length of the second harmonic, the Bessel second-harmonic beam approaches limited diffraction in the radial direction and behaves as in the case of lossless media.

  2. Experimental generation of ring-shaped beams with random sources

    CERN Document Server

    Reddy, Salla Gangi; Prabhakar, Shashi; Singh, R P

    2013-01-01

    We have experimentally reproduced ring shaped beams from the scattered Laguerre-Gaussian and Bessel- Gaussian beams. A rotating ground glass plate is used as a scattering medium and a plano convex lens collects the scattered light to generate ring shaped beams at the Fourier plane. The experimental results are in good agreement with the theoretical results of Mei and Korotkova (Opt. Lett. 38, 91{93 (2013)).

  3. CERN: Fixed target targets

    International Nuclear Information System (INIS)

    Full text: While the immediate priority of CERN's research programme is to exploit to the full the world's largest accelerator, the LEP electron-positron collider and its concomitant LEP200 energy upgrade (January, page 1), CERN is also mindful of its long tradition of diversified research. Away from LEP and preparations for the LHC proton-proton collider to be built above LEP in the same 27-kilometre tunnel, CERN is also preparing for a new generation of heavy ion experiments using a new source, providing heavier ions (April 1992, page 8), with first physics expected next year. CERN's smallest accelerator, the LEAR Low Energy Antiproton Ring continues to cover a wide range of research topics, and saw a record number of hours of operation in 1992. The new ISOLDE on-line isotope separator was inaugurated last year (July, page 5) and physics is already underway. The remaining effort concentrates around fixed target experiments at the SPS synchrotron, which formed the main thrust of CERN's research during the late 1970s. With the SPS and LEAR now approaching middle age, their research future was extensively studied last year. Broadly, a vigorous SPS programme looks assured until at least the end of 1995. Decisions for the longer term future of the West Experimental Area of the SPS will have to take into account the heavy demand for test beams from work towards experiments at big colliders, both at CERN and elsewhere. The North Experimental Area is the scene of larger experiments with longer lead times. Several more years of LEAR exploitation are already in the pipeline, but for the longer term, the ambitious Superlear project for a superconducting ring (January 1992, page 7) did not catch on. Neutrino physics has a long tradition at CERN, and this continues with the preparations for two major projects, the Chorus and Nomad experiments (November 1991, page 7), to start next year in the West Area. Delicate neutrino oscillation effects could become

  4. The production of dense lead-ion beams for the CERN LHC

    CERN Document Server

    Bosser, Jacques; Chanel, M; MacCaferri, R; Molinari, G; Maury, S; Möhl, D; Tranquille, G

    2000-01-01

    To reach the design luminosity for lead-ions in the LHC, the present Low Energy Antiproton Ring (LEAR) has to be converted into a Low Energy Ion Ring (LEIR). Since the present ECR lead-ion source does not provide sufficient intensity, the main goal of LEIR is to act as a low-energy (4.2MeV/u) accumulator where the ion beam is stacked and cooled (with the help of an electron-cooler) to reach the required intensity and emittances. An experimental program has been carried out at LEAR in recent years in order to test the cooling and stacking process with the present electron-cooler. A variety of results have been reported at previous conferences. This paper will focus on the electron cooling aspects resulting from the afore mentioned experiments. Taking into account the experience

  5. Electron beam generation in the fore-vacuum pressure range

    CERN Document Server

    Burachevskij, Y A; Kuzemchenko, M N; Mytnikov, A V; Oks, E M

    2001-01-01

    One presents the results of investigations to generate electron beams within 0.01-0.1 Torr gas pressure range. To generate a beam one used a plasma source based on a hollow cathode discharge in combination with a plane accelerating gap. Peculiar features of electron emission and acceleration within the mentioned pressure range are associated with high probability of gas ionization in an accelerating gap and with generation of ion flow meeting electron beam. It results in reduction of discharge combustion intensification, as well as, in plasma concentration range. The developed design of an electron source enables to generate cylindrical beams with up to 1 A current and with up to 10 keV energy

  6. Pulse Shape Characterization of Silicon Diodes for HGCal with data from Beam Test at CERN

    CERN Document Server

    De Silva, Malinda

    2016-01-01

    The High Luminosity phase of the LHC (starting operation in 2025) will provide unprecedented instantaneous and integrated luminosity, with 25 ns bunch crossing intervals and up to 140 pileup events. A challenge is to provide excellent physics performance in such a harsh environment to fully exploit the HL-LHC potentialities and explore new physics frontiers. In this context, the High Granularity Calorimeter is the detector designed to provide electromagnetic and hadronic energy coverage and reconstruction in the forward direction of the upgraded CMS. In April 2016 and June 2016, a set of 36 diodes were tested in order to understand various characteristics of its performance, in order to use them in the upgraded HG Calorimeter. Here, the silicon diodes were mounted onto a test bench at CERN’s beam test area and exposed to electron showers. Data received from these diodes were acquired and analysed separately. The objective of this report is to show the variation of Time Rise, Time Over Threshold with various...

  7. Two-color beam generation based on wakefield excitation

    Science.gov (United States)

    Bettoni, S.; Prat, E.; Reiche, S.

    2016-05-01

    Several beam manipulation methods have been studied and experimentally tested to generate two-color photon beams in free electron laser facilities to accommodate the user requests. We propose to use the interaction of the beam with an oscillating longitudinal wakefield source to obtain a suitable electron beam structure. The bunch generates two subpulses with different energies and delayed in time passing through a magnetic chicane after its longitudinal phase space has been modulated by the wakefield source. According to this approach the power of the emitted radiation is not degraded compared to the monochromatic beam, and the setup in the machine is quite simple because the bunch is manipulated only in the high energy section, where it is more rigid. We present the design applied to SwissFEL. We identified the parameters and the corresponding range of tunability of the time and energy separation among the two subbunches.

  8. Proton beam generation of whistler waves in the earth's foreshock

    Science.gov (United States)

    Wong, H. K.; Goldstein, M. L.

    1987-01-01

    It is shown that proton beams, often observed upstream of the earth's bow shock and associated with the generation of low-frequency hydromagnetic fluctuations, are also capable of generating whistler waves. The waves can be excited by an instability driven by two-temperature streaming Maxwellian proton distributions which have T (perpendicular)/T(parallel) much greater than 1. It can also be excited by gyrating proton beam distributions. These distributions generate whistler waves with frequencies ranging from 10 to 100 times the proton cyclotron frequency (in the solar wind reference frame) and provide another mechanism for generating the '1-Hz' waves often seen in the earth's foreshock.

  9. Geometric Metasurface Fork Gratings for Vortex Beam Generation and Manipulation

    CERN Document Server

    Chen, Shumei; Li, Guixin; Zhang, Shuang; Cheah, Kok Wai

    2016-01-01

    In recent years, optical vortex beams possessing orbital angular momentum have caught much attention due to their potential for high capacity optical communications. This capability arises from the unbounded topological charges of orbital angular momentum (OAM) that provides infinite freedoms for encoding information. The two most common approaches for generating vortex beams are through fork diffraction gratings and spiral phase plates. While realization of conventional spiral phase plate requires complicated 3D fabrication, the emerging field of metasurfaces has provided a planar and facile solution for generating vortex beams of arbitrary orbit angular momentum. Here we realize a novel type of geometric metasurface fork grating that seamlessly combine the functionality of a metasurface phase plate for vortex beam generation, and that of a linear phase gradient metasurface for controlling the wave propagation direction. The metasurface fork grating is therefore capable of simultaneously controlling both the...

  10. Generation and transport of laser accelerated ion beams

    International Nuclear Information System (INIS)

    Currently the LIGHT- Project (Laser Ion Generation, Handling and Transport) is performed at the GSI Helmholtzzentrum fuer Schwerionenforschung GmbH Darmstadt. Within this project, intense proton beams are generated by laser acceleration, using the TNSA mechanism. After the laser acceleration the protons are transported through the beam pipe by a pulsed power solenoid. To study the transport a VORPAL 3D simulation is compared with CST simulation. A criterion as a function of beam parameters was worked out, to rate the importance of space charge. Furthermore, an exemplary comparison of the solenoid with a magnetic quadrupole-triplet was carried out. In the further course of the LIGHT-Project, it is planned to generate ion beams with higher kinetic energies, using ultra-thin targets. The acceleration processes that can appear are: RPA (Radiation Pressure Acceleration) and BOA (Break-Out Afterburner). Therefore the transport of an ion distribution will be studied, as it emerges from a RPA acceleration.

  11. Study of interactions of the 200 GeV-CERN narrow band neutrino beam in BEBC filled with Ne-H2 heavy liquid mixture

    International Nuclear Information System (INIS)

    This thesis presents results obtained by the ABCLOS collaboration (Aachen, Bonn, CERN, London, Oxford, Saclay) in the study of neutrino induced weak interactions with BEBC. The experiment is made with the CERN 200 GeV neutrino narrow-band-beam, and uses the External Muon Identifier. Both are described in the thesis. The data obtained involve 1806 ν events and 520 antiν events. The CC and NC cross sections are first calculated. The NC one being interpreted in the frame of Weinberg-Salam model. The study of nucleon structure functions shows scaling violations, allowing quantitative tests of QCD. The study of hadronic shower gives results on dileptons production, quark fragmentation with apparition of high transverse momentum particles, and π0 and rho0 and ω0 vector meson production

  12. A NEW METHOD OF GENERATION OF OPTIMUL SECTOR BEAMS

    Directory of Open Access Journals (Sweden)

    K. SRINIVASA NAIK

    2013-07-01

    Full Text Available Generation of narrow beams with asymmetric sidelobe structure is reported by Elliott. In this method Modified Taylor’s approach is used to find out aperture distributions over a given asymmetricity. These patterns are useful to compensate roll and pitch of the sea vessels from marine radars. When a target is moving very fast, it isdifficult to scan the narrow beams to follow the target speed as it requires more number of scans. In order to overcome such problems, Sector beams with asymmetric sidelobe structure are useful. Depending on sectorial width of the beam, the number of scans can be reduced. Such beams are not reported in the literature. In view of the above facts, intensive studies are carried out to optimize the sector beams with asymmetric sidelobe structure. The present method consists of the application of phase distribution obtained by Elliott to obtain amplitude distribution by using inverse Fourier transform. For a specified beam shape, sector beams of different widths are generated with different asymmetricity in side lobe structure. They are presented in u domain (Sin θ.

  13. Generation of monoenergetic ion beams with a laser accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Pfotenhauer, Sebastian M.

    2009-01-29

    A method for the generation of monoenergetic proton and ion beams from a laser-based particle accelerator is presented. This method utilizes the unique space-charge effects occurring during relativistic laser-plasma interactions on solid targets in combination with a dot-like particle source. Due to this unique interaction geometry, MeV proton beams with an intrinsically narrow energy spectrum were obtained, for the first time, from a micrometer-scale laser accelerator. Over the past three years, the acceleration scheme has been consistently improved to enhance both the maximum particle energy and the reliability of the setup. The achieved degree of reliability allowed to derive the first scaling laws specifically for monoenergetic proton beams. Furthermore, the acceleration scheme was expanded on other target materials, enabling the generation of monoenergetic carbon beams. The experimental work was strongly supported by the parallel development of a complex theoretical model, which fully accounts for the observations and is in excellent agreement with numerical simulations. The presented results have an extraordinarily broad scope way beyond the current thesis: The availability of monoenergetic ion beams from a compact laser-plasma beam source - in conjunction with the unique properties of laser-produced particle beams - addresses a number of outstanding applications in fundamental research, material science and medical physics, and will help to shape a new generation of accelerators. (orig.)

  14. Generation of monoenergetic ion beams with a laser accelerator

    International Nuclear Information System (INIS)

    A method for the generation of monoenergetic proton and ion beams from a laser-based particle accelerator is presented. This method utilizes the unique space-charge effects occurring during relativistic laser-plasma interactions on solid targets in combination with a dot-like particle source. Due to this unique interaction geometry, MeV proton beams with an intrinsically narrow energy spectrum were obtained, for the first time, from a micrometer-scale laser accelerator. Over the past three years, the acceleration scheme has been consistently improved to enhance both the maximum particle energy and the reliability of the setup. The achieved degree of reliability allowed to derive the first scaling laws specifically for monoenergetic proton beams. Furthermore, the acceleration scheme was expanded on other target materials, enabling the generation of monoenergetic carbon beams. The experimental work was strongly supported by the parallel development of a complex theoretical model, which fully accounts for the observations and is in excellent agreement with numerical simulations. The presented results have an extraordinarily broad scope way beyond the current thesis: The availability of monoenergetic ion beams from a compact laser-plasma beam source - in conjunction with the unique properties of laser-produced particle beams - addresses a number of outstanding applications in fundamental research, material science and medical physics, and will help to shape a new generation of accelerators. (orig.)

  15. Study on nanosecond pulsed electron beam generation

    Science.gov (United States)

    Ponomarev, D.; Kholodnaya, G.; Remnev, G.; Kaikanov, M.; Sazonov, R.

    2014-11-01

    The paper presents the findings of an investigation on volt-ampere characteristics of the diode with explosive emission cathodes of different constructions (blade metal-dielectric (MD-cathode) and solid graphite cathodes) under the change of the anode-cathode gap in wide ranges. The investigations were carried out using the TEA-500 pulsed electron accelerator. The total current of the electron beam was measured using the Faraday cup (FC). A 0.5-mm foiled glass fiber laminate was used as an emitting edge of the cathode in the experimental study with the explosive emission blade MD-cathode. Based on the obtained results, the conclusion was made that the graphite cathode has the most effective efficiency factor.

  16. Study on nanosecond pulsed electron beam generation

    International Nuclear Information System (INIS)

    The paper presents the findings of an investigation on volt-ampere characteristics of the diode with explosive emission cathodes of different constructions (blade metal-dielectric (MD-cathode) and solid graphite cathodes) under the change of the anode-cathode gap in wide ranges. The investigations were carried out using the TEA-500 pulsed electron accelerator. The total current of the electron beam was measured using the Faraday cup (FC). A 0.5-mm foiled glass fiber laminate was used as an emitting edge of the cathode in the experimental study with the explosive emission blade MD-cathode. Based on the obtained results, the conclusion was made that the graphite cathode has the most effective efficiency factor

  17. The CERN PS multi-turn extraction based on beam splittting in stable islands of transverse phase space Design Report

    CERN Document Server

    Barnes, M J; Berrig, O E; Beuret, A; Borburgh, J; Bourquin, P; Brown, R; Burnet, Jean Paul; Caspers, Friedhelm; Cravero, J M; Dobers, T; Fowler, T; Gilardoni, S S; Hourican, M; Kalbreier, Willi; Kroyer, T; Di Maio, F; Martini, M; Mertens, V; Métral, E; Metzmacher, K D; Rossi, C; Royer, J P; Sermeus, L; Steerenberg, R; Villiger, G; Zickler, T

    2006-01-01

    Since 2001 considerable effort has been devoted to the study of a possible replacement of the continuous-transfer extraction mode from the PS to the SPS. Such an approach, called Multi-Turn Extraction (MTE), is based on capture of the beam inside stable islands of transverse phase space, generated by sextupoles and octupoles, thanks to a properly chosen tune variation. Both numerical simulations and measurements with beam were performed to understand the properties of this new extraction mode. The experimental study was completed at the end of 2004 and by the end of 2005 a scheme to implement this novel approach in the PS machine was defined and its performance assessed. This design report presents the outcome of the studies undertaken both in terms of technical issues as well as of resources necessary to implement the proposed scheme.

  18. Microstrip Antenna Generates Circularly Polarized Beam

    Science.gov (United States)

    Huang, J.

    1986-01-01

    Circular microstrip antenna excited with higher order transverse magnetic (TM) modes generates circularly polarized, conical radiation patterns. Found both theoretically and experimentally that peak direction of radiation pattern is varied within wide angular range by combination of mode selection and loading substrate with materials of different dielectric constants.

  19. Speckles generated by skewed, short-coherence light beams

    CERN Document Server

    Brogioli, D; Croccolo, F; Ziano, R; Mantegazza, F

    2011-01-01

    When a coherent laser beam impinges on a random sample (e.g. a colloidal suspension), the scattered light exhibits characteristic speckles. If the temporal coherence of the light source is too short, then the speckles disappear, along with the possibility of performing homodyne or heterodyne scattering detection or photon correlation spectroscopy. Here we investigate the scattering of a so-called "skewed coherence beam", i.e., a short-coherence beam modified such that the field is coherent within slabs that are skewed with respect to the wave fronts. We show that such a beam generates speckles and can be used for heterodyne scattering detection, despite its short temporal coherence. When applied to quite turbid samples, the technique has the remarkable advantage of suppressing the multiple scattering contribution of the scattering signal. The phenomenon presented here represents a very effective method for measuring the coherence skewness of either a continuous wave or a pulsed beam. Another field of applicat...

  20. Slow electrostatic fluctuations generated by beam-plasma interaction

    CERN Document Server

    Pommois, Karen; Pezzi, Oreste; Veltri, Pierluigi

    2016-01-01

    Eulerian simulations of the Vlasov-Poisson equations have been employed to analyze the excitation of slow electrostatic fluctuations (with phase speed close to the electron thermal speed), due to a beam-plasma interaction, and their propagation in linear and nonlinear regime. In 1968, O'Neil and Malmberg [Phys. Fluids {\\bf 11}, 1754 (1968)] dubbed these waves "beam modes". In the present paper, it is shown that, in the presence of a cold and low density electron beam, these beam modes can become unstable and then survive Landau damping unlike the Langmuir waves. When an electron beam is launched in a plasma of Maxwellian electrons and motionless protons and this initial equilibrium is perturbed by a monochromatic density disturbance, the electric field amplitude grows exponentially in time and then undergoes nonlinear saturation, associated with the kinetic effects of particle trapping and phase space vortex generation. Moreover, if the initial density perturbation is setup in the form of a low amplitude rand...

  1. Necklace beam generation in nonlinear colloidal engineered media.

    Science.gov (United States)

    Silahli, Salih Z; Walasik, Wiktor; Litchinitser, Natalia M

    2015-12-15

    Modulational instability is a phenomenon that reveals itself as the exponential growth of weak perturbations in the presence of an intense pump beam propagating in a nonlinear medium. It plays a key role in such nonlinear optical processes as supercontinuum generation, light filamentation, rogue waves, and ring (or necklace) beam formation. To date, a majority of studies of these phenomena have focused on light-matter interactions in self-focusing Kerr media existing in nature. However, a large and tunable nonlinear response of a colloidal suspension can be tailored at will by judiciously engineering the optical polarizability. Here, we analytically and numerically show the possibility of necklace beam generation originating from spatial modulational instability of vortex beams in engineered soft-matter nonlinear media with different types of exponential nonlinearity. PMID:26670494

  2. Nonlinear generation of whistler waves by an ion beam

    Science.gov (United States)

    Akimoto, K.; Winske, D.

    1989-01-01

    An electromagnetic hybrid code is used to simulate a new mechanism for whistler wave generation by an ion beam. First, a field-aligned ion beam becomes unstable to the electromagnetic ion/ion right-hand resonant instability which generates large amplitude MHD-like waves. These waves then trap the ion beam and increase its effective temperature anisotropy. As a result, the growth rates of the electron/whistler instability are significantly enhanced, and whistlers start to grow above the noise level. At the same time, because of the reduced parallel drift speed of the ion beam, the frequencies of the whistlers are also downshifted. Full simulations were performed to isolate and separately investigate the electron/ion whistler instability. The results are in agreement with the assumption of fluid electrons in the hybrid simulations and with the linear theory of the instability.

  3. Geometric Metasurface Fork Gratings for Vortex Beam Generation and Manipulation

    OpenAIRE

    Chen, Shumei; Cai, Yuan; Li, Guixin; Shuang ZHANG; Cheah, Kok Wai

    2016-01-01

    In recent years, optical vortex beams possessing orbital angular momentum have caught much attention due to their potential for high capacity optical communications. This capability arises from the unbounded topological charges of orbital angular momentum (OAM) that provides infinite freedoms for encoding information. The two most common approaches for generating vortex beams are through fork diffraction gratings and spiral phase plates. While realization of conventional spiral phase plate re...

  4. Electron Beam Collimation for the Next Generation Light Source

    Energy Technology Data Exchange (ETDEWEB)

    Steier, C.; Emma, P.; Nishimura, H.; Papadopoulos, C.; Sannibale, F.

    2013-05-20

    The Next Generation Light Source will deliver high (MHz) repetition rate electron beams to an array of free electron lasers. Because of the significant average current in such a facility, effective beam collimation is extremely important to minimize radiation damage to undulators, prevent quenches of superconducting cavities, limit dose rates outside of the accelerator tunnel and prevent equipment damage. This paper describes the early conceptual design of a collimation system, as well as initial results of simulations to test its effectiveness.

  5. Generation of compensated ion beams from source with oscillating electrons

    CERN Document Server

    Borisko, V N; Yunakov, N N

    2000-01-01

    The generation of compensated ion beams from electrically unsymmetrical reflecting discharge was investigated.The spatial location of a compensation zone,the optimal values of operating gas pressures P=(0.8/1) centre dot 10 sup - sup 4 Torr and potential difference between cathodes DELTA U = 80B were determined.The way to control the current compensation degree of the extracted ion beam a several to 100% was found.

  6. Simplified Generation of High-Angular-Momentum Light Beams

    Science.gov (United States)

    Savchenkov, Anatoliy; Maleki, Lute; Matsko, Andrey; Strekalov, Dmitry; Grudinin, Ivan

    2007-01-01

    A simplified method of generating a beam of light having a relatively high value of angular momentum (see figure) involves the use of a compact apparatus consisting mainly of a laser, a whispering- gallery-mode (WGM) resonator, and optical fibers. The method also can be used to generate a Bessel beam. ( Bessel beam denotes a member of a class of non-diffracting beams, so named because their amplitudes are proportional to Bessel functions of the radii from their central axes. High-order Bessel beams can have high values of angular momentum.) High-angular-momentum light beams are used in some applications in biology and nanotechnology, wherein they are known for their ability to apply torque to make microscopic objects rotate. High-angular-momentum light beams could also be used to increase bandwidths of fiber-optic communication systems. The present simplified method of generating a high-angular-momentum light beam was conceived as an alternative to prior such methods, which are complicated and require optical setups that include, variously, holograms, modulating Fabry-Perot cavities, or special microstructures. The present simplified method exploits a combination of the complex structure of the electromagnetic field inside a WGM resonator, total internal reflection in the WGM resonator, and the electromagnetic modes supported by an optical fiber. The optical fiber used to extract light from the WGM resonator is made of fused quartz. The output end of this fiber is polished flat and perpendicular to the fiber axis. The input end of this fiber is cut on a slant and placed very close to the WGM resonator at an appropriate position and orientation. To excite the resonant whispering- gallery modes, light is introduced into the WGM resonator via another optical fiber that is part of a pigtailed fiber-optic coupler. Light extracted from the WGM resonator is transformed into a high-angular- momentum beam inside the extraction optical fiber and this beam is emitted from the

  7. Bunch beam production and microwave generation in reditrons

    International Nuclear Information System (INIS)

    The authors have discovered in our two-dimensional particle-in-cell simulations that the oscillation of virtual cathodes in reditrons can produce a highly modulated electron beam. Full (100%) current modulation of the leakage electron beam was observed in our simulations. The modulation is at the frequency of the oscillating virtual cathode and the transverse magnetic mode generated by the reditron. The authors have further incorporated an inverse diode with a line impedance of 50 ohms in the reditron and showed that 28% of the kinetic energy of the modulated electron beam was converted into transverse electromagnetic waves with peak power of 1 GW

  8. Bunch beam production and microwave generation in reditrons

    Energy Technology Data Exchange (ETDEWEB)

    Kwan, T.J.T.; Davis, H.A.; Fulton, R.D.; Sherwood, E.G.

    1989-01-01

    We have discovered in our two-dimensional particle-in-cell simulations that the oscillation of virtual cathodes in reditrons can produce a highly modulated electron beam. Full (100%) current modulation of the leakage electron beam was observed in our simulations. The modulation is at the frequency of the oscillating virtual cathode and the transverse magnetic mode generated by the reditron. We had further incorporated an inverse diode in the reditron and showed that the kinetic energy of the modulated electron beam was efficiently converted into transverse electromagnetic waves. Our simulations showed an efficiency of 26% and the time averaged microwave power was about 6 GW. 7 refs., 8 figs.

  9. Bunch Beam Production And Microwave Generation In Reditrons

    Science.gov (United States)

    Kwan, Thomas J. T.; Davis, Harold A.; Fulton, Robert D.; Sherwood, Eugene G.

    1989-07-01

    We have discovered in our two-dimensional particle-in-cell simulations that the oscillation of virtual cathodes in reditrons can produce a highly modulated electron beam. Full (100%) current modulation of the leakage electron beam was observed in our simulations. The modulation is at the frequency of the oscillating virtual cathode and the transverse magnetic mode generated by the reditron. We had further incorporated an inverse diode with a line impedance of 50 ohms in the reditron and showed that 28% of the kinetic energy of the modulated electron beam was converted into transverse electromagnetic waves with peak power of 1 GW.

  10. Angular-momentum-dominated electron beams and flat-beam generation

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Yin-e

    2005-06-01

    In the absence of external forces, if the dynamics within an electron beam is dominated by its angular momentum rather than other effects such as random thermal motion or self Coulomb-repulsive force (i.e., space-charge force), the beam is said to be angular-momentum-dominated. Such a beam can be directly applied to the field of electron-cooling of heavy ions; or it can be manipulated into an electron beam with large transverse emittance ratio, i.e., a flat beam. A flat beam is of interest for high-energy electron-positron colliders or accelerator-based light sources. An angular-momentum-dominated beam is generated at the Fermilab/NICADD photoinjector Laboratory (FNPL) and is accelerated to an energy of 16 MeV. The properties of such a beam is investigated systematically in experiment. The experimental results are in very good agreement with analytical expectations and simulation results. This lays a good foundation for the transformation of an angular-momentum-dominated beam into a flat beam. The round-to-flat beam transformer is composed of three skew quadrupoles. Based on a good knowledge of the angular-momentum-dominated beam, the quadrupoles are set to the proper strengths in order to apply a total torque which removes the angular momentum, resulting in a flat beam. For bunch charge around 0.5 nC, an emittance ratio of 100 {+-} 5 was measured, with the smaller normalized root-mean-square emittance around 0.4 mm-mrad. Effects limiting the flat-beam emittance ratio are investigated, such as the chromatic effects in the round-to-flat beam transformer, asymmetry in the initial angular-momentum-dominated beam, and space-charge effects. The most important limiting factor turns out to be the uncorrelated emittance growth caused by space charge when the beam energy is low, for example, in the rf gun area. As a result of such emittance growth prior to the round-to-flat beam transformer, the emittance ratio achievable in simulation decreases from orders of thousands to

  11. CERN, Geneva

    CERN Multimedia

    2007-01-01

    "The Large Hadron Collider (pages 1-3) is being built at CERN, the European Centre for Nuclear Research near Geneva. CERN offers some extremely exciting opportunities to see "big bang" in action. (1 page)

  12. The sputter generation of negative ion beams

    International Nuclear Information System (INIS)

    A brief review is given of recent progress toward a quantitative understanding of negative ion formation by sputtering from surfaces covered with fractional layers of highly electropositive adsorbates. Practical models developed for estimating changes in work functions Δφ by electropositive adsorbates are described. The secondary negative ion generation process is examined through the use of composite energy/velocity dependent analytical models. These models are used to illustrate the effect of work function on the energy distributions of negative ions sputter ejected from a polycrystalline molybdenum surface covered with fractional layers of cesium. Predictions are also made of the functional dependence of the probability for negative ion formation on cesium coverage. The models predict energy distributions which are in basic disagreement with experimental observations, implying their inappropriateness for describing the sputter negative ion generation process. We have also developed a model for calculating sputter ratios based on the use of simple scaling procedures to bring Sigmund theory into close agreement with experimental observation accounting for the threshold effect. Scaling factors for projectile energies E > 1000 eV are found to be independent of energy while those for projectile energies Eth < E < 1000 eV were found to be energy dependent. In this study, the model and scaling techniques utilized to bring Sigmund theory into agreement with experiment are discussed in detail and several examples provided which illustrate the versatility, accuracy and utility of the model. In the present report, we describe the model and apply it to the case of sputtering a selected number of metals with energetic cesium ions. In particular, we present sputter ratio information for a number of Cs-projectile/metal-target combinations; the targets are bombarded at normal incidence to the surface

  13. Conditional eddies, or clumps, in ion-beam-generated turbulence

    DEFF Research Database (Denmark)

    Johnsen, Helene; Pecseli, H. L.; Trulsen, J.

    1985-01-01

    Low-frequency electrostatic fluctuations are investigated experimentally in an unmagnetized plasma. The turbulence is generated by ion-ion-beam instabilities. Real-time signals are recorded and investigated statistically on a conditional basis. The formation and propagation of structures with a r......Low-frequency electrostatic fluctuations are investigated experimentally in an unmagnetized plasma. The turbulence is generated by ion-ion-beam instabilities. Real-time signals are recorded and investigated statistically on a conditional basis. The formation and propagation of structures...

  14. Experimental and numerical studies on the proposed application of hollow electron beam collimation for the LHC at CERN

    CERN Document Server

    Moens, Vince; Redaelli, Stefano; Rivkin, Leonid

    This thesis work was carried out in the framework of U.S. LHC Accelerator Research Program (USLARP), a collaboration between the European Organization for Nuclear Research (CERN) and the U.S. Department of Energy. The first half of the work was completed at Fermilab (USA), the location of the Tevatron, a proton-antiproton collider and the second largest particle collider in the world. The second half was completed at CERN (Switzerland), the location of the largest proton collider in the world (Large Hadron Collider (LHC)).\

  15. Development of compact quantum beam generation system and the application

    International Nuclear Information System (INIS)

    After the approval of the project as the 'High-Tech Research Center Project' conducted by MEXT at Waseda University, the laser driven photo-cathode RF-Gun (RF-Gun) has been developed very extensively. The system was developed to obtain the stable and high quality (i.e. very low emittance) electron beam in conjunction with the system stabilization such as RF power source and laser system for the electron emission. The high quality electron beams have been applied for the development of novel beam diagnostic system. At the same time, the beams (electron and laser) are applied for the inverse Compton scattering experiment for the generation of soft-X-ray with quasi-monochromatic energy and short time structure, and for the pump probe experiment (the pico-second pulse radiolysis) as the very compact system. (author)

  16. Propagation model for vector beams generated by metasurfaces.

    Science.gov (United States)

    Shu, Weixing; Liu, Yachao; Ke, Yougang; Ling, Xiaohui; Liu, Zhenxing; Huang, Bin; Luo, Hailu; Yin, Xiaobo

    2016-09-01

    A propagation model of vector beams generated by metasurfaces based on vector diffraction theory is established theoretically and verified experimentally. Considering the Pancharatnam-Berry phase introduced by the metasurface, analytical forms of vector beams for arbitrary incident polarization and topological charge of metasurfaces are found in the Fresnel and Fraunhofer diffraction regions, respectively. The complex amplitude of the resultant vector beam can be described in terms of a confluent hypergeometric function, with an intensity profile that manifests concentric rings in the Fresnel region and a single ring in the Fraunhofer one. Fraunhofer diffraction provides a method to create vector beams with simultaneously high purity and modal power. Further experiments verify the theoretical results. PMID:27607720

  17. Modelling the spatial shape of nondiffracting beams: Experimental generation of Frozen Waves via computer generated holograms

    CERN Document Server

    Vieira, Tárcio A; Gesualdi, Marcos R R

    2013-01-01

    In this paper we implement experimentally the spatial shape modelling of nondiffracting optical beams via computer generated holograms. The results reported here are the experimental confirmation of the so called Frozen Wave method, developed few years ago. Optical beams of this type can possess potential applications in optical tweezers, medicine, atom guiding, remote sensing, etc..

  18. CERN neutrino project on target

    CERN Multimedia

    2005-01-01

    Scientists at CERN announced the completion of the target assembly for the CERN neutrinos to Gran Sasso project, CNGS. On schedule for start-up in May 2006, CNGS will send a beam of neutrinos through the Earth to the Gran Sasso laboratory 730 km away in Italy in a bid to unravel the mysteries of nature's most elusive particles (½ page)

  19. Population inversions in ablation plasmas generated by intense electron beams

    Science.gov (United States)

    Gilgenbach, R. M.; Kammash, T.; Brake, M. L.

    1988-11-01

    Experiments during the past three years have concerned the generation and spectroscopic study of electron beam-driven carbon plasmas in order to explore the production of optical and ultraviolet radiation from nonequilibrium populations. The output of MELBA (Michigan Electron Long Beam Accelerator), has been connected to an electron beam diode consisting of an aluminum (or brass) cathode stalk and a carbon anode. Magnetic field coils have been designed, procured, and utilized to focus the electron beam. A side viewing port permitted spectroscopic diagnostics to view across the surface of the anode. Spectroscopic diagnosis has been performed using a 1 m spectrograph capable of operation from the vacuum ultraviolet through the visible. This spectrograph is coupled to a 1024 channel optical multichannel analyzer. Spectra taken during the initial 400 ns period of the e-beam pulse showed a low effective charge plasma with primarily molecular components (C2, CH) as well as atomic hydrogen and singly ionized carbon (CII). When the generator pulse was crowbarred after the first 400 ns, the spectra revealed a continuation of the low charge state plasma.

  20. High power semiconductor switches in the 12 kV, 50 kA pulse generator of the SPS beam dump kicker system

    CERN Document Server

    Bonthond, J; Faure, P; Vossenberg, Eugène B

    2001-01-01

    Horizontal deflection of the beam in the dump kicker system of the CERN SPS accelerator is obtained with a series of fast pulsed magnets. The high current pulses of 50 kA per magnet are generated with capacitor discharge type generators which, combined with a resistive free-wheel diode circuit, deliver a critically damped half-sine current with a rise-time of 25 ms. Each generator consists of two 25 kA units, connected in parallel to a magnet via a low inductance transmission line.

  1. Generation of subnanosecond electron beams in air at atmospheric pressure

    Science.gov (United States)

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

    2009-11-01

    Optimum conditions for the generation of runaway electron beams with maximum current amplitudes and densities in nanosecond pulsed discharges in air at atmospheric pressure are determined. A supershort avalanche electron beam (SAEB) with a current amplitude of ˜30 A, a current density of ˜20 A/cm2, and a pulse full width at half maximum (FWHM) of ˜100 ps has been observed behind the output foil of an air-filled diode. It is shown that the position of the SAEB current maximum relative to the voltage pulse front exhibits a time shift that varies when the small-size collector is moved over the foil surface.

  2. Generation of high brightness ion beam from insulated anode PED

    International Nuclear Information System (INIS)

    Generation and focusing of a high density ion beam with high brightness from a organic center part of anode of a PED was reported previously. Mass, charge and energy distribution of this beam were analyzed. Three kind of anode were tried. Many highly ionized medium mass ions (up to C4+, O6+) accelarated to several times of voltage difference between anode and cathode were observed. In the case of all insulator anode the current carried by the medium mass ions is about half of that carried by protons. (author)

  3. Electron beam generation in high voltage glow discharges

    International Nuclear Information System (INIS)

    The generation of intense CW and pulsed electron beams in glow discharges in reviewed. Glow discharge electron guns operate at a pressure of the order of 1 Torr and often have an advantage in applications that require a broad area electron beam in a gaseous atmosphere, such as laser excitation and some aspects of materials processing. Aspects of electron gun design are covered. Diagnostics of the high voltage glow discharges including the electric field distribution mapped by Doppler free laser spectroscopy, and plasma density and electron temperature measurements of the electron yield of different cathode materials under glow discharge conditions are presented

  4. CERN achievements in relativistic heavy ion collisions

    Directory of Open Access Journals (Sweden)

    Bruno Giuseppe Eugenio

    2015-01-01

    Full Text Available Twenty years after a Letter of Intent by the GSI and LBL groups for the “Study of particle production and target fragmentation in central 20Ne on Pb reactions, at 12 GeV per nucleon energy of the CERN PS external beam" [1], based on the results found by the NA45/CERES, NA49, NA50, and WA97/NA57 experiments at the SPS, CERN announced compelling evidence for the formation of a new state of matter in heavyion collisions at CERN-SPS energies [2]. Some of the experiments were indeed the 2nd or 3rd generation successors of the apparatuses originally proposed by the GSI-LBL collaboration. Actually, the CERN ion program initiated at the SPS with the acceleration of oxygen ions at 60 and 200 GeV/nucleon only in 1986, and continued with sulphur ions at 200 GeV/nucleon up to 1993. The rest is history: lead-ion beams at 160 GeV/nucleon became available at the SPS in 1994; the LHC accelerated and collided lead beams at a center of mass energy per nucleon pair √sNN = 2.76 TeV in 2010. Heavy ion physics is definitely in the future program of CERN: ALICE will operate a major upgrade of its detectors during the second long shutdown of the LHC, in 2018-2019, and the associated physics program will span the third and fourth LHC runs, till late 2020s.

  5. A method for generating double-ring-shaped vector beams

    Science.gov (United States)

    Huan, Chen; Xiao-Hui, Ling; Zhi-Hong, Chen; Qian-Guang, Li; Hao, Lv; Hua-Qing, Yu; Xu-Nong, Yi

    2016-07-01

    We propose a method for generating double-ring-shaped vector beams. A step phase introduced by a spatial light modulator (SLM) first makes the incident laser beam have a nodal cycle. This phase is dynamic in nature because it depends on the optical length. Then a Pancharatnam–Berry phase (PBP) optical element is used to manipulate the local polarization of the optical field by modulating the geometric phase. The experimental results show that this scheme can effectively create double-ring-shaped vector beams. It provides much greater flexibility to manipulate the phase and polarization by simultaneously modulating the dynamic and the geometric phases. Project supported by the National Natural Science Foundation of China (Grant No. 11547017), the Hubei Engineering University Research Foundation, China (Grant No. z2014001), and the Natural Science Foundation of Hubei Province, China (Grant No. 2014CFB578).

  6. Higher harmonics generation in relativistic electron beam with virtual cathode

    Energy Technology Data Exchange (ETDEWEB)

    Kurkin, S. A., E-mail: KurkinSA@gmail.com; Badarin, A. A.; Koronovskii, A. A.; Hramov, A. E. [Saratov State Technical University, Politechnicheskaja 77, Saratov 410028, Russia and Saratov State University, Astrakhanskaja 83, Saratov 410012 (Russian Federation)

    2014-09-15

    The study of the microwave generation regimes with intense higher harmonics taking place in a high-power vircator consisting of a relativistic electron beam with a virtual cathode has been made. The characteristics of these regimes, in particular, the typical spectra and their variations with the change of the system parameters (beam current, the induction of external magnetic field) as well as physical processes occurring in the system have been analyzed by means of 3D electromagnetic simulation. It has been shown that the system under study demonstrates the tendency to the sufficient growth of the amplitudes of higher harmonics in the spectrum of current oscillations in the VC region with the increase of beam current. The obtained results allow us to consider virtual cathode oscillators as promising high power mmw-to-THz sources.

  7. Higher harmonics generation in relativistic electron beam with virtual cathode

    Science.gov (United States)

    Kurkin, S. A.; Badarin, A. A.; Koronovskii, A. A.; Hramov, A. E.

    2014-09-01

    The study of the microwave generation regimes with intense higher harmonics taking place in a high-power vircator consisting of a relativistic electron beam with a virtual cathode has been made. The characteristics of these regimes, in particular, the typical spectra and their variations with the change of the system parameters (beam current, the induction of external magnetic field) as well as physical processes occurring in the system have been analyzed by means of 3D electromagnetic simulation. It has been shown that the system under study demonstrates the tendency to the sufficient growth of the amplitudes of higher harmonics in the spectrum of current oscillations in the VC region with the increase of beam current. The obtained results allow us to consider virtual cathode oscillators as promising high power mmw-to-THz sources.

  8. Rapid Process to Generate Beam Envelopes for Optical System Analysis

    Science.gov (United States)

    Howard, Joseph; Seals, Lenward

    2012-01-01

    The task of evaluating obstructions in the optical throughput of an optical system requires the use of two disciplines, and hence, two models: optical models for the details of optical propagation, and mechanical models for determining the actual structure that exists in the optical system. Previous analysis methods for creating beam envelopes (or cones of light) for use in this obstruction analysis were found to be cumbersome to calculate and take significant time and resources to complete. A new process was developed that takes less time to complete beam envelope analysis, is more accurate and less dependent upon manual node tracking to create the beam envelopes, and eases the burden on the mechanical CAD (computer-aided design) designers to form the beam solids. This algorithm allows rapid generation of beam envelopes for optical system obstruction analysis. Ray trace information is taken from optical design software and used to generate CAD objects that represent the boundary of the beam envelopes for detailed analysis in mechanical CAD software. Matlab is used to call ray trace data from the optical model for all fields and entrance pupil points of interest. These are chosen to be the edge of each space, so that these rays produce the bounding volume for the beam. The x and y global coordinate data is collected on the surface planes of interest, typically an image of the field and entrance pupil internal of the optical system. This x and y coordinate data is then evaluated using a convex hull algorithm, which removes any internal points, which are unnecessary to produce the bounding volume of interest. At this point, tolerances can be applied to expand the size of either the field or aperture, depending on the allocations. Once this minimum set of coordinates on the pupil and field is obtained, a new set of rays is generated between the field plane and aperture plane (or vice-versa). These rays are then evaluated at planes between the aperture and field, at a

  9. Gamma-ray generation using laser-accelerated electron beam

    Science.gov (United States)

    Park, Seong Hee; Lee, Ho-Hyung; Lee, Kitae; Cha, Yong-Ho; Lee, Ji-Young; Kim, Kyung-Nam; Jeong, Young Uk

    2011-06-01

    A compact gamma-ray source using laser-accelerated electron beam is being under development at KAERI for nuclear applications, such as, radiography, nuclear activation, photonuclear reaction, and so on. One of two different schemes, Bremsstrahlung radiation and Compton backscattering, may be selected depending on the required specification of photons and/or the energy of electron beams. Compton backscattered gamma-ray source is tunable and quasimonochromatic and requires electron beams with its energy of higher than 100 MeV to produced MeV photons. Bremsstrahlung radiation can generate high energy photons with 20 - 30 MeV electron beams, but its spectrum is continuous. As we know, laser accelerators are good for compact size due to localized shielding at the expense of low average flux, while linear RF accelerators are good for high average flux. We present the design issues for a compact gamma-ray source at KAERI, via either Bremsstrahlung radiation or Compton backscattering, using laser accelerated electron beams for the potential nuclear applications.

  10. CERN Choir

    CERN Multimedia

    Staff Association

    2015-01-01

      Do you like singing? The CERN Choir is looking for basses and tenors Join us! Programme Spring Session 2015: Donizetti: Misere & Missa di Gloria e Credo Bellini: Salve Regina Bruckner: Requiem in D minor Next concert: Sunday 31 May 2015 at 17:00 Musicales de Comesières (GE) Rehearsals at CERN Main Auditorium, building 500 On Wednesdays from 20.00 to 22:00 Membership fee: January to June 150 CHF September to December: 100CHF Contact: Baudouin.bleus@cern.ch Facebook/Choeur-du-CERN

  11. CERN SUMMER SCHOOL 2015 PROJECT REPORT

    CERN Document Server

    Jin, Zizhuo Tony

    2015-01-01

    The context of this internship is the CERN summer student program for the year 2015. As a member of the CERN summer school, I have been assigned, in addition to the classes I attended in the morning, a scientific project within the BE-ABP-HSC section. This work was done under the directions of Benoit Salvant and Nicolo Biancacci whom I thank greatly for their help, patience and teaching. The project consisted in observing the effects generated by the beam passing through various devices. We focused mainly on the electromagnetic waves generated by beams of particles travelling along two of the accelerator's devices: A wire scanner and the TDI (LHC injection beam stopper). These Simulations are of importance to estimate the effect of the beam onto the surrounding apparatus and ensuring both that the latter doesn't get damaged and that the beam doesn't lose too much energy. All the models and simulations were done using c CST STUDIO SUITE software developed by the c CST company.

  12. Rapid generation of light beams carrying orbital angular momentum.

    Science.gov (United States)

    Mirhosseini, Mohammad; Magaña-Loaiza, Omar S; Chen, Changchen; Rodenburg, Brandon; Malik, Mehul; Boyd, Robert W

    2013-12-16

    We report a technique for encoding both amplitude and phase variations onto a laser beam using a single digital micro-mirror device (DMD). Using this technique, we generate Laguerre-Gaussian and vortex orbital-angular-momentum (OAM) modes, along with modes in a set that is mutually unbiased with respect to the OAM basis. Additionally, we have demonstrated rapid switching among the generated modes at a speed of 4 kHz, which is much faster than the speed regularly achieved by phase-only spatial light modulators (SLMs). The dynamic control of both phase and amplitude of a laser beam is an enabling technology for classical communication and quantum key distribution (QKD) systems that employ spatial mode encoding.

  13. Measurement and interpretation of transverse beam instabilities in the CERN large hadron collider (LHC) and extrapolations to HL-LHC

    CERN Document Server

    AUTHOR|(CDS)2067185; Arduini, Gianluigi; Barranco Navarro, Laura; Buffat, Xavier; Carver, Lee Robert; Iadarola, Giovanni; Li, Kevin Shing Bruce; Pieloni, Tatiana; Romano, Annalisa; Rumolo, Giovanni; Salvant, Benoit; Schenk, Michael; Tambasco, Claudia; Biancacci, Nicolo

    2016-01-01

    Since the first transverse instability observed in 2010, many studies have been performed on both measurement and simulation sides and several lessons have been learned. In a machine like the LHC, not only all the mechanisms have to be understood separately, but the possible interplays between the different phenomena need to be analysed in detail, including the beam-coupling impedance (with in particular all the necessary collimators to protect the machine but also new equipment such as crab cavities for HL-LHC), linear and nonlinear chromaticity, Landau octupoles (and other intrinsic nonlinearities), transverse damper, space charge, beam-beam (long-range and head-on), electron cloud, linear coupling strength, tune separation between the transverse planes, tune split between the two beams, transverse beam separation between the two beams, etc. This paper reviews all the transverse beam instabilities observed and simulated so far, the mitigation measures which have been put in place, the remaining questions an...

  14. Analysis of 440 GeV proton beam-matter interaction experiments at the High Radiation Materials test facility at CERN

    Science.gov (United States)

    Burkart, F.; Schmidt, R.; Raginel, V.; Wollmann, D.; Tahir, N. A.; Shutov, A.; Piriz, A. R.

    2015-08-01

    In a previous paper [Schmidt et al., Phys. Plasmas 21, 080701 (2014)], we presented the first results on beam-matter interaction experiments that were carried out at the High Radiation Materials test facility at CERN. In these experiments, extended cylindrical targets of solid copper were irradiated with beam of 440 GeV protons delivered by the Super Proton Synchrotron (SPS). The beam comprised of a large number of high intensity proton bunches, each bunch having a length of 0.5 ns with a 50 ns gap between two neighboring bunches, while the length of this entire bunch train was about 7 μs. These experiments established the existence of the hydrodynamic tunneling phenomenon the first time. Detailed numerical simulations of these experiments were also carried out which were reported in detail in another paper [Tahir et al., Phys. Rev. E 90, 063112 (2014)]. Excellent agreement was found between the experimental measurements and the simulation results that validate our previous simulations done using the Large Hadron Collider (LHC) beam of 7 TeV protons [Tahir et al., Phys. Rev. Spec. Top.--Accel. Beams 15, 051003 (2012)]. According to these simulations, the range of the full LHC proton beam and the hadronic shower can be increased by more than an order of magnitude due to the hydrodynamic tunneling, compared to that of a single proton. This effect is of considerable importance for the design of machine protection system for hadron accelerators such as SPS, LHC, and Future Circular Collider. Recently, using metal cutting technology, the targets used in these experiments have been dissected into finer pieces for visual and microscopic inspection in order to establish the precise penetration depth of the protons and the corresponding hadronic shower. This, we believe will be helpful in studying the very important phenomenon of hydrodynamic tunneling in a more quantitative manner. The details of this experimental work together with a comparison with the numerical

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

    Institute of Scientific and Technical Information of China (English)

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

    2006-01-01

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

  16. Rapid Generation of Light Beams Carrying Orbital Angular Momentum

    OpenAIRE

    Mirhosseini, Mohammad; Magana-Loaiza, Omar S.; Chen, Changchen; Rodenburg, Brandon; Malik, Mehul; Boyd, Robert W

    2013-01-01

    We report a technique for encoding both amplitude and phase variations onto a laser beam using a single digital micro-mirror device (DMD). Using this technique, we generate Laguerre-Gaussian and vortex orbital-angular-momentum (OAM) modes, along with modes in a set that is mutually unbiased with respect to the OAM basis. Additionally, we have demonstrated rapid switching among the generated modes at a speed of 4 kHz, which is much faster than the speed regularly achieved by spatial light modu...

  17. Courrier CERN

    CERN Multimedia

    2015-01-01

    Example of the cover page of the French version of the CERN Courier; Courrier CERN from January 1962. The journal was published both in English and French up to volume 45, no. 5, June 2005. Since then there is a single-language edition where articles are published either in French or English with an abstract in the other language.

  18. Generation of polarization vortex beams by segmented quarter-wave plates

    Institute of Scientific and Technical Information of China (English)

    Jingtao Xin; Xiaoping Lou; Zhehai Zhou; Mingli Dong; Lianqing Zhu

    2016-01-01

    A spatially variable retardation device,an SQWP,is designed to generate polarization vortex beams.The transformation of Laguerre-Gaussian beams by the SQWP is further studied,and it is found that the SQWPs can also be used to generate helical beams and measure the topological charges of helical beams.

  19. CERN & Society

    CERN Multimedia

    2016-01-01

    Non Member State Summer Students 2015 are interviewed about their decision to study STEM subjects, to apply for CERN NMSSS programme, their experience onsite @CERN and takeaways, their future goals and aspirations, offering also advice to fellow students.The Non Member State Summer Student Programme stands for a unique opportunity for students from all over the world to spend their summer at CERN in Geneva, getting involved in some of the world’s biggest experiments. For 8 weeks, summer students gather on-site at CERN and join in the day-to-day work of research. The Programme targets advanced undergraduate and beginning graduate students of physics, computing and engineering, particularly from developing countries. Participating students receive scientific training, attend lectures and work on laboratory-based projects alongside with CERN experts and fellow students.

  20. Microwave generation and frequency conversion using intense relativistic electron beams

    International Nuclear Information System (INIS)

    Some aspects of the microwave generation and frequency conversion by relativistic electron beams are studied. Using an electron synchrotron maser, the excitation of microwaves by an annular relativistic electron beam propagating through a circular wave guide immersed in a longitudinal magnetic field is analyzed. This theoretical model is somewhat more realistic than the previous one because the guiding centers are not on the wave guide axis. Microwave reflection is observed on a R.E.B. front propagating into a gas filled waveguide. The frequency conversion from the incident X-band e.m. waves and the reflected Ka band observed signal is consistent with the Doppler model for β = 0.7. This value agrees with the average beam front velocity as measured from time-of-flight using two B/sub theta/ probes. The reflection is found to occur during the current rise time. With a low impedance device (2 Ω, 400 keV) a GW X-band emission has been observed using thin anodes and a gas filled waveguide. This emission is probably due to the self-fields of the beam and could be used as a diagnostic

  1. Radially polarized annular beam generated through a second-harmonic-generation process.

    Science.gov (United States)

    Sato, Shunichi; Kozawa, Yuichi

    2009-10-15

    A radially polarized beam with an annular intensity pattern was generated through a second-harmonic-generation process by focusing an azimuthally polarized Ti:sapphire pulsed laser beam to a c-cut beta-barium borate (BBO) crystal. The annular intensity pattern of the second-harmonic wave had a nearly sixfold symmetry as a result of the nonlinear susceptibility tensor of the BBO crystal. The width of the annulus was as narrow as less than 1/40th of its radius.

  2. Radially polarized annular beam generated through a second-harmonic-generation process.

    Science.gov (United States)

    Sato, Shunichi; Kozawa, Yuichi

    2009-10-15

    A radially polarized beam with an annular intensity pattern was generated through a second-harmonic-generation process by focusing an azimuthally polarized Ti:sapphire pulsed laser beam to a c-cut beta-barium borate (BBO) crystal. The annular intensity pattern of the second-harmonic wave had a nearly sixfold symmetry as a result of the nonlinear susceptibility tensor of the BBO crystal. The width of the annulus was as narrow as less than 1/40th of its radius. PMID:19838261

  3. Whistler wave generation by non-gyrotropic, relativistic, electron beams

    Science.gov (United States)

    Skender, Marina; Tsiklauri, David

    2014-05-01

    Super-thermal electron beams travelling away from the Sun on the open magnetic field lines are widely accepted to be the source of the Type-III bursts. The earliest idea of the generation of the Type-III bursts was based on the plasma emission mechanism. A fast moving electron beam excites Langmuir waves at the local plasma frequency, ωp. The Langmuir waves are partially transformed via scattering at ωp and 2ωp, with ion sound and oppositely propagating Langmuir waves, respectively, into electromagnetic waves. As the electron beam propagates away from the Sun, through less dense coronal and interplanetary environment, the frequency of the emitted electromagnetic radiation decreases, because plasma frequency is a function of the square root of the plasma density. Type-III bursts have been subject of theoretical, observational and numerical studies. The first detailed theory of the Type-III emission invoked coherent plasma waves, generated by a stream of fast particles, which are due to Rayleigh and combination scattering at ωp and 2ωp subsequently transformed into radio waves. Stochastic growth of the density irregularities was invoked in order to produce stochastically generated clumpy Langmuir waves, where the ambient density perturbations cause the beam to fluctuate around marginal stability. Other theories on the mechanism which generates the Type-III emission include: linear mode conversion of Langmuir waves, Langmuir waves producing electromagnetic radiation as antennas and non-gyroptropic electron beam emission [1] of commensurable properties to the Type-III bursts. In Refs. [2,3] it was found that the non-gyrotropic beam excites electromagnetic radiation by the current transverse to the magnetic field, which results in (ω,k)-space drift while propagating along the 1-dimensional spatial domain throughout the decreasing plasma density profile. The role of the electron beam pitch angle and the background density gradient profile was investigated in [4

  4. Accelerating airy beams generated by ultrafast laser induced space-variant nanostructures in glass

    OpenAIRE

    Gecevičius, M.; M. Beresna; Kazansky, P. G.

    2012-01-01

    We demonstrate new technique to generate accelerating Airy beam with femtosecond laser imprinted space variant birefringence produced by self-assembled nanostructures in fused silica. The technique enables dual Airy beam generation.

  5. Ion Beam Analysis applied to laser-generated plasmas

    Science.gov (United States)

    Cutroneo, M.; Macková, A.; Havranek, V.; Malinsky, P.; Torrisi, L.; Kormunda, M.; Barchuk, M.; Ullschmied, J.; Dudzak, R.

    2016-04-01

    This paper presents the research activity on Ion Beam Analysis methods performed at Tandetron Laboratory (LT) of the Institute of Nuclear Physics AS CR, Rez, Czech Republic. Recently, many groups are paying attention to implantation by laser generated plasma. This process allows to insert a controllable amount of energetic ions into the surface layers of different materials modifying the physical and chemical properties of the surface material. Different substrates are implanted by accelerated ions from plasma through terawatt iodine laser, at nominal intensity of 1015 W/cm2, at the PALS Research Infrastructure AS CR, in the Czech Republic. This regime of the laser matter interaction generates, multi-MeV proton beams, and multi-charged ions that are tightly confined in time (hundreds ps) and space (source radius of a few microns). These ion beams have a much lower transverse temperature, a much shorter duration and a much higher current than those obtainable from conventional accelerators. The implementation of protons and ions acceleration driven by ultra-short high intensity lasers is exhibited by adopting suitable irradiation conditions as well as tailored targets. An overview of implanted targets and their morphological and structural characterizations is presented and discussed.

  6. Ion Beam Analysis applied to laser-generated plasmas

    International Nuclear Information System (INIS)

    This paper presents the research activity on Ion Beam Analysis methods performed at Tandetron Laboratory (LT) of the Institute of Nuclear Physics AS CR, Rez, Czech Republic. Recently, many groups are paying attention to implantation by laser generated plasma. This process allows to insert a controllable amount of energetic ions into the surface layers of different materials modifying the physical and chemical properties of the surface material. Different substrates are implanted by accelerated ions from plasma through terawatt iodine laser, at nominal intensity of 1015 W/cm2, at the PALS Research Infrastructure AS CR, in the Czech Republic. This regime of the laser matter interaction generates, multi-MeV proton beams, and multi-charged ions that are tightly confined in time (hundreds ps) and space (source radius of a few microns). These ion beams have a much lower transverse temperature, a much shorter duration and a much higher current than those obtainable from conventional accelerators. The implementation of protons and ions acceleration driven by ultra-short high intensity lasers is exhibited by adopting suitable irradiation conditions as well as tailored targets. An overview of implanted targets and their morphological and structural characterizations is presented and discussed

  7. Whistler wave generation by non-gyrotropic, relativistic, electron beams

    CERN Document Server

    Skender, Marina

    2014-01-01

    Particle-in-cell code, EPOCH, is used for studying features of the wave component evident to propagate backwards from the front of the non-gyrotropic, relativistic beam of electrons injected in the Maxwellian, magnetised background plasma with decreasing density profile. According to recent findings presented in Tsiklauri (2011), Schmitz & Tsiklauri (2013) and Pechhacker & Tsiklauri (2012), in a 1.5-dimensional magnetised plasma system, the non-gyrotropic beam generates freely escaping electromagnetic radiation with properties similar to the Type-III solar radio bursts. In this study the backwards propagating wave component evident in the perpendicular components of the elecromagnetic field in such a system is presented for the first time. Background magnetic field strength in the system is varied in order to prove that the backwards propagating wave's frequency, prescribed by the whistler wave dispersion relation, is proportional to the specified magnetic field. Moreover, the identified whistlers are...

  8. Development of rf plasma generators for neutral beams

    International Nuclear Information System (INIS)

    The development of low frequency (1-2 MHz) rf plasma generators for high power neutral beam applications is summarized. Immersed couplers from one to three turns were used. Acceptable plasma profiles, less than or equal to 15% max/min, were obtained in a variety of field-free magnetic bucket and magnetic filter-bucket sources, with 10 x 10 cm or 10 x 40 cm extraction areas. Hydrogen beam properties were measured with a 7 x 10 cm accelerator operated at 80 kV. Atomic fraction and power efficiency were at least as high as with arc plasmas in similar chambers. The potential advantages of an rf plasma source are: ease of operation; reliability; and extended service lifetime

  9. Simulations of beam-matter interaction experiments at the CERN HiRadMat facility and prospects of high-energy-density physics research.

    Science.gov (United States)

    Tahir, N A; Burkart, F; Shutov, A; Schmidt, R; Wollmann, D; Piriz, A R

    2014-12-01

    In a recent publication [Schmidt et al., Phys. Plasmas 21, 080701 (2014)], we reported results on beam-target interaction experiments that have been carried out at the CERN HiRadMat (High Radiation to Materials) facility using extended solid copper cylindrical targets that were irradiated with a 440-GeV proton beam delivered by the Super Proton Synchrotron (SPS). On the one hand, these experiments confirmed the existence of hydrodynamic tunneling of the protons that leads to substantial increase in the range of the protons and the corresponding hadron shower in the target, a phenomenon predicted by our previous theoretical investigations [Tahir et al., Phys. Rev. ST Accel. Beams 25, 051003 (2012)]. On the other hand, these experiments demonstrated that the beam heated part of the target is severely damaged and is converted into different phases of high energy density (HED) matter, as suggested by our previous theoretical studies [Tahir et al., Phys. Rev. E 79, 046410 (2009)]. The latter confirms that the HiRadMat facility can be used to study HED physics. In the present paper, we give details of the numerical simulations carried out to understand the experimental measurements. These include the evolution of the physical parameters, for example, density, temperature, pressure, and the internal energy in the target, during and after the irradiation. This information is important in order to determine the region of the HED phase diagram that can be accessed in such experiments. These simulations have been done using the energy deposition code fluka and a two-dimensional hydrodynamic code, big2, iteratively.

  10. A novel diamond-based beam position monitoring system for the High Radiation to Materials facility at CERN SPS

    CERN Document Server

    AUTHOR|(CDS)2092886; Höglund, Carina

    The High Radiation to Materials facility employs a high intensity pulsed beam imposing several challenges on the beam position monitors. Diamond has been shown to be a resilient material with its radiation hardness and mechanical strength, while it is also simple due to its wide bandgap removing the need for doping. A new type of diamond based beam position monitor has been constructed, which includes a hole in the center of the diamond where the majority of the beam is intended to pass through. This increases the longevity of the detectors as well as allowing them to be used for high intensity beams. The purpose of this thesis is to evaluate the performance of the detectors in the High Radiation to Materials facility for various beam parameters, involving differences in position, size, bunch intensity and bunch number. A prestudy consisting of calibration of the detectors using single incident particles is also presented. The detectors are shown to work as intended after a recalibration of the algorithm, alb...

  11. Beam-generated upper hybrid noise in Jupiter's outer magnetosphere

    International Nuclear Information System (INIS)

    Upper hybrid waves in Jupiter's outer magnetosphere are the subject of this paper which proposes a new theoretical model for their generation. Energetic electrons are assumed to be accelerated in the high-latitude auroral zone and stream away from the planet to the outer magnetosphere. The electrons travel along magnetic field lines located at the edges of the plasma sheet through a region which has the properties of a plasma sheet boundary layer similar to the terrestrial entity. The kinematic evolution of the electron beam results in a highly collimated field-aligned distribution which excites quasi-perpendicular upper hybrid waves through a so-called beam-anisotropic heat flux instability. The instability is dominated by anomalous cyclotron harmonic resonances in a parameter regime where the gyroradius of the beam electrons is comparable to the wavelength of the wave. Propagation of the upper hybrid waves across the magnetic field into a plasma density gradient produces a spectrum of z mode waves which then undergo a linear mode conversion to ordinary mode electromagnetic radiation. The model successfully accounts for the observations of upper hybrid noise, Z mode emissions, and continuum radiation in the Jovian magnetosphere in a self-consistent coherent manner

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-07-01

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

  13. CERN Rocks

    CERN Multimedia

    2004-01-01

    The 15th CERN Hardronic Festival took place on 17 July on the terrace of Rest 3 (Prévessin). Over 1000 people, from CERN and other International Organizations, came to enjoy the warm summer night, and to watch the best of the World's High Energy music. Jazz, rock, pop, country, metal, blues, funk and punk blasted out from 9 bands from the CERN Musiclub and Jazz club, alternating on two stages in a non-stop show.  The night reached its hottest point when The Canettes Blues Band got everybody dancing to sixties R&B tunes (pictured). Meanwhile, the bars and food vans were working at full capacity, under the expert management of the CERN Softball club, who were at the same time running a Softball tournament in the adjacent "Higgs Field". The Hardronic Festival is the main yearly CERN music event, and it is organized with the support of the Staff Association and the CERN Administration.

  14. Whistler wave generation by non-gyrotropic, relativistic, electron beams

    International Nuclear Information System (INIS)

    Particle-in-cell code, EPOCH, is used for studying features of the wave component evident to propagate backwards from the front of the non-gyrotropic, relativistic beam of electrons injected in the Maxwellian, magnetised background plasma with decreasing density profile. According to recent findings presented in Tsiklauri [Phys. Plasmas 18, 052903 (2011)], Schmitz and Tsiklauri [Phys. Plasmas 20, 062903 (2013)], and Pechhacker and Tsiklauri [Phys. Plasmas 19, 112903 (2012)], in a 1.5-dimensional magnetised plasma system, the non-gyrotropic beam generates freely escaping electromagnetic radiation with properties similar to the Type-III solar radio bursts. In this study, the backwards propagating wave component evident in the perpendicular components of the electromagnetic field in such a system is presented for the first time. Background magnetic field strength in the system is varied in order to prove that the backwards propagating wave's frequency, prescribed by the whistler wave dispersion relation, is proportional to the specified magnetic field. Moreover, the identified whistlers are shown to be generated by the normal Doppler-shifted relativistic resonance. Large fraction of the energy of the perpendicular electromagnetic field components is found to be carried away by the whistler waves, while a small but sufficient fraction is going into L- and R-electromagnetic modes

  15. Status of PACMAN Project at CERN

    CERN Document Server

    Catalan-Lasheras, Nuria; Modena , Michele

    2015-01-01

    Though the Large Hadron Collider (LHC) at CERN is just at the start of a program expected to run for 20 additional years, CERN is studying the next generation of colliders, like the Compact Linear Collider (CLIC). This project proposes an electron-positron collider with a length close to 50 km and with a centre of mass energy of 3 TeV at the collision point. One of the main challenges is the sub-micrometric size of the beams, down to a few nanometres at the interaction point. As a consequence, the accelerator will require unprecedented nanometric tolerances of beam alignment. A series of several thousands components will have to be assembled, aligned at the micrometre level and most critically, stabilized actively at the nanometre level. PACMAN, a study on Particle Accelerator Components Metrology and Alignment to the Nanometre scale, is a Marie Curie Program supported by the European Commission (FP7 Program), creating a network of 16 Academic and Industrial Partners. The project is hosted at CERN and it offe...

  16. [The CERN and the megascience].

    Science.gov (United States)

    Aguilar Peris, José

    2006-01-01

    In this work we analyse the biggest particle accelerator in the world: the LHC (Large Hadron Collider). The ring shaped tunnel is 27 km long and it is buried over 110 meters underground, straddling the border betwen France and Switzerland at the CERN laboratory near Geneva. Its mission is to recreate the conditions that existed shortly after the Big-Bang and to look for the hypothesised Higgs particle. The LHC will accelerate protons near the speed of the light and collide them head on at an energy of to 14 TeV (1 TeV = 10(12) eV). Keeping such high energy in the proton beams requires enormous magnetic fields which are generated by superconducting electromagnets chilled to less than two degrees above absolute zero. It is expected that LHC will be inaugurated in summer 2007.

  17. Spatial properties of a terahertz beam generated from a two-color air plasma

    DEFF Research Database (Denmark)

    Pedersen, Pernille Klarskov; Wang, Tianwu; Buron, Jonas Christian Due;

    2013-01-01

    We present a spatial characterization of terahertz (THz) beams generated from a two-color air plasma under different conditions by measuring full 3D beam profiles using a commercial THz camera. We compare two THz beam profiles emitted from plasmas generated by 35 fs and 100 fs laser pulses...

  18. Choice of parameters for tesla transformer of pulsed power beam generator type

    International Nuclear Information System (INIS)

    The accelerating voltage pulse generators of relativistic electron beams and high-power ion beam accelerators are subdivided into two main types: Marx generators and Tesla transformer type generators.In presented paper the attempt to create the methodology of the engineering substantiation of parameters and designing the Tesla transformer type generator for pulsed power accelerators is undertaken

  19. Choice of parameters for tesla transformer of pulsed power beam generator type

    CERN Document Server

    Kolchanova, V A; Petrov, A V

    2001-01-01

    The accelerating voltage pulse generators of relativistic electron beams and high-power ion beam accelerators are subdivided into two main types: Marx generators and Tesla transformer type generators.In presented paper the attempt to create the methodology of the engineering substantiation of parameters and designing the Tesla transformer type generator for pulsed power accelerators is undertaken.

  20. A Cherenkov-based Beam Loss Scintillator system for beam, background and online luminosity monitoring at the LHCb experiment at CERN

    CERN Document Server

    Alessio, F; Jacobsson, R

    2013-01-01

    The installation of a scintillator-based system in the LHCb cavern was initially proposed in order to observe injection problems around the LHCb interaction region. Thanks to the fact that LHCb had already developed a custom-made electronics board (BPIM) for the LHCb beam pickups and global LHCb timing monitoring, a complete, inexpensive but flexible and robust system was quickly developed and installed few cm from the beam pipe just in front of the LHCb VELO detector in time for the very first beams injected in the LHC. The current and final system – commonly referred to as Beam Loss Scintillator (BLS) system - ultimately played a central role in the fast beam, background and online luminosity monitoring at LHCb. In this paper, the features of the detector – based on quartz radiator and Cherenkov light - are described, including the functionalities that the system acquired during the proton-proton physics programmes in 2009- 2013 thanks to its flexibility, reliability and sensitivity to beam hal...

  1. Development of GUIs for CERN devices

    CERN Document Server

    Ruggaard Pedersen, Mathias

    2013-01-01

    This report documents the work that was done during a summer student internship in the CERN BE-BI-SW group in the summer of 2013. The original project proposal was to produce a java GUI to simplify the setting up of a CERN beam instrument. The end result of the project is two desktop applications for monitoring two different beam instruments as well as an Android app meant as a prototype for monitoring arbitrary beam instruments on a smartphone.

  2. Reliability of the beam loss monitors system for the large hadron collider at CERN; Fiabilite du systeme des moniteurs de pertes du faisceau pour le Large Hadron Collider au CERN

    Energy Technology Data Exchange (ETDEWEB)

    Guaglio, G

    2005-12-15

    The energy stored in the Large Hadron Collider is unprecedented. The impact of the beam particles can cause severe damage on the superconductive magnets, resulting in significant downtime for repairing. The Beam Loss Monitors System (BLMS) detects the secondary particles shower of the lost beam particles and initiates the extraction of the beam before any serious damage to the equipment can occur. This thesis defines the BLMS specifications in term of reliability. The main goal is the design of a system minimizing both the probability to not detect a dangerous loss and the number of false alarms generated. The reliability theory and techniques utilized are described. The prediction of the hazard rates, the testing procedures, the Failure Modes Effects and Criticalities Analysis and the Fault Tree Analysis have been used to provide an estimation of the probability to damage a magnet, of the number of false alarms and of the number of generated warnings. The weakest components in the BLMS have been pointed out. The reliability figures of the BLMS have been calculated using a commercial software package (Isograph.). The effect of the variation of the parameters on the obtained results has been evaluated with a sensitivity analysis. The reliability model has been extended by the results of radiation tests. Design improvements, like redundant optical transmission, have been implemented in an iterative process. The proposed system is compliant with the reliability requirements. The model uncertainties are given by the limited knowledge of the thresholds levels of the superconductive magnets and of the locations of the losses along the ring. The implemented model allows modifications of the system, following the measuring of the hazard rates during the LHC life. It can also provide reference numbers to other accelerators which will implement similar technologies. (author)

  3. Generation of optical vector beams using a two-mode fiber.

    Science.gov (United States)

    Viswanathan, Nirmal K; Inavalli, V V G

    2009-04-15

    We present the generation of optical vector beams using a two-mode fiber (TMF)-based beam converter. The TMF converts the input Gaussian (TEM(00)) beam into linearly polarized Hermite-Gaussian (HG(10), HG(01)) beams, a radially polarized Laguerre-Gaussian (LG(1)(0)) beam with single helical charge or coherent linear combinations of the different vector modes guided in the fiber, depending on the input beam polarization, the fiber length, and the launch condition. Polarization and two-beam interference analyses of the output beam characterize the electric field orientations of the output beam and the presence of transverse and longitudinal optical vortex in the generated HG and LG beams. PMID:19370113

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

    CERN Document Server

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

    2016-01-01

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

  5. Efficient generation of isolated attosecond pulses with high beam-quality by two-color Bessel-Gauss beams

    CERN Document Server

    Wang, Zhe; Zhang, Qingbin; Wang, Shaoyi; Lu, Peixiang

    2011-01-01

    The generation of isolated attosecond pulses with high efficiency and high beam quality is essential for attosec- ond spectroscopy. We numerically investigate the supercontinuum generation in a neutral rare-gas medium driven by a two-color Bessel-Gauss beam. The results show that an efficient smooth supercontinuum in the plateau is obtained after propagation, and the spatial profile of the generated attosecond pulse is Gaussian-like with the divergence angle of 0.1 degree in the far field. This bright source with high beam quality is beneficial for detecting and controlling the microscopic processes on attosecond time scale.

  6. Development of radio frequency induction plasma generators for neutral beams

    International Nuclear Information System (INIS)

    The techniques, operational aspects, and experimental results of a radio frequency induction plasma generator, with an internal rf power coupler, intended for intense neutral beam applications are described. One of the development sources suitable for 10 x 10-cm2 extraction optics was operated to a deuterium ion current density of 250 mA/cm2, uniform to 5%, over a circular extraction area 15 cm in diameter with a coupled rf power of 20 kW. Temporal fluctuation levels in the extracted ion current were measured to be typically 1% of the dc level. A second developmental source suitable for 10 x 40-cm2 grid sets was operated to 200 mA/cm2, uniform to +- 8% over a 10 x 40 cm2 area, with 40-kW coupled rf power

  7. Beam steering by computer generated hologram for optical switches

    Science.gov (United States)

    Yamaguchi, Keita; Suzuki, Kenya; Yamaguchi, Joji

    2016-02-01

    We describe a computer generated hologram (CGH) method for application to a multiple input and multiple output (MxN) optical switch based on a liquid crystal on silicon (LCOS). The conventional MxN optical switch needs multiple spatial light modulations. However, the CGH method realizes an MxN optical switch simply with a one-time spatial light modulation, resulting in fewer optical elements and better cost efficiency. Moreover, the intrinsic loss of the proposed MxN switch resulting from beam splitting can be reduced by routing multiple signals with a single knob control, which is called a multi-pole multi-throw switch. In this paper, we demonstrate a 5x5 wavelength selective switch (WSS) and a 2-degree ROADM that we realized using the above CGH method. The experimental results indicate that these switches work well with a crosstalk of < -14.9 dB.

  8. CERN television news

    CERN Multimedia

    2002-01-01

    CERN events brought right to your desktop by the new video bulletin.   CERN now has its very own news broadcast , or rather 'webcast', with a host of special reports and even a star presenter. From today onwards, just go to the Bulletin's web page, click on the 'video news' link and sit back and enjoy the latest news about CERN, presented in images by Wendy Korda. The ten-minute newscast in both French and English, the Organization's two official languages, presents interviews, pictures of experiments and computer-generated graphics, bringing you right up to date with some of the Laboratory's latest stories. The show concludes with a selection of the best snapshots taken by the CERN Photo Lab. So every one or two months CERN's Audio-Video Service (ETT/DH) will be putting together a video news report that you can watch on your own desktop computer. Daniel Boileau, Patrick Gilbert de Vautibault and Jacques Fichet, the Service's three technicians, came up with the idea of producing this regular feat...

  9. Radiography at CERN

    CERN Multimedia

    HSE Unit

    2014-01-01

    What is industrial radiography? It is a non-destructive method with a wide variety of applications, such as inspecting the quality of a weld. It uses high-energy radioactive sources or an X-ray generator.   Is this inspection technique used at CERN? Yes, it is widely used at CERN by the EN-MME Group, which outsources the work to one or more companies, depending on the workload. Is it possible to carry out radiography anywhere at CERN? Yes, it is possible to carry out radiography in any building/accelerator/experiment area at CERN (including in areas which are not normally subject to radiological hazards). When is radiography carried out? It normally takes place outside of working hours (7 p.m. to 6 a.m.). How will I know if radiography is taking place in my building? If this activity is planned in a CERN building, notices will be affixed to all of its main entrance doors at least 24 hours in advance. What are the risks? There is a risk of exposure to very high levels of radiation, dep...

  10. Safety alarms at CERN

    CERN Document Server

    Ninin, P; Henny, L

    1998-01-01

    In order to operate the CERN accelerators complex safely, the acquisition, transport and management of safety alarms is of crucial importance. The French regulatory authority [Direction de Sûreté des Installations Nucléaires de Base (INB)] defines them as Level 3 alarms; they represent as such a danger for the life and require an immediate intervention of the Fire Brigade. Safety alarms are generated by fire and flammable gas detection systems, electrical emergency stops, and other safety related systems. Level 3 alarms are transmitted for reliability reasons to their operation centre: the CERN Safety Control Room (SCR) using two different media: the hard-wired network and a computer based system. The hard-wired networks are connected to local panels summarizing in 34 security areas the overall CERN geography. The computer based system offers data management facilities such as alarm acquisition, distribution, archiving and information correlation. The Level 3 alarms system is in constant evolution in order...

  11. Literature in Focus Beta Beams: Neutrino Beams

    CERN Multimedia

    2009-01-01

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

  12. Generation of Electron Bessel Beams with Nondiffractive Spreading by a Nanofabricated Annular Slit

    Science.gov (United States)

    Saitoh, Koh; Hirakawa, Kazuma; Nambu, Hiroki; Tanaka, Nobuo; Uchida, Masaya

    2016-04-01

    The shaping of a wavefront of free electrons has been experimentally realized very recently. We report the generation of an electron Bessel beam using a nanofabricated annular slit. We directly observe that electron Bessel beams propagate while maintaining a narrow beam width over a long propagation distance. In addition, we experimentally verify the self-healing property of these electron beams, which can reconstruct their shape after passing an obstacle. The experimental results are compared with simulation results of the propagation including a hexagonal slit. The present technique of electron Bessel beam generation can be used to develop a novel electron-beam-shaping, an atomic manipulation technique, and a new electron microscopy.

  13. Function generation and regulation libraries and their application to the control of the new main power converter (POPS) at the CERN CPS

    International Nuclear Information System (INIS)

    Power converter control for the LHC is based on an embedded control computer called a Function Generator/Controller (FGC). Every converter includes an FGC with responsibility for the generation of the reference current as a function of time and the regulation of the circuit current, as well as control of the converter state. With many new converter controls software classes in development it was decided to generalize several key components of the FGC software in the form of C libraries: function generation in libfg, regulation, limits and simulation in libreg and DCCT, ADC and DAC calibration in libcal. These libraries were first used in the software class dedicated to controlling the new 60 MW main power converter (POPS) at the CERN Proton Synchrotron (CPS) where regulation of both magnetic field and circuit current is supported. This paper reports on the functionality provided by each library and in particular libfg and libreg. The libraries are already being used by software classes in development for the next generation FGC for Linac4 converters, as well as the CERN SPS converter controls (MUGEF) and MedAustron converter regulation board. (authors)

  14. A new proton spill from CERN to Gran Sasso

    CERN Multimedia

    CERN Bulletin

    2011-01-01

    Since 21 October, CERN has been sending a new type of neutrino beam to Gran Sasso. The new configuration is intended to allow the experiments to define the departure time of the neutrinos more accurately and thus check the previous results obtained using the nominal beam configuration.   The CERN Neutrino to Gran Sasso (CNGS) beam no longer operates using the standard beam time structure. Instead, a new type of proton pulse is being produced by CERN’s accelerators and sent to the graphite target to generate neutrinos. “We are now producing extremely short beam pulses,” explains Edda Gschwendtner, the physicist in charge of the CNGS secondary beam. “During a CNGS cycle we now have a LHC type bunched beam with four bunches, each about 2 ns long. Each bunch contains more than 2.5 x 1011 protons; bunches are spaced by 500 ns. In total, this makes about 1012 protons on target for each extraction from the SPS.” The CNGS beam was originally designed to m...

  15. The AEGIS experiment at CERN

    Energy Technology Data Exchange (ETDEWEB)

    Kellerbauer, A., E-mail: a.kellerbauer@cern.ch [Max Planck Institute for Nuclear Physics (Germany); Allkofer, Y.; Amsler, C. [University of Zurich, Physics Institute (Switzerland); Belov, A. S. [Institute for Nuclear Research of the Russian Academy of Sciences (Russian Federation); Bonomi, G. [University of Brescia, Department of Mechanical and Industrial Engineering (Italy); Braeunig, P. [University of Heidelberg, Kirchhoff Institute for Physics (Germany); Bremer, J. [European Organisation for Nuclear Research, Physics Department (Switzerland); Brusa, R. S. [University of Trento, Department of Physics (Italy); Burghart, G. [European Organisation for Nuclear Research, Physics Department (Switzerland); Cabaret, L. [Centre national de la recherche scientifique, Laboratoire Aime Cotton (France); Canali, C. [University of Zurich, Physics Institute (Switzerland); Castelli, F. [University of Milano, Department of Physics (Italy); Chlouba, K. [Czech Technical University in Prague, Department of Physics (Czech Republic); Cialdi, S. [University of Milano, Department of Physics (Italy); Comparat, D. [Centre national de la recherche scientifique, Laboratoire Aime Cotton (France); Consolati, G. [Politecnico di Milano, Department of Physics (Italy); Dassa, L. [University of Brescia, Department of Mechanical and Industrial Engineering (Italy); Noto, L. Di [University of Trento, Department of Physics (Italy); Donzella, A. [University of Brescia, Department of Mechanical and Industrial Engineering (Italy); Doser, M. [European Organisation for Nuclear Research, Physics Department (Switzerland); Collaboration: AEGIS Collaboration; and others

    2012-05-15

    After the first production of cold antihydrogen by the ATHENA and ATRAP experiments ten years ago, new second-generation experiments are aimed at measuring the fundamental properties of this anti-atom. The goal of AEGIS (Antimatter Experiment: Gravity, Interferometry, Spectroscopy) is to test the weak equivalence principle by studying the gravitational interaction between matter and antimatter with a pulsed, cold antihydrogen beam. The experiment is currently being assembled at CERN's Antiproton Decelerator. In AEGIS, antihydrogen will be produced by charge exchange of cold antiprotons with positronium excited to a high Rydberg state (n > 20). An antihydrogen beam will be produced by controlled acceleration in an electric-field gradient (Stark acceleration). The deflection of the horizontal beam due to its free fall in the gravitational field of the earth will be measured with a moire deflectometer. Initially, the gravitational acceleration will be determined to a precision of 1%, requiring the detection of about 10{sup 5} antihydrogen atoms. In this paper, after a general description, the present status of the experiment will be reviewed.

  16. The generation of arbitrary vector beams using a division of a wavefront-based setup

    Science.gov (United States)

    Kalita, Ranjan; Gaffar, Md; Boruah, Bosanta R.

    2016-07-01

    In this paper, we introduce an arbitrary vector-beam-forming scheme using a simple arrangement involving only one liquid crystal spatial light modulator. An arbitrary vector beam can be obtained by overlapping two orthogonally polarized beams. In most of the existing vector-beam-forming schemes the two orthogonally polarized beams are essentially copies of a single incident wavefront. However, in the proposed scheme the two orthogonally polarized beams correspond to two separated parts of a single incident wavefront. Taking a cue from the two-beam interference phenomenon, the present scheme can be referred to as a division of a wavefront-based scheme. The proposed setup offers certain important advantages and is more suitable for the generation of higher average-power vector beams. We demonstrate the working of the vector-beam-forming scheme by generating various vector beams such as radially polarized, azimuthally polarized, and Bessel-Gauss beams and also a boat-shaped beam in the focal volume of a low-numerical-aperture focusing lens. The boat-shaped beam comprises a dark center surrounded by intense light from all but one direction. The beam is realized at the focus of an azimuthally polarized beam in the presence of a moderate amount of coma in the beam. The experimental results obtained using the proposed setup are verified by comparing them with the theoretical results.

  17. Vibration problems in the design of the 95 MVA motor-generator set for the 28 GeV proton synchrotron at CERN

    CERN Document Server

    Geissler, Kryno K

    1972-01-01

    The main ring magnets of the 28 GeV proton synchrotron at CERN are pulse-excited from a motor generator. Power peaks of up to 70 MW cause torque shocks in the generator up to a maximum of 1 MNm (100 tonne m). The resulting vibrations must not be allowed to reach the ring magnets. The design of the machines presented a number of interesting dynamic problems. Two of the most important were the vibration of the flexibly supported foundation and the torsional vibration between the motor and generator which occurs when running on pulse duty and in the case of motor or generator line-to-line short-circuits. Measurements taken during commissioning showed that the operating performance was fully satisfactory and confirmed the design calculations. (4 refs).

  18. Neutrino oscillation experiments at CERN

    International Nuclear Information System (INIS)

    Two proposals for neutrino oscillation experiments have been submitted at CERN at this time. A Padova-Pisa-Athens-Wisconsin group proposes to use BEBC to observe ν/sub e/ events in a nearly pure ν/sub μ/ beam, and the CERN-Dortmund-Heidelberg-Saclay group proposes to use the neutrino detector presently installed in the SPS high energy neutrino beam to look for the disappearance of ν/sub μ/. The main features of the two experiments are presented and discussed

  19. Robot adventures at CERN

    CERN Multimedia

    2015-01-01

    Imagine if the CERN robots had an end-of-year party... From retrieving data tapes to handling material safely, the robots at CERN fulfill numerous tasks. Find out more: http://cern.ch/go/VjX7 Produced by: CERN Video Productions Director: Christoph M. Madsen Copyright © 2015 CERN. Terms of use: http://copyright.web.cern.ch/

  20. Study of Prompt Dimuon and Charm Production with Proton and Heavy Ion Beams at the CERN SPS

    CERN Multimedia

    Cicalo, C

    2002-01-01

    The NA60 detector complements the muon spectrometer and zero degree calorimeter previously used in NA50 with new state-of-the-art silicon detectors, placed in the target region. A radiation hard beam tracker, made of silicon microstrip detectors operated at 130 K, is placed on the beam line, upstream of the target system. It gives the transverse coordinates of the interaction point on the targets with a precision around 20 micron, allowing us to measure the offset of the muon tracks, and tag events where a pair of D mesons was produced. Downstream of the target system, and inside a dipole magnetic field of 2.5 T, we have a silicon tracking telescope, that tracks the charged particles and allows us to identify which one of them provides the best match to the muon measured in the muon spectrometer, placed behind a 5.5m silicon microstrip planes complemented by pixel planes. For the ion runs, the very high multiplicity of charged particles imposes the exclusive use of radiation tolerant pixel detectors.

  1. Generation of arbitrary order Bessel beams via 3D printed axicons at the terahertz frequency range.

    Science.gov (United States)

    Wei, Xuli; Liu, Changming; Niu, Liting; Zhang, Zhongqi; Wang, Kejia; Yang, Zhengang; Liu, Jinsong

    2015-12-20

    We present the generation of arbitrary order Bessel beams at 0.3 THz through the implementation of suitably designed axicons based on 3D printing technology. The helical axicons, which possess thickness gradients in both radial and azimuthal directions, can convert the incident Gaussian beam into a high-order Bessel beam with spiral phase structure. The evolution of the generated Bessel beams are characterized experimentally with a three-dimensional field scanner. Moreover, the topological charges carried by the high-order Bessel beams are determined by the fork-like interferograms. This 3D-printing-based Bessel beam generation technique is useful not only for THz imaging systems with zero-order Bessel beams but also for future orbital-angular-momentum-based THz free-space communication with higher-order Bessel beams. PMID:26837031

  2. CERN choir

    CERN Document Server

    2004-01-01

    Don't forget a special performance of Joseph Haydn's Creation, an oratorio in three parts, given by the CERN choir and the Annecy choir Pro Musica, this Sunday at 8.30 p.m. at the Grand Casino. Tickets (38 CHF) are available at Fnac Rive and Balexert.

  3. Robust Collimation Control of Laser-Generated Ion Beam

    OpenAIRE

    Kawata, S; Takano, M.; Kamiyama, D.; T. Nagashima; Barada, D.; Gu, Y. J.; Li, X; Yu, Q; Kong, Q.; Wang, P. X.

    2015-01-01

    The robustness of a structured collimation device is discussed for an intense-laser-produced ion beam. In this paper the ion beam collimation is realized by the solid structured collimation device, which produces the transverse electric field; the electric field contributes to reduce the ion beam transverse velocity and collimate the ion beam. Our 2.5 dimensional particle-in cell simulations demonstrate that the collimation device is rather robust against the changes in the laser parameters a...

  4. Photorefractive and computational holography in the experimental generation of Airy beams

    Science.gov (United States)

    Suarez, Rafael A. B.; Vieira, Tarcio A.; Yepes, Indira S. V.; Gesualdi, Marcos R. R.

    2016-05-01

    In this paper, we present the experimental generation of Airy beams via computational and photorefractive holography. Experimental generation of Airy beams using conventional optical components presents several difficulties and a practically infeasible. Thus, the optical generation of Airy beams has been made from the optical reconstruction of a computer generated hologram implemented by a spatial light modulator. In the photorefractive holography technique, being used for the first time to our knowledge, the hologram of an Airy beam is constructed (recorded) and reconstructed (read) optically in a nonlinear photorefractive medium. The Airy beam experimental realization was made by a setup of computational and photorefractive holography using a photorefractive Bi12 TiO20 crystal as holographic recording medium. Airy beams and Airy beam arrays were obtained experimentally in accordance with the predicted theory; with excellent prospects for applications in optical trapping and optical communications systems.

  5. Nonlinear evolution of Airy-like beams generated by modulated waveguide arrays.

    Science.gov (United States)

    Cao, Zheng; Tan, Qinggui; Li, Xiaojun; Qi, Xinyuan

    2016-08-20

    We numerically study the formation of modulated waveguide generated Airy-like beams and their subsequent evolution in homogeneous medium. The results show that the Airy-like beams could be generated from narrow Gaussian beams propagating in one-dimensional transverse separation modulated unbent, cosine bent, or logarithm bent waveguide arrays, respectively. The waveguide-generated Airy-like beams maintain their characteristics when propagating without nonlinearity or under the self-defocusing nonlinearity in homogeneous medium, while the beams are distorted under the self-focusing nonlinearity. The deformation depends on the waveguide bending and the outgoing angles of the Airy-like beams. Our results provide a new way to generate and manipulate the Airy-like beam.

  6. Photorefractive and computational holography in the experimental generation of Airy beams

    CERN Document Server

    Suarez, Rafael A B; Yepes, Indira S V; Gesualdi, Marcos R R

    2015-01-01

    In this paper, we present the experimental generation of Airy beams via computational and photorefractive holography. Experimental generation of Airy beams using conventional optical components presents several difficulties and are practically infeasible. Thus, the optical generation of Airy beams has been made from the optical reconstruction of a computer generated hologram implemented in a spatial light modulators. In the photorefractive holography technique, being used for the first time to our knowledge, the hologram of an Airy beam is constructed (recorded) and reconstructed (reading) optically in a nonlinear photorefractive medium. The Airy beam experimental realization was made by a setup of computational and photorefractive holography using a photorefractive Bi_{12}TiO_{20} crystal as holographic recording medium. Airy beams and Airy beam arrays were obtained experimentally as in accordance with the predicted theory; and present excellent prospects for applications in optical trapping and optical comm...

  7. Light ion beams generation in dense plasma focus

    International Nuclear Information System (INIS)

    The high energy deuterons and protons in a Mather type plasma focus device were measured by nuclear activation techniques. The radioactivity induced in graphite, aluminum and copper targets provided the deuteron intensity, energy spectra and angular dependence. High energy protons were measured by cellulose nitrate particle track detectors. The plasma focus device was operated at 30 kV for a stored energy of 18 kJ at 1.5 Torr D2 (low pressure mode), and 5 Torr D2 (high pressure mode). The yield ratio of N-13 and Al-28 showed the mean deuteron energy of 1.55 MeV under low pressure mode and of 1.44 MeV under high pressure mode. The deuteron energy spectra were measured by the stacks of 10 aluminum foils, and consisted of two components as well as the proton energy spectra measured by CN film technique. The angular spread of deuteron beam was within 30 degree under low pressure mode. Under high pressure mode, the distribution showed multi-structure, and two peaks were observed at the angle smaller than 20 degree and at 60 degree. The protons with energy more than 770 keV were directed in the angle of 10 degree. The high energy electron beam was also observed. A three-channel ruby laser holographic interferometry was used to see the spatial and temporal location of the generation of high energy ions. The ion temperature in plasma focus was estimated from D + He3 mixture gas experiment. (Kato, T.)

  8. Response and Shower Topology of 2 to 180 GeV Pions Measured with the ATLAS Barrel Calorimeter at the CERN Test-beam and Comparison to Monte Carlo Simulations

    CERN Document Server

    Abat, E; Addy, T N; Adragna, P; Aharrouche, M; Ahmad, A; Akesson, T P A; Aleksa, M; Alexa, C; Anderson, K; Andreazza, A; Anghinolfi, F; Antonaki, A; Arabidze, G; Arik, E; Atkinson, T; Baines, J; Baker, O K; Banfi, D; Baron, S; Barr, A J; Beccherle, R; Beck, H P; Belhorma, B; Bell, P J; Benchekroun, D; Benjamin, D P; Benslama, K; Bergeaas Kuutmann, E; Bernabeu, J; Bertelsen, H; Binet, S; Biscarat, C; Boldea, V; Bondarenko, V G; Boonekamp, M; Bosman, M; Bourdarios, C; Broklova, Z; Burckhart Chromek, D; Bychkov, V; Callahan, J; Calvet, D; Canneri, M; Capeans Garrido, M; Caprini, M; Cardiel Sas, L; Carli, T; Carminati, L; Carvalho, J; Cascella, M; Castillo, M V; Catinaccio, A; Cauz, D; Cavalli, D; Cavalli Sforza, M; Cavasinni, V; Cetin, S A; Chen, H; Cherkaoui, R; Chevalier, L; Chevallier, F; Chouridou, S; Ciobotaru, M; Citterio, M; Clark, A; Cleland, B; Cobal, M; Cogneras, E; Conde Muino, P; Consonni, M; Constantinescu, S; Cornelissen, T; Correard, S; Corso Radu, A; Costa, G; Costa, M J; Costanzo, D; Cuneo, S; Cwetanski, P; Da Silva, D; Dam, M; Dameri, M; Danielsson, H O; Dannheim, D; Darbo, G; Davidek, T; De, K; Defay, P O; Dekhissi, B; Del Peso, J; Del Prete, T; Delmastro, M; Derue, F; Di Ciaccio, L; Dita, S; Dittus, F; Djama, F; Djobava, T; Dobos, D; Dobson, M; Dolgoshein, B A; Dotti, A; Drake, G; Drasal, Z; Dressnandt, N; Driouchi, G; Drohan, J; Ebenstein, W L; Eerola, P; Eerola, P; Efthymiopoulos, I; Egorov, K; Eifert, T F; Einsweiler, K; El Kacimi, M; Elsing, M; Emelyanov, D; Escobar, C; Etienvre, A I; Fabich, A; Facius, K; Fakhr-Edine, A I; Fanti, M; Farbin, A; Farthouat, P; Fassouliotis, D; Fayard, L; Febbraro, R; Fedin, O L; Fenyuk, A; Fergusson, D; Ferrari, P; Ferrari, R; Ferreira, B C; Ferrer, A; Ferrere, D; Filippini, G; Flick, T; Fournier, D; Francavilla, P; Francis, D; Froeschl, R; Froidevaux, D; Fullana, E; Gadomski, S; Gagliardi, G; Gagnon, P; Gallas, M; Gallop, B J; Gameiro, S; Gan, K K; Garcia, R; Garcia, C; Gavrilenko, I L; Gemme, C; Gerlach, P; Ghodbane, N; Giakoumopoulou, V; Giangiobbe, V; Giokaris, N; Di Girolamo, B; Glonti, G; Goettfert, T; Golling, T; Gollub, N; Gomes, A; Gomez, M D; Gonzalez-Sevilla, S; Goodrick, M J; Gorfine, G; Gorini, B; Goujdami, D; Grahn, K J; Grenier, P; Grigalashvili, N; Grishkevich, Y; Grosse-Knetter, J; Gruwe, M; Guicheney, C; Gupta, A; Haeberli, C; Haertel, R; Hajduk, Z; Hakobyan, H; Hance, M; Hansen, D J; Hansen, P H; Hara, K; Harvey Jr, A; Hawkings, R J; Heinemann, F E W; Henriques Correia, A; Henss, T; Hervas, L; Higon, E; Hill, J C; Hoffman, J; Hostachy, J Y; Hruska, I; Hubaut, F; Huegging, F; Hulsbergen, W; Hurwitz, M; Iconomidou-Fayard, L; Jansen, E; Jen-La Plante, I; Johansson, P D C; Jon-And, K; Joos, M; Jorgensen, S; Joseph, J; Kaczmarska, A; Kado, M; Karyukhin, A; Kataoka, M; Kayumov, F; Kazarov, A; Keener, P T; Kekelidze, G D; Kerschen, N; Kersten, S; Khomich, A; Khoriauli, G; Khramov, E; Khristachev, A; Khubua, J; Kittelmann, T H; Klingenberg, R; Klinkby, E B; Kodys, P; Koffas, T; Kolos, S; Konovalov, S P; Konstantinidis, N; Kopikov, S; Korolkov, I; Kostyukhin, V; Kovalenko, S; Kowalski, T Z; Kruger, K; Kramarenko, V; Kudin, L G; Kulchitsky, Y; Le Bihan, A C; Lacasta, C; Lafaye, R; Laforge, B; Lampl, W; Lanni, F; Laplace, S; Lari, T; Latorre, S; Le Bihan, A C; Lechowski, M; Ledroit-Guillon, F; Lehmann, G; Leitner, R; Lelas, D; Lester, C G; Liang, Z; Lichard, P; Liebig, W; Lipniacka, A; Lokajicek, M; Louchard, L; Lourerio, K F; Lucotte, A; Luehring, F; Lund-Jensen, B; Lundberg, B; Ma, H; Mackeprang, R; Maio, A; Maleev, V P; Malek, F; Mandelli, L; Maneira, J; Mangin-Brinet, M; Manousakis, A; Mapelli, L; Marques, C; Marti i García, S; Martin, F; Mathes, M; Mazzanti, M; McFarlane, K W; McPherson, R; Mchedlidze, G; Mehlhase, S; Meirosu, C; Meng, Z; Meroni, C; Miagkov, A; Mialkovski, V; Mikulec, B; Milstead, D; Minashvili, I; Mindur, B; Mitsou, V A; Moed, S; Monnier, E; Moorhead, G; Morettini, P; Morozov, S V; Mosidze, M; Mouraviev, S V; Moyse, E W J; Munar, A; Nadtochi, A V; Nakamura, K; Nechaeva, P; Negri, A; Nemecek, S; Nessi, M; Nesterov, S Y; Newcomer, F M; Nikitine, I; Nikolaev, K; Nikolic-Audit, I; Ogren, H; Oh, S H; Oleshko, S B; Olszowska, J; Onofre, A; Padilla Aranda, C; Paganis, S; Pallin, D; Pantea, D; Paolone, V; Parodi, F; Parsons, J; Parzhitskiy, S; Pasqualucci, E; Passmore, M S; Pater, J; Patrichev, S; Peez, M; Perez Reale, V; Perini, L; Peshekhonov, V D; Petersen, J; Petersen, T C; Petti, R; Phillips, P W; Pilcher, J; Pina, J; Pinto, B; Podlyski, F; Poggioli, L; Poppleton, A; Poveda, J; Pralavorio, P; Pribyl, L; Price, M J; Prieur, D; Puigdengoles, C; Puzo, P; Rohne, O; Ragusa, F; Rajagopalan, S; Reeves, K; Reisinger, I; Rembser, C; Bruckman de Renstrom, P; Reznicek, P; Ridel, M; Risso, P; Riu, I; Robinson, D; Roda, C; Roe, S; Romaniouk, A; Rousseau, D; Rozanov, A; Ruiz, A; Rusakovich, N; Rust, D; Ryabov, Y F; Ryjov, V; Salto, O; Salvachua, B; Salzburger, A; Sandaker, H; Santamarina Rios, C; Santi, L; Santoni, C; Saraiva, J G; Sarri, F; Sauvage, G; Says, L P; Schaefer, M; Schegelsky, V A; Schiavi, C; Schieck, J; Schlager, G; Schlereth, J; Schmitt, C; Schultes, J; Schwemling, P; Schwindling, J; Seixas, J M; Seliverstov, D M; Serin, L; Sfyrla, A; Shalanda, N; Shaw, C; Shin, T; Shmeleva, A; Silva, J; Simion, S; Simonyan, M; Sloper, J E; Smirnov, S Yu; Smirnova, L; Solans, C; Solodkov, A; Solovianov, O; Soloviev, I; Sosnovtsev, V V; Spano, F; Speckmayer, P; Stancu, S; Stanek, R; Starchenko, E; Straessner, A; Suchkov, S I; Suk, M; Szczygiel, R; Tarrade, F; Tartarelli, F; Tas, P; Tayalati, Y; Tegenfeldt, F; Teuscher, R; Thioye, M; Tikhomirov, V O; Timmermans, C; Tisserant, S; Toczek, B; Tremblet, L; Troncon, C; Tsiareshka, P; Tyndel, M; Karagoez Unel, M; Unal, G; Unel, G; Usai, G; Van Berg, R; Valero, A; Valkar, S; Valls, J A; Vandelli, W; Vannucci, F; Vartapetian, A; Vassilakopoulos, V I; Vasilyeva, L; Vazeille, F; Vernocchi, F; Vetter-Cole, Y; Vichou, I; Vinogradov, V; Virzi, J; Vivarelli, I; De Vivie, J B; Volpi, M; Vu Anh, T; Wang, C; Warren, M; Weber, J; Weber, M; Weidberg, A R; Weingarten, J; Wells, P S; Werner, P; Wheeler, S; Wiessmann, M; Wilkens, H; Williams, H H; Wingerter-Seez, I; Yasu, Y; Zaitsev, A; Zenin, A; Zenis, T; Zenonos, Z; Zhang, H; Zhelezko, A; Zhou, N

    2010-01-01

    The response of the ATLAS barrel calorimeter to pions with momenta from $2$ to $180$~GeV~ is studied in a test--beam at the CERN H8 beam line. %Various methods to reconstruct the deposited pion energies are studied. The mean energy, the energy resolution and the longitudinal and radial shower profiles, and, various observables characterising the shower topology in the calorimeter are measured. The data are compared to Monte Carlo simulations based on a detailed description of the experimental set--up and on various models describing the interaction of particles with matter based on Geant4.

  9. Bulgarian folk dances at CERN

    CERN Multimedia

    Roberto Cantoni

    2010-01-01

    On Sunday 29 August, the Bulgarian folklore dance group Rhythm visited CERN. After their visit to the ATLAS visitor centre and the SM18 hall, they performed a show in the Pump Room, introducing CERN people to the musical traditions of their country.   The visit of the Bulgarian dance group was organized by Zornitsa Zaharieva, a member of the Beams Department, and Svejina Dimitrova, Director of the Varna Astronomical Observatory. “The students were enthusiastic about the opportunity to visit CERN”, says Zornitsa. “The idea of the performance came from the dance group itself, who wanted to express their gratitude for being given this chance”. The group, comprising around 25 children aged between 11 and 16 from the city of Varna, was hosted by the CERN Dancing Club. For their show, the young dancers, choreographed by Tashka Pavlova, performed traditional dances and songs from different Bulgarian regions. “As a member of the CERN Dancing Club com...

  10. Helico-conical beams for generating optical twisters

    DEFF Research Database (Denmark)

    Glückstad, Jesper; Palima, Darwin; Daria, Vincent Ricardo Mancao

    2010-01-01

    We describe a diffracting beam with orbital angular momentum (DAM) but with a helical profile in both phase and amplitude of the beam. This is different from Laguerre-Gaussian (LG) beams where only the phase component has a helical profile. The beam we describe here is initially characterized with...... an apodized helical phase front at the outskirts and linearly scaled towards no phase singularity at the centre of the beam. At the focal volume, we show that our beam fonms an intensity distribution that can be accurately described as an "optical twister" as it propagates along the optical axis....... Unlike LG beams, an optical twister can have minimal changes in radius but with a scalable DAM. Furthenmore, we characterize the DAM in tenms of its capacity to introduce spiral motion on particles trapped along its orbit. We also show that our "optical twister" maintains a high concentration of photons...

  11. CLOUD an atmospheric research facility at CERN

    CERN Document Server

    Fastrup, B; Lillestøl, Egil; Bosteels, Michel; Gonidec, A; Kirkby, Jasper; Mele, S; Minginette, P; Nicquevert, Bertrand; Schinzel, D; Seidl, W; Grundsøe, P; Marsh, N D; Polny, J; Svensmark, H; Viisanen, Y; Kurvinen, K L; Orava, Risto; Hameri, K; Kulmala, M; Laakso, I; O'Dowd, C D; Afrosimov, V; Basalaev, A; Panov, M; Laaksonen, B D; Joutsensaari, J; Ermakov, V; Makhmutov, V S; Maksumov, O; Pokrevsky, P; Stozhkov, Yu I; Svirzhevsky, N S; Carslaw, K; Yin, Y; Trautmann, T; Arnold, F; Wohlfrom, K H; Hagen, D; Schmitt, J; Whitefield, P; Aplin, K L; Harrison, R G; Bingham, R; Close, Francis Edwin; Gibbins, C; Irving, A; Kellett, B; Lockwood, M; Mäkelä, J M; Petersen, D; Szymanski, W W; Wagner, P E; Vrtala, A; CERN. Geneva. SPS-PS Experiments Committee

    2001-01-01

    This report is the second of two addenda to the CLOUD proposal at CERN (physics/0104048), which aims to test experimentally the existence a link between cosmic rays and cloud formation, and to understand the microphysical mechanism. The document places CLOUD in the framework of a CERN facility for atmospheric research, and provides further details on the particle beam requirements.

  12. CLOUD: an atmospheric research facility at CERN

    OpenAIRE

    The Cloud Collaboration

    2001-01-01

    This report is the second of two addenda to the CLOUD proposal at CERN (physics/0104048), which aims to test experimentally the existence a link between cosmic rays and cloud formation, and to understand the microphysical mechanism. The document places CLOUD in the framework of a CERN facility for atmospheric research, and provides further details on the particle beam requirements.

  13. Generation of antitropic electron beams by self-generated electric field. Kinetic description

    CERN Document Server

    Stepanov, N S

    2016-01-01

    This paper makes use of a one-dimensional kinetic model to investigate the nonlinear longitudinal dynamics of electron beams generated in the plasma under the influence of a self-generated electric field. It is expressed as where is a wave potential, , and charge particle distribution functions satisfy the Vlasov equation. It is proved that its correct solution is characterized by sudden change in the resonant part of the distribution function. Hence, in particular, the incorrectness of the established in the literature point of view follows that the fast, with velocities over V, and slow, with velocities under V, trapped particles are described by the same distribution function. Also for the first time it is shown that the self-generated strong electric field always produces antitropic electron beams with the velocities much larger than the value V, including the cold plasma limit. The possibility of implementing a new class of self-consistent wave structures with a nonzero average potential is shown. Maximu...

  14. CERN Shuttle

    CERN Multimedia

    General Infrastructure Services Department

    2011-01-01

    As of Monday 21 February, a new schedule will come into effect for the Airport Shuttle (circuit No. 4) at the end of the afternoon: Last departure at 7:00 pm from Main Buildig, (Bldg. 500) to Airport (instead of 5:10 p.m.); Last departure from Airport to CERN, Main Buildig, (Bldg. 500), at 7:30 p.m. (instead of 5:40 p.m.). Group GS-IS

  15. Generation and application of the twisted beam with orbital angular momentum

    Institute of Scientific and Technical Information of China (English)

    Mingwei Gao; Chunqing Gao; Zhifeng Lin

    2007-01-01

    The twisted Laguerre-Gaussian beam was generated by transforming of Hermite-Gaussian beams through an optical system consisting of three rotated cylindrical lenses. The intensity distribution and phase structure of the twisted hollow beam were theoretically analyzed by using Collins diffraction integral. By utilizing the method of mode decomposition, the theory of transformation was analyzed. In the experiment,micro particles were trapped and rotated by this twisted beam.

  16. Generation of Vortex Beams with Strong Longitudinally Polarized Magnetic Field by Using a Metasurface

    OpenAIRE

    Veysi, Mehdi; Guclu, Caner; Capolino, Filippo

    2014-01-01

    A novel method of generation and synthesis of azimuthally E-polarized vortex beams is presented. Along the axis of propagation such beams have a strong longitudinally polarized magnetic field where ideally there is no electric field. We show how these beams can be constructed through the interference of Laguerre-Gaussian beams carrying orbital angular momentum. As an example, we present a metasurface made of double-split ring slot pairs and report a good agreement between simulated and analyt...

  17. Polar POLICRYPS Diffractive Structures Generate Cylindrical Vector Beams

    CERN Document Server

    Alj, Domenico; Volpe, Giovanni; Caputo, Roberto; Umeton, Cesare

    2015-01-01

    Local shaping of the polarization state of a light beam is appealing for a number of applications. This can be achieved by employing devices containing birefringent materials. In this article, we present one such device that permits one to convert a uniformly circularly polarized beam into a cylindrical vector beam (CVB). This device has been fabricated by exploiting the POLICRYPS photocuring technique. It is a liquid-crystal-based optical diffraction grating featuring polar symmetry of the director alignment. We have characterized the resulting CVB profile and polarization for the cases of left and right circularly polarized incoming beams.

  18. Polar POLICRYPS diffractive structures generate cylindrical vector beams

    Energy Technology Data Exchange (ETDEWEB)

    Alj, Domenico; Caputo, Roberto, E-mail: roberto.caputo@fis.unical.it; Umeton, Cesare [Department of Physics and CNR-NANOTEC University of Calabria, I-87036 Rende (CS) (Italy); Paladugu, Sathyanarayana [Soft Matter Lab, Department of Physics, Bilkent University, Ankara 06800 (Turkey); Volpe, Giovanni [Soft Matter Lab, Department of Physics, Bilkent University, Ankara 06800 (Turkey); UNAM-National Nanotechnology Research Center, Bilkent University, Ankara 06800 (Turkey)

    2015-11-16

    Local shaping of the polarization state of a light beam is appealing for a number of applications. This can be achieved by employing devices containing birefringent materials. In this article, we present one such enables converting a uniformly circularly polarized beam into a cylindrical vector beam (CVB). This device has been fabricated by exploiting the POLICRYPS (POlymer-LIquid CRYstals-Polymer-Slices) photocuring technique. It is a liquid-crystal-based optical diffraction grating featuring polar symmetry of the director alignment. We have characterized the resulting CVB profile and polarization for the cases of left and right circularly polarized incoming beams.

  19. Diode with magnetic insulation and Br field as a generator of power microsecond ion beam

    International Nuclear Information System (INIS)

    Results of investigations into the generation of microsecond duration high-power ion beam in a plane magnetoisolated diode with an external isolating field with radial distribution are presented. The investigations are conducted using a microsecond generator operating in the regime of generating positive high-voltage ≤600 kV amplitude pulses. Ring-type cross section ion beam consisting mainly of H+ and C+ ions is studied. The energy range occupied by the major part of the ions generated makes up 300-500 keV. The complete energy store of the beam extracted from the diode makes up 10 kJ, the generation efficiency is 60%

  20. Cern collisions light up Copenhagen

    CERN Multimedia

    Banks, Michael

    2010-01-01

    "Anyone passing by the Niels Bohr Institute in Copenhagen, Denmark, might be startled by some strange moving lights on the facade of the institute's main building. In fact, the dancing beams show, almost in real time, collisions form the Atlas experiment at Cern's Large Hadron Collider (LHC)" (1 paragraph)

  1. The NOMAD Experiment at CERN

    CERN Document Server

    Vannucci, F

    2014-01-01

    The purpose of this paper is to review the experimental apparatus and some physics results fromthe NOMAD(neutrino oscillation magnetic detector) experiment which took data in the CERN wide-band neutrino beam from 1995 to 1998. It collected and reconstructed more than one million charged current(CC)$\

  2. Experimental generation of Mathieu-Gauss beams with a phase-only spatial light modulator.

    Science.gov (United States)

    Hernández-Hernández, R J; Terborg, R A; Ricardez-Vargas, I; Volke-Sepúlveda, K

    2010-12-20

    We present a novel method for the efficient generation of even, odd, and helical Mathieu-Gauss beams of arbitrary order and ellipticity by means of a phase-only spatial light modulator (SLM). Our method consists of displaying the phase of the desired beam in the SLM; the reconstructed field is obtained on-axis following a spatial filtering process with an annular aperture. The propagation invariance and topological properties of the generated beams are investigated numerically and experimentally. PMID:21173824

  3. A heatwave at CERN

    CERN Multimedia

    Anaïs Schaeffer

    2011-01-01

    It's getting hot in Buildings 201 and 860, over-heating even... But no reason to panic! We're talking about the superheated water boilers of CERN's two heating plants, which heat all the buildings on the Meyrin and Prévessin sites.   View of the three boilers and the control centre of the Meyrin heating plant. CERN's two heating plants each comprise three gas* boilers, with generators of 15 MW in the case of Meyrin and 5 MW in the case of Prévessin. Both inject pressurised water, superheated to 125 degrees, into several kilometres of pipes, 22 km on the Meyrin site and 5 km in Prévessin. "A single boiler is sufficient most of the time but a second kicks in automatically during very cold weather, and a third is there on stand-by," explains Christophe Martel, head of the GS Department section responsible for CERN's heating and air-conditioning systems. All of CERN's buildings have a sub-station that receives the superheated water from the boilers an...

  4. A novel laser beam generator in place at SGll

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    @@ Researchers with the State Key Laboratory of High Field Laser Physics, the CAS Shanghai Institute of Optics and Fine Mechanics, have been successful in developing a multifunctional and high-energy laser beam system (also known as the ninth laser beam) at the Shenguang-II Laser Facility (SGII).

  5. Contribution of longitudinal electric field of a gaussian beam to second harmonic generation

    Science.gov (United States)

    Mishra, S. R.; Rustagi, K. C.

    1990-01-01

    A laser beam with a nonuniform transverse intensity profile necessarily has a longitudinal component of the electric field. We show that a detectable second harmonic can be generated due to coupling of this longitudinal component with the transverse field of a gaussian beam in a configuration in which second harmonic generation is forbidden for plane wave interaction.

  6. The Utrecht 850 kV cascade generator I. Beam deflection and energy control

    NARCIS (Netherlands)

    Braams, C.M.; Smith, P.B.

    1960-01-01

    The beam deflection magnet and energy control system of the Utrecht cascade generator are described. The uniform-field magnet has entrance and exit slits located outside the magnetic held. Since the cascade generator produces a vertical beam, the most convenient choice for the angle of deflection wa

  7. Spotlight on CERN

    CERN Multimedia

    CERN video productions

    2009-01-01

    Welcome to the Globe of Science and Innovation for the first "Spotlight on CERN" just a few weeks before the restart of the LHC machine. Today our guest is Mike Lamont, who is in charge of the Operations Group for the accelerator beams. This weekend, protons were injected into the LHC for the first time since September 2008. But before we talk about that, let's go back a few weeks and look at the previous stage, which involved testing the transfer lines of the injection tunnels TI2/TI8. Our video team was there to film this operation.

  8. Production of events with two or three muons in the final state during the interaction on nucleons of neutrinos and anti-neutrinos of the CERN narrow band beam with a maximum energy of 200 GeV

    International Nuclear Information System (INIS)

    A study was made of the production of dimuons and trimuons in the neutrino interactions using the data of the CDHS (CERN-Dortmund-Heidelberg-Saclay Cooperation) experiment taken in the CERN narrow band beam. The analysis of the quick results (since the statistics are weak) leads to significant conclusions on these events: 1) the c quark fragmentation function is approximately flat, 2) the production of heavy leptons, if this exists, only represents a very small part of the charged currents (10-4 approximately). 3) the pair production of charmed quarks can explain some of the dimuons of same sign, the greater part of these events coming from the semi leptonic disintegration of pions and kaons (π→μν,K → μν) produced in the hadronic jet. 4) any other process (for instance the production of b quarks) is very weak (-3 of the charged currents)

  9. Generation of spatial Bessel beams using holographic metasurface.

    Science.gov (United States)

    Cai, Ben Geng; Li, Yun Bo; Jiang, Wei Xiang; Cheng, Qiang; Cui, Tie Jun

    2015-03-23

    We propose to use backward radiations of leaky waves supported by a holographic metasurface to produce spatial Bessel beams in the microwave frequency regime. The holographic metasurface consists of a grounded dielectric slab and a series of metal patches. By changing the size of metal patches, the surface-impedance distribution of the holographic metasurface can be modulated, and hence the radiation properties of the leaky waves can be designed to realize Bessel beams. Both numerical simulations and experiments verify the features of spatial Bessel beams, which may be useful in imaging applications or wireless power transmissions with the dynamic focal-depth controls. PMID:25837097

  10. A second-generation ion beam buncher and cooler

    CERN Document Server

    Schwarz, S; Lawton, D; Neudert, A; Ringle, R; Schury, P; Sun, T

    2003-01-01

    A radiofrequency quadrupole (RFQ) ion accumulator and buncher has been designed for the low-energy beam and ion-trap (LEBIT) facility which is being set up at the NSCL/MSU. The LEBIT buncher will be a cryogenic system. Compared to room-temperature systems an improved beam quality and overall efficiency are expected. It will feature a novel electrode structure with a drastically reduced number of electrodes for simplified operation. Its design is presented and Monte-Carlo type ion-trajectory calculations are discussed which predict excellent beam quality and high performance.

  11. Laser beam propagation generation and propagation of customized light

    CERN Document Server

    Forbes, Andrew

    2014-01-01

    ""The text is easy to read and is accompanied by beautiful illustrations. It is an excellent book for anyone working in laser beam propagation and an asset for any library.""-Optics & Photonics News, July 2014

  12. Measurements of Terahertz Generation in a Metallic, Corrugated Beam Pipe

    CERN Document Server

    Bane, K L F; Fedurin, M; Kusche, K; Swinson, C; Xiang, D

    2016-01-01

    A method for producing narrow-band THz radiation proposes passing an ultra-relativistic beam through a metallic pipe with small periodic corrugations. We present results of a measurement of such an arrangement at Brookhaven's Accelerator Test Facility (ATF). Our pipe was copper and was 5 cm long; the aperture was cylindrically symmetric, with a 1 mm (radius) bore and a corrugation depth (peak-to-peak) of 60 um. In the experiment we measured both the effect on the beam of the structure wakefield and the spectral properties of the radiation excited by the beam. We began by injecting a relatively long beam compared to the wavelength of the radiation to excite the structure, and then used a downstream spectrometer to infer the radiation wavelength. This was followed by injecting a shorter bunch, and then using an interferometer (also downstream of the corrugated pipe) to measure the spectrum of the induced THz radiation.

  13. Return Current Electron Beams and Their Generation of "Raman" Scattering

    Science.gov (United States)

    Simon, A.

    1998-11-01

    For some years, we(A. Simon and R. W. Short, Phys. Rev. Lett. 53), 1912 (1984). have proposed that the only reasonable explanation for many of the observations of "Raman" scattering is the presence of an electron beam in the plasma. (The beam creates a bump-on-tail instability.) Two major objections to this picture have been observation of Raman when no n_c/4 surface was present, with no likely source for the electron beam, and the necessity for the initially outward directed beam to bounce once to create the proper waves. Now new observations on LLE's OMEGA(R. Petrasso et al), this conference. and at LULI(C. Labaune et al)., Phys. Plasma 5, 234 (1998). have suggested a new origin for the electron beam. This new scenario answers the previous objections, maintains electron beams as the explanation of the older experiments, and may clear up puzzling observations that have remained unexplained. The new scenario is based on two assumptions: (1) High positive potentials develop in target plasmas during their creation. (2) A high-intensity laser beam initiates spark discharges from nearby surfaces to the target plasma. The resulting return current of electrons should be much more delta-like, is initially inwardly directed, and no longer requires the continued presence of a n_c/4 surface. Scattering of the interaction beam from the BOT waves yields the observed Raman signal. Experimental observations that support this picture will be cited. ``Pulsation'' of the scattering and broadband ``flashes'' are a natural part of this scenario. This work was supported by the U.S. Department of Energy Office of Inertial Confinement Fusion under Cooperative Agreement No. DE-FC03-92SF19460.

  14. Generation of intense pulsed electron beams by the pseudospark discharge

    International Nuclear Information System (INIS)

    A low-pressure gas discharge is presented as a source of intense pulsed electron beams. The so-called pseudospark discharge emits a short-duration pinched electron beam during the breakdown phase. At voltages of typically 20 kV, approximately 10 to 20 percent of the total discharge current appears as the electron beam current of typically 20 ns induration. According to the breakdown voltage in the beam, a power density of the order of 109 W/cm2 is reached. Thus, this electron beam turns out to be a good tool for material processing, comparable to pulsed high-power lasers. Besides the drilling of holes into metals and insulators, an interesting application is the production of high-temperature superconducting thin YBa2Cu3O7-x films. The electron beam is used to evaporate material from a stoichiometric 1-2-3 target. Experimental results concerning the propagation behavior in neutral gas, the electron energy distribution, and the interaction with matter are reported

  15. Direct patterning of vortex generators on a fiber tip using a focused ion beam.

    Science.gov (United States)

    Vayalamkuzhi, Pramitha; Bhattacharya, Shanti; Eigenthaler, Ulrike; Keskinbora, Kahraman; Samlan, C T; Hirscher, Michael; Spatz, Joachim P; Viswanathan, Nirmal K

    2016-05-15

    The realization of spiral phase optical elements on the cleaved end of an optical fiber by focused ion beam milling is presented. A focused Ga+ ion beam with an acceleration voltage of 30 keV is used to etch continuous spiral phase plates and fork gratings directly on the tip of the fiber. The phase characteristics of the output beam generated by the fabricated structures measured via an interference experiment confirmed the presence of phase singularity in the output beam. The devices are expected to be promising candidates for all-fiber beam shaping and optical trapping applications.

  16. Direct patterning of vortex generators on a fiber tip using a focused ion beam.

    Science.gov (United States)

    Vayalamkuzhi, Pramitha; Bhattacharya, Shanti; Eigenthaler, Ulrike; Keskinbora, Kahraman; Samlan, C T; Hirscher, Michael; Spatz, Joachim P; Viswanathan, Nirmal K

    2016-05-15

    The realization of spiral phase optical elements on the cleaved end of an optical fiber by focused ion beam milling is presented. A focused Ga+ ion beam with an acceleration voltage of 30 keV is used to etch continuous spiral phase plates and fork gratings directly on the tip of the fiber. The phase characteristics of the output beam generated by the fabricated structures measured via an interference experiment confirmed the presence of phase singularity in the output beam. The devices are expected to be promising candidates for all-fiber beam shaping and optical trapping applications. PMID:27176945

  17. Generation mechanism of whistler waves produced by electron beam injection in space

    Science.gov (United States)

    Pritchett, P. L.; Karimabadi, H.; Omidi, N.

    1989-01-01

    Electromagnetic particle simulations are used to determine the generation mechanism of the whistler waves observed in connection with the artificial injection of electron beams in the ionosphere. The production of the waves is shown to be closely connected with the beam-plasma interaction, which leads to the formation of a current structure which acts like an antenna and emits the whistler waves in a coherent manner. This process, in contrast to a mechanism involving amplification of radiation by a whistler mode plasma instability within the beam, allows the whistlers to be generated even though the beam width is less than one wavelength.

  18. Generation of cylindrical vector beams of high orders using uniaxial crystals

    International Nuclear Information System (INIS)

    The generation of cylindrical vector beams in birefringent crystals is studied analytically and experimentally in paraxial and non-paraxial regimes. At sharp focusing (in the non-paraxial case), two foci corresponding ordinary and extraordinary beams are formed along the crystal’s axis. There is the radially polarized distribution in one focus and the azimuthally polarized distribution in the other focus when the incident beam has the vortex phase of the first order and circular polarization of the opposite direction. The results are extended to the generation of higher-order radially and azimuthally polarized laser beams. The physical experiments with an Iceland spar crystal have been conducted. (paper)

  19. CERN moves to http://home.cern

    CERN Multimedia

    2015-01-01

    A new top-level domain for CERN will be inaugurated next week, with the migration of the core website to http://home.cern.   The new home.cern webpage. The .cern top-level domain is intended for the exclusive use of CERN and its affiliates, and will soon be open for applications from within the community. Clear governance mechanisms for registration and management of .cern domains have been put in place. Applications for domains may be submitted by current members of the CERN personnel, and must be sponsored by a CERN entity such as a department, experiment, project or CERN-recognised experiment. For more information please refer to the registration policy. The acquisition of the .cern top-level domain was negotiated via ICANN’s new gTLD programme by a board comprising members of the CERN Legal Service, Communications group and IT department. .cern is one of over 1,300 new top-level domains that will launch over the coming months and years. The .cern domain nam...

  20. UK @ CERN

    CERN Multimedia

    FI Department

    2008-01-01

    17 – 18 November 2008 9.00 a.m. - 5.00 p.m. on Monday 17 November 9.00 a.m. - 5.00 p.m. on Tuesday 18 November Individual meetings will take place in the technicians’ or engineers’ offices. The companies will contact relevant users/technicians but anyone wishing to arrange an appointment with a specific company can contact Caroline Laignel (mailto:caroline.laignel@cern.ch, tel. 73722). A list of the companies is available from all departmental secretariats and on the web at: http://fi-dep.web.cern.ch/fi-dep/structure/memberstates/exhibitions_visits.htm List of companies: 1. Caburn MDC Europe Ltd. 2. Croft Engineering Services 3. Cryox Ltd. 4. Goodfellow Cambridge Ltd. 5. Gravatom Engineering Systems Ltd. 6. High Voltage Technology 7. Lilco Ltd. 8. Micro Metalsmiths Ltd. 9. Photek Ltd. 10. Shadow Robot Company 11. Sundance Multiprocessor Technology Ltd. 12. Tessella plc 13. Thermal Resources Management Ltd. 14. Torr Scientific Ltd. For further information please contact Mrs C. Laignel, FI-DI, tel. 7372...

  1. High current density sheet-like electron beam generator

    Science.gov (United States)

    Chow-Miller, Cora; Korevaar, Eric; Schuster, John

    Sheet electron beams are very desirable for coupling to the evanescent waves in small millimeter wave slow-wave circuits to achieve higher powers. In particular, they are critical for operation of the free-electron-laser-like Orotron. The program was a systematic effort to establish a solid technology base for such a sheet-like electron emitter system that will facilitate the detailed studies of beam propagation stability. Specifically, the effort involved the design and test of a novel electron gun using Lanthanum hexaboride (LaB6) as the thermionic cathode material. Three sets of experiments were performed to measure beam propagation as a function of collector current, beam voltage, and heating power. The design demonstrated its reliability by delivering 386.5 hours of operation throughout the weeks of experimentation. In addition, the cathode survived two venting and pump down cycles without being poisoned or losing its emission characteristics. A current density of 10.7 A/sq cm. was measured while operating at 50 W of ohmic heating power. Preliminary results indicate that the nearby presence of a metal plate can stabilize the beam.

  2. Generating a Bessel-Gaussian beam for the application in optical engineering.

    Science.gov (United States)

    Chu, Xiuxiang; Sun, Quan; Wang, Jing; Lü, Pin; Xie, Wenke; Xu, Xiaojun

    2015-01-01

    Bessel beam is the important member of the family of non-diffracting beams and has many novel properties which can be used in many areas. However, the source of Bessel beam generated by the existing methods can be used only in a short distance due to its low power. In this paper, based on the coherent combining technology, we have proposed a method which can be used to generate a high-power Bessel beam. Even more, we give an innovative idea to form vortex phase by using discontinuous piston phase. To confirm the validity of this method, the intensity evolution of the combined beam and the Bessel-Gaussian beam at different propagation distance have been studied and compared. Meanwhile, the experimental realization has been discussed from the existing experimental result related to the coherent combining technology. PMID:26690264

  3. Generation of optical vortex dipole from superposition of two transversely scaled Gaussian beams.

    Science.gov (United States)

    Naik, Dinesh N; Pradeep Chakravarthy, T; Viswanathan, Nirmal K

    2016-04-20

    We propose a distinct concept on the generation of optical vortex through coupling between the amplitude and phase differences of the superposing beams. For the proof-of-concept demonstration, we propose a simple free-space optics recipe for the controlled synthesis of an optical beam with a vortex dipole by superposing two transversely scaled Gaussian beams. The experimental demonstration using a Sagnac interferometer introduces the desired amount of radial shear and linear phase difference between the two out-of-phase Gaussian beams to create a vortex pair of opposite topological charge in the superposed beam. Flexibility to tune their location and separation using the choice of direction of the linear phase difference and the amount of amplitude difference between the superposing beams has potential applications in optical tweezers and traps utilizing the local variation in angular momentum across the beam cross section.

  4. Graphic processing unit accelerated real-time partially coherent beam generator

    Science.gov (United States)

    Ni, Xiaolong; Liu, Zhi; Chen, Chunyi; Jiang, Huilin; Fang, Hanhan; Song, Lujun; Zhang, Su

    2016-07-01

    A method of using liquid-crystals (LCs) to generate a partially coherent beam in real-time is described. An expression for generating a partially coherent beam is given and calculated using a graphic processing unit (GPU), i.e., the GeForce GTX 680. A liquid-crystal on silicon (LCOS) with 256 × 256 pixels is used as the partially coherent beam generator (PCBG). An optimizing method with partition convolution is used to improve the generating speed of our LC PCBG. The total time needed to generate a random phase map with a coherence width range from 0.015 mm to 1.5 mm is less than 2.4 ms for calculation and readout with the GPU; adding the time needed for the CPU to read and send to LCOS with the response time of the LC PCBG, the real-time partially coherent beam (PCB) generation frequency of our LC PCBG is up to 312 Hz. To our knowledge, it is the first real-time partially coherent beam generator. A series of experiments based on double pinhole interference are performed. The result shows that to generate a laser beam with a coherence width of 0.9 mm and 1.5 mm, with a mean error of approximately 1%, the RMS values needed 0.021306 and 0.020883 and the PV values required 0.073576 and 0.072998, respectively.

  5. Generation of a family of Pearcey beams based on Fresnel diffraction catastrophes

    International Nuclear Information System (INIS)

    Based on the theory of differential geometry and Fresnel diffraction catastrophes, we theoretically prove that the cusped caustic of Pearcey beams are the evolute of a parabola and thus identify the key factor determining the optical structure of Pearcey beams. We numerically simulate and experimentally generate a family of Pearcey beams with various optical topological structures using different parabolas. We then investigate their optical structures and propagation properties. (paper)

  6. Dynamic photorefractive self-amplified angular-multiplex 2-D optical beam-array generation

    Science.gov (United States)

    Zhou, Shaomin; Yeh, Pochi; Liu, Hua-Kuang

    1993-01-01

    A real-time 2-D angular-multiplex beam-array holographic storage and reconstruction technique using electrically-addressed spatial light modulators(E-SLM's) and photorefractive crystals is described. Using a liquid crystal television (LCTV) spatial light modulator (SLM) for beam steering and lithium niobate photorefractive crystal for holographic recording, experimental results of generating large and complicated arrays of laser beams with high diffraction efficiency and good uniformity are presented.

  7. Generation of diffraction-free plasmonic beams with one-dimensional Bessel profiles

    DEFF Research Database (Denmark)

    García Ortíz, César Eduardo; Coello, Victor; Han, Zhanghua;

    2013-01-01

    We demonstrate experimentally generation of diffraction-free plasmonic beams with zeroth- and first-order Bessel intensity profiles using axicon-like structures fabricated on gold film surfaces and designed to operate at a wavelength of 700nm. The central beam features a very low divergence (∼8π...... mrad) for a narrow waist of the order of one wavelength and the ability to self reconstruct, which are the main signatures of diffraction-free beams...

  8. Underlying conservation and stability laws in nonlinear propagation of axicon-generated Bessel beams

    OpenAIRE

    Porras, Miguel A,; Ruiz-Jimenez, Carlos; Losada, Juan Carlos

    2015-01-01

    In light filamentation induced by axicon-generated, powerful Bessel beams, the spatial propagation dynamics in the nonlinear medium determines the geometry of the filament channel and hence its potential applications. We show that the observed steady and unsteady Bessel beam propagation regimes can be understood in a unified way from the existence of an attractor and its stability properties. The attractor is identified as the nonlinear unbalanced Bessel beam (NL-UBB) whose inward H\\"ankel be...

  9. Hollow Gaussian beam generation through nonlinear interaction of photons with orbital angular momentum

    Science.gov (United States)

    Chaitanya, N. Apurv; Jabir, M. V.; Banerji, J.; Samanta, G. K.

    2016-09-01

    Hollow Gaussian beams (HGB) are a special class of doughnut shaped beams that do not carry orbital angular momentum (OAM). Such beams have a wide range of applications in many fields including atomic optics, bio-photonics, atmospheric science, and plasma physics. Till date, these beams have been generated using linear optical elements. Here, we show a new way of generating HGBs by three-wave mixing in a nonlinear crystal. Based on nonlinear interaction of photons having OAM and conservation of OAM in nonlinear processes, we experimentally generated ultrafast HGBs of order as high as 6 and power >180 mW at 355 nm. This generic concept can be extended to any wavelength, timescales (continuous-wave and ultrafast) and any orders. We show that the removal of azimuthal phase of vortices does not produce Gaussian beam. We also propose a new and only method to characterize the order of the HGBs.

  10. Hollow Gaussian beam generation through nonlinear interaction of photons with orbital-angular-momemtum

    CERN Document Server

    Chaitanya, N Apurv; Banerji, J; Samanta, G K

    2016-01-01

    Hollow Gaussian beams (HGB) are a special class of doughnut shaped beams that do not carry orbital angular momentum (OAM). Such beams have a wide range of applications in many fields including atomic optics, bio-photonics, atmospheric science, and plasma physics. Till date, these beams have been generated using linear optical elements. Here, we show a new way of generating HGBs by three-wave mixing in a nonlinear crystal. Based on nonlinear interaction of photons having OAM and conservation of OAM in nonlinear processes, we experimentally generated ultrafast HGBs of order as high as 6 and power >180 mW at 355 nm. This generic concept can be extended to any wavelength, timescales (continuous-wave and ultrafast) and any orders. We show that the removal of azimuthal phase of vortices does not produce Gaussian beam. We also propose a new and only method to characterize the order of the HGBs.

  11. Hollow Gaussian beam generation through nonlinear interaction of photons with orbital angular momentum.

    Science.gov (United States)

    Chaitanya, N Apurv; Jabir, M V; Banerji, J; Samanta, G K

    2016-01-01

    Hollow Gaussian beams (HGB) are a special class of doughnut shaped beams that do not carry orbital angular momentum (OAM). Such beams have a wide range of applications in many fields including atomic optics, bio-photonics, atmospheric science, and plasma physics. Till date, these beams have been generated using linear optical elements. Here, we show a new way of generating HGBs by three-wave mixing in a nonlinear crystal. Based on nonlinear interaction of photons having OAM and conservation of OAM in nonlinear processes, we experimentally generated ultrafast HGBs of order as high as 6 and power >180 mW at 355 nm. This generic concept can be extended to any wavelength, timescales (continuous-wave and ultrafast) and any orders. We show that the removal of azimuthal phase of vortices does not produce Gaussian beam. We also propose a new and only method to characterize the order of the HGBs. PMID:27581625

  12. High quality beams of MV/cm THz pulses generated from DSTMS

    DEFF Research Database (Denmark)

    Pedersen, Pernille Klarskov; Jepsen, Peter Uhd

    2015-01-01

    A beam characterization of a THz beam generated from the organic crystal DSTMS is presented. The simple, collinear phase-matching geometry for this crystal results in an M2 factor below 1.5, resulting in a focused field strength of more than 4 MV/cm....

  13. Velocity distribution measurements in atomic beams generated using laser induced back-ablation

    CERN Document Server

    Denning, A; Lee, S; Ammonson, M; Bergeson, S D

    2008-01-01

    We present measurements of the velocity distribution of calcium atoms in an atomic beam generated using a dual-stage laser back-ablation apparatus. Distributions are measured using a velocity selective Doppler time-of-flight technique. They are Boltzmann-like with rms velocities corresponding to temperatures above the melting point for calcium. Contrary to a recent report in the literature, this method does not generate a sub-thermal atomic beam.

  14. Generation of slow-positron beams and their applications to surface studies

    International Nuclear Information System (INIS)

    Positron has various unique properties, e.g., positive charge, annihilation with electrons, emission of annihilation gamma ray, positronium formation, etc. These unique properties provides us with new information on surface and subsurface regions. In recent years, generation techniques of intense slow-positron beams have been developed and those beams have been applied to various surface studies. In this article, we briefly introduce slow-positron generation techniques and measurement techniques for surface studies. (author)

  15. Study of Dark-Hollow Beams Generated with Different Multimode Fibres

    Institute of Scientific and Technical Information of China (English)

    ZHAO Cheng-Liang; LU Xuan-Hui; CHEN He

    2008-01-01

    A dark-hollow beam (DHB) is generated by a coupfing of a single fundamental mode He-Ne laser beam with a misalignment multimode fibre (MMF) in a special way.Effects of the misalignment angle,diameter and length of the MMF are studied.The generated DHBs can be used for guiding and trapping of atoms,manipulating particles,or as optical tweezers.

  16. Generation of annular, high-charge electron beams at the Argonne wakefield accelerator

    Science.gov (United States)

    Wisniewski, E. E.; Li, C.; Gai, W.; Power, J.

    2013-01-01

    We present and discuss the results from the experimental generation of high-charge annular(ring-shaped)electron beams at the Argonne Wakefield Accelerator (AWA). These beams were produced by using laser masks to project annular laser profiles of various inner and outer diameters onto the photocathode of an RF gun. The ring beam is accelerated to 15 MeV, then it is imaged by means of solenoid lenses. Transverse profiles are compared for different solenoid settings. Discussion includes a comparison with Parmela simulations, some applications of high-charge ring beams,and an outline of a planned extension of this study.

  17. Generation of High Efficiency Longitudinally Polarized Beam using High NA Lens Axicon and Dedicated Phase Filter

    International Nuclear Information System (INIS)

    We propose to use pure phase filter in combination with high NA lens axicon to achieve high efficient longitudinally polarized beam with a subwavelength spot size and large depth of focus using hyper geometric Gaussian beam. Using this system, the spot size is reduced to 0.392 λ and the depth of focus is increased to 7 λ. The efficiency of such system is found to be 87%. This high efficient longitudinally polarized beam generated by hyper geometric Gaussian beam is useful for most of the near-field optics applications.

  18. Generation of slow muon beam by laser resonant ionization of muonium atoms

    International Nuclear Information System (INIS)

    We report first results of re-acceleration of thermal muons, which were generated by laser resonant ionization of muonium atoms. The re-accelerated beam (slow muon beam) has better energy resolution and space distribution compared to initial surface muon beam, and its use will extend the scope of muon spin relaxation technique from bulk material to thin film, multi-layers, surfaces and extremely small samples. The yield of slow muons obtained during the first beam time was 0.03 muons/s

  19. CERN OVERVIEW animation

    CERN Multimedia

    Arzur Catel Torres

    2015-01-01

    This animation shows how the Large Hadron Collider (LHC) works. The film begins with an aerial view of CERN near Geneva, with outlines of the accelerator complex, including the underground Large Hadron Collider (LHC), 27-km in circumference. The positions of the four largest LHC experiments, ALICE, ATLAS, CMS and LHCb are revealed before we see protons travelling around the LHC ring. The proton source is a simple bottle of hydrogen gas. An electric field is used to strip hydrogen atoms of their electrons to yield protons. Linac 2, the first accelerator in the chain, accelerates the protons to the energy of 50 MeV. The beam is then injected into the Proton Synchrotron Booster (PSB), which accelerates the protons to 1.4 GeV, followed by the Proton Synchrotron (PS), which pushes the beam to 25 GeV. Protons are then sent to the Super Proton Synchrotron (SPS) where they are accelerated to 450 GeV. The protons are finally transferred to the two beam pipes of the LHC. The beam in one pipe circulates clockwise while ...

  20. 2014 CERN Accelerator Schools: Plasma Wake Acceleration

    CERN Multimedia

    2014-01-01

    A specialised school on Plasma Wake Acceleration will be held at CERN, Switzerland from 23-29 November, 2014.   This course will be of interest to staff and students in accelerator laboratories, university departments and companies working in or having an interest in the field of new acceleration techniques. Following introductory lectures on plasma and laser physics, the course will cover the different components of a plasma wake accelerator and plasma beam systems. An overview of the experimental studies, diagnostic tools and state of the art wake acceleration facilities, both present and planned, will complement the theoretical part. Topical seminars and a visit of CERN will complete the programme. Further information can be found at: http://cas.web.cern.ch/cas/PlasmaWake2014/CERN-advert.html http://indico.cern.ch/event/285444/

  1. X-ray generation experiment in STF accelerator on quantum beam technology program

    International Nuclear Information System (INIS)

    To obtain high brightness quasi-monochromatic X-ray via Inverse Compton Scattering, highly intensified laser beam is designed and implemented in a new beam line of KEK Superconducting RF Test Facility (STF) accelerator, under the program of 'Quantum Beam Technology Program'. The STF accelerator is a superconducting Linac using ILC technology, operated with a 5 Hz repetition, 1 ms electron bunch train, and 40 MeV beam energy. The intensified laser beam was generated by a 4-mirror optical cavity with beam-synchronized burst-amplified laser input. The high brightness X-ray is generated by the collision between incoming electron beam and stored laser beam in the 4-mirror cavity. The 4-mirror optical cavity technology has been selected for their stable laser storage with long mirror distance, where electron beam is coming in and out for head-on collision between them. On this report, STF accelerator construction including collision laser system, and also collision results are described. (author)

  2. Workshop on Electron-Cloud Simulations for Proton and Positron Beams (ECLOUD'02) organized by the SL Accelerator Physics Group at CERN.

    CERN Multimedia

    Patrice Loïez

    2002-01-01

    This workshop was organized by the SL Accelerator Physics group at CERN from 15 to 18 April 2002. More than 60 participants from 17 institutes reflect the great worldwide interest in the electron-cloud phenomenon, which presently limits the performance of several storage rings and has become a concern for the LHC.

  3. Self-confinement of a fast pulsed electron beam generated in a double discharge

    Energy Technology Data Exchange (ETDEWEB)

    Goktas, H [Ankara Nuclear Research and Training Center, 06501, Besevler, Ankara (Turkey); Udrea, M [National Institute for Laser, Plasma and Radiation Physics, 76900 Bucharest (Romania); Oke, Gulay [Physics Department, Middle East Technical University, 06531 Ankara (Turkey); Alacakir, A [Ankara Nuclear Research and Training Center, 06501, Besevler, Ankara (Turkey); Demir, A [Physics Department, University of Kocaeli, 41200 Kocaeli (Turkey); Loureiro, J [Centro de Fisica dos Plasmas, Instituto Superior Tecnico, 1049-001 Lisbon (Portugal)

    2005-08-21

    The construction of a double discharge pulsed electron beam generator and the study of the characteristics of the beam are presented in this paper. The electron beam generator consists of a fast filamentary discharge in superposition with an ordinary glow discharge in low-pressure gases. The filling gas is argon or helium at approximately 0.1 Torr pressure. The duration of the electron beam is shorter than 50 ns and the peak current intensity is of the order of amperes. The electron density is evaluated by making use of Stark broadening of the H{sub {beta}} line and compared with the full computer simulation method. The pinch effect of the filamentary discharge is evaluated and its size compared with the diameter of the beam.

  4. Soliton pair generation in the interactions of Airy and nonlinear accelerating beams

    CERN Document Server

    Zhang, Yiqi; Wu, Zhenkun; Zheng, Huaibin; Lu, Keqing; Li, Yuanyuan; Zhang, Yanpeng

    2013-01-01

    We investigate numerically the interactions of two in-phase and out-of-phase Airy beams and nonlinear accelerating beams in Kerr and saturable nonlinear media, in one transverse dimension. We find that bound and unbound soliton pairs, as well as single solitons, can form in such interactions. If the interval between two incident beams is large relative to the width of their first lobes, the generated soliton pairs just propagate individually and do not interact. However, if the interval is comparable to the widths of the maximum lobes, the pairs interact and display varied behavior. In the in-phase case, they attract each other and exhibit stable bound, oscillating, and unbound states, after shedding some radiation initially. In the out-of-phase case, they repel each other and after an initial interaction, fly away as individual solitons. While the incident beams display acceleration, the solitons or soliton pairs generated from those beams do not.

  5. Generation of Terahertz Surface Plasmon Polaritons Using Nondiffractive Bessel Beams with Orbital Angular Momentum.

    Science.gov (United States)

    Knyazev, B A; Choporova, Yu Yu; Mitkov, M S; Pavelyev, V S; Volodkin, B O

    2015-10-16

    Bessel vortex beams with topological charges of l=±1 and l=±2 were produced in the terahertz spectral range from a free electron laser Gaussian beam (λ=141  μm) transformed using silicon binary diffractive optical elements. The spatial characteristics of the beams were obtained using a microbolometer array. A radius to path length ratio of 1:100 was achieved for nondiffractive beams with the average power of 30 W. Surface plasmon polaritons (SPPs) on gold-zinc-sulphide-air interfaces were generated due to diffraction of vortex beams on a sample edge. A new effect, a dependence of the efficiency of SPP generation on the direction of the azimuthal component of incident-radiation Poynting vector, was revealed. PMID:26550877

  6. Underlying conservation and stability laws in nonlinear propagation of axicon-generated Bessel beams

    CERN Document Server

    Porras, Miguel A; Losada, Juan Carlos

    2015-01-01

    In light filamentation induced by axicon-generated, powerful Bessel beams, the spatial propagation dynamics in the nonlinear medium determines the geometry of the filament channel and hence its potential applications. We show that the observed steady and unsteady Bessel beam propagation regimes can be understood in a unified way from the existence of an attractor and its stability properties. The attractor is identified as the nonlinear unbalanced Bessel beam (NL-UBB) whose inward H\\"ankel beam amplitude equals the amplitude of the linear Bessel beam that the axicon would generate in linear propagation. A simple analytical formula that determines de NL-UBB attractor is given. Steady or unsteady propagation depends on whether the attracting NL-UBB has a small, exponentially growing, unstable mode. In case of unsteady propagation, periodic, quasi-periodic or chaotic dynamics after the axicon reproduces similar dynamics after the development of the small unstable mode into the large perturbation regime.

  7. Underlying conservation and stability laws in nonlinear propagation of axicon-generated Bessel beams

    Science.gov (United States)

    Porras, Miguel A.; Ruiz-Jiménez, Carlos; Losada, Juan Carlos

    2015-12-01

    In light filamentation induced by axicon-generated, powerful Bessel beams, the spatial propagation dynamics in the nonlinear medium determines the geometry of the filament channel and hence its potential applications. We show that the observed steady and unsteady Bessel beam propagation regimes can be understood in a unified way from the existence of an attractor and its stability properties. The attractor is identified as the nonlinear unbalanced Bessel beam (NLUBB) whose inward Hänkel beam amplitude equals the amplitude of the linear Bessel beam that the axicon would generate in linear propagation. A simple analytical formula that determines the NLUBB attractor is given. Steady or unsteady propagation depends on whether the attracting NLUBB has a small, exponentially growing, unstable mode. In the case of unsteady propagation, periodic, quasiperiodic, or chaotic dynamics after the axicon reproduces similar dynamics after the development of the small unstable mode into the large perturbation regime.

  8. Efficient yellow beam generation by intracavity sum frequency mixing in DPSS Nd:YVO4 laser

    Indian Academy of Sciences (India)

    A J Singh; P K Gupta; S K Sharma; P K Mukhopadhyay; K S Bindra; S M Oak

    2014-02-01

    We present our studies on dual wavelength operation using a single Nd:YVO4 crystal and its intracavity sum frequency generation by considering the influence of the thermal lensing effect on the performance of the laser. A KTP crystal cut for type-II phase matching was used for intracavity sum frequency generation in the cavity at an appropriate location for efficient and stable yellow output power. More than 550 mW of stable CW yellow-orange beam at 593.5 nm with beam quality parameter (2) ∼ 4.3 was obtained. The total pump to yellow beam conversion efficiency was estimated to be 3.83%.

  9. Beam characterization of a lab bench cold cathode ultra-soft X-ray generator

    OpenAIRE

    Ounoughi, Nabil; Mavon, Christophe; Belafrites, Abdelfettah; Groetz, Jean-Emmanuel; Fromm, Michel

    2013-01-01

    The aim of this work is to characterize the Ultra Soft X-ray (USX, 1.5 keV, Al Kα) photon beam of a customized lab bench cold cathode generator. Within this generator, the electron beam is slowed down in a thin aluminium foil (16 μm) supported by an easily exchangeable anode. It is shown that the thickness of the foil and the anode configuration determine the spatial distribution and the fluence rate of the photon beam, whereas accelerating voltage determines both fluence rate and energy spec...

  10. Generation of electron beams from a laser-based advanced accelerator at Shanghai Jiao Tong University

    CERN Document Server

    Elsied, Ahmed M M; Li, Song; Mirzaie, Mohammad; Sokollik, Thomas; Zhang, Jie

    2014-01-01

    At Shanghai Jiao Tong University, we have established a research laboratory for advanced acceleration research based on high-power lasers and plasma technologies. In a primary experiment based on the laser wakefield acceleration (LWFA) scheme, multi-hundred MeV electron beams having a reasonable quality are generated using 20-40 TW, 30 femtosecond laser pulses interacting independently with helium, neon, nitrogen and argon gas jet targets. The laser-plasma interaction conditions are optimized for stabilizing the electron beam generation from each type of gas. The electron beam pointing angle stability and divergence angle as well as the energy spectra from each gas jet are measured and compared.

  11. Beam conditions for radiation generated by an electromagnetic Hermite-Gaussian model source

    Institute of Scientific and Technical Information of China (English)

    LI Jia; XIN Yu; CHEN Yan-ru

    2011-01-01

    @@ Within the framework of the correlation theory of electromagnetic laser beams, the far field cross-spectral density matrix of the light radiated from an electromagnetic Hermite-Gaussian model source is derived.By utilizing the convergence property of Hermite polynomials, the conditions of the matrices for the source to generate an electromagnetic Hermite-Gaussian beam are obtained.Furthermore, in order to generate a scalar Hermite-Gaussian model beam, it is required that the source should be locally rather coherent in the spatial domain.

  12. Summary report of working group 5: Beam and radiation generation, monitoring, and control

    Energy Technology Data Exchange (ETDEWEB)

    Church, Mike; /Fermilab; Kim, Ki-Yong; /Maryland U.

    2010-01-01

    This paper summarizes the activities and presentations of Working Group 5 of the Advanced Accelerator Concepts Workshop held at Annapolis, Maryland in June 2010. Working Group 5 touched on a broad range of topics in the fields of beam and radiation generation and their monitoring and control. These topics were not comprehensively covered in this Workshop, but rather the Working Group concentrated on specific new developments and recent investigations. The Working Group divided its sessions into four broad categories: cathodes and electron guns, radiation generation, beam diagnostics, and beam control and dynamics. This summary is divided into the same structure.

  13. Generation of equal-intensity coherent optical beams by binary geometrical phase on metasurface

    Science.gov (United States)

    Wang, Zheng-Han; Jiang, Shang-Chi; Xiong, Xiang; Peng, Ru-Wen; Wang, Mu

    2016-06-01

    We report here the design and realization of a broadband, equal-intensity optical beam splitter with a dispersion-free binary geometric phase on a metasurface with unit cell consisting of two mirror-symmetric elements. We demonstrate experimentally that two identical beams can be efficiently generated with incidence of any polarization. The efficiency of the device reaches 80% at 1120 nm and keeps larger than 70% in the range of 1000-1400 nm. We suggest that this approach for generating identical, coherent beams have wide applications in diffraction optics and in entangled photon light source for quantum communication.

  14. Summary report of working group 5: Beam and radiation generation, monitoring, and control

    CERN Document Server

    Church, Mike; 10.1063/1.3520295

    2012-01-01

    This paper summarizes the activities and presentations of Working Group 5 of the Advanced Accelerator Concepts Workshop held at Annapolis, Maryland in June 2010. Working Group 5 touched on a broad range of topics in the fields of beam and radiation generation and their monitoring and control. These topics were not comprehensively covered in this Workshop, but rather the Working Group concentrated on specific new developments and recent investigations. The Working Group divided its sessions into four broad categories: cathodes and electron guns, radiation generation, beam diagnostics, and beam control and dynamics. This summary is divided into the same structure.

  15. Generation of Vortex Beams with Strong Longitudinally Polarized Magnetic Field by Using a Metasurface

    CERN Document Server

    Veysi, Mehdi; Capolino, Filippo

    2014-01-01

    A novel method of generation and synthesis of azimuthally E-polarized vortex beams is presented. Along the axis of propagation such beams have a strong longitudinally polarized magnetic field where ideally there is no electric field. We show how these beams can be constructed through the interference of Laguerre-Gaussian beams carrying orbital angular momentum. As an example, we present a metasurface made of double-split ring slot pairs and report a good agreement between simulated and analytical results. Both a high magnetic-to-electric-field contrast ratio and a magnetic field enhancement are achieved. We also investigate the metasurface physical constraints to convert a linearly polarized beam into an azimuthally E- polarized beam and characterize the performance of magnetic field enhancement and electric field suppression of a realistic metasurface. These findings are potentially useful for novel optical spectroscopy related to magnetic dipolar transitions and for optical manipulation of particles with sp...

  16. Light sources generating self-splitting beams and their propagation in non-Kolmogorov turbulence.

    Science.gov (United States)

    Mei, Zhangrong

    2014-06-01

    A class of random sources producing far fields self-splitting intensity profiles with variable spacing between the x and y directions is introduced. The beam conditions for ensuring the sources to generate a beam are derived. Based on the derived analytical expression, the evolution behavior of the beams produced by these families of sources in free space and turbulence atmospheric are explored and comparatively analyzed. By changing the modulation parameters n and m, the degree of coherence of Gaussian Schell-model source in the x and y directions are modulated respectively, and then the number of splitting beams and the spacing between splitting beams can be adjusted. It is illustrated that the self-splitting intensity profile is stable when beams propagate in free space, but they eventually transformed into a Gaussian profiles when it passes at sufficiently large distances from its source through the turbulent atmosphere.

  17. Self-imaging, self-healing beams generated by photorefractive volume holography

    Science.gov (United States)

    Manigo, Jonathan P.; Guerrero, Raphael A.

    2015-10-01

    Self-imaging beams consisting of three-dimensional intensity voids are generated via photorefractive volume holography. Reconstruction of a volume hologram recorded at 594 nm is performed with a Bessel readout beam. The holographic output is similar in appearance to a Bessel beam, with the central spot oscillating between maximum and zero intensity over a propagation distance of 10 to 55 cm. The oscillation period for the on-axis intensity is 30 cm. The reconstruction is capable of self-healing, with a fully recovered central core after the beam propagates 40 cm. Dual-wavelength reconstruction at 632.8 nm produces an output beam with similar self-imaging and self-healing properties. A theoretical framework based on the interference of a plane wave and a Bessel beam simultaneously reconstructed from a volume hologram is able to describe our experimental results.

  18. Bienvenue au CERN !

    CERN Multimedia

    CERN Press Office. Geneva

    1998-01-01

    CERN, the Laboratory which invented the World-Wide Web has re-invented its public Web site. The new face of CERN has gone live at http://www.cern.ch/ Public . CERN's new Web pages have been designed to give visitors an informative introduction to the fascinating world of particle physics. For those whose whirl around the Web only allows a short stop, there's the 'CERN in two minutes' page.

  19. UK @ CERN

    CERN Multimedia

    FI Department

    2008-01-01

    17 – 18 November 2008 9.00 a.m. - 5.00 p.m. on Monday 17 November 9.00 a.m. - 5.00 p.m. on Tuesday 18 November Individual meetings will take place in the technicians’ or engineers’ offices. The companies will contact relevant users/technicians but anyone wishing to arrange an appointment with a specific company can contact Caroline Laignel (caroline.laignel@cern.ch, tel. 73722). A list of the companies is available from all departmental secretariats and on the web here. List of companies: 1. Caburn MDC Europe Ltd. 2. Croft Engineering Services 3. Cryox Ltd. 4. Goodfellow Cambridge Ltd. 5. Gravatom Engineering Systems Ltd. 6. High Voltage Technology 7. Lilco Ltd. 8. Micro Metalsmiths Ltd. 9. Photek Ltd. 10. Shadow Robot Company 11. Sundance Multiprocessor Technology Ltd. 12. Tessella plc 13. Thermal Resources Management Ltd. 14. Torr Scientific Ltd. For further information please contact Mrs C. Laignel, FI-DI, tel. 73722.

  20. Electron beam generated whistler emissions in a laboratory plasma

    Energy Technology Data Exchange (ETDEWEB)

    Van Compernolle, B., E-mail: bvcomper@physics.ucla.edu; Pribyl, P.; Gekelman, W. [Department of Physics, University of California, Los Angeles (United States); An, X.; Bortnik, J.; Thorne, R. M. [Department of Atmospheric and Oceanic Sciences, University of California, Los Angeles (United States)

    2015-12-10

    Naturally occurring whistler mode emissions in the magnetosphere, are important since they are responsible for the acceleration of outer radiation belt electrons to relativistic energies and also for the scattering loss of these electrons into the atmosphere. Recently, we reported on the first laboratory experiment where whistler waves exhibiting fast frequency chirping have been artificially produced [1]. A beam of energetic electrons is launched into a cold plasma and excites both chirping whistler waves and broadband waves. Here we extend our previous analysis by comparing the properties of the broadband waves with linear theory.

  1. Electron beam generated whistler emissions in a laboratory plasma

    Science.gov (United States)

    Van Compernolle, B.; An, X.; Bortnik, J.; Thorne, R. M.; Pribyl, P.; Gekelman, W.

    2015-12-01

    Naturally occurring whistler mode emissions in the magnetosphere, are important since they are responsible for the acceleration of outer radiation belt electrons to relativistic energies and also for the scattering loss of these electrons into the atmosphere. Recently, we reported on the first laboratory experiment where whistler waves exhibiting fast frequency chirping have been artificially produced [1]. A beam of energetic electrons is launched into a cold plasma and excites both chirping whistler waves and broadband waves. Here we extend our previous analysis by comparing the properties of the broadband waves with linear theory.

  2. Characterization of deuterium beam operation on RHEPP-1 for future neutron generation applications.

    Energy Technology Data Exchange (ETDEWEB)

    Schall, Michael (University of New Mexico, Albuquerque, NM); Cooper, Gary Wayne (University of New Mexico, Albuquerque, NM); Renk, Timothy Jerome

    2009-12-01

    We investigate the potential for neutron generation using the 1 MeV RHEPP-1 intense pulsed ion beam facility at Sandia National Laboratories for a number of emerging applications. Among these are interrogation of cargo for detection of special nuclear materials (SNM). Ions from single-stage sources driven by pulsed power represent a potential source of significant neutron bursts. While a number of applications require higher ion energies (e.g. tens of MeV) than that provided by RHEPP-1, its ability to generate deuterium beams allow for neutron generation at and below 1 MeV. This report details the successful generation and characterization of deuterium ion beams, and their use in generating up to 3 x 10{sup 10} neutrons into 4{pi} per 5kA ion pulse.

  3. Generation of a spin-polarized electron beam by multipole magnetic fields

    Energy Technology Data Exchange (ETDEWEB)

    Karimi, Ebrahim, E-mail: ekarimi@uottawa.ca [Department of Physics, University of Ottawa, 150 Louis Pasteur, Ottawa, Ontario, Canada K1N 6N5 (Canada); Grillo, Vincenzo [CNR-Istituto Nanoscienze, Centro S3, Via G Campi 213/a, I-41125 Modena (Italy); Boyd, Robert W. [Department of Physics, University of Ottawa, 150 Louis Pasteur, Ottawa, Ontario, Canada K1N 6N5 (Canada); Institute of Optics, University of Rochester, Rochester, NY 14627 (United States); Santamato, Enrico [Dipartimento di Scienze Fisiche, Università di Napoli “Federico II”, Compl. Univ. di Monte S. Angelo, 80126 Napoli (Italy); Consorzio Nazionale Interuniversitario per le Scienze Fisiche della Materia, Napoli (Italy)

    2014-03-01

    The propagation of an electron beam in the presence of transverse magnetic fields possessing integer topological charges is presented. The spin–magnetic interaction introduces a nonuniform spin precession of the electrons that gains a space-variant geometrical phase in the transverse plane proportional to the field's topological charge, whose handedness depends on the input electron's spin state. A combination of our proposed device with an electron orbital angular momentum sorter can be utilized as a spin-filter of electron beams in a mid-energy range. We examine these two different configurations of a partial spin-filter generator numerically. The results of this analysis could prove useful in the design of an improved electron microscope. - Highlights: • Theory of generating spin-polarized electron beams. • Interacting electron vortex beams with space-variant magnetic fields. • Bohr–Pauli impossibility of generating spin-polarized free electrons.

  4. Collimated fast electron beam generation in critical density plasma

    International Nuclear Information System (INIS)

    Significantly collimated fast electron beam with a divergence angle 10° (FWHM) is observed when an ultra-intense laser pulse (I = 1014 W/cm2, 300 fs) irradiates a uniform critical density plasma. The uniform plasma is created through the ionization of an ultra-low density (5 mg/c.c.) plastic foam by X-ray burst from the interaction of intense laser (I = 1014 W/cm2, 600 ps) with a thin Cu foil. 2D Particle-In-Cell (PIC) simulation well reproduces the collimated electron beam with a strong magnetic field in the region of the laser pulse propagation. To understand the physical mechanism of the collimation, we calculate energetic electron motion in the magnetic field obtained from the 2D PIC simulation. As the results, the strong magnetic field (300 MG) collimates electrons with energy over a few MeV. This collimation mechanism may attract attention in many applications such as electron acceleration, electron microscope and fast ignition of laser fusion

  5. Collimated fast electron beam generation in critical density plasma

    Energy Technology Data Exchange (ETDEWEB)

    Iwawaki, T., E-mail: iwawaki-t@eie.eng.osaka-u.ac.jp; Habara, H.; Morita, K.; Tanaka, K. A. [Graduate School of Engineering, Osaka University, 2-1, Yamada-oka, Suita, Osaka 565-0871 (Japan); Baton, S.; Fuchs, J.; Chen, S. [LULI, CNRS-Ecole Polytechnique-Université Pierre et Marie Curie-CEA, 91128 Palaiseau (France); Nakatsutsumi, M. [LULI, CNRS-Ecole Polytechnique-Université Pierre et Marie Curie-CEA, 91128 Palaiseau (France); European X-Ray Free-Electron Laser Facility (XFEL) GmbH (Germany); Rousseaux, C. [CEA, DAM, DIF, F-91297 Arpajon (France); Filippi, F. [La SAPIENZA, University of Rome, Dip. SBAI, 00161 Rome (Italy); Nazarov, W. [School of Chemistry, University of St. Andrews, North Haugh, St. Andrews, Fife KY16 9ST, Scotland (United Kingdom)

    2014-11-15

    Significantly collimated fast electron beam with a divergence angle 10° (FWHM) is observed when an ultra-intense laser pulse (I = 10{sup 14 }W/cm{sup 2}, 300 fs) irradiates a uniform critical density plasma. The uniform plasma is created through the ionization of an ultra-low density (5 mg/c.c.) plastic foam by X-ray burst from the interaction of intense laser (I = 10{sup 14 }W/cm{sup 2}, 600 ps) with a thin Cu foil. 2D Particle-In-Cell (PIC) simulation well reproduces the collimated electron beam with a strong magnetic field in the region of the laser pulse propagation. To understand the physical mechanism of the collimation, we calculate energetic electron motion in the magnetic field obtained from the 2D PIC simulation. As the results, the strong magnetic field (300 MG) collimates electrons with energy over a few MeV. This collimation mechanism may attract attention in many applications such as electron acceleration, electron microscope and fast ignition of laser fusion.

  6. Fabrication of Multi-Harmonic Buncher for Pulsed Proton Beam Generation

    Energy Technology Data Exchange (ETDEWEB)

    Kim, H. S.; Kwon, H. J.; Cho, Y. S. [Korea Multipurpose Accelerator Complex, Gyeongju (Korea, Republic of)

    2015-05-15

    Fast neutrons with a broad spectrum can be generated by irradiating the proton beams on target materials. To measure the neutron energy by time of flight (TOF) method, the short pulse width of the proton beam is preferred because the neutron energy uncertainty is proportional to the pulse width. In addition, the pulse repetition rate should be low enough to extend the lower limit of the available neutron energy. Pulsed proton beam generation system is designed based on an electrostatic deflector and slit system as shown in Fig. 1. In a simple deflector with slit system, most of the proton beam is blocked by slit, especially when the beam pulse width is short. The ideal field pattern inside the buncher cavity is saw-tooth wave. To make the field pattern similar to the saw-tooth waveform, we adopted a multi-harmonic buncher (MHB). The design for the multi-harmonic buncher including 3D electromagnetic calculation has been performed. Based on the design, a multi-harmonic buncher cavity was fabricated. It consists of two resonators, two drift tubes and a vacuum chamber. The resonator is a quarter-wave coaxial resonator type. The drift tube is connected to the resonator by using a coaxial vacuum feedthrough. Design summary and detailed fabrication method of the multi-harmonic buncher is presented in this paper. A multi-harmonic buncher for a proton beam chopper system to generate a short pulse neutron beam was designed, fabricated and assembled.

  7. Interference pattern generation and simulation in the single beam of a white light continuum

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    We demonstrate the interference phenomenon in the White Light Continuum(WLC) generated by a single femtosecond laser beam. Different kinds of spatial interference patterns of the WLC generation under various conditions were investigated. The spatial patterns were attributed to interference between the filaments in the WLC generated by the fundamental laser beam yielding the diffraction effect from spatial confinement. Simulations of different patterns were performed. By comparing the results of simulation with those of experiments,the distances of several micrometers between the neighboring filaments can be derived,which agree with the literature values from direct measurements.

  8. Generation of Equal-Energy Orbital Angular Momentum Beams via Photopatterned Liquid Crystals

    Science.gov (United States)

    Chen, Peng; Ge, Shi-Jun; Ma, Ling-Ling; Hu, Wei; Chigrinov, Vladimir; Lu, Yan-Qing

    2016-04-01

    Orbital angular momentum (OAM) has been extensively studied to date and has become topical in the last few years due to its potential for increasing bandwidth in optical communications. The so-called Dammann vortex grating (DVG) can generate a series of equal-energy OAM beams and satisfactorily realize OAM parallel detection, an important challenge in this field. However, previously reported DVGs suffer from polarization sensitivity, low efficiency, or the lack of tunability and mode variety. Here, a design of liquid-crystal DVGs is proposed and demonstrated for the generation of various equal-energy OAM beams. The DVGs, featured by alternative orthogonally planar-aligned regions, are carried out via photopatterning technology. Beam arrays composed of arbitrary OAM modes, as well as two-dimensional ones, are generated in good quality and high efficiency. The liquid-crystal DVGs exhibit merits of excellent polarization independency, electrical switchability, and tunability. This supplies a promising approach towards OAM generation, manipulation, and detection.

  9. SPL and Beta Beams to the Frejus

    CERN Document Server

    Mezzetto, M

    2005-01-01

    Physics potential of a conventional neutrino beam generated by the 2.2 GeV, 4MW, Superconducting Proton Linac and of a Beta Beam fired to a gigantic water Ccaronerenkov detector hosted below Frejus, 130 km away from CERN, are briefly summarized. theta/sub 13/ sensitivity could be improved by up to 3 orders of magnitude with respect to the present experimental limit and a first sensitive search for leptonic CP violation could be performed.

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

    International Nuclear Information System (INIS)

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

  11. Propagation characteristics of Bessel beams generated by continuous, incoherent light sources.

    Science.gov (United States)

    Altıngöz, Ceren; Yalızay, Berna; Akturk, Selcuk

    2015-08-01

    We investigate the propagation behavior of Bessel beams generated by incoherent, continuous light sources. We perform experiments with narrowband and broadband light emitting diodes, and, for comparison, with a laser diode. We observe that the formation of Bessel beams is affected minimally by temporal coherence, while spatial coherence determines the longitudinal evolution of the beam profile. With spatially incoherent beams, the fringe contrast is comparable to the coherent case at the beginning of the Bessel zone, while it completely fades away by propagation, turning into a cylindrical light pipe. Our results show that beam shaping methods can be extended to cases of limited spatial coherence, paving the way for potential new uses and applications of such sources. PMID:26367302

  12. Generation of vector beams using a double-wedge depolarizer: Non-quantum entanglement

    Science.gov (United States)

    Samlan, C. T.; Viswanathan, Nirmal K.

    2016-07-01

    Propagation of horizontally polarized Gaussian beam through a double-wedge depolarizer generates vector beams with spatially varying state of polarization. Jones calculus is used to show that such beams are maximally nonseparable on the basis of even (Gaussian)-odd (Hermite-Gaussian) mode parity and horizontal-vertical polarization state. The maximum nonseparability in the two degrees of freedom of the vector beam at the double wedge depolarizer output is verified experimentally using a modified Sagnac interferometer and linear analyser projected interferograms to measure the concurrence 0.94±0.002 and violation of Clauser-Horne-Shimony-Holt form of Bell-like inequality 2.704±0.024. The investigation is carried out in the context of the use of vector beams for metrological applications.

  13. Generation of arbitrary radially polarized array beams by modulating the correlation structure

    CERN Document Server

    Zhu, Shijun; Li, Zhenhua

    2016-01-01

    We demonstrate a convenient approach for simultaneously manipulating the amplitude and polarization of light beams by means of the modulation of the correlation structure. As an illustration, we constructed a periodic correlation structure that can generate an arbitrary radially polarized array (RPA) beam of a radial or rectangular symmetry array in the focal plane from a radially polarized (RP) beam. The physical realizability conditions for such source and the far-field beam condition are derived. It is illustrated that the beamlet shape and the state of polarization (SOP) can be effectively controlled by the initial correlation structure and the coherence width. Furthermore, by designing the source correlation structure, a tunable OK-shaped RPA beam and an optical cage are demonstrated, which can find widespread applications in non-destructive manipulation of particles and living biological cells. The arbitrariness in the design of correlation structure prompted us to find more convenient approaches for co...

  14. Generation of cylindrically polarized vector vortex beams with digital micromirror device

    Energy Technology Data Exchange (ETDEWEB)

    Gong, Lei; Liu, Weiwei; Wang, Meng; Zhong, Mincheng; Wang, Ziqiang; Li, Yinmei, E-mail: liyinmei@ustc.edu.cn [Department of Optics and Optical Engineering, University of Science and Technology of China, Hefei, Anhui Province 230026 (China); Ren, Yuxuan [National Center for Protein Sciences Shanghai, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, CAS, Shanghai 201210 (China)

    2014-11-14

    We propose a novel technique to directly transform a linearly polarized Gaussian beam into vector-vortex beams with various spatial patterns. Full high-quality control of amplitude and phase is implemented via a Digital Micro-mirror Device (DMD) binary holography for generating Laguerre-Gaussian, Bessel-Gaussian, and helical Mathieu–Gaussian modes, while a radial polarization converter (S-waveplate) is employed to effectively convert the optical vortices into cylindrically polarized vortex beams. Additionally, the generated vector-vortex beams maintain their polarization symmetry after arbitrary polarization manipulation. Due to the high frame rates of DMD, rapid switching among a series of vector modes carrying different orbital angular momenta paves the way for optical microscopy, trapping, and communication.

  15. Terahertz generation by two cross focused Gaussian laser beams in magnetized plasma

    International Nuclear Information System (INIS)

    This paper presents a theoretical model for terahertz (THz) radiation generation by two cross-focused Gaussian laser beams in a collisionless magnetoplasma. The plasma is redistributed due to the ponderomotive nonlinearity which leads to the cross focusing of the laser beams. The focusing of the copropagating laser beams increases with increasing the externally applied static magnetic field which is perpendicular to the wave propagation direction. The nonlinear current at THz frequency arises on account of nonlinear ponderomotive force as a result of beating of the two lasers. The generated THz radiation amplitude increases significantly with increasing magnetic field. The cross focusing of two laser beams enhances the THz yield. Optimization of laser-plasma parameters gives the radiated normalized THz power of the order of 10 kW

  16. Generation of high-power electromagnetic radiation by a beam-driven plasma antenna

    Science.gov (United States)

    Annenkov, V. V.; Volchok, E. P.; Timofeev, I. V.

    2016-04-01

    In this paper we study how efficiently electromagnetic radiation can be generated by a relativistic electron beam with a gigawatt power level during its injection into a thin magnetized plasma. It is shown that, if the transverse beam and plasma size is compared with the radiation wavelength and the plasma density is modulated along the magnetic field, such a beam-plasma system can radiate electromagnetic waves via the antenna mechanism. We propose a theoretical model describing generation of electromagnetic waves by this plasma antenna and calculate its main radiation characteristics. In the two-dimensional case theoretical predictions on the radiation efficiency are shown to be confirmed by the results of particle-in-cell simulations, and the three-dimensional variant of this theory is used to estimate the peak power of sub-terahertz radiation that can be achieved in beam-plasma experiments in mirror traps.

  17. Collimated Blue and Infrared Beams Generated by Two-Photon Excitation in Rubidium Vapor

    Science.gov (United States)

    Gearba, Alina; Sell, Jerry; Olesen, Robert; Knize, Randy

    2016-05-01

    Utilizing nonlinear optical processes in Rb vapor we describe the generation of optical fields at 420 nm, 1.32 μm, and 1.37 μm. Input laser beams at 780 nm and 776 nm enter a heated Rb vapor cell collinear and circularly polarized. Rubidium atoms are excited to the 5D5 / 2 state, with blue light generated by four-wave mixing through the 6P3 / 2 --> 5S1 / 2 states, while infrared beams at 1.37 μm and 1.32 μm are generated by cascading decays through the 6S1 / 2 --> 5P3 / 2 and 6S1 / 2 --> 5P1 / 2 states, respectively. While the blue beam emission from four-wave mixing has been studied in detail, the mechanisms responsible for generating the infrared beams are still under investigation. We will present our results for the conditions which give rise to infrared beam generation by two-photon excitation in rubidium vapor.

  18. High School Teachers at CERN

    CERN Multimedia

    Anna Pantelia

    2012-01-01

    Now in its 15th consecutive year, CERN's High School Teachers (HST) Programme continues to bring secondary school physics teachers from member and non-member states to CERN to update their knowledge of particle physics and inspire the next generation of scientists. During this 3-week residential course, participants attend lectures and workshops, visit experimental facilities and create new teaching resources in a truly collaborative and international atmosphere. This video documents the experiences of some of the 42 participants of the HST 2012 Programme, which has been marked by the July 4th Seminar on Higgs.

  19. Characterization of excitation beam on second-harmonic generation in fibrillous type I collagen

    OpenAIRE

    Chang, Ying; Deng, Xiaoyuan

    2010-01-01

    Following our established theoretical model to deal with the second-harmonic generation (SHG) excited by a linearly polarized focused beam in type I collagen, in this paper, we further quantitatively characterize the differences between SHG emissions in type I collagen excited by collimated and focused beams. The effects of the linear polarization angle (α) and the fibril polarity characterized by the hyperpolarizability ratio ρ on SHG emission has been compared under collimated and focused b...

  20. Generation of J0 Bessel Beams with controlled spatial coherence features

    OpenAIRE

    Carbajal-Dominguez, Adrian; Bernal, Jorge; Martin-Ruiz, Alberto; Niconoff, Gabriel Martínez

    2010-01-01

    An alternative method to generate J0 Bessel beams with controlled spatial partial coherence properties is introduced. Far field diffraction from a discrete number of source points on an annular region is calculated. The average for different diffracted fields produced at several rotation angles is numerically calculated and experimentally detected. Theoretical and experimental results show that for this particular case, J0 Bessel beam is a limit when the number of points tends towards infinit...

  1. Second-harmonic generation in shear wave beams with different polarizations

    International Nuclear Information System (INIS)

    A coupled pair of nonlinear parabolic equations was derived by Zabolotskaya [1] that model the transverse components of the particle motion in a collimated shear wave beam propagating in an isotropic elastic solid. Like the KZK equation, the parabolic equation for shear wave beams accounts consistently for the leading order effects of diffraction, viscosity and nonlinearity. The nonlinearity includes a cubic nonlinear term that is equivalent to that present in plane shear waves, as well as a quadratic nonlinear term that is unique to diffracting beams. The work by Wochner et al. [2] considered shear wave beams with translational polarizations (linear, circular and elliptical), wherein second-order nonlinear effects vanish and the leading order nonlinear effect is third-harmonic generation by the cubic nonlinearity. The purpose of the current work is to investigate the quadratic nonlinear term present in the parabolic equation for shear wave beams by considering second-harmonic generation in Gaussian beams as a second-order nonlinear effect using standard perturbation theory. In order for second-order nonlinear effects to be present, a broader class of source polarizations must be considered that includes not only the familiar translational polarizations, but also polarizations accounting for stretching, shearing and rotation of the source plane. It is found that the polarization of the second harmonic generated by the quadratic nonlinearity is not necessarily the same as the polarization of the source-frequency beam, and we are able to derive a general analytic solution for second-harmonic generation from a Gaussian source condition that gives explicitly the relationship between the polarization of the source-frequency beam and the polarization of the second harmonic

  2. Second-harmonic generation in shear wave beams with different polarizations

    Energy Technology Data Exchange (ETDEWEB)

    Spratt, Kyle S., E-mail: sprattkyle@gmail.com; Ilinskii, Yurii A.; Zabolotskaya, Evgenia A.; Hamilton, Mark F. [Applied Research Laboratories, The University of Texas at Austin, P. O. Box 8029, Austin, Texas 78713–8029, US (United States)

    2015-10-28

    A coupled pair of nonlinear parabolic equations was derived by Zabolotskaya [1] that model the transverse components of the particle motion in a collimated shear wave beam propagating in an isotropic elastic solid. Like the KZK equation, the parabolic equation for shear wave beams accounts consistently for the leading order effects of diffraction, viscosity and nonlinearity. The nonlinearity includes a cubic nonlinear term that is equivalent to that present in plane shear waves, as well as a quadratic nonlinear term that is unique to diffracting beams. The work by Wochner et al. [2] considered shear wave beams with translational polarizations (linear, circular and elliptical), wherein second-order nonlinear effects vanish and the leading order nonlinear effect is third-harmonic generation by the cubic nonlinearity. The purpose of the current work is to investigate the quadratic nonlinear term present in the parabolic equation for shear wave beams by considering second-harmonic generation in Gaussian beams as a second-order nonlinear effect using standard perturbation theory. In order for second-order nonlinear effects to be present, a broader class of source polarizations must be considered that includes not only the familiar translational polarizations, but also polarizations accounting for stretching, shearing and rotation of the source plane. It is found that the polarization of the second harmonic generated by the quadratic nonlinearity is not necessarily the same as the polarization of the source-frequency beam, and we are able to derive a general analytic solution for second-harmonic generation from a Gaussian source condition that gives explicitly the relationship between the polarization of the source-frequency beam and the polarization of the second harmonic.

  3. Investigation of the influence of extra noises in seed beams on continuous-variable entanglement generation

    Institute of Scientific and Technical Information of China (English)

    Shang Ya-Na; Yan Zhi-Hui; Jia Xiao-Jun; Su Xiao-Long; Xie Chang-De

    2011-01-01

    The influence of the extra classical noises in seed beams on the entanglement between the signal and the idler modes of the output fields generated by a non-degenerate optical parametric amplifier operating at deamplification is investigated theoretically and experimentally. With the increase of the extra classical noises in the seed beams, the correlation degree of the output entangled optical fields, which is scaled by the quantum noise limit, decreases rapidly. The experimental results are in good agreement with the theoretical calculations.

  4. Photopolymerized microscopic vortex beam generators: Precise delivery of optical orbital angular momentum

    OpenAIRE

    Brasselet, Etienne; Malinauskas, Mangirdas; Žukauskas, Albertas; Juodkazis, Saulius

    2010-01-01

    International audience Direct femtosecond laser photopolymerization is used to fabricate high resolution microscopic spiral phase plates. The total phase change all around their center is prepared to be a integer multiple of 2(pi) for the operating wavelength in the visible domain. The optical performances of the spiral plates are measured and we propose a simple single beam interferometric technique to characterize the phase singularity of the generated vortex beams. The experimental resu...

  5. Low emittance pion beams generation from bright photons and relativistic protons

    CERN Document Server

    Serafini, L; Petrillo, V

    2015-01-01

    Present availability of high brilliance photon beams as those produced by X-ray Free Electron Lasers in combination with intense TeV proton beams typical of the Large Hadron Collider makes it possible to conceive the generation of pion beams via photo-production in a highly relativistic Lorentz boosted frame: the main advantage is the low emittance attainable and a TeV-class energy for the generated pions, that may be an interesting option for the production of low emittance muon and neutrino beams. We will describe the kinematics of the two classes of dominant events, i.e. the pion photo-production and the electron/positron pair production, neglecting other small cross-section possible events like Compton and muon pair production. Based on the phase space distributions of the pion and muon beams we will analyze the pion beam brightness achievable in three examples, based on advanced high efficiency high repetition rate FELs coupled to LHC or Future Circular Collider (FCC) proton beams, together with the stud...

  6. Generation of oxygen, carbon and metallic ion beams by a compact microwave source

    International Nuclear Information System (INIS)

    A small microwave ion source fabricated from a quartz tube and enclosed externally by a cavity has been operated with different geometries and for various gases in a cw mode. This source has been used to generate oxygen ion beams with energy as low as 5.5 eV. Beam energy spread has been measured to be less than 1 eV. By installing different metal plates on the front extraction electrode, metallic ion beams such as (Be, Cu, Al, etc.) can be produced

  7. Advanced Electron Beam Ion Sources (EBIS) for 2-nd generation carbon radiotherapy facilities

    International Nuclear Information System (INIS)

    In this work we analyze how advanced Electron Beam Ion Sources (EBIS) can facilitate the progress of carbon therapy facilities. We will demonstrate that advanced ion sources enable operation of 2-nd generation ion beam therapy (IBT) accelerators. These new accelerator concepts with designs dedicated to IBT provide beams better suited for therapy and, are more cost efficient than contemporary IBT facilities. We will give a sort overview of the existing new IBT concepts and focus on those where ion source technology is the limiting factor. We will analyse whether this limitation can be overcome in the near future thanks to ongoing EBIS development

  8. Generation of radially polarized beam with a segmented spiral varying retarder.

    Science.gov (United States)

    Lai, W J; Lim, B C; Phua, P B; Tiaw, K S; Teo, H H; Hong, M H

    2008-09-29

    We convert a linearly polarized Gaussian beam into a radially polarized doughnut beam with an eight-segment spirally varying retarder (SVR) at wavelength of 808 nm. The SVR is designed based on the linear birefringence of alpha-barium borate (alpha-BBO) crystal and fabricated using a dry etching process. Radially polarized light of high purity (> 96% at far-field distribution) was generated experimentally using the segmented SVR positioned between two quarter waveplates with orthogonal slow axes. The emergent polarization can be switched between radially and azimuthally polarized cylindrical vector beams with a pair of half-wave plates.

  9. Generation of radially polarized beam with a segmented spiral varying retarder.

    Science.gov (United States)

    Lai, W J; Lim, B C; Phua, P B; Tiaw, K S; Teo, H H; Hong, M H

    2008-09-29

    We convert a linearly polarized Gaussian beam into a radially polarized doughnut beam with an eight-segment spirally varying retarder (SVR) at wavelength of 808 nm. The SVR is designed based on the linear birefringence of alpha-barium borate (alpha-BBO) crystal and fabricated using a dry etching process. Radially polarized light of high purity (> 96% at far-field distribution) was generated experimentally using the segmented SVR positioned between two quarter waveplates with orthogonal slow axes. The emergent polarization can be switched between radially and azimuthally polarized cylindrical vector beams with a pair of half-wave plates. PMID:18825207

  10. CERN openlab enters new phase

    CERN Multimedia

    Katarina Anthony

    2012-01-01

    The newest phase of CERN’s openlab framework was inaugurated this week during a meeting of the openlab partners. This phase will last three years and will bring together existing openlab partners and a new contributor: Huawei.   Group picture taken at the first CERN openlab IV annual Board of Sponsors meeting, in the presence of the CERN Director-General, the partners and the openlab team members. © Fons Rademakers (CERN Photo Club). Eleven years ago, the creation of the CERN openlab created a long-term link between industrial partners and the Organization. Its framework has allowed industry to carry out large-scale IT research and development in an open atmosphere – an “Open Lab”, if you will. For CERN, openlab has contributed to giving the computing centre and, more broadly, the LHC community, the opportunity to ensure that the next generation of services and products is suitable to their needs. Now entering its fourth phase, openlab will ...

  11. Hangout with CERN: Welcome to CERN (S01E01)

    CERN Multimedia

    Kahle, Kate

    2012-01-01

    In this first Hangout with CERN "Welcome to CERN" ATLAS physicist Steven Goldfarb, CERN theorist Alvaro De Rujula and Mick Storr from the CERN education group introduce CERN and answer some of the questions received via #askCERN on Twitter and Google+. Recorded live on 1st November 2012.

  12. The Evolution of CERN EDMS

    CERN Document Server

    Wardzinska, Aleksandra; Bray, Rachel; Delamare, Christophe; Arza, Griselda Garcia; Krastev, Tsvetelin; Pater, Krzysztof; Suwalska, Anna; Widegren, David

    2015-01-01

    Large-scale long-term projects such as the LHC require the ability to store, manage, organize and distribute large amounts of engineering information, covering a wide spectrum of fields. This information is a living material, evolving in time, following specific lifecycles. It has to reach the next generations of engineers so they understand how their predecessors designed, crafted, operated and maintained the most complex machines ever built.This is the role of CERN EDMS. The Engineering and Equipment Data Management Service has served the High Energy Physics Community for over 15 years. It is CERN's official PLM (Product Lifecycle Management), supporting engineering communities in their collaborations inside and outside the laboratory. EDMS is integrated with the CAD (Computer-aided Design) and CMMS (Computerized Maintenance Management) systems used at CERN providing tools for engineers who work in different domains and who are not PLM specialists.Over the years, human collaborations and machines grew in si...

  13. 32 nm imprint masks using variable shape beam pattern generators

    Science.gov (United States)

    Selinidis, Kosta; Thompson, Ecron; Schmid, Gerard; Stacey, Nick; Perez, Joseph; Maltabes, John; Resnick, Douglas J.; Yeo, Jeongho; Kim, Hoyeon; Eynon, Ben

    2008-05-01

    Imprint lithography has been included on the ITRS Lithography Roadmap at the 32, 22 and 16 nm nodes. Step and Flash Imprint Lithography (S-FIL ®) is a unique method that has been designed from the beginning to enable precise overlay for creating multilevel devices. A photocurable low viscosity monomer is dispensed dropwise to meet the pattern density requirements of the device, thus enabling imprint patterning with a uniform residual layer across a field and across entire wafers. Further, S-FIL provides sub-100 nm feature resolution without the significant expense of multi-element, high quality projection optics or advanced illumination sources. However, since the technology is 1X, it is critical to address the infrastructure associated with the fabrication of templates. For sub-32 nm device manufacturing, one of the major technical challenges remains the fabrication of full-field 1x templates with commercially viable write times. Recent progress in the writing of sub-40 nm patterns using commercial variable shape e-beam tools and non-chemically amplified resists has demonstrated a very promising route to realizing these objectives, and in doing so, has considerably strengthened imprint lithography as a competitive manufacturing technology for the sub 32nm node. Here we report the first imprinting results from sub-40 nm full-field patterns, using Samsung's current flash memory production device design. The fabrication of the template is discussed and the resulting critical dimension control and uniformity are discussed, along with image placement results. The imprinting results are described in terms of CD uniformity, etch results, and overlay.

  14. The COMPASS Experiment at CERN

    CERN Document Server

    Abbon, P.; Alexakhin, V.Yu.; Alexandrov, Yu.; Alexeev, G.D.; Alekseev, M.G.; Amoroso, A.; Angerer, H.; Anosov, V.A.; Badelek, B.; Balestra, F.; Ball, J.; Barth, J.; Baum, G.; Becker, M.; Bedfer, Y.; Berglund, P.; Bernet, C.; Bertini, R.; Bettinelli, M.; Birsa, R.; Bisplinghoff, J.; Bordalo, P.; Bosteels, M.; Bradamante, F.; Braem, A.; Bravar, A.; Bressan, A.; Brona, G.; Burtin, E.; Bussa, M.P.; Bytchkov, V.N.; Chalifour, M.; Chapiro, A.; Chiosso, M.; Ciliberti, P.; Cicuttin, A.; Colantoni, M.; Colavita, A.A.; Costa, S.; Crespo, M.L.; Cristaudo, P.; Dafni, T.; d'Hose, N.; Dalla Torre, S.; d'Ambrosio, C.; Das, S.; Dasgupta, S.S.; Delagnes, E.; De Masi, R.; Deck, P.; Dedek, N.; Demchenko, D.; Denisov, O.Yu.; Dhara, L.; Diaz, V.; Dibiase, N.; Dinkelbach, A.M.; Dolgopolov, A.V.; Donati, A.; Donskov, S.V.; Dorofeev, V.A.; Doshita, N.; Durand, D.; Duic, V.; Dunnweber, W.; Efremov, A.; Eversheim, P.D.; Eyrich, W.; Faessler, M.; Falaleev, V.; Fauland, P.; Ferrero, A.; Ferrero, L.; Finger, M.; Finger, M.; Fischer, H.; Franco, C.; Franz, J.; Fratnik, F.; Friedrich, J.M.; Frolov, V.; Fuchs, U.; Garfagnini, R.; Gatignon, L.; Gautheron, F.; Gavrichtchouk, O.P.; Gerassimov, S.; Geyer, R.; Gheller, J.M.; Giganon, A.; Giorgi, M.; Gobbo, B.; Goertz, S.; Gorin, A.M.; Gougnaud, F.; Grabmuller, S.; Grajek, O.A.; Grasso, A.; Grube, B.; Grunemaier, A.; Guskov, A.; Haas, F.; Hagemann, R.; Hannappel, J.; von Harrach, D.; Hasegawa, T.; Heckmann, J.; Hedicke, S.; Heinsius, F.H.; Hermann, R.; Hess, C.; Hinterberger, F.; von Hodenberg, M.; Horikawa, N.; Horikawa, S.; Horn, I.; Ilgner, C.; Ioukaev, A.I.; Ishimoto, S.; Ivanchin, I.; Ivanov, O.; Iwata, T.; Jahn, R.; Janata, A.; Joosten, R.; Jouravlev, N.I.; Kabuss, E.; Kalinnikov, V.; Kang, D.; Karstens, F.; Kastaun, W.; Ketzer, B.; Khaustov, G.V.; Khokhlov, Yu.A.; Kiefer, J.; Kisselev, Yu.; Klein, F.; Klimaszewski, K.; Koblitz, S.; Koivuniemi, J.H.; Kolosov, V.N.; Komissarov, E.V.; Kondo, K.; Konigsmann, Kay; Konoplyannikov, A.K.; Konorov, I.; Konstantinov, V.F.; Korentchenko, A.S.; Korzenev, A.; Kotzinian, A.M.; Koutchinski, N.A.; Kouznetsov, O.; Kowalik, K.; Kramer, D.; Kravchuk, N.P.; Krivokhizhin, G.V.; Kroumchtein, Z.V.; Kubart, J.; Kuhn, R.; Kukhtin, V.; Kunne, F.; Kurek, K.; Kuzmin, N.A.; Lamanna, M.; Le Goff, J.M.; Leberig, M.; Lednev, A.A.; Lehmann, A.; Levinski, V.; Levorato, S.; Lyashenko, V.I; Lichtenstadt, J.; Liska, T.; Ludwig, I.; Maggiora, A.; Maggiora, M.; Magnon, A.; Mallot, G.K.; Mann, A.; Manuilov, I.V.; Marchand, C.; Marroncle, J.; Martin, A.; Marzec, J.; Masek, L.; Massmann, F.; Matsuda, T.; Matthia, D.; Maximov, A.N.; Menon, G.; Meyer, W.; Mielech, A.; Mikhailov, Yu.V.; Moinester, M.A.; Molinie, F.; Mota, F.; Mutter, A.; Nagel, T.; Nahle, O.; Nassalski, J.; Neliba, S.; Nerling, F.; Neyret, D.; Niebuhr, M.; Niinikoski, T.; Nikolaenko, V.I.; Nozdrin, A.A.; Olshevsky, A.G.; Ostrick, M.; Padee, A.; Pagano, P.; Panebianco, S.; Parsamyan, B.; Panzieri, D.; Paul, S.; Pawlukiewicz, B.; Pereira, H.; Peshekhonov, D.V.; Peshekhonov, V.D.; Piedigrossi, D.; Piragino, G.; Platchkov, S.; Platzer, K.; Pochodzalla, J.; Polak, J.; Polyakov, V.A.; Pontecorvo, G.; Popov, A.A.; Pretz, J.; Procureur, S.; Quintans, C.; Rajotte, J.-F.; Ramos, S.; Razaq, I.; Rebourgeard, P.; Reggiani, D.; Reicherz, G.; Richter, A.; Robinet, F.; Rocco, E.; Rondio, E.; Ropelewski, L.; Rousse, J.Y.; Rozhdestvensky, A.M.; Ryabchikov, D.; Samartsev, A.G.; Samoylenko, V.D.; Sandacz, A.; Merce, M.Sans; Santos, H.; Sapozhnikov, M.G.; Sauli, F.; Savin, Igor A.; Schiavon, P.; Schill, C.; Schmidt, T.; Schmitt, H.; Schmitt, L.; Schonmeier, P.; Schroeder, W.; Seeharsch, D.; Seimetz, M.; Setter, D.; Shaligin, A.; Shevchenko, O.Yu.; Shishkin, A.A.; Siebert, H.-W.; Silva, L.; Simon, F.; Sinha, L.; Sissakian, A.N.; Slunecka, M.; Smirnov, G.I.; Sora, D.; Sosio, S.; Sozzi, F.; Srnka, A.; Stinzing, F.; Stolarski, M.; Sugonyaev, V.P.; Sulc, M.; Sulej, R.; Tarte, G.; Takabayashi, N.; Tchalishev, V.V.; Tessaro, S.; Tessarotto, F.; Teufel, A.; Thers, D.; Tkatchev, L.G.; Toeda, T.; Tokmenin, V.V.; Trippel, S.; Urban, J.; Valbuena, R.; Venugopal, G.; Virius, M.; Vlassov, N.V.; Vossen, A.; Wagner, M.; Webb, R.; Weise, E.; Weitzel, Q.; Wiedner, U.; Wiesmann, M.; Windmolders, R.; Wirth, S.; Wislicki, W.; Wollny, H.; Zanetti, A.M.; Zaremba, K.; Zavertyaev, M.; Zhao, J.; Ziegler, R.; Ziembicki, M.; Zlobin, Y.L.; Zvyagin, A.

    2007-01-01

    The COMPASS experiment makes use of the CERN SPS high-intensitymuon and hadron beams for the investigation of the nucleon spin structure and the spectroscopy of hadrons. One or more outgoing particles are detected in coincidence with the incoming muon or hadron. A large polarized target inside a superconducting solenoid is used for the measurements with the muon beam. Outgoing particles are detected by a two-stage, large angle and large momentum range spectrometer. The setup is built using several types of tracking detectors, according to the expected incident rate, required space resolution and the solid angle to be covered. Particle identification is achieved using a RICH counter and both hadron and electromagnetic calorimeters. The setup has been successfully operated from 2002 onwards using a muon beam. Data with a hadron beam were also collected in 2004. This article describes the main features and performances of the spectrometer in 2004; a short summary of the 2006 upgrade is also given.

  15. Doing business with CERN

    CERN Multimedia

    2015-01-01

    The Procurement Service, in collaboration with the Communications group’s Design team, has recently launched a new information campaign targeted at companies wishing to supply their products and services to CERN. This campaign comprises:   A brochure, available in hard and soft copy:  http://procurement.web.cern.ch/brochures/doing-business-with-cern.   A 6-minute video overview: https://procurement-dev.web.cern.ch/doing-business-with-cern. This campaign is intended for Member State firms with whom CERN is yet to do business. The key objectives are: To emphasise that CERN can be considered a major customer across a wide range of activities;   To present CERN’s procurement procedures in a dynamic and digestible way;   To highlight the information available on CERN’s procurement website: http://procurement.web.cern.ch. Furthermore, a new section called “Having a contract with CERN” is also now ava...

  16. Virgin Galactic explores CERN

    CERN Multimedia

    2016-01-01

    Virgin Galactic visited CERN with a group of future astronauts and Sir Richard Branson. During their visit the group was shown around various experiments, including the Globe, SM18, AMS and the CERN Control Centre.

  17. CERN Shop Christmas Sale

    CERN Multimedia

    Visits & Exhibition Service/ETT-VE

    2001-01-01

    11-13.12.2001 Looking for Christmas present ideas? Come to the Reception Shop Special Stand in Meyrin, Main Building, ground floor, from Tuesday 11 to Thursday 13 December from 10.30 to 16.00. CERN Calendar 10.- CERN Sweat-shirts(M, L, XL) 30.- CERN T-shirt (M, L, XL) 20.- New CERN silk tie (2 colours) 35.- Fancy silk tie (blue, bordeau) 25.- Silk scarf (light blue, red, yellow) 35.- Swiss army knife with CERN logo 25.- CERN watch 25.- CERN baseball cap 15.- CERN briefcase 15.- Book 'Antimatter' (English) 35.- Book 'How the web was born' (English) 25.- The Search for Infinity (French, Italian, English, German) 40.-   If you miss this special occasion, the articles are also available at the Reception Shop in Building 33 from Monday to Saturday between 08.30 and 17.30 hrs.

  18. Fault detection on the Large Hadron Collider at CERN: design, simulation and realization of a High Voltage Pulse Generator

    CERN Document Server

    Cavicchioli, C; Biagi, E; Bozzini, D

    2007-01-01

    This project was developed inside the Quality Assurance Plan (ELQA) of the LHC. The superconducting circuits of the collider show a great complexity concerning the control system, because of various reasons: the tunnel is placed around 50 to 175 m underground, the circuits work at temperatures of 1.9 K, all the structure should be perfectly aligned and the electronic part has considerable dimensions. To maximize the running time of the collider, it is necessary to develop methods for the diagnostic of defects and for the precise localization of the segment of the accelerator that contains the fault. From my studies it emerged that a possible way to localize electrical faults in the LHC superconducting circuits is to combine the use of time domain reflectometry methods and high voltage pulses. Therefore, I have designed and realized a high voltage pulse generator that will be an important instrument for the fault location among the accelerator.

  19. Effect of transverse magnetic field on generation of electron beam in gas diode

    International Nuclear Information System (INIS)

    One studied experimentally the effect of the transverse magnetic field (0.08 and 0.016 T) on the generation of an electron beam within a gas diode. At U=25 kV gas diode voltage and helium low pressure (45 Torr) the transverse magnetic field is shown to affect the beam current amplitude outside the foil and on its foil cross section distribution. Under the increased pressure values and at generation of an ultra short-time avalanche electron beam (UAEB) in helium, nitrogen and in air the transverse magnetic field is shown to affect negligibly the UAEB amplitude and duration outside the foil. At the generator voltage equal to hundreds of kilovolts a portion of the escaping electrons was found to arrive to the gas diode lateral walls including those from the discharge plasma in the vicinity of a cathode

  20. Soliton generation by internal tidal beams impinging on a pycnocline: laboratory experiments

    CERN Document Server

    Mercier, Matthieu J; Gostiaux, Louis; Gerkema, Theo; Magalhães, Jorge M; Da Silva, José C B; Dauxois, Thierry

    2015-01-01

    In this paper, we present the first laboratory experiments that show the generation of internal solitary waves by the impingement of a quasi-two-dimensional internal wave beam on a pycnocline. These experiments were inspired by observations of internal solitary waves in the deep ocean from synthetic aperture radar (SAR) imagery, where this so-called mechanism of 'local generation' was argued to be at work, here in the form of internal tidal beams hitting the thermocline. Nonlinear processes involved here are found to be of two kinds. First, we observe the generation of a mean flow and higher harmonics at the location where the principal beam reflects from the surface and pycnocline; their characteristics are examined using particle image velocimetry (PIV) measurements. Second, we observe internal solitary waves that appear in the pycnocline, detected with ultrasonic probes; they are further characterized by a bulge in the frequency spectrum, distinct from the higher harmonics. Finally, the relevance of our re...

  1. Parameters of a supershort avalanche electron beam generated in atmospheric-pressure air

    International Nuclear Information System (INIS)

    Conditions under which the number of runaway electrons in atmospheric-pressure air reaches ∼5 × 1010 are determined. Recommendations for creating runaway electron accelerators are given. Methods for measuring the parameters of a supershort avalanche electron beam and X-ray pulses from gas-filled diodes, as well as the discharge current and gap voltage, are described. A technique for determining the instant of runaway electron generation with respect to the voltage pulse is proposed. It is shown that the reduction in the gap voltage and the decrease in the beam current coincide in time. The mechanism of intense electron beam generation in gas-filled diodes is analyzed. It is confirmed experimentally that, in optimal regimes, the number of electrons generated in atmospheric-pressure air with energies T > eUm, where Um is the maximum gap voltage, is relatively small.

  2. Parameters of a supershort avalanche electron beam generated in atmospheric-pressure air

    Science.gov (United States)

    Tarasenko, V. F.

    2011-05-01

    Conditions under which the number of runaway electrons in atmospheric-pressure air reaches ˜5 × 1010 are determined. Recommendations for creating runaway electron accelerators are given. Methods for measuring the parameters of a supershort avalanche electron beam and X-ray pulses from gas-filled diodes, as well as the discharge current and gap voltage, are described. A technique for determining the instant of runaway electron generation with respect to the voltage pulse is proposed. It is shown that the reduction in the gap voltage and the decrease in the beam current coincide in time. The mechanism of intense electron beam generation in gas-filled diodes is analyzed. It is confirmed experimentally that, in optimal regimes, the number of electrons generated in atmospheric-pressure air with energies T > eU m , where U m is the maximum gap voltage, is relatively small.

  3. Experimental characterization of quantum correlated triple beams generated by cascaded four-wave mixing processes

    Energy Technology Data Exchange (ETDEWEB)

    Qin, Zhongzhong; Cao, Leiming; Jing, Jietai, E-mail: jtjing@phy.ecnu.edu.cn [State Key Laboratory of Precision Spectroscopy, Department of Physics, East China Normal University, Shanghai 200062 (China)

    2015-05-25

    Quantum correlations and entanglement shared among multiple modes are fundamental ingredients of most continuous-variable quantum technologies. Recently, a method used to generate multiple quantum correlated beams using cascaded four-wave mixing (FWM) processes was theoretically proposed and experimentally realized by our group [Z. Qin et al., Phys. Rev. Lett. 113, 023602 (2014)]. Our study of triple-beam quantum correlation paves the way to showing the tripartite entanglement in our system. Our system also promises to find applications in quantum information and precision measurement such as the controlled quantum communications, the generation of multiple quantum correlated images, and the realization of a multiport nonlinear interferometer. For its applications, the degree of quantum correlation is a crucial figure of merit. In this letter, we experimentally study how various parameters, such as the cell temperatures, one-photon, and two-photon detunings, influence the degree of quantum correlation between the triple beams generated from the cascaded two-FWM configuration.

  4. Greece at CERN

    CERN Multimedia

    CERN Press Office. Geneva

    1997-01-01

    Greece, one of CERN*'s founding Member States, inaugurated its first Industrial Exhibition at the Meyrin site on Tuesday, 14 October. After a meeting with CERN's Director General, Professor Christopher Llewellyn Smith, Professor Emmanuel Frangoulis, the General Secretary of the Greek Ministry of Industry, accompanied by Prof Emmanuel Floratos, Greek delegate to CERN council visited the DELPHI experiment on the LEP collider, guided by Andromachi Tsirou, a Greek physicist.

  5. France at CERN

    CERN Multimedia

    CERN Bulletin

    2010-01-01

    Rolf Heuer, CERN Director General, visits the exhibition "La France au CERN". The exhibition France at CERN, organized by UBIFRANCE in collaboration with CERN's GS/SEM (Site Engineering and Management) service, took place from Monday 7 to Wednesday 9 June in the Main Building. The 36 French firms taking part came to present their products and technologies related to the Organization's activities. The next exhibition will be "Netherlands at CERN" in November.

  6. The CERN Library

    CERN Multimedia

    Hester, Alec G

    1968-01-01

    Any advanced research centre needs a good Library. It can be regarded as a piece of equipment as vital as any machine. At the present time, the CERN Library is undergoing a number of modifications to adjust it to the changing scale of CERN's activities and to the ever increasing flood of information. This article, by A.G. Hester, former Editor of CERN COURIER who now works in the Scientific Information Service, describes the purposes, methods and future of the CERN Library.

  7. Beam characterization of a lab bench cold cathode ultra-soft X-ray generator

    Science.gov (United States)

    Ounoughi, N.; Mavon, C.; Belafrites, A.; Groetz, J.-E.; Fromm, M.

    2013-06-01

    The aim of this work is to characterize the Ultra Soft X-ray (USX, 1.5 keV, Al Kα) photon beam of a customized lab bench cold cathode generator. Within this generator, the electron beam is slowed down in a thin aluminium foil (16 μm) supported by an easily exchangeable anode. It is shown that the thickness of the foil and the anode configuration determine the spatial distribution and the fluence rate of the photon beam, whereas accelerating voltage determines both fluence rate and energy spectrum feature. It is shown also that under specific operation parameters (i.e. accelerating voltage), a Gaussian energy distribution of the beam can be generated which is centred on the energy of the Al Kα line (1.5 keV). Dosimetric films of GAFCHROMIC® HD-810 were used to estimate the photon fluence rate distribution of the beam. Its variation, when the generator acts as a monoenergetic source, was characterized with the two different configurations of the anode assembly. Finally, it is verified that the anode assembly consisting in a flat washer, on which the aluminium foil is set, acts as a simple point-source.

  8. Generation of tubular beams of negative hydrogen ions by a surface plasma source

    International Nuclear Information System (INIS)

    The results of experiments on obtaining a tubular beam of hydrogen negative ions from a surface plasma source with emission ring slit of 100 mm diameter are described in the study. Conditions of burning of a high current ring discharge generating effectively hydrogen negative ions with current density up to 2.1 A/cm2 are investigated. The possibility of generation of intensive tubular beams of hydrogen negative ions by surface plasma sources is shown, the 2.4 A ion beam is obtained. The results of preliminary experiments on accelerating tubular beam up to 135 keV are described. Azymuthally uniform current density distribution of intensive tubular beams generated by discharges with a close electron drift in a surface plasma source with emission ring slit, absence of high-frequency oscillations in optimal conditions of sources operation as well as the possibility of the most complete use of generated by the discharge negative ions flow show the prospects of development of these sources for fast atom injectors

  9. Solid state generator for powerful radio frequency ion sources in neutral beam injection systems

    Energy Technology Data Exchange (ETDEWEB)

    Kraus, W.; Fantz, U.; Heinemann, B.; Franzen, P.

    2015-02-15

    Radio frequency ion sources used in neutral beam injection systems (NBI) of fusion machines are currently supplied by self-excited RF generators. These generators have both a low power efficiency and a limited frequency stability, therefore transistorized amplifiers are being considered for the power supply of the next generation of RF sources. A 75 kW generator, originally designed for broadcasting, has been tested with a negative ion source. High operational reliability and a very good matching to the plasma load has been demonstrated. These results make this generator type a very promising candidate for future NBI systems.

  10. CNGS - CERN Neutrinos to GRAN SASSO

    CERN Document Server

    Elsener, K

    2000-01-01

    The CNGS project was approved by CERN Council in December 1999. This report gives a short description of the Muon Neutrino beam to be built at CERN in the direction of the INFN Gran Sasso underground laboratory (LNGS). The first goal of this new facility is the production of sufficient Muon Neutrino in an energy region optimised for the detection of an adequate number of Tau neutrino - produced by oscillation - at LNGS. The layout, cost, schedule and the expected beam performance of the CNGS facility is summarised.

  11. In the CERN Library

    CERN Multimedia

    1963-01-01

    Seen in this picture is Noria Christophoridou, librarian of the Greek Atomic Energy Commission, who has been sent by her government to CERN for a year to widen her experience of library and documentation services. In the photograph she is providing information to Kurt Gottfried, a CERN visiting scientist from Harvard University, who is spending a year with CERN's Theory Division

  12. 2005 CERN Relay Race

    CERN Document Server

    Patrice Loiez

    2005-01-01

    The CERN Relay Race takes place each year in May and sees participants from all areas of the CERN staff. The winners in 2005 were The Shabbys with Los Latinos Volantes in second and Charmilles Technologies a close third. To add a touch of colour and levity, the CERN Jazz Club provided music at the finishing line.

  13. CERN Photowalk 2015

    CERN Multimedia

    2015-01-01

    CERN is organising a Photowalk on Friday 25 September 2015. At this event a few selected photographers will get the chance to come to CERN, the European Organization for Nuclear Research, for an exclusive behind-the-scenes tour of the laboratory. For more information: http://photowalk2015.web.cern.ch/

  14. Efficient phase-matching for difference frequency generation with pump of Bessel laser beams.

    Science.gov (United States)

    Liu, Pengxiang; Shi, Wei; Xu, Degang; Zhang, Xinzheng; Zhang, Guizhong; Yao, Jianquan

    2016-01-25

    A type of phase matching for difference frequency generation with Bessel-type pump beams is proposed. In this geometry, the phase matching is achieved in a cone around the laser path by properly controlling the beam profile. An experimental case that 1.5THz generation with ~2μm lasers pumped bulk GaAs crystal is considered. Calculations of the energy conversion characteristics are performed based on a semi-analytical model. The results indicate that this configuration could relax the phase matching condition in a wide range of nonlinear crystals and pump wavelengths. PMID:26832473

  15. Diffraction-resistant scalar beams generated by a parabolic reflector and a source of spherical waves.

    Science.gov (United States)

    Zamboni-Rached, Michel; de Assis, Mariana Carolina; Ambrosio, Leonardo A

    2015-07-01

    In this work, we propose the generation of diffraction-resistant beams by using a parabolic reflector and a source of spherical waves positioned at a point slightly displaced from its focus (away from the reflector). In our analysis, considering the reflector dimensions much greater than the wavelength, we describe the main characteristics of the resulting beams, showing their properties of resistance to the diffraction effects. Due to its simplicity, this method may be an interesting alternative for the generation of long-range diffraction-resistant waves.

  16. Diffraction Resistant Scalar Beams Generated by a Parabolic Reflector and a Source of Spherical Waves

    CERN Document Server

    Zamboni-Rached, Michel; Ambrosio, Leonardo A

    2015-01-01

    In this work, we propose the generation of diffraction resistant beams by using a parabolic reflector and a source of spherical waves positioned at a point slightly displaced from its focus (away from the reflector). In our analysis, considering the reflector dimensions much greater than the wavelength, we describe the main characteristics of the resulting beams, showing their properties of resistance to the diffraction effects. Due to its simplicity, this method may be an interesting alternative for the generation of long range diffraction resistant waves.

  17. Generation of a cold, intense relativistic electron beam using a magnetized foilless diode

    International Nuclear Information System (INIS)

    An annular electron beam with less than 30 mrad of angular velocity spread, a radius of 1 cm, and a current density exceeding 0.4 MA/cm2 has been generated with a magnetized foilless diode. The diode current loss is limited to less than a few percent by careful design of the tapered transition region connecting a self-magnetically insulated vacuum transmission line to the externally magnetized foilless diode. Details of the transition section design and operating characteristics of the electron beam generator are given

  18. 15 January 2010 - Vice-Chancellor & Chief Executive C. Snowden, University of Surrey, United Kingdom and Mrs Snowden visiting ALICE exhibition and experimental undeground area with Collabortion Spokesperson J. Schukraft and Beams Department Head P. Collier; Signature of the guest book with CERN Director-General R. Heuer.

    CERN Multimedia

    Maximilien Brice

    2010-01-01

    15 January 2010 - Vice-Chancellor & Chief Executive C. Snowden, University of Surrey, United Kingdom and Mrs Snowden visiting ALICE exhibition and experimental undeground area with Collabortion Spokesperson J. Schukraft and Beams Department Head P. Collier; Signature of the guest book with CERN Director-General R. Heuer.

  19. 14 November 2013 - Director of Indian Institute of Technology Indore P. Mathur with members of the Indian community working at CERN; visiting the LHC tunnel at Point 2, the ALICE experimental area and SM18 with ALICE Collaboration Spokesperson, Istituto Nazionale Fisica Nucleare P. Giubellino and Technology Department, Accelerator Beam Transfer Group Leader V. Mertens

    CERN Multimedia

    Jean-Claude Gadmer

    2013-01-01

    14 November 2013 - Director of Indian Institute of Technology Indore P. Mathur with members of the Indian community working at CERN; visiting the LHC tunnel at Point 2, the ALICE experimental area and SM18 with ALICE Collaboration Spokesperson, Istituto Nazionale Fisica Nucleare P. Giubellino and Technology Department, Accelerator Beam Transfer Group Leader V. Mertens

  20. 18 January 2011 - The British Royal Academy of Engineering in the LHC tunnel with CMS Collaboration Spokesperson G. Tonelli and Beams Department Head P. Collier; in the CERN Control Centre with P. Collier and LHC superconducting magnet test hall with Technology Department Head F. Bordry.

    CERN Multimedia

    Jean-Claude Gadmer

    2011-01-01

    18 January 2011 - The British Royal Academy of Engineering in the LHC tunnel with CMS Collaboration Spokesperson G. Tonelli and Beams Department Head P. Collier; in the CERN Control Centre with P. Collier and LHC superconducting magnet test hall with Technology Department Head F. Bordry.

  1. 23rd June 2010 - University of Bristol Head of the Aerospace Engineering Department and Professor of Aerospace Dynamics N. Lieven visiting CERN control centre with Beams Department Head P. Collier, visiting the LHC superconducting magnet test hall with R. Veness and CMS control centre with Collaboration Spokesperson G. Tonelli and CMS User J. Goldstein.

    CERN Multimedia

    Jean-Claude Gadmer

    2010-01-01

    23rd June 2010 - University of Bristol Head of the Aerospace Engineering Department and Professor of Aerospace Dynamics N. Lieven visiting CERN control centre with Beams Department Head P. Collier, visiting the LHC superconducting magnet test hall with R. Veness and CMS control centre with Collaboration Spokesperson G. Tonelli and CMS User J. Goldstein.

  2. CERN News: Slow ejection efficiency at the PS; Vacuum tests on the ISR; Fire in the neutrino beam-line; Prototype r.f . cavity for the Booster; Crane-bridge in ISR experimental hall; Modifications to the r.f . system at the PS

    CERN Multimedia

    1969-01-01

    CERN News: Slow ejection efficiency at the PS; Vacuum tests on the ISR; Fire in the neutrino beam-line; Prototype r.f . cavity for the Booster; Crane-bridge in ISR experimental hall; Modifications to the r.f . system at the PS

  3. Helping CERN give back to society

    CERN Multimedia

    2014-01-01

    The CERN & Society mission: ‘To spread the CERN spirit of scientific curiosity for the inspiration and benefit of society.’   Digital library schools in Africa, Arts@CERN, a beam line for schools competition and perhaps soon a dedicated biomedical research facility: CERN infrastructure and expertise have a great influence on society, and we have the potential to do much more. For that, however, we need help, and that’s why we have launched the CERN & Society initiative, which this week sees the publication of a new website for those who want to understand more about how our research touches everyday life, as well as for those who wish to help CERN in this new endeavour. Fundamental research fulfils a very human need. The quest to understand the universe we live in is as old as humanity itself, and CERN is in the vanguard of that effort today. For our scientists and engineers, pushing technology to the limit is part of their day job, and in doing so they ...

  4. Collimated Blue and Infrared Beams Generated by Two-Photon Excitation in Rb Vapor

    CERN Document Server

    Sell, J F; DePaola, B D; Knize, R J

    2013-01-01

    Utilizing two-photon excitation in hot Rb vapor we demonstrate the generation of collimated optical fields at 420 nm and 1324 nm. Input laser beams at 780 nm and 776 nm enter a heated Rb vapor cell collinear and circularly polarized, driving Rb atoms to the $5D_{5/2}$ state. Under phase-matching conditions coherence among the $5S_{1/2}\\rightarrow 5P_{3/2}\\rightarrow 5D_{5/2} \\rightarrow 6P_{3/2}$ transitions produces a blue (420 nm) beam by four-wave mixing. We also observe a forward and backward propagating IR (1324 nm) beam, due to cascading decays through the $6S_{1/2}\\rightarrow 5P_{1/2}$ states. Power saturation of the generated beams is investigated by scaling the input powers to greater than 200 mW, resulting in a coherent blue beam of 9.1 mW power, almost an order of magnitude larger than previously achieved. We measure the dependences of both beams in relation to the Rb density, the frequency detuning between Rb ground state hyperfine levels, and the input laser intensities.

  5. Generation of ninety-six angularly multiplexed KrF beams at Aurora

    International Nuclear Information System (INIS)

    The Aurora KrF laser facility is designed to produce ninety-six laser beams at 248 nm with total energy of -- 10 kJ. The 5-ns duration beams are angularly multiplexed to allow sequential amplification in electron-beam-pumped amplifiers. These amplifiers operated over a half-microsecond period. Previous to this investigation, all individual components of the Aurora system have been operated independently. As a first step toward integration of the full system, the author operated the front end, beam slicer, small-aperture module (SAM), and angle encoder to generate ninety-six angularly multiplexed beams. These beams have been delivered to the first of the three large amplifiers, which will boost the pulse train energy from <1 J to 10 kJ. Measurements to date have concentrated on the total energy of the pulse train and pulse shapes of the individual beams at positions preceding and following SAM. Measured gain through SAM is -- 13 with 20 the target figure. Relative pulse heights are preserved through SAM with the exception of the first pulse of the 12

  6. Density and potential measurements in an intense ion beam-generated plasma

    International Nuclear Information System (INIS)

    Neutral beams are created by intense large area ion beams which are neutralized in a gas cell. The interaction of the beam with the gas cell creates a plasma. Such a plasma is studied here. The basic plasma parameters, electron temperature, density, and plasma potential, are measured as a function of beam current and neutral gas pressure. These measurements are compared to a model based on the solution of Poisson's equation. Because of the cylindrical geometry the equation cannot be solved analytically. Details of the numerical method are presented. Three refinements to existing models have been added. (1) The beam creates ions by charge exchange as well as by ionization. (2) In the ionization process most of the ions are born at rest but some of the ions are born through a molecular dissociation process which provides them with substantial energy. (3) Electrons are trapped in the potential well of the system. Their distribution will be truncated by the well and the usual Boltzmann relation for the density variation with potential will be altered slightly. Analytical expressions for these effects are obtained and included in the computer generated solution. The model and data are in good agreement only when locally determined beam current profiles are used in the solution. These profiles are broader than those determined from beam dump calorimetry

  7. EUCYS prizewinner visits CERN

    CERN Multimedia

    Jennifer Toes

    2016-01-01

    Young Turkish student Baris Volkan Gürses visited CERN from 4 to 8 July after winning the prize in the 2015 European Contest for Young Scientists (EUCYS).    Baris Volkan Gürses, EUCYS prizewinner, visiting the Microcosm. After winning both regional and national competitions in Turkey, 18-year-old student Baris Volkan Gürses competed against 169 young scientists and was awarded a visit to CERN by EIROforum for his physics project in EUCYS 2015. His project, entitled “Generation of artificial gravity by using electrostatic force for prevention of muscle atrophy and osteoporosis occurring in gravity-free environments”, focused on the design of a mechanism to help with the impact of spaceflight on the human body. “My objective was to eliminate the negative effects of a gravity-free environment on astronauts who stay in space for longer periods of time, like in the International Space Station,” explained Volkan. &...

  8. CERN@school

    CERN Multimedia

    CERN Bulletin

    2010-01-01

    CERN’s educational programmes have inspired large numbers of physics teachers all over Europe to adopt innovative approaches to teaching.  Becky Parker, a former participant in the High School Teachers (HST) programme, has set up the CERN@school project, in which students are using Medipix chips to study cosmic rays. They have recently designed and are building Lucid, a detector that will be launched into space in 2011.   The LUCID detector designed by the Langton school. Take a school with the declared aim of ‘providing learning experiences which are enjoyable, stimulating and challenging and which encourage critical and innovative thinking’. Add to that a motivated teacher who wants to put it into practice and you have the perfect seeds for growing a new generation of young researchers. Becky Parker came to CERN in 2007. She observed how cutting-edge research is done here and decided to export it to her school. However, she didn’t just go back t...

  9. Modeling of discharges generated by electron beams in dense gases: Fountain and thunderstorm regimes

    International Nuclear Information System (INIS)

    In this paper we present an analysis of the predicted dynamics of plasmas generated in air and other gases by injecting beams of high-energy electrons. Two distinct regimes are found, differing in the way that the excess negative charge brought in by the ionizing electron beam is removed. In the first regime, called a fountain, the charge is removed by the back current of plasma electrons toward the injection foil. In the second, called a thunderstorm, a substantial cloud of negative charge accumulates, and the increased electric field near the cloud causes a streamer to strike between the cloud and a positive or grounded electrode, or between two clouds created by two different beams. A quantitative analysis, including electron beam propagation, electrodynamics, charge particle kinetics, and a simplified heat balance, is performed in a one-dimensional approximation

  10. A reflex glow discharge as a plasma source for broad area electron beam generation

    International Nuclear Information System (INIS)

    The authors demonstrated an electron beam generation scheme in which two glow discharge electron guns are used in a reflex configuration to create a dense and cold plasma in a large volume. The thermal electrons from this plasma, created mainly by electron beam ionization, are subsequently accelerated in the gap between two grids by an externally applied electric field to produce a broad area electron beam. This electron beam current density and energy are independently controlled by the voltage applied to the glow discharge guns and by the electric field sustained between the grids respectively. They present a schematic representation of the electron gun used in the experimental demonstration of the concept reported here

  11. LHCb: Beam and Background Monitoring and the Upgrade of the Timing and Fast Control System of the LHCb experiment at CERN

    CERN Multimedia

    Alessio, F

    2009-01-01

    The LHCb experiment at CERN is preparing for first real data taking, foreseen by the end of the year 2009 with the start-up of the LHC. A large amount of work of commissioning, tests and improvements of the full detector has been done in order to optimize its performance. During my first year as a Doctoral Student at CERN, I have been working on the timing and readout control of the LHCb experiment in the frame of the LHCb Online group. The group is responsible for the full data acquisition of the LHCb experiment, from the Front-End Electronics (FEE) to the storage of the data for offline analysis, as well as the Timing and Fast Control (TFC) system. The latter controls and distributes centrally timing and trigger information, as well as synchronous and asynchronous commands to the readout system. It is also responsible for receiving and adjusting the bunch and orbit clocks of the LHC machine and distributing it to the electronics of the whole experiment. It is of vital importance to assure that the timing o...

  12. Collide@CERN Geneva

    CERN Document Server

    CERN. Geneva; Kieffer, Robert; Blas Temino, Diego; Bertolucci, Sergio; Mr. Decelière, Rudy; Mr. Hänni, Vincent

    2014-01-01

    CERN, the Republic and Canton of Geneva, and the City of Geneva are delighted to invite you to “Collide@CERN Geneva Music”. Come to the public lecture about collisions between music and particle physics by the third winners of Collide@CERN Geneva, Vincent Hänni & Rudy Decelière, and their scientific inspiration partners, Diego Blas and Robert Kieffer. The event marks the beginning of their residency at CERN, and will be held at the CERN Globe of Science and Innovation on 16 October 2014 at 19.00. Doors will open at 18.30.

  13. CERN Photo club

    CERN Multimedia

    CERN Photo club

    2016-01-01

    The CERN Photo Club organizes in collaboration with Canon Switzerland a photo contest open to all members of the CERN (Persons with a CERN access card). The only restriction is that the photos must have been taken with a CANON camera (DSLR, bridge or compact) between 1 and 31 October 2016. Send your three best pictures at  Photo.Contest@cern.ch with a short description explaining the images. Further information on the Photo club website: http://photoclub.web.cern.ch/content/photo-contest-october-2016

  14. Britain at CERN

    CERN Multimedia

    CERN Press Office. Geneva

    1996-01-01

    On 8 October, H.E. Mr David Beattie, British Ambassador to Switzerland, Mr John R. Nichols, H.M. Consul-General in Geneva and, Prof. Christopher Llewellyn Smith, CERN*'s Director General, formally opened the industrial exhibition of thirty-three British hi-tech companies at CERN, which takes place from 8 to 11 October, 1996. The exhibition offers British companies the opportunity to display their products in fields that are of immediate importance to the scientists, engineers and technicians working at CERN, and also to scientists from non-Member States who take part in research projects at CERN.

  15. CERN Cricket Club

    CERN Multimedia

    CERN Cricket Club

    2010-01-01

    CERN Cricket Club Match Reports The cricket season is well under way, despite the weather, and several matches have been played. The match reporters have, however, found it too difficult to limit their reports to ¼ of a page, hence the reports have not appeared in the bulletin. All reports can be found at http://cern.ch/Club-Cricket/reports/reports.html The list of forthcoming matches can be consulted at http://cern.ch/Club-Cricket/fixtures.html Further information about the CERN Cricket Club can be found at http://cern.ch/Club-Cricket/

  16. X-ray FEL based on harmonics generation and electron beam outcoupling

    Energy Technology Data Exchange (ETDEWEB)

    Litvinenko, V.N.; Burnham, B. [Duke Univ., Durham, NC (United States)

    1995-12-31

    Electron beam outcoupling was suggested by N. A. Vinokurov as a method of optics independent outcoupling for high power FELs. The bunching of the electron beam is provided in a master oscillator. The prebunched electron beam then radiates coherently into an additional wiggler called the radiator. The electron beam is turned by an achromatic bend into this wiggler and its radiation propagates with a small angle with respect to the OK-4 optical axis. Thus, the radiation will pass around the mirror of the master oscillator optical cavity and can then be utilized. This scheme is perfectly suited for harmonic generation if the radiator wiggler is tuned on one of the master oscillator wavelength harmonics. This system is reminiscent of a klystron operating on a harmonic of the reference frequency. In this paper we present the theory of this device, its spectral and spatial characteristics of radiation, the optimization of the master oscillator, the achromatic bend and bunching for harmonic generation, and influence of beam parameters (energy spread, emittance, etc.) on generated power. Examples of possible storage ring and linac driven systems are discussed.

  17. Two exercises about neutrino departure times at CERN

    OpenAIRE

    Berg, Bernd A.; Hoeflich, Peter

    2011-01-01

    Two simple exercises are solved, which educators can use to awake interest of their students in subtleties of the CERN Neutrino beam to Grand Sasso (CNGS) experiment. The first one is about the statistical error of the average departure time of neutrinos from CERN. The second one about a hypothetical bias in the departure times.

  18. CARE-HHH-APD Workshop on Finalizing the Roadmap for the Upgrade of the CERN and GSI Accelerator Complex

    CERN Document Server

    Zimmermann, Frank; BEAM'07; BEAM 2007; Finalizing the Roadmap for the Upgrade of the LHC and GSI Accelerator Complex

    2008-01-01

    This report contains the Proceedings of the CARE-HHH-APD Event BEAM’07, “Finalizing the Roadmap for the Upgrade of the CERN & GSI Accelerator Complex,” which was held at CERN in Geneva, Switzerland, from 1 to 5 October 2007. BEAM’07 was primarily devoted to beam dynamics limitations for the two, or three, alternative baseline scenarios of the LHC luminosity upgrade and to critical design choices for the upgrade of the LHC injector complex at CERN and for the FAIR complex at GSI. It comprised five parts: (1) a Mini-Workshop on LHC+ Beam Performance, (2) a CERN-GSI Meeting on Collective Effects, (3) the Francesco Ruggiero Memorial Symposium, (4) a Mini-Workshop on the LHC Injectors Upgrade, and (5) the BEAM’07 Summaries. Topics addressed in the first mini-workshop of BEAM’07 ranged from the luminosity performance reach of the upgraded LHC in different scenarios, over the generation and stability of the future LHC beams, the turnaround time, beam–beam effects, luminosity levelling methods, and ...

  19. CERN honours Georges Charpak

    CERN Multimedia

    2009-01-01

    CERN pays tribute to the work of Georges Charpak at a colloquium in honour of his 85th birthday. var flash_video_player=get_video_player_path(); insert_player_for_external('Video/Public/Movies/2009/CERN-MOVIE-2009-008/CERN-MOVIE-2009-008-0753-kbps-480x360-25-fps-audio-64-kbps-44-kHz-stereo', 'mms://mediastream.cern.ch/MediaArchive/Video/Public/Movies/2009/CERN-MOVIE-2009-008/CERN-MOVIE-2009-008-Multirate-200-to-753-kbps-480x360.wmv', 'false', 480, 360, 'https://mediastream.cern.ch/MediaArchive/Video/Public/Movies/2009/CERN-MOVIE-2009-008/CERN-MOVIE-2009-008-posterframe-480x360-at-10-percent.jpg', '1167500', true, 'Video/Public/Movies/2009/CERN-MOVIE-2009-008/CERN-MOVIE-2009-008-0600-kbps-maxH-360-25-fps-audio-128-kbps-48-kHz-stereo.mp4'); Watch the video conference of Georges Charpak.   On 9 March CERN’s Main Auditorium was the venue for a fascinating and moving celebration marking the 85th birthday of Georges Charpak, who was awarded the Nobel Prize for Physics in 1992 for his inven...

  20. CERN Holiday Gift Guide

    CERN Multimedia

    2013-01-01

    Do you have last-minute gifts to get? Stuck for ideas? The CERN Shop and the ATLAS and CMS secretariats have some wonderfully unique gifts and stocking-fillers for sale this year - perfect for the physics fanatics in your life. Let's take a look...   1. CERN Notebook, 10 CHF - 2. CERN Pop-up book, 30 CHF - 3. USB Stick 8GB, 25 CHF - 4. CERN Tumbler, 12 CHF 5. ATLAS 3D Viewer, 5 CHF - 6. ATLAS Puzzle, 15 CHF - 7. CMS Umbrella, 25 CHF   These gifts are all available at the CERN Shop, with the exception of the ATLAS 3D Viewer and the CMS umbrella, which are only available from the respective secretariats. Don’t forget! If you’re from CERN, you still have time to take advantage of a 10% off discount at the CERN shop. Offer ends 20 December.

  1. Human response to individually controlled micro environment generated with localized chilled beam

    DEFF Research Database (Denmark)

    Uth, Simon C.; Nygaard, Linette; Bolashikov, Zhecho Dimitrov;

    2014-01-01

    Indoor environment in a single-office room created by a localised chilled beam with individual control of the primary air flow was studied. Response of 24 human subjects when exposed to the environment generated by the chilled beam was collected via questionnaires under a 2-hour exposure including...... different work tasks at three locations in the room. Response of the subjects to the environment generated with a chilled ceiling combined with mixing air distribution was used for comparison. The air temperature in the room was kept at 26 or 28 °C. Results show no significant difference in the overall and...... local thermal sensation reported by the subjects with the two systems. Both systems were equally acceptable. At 26°C the individual control of the localised chilled beam lead to higher acceptability of the work environment. At 28°C the acceptability decreased with the two systems. It was not acceptable...

  2. Tungsten disulphide based all fiber Q-switching cylindrical-vector beam generation

    Energy Technology Data Exchange (ETDEWEB)

    Lin, J.; Yan, K.; Zhou, Y. [Department of Optics and Optical Engineering, University of Science and Technology of China, Hefei 230026 (China); Xu, L. X., E-mail: xulixin@ustc.edu.cn; Gu, C. [Department of Optics and Optical Engineering, University of Science and Technology of China, Hefei 230026 (China); Haixi Collaborative Innovation Center for New Display Devices and Systems Integration, Fuzhou University, Fuzhou 350002 (China); Zhan, Q. W. [Electro-Optics Program, University of Dayton, Dayton, Ohio 45469 (United States)

    2015-11-09

    We proposed and demonstrated an all fiber passively Q-switching laser to generate cylindrical-vector beam, a two dimensional material, tungsten disulphide (WS{sub 2}), was adopted as a saturable absorber inside the laser cavity, while a few-mode fiber Bragg grating was used as a transverse mode-selective output coupler. The repetition rate of the Q-switching output pulses can be varied from 80 kHz to 120 kHz with a shortest duration of 958 ns. Attributed to the high damage threshold and polarization insensitivity of the WS{sub 2} based saturable absorber, the radially polarized beam and azimuthally polarized beam can be easily generated in the Q-switching fiber laser.

  3. The effects of nonlinear phase for the generation and propagation of finite energy Airy beams

    International Nuclear Information System (INIS)

    The generation of a high-power finite-energy Airy beam (FEAB) needs a high-power source laser which leads a nonlinear phase into the generation and propagation of the FEAB. We theoretically and numerically investigate how the nonlinear phase affects the generation and propagation of FEAB. The nonlinear phase is associated with the B-integral of the laser system. The second-order term of the nonlinear phase’s Taylor series can theoretically represent the impacts of nonlinear phase with small B-integral. The nonlinear phase significantly changes the peak intensity and the beam shape during the generation and propagation of FEAB. The variation becomes larger with increasing B-integral, and the bigger the truncation coefficient of FEAB, the smaller the B-integral domain. (paper)

  4. Generation of a high-brightness pulsed positron beam for the Munich scanning positron microscope

    Energy Technology Data Exchange (ETDEWEB)

    Piochacz, Christian

    2009-11-20

    Within the present work the prerequisites for the operation of the Munich scanning positron microscope (SPM) at the high intense neutron induced positron source Munich (NEPOMUC) were established. This was accomplished in two steps: Firstly, a re-moderation device was installed at the positron beam facility NEPOMUC, which enhances the brightness of the positron beam for all connected experiments. The second step was the design, set up and initial operation of the SPM interface for the high efficient conversion of the continuous beam into a bunched beam. The in-pile positron source NEPOMUC creates a positron beam with a diameter of typically 7 mm, a kinetic energy of 1 keV and an energy spread of 50 eV. The NEPOMUC re-moderator generates from this beam a low energy positron beam (20 - 200 eV) with a diameter of less than 2 mm and an energy spread well below 2.5 eV. This was achieved with an excellent total efficiency of 6.55{+-}0.25 %. The re-moderator was not only the rst step to implement the SPM at NEPOMUc, it enables also the operation of the pulsed low energy positron beam system (PLEPS). Within the present work, at this spectrometer rst positron lifetime measurements were performed, which revealed the defect types of an ion irradiated uranium molybdenum alloy. Moreover, the instruments which were already connected to the positron beam facility bene ts considerably of the high brightness enhancement. In the new SPM interface an additional re-moderation stage enhances the brightness of the beam even more and will enable positron lifetime measurements at the SPM with a lateral resolution below 1 {mu}m. The efficiency of the re-moderation process in this second stage was 24.5{+-}4.5 %. In order to convert high efficiently the continuous positron beam into a pulsed beam with a repetition rate of 50 MHz and a pulse duration of less than 50 ps, a sub-harmonic pre-bucher was combined with two sine wave bunchers. Furthermore, the additional re-moderation stage of the

  5. Generation of a high-brightness pulsed positron beam for the Munich scanning positron microscope

    International Nuclear Information System (INIS)

    Within the present work the prerequisites for the operation of the Munich scanning positron microscope (SPM) at the high intense neutron induced positron source Munich (NEPOMUC) were established. This was accomplished in two steps: Firstly, a re-moderation device was installed at the positron beam facility NEPOMUC, which enhances the brightness of the positron beam for all connected experiments. The second step was the design, set up and initial operation of the SPM interface for the high efficient conversion of the continuous beam into a bunched beam. The in-pile positron source NEPOMUC creates a positron beam with a diameter of typically 7 mm, a kinetic energy of 1 keV and an energy spread of 50 eV. The NEPOMUC re-moderator generates from this beam a low energy positron beam (20 - 200 eV) with a diameter of less than 2 mm and an energy spread well below 2.5 eV. This was achieved with an excellent total efficiency of 6.55±0.25 %. The re-moderator was not only the rst step to implement the SPM at NEPOMUc, it enables also the operation of the pulsed low energy positron beam system (PLEPS). Within the present work, at this spectrometer rst positron lifetime measurements were performed, which revealed the defect types of an ion irradiated uranium molybdenum alloy. Moreover, the instruments which were already connected to the positron beam facility bene ts considerably of the high brightness enhancement. In the new SPM interface an additional re-moderation stage enhances the brightness of the beam even more and will enable positron lifetime measurements at the SPM with a lateral resolution below 1 μm. The efficiency of the re-moderation process in this second stage was 24.5±4.5 %. In order to convert high efficiently the continuous positron beam into a pulsed beam with a repetition rate of 50 MHz and a pulse duration of less than 50 ps, a sub-harmonic pre-bucher was combined with two sine wave bunchers. Furthermore, the additional re-moderation stage of the SPM

  6. Generation of a pulsed low-energy electron beam using the channel spark device

    Science.gov (United States)

    Elgarhy, M. A. I.; Hassaballa, S. E.; Rashed, U. M.; ElSabbagh, M. M.; Soliman, H. M.; Saudy, A. H.

    2015-12-01

    For the generation of low-energy electron beam, the design and characteristics of channel spark discharge (CSD) operating at a low voltage are presented in this paper. The discharge voltage, discharge current, X-ray emissions, and electron beam current were experimentally determined. The effects of the applied voltage, working gas pressure, and external capacitance on the CSD and beam parameters were measured. At an applied voltage of 11 kV, an oxygen gas pressure of 25 mTorr, and an external capacitance of 16.45 nF, the maximum measured current was 900 A. The discharge current increased with the increase in the pressure and capacitance, while its periodic time decreased with the increase in the pressure. Two types of the discharge were identified and recorded: the hollow cathode discharge and the conduction discharge. A Faraday cup was used to measure the beam current. The maximum measured beam current was 120 A, and the beam signal exhibited two peaks. The increase in both the external capacitance and the applied discharge voltage increased the maximum electron beam current. The electron-beam pulse time decreased with the increase in the gas pressure at a constant voltage and increased with the decrease in the applied discharge voltage. At an applied voltage of 11 kV and an oxygen gas pressure of 15 mTorr, the maximum beam energy was 2.8 keV. The X-ray signal intensity decreased with the increase in the gas pressure and increased with the increase in the capacitance.

  7. Generation of a pulsed low-energy electron beam using the channel spark device

    International Nuclear Information System (INIS)

    For the generation of low-energy electron beam, the design and characteristics of channel spark discharge (CSD) operating at a low voltage are presented in this paper. The discharge voltage, discharge current, X-ray emissions, and electron beam current were experimentally determined. The effects of the applied voltage, working gas pressure, and external capacitance on the CSD and beam parameters were measured. At an applied voltage of 11 kV, an oxygen gas pressure of 25 mTorr, and an external capacitance of 16.45 nF, the maximum measured current was 900 A. The discharge current increased with the increase in the pressure and capacitance, while its periodic time decreased with the increase in the pressure. Two types of the discharge were identified and recorded: the hollow cathode discharge and the conduction discharge. A Faraday cup was used to measure the beam current. The maximum measured beam current was 120 A, and the beam signal exhibited two peaks. The increase in both the external capacitance and the applied discharge voltage increased the maximum electron beam current. The electron-beam pulse time decreased with the increase in the gas pressure at a constant voltage and increased with the decrease in the applied discharge voltage. At an applied voltage of 11 kV and an oxygen gas pressure of 15 mTorr, the maximum beam energy was 2.8 keV. The X-ray signal intensity decreased with the increase in the gas pressure and increased with the increase in the capacitance

  8. Generation of a pulsed low-energy electron beam using the channel spark device

    Energy Technology Data Exchange (ETDEWEB)

    Elgarhy, M. A. I., E-mail: elgarhy@azhar.edu.eg; Hassaballa, S. E.; Rashed, U. M.; ElSabbagh, M. M.; Saudy, A. H. [Physics Department, Faculty of Science, Al-Azhar University, Cairo (Egypt); Soliman, H. M. [Plasma and Nuclear Fusion Department, Atomic Energy Authority, Enshas (Egypt)

    2015-12-15

    For the generation of low-energy electron beam, the design and characteristics of channel spark discharge (CSD) operating at a low voltage are presented in this paper. The discharge voltage, discharge current, X-ray emissions, and electron beam current were experimentally determined. The effects of the applied voltage, working gas pressure, and external capacitance on the CSD and beam parameters were measured. At an applied voltage of 11 kV, an oxygen gas pressure of 25 mTorr, and an external capacitance of 16.45 nF, the maximum measured current was 900 A. The discharge current increased with the increase in the pressure and capacitance, while its periodic time decreased with the increase in the pressure. Two types of the discharge were identified and recorded: the hollow cathode discharge and the conduction discharge. A Faraday cup was used to measure the beam current. The maximum measured beam current was 120 A, and the beam signal exhibited two peaks. The increase in both the external capacitance and the applied discharge voltage increased the maximum electron beam current. The electron-beam pulse time decreased with the increase in the gas pressure at a constant voltage and increased with the decrease in the applied discharge voltage. At an applied voltage of 11 kV and an oxygen gas pressure of 15 mTorr, the maximum beam energy was 2.8 keV. The X-ray signal intensity decreased with the increase in the gas pressure and increased with the increase in the capacitance.

  9. Characterization of a channel spark discharge and the generated electron beam

    International Nuclear Information System (INIS)

    We report on an experimental study of a channel spark discharge (CSD) and the generated electron beam. The CSD was operated at a discharge voltage Ud≤30 kV and a discharge current Id≤3.5 kA. The CSD system consists of a glass tube placed between a hollow cathode and a grounded anode electrode. The parameters of the CSD operation, the potential distribution along the glass tube, and the generated beam were studied by electrical, optical, and spectroscopic diagnostics in the Ar gas pressure range of P=0.005-2 Pa. At P≥0.5 Pa, electrons with energy ∼eUd appeared prior to the start of the main CSD with a current amplitude ≤10-4Id. These high-energy electrons are responsible for the initiation of the CSD inside the glass tube. The generation of the electron beam which was composed of low-energy electrons with a current amplitude up to 3 kA occurred during a fast fall in the discharge voltage. Decreasing the Ar gas pressure below 0.1 Pa allows one to increase significantly the beam duration and the part of the high-energy electrons in the beam, and to increase the efficiency of the electron beam generation up to 75%. The high-current CSD inside the glass tube is accompanied by the formation of a plasma consisting of protons, Ar II, Ar III, C II-IV, and O II-IV ions. The plasma electron density and temperature were found to be in the ranges of 1015-1016 cm-3 and 10-15 eV, respectively

  10. Microwave Generation Power in a Nonrelativistic Electron Beam with Virtual Cathode in a Retarding Electric Field

    CERN Document Server

    Egorov, E N; Koronovskii, A A; Hramov, A E; Morozov, M Y; Kalinin, Yu.A.

    2006-01-01

    The power of microwave generation in a nonrelativistic electron beam with virtual cathode formed in a static retarding electric field (low-voltage vircator system) has been studied experimentally and by means of numerical simulation within the framework of a one-dimensional theory. The limits of applicability of the one-dimensional theory have been experimentally determined.

  11. Microwave generation power in a nonrelativistic electron beam with virtual cathode in a retarding electric field

    Science.gov (United States)

    Egorov, E. N.; Kalinin, Yu. A.; Koronovskiĭ, A. A.; Hramov, A. E.; Morozov, M. Yu.

    2006-05-01

    The power of microwave generation in a nonrelativistic electron beam with virtual cathode formed in a static retarding electric field (low-voltage vircator system) has been studied experimentally and by means of numerical simulation within the framework of a one-dimensional theory. The limits of applicability of the one-dimensional theory have been experimentally determined.

  12. Alpha particle diagnostic beam line system to generate an intense Li0 beam with an ORNL SITEX source

    International Nuclear Information System (INIS)

    The Oak Ridge National Laboratory (ORNL) SITEX (Surface Ionization with Transverse Extraction) negative ion source utilizes a 100-V/20-A reflex arc discharge in a 1300-gauss magnetic field to generate Cs+ ions and H+ or D+ ions, depending on the beam required. A shaped molybdenum plate is placed directly behind the arc column. Cesium coverage on this plate is used to minimize the surface work function, which requires two-thirds of a monolayer coverage. Cesium coverage ia adjusted both by cesium flow control into the arc discharge chamber and by temperature control of the converter using gaseous-helium cooling channels in the converter plate. Normal converter operational temperatures are 3000 to 5000C H-/D- beams are generated at the biased converter surface (-150 V with respect to the anode) by Cs+ sputtering of absorbed hydrogen or deuterium and by the reflection-conversion mechanism of H+/D+ ions which strike the converter surface at 150 eV. The negative ions are accelerated through the 150-V plasma sheath at the converter surface and are focused by the converter geometry and magnetic field so as to pass through the exit aperture with minimum angular divergence. The ion optics of the SITEX accelerator has been calculated using the ORNL 3-D optics code and results in a divergence perpendicular to the slot of theta/sub perpendicular rms/ = 0.350 and parallel to the slot of theta/sub parallel rms/ = 0.180. This beam divergence should be adequate for injection into a radio frequency quadrupole (RFQ) for further acceleration

  13. A day in the CERN Control Centre

    CERN Multimedia

    Rosaria Marraffino

    2015-01-01

    The CERN Control Centre (CCC) is the nerve centre of the CERN beam systems. From this room, the experts prepare, monitor, adjust, and control the particle beams that circulate throughout the accelerator complex while ensuring that the services and the technical infrastructure work flawlessly. Buttons, screens, telephones, lights (but no sound): in the CCC, everything is ready to make it possible for the LHC to reach the unprecedented energies expected at Run 2.   Seen from above, the CERN Control Centre resembles the shape of a quadrupole magnet. The consoles are distributed in four circles, called “islands”, dedicated to the LHC, the SPS, the PS Complex and the Technical Infrastructure (TI) respectively. Spread between TI and LHC are the Cryogenics consoles. Being in the same room allows the 24h-manned islands to be constantly in touch with one another, thus ensuring the best performance of the machines. At the LHC island, operators are currently busy training the magnet...

  14. Can two partially coherent cosh-Gaussian beams generate far fields with the same spectral degree of coherence?

    Institute of Scientific and Technical Information of China (English)

    Lü Su-Ye; Lü Bai-Da

    2009-01-01

    Taking partially coherent cosh-Gaussian (ChG) beams as an example of more general partially coherent beams,we have studied the spectral degree of coherence of partially coherent ChG beams in the far field. It is shown that,unlike Gaussian Schell-model (GSM) beams,in the strict sense there do not exist two partially coherent ChG beams which can generate far fields with the same spectral degree of coherence. However,under certain conditions it is possible to find two partially coherent ChG beams with the same spectral degree of coherence in the far field.

  15. Rotman Lens-Based Circular Array for Generating Five-mode OAM Radio Beams

    Science.gov (United States)

    Bai, Xu-Dong; Liang, Xian-Ling; Li, Jian-Ping; Wang, Kun; Geng, Jun-Ping; Jin, Rong-Hong

    2016-06-01

    Recently, vortex beam carrying orbital angular momentum (OAM) for radio communications has attracted much attention for its potential of transmitting multiple signals simultaneously at the same frequency, which can be used to increase the channel capacity. However, most of the methods for getting multi-mode OAM radio beams remain up to now mainly at simulation level, since their implementations are of complicated structure and very high cost. This paper provides an effective design of generating five-mode OAM radio beams by using the Rotman lens-fed antenna array. The Rotman lens is a viable beamforming approach instead of electronically scanned arrays for its low cost and the ease of implementation. The lens-fed array employs a two-layer structure for size reduction, and the lens body and the antenna array are segregated by a common ground plane to eliminate spurious radiation and thus improve the performance of the OAM beams. The measured results coincide with the simulated ones, which verified the effectiveness of the proposed design for generating multi-mode OAM beams.

  16. Generation and focusing of electron beams with initial transverse-longitudinal correlation

    Energy Technology Data Exchange (ETDEWEB)

    Harris, J. R., E-mail: john.harris@colostate.edu [Department of Electrical and Computer Engineering, Colorado State University, Fort Collins, Colorado 80523 (United States); Lewellen, J. W. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Poole, B. R. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States)

    2014-10-07

    In charged particle beams, one of the roles played by space charge is to couple the transverse and longitudinal dynamics of the beam. This can lead to very complex phenomena which are generally studied using computer simulations. However, in some cases models based on phenomenological or analytic approximations can provide valuable insight into the system behavior. In this paper, we employ such approximations to investigate the conditions under which all the slices of a space charge dominated electron beam with slowly varying current could be focused to a waist with the same radius and at the same location, independent of slice current, and show that this can be accomplished approximately if the initial transverse-longitudinal correlation introduced onto the beam by the electron gun is chosen to compensate for the transverse-longitudinal correlation introduced onto the beam in the drift section. The validity of our approximations is assessed by use of progressively more realistic calculations. We also consider several design elements of electron guns that affect the initial correlations in the beams they generate.

  17. MeV Argon ion beam generation with narrow energy spread

    CERN Document Server

    Xu, Jiancai; Shen, Baifei; Zhang, Hui; Li, Shun; Yu, Yong; Li, Jinfeng; Lu, Xiaoming; Wang, Cheng; Wang, Xinliang; Liang, Xiaoyan; Leng, Yuxin; Li, Ruxin; Xu, Zhizhan

    2016-01-01

    Laser driven particle acceleration has shown remarkable progresses in generating multi-GeV electron bunches and 10s of MeV ion beams based on high-power laser facilities. Intense laser pulse offers the acceleration field of 1012 Volt per meter, several orders of magnitude larger than that in conventional accelerators, enabling compact devices. Here we report that a highly-collimated argon ion beam with narrow energy spread is produced by irradiating a 45-fs fully-relativistic laser pulse onto an argon cluster target. The highly-charged (Argon ion with charge state of 16+) heavy ion beam has a minimum absolute energy spread of 0.19 MeV per nucleon at the energy peak of 0.39 MeV per nucleon. we identify a novel scheme from particle-in-cell simulations that greatly reduces the beam energy spread. The laser-driven intense plasma wakefield has a strong modulation on the ion beam in a way that the low energy part is cut off. The pre-accelerated argon ion beam from Coulomb explosion thus becomes more mono-energetic ...

  18. La neutrino factory del CERN e i problemi radiologici dell'annesso proton driver

    CERN Document Server

    Bressan, Beatrice Alessandra

    2001-01-01

    The thesis, La Neutrino Factory del CERN e i problemi radiologici dell’annesso proton driver (CERN Neutrino Factory and the radiological problems of the annex proton driver), deals with the new particle accelerators for the post LHC (Large Hadron Collider) era. The first part of the work describes these innovative accelerators with particular emphasis on the muon collider which, producing μ+/μ− collisions in the 100 GeV energy range, should explore deeply the Higgs Boson physics. The second part of the thesis describes the three-step scenario proposed for the muon accelerators: Neutrino Factory, Higgs Factory and a collider with TeV C.M. energy. The third chapter explains how a Neutrino Factory works. In a Neutrino Factory the neutrino beam is generated by high-energy muons decaying in a storage ring. The muons are produced by pions generated in a target bombarded by an intense proton beam. In the CERN project, the proton beam is produced by a super conducting LINAC (with 75 Hz frequency and 2.2 GeV ene...

  19. CERN Table Tennis Club

    CERN Multimedia

    CERN Table Tennis Club

    2014-01-01

    CERN Table Tennis Club Announcing CERN 60th Anniversary Table Tennis Tournament to take place at CERN, from July 1 to July 15, 2014   The CERN Table Tennis Club, reborn in 2008, is encouraging people at CERN to take more regular exercise. This is why the Club, thanks to the strong support of the CERN Staff Association, installed last season a first outdoor table on the terrace of restaurant # 1, and will install another one this season on the terrace of Restaurant # 2. Table tennis provides both physical exercise and friendly social interactions. The CERN Table Tennis club is happy to use the unique opportunity of the 60th CERN anniversary to promote table tennis at CERN, as it is a game that everybody can easily play, regardless of level. Table tennis is particularly well suited for CERN, as many great physicists play table tennis, as you might already know: “Heisenberg could not even bear to lose a game of table tennis”; “Otto Frisch played a lot of table tennis;...

  20. Electron beam manipulation, injection and acceleration in plasma wakefield accelerators by optically generated plasma density spikes

    Science.gov (United States)

    Wittig, Georg; Karger, Oliver S.; Knetsch, Alexander; Xi, Yunfeng; Deng, Aihua; Rosenzweig, James B.; Bruhwiler, David L.; Smith, Jonathan; Sheng, Zheng-Ming; Jaroszynski, Dino A.; Manahan, Grace G.; Hidding, Bernhard

    2016-09-01

    We discuss considerations regarding a novel and robust scheme for optically triggered electron bunch generation in plasma wakefield accelerators [1]. In this technique, a transversely propagating focused laser pulse ignites a quasi-stationary plasma column before the arrival of the plasma wake. This localized plasma density enhancement or optical "plasma torch" distorts the blowout during the arrival of the electron drive bunch and modifies the electron trajectories, resulting in controlled injection. By changing the gas density, and the laser pulse parameters such as beam waist and intensity, and by moving the focal point of the laser pulse, the shape of the plasma torch, and therefore the generated trailing beam, can be tuned easily. The proposed method is much more flexible and faster in generating gas density transitions when compared to hydrodynamics-based methods, and it accommodates experimentalists needs as it is a purely optical process and straightforward to implement.

  1. A simplified approach for the generation of projection data for cone beam geometry

    Indian Academy of Sciences (India)

    Tushar Roy; P S Sarkar; Amar Sinha

    2011-04-01

    To test a developed reconstruction algorithm for cone beam geometry, whether it is transmission or emission tomography, one needs projection data. Generally, mathematical phantoms are generated in three dimensions and the projection for all rotation angles is calculated. For non-symmetric objects, the process is cumbersome and computation intensive. This paper describes a simple methodology for the generation of projection data for cone beam geometry for both transmission and emission tomographies by knowing the object’s attenuation and/or source spatial distribution details as input. The object details such as internal geometrical distribution are nowhere involved in the projection data calculation. This simple approach uses the pixilated object matrix values in terms of the matrix indices and spatial geometrical coordinates. The projection data of some typical phantoms (generated using this approach) are reconstructed using standard FDK algorithm and Novikov’s inversion formula. Correlation between the original and reconstructed images has been calculated to compare the image quality.

  2. The Low-Level Control System for the CERN PS Multi-Turn Extraction Kickers

    CERN Document Server

    Schipper, J; Boucly, C; Carlier, E; Fowler, T; Gaudillet, H; Noulibos, R; Sermeus, L

    2010-01-01

    To reduce the beam losses when preparing high intensity proton beam for the CERN Neutrino to Gran Sasso (CNGS) facility, a new Multi-Turn extraction (MTE) scheme has been implemented in the PS, to replace the present Continuous Transfer (CT) to the SPS. Industrial off-the-shelf components have been used for the low-level part of the MTE kicker control system. National Instruments PXI systems are used to control the high voltage pulse generators and a SIEMENS programmable logic controller (PLC) handles the centralised oil cooling and gas insulation sub-systems

  3. The propagation and growth of whistler mode waves generated by electron beams in earth's bow shock

    Science.gov (United States)

    Tokar, R. L.; Gurnett, D. A.

    1985-01-01

    In this study, the propagation and growth of whistler mode waves generated by electron beams within earth's bow shock is investigated using a planar model for the bow shock and a model electron distribution function. Within the shock, the model electron distribution function possesses a field-aligned T greater than T beam that is directed toward the magnetosheath. Waves with frequencies between about 1 and 100 Hz with a wide range of wave normal angles are generated by the beam via Landau and anomalous cyclotron resonances. However, because the growth rate is small and because the wave packets traverse the shock quickly, these waves do not attain large amplitudes. Waves with frequencies between about 30 and 150 Hz with a wide range of wave normal angles are generated by the beam via the normal cyclotron resonance. The ray paths for most of these waves are directed toward the solar wind although some wave packets, due to plasma convection travel transverse to the shock normal. These wave packets grow to large amplitudes because they spend a long time in the growth region. The results suggest that whistler mode noise within the shock should increase in amplitude with increasing upstream theta sub Bn. The study provides an explanation for the origin of much of the whistler mode turbulence observed at the bow shock.

  4. Orbital Angular Momentum in Noncollinear Second Harmonic Generation by off-axis vortex beams

    CERN Document Server

    Bovino, Fabio Antonio; Giardina, Maurizio; Sibilia, Concita

    2011-01-01

    We experimentally study the behavior of orbital angular momentum (OAM) of light in a noncollinear second harmonic generation (SHG) process. The experiment is performed by using a type I BBO crystal under phase matching conditions with femtosecond pumping fields at 830 nm. Two specular off-axis vortex beams carrying fractional orbital angular momentum at the fundamental frequency (FF) are used. We analyze the behavior of the OAM of the SH signal when the optical vortex of each input field at the FF is displaced from the beam's axis. We obtain different spatial configurations of the SH field, always carrying the same zero angular momentum.

  5. The CERN-Gran Sasso Neutrino Program

    OpenAIRE

    Duchesneau, D.

    2002-01-01

    This paper reviews the current experimental program envisaged with the future CERN neutrino beam called CNGS. Two detectors, OPERA and ICARUS, are under preparation and should investigate the neutrino properties coming from the CNGS to shed light on neutrino oscillation physics.

  6. Proton-driven plasma acceleration at CERN

    International Nuclear Information System (INIS)

    Plasma-based acceleration methods have seen important progress over the last years. Recently, it has been proposed to experimentally study plasma acceleration driven by proton beams, in addition to the established research directions of electron and laser-driven plasmas. This talk presents the planned experiment and the research efforts carried out at CERN.

  7. CERN students display their work

    CERN Multimedia

    Anaïs Schaeffer

    2011-01-01

    The first poster session by students working on the LHC experiments, organised by the LPCC, was a great success. Showcasing the talents of over a hundred young physicists from all over the world, it was an opportunity for everyone at CERN to check out the wide range of research work being done by the new generation of physicists at CERN.   At 5.30 p.m. on Wednesday 23 March, the first poster session by CERN students took place in Restaurant No.1, where no fewer than 87 posters went on public display. The students were split into 8 groups according to their research field* and all were on hand to answer the questions of an inquisitive audience. TH Department's Michelangelo Mangano, who is head of the LHC Physics Centre at CERN (LPCC) and is responsible for the initiative, confirms that nothing was left to chance, even the choice of date: "We wanted to make the most of the general enthusiasm around the winter conferences and the meeting of the LHC Experiments Committee to present the stud...

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

    OpenAIRE

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

    2012-01-01

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

  9. Study of second harmonic generation by high power laser beam in magneto plasma

    International Nuclear Information System (INIS)

    This paper examines the problem of nonlinear generation of second harmonic of a high power laser pulse propagating in magnetized plasma. The propagation of strong laser beam is proposed in the direction perpendicular to a relatively weak static magnetic field. The laser pulse is taken to be linearly polarized, with the orientation of its electric field that corresponds to an ordinary electromagnetic wave. Besides the standard ponderomotive nonlinearity, the appropriate wave equation also contains the nonlinearity that arises from the relativistic electron jitter velocities. During its propagation, the laser beam gets filamented on account of relativistic and pondermotive nonlinearities present in the plasma. The generated plasma wave gets coupled into the filamentary structures of the pump beam. Due to the expected presence of the beam filamentation, the work has been carried out by considering modified paraxial approximation (i.e., beyond the standard paraxial approximation of a very broad beam). It is found that the power of the plasma wave is significantly affected by the magnetic field strength in the presence of both relativistic and pondermotive nonlinearities. It is investigated that the second harmonic generation is also considerably modified by altering the strength of magnetic field. To see the effect of static magnetic field on the harmonic generation, a key parameter, i.e., the ratio of the cyclotron frequency ωc=eB0/mc over the laser frequency ω0 has been used, where c is the velocity of light, m and e are the mass and charge of the electron and B0 is the externally applied magnetic field.

  10. Young Artists@ CERN

    CERN Document Server

    2004-01-01

    In view of 50th anniversary of CERN, about 20 young artists will be visiting CERN from 26 to 31 January to learn about the laboratory's research and the mysterious world of particle physics. The impressions they take home will be the main inspiration for the artwork they will then produce for an exhibition to be inaugurated in October 2004 as part of CERN's 50th anniversary celebration. We are looking for scientists who are interested in the Art-Science synergy and who can volunteer to discuss their work at CERN to these young artists during this week (25-31/01). Please contact renilde.vanden.broeck@cern.ch if you are interested. The project is called Young Artists@ CERN and for more information look at this website: http://www.hep.ucl.ac.uk/~andy/CERNart/

  11. CERN and the environment

    CERN Multimedia

    Corinne Pralavorio

    2016-01-01

    New webpages answer common questions about CERN and the environment.   One of the new public webpages dedicated to CERN and the environment. Do your neighbours ever ask you about CERN’s environmental impact? And about radiation in particular? If so, the answers to those questions can now be found online on a new set of public webpages dedicated to CERN and the environment. These pages, put together by the Occupational Health, Safety and Environmental Protection (HSE) unit and the groups responsible for CERN's site maintenance, contain a wealth of information on topics linked to the environment, such as biodiversity at CERN, waste management, ionising radiation, and water and electricity consumption. “CERN forms part of the local landscape, with its numerous sites and scientific activities. It’s understandable that people living nearby have questions about the impact of these activities and it’s important that we respond with complete transp...

  12. German visits to CERN

    CERN Multimedia

    2007-01-01

    State secretary to Germany's Federal Ministry of Education and Research, Frieder Meyer-Krahmer, with CERN's Director-General Robert Aymar.On 21 February, Professor Frieder Meyer-Krahmer, State Secretary to Germany's Federal Ministry of Education and Research, came to CERN. He visited the ALICE and ATLAS experiments and the computing centre before meeting the CERN's Director-General, some German physicists and members of the top management. The Minister of Science, Research and the Arts of the Baden-Württemberg regional government, Peter Frankenberg, and CERN's Director-General, Robert Aymar, signing an agreement on education. In the background: Sigurd Lettow, CERN's Director of Finance and Human Resources, and Karl-Heinz Meisel, Rector of the Fachhochschule Karlsruhe. The Minister of Science, Research and the Arts of the Baden-Württemberg regional government, Prof. Peter Frankenberg, visited CERN on 23 February. He was accompanied by the Rector of the Fachhochschule Karlsruhe, Prof. Karl-Heinz Meisel, and b...

  13. Germany at CERN

    CERN Multimedia

    2005-01-01

    From left to right: Maximilian Metzger, CERN's Secretary-General, Hermann Schunck, Director at the German Federal Ministry of Education and Research, and Robert Aymar, CERN's Director-General, talking to Wolfgang Holler from Butting, one of the companies at the "Germany at CERN" exhibition. Far right : Susanne-Corinna Langer-Greipl from BMBF, delegate to the CERN Finance Committee. For three days, CERN's Main Building was transformed into a showcase for German industry. Twenty-nine companies from sectors related to particle physics (electrical engineering, vacuum and low temperature technology, radiation protection, etc.) were here for the ninth "Germany at CERN" exhibition, organised by the German Federal Ministry of Education and Research (BMBF), which gave them the opportunity to meet scientists and administrators from the Laboratory. On 1 March the exhibition was visited by a German delegation headed by Dr Hermann Schunck, Director at BMBF.

  14. CERN Cricket club

    CERN Multimedia

    CERN Cricket club

    2015-01-01

    The CERN Cricket Club 2015 season begins soon, the first net practice is scheduled (weather permitting) for Thursday April 16th, at 18:00! The club is always looking for new players and newcomers will be made very welcome. Anyone who is interested in joining the club should sign up on our web site: http://cern.ch/Club-Cricket/ or turn up for net practice, which takes place each Thursday evening from April 16th (apart from CERN official holidays) until the end of September (starting at 18:00 to around 19:30) at the CERN Prévessin site: http://club-cricket.web.cern.ch/Club-Cricket/CERN-Ground.html The first match will be at home on Sunday, April 19th against Rhone CC from Lyon.

  15. Beamline for schools beam line training day

    CERN Multimedia

    Photo Service, CERN

    2014-01-01

    The first two teams to participate in CERN's Beamline for Schools project spent their second day at CERN learning the basics of beam physics, and visiting their experimental setup at the T9 beam line in CERN's East Hall on the Meyrin site.

  16. CERN - better than science fiction!

    CERN Multimedia

    2007-01-01

    From left to right: Allan Cameron (Production Designer), Sam Breckham (Location Manager), James Gillies (Head of Communication at CERN), Jacques Fichet (from the CERN audiovisual service), Rolf Landua (former spokesman of the ATHENA antihydrogen experiment at CERN and Head of CERN's Education Group), Ron Howard, and Renilde Vanden Broeck (CERN press officer).

  17. The CERN PC farm

    CERN Multimedia

    Serge Bellegarde

    2005-01-01

    Housed in the CERN Computer Centre, these banks of computers process and store data produced on the CERN systems. When the LHC starts operation in 2008, it will produce enough data every year to fill a stack of CDs 20 km tall. To handle this huge amount of data, CERN has also developed the Grid, allowing the processing power to be shared between computer centres around the world.

  18. Sharing resources@CERN

    CERN Multimedia

    Maximilien Brice

    2002-01-01

    The library is launching a 'sharing resources@CERN' campaign, aiming to increase the library's utility by including the thousands of books bought by individual groups at CERN. This will improve sharing of information among CERN staff and users. Photo 01: L. to r. Eduardo Aldaz, from the PS division, Corrado Pettenati, Head Librarian, and Isabel Bejar, from the ST division, read their divisional copies of the same book.

  19. CERN Relay Race

    CERN Document Server

    CERN Running Club

    2010-01-01

    The CERN relay race will take place around the Meyrin site on Thursday 20 May, starting at 12.15. If possible, please avoid driving on the site during this 20-minute period. If you do meet runners while driving your car, please STOP until they have all passed. Thank you for your cooperation. Details on the route, and how to register your team for the relay race, can be found at: https://espace.cern.ch/Running-Club/CERN-Relay

  20. Radiation protection at CERN

    OpenAIRE

    Forkel-Wirth, Doris; Roesler, Stefan; Silari, Marco; Streit-Bianchi, Marilena; Theis, Christian; Vincke, Heinz; Vincke, Helmut

    2013-01-01

    This paper gives a brief overview of the general principles of radiation protection legislation; explains radiological quantities and units, including some basic facts about radioactivity and the biological effects of radiation; and gives an overview of the classification of radiological areas at CERN, radiation fields at high-energy accelerators, and the radiation monitoring system used at CERN. A short section addresses the ALARA approach used at CERN.

  1. Parabolic antennas, and circular slot arrays, for the generation of Non-Diffracting Beams of Microwaves

    CERN Document Server

    Zamboni-Rached, Michel

    2014-01-01

    We propose in detail Antennas for generating Non-Diffracting Beams of Microwaves, for instance with frequencies of the order of 10 GHz, obtaining fair results even when having recourse to realistic apertures endowed with reasonable diameters. Our first proposal refers mainly to sets of suitable annular slits, having in mind various possible applications, including remote sensing. Our second proposal --which constitutes one of the main aims of this paper-- refers to the alternative, rather simple, use of a Parabolic Reflector, illuminated by a spherical wave source located on the paraboloid axis but slightly displaced with respect to the Focus of the Paraboloid. Such a parabolic reflector yields "extended focus" (non-diffracting) beams. [OCIS codes: 999.9999; 070.7545; 050.1120; 280.0280; 050.1755; 070.0070; 200.0200. Keywords: Non-Diffracting Waves; Microwaves; Remote sensing; Annular Arrays; Bessel beams; Extended focus; Reflecting paraboloids; Parabolic reflectors; Parabolic antennas].

  2. Generation of intense ion beams and their application to controlled fusion research

    International Nuclear Information System (INIS)

    Successful generation of pulsed multi-kA proton beams in the energy range 0.2 to 1.7 MeV using existing pulsed power technology has been achieved by three different techniques: reflex triodes, pinched electron-beam diodes and magnetically insulated diodes. Peak current densities in excess of 10 kAcm-2 have been observed on the NRL Gamble II machine and over 1.0 kAcm-2 on the Cornell Neptune machine. Peak total ion currents above 200 kA are produced by Gamble II. The potential applications of intense ion beams to magnetic confinement include (i) plasma heating and (ii) ion rings. A summary of continuous theoretical and experimental investigations on these applications is presented. (author)

  3. Generation of anomalously energetic suprathermal electrons by an electron beam interacting with a nonuniform plasma

    CERN Document Server

    Sydorenko, D; Chen, L; Ventzek, P L G

    2015-01-01

    Generation of anomalously energetic suprathermal electrons was observed in simulation of a high- voltage dc discharge with electron emission from the cathode. An electron beam produced by the emission interacts with the nonuniform plasma in the discharge via a two-stream instability. Efficient energy transfer from the beam to the plasma electrons is ensured by the plasma nonuniformity. The electron beam excites plasma waves whose wavelength and phase speed gradually decrease towards anode. The short waves near the anode accelerate plasma bulk electrons to suprathermal energies. The sheath near the anode reflects some of the accelerated electrons back into the plasma. These electrons travel through the plasma, reflect near the cathode, and enter the accelerating area again but with a higher energy than before. Such particles are accelerated to energies much higher than after the first acceleration. This mechanism plays a role in explaining earlier experimental observations of energetic suprathermal electrons i...

  4. CERN software developers gathering in September

    CERN Multimedia

    Antonella Del Rosso

    2015-01-01

    Hundreds of developers work on many different projects at CERN – from data analysis to beam operations and administrative applications. As of this September, they will have an opportunity to meet each other at the newly established Developers@CERN Forum.   “We go to conferences elsewhere but we hardly ever meet here at CERN, where we all work on our own separate software projects,” says José Carlos Luna, a member of the IT department and one of the organisers of the first Developers@CERN Forum. Indeed, although several CERN departments have software developers working in their teams, there is no proper “community” built around them. The first Developers@CERN Forum will be held on 28 and 29 September. The event is being organised by a few developers from the IT department, together with colleagues from the GS and EN departments. Its main scope is to reach out to all the departments in an effort to bring all CERN’s software dev...

  5. Generation and modelling of megavoltage photon beams for contrast-enhanced radiation therapy

    Science.gov (United States)

    Robar, J. L.

    2006-11-01

    Contrast-enhanced radiation therapy (CERT) is a treatment approach involving the irradiation of tumours containing high atomic number (Z) contrast media, using low-quality x-ray beams. This work describes the experimental generation of x-ray beams using a linear accelerator with low-Z target materials (beryllium and aluminium), in order to produce photon energy spectra appropriate for CERT. Measurements were made to compare the experimental beams to conventional linear accelerator photon beams in terms of per cent depth dose. Monte Carlo simulation was used to model the generation of each beam, and models were validated against experimental measurement. Validated models were used to demonstrate changes in photon spectra as well as to quantify the variation of tumour dose enhancement with iodinated contrast medium concentration in a simulated tumour volume. Finally, the ratio of the linear attenuation coefficient for iodinated contrast medium relative to water was determined experimentally as a function of iodine concentration. Beams created with low-Z targets show significant changes in energy spectra compared to conventional beams. For the 4 MeV/Be beam, for example, 33% of photons have energies below 60 keV. Measurements and calculation show that both the linear attenuation coefficient ratio and dose enhancement factor (DEF) increase most rapidly at concentrations below 46 mg I ml-1. There is a significant dependence of DEF on electron energy and a lesser dependence on target material. The 4 MeV/Be beam is the most promising in terms of magnitude of DEF—for example, DEF values of 1.16 and 1.29 are obtained for concentrations of 20 mg I ml-1 and 50 mg I ml-1, respectively. DEF will increase or decrease, respectively, for shallower or deeper tumours at a rate of approximately 1.1% cm-1. In summary, we show that significant dose enhancement is possible by altering the linear accelerator target and filtration, but the magnitude is highly dependent on contrast

  6. Britain at CERN

    CERN Multimedia

    2000-01-01

    H. E. Mr Christopher Hulse, Ambassador of United Kingdom in Switzerland, CERN Director General Luciano Maiani, Sir David Wright, Chief Executive of British Trade International and Roger Cashmore, CERN Director of research visit the Britain at CERN exhibition. From 14 to 17 November 30 British companies exhibited leading edge technologies at CERN. This is Britain's 18th exhibition at CERN since 1968. Out of the 30 companies, which attended the Britain at CERN exhibition in 1998, 25 have received an order or a contract relating to CERN during the last two years. The exhibition was inaugurated on Tuesday by Sir David Wright, Chief Executive of British Trade International. He was accompanied by H.E. Mr Christopher Hulse CMG, OBE, Her Majesty's Ambassador to Switzerland, and Mr. David Roberts, Deputy Head of Mission and Director of Trade Promotion at the British Embassy in Bern. CERN Director-General, Professor Luciano Maiani, underlined the major contribution of British physicists to CERN, pointing out the fact ...

  7. Integrity at CERN

    CERN Document Server

    Department, HR

    2015-01-01

    In the fulfillment of its mission, CERN relies upon the trust and material support of its Member States and partners, and is committed to exercising exemplary stewardship of the resources with which it is entrusted. Accordingly, CERN expects the highest level of integrity from all its contributors (whether members of the personnel, consultants, contractors working on site, or persons engaged in any other capacity at or on behalf of CERN). Integrity is a core value of CERN, defined in the Code of Conduct as “behaving ethically, with intellectual honesty and being accountable for one’s own actions”.

  8. Dual branch high voltage pulse generator for the beam extraction of the Large Hadron Collider

    CERN Document Server

    Bonthond, J; Ducimetière, L; Jansson, U; Vossenberg, Eugène B

    2002-01-01

    The LHC beam extraction kicker system, MKD, is composed of 15 fast kicker magnets per beam to extract the particles in one turn from the collider and to dispose them, after dilution, on an external absorber. Each magnet is powered by a separate pulse generator. The original single branch generator consisted of a discharge capacitor in series with a solid state closing switch left bracket 1 right bracket operating at 30 kV. In combination with a parallel freewheel diode stack this generator produced a current pulse of 2.7 mus rise time, 18.5 kA amplitude and about 1.8 ms fall time, of which only about 90 mus are needed to dump the beam. The freewheel diode circuit is equipped with a flat top current droop compensation network, consisting of a low voltage, low stray inductance, high current discharge capacitor. Extensive reliability studies have meanwhile suggested to further increase the operational safety of this crucial system by equipping each generator with two parallel branches. This paper presents the re...

  9. Generation of a focused proton beam with a self-magnetically BΘ-insulated ion diode

    International Nuclear Information System (INIS)

    A self-magnetically BΘ -insulated ion diode was investigated and optimized at the pulsed power line KALIF (2 MV, 50 ns, 2 Ω) to produce a focused and pulsed high-intensity proton beam for generation of high-power density in matter. This diode is characterized by an azimuthal insulating magnetic field that is generated by the diode current. The beam is neutralized by electrons from the cathode vanes, so that neither a gas filled drift space nor foils are needed. The beam therefore propagates in vacuum and repeated shots are possible without changing parts. The protons had energies up to 1.8 MeV and the proton content in the ion beam was about 50%. The maximum total diode current was about 800 kA and its efficiency was as high as 70%. The beam microdivergence was determined to be 1.1 degree. The radial dependence of the proton current density was measured and is proportional to r-1.74. This result was confirmed by 2D quasistatic particle-in-cell simulations. The focus was optimized by adjusting the anode shape and the gap geometry and by decreasing the beam divergence. The FWHM diameter of the focus at a distance of 300 mm was about 10 mm and the resulting focused power density was 0.13 TW/cm2. The effect of the gap distance on focusing and impedance was investigated and it was found necessary to adjust the gap to better than 0.1 mm over the total 30-cm-diam anode to obtain the best performance. The electron loss and the corresponding erosion at the posts that hold the anode was reduced. The lifetime is now limited by the plastic anode insert to 10--15 pulses. Based on these results a ''small BΘ diode'' is suggested for which a power density increase of a factor of 3 is estimated

  10. Study of fast electron generation using multi beam of LFEX-class laser

    Science.gov (United States)

    Hata, M.; Sakagami, H.; Johzaki, T.; Sentoku, Y.; Nagatomo, H.

    2016-05-01

    Fast Ignition Realization Experiment project phase-I (FIREX-I) is being performed at Institute of Laser Engineering, Osaka University. In this project, the four-beam bundled high-energy Petawatt laser (LFEX) is being operated. LFEX laser provides great multi-beam irradiation flexibility, with the possibility of arrange the pulses in temporal sequence, spatially separate them in distinct spots of focus them in a single spot. In this paper, we study the two- beam interference effects on high-intensity picosecond laser-plasma interaction (LPI) by twodimensional relativistic Particle-In-Cell simulations. The interference causes surface perturbation, which enhances laser absorption and underdense plasma generation, increasing the accelerated electron number and their slope temperature. The laser-to-electron energy conversion efficiency for two-beam interference case is suitable for Fast Ignition (FI) compared to the single beam case, but the increment of fast electron divergence leads to lower energy coupling. To optimize the target design for FI, these interference effects should be taken into consideration.

  11. Polarization-controllable Airy beams generated via a photoaligned director-variant liquid crystal mask

    Science.gov (United States)

    Wei, Bing-Yan; Chen, Peng; Hu, Wei; Ji, Wei; Zheng, Li-Yang; Ge, Shi-Jun; Ming, Yang; Chigrinov, Vladimir; Lu, Yan-Qing

    2015-12-01

    Researches on Airy beams have grown explosively since the first demonstration in 2007 due to the distinguishing properties of nondiffraction, transverse acceleration and self-healing. To date, a simple and compact approach for generating Airy beams in high quality and efficiency has remained challenging. Here, we propose and demonstrate a liquid crystal (LC) polarization Airy mask (PAM) featured by spatially variant LC azimuthal director. The PAM is fabricated through photoaligning LC via a polarization-sensitive alignment agent suophonic azo dye SD1. Thanks to the special design, a novel feature of polarization-controllable switch between dual Airy beams of orthogonal circular polarization is presented. The molecular-level continuity of LC director significantly improves the quality and efficiency of resultant Airy beams. Besides, the PAM can handle intense light due to the absence of absorptive electrodes. Additional merits of compact size, low cost and broad wavelength tolerance are also exhibited. This work settles a fundamental requirement for Airy beam applications of optical manipulations, biology science and even some uncharted territories.

  12. The generation and acceleration of low emittance flat beams for future linear colliders

    Energy Technology Data Exchange (ETDEWEB)

    Raubenheimer, T.O.

    1991-11-01

    Many future linear collider designs call for electron and positron beams with normalized rms horizontal and vertical emittances of {gamma}{epsilon}{sub x} = 3{times}10{sup {minus}6} m-rad and {gamma}{epsilon}{sub y} = 3{times}10{sup {minus}8} m-rad; these are a factor of 10 to 100 below those observed in the Stanford Linear Collider. In this dissertation, we examine the feasibility of achieving beams with these very small vertical emittances. We examine the limitations encountered during both the generation and the subsequent acceleration of such low emittance beams. We consider collective limitations, such as wakefields, space charge effects, scattering processes, and ion trapping; and also how intensity limitations, such as anomalous dispersion, betatron coupling, and pulse-to-pulse beam jitter. In general, the minimum emittance in both the generation and the acceleration stages is limited by the transverse misalignments of the accelerator components. We describe a few techniques of correcting the effect of these errors, thereby easing the alignment tolerances by over an order of magnitude. Finally, we also calculate ``fundamental`` limitations on the minimum vertical emittance; these do not constrain the current designs but may prove important in the future.

  13. The generation and acceleration of low emittance flat beams for future linear colliders

    Energy Technology Data Exchange (ETDEWEB)

    Raubenheimer, T.O.

    1991-11-01

    Many future linear collider designs call for electron and positron beams with normalized rms horizontal and vertical emittances of {gamma}{epsilon}{sub x} = 3{times}10{sup {minus}6} m-rad and {gamma}{epsilon}{sub y} = 3{times}10{sup {minus}8} m-rad; these are a factor of 10 to 100 below those observed in the Stanford Linear Collider. In this dissertation, we examine the feasibility of achieving beams with these very small vertical emittances. We examine the limitations encountered during both the generation and the subsequent acceleration of such low emittance beams. We consider collective limitations, such as wakefields, space charge effects, scattering processes, and ion trapping; and also how intensity limitations, such as anomalous dispersion, betatron coupling, and pulse-to-pulse beam jitter. In general, the minimum emittance in both the generation and the acceleration stages is limited by the transverse misalignments of the accelerator components. We describe a few techniques of correcting the effect of these errors, thereby easing the alignment tolerances by over an order of magnitude. Finally, we also calculate fundamental'' limitations on the minimum vertical emittance; these do not constrain the current designs but may prove important in the future.

  14. Scattered hard X-ray and γ-ray generation from a chromatic electron beam

    Energy Technology Data Exchange (ETDEWEB)

    Coleman, J. E. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Welch, D. R.; Miller, C. L. [Voss Scientific, Albuquerque, New Mexico 87108 (United States)

    2015-11-14

    An array of photon diagnostics has been deployed on a high power relativistic electron beam diode. Electrons are extracted through a 17.8 cm diode from the surface discharge of a carbon fiber velvet cathode with a nominal diode voltage of 3.8 MV. <10% of the 100 ns electron pulse is composed of off energy electrons (1–3 MeV) accelerated during the rise and fall of the pulse that impact the stainless steel beam pipe and generate a Bremsstrahlung spectrum of 0.1–3 MeV photons with a total count of 10{sup 11}. The principal objective of these experiments is to quantify the electron beam dynamics and spatial dynamics of the hard X-ray and γ-ray flux generated in the diode region. A qualitative comparison of experimental and calculated results are presented, including time and energy resolved electron beam propagation and scattered photon measurements with X-ray PIN diodes and a photomultiplier tube indicating a dose dependence on the diode voltage >V{sup 4} and detected photon counts of nearly 10{sup 6} at a radial distance of 1 m which corresponds to dose ∼40 μrad at 1 m.

  15. Generation and application of the soft X-ray laser beam based on capillary discharge

    International Nuclear Information System (INIS)

    In this work we report on the generation and characterization of a focused soft X-ray laser beam with intensity and energy density that exceed the threshold for the ablation of PMMA. We demonstrate a feasibility of direct ablation of holes using a focused soft X-ray laser beam. Ablated craters in PMMA/gold-covered-PMMA samples were obtained by focusing the soft X-ray Ar8+ laser pulses generated by a 46.9 nm tabletop capillary-discharge-pumped driver with a spherical Si/Sc multilayer mirror. It was found that the focused beam is capable by one shot to ablate PMMA, even if the focus is significantly influenced by astigmatism. Analysis of the laser beam footprints by atomic force microscope shows that ablated holes have periodic surface structure (similarly as Laser-Induced Periodic Surface Structure) with period ∼2,8 μm and with peak-to-peak depth ∼5-10 nm.

  16. Scattered hard X-ray and γ-ray generation from a chromatic electron beam

    International Nuclear Information System (INIS)

    An array of photon diagnostics has been deployed on a high power relativistic electron beam diode. Electrons are extracted through a 17.8 cm diode from the surface discharge of a carbon fiber velvet cathode with a nominal diode voltage of 3.8 MV. <10% of the 100 ns electron pulse is composed of off energy electrons (1–3 MeV) accelerated during the rise and fall of the pulse that impact the stainless steel beam pipe and generate a Bremsstrahlung spectrum of 0.1–3 MeV photons with a total count of 1011. The principal objective of these experiments is to quantify the electron beam dynamics and spatial dynamics of the hard X-ray and γ-ray flux generated in the diode region. A qualitative comparison of experimental and calculated results are presented, including time and energy resolved electron beam propagation and scattered photon measurements with X-ray PIN diodes and a photomultiplier tube indicating a dose dependence on the diode voltage >V4 and detected photon counts of nearly 106 at a radial distance of 1 m which corresponds to dose ∼40 μrad at 1 m

  17. The generation and acceleration of low emittance flat beams for future linear colliders

    International Nuclear Information System (INIS)

    Many future linear collider designs call for electron and positron beams with normalized rms horizontal and vertical emittances of γεx = 3x10-6 m-rad and γεy = 3x10-8 m-rad; these are a factor of 10 to 100 below those observed in the Stanford Linear Collider. In this dissertation, we examine the feasibility of achieving beams with these very small vertical emittances. We examine the limitations encountered during both the generation and the subsequent acceleration of such low emittance beams. We consider collective limitations, such as wakefields, space charge effects, scattering processes, and ion trapping; and also how intensity limitations, such as anomalous dispersion, betatron coupling, and pulse-to-pulse beam jitter. In general, the minimum emittance in both the generation and the acceleration stages is limited by the transverse misalignments of the accelerator components. We describe a few techniques of correcting the effect of these errors, thereby easing the alignment tolerances by over an order of magnitude. Finally, we also calculate ''fundamental'' limitations on the minimum vertical emittance; these do not constrain the current designs but may prove important in the future

  18. Testing Thermo-acoustic Sound Generation in Water with Proton and Laser Beams

    CERN Document Server

    Graf, K; Hoessl, J; Kappes, A; Karg, T; Katz, U; Lahmann, R; Naumann, C; Salomon, K; Stegmann, C

    2005-01-01

    Experiments were performed at a proton accelerator and an infrared laser acility to investigate the sound generation caused by the energy deposition of pulsed particle and laser beams in water. The beams with an energy range of 1 PeV to 400 PeV per proton beam spill and up to 10 EeV for the laser pulse were dumped into a water volume and the resulting acoustic signals were recorded with pressure sensitive sensors. Measurements were performed at varying pulse energies, sensor positions, beam diameters and temperatures. The data is well described by simulations based on the thermo-acoustic model. This implies that the primary mechanism for sound generation by the energy deposition of particles propagating in water is the local heating of the media giving rise to an expansion or contraction of the medium resulting in a pressure pulse with bipolar shape. A possible application of this effect would be the acoustical detection of neutrinos with energies greater than 1 EeV.

  19. Radiation damage in the diamond based beam condition monitors of the CMS experiment at the Large Hadron Collider (LHC) at CERN

    CERN Document Server

    Guthoff, Moritz; Dabrowski, Anne; De Boer, Wim; Stickland, David; Lange, Wolfgang; Lohmann, Wolfgang

    2013-01-01

    The Beam Condition Monitor (BCM) of the CMS detector at the LHC is a protection device similar to the LHC Beam Loss Monitor system. While the electronics used is the same, poly-crystalline Chemical Vapor Deposition (pCVD) diamonds are used instead of ionization chambers as the BCM sensor material. The main purpose of the system is the protection of the silicon Pixel and Strip tracking detectors by inducing a beam dump, if the beam losses are too high in the CMS detector. By comparing the detector current with the instantaneous luminosity, the BCM detector ef fi ciency can be monitored. The number of radiation-induced defects in the diamond, reduces the charge collection distance, and hence lowers the signal. The number of these induced defects can be simulated using the FLUKA Monte Carlo simulation. The cross-section for creating defects increases with decreasing energies of the impinging particles. This explains, why diamond sensors mounted close to heavy calorimeters experience more radiation damage, becaus...

  20. Experiments on high-power ion beam generation in self-insulated diodes

    International Nuclear Information System (INIS)

    Experimental results are given on high-power ion beams (HPIB) generation in a vacuum spherical focusing diode with self-magnetic insulation, obtained from the nanosecond accelerator PARUS with 0.2-TW power and 60-ns pulse duration for a matched load. When the passive plasma source of the ions was used, the efficiency of the HPIB generation was measured to be as high as 20% for 700-kV diode voltage and 10-kA/cm2 beam density in the focal plane. The application of a coaxial plasma opening switch (POS) prior to the diode resulted in a factor-of-1.8 increase in the diode power in comparison with a match operation in the absence of a POS. (author)