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Sample records for tevatron electron lens

  1. Pulser for the Tevatron electron lens gun

    Energy Technology Data Exchange (ETDEWEB)

    Iouri Terechkine et al.

    2004-05-18

    To compensate for beam-beam interaction in Tevatron, an ''electron lens'' is considered to be an effective instrument. When a bunch of electrons with energy in the range (10-16) kV is overlapping with a bunch of antiprotons, the resulting focusing force for antiprotons can be adjusted by changing the electron beam current and by profiling its radial distribution. There exist several scenarios of how the system must function. According to one of them, an electron gun that supplies electrons must be fed by voltage pulses that follow with the frequency of antiproton bunches circulating in the Tevatron, which is about 2.5 MHz. To provide focusing tailored for each individual antiproton bunch, a modulator of the gun (pulser) must allow pulse-to-pulse voltage change. This report will cover main approaches to a design of a pulser for use with the gun of the Tevatron Electron Lens.

  2. Magnetic system of the Tevatron electron lens

    International Nuclear Information System (INIS)

    Bogdanov, I.; Kozub, S.; Pleskach, V.; Sytnik, V.; Tkachenko, L.; Zintchenko, S.; Zubko, V.; Kuznetsov, G.; Sery, A.; Shiltsev, V.

    2000-01-01

    The Tevatron Electron Lens (TEL) system consisting of seven SC and four conventional magnets has been developed and fabricated in IHEP for increase of luminosity in Tevatron. The SC cable tension and preload of SC coils are calculated. The chosen cable design and cooling of the SC magnets ensure sufficient temperature margin for operating of SC magnets and their safety during quench. The system of conventional and SC solenoids create necessary trajectory of magnetic field lines for the TEL electron beam motion. SC dipoles and warm correctors permit to carry out correction of the electron beam motion [ru

  3. Electron Beam Generation in Tevatron Electron Lenses

    International Nuclear Information System (INIS)

    Kamerdzhiev, V.; Kuznetsov, G.; Shiltsev, V.; Solyak, N.; Tiunov, M.

    2006-01-01

    New type of high perveance electron guns with convex cathode has been developed. Three guns described in this article are built to provide transverse electron current density distributions needed for Electron Lenses for beam-beam compensation in the Tevatron collider. The current distribution can be controlled either by the gun geometry or by voltage on a special control electrode located near cathode. We present the designs of the guns and report results of beam measurements on the test bench. Because of their high current density and low transverse temperature of electrons, electron guns of this type can be used in electron cooling and beam-beam compensation devices

  4. Electron beam generation in Tevatron electron lenses

    International Nuclear Information System (INIS)

    Kamerdzhiev, V.; Kuznetsov, G.; Shiltsev, V.; Solyak, N.; Tiunov, M.

    2006-01-01

    New type of high perveance electron guns with convex cathode has been developed. Three guns described in this article are built to provide transverse electron current density distributions needed for Electron Lenses for beam-beam compensation in the Tevatron collider. The current distribution can be controlled either by the gun geometry or by voltage on a special control electrode located near cathode. We present the designs of the guns and report results of beam measurements on the test bench. Because of their high current density and low transverse temperature of electrons, electron guns of this type can be used in electron cooling and beam-beam compensation devices

  5. Tevatron Electron Lenses: Design and Operation

    Energy Technology Data Exchange (ETDEWEB)

    Shiltsev, Vladimir; /Fermilab; Bishofberger, Kip; /Los Alamos; Kamerdzhiev, Vsevolod; /Fermilab; Kozub, Sergei; /Serpukhov, IHEP; Kufer, Matthew; Kuznetsov, Gennady; Martinez, Alexander; Olson, Marvin; Pfeffer, Howard; Saewert, Greg; Scarpine, Vic; /Fermilab /SLAC /Fermilab /Serpukhov, IHEP /Novosibirsk, IYF /Serpukhov, IHEP /Fermilab

    2008-08-01

    The beam-beam effects have been the dominating sources of beam loss and lifetime limitations in the Tevatron proton-antiproton collider [1]. Electron lenses were originally proposed for compensation of electromagnetic long-range and head-on beam-beam interactions of proton and antiproton beams [2]. Results of successful employment of two electron lenses built and installed in the Tevatron are reported in [3,4,5]. In this paper we present design features of the Tevatron electron lenses (TELs), discuss the generation of electron beams, describe different modes of operation and outline the technical parameters of various subsystems.

  6. Guide for 3D WARP simulations of hollow electron beam lenses. Practical explanation on basis of Tevatron electron lens test stand

    Energy Technology Data Exchange (ETDEWEB)

    Moens, Vince [Ecole Polytechnique Federale de Lausanne (EPFL) (Switzerland)

    2014-06-08

    The purpose of this guide is to help successive students handle WARP. It outlines the installation of WARP on personal computers as well as super-computers and clusters. It furthermore teaches the reader how to handle the WARP environment and run basic scripts. Lastly it outlines how to execute the current Hollow Electron Beam Lens scripts.

  7. Tevatron Electron Lenses: Design and Operation

    Energy Technology Data Exchange (ETDEWEB)

    Shiltsev, Vladimir; /Fermilab; Bishofberger, Kip; /Los Alamos; Kamerdzhiev, Vsevolod; /Fermilab; Kozub, Sergei; /Serpukhov, IHEP; Kufer, Matthew; Kuznetsov, Gennady; Martinez, Alexander; Olson, Marvin; Pfeffer, Howard; Saewert, Greg; Scarpine, Vic; /Fermilab; Seryi, Andrei; /SLAC; Solyak, Nikolai; /Fermilab; Sytnik, Veniamin; /Serpukhov, IHEP; Tiunov, Mikhail; /Novosibirsk, IYF; Tkachenko, Leonid; /Serpukhov, IHEP; Wildman, David; Wolff, Daniel; Zhang, Xiao-Long; /Fermilab

    2011-09-12

    Fermilab's Tevatron is currently the world's highest energy accelerator in which tightly focused beams of 980 GeV protons and antiprotons collide at two dedicated interaction points (IPs). Both beams share the same beam pipe and magnet aperture and, in order to avoid multiple detrimental head-on collisions, the beams are placed on separated orbits everywhere except the main IPs by using high-voltage (HV) electrostatic separators. The electromagnetic beam-beam interaction at the main IPs together with the long-range interactions between separated beams adversely affect the collider performance, reducing the luminosity integral per store (period of continuous collisions) by 10-30%. Tuning the collider operation for optimal performance becomes more and more cumbersome as the beam intensities and luminosity increase. The long-range effects which (besides being nonlinear) vary from bunch to bunch are particularly hard to mitigate. A comprehensive review of the beam-beam effects in the Tevatron Collider Run II can be found in Ref. [1]. The beam-beam effects have been the dominating sources of beam loss and lifetime limitations in the Tevatron proton-antiproton collider [1]. Electron lenses were originally proposed for compensation of electromagnetic long-range and head-on beam-beam interactions of proton and antiproton beams [2]. Results of successful employment of two electron lenses built and installed in the Tevatron are reported in [3,4,5]. In this paper we present design features of the Tevatron electron lenses (TELs), discuss the generation of electron beams, describe different modes of operation and outline the technical parameters of various subsystems.

  8. Simulations of the electron cloud buildups and suppressions in Tevatron and main injector

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Xiaolong; Ostiguy, Jean-Francois; Chou, Weiren; /Fermilab

    2007-06-01

    To assess the effects of the electron cloud on Main Injector intensity upgrades, simulations of the cloud buildup were carried out using POSINST and compared with ECLOUD. Results indicate that even assuming an optimistic 1.3 maximum secondary electron yield, the electron cloud remains a serious concern for the planned future operational mode with 500 bunches, 3e11 proton per bunch. Electron cloud buildup can be mitigated in various ways. We consider a plausible scenario involving solenoids in straight section and a single clearing strip electrode (like SNEG in Tevatron) held at a potential of 500V. Simulations with parameters corresponding to Tevatron and Main Injector operating conditions at locations where special electron cloud detectors have been installed have been carried out and are in satisfactory agreement with preliminary measurements.

  9. Contact lens surface by electron beam

    International Nuclear Information System (INIS)

    Shin, Jung Hyuck; Lee, Suk Ju; Hwang, Kwang Ha; Jeon Jin

    2011-01-01

    Contact lens materials needs good biocompatibility, high refractive index, high optical transparency, high water content etc. Surface treat method by using plasma and radiation can modify the physical and/or chemical properties of the contact lens surface. Radiation technology such as electron beam irradiation can apply to polymerization reaction and enhance the functionality of the polymer.The purpose of this study is to modify of contact lens surface by using Eb irradiation technology. Electron beam was irradiated to the contact lens surface which was synthesized thermal polymerization method and commercial contact lens to modify physical and chemical properties. Ft-IR, XP, UV-vis spectrophotometer, water content, oxygen trans-metastability were used to characterize the surface state, physicochemical, and optical property of the contact lens treated with Eb. The water content and oxygen transmissibility of the contact lens treated with Eb were increased due to increase in the hydrophilic group such as O-C=O and OH group on the contact lens surface which could be produced by possible reaction between carbon and oxygen during the Eb irradiation. All of the lenses showed the high optical transmittance above 90%. In this case of B/Es, TES, Ti contact lens, the optical transmittance decreased about 5% with increasing Eb dose in the wavelength of UV-B region. The contact lens modified by Eb irradiation could improve the physical properties of the contact lens such as water content and oxygen transmissibility

  10. Electron Lens Construction for the Integrable Optics Test Accelerator at Fermilab

    Energy Technology Data Exchange (ETDEWEB)

    McGee, Mike [Fermilab; Carlson, Kermit [Fermilab; Nobrega, Lucy [Fermilab; Stancari, Giulio [Fermilab; Valishev, Alexander [Fermilab

    2016-06-01

    The Integrable Optics Test Accelerator (IOTA) is proposed for operation at Fermilab. The goal of IOTA is to create practical nonlinear accelerator focusing systems with a large frequency spread and stable particle motion. The IOTA is a 40 m circumference, 150 MeV (e-), 2.5 MeV (p⁺) diagnostic test ring. Construction of an electron lens for IOTA is necessary for both electron and proton operation. Components required for the Electron Lens design include; a 0.8 T conventional water-cooled main solenoid, and magnetic bending and focusing elements. The foundation of the design relies on repurposing the Fermilab Tevatron Electron Lens II (TELII) gun and collector under ultra-high vacuum (UHV) conditions.

  11. Beam Dynamics in an Electron Lens with the Warp Particle-in-cell Code

    CERN Document Server

    Stancari, Giulio; Redaelli, Stefano

    2014-01-01

    Electron lenses are a mature technique for beam manipulation in colliders and storage rings. In an electron lens, a pulsed, magnetically confined electron beam with a given current-density profile interacts with the circulating beam to obtain the desired effect. Electron lenses were used in the Fermilab Tevatron collider for beam-beam compensation, for abort-gap clearing, and for halo scraping. They will be used in RHIC at BNL for head-on beam-beam compensation, and their application to the Large Hadron Collider for halo control is under development. At Fermilab, electron lenses will be implemented as lattice elements for nonlinear integrable optics. The design of electron lenses requires tools to calculate the kicks and wakefields experienced by the circulating beam. We use the Warp particle-in-cell code to study generation, transport, and evolution of the electron beam. For the first time, a fully 3-dimensional code is used for this purpose.

  12. Electronic states in a quantum lens

    International Nuclear Information System (INIS)

    Rodriguez, Arezky H.; Trallero-Giner, C.; Ulloa, S. E.; Marin-Antuna, J.

    2001-01-01

    We present a model to find analytically the electronic states in self-assembled quantum dots with a truncated spherical cap (''lens'') geometry. A conformal analytical image is designed to map the quantum dot boundary into a dot with semispherical shape. The Hamiltonian for a carrier confined in the quantum lens is correspondingly mapped into an equivalent operator and its eigenvalues and eigenfunctions for the corresponding Dirichlet problem are analyzed. A modified Rayleigh-Schro''dinger perturbation theory is presented to obtain analytical expressions for the energy levels and wave functions as a function of the spherical cap height b and radius a of the circular cross section. Calculations for a hard wall confinement potential are presented, and the effect of decreasing symmetry on the energy values and eigenfunctions of the lens-shape quantum dot is studied. As the degeneracies of a semicircular geometry are broken for b≠a, our perturbation approach allows tracking of the split states. Energy states and electronic wave functions with m=0 present the most pronounced influence on the reduction of the lens height. The method and expressions presented here can be straightforwardly extended to deal with more general Hamiltonians, including strains and valence-band coupling effects in Group III--V and Group II--VI self-assembled quantum dots

  13. Sharing of secondary electrons by in-lens and out-lens detector in low-voltage scanning electron microscope equipped with immersion lens.

    Science.gov (United States)

    Kumagai, Kazuhiro; Sekiguchi, Takashi

    2009-03-01

    To understand secondary electron (SE) image formation with in-lens and out-lens detector in low-voltage scanning electron microscopy (LV-SEM), we have evaluated SE signals of an in-lens and an out-lens detector in LV-SEM. From the energy distribution spectra of SEs with various boosting voltages of the immersion lens system, we revealed that the electrostatic field of the immersion lens mainly collects electrons with energy lower than 40eV, acting as a low-pass filter. This effect is also observed as a contrast change in LV-SEM images taken by in-lens and out-lens detectors.

  14. An adjustable electron achromat for cathode lens microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Tromp, R.M., E-mail: rtromp@us.ibm.com [IBM T.J. Watson Research Center, 1101 Kitchawan Road, Yorktown Heights, NY 10598 (United States); Leiden Institute of Physics, Kamerlingh Onnes Laboratory, Niels Bohrweg 2, 2333 CA Leiden (Netherlands)

    2015-12-15

    Chromatic aberration correction in light optics began with the invention of a two-color-corrected achromatic crown/flint lens doublet by Chester Moore Hall in 1730. Such color correction is necessary because any single glass shows dispersion (i.e. its index of refraction changes with wavelength), which can be counteracted by combining different glasses with different dispersions. In cathode lens microscopes (such as Photo Electron Emission Microscopy – PEEM) we encounter a similar situation, where the chromatic aberration coefficient of the cathode lens shows strong dispersion, i.e. depends (non-linearly) on the energy with which the electrons leave the sample. Here I show how a cathode lens in combination with an electron mirror can be configured as an adjustable electron achromat. The lens/mirror combination can be corrected at two electron energies by balancing the settings of the electron mirror against the settings of the cathode lens. The achromat can be adjusted to deliver optimum performance, depending on the requirements of a specific experiment. Going beyond the achromat, an apochromat would improve resolution and transmission by a very significant margin. I discuss the requirements and outlook for such a system, which for now remains a wish waiting for fulfilment. - Highlights: • The properties of cathode objective lens plus electron mirror are discussed. • In analogy with light-optical achromats, cathode lens plus mirror can be configured as an electron achromat. • Unlike light optics, the electron achromat can be adjusted to best fulfill experimental requirements.

  15. Polarization response of RHIC electron lens lattices

    Directory of Open Access Journals (Sweden)

    V. H. Ranjbar

    2016-10-01

    Full Text Available Depolarization response for a system of two orthogonal snakes at irrational tunes is studied in depth using lattice independent spin integration. In particular we consider the effect of overlapping spin resonances in this system, to understand the impact of phase, tune, relative location and threshold strengths of the spin resonances. These results are benchmarked and compared to two dimensional direct tracking results for the RHIC e-lens lattice and the standard lattice. Finally we consider the effect of longitudinal motion via chromatic scans using direct six dimensional lattice tracking.

  16. Search for electroweak top quark production in the electron + jets channel in the D0 experiment at the Tevatron

    Energy Technology Data Exchange (ETDEWEB)

    Busato, Emmanuel [Paris Univ. (France)

    2005-04-01

    The top quark, whose mass approaches the electroweak symmetry breaking scale, is by far the heaviest known elementary particle. New physics is therefore expected to have its most important effect in the top sector. The Tevatron is, currently, the only collider able to produce the top quark. Among all possible production processes in the standard model, the top-antitop pair production via strong interaction, first observed in 1995, is the one with the largest cross section. The production via electroweak interaction (known as single top production), more difficult to extract from the background because of a lower cross section and of a lower signal to background ratio, has never been observed. In this thesis, we have searched for these processes by studying proton-antiproton collisions at $\\sqrt{s}$ =1.96 TeV produced by the Tevatron and detected with the DØ detector. The experimental study of the top quark is very sensitive to the quality of the data taken by the calorimeter. This detector showed, at the beginning of the Run II, rather important noise problems. Having identified the origin of the noise, new treatments at the offline level were implemented and their effects studied. It has been shown that these treatments reduce very significantly the effect of the noise in the reconstruction of physical quantities without notable degradation of the signal. Within the standard model, the top quark decays into W b with a branching ratio close to 100%. Leptonic decays of the into electron + neutrino have been used to identify the from the top decay. The main backgrounds to the single top signal ( +jets and QCD) are made essentially of light quark jets in the final state. Two ..-tagging algorithms have therefore been applied in order to improve the signal to background ratio. No evidence for electroweak top quark production has been found. Upper limits at the 95 % confidence level on the observed (expected) cross sections have be computed. They are found to be 14

  17. Thermomechanical Assessment of the Collector for the Hollow Electron Lens

    CERN Document Server

    Anderson, George Bowers

    2017-01-01

    The hollow electron lens (HEL) is a system proposed for the High Luminosity upgrade of the Large Hadron Collider LHC (HL-LHC) [1]. Being considered for installation at LHC point 4, the HEL improves halo control and collimation of proton beams in the collider [2]. This is achieved by creating a hollow tube of electrons using an electron gun. This axisymmetric electron cloud travels around the proton beam for a few meters, overlapping with the proton beam halo, until the electron cloud is dissipated in a collector, which is the focus of this project. A 3D image of the HEL system is found in Figure 1 and a further technical description of such electron lenses is available in [3].

  18. Preliminary Design Study of the Hollow Electron Lens for LHC

    CERN Document Server

    Perini, Diego; CERN. Geneva. ATS Department

    2017-01-01

    A Hollow Electron Lens (HEL) has been proposed in order to improve performance of halo control and collimation in the Large Hadron Collider in view of its High Luminosity upgrade (HL-LHC). The concept is based on a beam of electrons that travels around the protons for a few meters. The electron beam is produced by a cathode and then guided by a strong magnetic field generated by a set of superconducting solenoids. The first step of the design is the definition of the magnetic fields that drive the electron trajectories. The estimation of such trajectories by means of a dedicated MATLAB® tool is presented. The influence of the main geometrical and electrical parameters are analysed and discussed. Then, the main mechanical design choices for the solenoids, cryostats gun and collector are described. The aim of this paper is to provide an overview of the preliminary design of the Electron Lens for LHC. The methods used in this study also serve as examples for future mechanical and integration designs of similar ...

  19. Radial focusing of a relativistic electron beam in a bipotential electrostatic lens

    International Nuclear Information System (INIS)

    Genoni, T.C.

    1994-01-01

    The focusing of a relativistic electron beam in a bipotential electrostatic lens is discussed. An iterative scheme for the solution of the paraxial ray equation is used to derive approximate analytic formulas for the lens parameters and lens transfer matrix elements. The formulas are compared to results of direct numerical integration of the paraxial ray equation

  20. The effect of pipecol angles for the magnetic electron lens on the aberration coefficients

    International Nuclear Information System (INIS)

    Al-Khshab, A. M.; Al-Khshab, A. H.

    1997-01-01

    The symmetric mag etic objective lens of great importance for the electronic microscopes intended for hi g resolution. Such lens is determined, not only by its geometries structure and shape parameters, but also by the influence of the variation of the pole piece angles. the results show that the Objective lens having the pole piece angle of 55 a has a considerable effect on the electron optical Properties. When this pole piece is appropriately and highly saturated, the lens possesses low spherical and chromatic aberration coefficients. This hind of pole piece lens leads to more favourable design than other lenses. (authors). 14 refs., 7 figs.1 table

  1. Analysis of magnetic electron lens with secant hyperbolic field distribution

    International Nuclear Information System (INIS)

    Pany, S.S.; Ahmed, Z.; Dubey, B.P.

    2014-01-01

    Electron-optical imaging instruments like Scanning Electron Microscope (SEM) and Transmission Electron Microscope (TEM) use specially designed solenoid electromagnets for focusing of the electron beam. Indicators of imaging performance of these instruments, like spatial resolution, have a strong correlation with the focal characteristics of the magnetic lenses, which in turn have been shown to be sensitive to the details of the spatial distribution of the axial magnetic field. Owing to the complexity of designing practical lenses, empirical mathematical expressions are important to obtain the desired focal properties. Thus the degree of accuracy of such models in representing the actual field distribution determines accuracy of the calculations and ultimately the performance of the lens. Historically, the mathematical models proposed by Glaser [1] and Ramberg [2] have been extensively used. In this paper the authors discuss another model with a secant-hyperbolic type magnetic field distribution function, and present a comparison between models, utilizing results from finite element-based field simulations as the reference for evaluating performance

  2. Research for the boson of Higgs and for couplings of capacity quartic abnormal in the channel WW in electrons in the experiment D0 in Tevatron

    International Nuclear Information System (INIS)

    Chapon, Emilien

    2013-01-01

    Two physics analyzes are presented in this thesis, both probing the electroweak sector of the Standard Model using events with two oppositely charged electrons and missing transverse energy. The events are selected from the full Run II data sample of 9.7 fb -1 of proton-antiproton collisions collected with the D0 detector at the Fermilab Tevatron Collider at √s=1.96 TeV. The first analysis is a search for the Higgs boson in H → WW → evev decays. To validate the search methodology, the non-resonant WW production cross section is measured. In the Higgs boson search, no significant excess above the background expectation is observed. Upper limits on the Higgs boson production cross section are therefore derived, within the Standard Model, but also within a theoretical framework with a fourth generation of fermions, and in the context of fermiophobic Higgs boson couplings. A search for anomalous quartic gauge couplings between the photon and the W boson is then presented, using exclusive W boson pair production, allowing to probe new physics effects. The selection of the events and the analysis techniques used are mostly identical to those used in the first analysis, the search for the Higgs boson. The limits set on this type of anomalous couplings are the first ones from the Tevatron and the most stringent ones at the time of the publication. (author) [fr

  3. Tevatron Beam Position Monitor Upgrade

    CERN Document Server

    Wolbers, Stephen; Barker, B; Bledsoe, S; Boes, T; Bowden, Mark; Cancelo, Gugstavo I; Dürling, G; Forster, B; Haynes, B; Hendricks, B; Kasza, T; Kutschke, Robert K; Mahlum, R; Martens, Michael A; Mengel, M; Olsen, M; Pavlicek, V; Pham, T; Piccoli, Luciano; Steimel, Jim; Treptow, K; Votava, Margaret; Webber, Robert C; West, B; Zhang, D

    2005-01-01

    The Tevatron Beam Position Monitor (BPM) readout electronics and software have been upgraded to improve measurement precision, functionality and reliability. The original system, designed and built in the early 1980s, became inadequate for current and future operations of the Tevatron. The upgraded system consists of 960 channels of new electronics to process analog signals from 240 BPMs, new front-end software, new online and controls software, and modified applications to take advantage of the improved measurements and support the new functionality. The new system reads signals from both ends of the existing directional stripline pickups to provide simultaneous proton and antiproton position measurements. Measurements using the new system are presented that demonstrate its improved resolution and overall performance.

  4. Celebrating the Tevatron legacy

    CERN Multimedia

    2012-01-01

    Fermilab hosted an exceptional event on 11 June: the Tevatron Impact symposium. More than 800 people attended to hear how the Tevatron advanced our understanding of fundamental physics.   A version of this "Director's Corner" by Pier Oddone first appeared in Fermilab Today on 12 June.   The development of accelerator technology for the Tevatron has influenced every subsequent major hadron accelerator. We heard reviews on the detector technologies and trigger systems developed with the Tevatron that are essential today for high-luminosity machines like the LHC. There were also talks on the superconducting-wire industry that made MRI magnets ubiquitous, and we discussed the major computational systems that use large farms of Linux-based commodity processors. Researchers who worked on the Tevatron also established multivariate analysis techniques that now allow us to squeeze the maximum information from complex data sets. One focus of the symposium was the ...

  5. Coupling in the Tevatron

    International Nuclear Information System (INIS)

    Gelfand, N.M.

    1994-12-01

    The performance of the Fermilab Tevatron Collider at the commencement of run Ib was far below expectations. After a frustrating period of several months, a low-β quad downstream of the interaction point at B0 was found to be rolled. This rolled quadrupole coupled the horizontal and vertical motion of the Tevatron beams. It also made matching the beam from the Main Ring to the Tevatron impossible, resulting in emittance blow up on injection. The net result of the roll was a significant reduction in the Tevatron luminosity. When the roll in the quadrupole was corrected the performance of the Tevatron improved dramatically. This note will discuss the experimental data indicating the presence of coupling and subsequent calculations which show how coupling an affect the luminosity. It is not intended to exhaust a discussion of coupling, which hopefully will be understood well enough to be discussed in a subsequent note

  6. Coupling in the Tevatron

    Energy Technology Data Exchange (ETDEWEB)

    Gelfand, N.M.

    1994-12-01

    The performance of the Fermilab Tevatron Collider at the commencement of run Ib was far below expectations. After a frustrating period of several months, a low-{beta} quad downstream of the interaction point at B0 was found to be rolled. This rolled quadrupole coupled the horizontal and vertical motion of the Tevatron beams. It also made matching the beam from the Main Ring to the Tevatron impossible, resulting in emittance blow up on injection. The net result of the roll was a significant reduction in the Tevatron luminosity. When the roll in the quadrupole was corrected the performance of the Tevatron improved dramatically. This note will discuss the experimental data indicating the presence of coupling and subsequent calculations which show how coupling an affect the luminosity. It is not intended to exhaust a discussion of coupling, which hopefully will be understood well enough to be discussed in a subsequent note.

  7. Optimized lens-sparing treatment of retinoblastoma with electron beams

    NARCIS (Netherlands)

    Steenbakkers, RJHM; Altschuler, MD; DAngio, GJ; Goldwein, JW; Kassaee, A

    1997-01-01

    Purpose: The ideal lens-sparing radiotherapy technique for retinoblastoma calls for 100% dose to the entire retina including the ora serrata and zero dose to the lens, Published techniques, most of which use photons, have not accomplished this ideal treatment. We describe here a technique that

  8. Tevatron lower temperature operation

    International Nuclear Information System (INIS)

    Theilacker, J.C.

    1994-07-01

    This year saw the completion of three accelerator improvement projects (AIP) and two capital equipment projects pertaining to the Tevatron cryogenic system. The projects result in the ability to operate the Tevatron at lower temperature, and thus higher energy. Each project improves a subsystem by expanding capabilities (refrigerator controls), ensuring reliability (valve box, subatmospheric hardware, and compressor D), or enhancing performance (cold compressors and coldbox II). In January of 1994, the Tevatron operated at an energy of 975 GeV for the first time. This was the culmination, of many years of R ampersand D, power testing in a sector (one sixth) of the Tevatron, and final system installation during the summer of 1993. Although this is a modest increase in energy, the discovery potential for the Top quark is considerably improved

  9. Evaluation of lens dose from anterior electron beams: comparison of Pinnacle and Gafchromic EBT3 film.

    Science.gov (United States)

    Sonier, Marcus; Wronski, Matt; Yeboah, Collins

    2015-03-08

    Lens dose is a concern during the treatment of facial lesions with anterior electron beams. Lead shielding is routinely employed to reduce lens dose and minimize late complications. The purpose of this work is twofold: 1) to measure dose pro-files under large-area lead shielding at the lens depth for clinical electron energies via film dosimetry; and 2) to assess the accuracy of the Pinnacle treatment planning system in calculating doses under lead shields. First, to simulate the clinical geometry, EBT3 film and 4 cm wide lead shields were incorporated into a Solid Water phantom. With the lead shield inside the phantom, the film was positioned at a depth of 0.7 cm below the lead, while a variable thickness of solid water, simulating bolus, was placed on top. This geometry was reproduced in Pinnacle to calculate dose profiles using the pencil beam electron algorithm. The measured and calculated dose profiles were normalized to the central-axis dose maximum in a homogeneous phantom with no lead shielding. The resulting measured profiles, functions of bolus thickness and incident electron energy, can be used to estimate the lens dose under various clinical scenarios. These profiles showed a minimum lead margin of 0.5 cm beyond the lens boundary is required to shield the lens to ≤ 10% of the dose maximum. Comparisons with Pinnacle showed a consistent overestimation of dose under the lead shield with discrepancies of ~ 25% occur-ring near the shield edge. This discrepancy was found to increase with electron energy and bolus thickness and decrease with distance from the lead edge. Thus, the Pinnacle electron algorithm is not recommended for estimating lens dose in this situation. The film measurements, however, allow for a reasonable estimate of lens dose from electron beams and for clinicians to assess the lead margin required to reduce the lens dose to an acceptable level.

  10. Calcium and its localization in human lens fibres: an electron tomographic study

    NARCIS (Netherlands)

    Vanmarle, J.; Jonges, R.; Vrensen, G. F.; Dewolf, A.

    1997-01-01

    The ultrastructural distribution of calcium was studied in human lens fibres with the oxalate pyroantimonate technique. In the intermediate cortex precipitates were found perimembranous and occasionally in the fibre cytoplasm. The improved resolution of electron tomography revealed (a) that the

  11. Magnetic lens apparatus for use in high-resolution scanning electron microscopes and lithographic processes

    Science.gov (United States)

    Crewe, Albert V.

    2000-01-01

    Disclosed are lens apparatus in which a beam of charged particlesis brought to a focus by means of a magnetic field, the lens being situated behind the target position. In illustrative embodiments, a lens apparatus is employed in a scanning electron microscopeas the sole lens for high-resolution focusing of an electron beam, and in particular, an electron beam having an accelerating voltage of from about 10 to about 30,000 V. In one embodiment, the lens apparatus comprises an electrically-conducting coil arranged around the axis of the beam and a magnetic pole piece extending along the axis of the beam at least within the space surrounded by the coil. In other embodiments, the lens apparatus comprises a magnetic dipole or virtual magnetic monopole fabricated from a variety of materials, including permanent magnets, superconducting coils, and magnetizable spheres and needles contained within an energy-conducting coil. Multiple-array lens apparatus are also disclosed for simultaneous and/or consecutive imaging of multiple images on single or multiple specimens. The invention further provides apparatus, methods, and devices useful in focusing charged particle beams for lithographic processes.

  12. Physics at the Tevatron

    Energy Technology Data Exchange (ETDEWEB)

    Field, Rick; /Florida U.

    2006-04-01

    The theme of the XXXIV International Meeting on Fundamental Physics held in El Escorial, Spain on April 2-7, 2006 was ''From HERA and the TEVATRON to the LHC''. This is a summary of the four lectures I presented on ''Physics at the Tevatron''. Heavy quark production and the production of photons, bosons, and jets at the Tevatron are discussed. Also, a detailed study at the ''underlying event'' at CDF is presented together with a discussion of PYTHIA 6.2 tunes. A look back at the ''old days'' of Feynman-Field collider phenomenology is included.

  13. Tevatron physics results

    CERN Multimedia

    CERN. Geneva

    2007-01-01

    I will summarize the physics results from the Tevatron experiments with particular emphasis on the experimental methods used in different kinds of analysis. In particular, the Tevatron is a proton-antiproton collider that has now accumulated more than 2 fb^-1 of luminosity in the two experiments, called CDF and D0. In this lecture I will review the results on inclusive productions of jets, W- and Z-bosons, the results in the flavor sector, the measurements of top production, searches for Higgs boson production and searches for physics beyond the Standard Model. In each case I will explain the basic experimental concepts and methods needed for making the measurement.

  14. Tevatron Collider physics

    International Nuclear Information System (INIS)

    Eichten, E.J.

    1990-02-01

    The physics of hadron colliders is briefly reviewed. Issues for further study are presented. Particular attention is given to the physics opportunities for a high luminosity (≥ 100 pb -1 /experiment/run) Upgrade of the Tevatron Collider. 25 refs., 10 figs., 2 tabs

  15. Tevatron's complex collider cousins

    CERN Multimedia

    Fischer, W

    2004-01-01

    Letter referring to Schwarzschild's story "Disappointing performance and tight budgets confront Fermilab with tough decisions" and contesting that the Tevatron is not the most complex accelerator operating. They use the examples of CERN's SPS collider, HERA at DESY and the RHIC at Brookhaven (1/4 page)

  16. Measurements of beam halo diffusion and population density in the Tevatron and in the Large Hadron Collider

    CERN Document Server

    Stancari, Giulio

    Halo dynamics influences global accelerator performance: beam lifetimes, emittance growth, dynamic aperture, and collimation efficiency. Halo monitoring and control are also critical for the operation of high-power machines. For instance, in the high-luminosity upgrade of the LHC, the energy stored in the beam tails may reach several megajoules. Fast losses can result in superconducting magnet quenches, magnet damage, or even collimator deformation. The need arises to measure the beam halo and to remove it at controllable rates. In the Tevatron and in the LHC, halo population densities and diffusivities were measured with collimator scans by observing the time evolution of losses following small inward or outward collimator steps, under different experimental conditions: with single beams and in collision, and, in the case of the Tevatron, with a hollow electron lens acting on a subset of bunches. After the LHC resumes operations, it is planned to compare measured diffusivities with the known strength of tran...

  17. Effect of pulsed hollow electron-lens operation on the proton beam core in LHC

    Energy Technology Data Exchange (ETDEWEB)

    Fitterer, Miriam [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Stancari, Giulio [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Valishev, Alexander [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)

    2016-11-08

    Collimation with hollow electron beams is currently one of the most promising concepts for active halo control in the HL-LHC. In order to further increase the diffusion rates for a fast halo removal as e.g. desired before the squeeze, the electron lens (e-lens) can be operated in pulsed mode. In case of profile imperfections in the electron beam the pulsing of the e-lens induces noise on the proton beam which can, depending on the frequency content and strength, lead to emittance growth. In order to study the sensitivity to the pulsing pattern and the amplitude, a beam study (machine development MD) at the LHC has been proposed for August 2016 and we present in this note the preparatory simulations and estimates.

  18. Supersymmetry at the Tevatron?

    International Nuclear Information System (INIS)

    Lammel, S.

    1998-02-01

    These lectures contain an introduction to the search for supersymmetry at hadron colliders. The Tevatron is one of high-energy physics most sophisticated tools. The high center-of-mass energy of its proton-antiproton collisions makes it an ideal place to search for physics beyond the Standard Model, such as supersymmetry. Two experiments, CDF and D0, completed a long data taking period in summer of 1995, yielding over 100 pb -1 of proton-antiproton interactions. The data recorded by the experiments are still being analyzed. The lectures outline the strategies in the search for supersymmetry at the Tevatron and examine the major analyses in detail. Results obtained by the two experiments are included where available

  19. The tevatron energy doubler

    International Nuclear Information System (INIS)

    Edwards, H.T.

    1985-01-01

    The Tevatron project is a massive upgrade of the original Fermilab accelerator complex, which became operational in 1972 and operated from 1973 until mid-1982 at typically 400 GeV and 2 x 10/sup 13/ protons per pulse (ppp). The three parts of the Tevatron project when complete will allow for both fixed-target and collider hadron physics using primary beam energies in the 800-1000 GeV range. The Fermilab facility should thus be able to maintain its position at the forefront of high-energy physics research facilities. This paper describes the superconducting accelerator phase of the program Because the new synchrotron provides protons with twice the energy of the old Main Ring, it is frequently called the Energy Doubler. It first accelerated a beam in July 1983 and is presently operating at 800 GeV with intensities above 1 x 10/sup 13/ ppp

  20. Tevatron improvement program

    International Nuclear Information System (INIS)

    Wilson, R.R.

    1983-07-01

    A modest Tevatron improvement program is suggested which would provide a storage ring for dedicated use as a p anti p collider at 2 TeV (cm) and as an ep collider at 0.2 TeV (cm). It could also serve as a useful test facility for some of the new developments necessary for an economical SSC. Because use could be made of utilities and facilities that are already installed as part of the tevatron, the cost of the p anti p option might be about 100 million dollars (not including the interaction halls or detectors). The additional cost of a 10 x 1000 GeV' ep option might be about 70 million dollars. The experimental facilities at B and D of the Tevatron might be extended for use with the new collider. As the technology of superconducting magnets develops, the cm energy of the p anti p and the ep colliders might be doubled. The intention is either to double the capability of TeV I and TeV II, or to extend the capability by addition of an ep facility. Alternatively, by adding another proton ring, a high luminosity pp facility might also result

  1. Tevatron improvement program

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, R.R.

    1983-07-01

    A modest Tevatron improvement program is suggested which would provide a storage ring for dedicated use as a p anti p collider at 2 TeV (cm) and as an ep collider at 0.2 TeV (cm). It could also serve as a useful test facility for some of the new developments necessary for an economical SSC. Because use could be made of utilities and facilities that are already installed as part of the tevatron, the cost of the p anti p option might be about 100 million dollars (not including the interaction halls or detectors). The additional cost of a 10 x 1000 GeV' ep option might be about 70 million dollars. The experimental facilities at B and D of the Tevatron might be extended for use with the new collider. As the technology of superconducting magnets develops, the cm energy of the p anti p and the ep colliders might be doubled. The intention is either to double the capability of TeV I and TeV II, or to extend the capability by addition of an ep facility. Alternatively, by adding another proton ring, a high luminosity pp facility might also result.

  2. Pathological findings in the lens capsules and intraocular lens in chronic pseudophakic endophthalmitis: an electron microscopy study.

    Science.gov (United States)

    Adán, A; Casaroli-Marano, R P; Gris, O; Navarro, R; Bitrian, E; Pelegrin, L; Sanchez-Dalmau, B

    2008-01-01

    The aim of this study was to describe the pathological findings in lens capsules and intraocular lens (IOL) studied by scanning and/or transmission electron microscopy (SEM and TEM, respectively) in a series of four eyes with chronic pseudophakic endophthalmitis (CPE). We performed a retrospective study of four patients presenting CPE in whom surgical treatment with pars plana vitrectomy, capsulectomy with extraction of the IOL, and intravitreous antibiotic therapy was thereafter performed. The extracted IOL and the capsular remains were studied by SEM and/or TEM and microbiologic analysis of aqueous humour and vitreous aspirate was also carried out in all the cases. The presence of microorganisms was observed in the material analysed in all the cases studied. The use of TEM identified bacterial contamination by Staphylococcus spp and mixed contamination with microorganisms presenting a bacillar morphology suggestive of infection by Propionibacterium acnes in addition to the presence of cocci in the capsular remains. In another two cases, SEM localized colonies of Staphylococcus spp on the surface of the IOL in one case and mixed bacterial colonization with cocci plus filamentous bacteria in the other. The presence of macrophages associated with bacteria was observed in the capsular remains. Microorganisms were found in the IOL or the capsular material in the four cases studied, thereby explaining the refractoriness and severity of infection. The possible presence of polymicrobial infections, especially in the cases with filamentous bacteria, also explains the recurrence of infection.

  3. Electron Lens as Beam-Beam Wire Compensator in HL-LHC

    CERN Document Server

    Valishev, A

    2013-01-01

    Current wires are considered for compensation of long-range beam-beam interactions for the High Luminosity upgrade (HL-LHC) of the Large Hadron Collider at CERN. In this note, we demonstrate the advantage of using Electron Lens for this purpose instead of a conventional current-bearing wire.

  4. Variable magnification dual lens electron holography for semiconductor junction profiling and strain mapping.

    Science.gov (United States)

    Wang, Y Y; Li, J; Domenicucci, A; Bruley, J

    2013-01-01

    Dual lens operation for electron holography, which was developed previously (Wang et al., Ultramicroscopy 101 (2004) 63-72; US patent: 7,015,469 B2 (2006)), is re-investigated for bright field (junction profiling) and dark field (strain mapping) electron holography using FEI instrumentation (i.e. F20 and Titan). It is found that dual lens operation provides a wide operational range for electron holography. In addition, the dark field image tilt increases at high objective lens current to include Si diffraction spot. Under the condition of high spatial resolution (1 nm fringe spacing), a large field of view (450 nm), and high fringe contrast (26%) with dual lens operation, a junction map is obtained and strain maps of Si device on and diffraction are acquired. In this paper, a fringe quality number, N', which is number of fringe times fringe contrast, is proposed to estimate the quality of an electron hologram and mathematical reasoning for the N' number is provided. Copyright © 2012 Elsevier B.V. All rights reserved.

  5. Corrections of Magnification and Focusing in a Cathode Lens-Equipped Scanning Electron Microscope

    Czech Academy of Sciences Publication Activity Database

    Zobačová, Jitka; Zobač, Martin; Oral, Martin; Müllerová, Ilona; Frank, Luděk

    2006-01-01

    Roč. 28, č. 3 (2006), s. 155-163 ISSN 0161-0457 R&D Projects: GA AV ČR KJB2065301 Institutional research plan: CEZ:AV0Z20650511 Keywords : low-energy scanning electron microscopy (SEM) * cathode lens * critical dimension measurement in SEM * automatic corrections Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 0.462, year: 2006

  6. Consumer electronic optics: how small can a lens be: the case of panomorph lenses

    Science.gov (United States)

    Thibault, Simon; Parent, Jocelyn; Zhang, Hu; Du, Xiaojun; Roulet, Patrice

    2014-09-01

    In 2014, miniature camera modules are applied to a variety of applications such as webcam, mobile phone, automotive, endoscope, tablets, portable computers and many other products. Mobile phone cameras are probably one of the most challenging parts due to the need for smaller and smaller total track length (TTL) and optimized embedded image processing algorithms. As the technology is developing, higher resolution and higher image quality, new capabilities are required to fulfil the market needs. Consequently, the lens system becomes more complex and requires more optical elements and/or new optical elements. What is the limit? How small an injection molded lens can be? We will discuss those questions by comparing two wide angle lenses for consumer electronic market. The first lens is a 6.56 mm (TTL) panoramic (180° FOV) lens built in 2012. The second is a more recent (2014) panoramic lens (180° FOV) with a TTL of 3.80 mm for mobile phone camera. Both optics are panomorph lenses used with megapixel sensors. Between 2012 and 2014, the development in design and plastic injection molding allowed a reduction of the TTL by more than 40%. This TTL reduction has been achieved by pushing the lens design to the extreme (edge/central air and material thicknesses as well as lens shape). This was also possible due to a better control of the injection molding process and material (low birefringence, haze and thermal stability). These aspects will be presented and discussed. During the next few years, we don't know if new material will come or new process but we will still need innovative people and industries to push again the limits.

  7. Dose conversion coefficients for electron exposure of the human eye lens

    International Nuclear Information System (INIS)

    Behrens, R; Dietze, G; Zankl, M

    2009-01-01

    Recent epidemiological studies suggest a rather low dose threshold (below 0.5 Gy) for the induction of a cataract of the eye lens. Some other studies even assume that there is no threshold at all. Therefore, protection measures have to be optimized and current dose limits for the eye lens may be reduced in the future. Two questions arise from this situation: first, which dose quantity is related to the risk of developing a cataract, and second, which personal dose equivalent quantity is appropriate for monitoring this dose quantity. While the dose equivalent quantity H p (0.07) has often been seen as being sufficiently accurate for monitoring the dose to the lens of the eye, this would be questionable in the case when the dose limits were reduced and, thus, it may be necessary to generally use the dose equivalent quantity H p (3) for this purpose. The basis for a decision, however, must be the knowledge of accurate conversion coefficients from fluence to equivalent dose to the lens. This is especially important for low-penetrating radiation, for example, electrons. Formerly published values of conversion coefficients are based on quite simple models of the eye. In this paper, quite a sophisticated model of the eye including the inner structure of the lens was used for the calculations and precise conversion coefficients for electrons with energies between 0.2 MeV and 12 MeV, and for angles of radiation incidence between 0 deg. and 45 deg. are presented. Compared to the values adopted in 1996 by the International Commission on Radiological Protection (ICRP), the new values are up to 1000 times smaller for electron energies below 1 MeV, nearly equal at 1 MeV and above 4 MeV, and by a factor of 1.5 larger at about 1.5 MeV electron energy.

  8. Tevatron extraction microcomputer

    International Nuclear Information System (INIS)

    Chapman, L.; Finley, D.A.; Harrison, M.; Merz, W.; Batavia, IL)

    1985-01-01

    Extraction in the Fermilab Tevatron is controlled by a multi-processor Multibus microcomputer system called QXR (Quad eXtraction Regulator). QXR monitors several analog beam signals and controls three sets of power supplies: the ''bucker'' and ''pulse'' magnets at a rate of 5760 Hz, and the ''QXR'' magnets at 720 Hz. QXR supports multiple slow spills (up to a total of 35 seconds) with multiple fast pulses intermixed. It linearizes the slow spill and bucks out the high frequency components. Fast extraction is done by outputting a variable pulse waveform. Closed loop learning techniques are used to improve performance from cycle to cycle for both slow and fast extraction. The system is connected to the Tevatron clock system so that it can track the machine cycle. QXR is also connected to the rest of the Fermilab control system, ACNET. Through ACNET, human operators and central computers can monitor and control extraction through communications with QXR. The controls hardware and software both employ some standard and some specialized components. This paper gives an overview of QXR as a control system; another paper (1) summarizes performance

  9. Tevatron extraction microcomputer

    International Nuclear Information System (INIS)

    Chapman, L.; Finley, D.A.; Harrison, M.; Merz, W.

    1985-06-01

    Extraction in the Fermilab Tevatron is controlled by a multi-processor Multibus microcomputer system called QXR (Quad eXtraction Regulator). QXR monitors several analog beam signals and controls three sets of power supplies: the ''bucker'' and ''pulse'' magnets at a rate of 5760 Hz, and the ''QXR'' magnets at 720 Hz. QXR supports multiple slow spills (up to a total of 35 seconds) with multiple fast pulses intermixed. It linearizes the slow spill and bucks out the high frequency components. Fast extraction is done by outputting a variable pulse waveform. Closed loop learning techniques are used to improve performance from cycle to cycle for both slow and fast extraction. The system is connected to the Tevatron clock system so that it can track the machine cycle. QXR is also connected to the rest of the Fermilab control system, ACNET. Through ACNET, human operators and central computers can monitor and control extraction through communications with QXR. The controls hardware and software both employ some standard and some specialized components. This paper gives an overview of QXR as a control system; another paper summarizes performance

  10. Stretchable Electronic Platform for Soft and Smart Contact Lens Applications

    OpenAIRE

    Vasquez Quintero, Andrés Felipe; Verplancke, Rik; De Smet, Herbert; Vanfleteren, Jan

    2017-01-01

    A stretchable platform with spherical-shaped electronics based on thermo- plastic polyurethane (TPU) is introduced for soft smart contact lenses. The low glass transition temperature of TPU, its relatively low hardness, and its proven biocompatibility (i.e., protection of exterior body wounds) fulfill the essential requirements for eye wearable devices. These requirements include optical transparency, conformal fitting, and flexibility comparable with soft contact lense...

  11. Recent results from the Tevatron

    Energy Technology Data Exchange (ETDEWEB)

    Vellidis, Costas; Bravina, L.; Foka, Y.; Kabana, S.

    2015-01-01

    The Tevatron p$\\bar{p}$ collider was shut down in 2011, after 10 years of high performance operation at a center-of-mass energy √s = 1.96 TeV in Run II. The two experiments, CDF and DZero, continue to analyze the collected data, aiming to extract all possible information regarding studies of the standard model and searches for new physics. A short review of some of the recent measurements at the Tevatron, and of the impact of the Tevatron program to high energy physics, is presented.

  12. A magnetic lens electron spectrometer with simultaneous momentum and energy selection

    International Nuclear Information System (INIS)

    Julin, R.; Kantele, J.; Passoja, A.

    1975-01-01

    A preliminary version of a combined swept-current magnetic lens plus Si(Li) electron spectrometer with simultaneous momentum and energy selection is presented. Results from test runs indicate that the spectrometer will be featuring good energy resolution and line shape, moderate transmission, and low background. The spectrometer is intended for in-beam measurements of conversion electron lines up to several MeV in energy and for nanosecond lifetime determinations, as well as for off-line studies of continuous beta-ray spectra and conversion lines from shortlived activities. (Auth.)

  13. Miniature electrostatic lens for generation of a low-voltage high current electron probe

    International Nuclear Information System (INIS)

    Bubeck, C.-D.; Fleischmann, A.; Knell, G.; Lutsch, R.Y.; Plies, E.; Winkler, D.

    1999-01-01

    A miniature tetrode system, according to F. Burstert, D. Winkler and B. Lischke [Microelectron. Eng. 31 (1996) 95], for the generation of a low-voltage electron probe was investigated and further developed. The tetrode system consists of a Schottky cathode and a miniaturized lens, composed of three conventional electron microscopical apertures, which are used as electrodes. We tested two configurations with different aperture thicknesses and bore diameters experimentally and also made simulations of these lenses. Two kinds of middle electrodes, a flat and a top-hat aperture, were used. In most cases the experimental data show a good agreement with the theoretically predicted values of the examined tetrode system

  14. Preliminary Mechanical Design Study of the Hollow Electron Lens for HL-LHC

    Energy Technology Data Exchange (ETDEWEB)

    Zanoni, Carlo [CERN; Gobbi, Giorgia [CERN; Perini, Diego [CERN; Stancari, Giulio [Fermilab

    2017-05-01

    A Hollow Electron Lens (HEL) has been proposed in order to improve performance of halo control and collimation in the Large Hadron Collider in view of its High Luminosity upgrade (HL-LHC). The concept is based on a hollow beam of electrons that travels around the protons for a few meters. The electron beam is produced by a cathode and then guided by a strong magnetic field. The first step of the design is the definition of the magnetic field that drives the electron trajectories. The estimation of such trajectories by means of a dedicated MATLAB tool is presented. The influence of the main geometrical and electrical parameters is analyzed and discussed. Then, the main mechanical design choices for the solenoids, cryostats gun and collector are described. The aim of this paper is to provide an overview of the feasibility study of the Electron Lens for LHC. The methods used in this study also serve as examples for future mechanical and integration designs of similar devices.

  15. Preliminary Mechanical Design Study of the Hollow Electron Lens for HL-LHC

    Science.gov (United States)

    Zanoni, Carlo; Gobbi, Giorgia; Perini, Diego; Stancari, Giulio

    2017-07-01

    A Hollow Electron Lens (HEL) has been proposed in order to improve performance of halo control and collimation in the Large Hadron Collider in view of its High Luminosity upgrade (HL-LHC). The concept is based on a hollow beam of electrons that travels around the protons for a few meters. The electron beam is produced by a cathode and then guided by a strong magnetic field. The first step of the design is the definition of the magnetic field that drives the electron trajectories. The estimation of such trajectories by means of a dedicated MATLAB tool is presented. The influence of the main geometrical and electrical parameters is analyzed and discussed. Then, the main mechanical design choices for the solenoids, cryostats gun and collector are described. The aim of this paper is to provide an overview of the feasibility study of the Electron Lens for LHC. The methods used in this study also serve as examples for future mechanical and integration designs of similar devices.

  16. A magnetized Einzel lens electron dump for the Linac4 H− ion source

    CERN Document Server

    Midttun, O; Kronberger, M; Lettry, J; Pereira, H; Scrivens, R

    2013-01-01

    Linac4 is a 160 MeV linear accelerator which will inject negative hydrogen ions (H−) into CERN’s Proton Synchrotron Booster, a required upgrade to improve the beam brightness in the LHC injector chain. A volume production RF ion source, based on the design of the DESY RF source was implemented, but showed considerable electron dump ablation during operation at 45 keV beam energy. To reduce the electron beam power density in the dump, a magnetized Einzel lens is designed that reduces the beam energy to 10 keV before permanentmagnets dump the electrons on a tungsten surface. Presented in this paper are simulations of the design using IBSimu, the tunable range of parameters depending on the extracted H− and electron current, as well as details of the implementation, the choice of pulsed power converters and the electrode alignment system. In addition, simulations of proton extraction from this source will be shown.

  17. eV-TEM: Transmission electron microscopy in a low energy cathode lens instrument

    Energy Technology Data Exchange (ETDEWEB)

    Geelen, Daniël, E-mail: geelen@physics.leidenuniv.nl [Huygens-Kamerlingh Onnes Laboratory, Leiden Institute of Physics, Leiden University, P.O. Box 9504, 2300 RA Leiden (Netherlands); Thete, Aniket [Huygens-Kamerlingh Onnes Laboratory, Leiden Institute of Physics, Leiden University, P.O. Box 9504, 2300 RA Leiden (Netherlands); Schaff, Oliver; Kaiser, Alexander [SPECS GmbH, Voltastrasse 5, D-13355 Berlin (Germany); Molen, Sense Jan van der [Huygens-Kamerlingh Onnes Laboratory, Leiden Institute of Physics, Leiden University, P.O. Box 9504, 2300 RA Leiden (Netherlands); Tromp, Rudolf [IBM T.J. Watson Research Center, 1101 Kitchawan Road, P.O. Box 218, Yorktown Heights, NY 10598 (United States)

    2015-12-15

    We are developing a transmission electron microscope that operates at extremely low electron energies, 0–40 eV. We call this technique eV-TEM. Its feasibility is based on the fact that at very low electron energies the number of energy loss pathways decreases. Hence, the electron inelastic mean free path increases dramatically. eV-TEM will enable us to study elastic and inelastic interactions of electrons with thin samples. With the recent development of aberration correction in cathode lens instruments, a spatial resolution of a few nm appears within range, even for these very low electron energies. Such resolution will be highly relevant to study biological samples such as proteins and cell membranes. The low electron energies minimize adverse effects due to radiation damage. - Highlights: • We present a new way of performing low energy transmission electron microscopy in an aberration corrected LEEM/PEEM instrument. • We show a proof of principle where we measure transmitted electrons through a suspended graphene monolayer with a preliminary setup. • We present an improved setup design that provides better control of the incident electron beam.

  18. HIGH-CURRENT COLD CATHODE FIELD EMISSION ARRAY FOR ELECTRON LENS APPLICATION

    Energy Technology Data Exchange (ETDEWEB)

    Hirshfield, Jay L

    2012-12-28

    During Phase I, the following goals were achieved: (1) design and fabrication of a novel, nano-dimensional CNT field emitter assembly for high current density application, with high durability; (2) fabrication of a ceramic based micro channel plate (MCP) and characterization of its secondary electron emission; and (3) characterizing the CNT/MCP cathode for high field emission and durability. As a result of these achievements, a relatively high current density of ~ 1.2 A/cm2 from a CNT cathode and single channel MCP were measured. The emission current was also extremely stable with a peak-to-peak variation of only 1.8%. The emission current could be further enhanced to meet requirements for electron lens applications by increasing the number of MCP channels. A calculation for maximum possible current density with a 1200 channel/cm2 MCP, placed over a cathode with 1200 uniformly functioning CNTs, would be ~1.46 kA/cm2, neglecting space charge limitations. Clearly this level of emission is far greater than what is needed for the electron lens application, but it does offer a highly comforting margin to account for sub-standard emitters and/or to allow the lesser challenge of building a cathode with fewer channels/cm2. A satisfactory goal for the electron lens application would be a controllable emission of 2-4 mA per channel in an ensemble of 800-1200 uniformly-functioning channels/cm2, and a cathode with overall area of about 1 cm2.

  19. SU-F-T-86: Electron Dosimetric Effects of Bolus and Lens Shielding in Treating Superficial Eye Lesions

    Energy Technology Data Exchange (ETDEWEB)

    Young, L [University of Washington Medical Center, Seattle, WA (United States); Wootton, L [University of Washington School of Medicine, Seattle, WA (United States); Gopan, O; Liao, J [University of Washington, Seattle, WA (United States)

    2016-06-15

    Purpose: Electron therapy for the treatment of ocular lymphomas requires the lens to be shielded to prevent secondary cataracts. This work evaluates the dosimetry under a suspended eyeshield with and without bolus for low energy electron fields. Methods: Film (GafChromic EBT3) dosimetry and relative output factors were measured for 6, 8, and 10 MeV electron energies. A customized 5 cm diameter circle electron orbital cutout was constructed for a 6×6 cm applicator with a lens shield, 1 cm diameter Cerrobend cylinder with 2.2 cm length, suspended from an XV film covering the open field. Relative output factors were measured using a Scanditronix electron diode in a solid water phantom. Depth dose profiles were collected for bolus thicknesses of 0, 3, and 5 mm in solid water at a source to surface distance (SSD) of 100 cm. These measurements were repeated in a Rando phantom. Results: At 5 mm, the approximate distance of the lens from the surface of the cornea, the estimated dose in solid water under the suspended lens shield was reduced to 16%, 14%, and 13% of the unblocked dose at the same depth, for electron energies of 6, 8, and 10 MeV, respectively. Applying bolus increased estimated doses under the block to 22% for 3-mm and 32% for 5-mm thicknesses for a 6 MeV incident electron beam. This effect is reduced for higher energies where the corresponding values were 15.5% and 18% for 3-mm and 5-mm for an 8 MeV electron beam. Conclusion: The application of bolus to treat superficial eye lesions of the conjunctiva increases lens dose at a depth of 5-mm under the shielding block with decreasing electron energy. Careful selection of electron energy is needed to account for electron scatter under the lens shield with the application of bolus in order to prevent cataracts.

  20. Antiproton production for Tevatron

    International Nuclear Information System (INIS)

    Azhgirey, I.L.; Mokhov, N.V.; Striganov, S.I.

    1991-03-01

    Needs to improve the Fermilab Pbar Source for the Tevatron Upgrade and discrepancies in predictions of the antiproton yields have forced us to develop the production model based on the modern data and to incorporate this model to the current version of MARS10 code. The inclusive scheme of this code with the use of statistical weights allows the production of antiprotons to be enhanced within the phase space region of interest, which is extremely effective for optimization of Pbar Source parameters and for developing of such an idea as a beam sweeping system. Antiproton production model included in the modified version of our Monte Carlo program MARS10M for the inclusive simulation of hadronic cascades, as for other particles throughout the program, is based on a factorization approach for hadron-nucleus differential cross-section. To describe antiproton inclusive spectra in pp-collisions a phenomenological model has been used modified in the low-Pt region. The antiproton production in pion-nucleon interactions is described in the frame of our simple phenomenological model based on the modern data. In describing of the of antiproton production cross-sections ratio in hadron-nucleus and hadron-nucleon collisions the ideas of soft hadronization of color strings and all the present experimental data have been used. Some comparisons of our model with experimental data are presented in the wide intervals of initial momenta, antiproton kinematical variables and nuclei. In all the cases the agreement is pretty good what gives us an assurance in the consequent studies carried out for the Fermilab Pbar Source. The results of such study are presented in this paper

  1. Electroweak physics at the Tevatron collider

    International Nuclear Information System (INIS)

    Aihara, H.

    1993-08-01

    Preliminary results on electroweak physics from the 1992--1993 run with the CDF and D0 detectors at the Tevatron collider are presented. New measurements of the ratio of the W and Z production cross sections times the branching fractions for subsequent decay into leptons are shown. The W width, Γ(W), and a limit on the top-quark mass independent of decay mode are extracted. The status of a measurement of the charge asymmetry of electrons from W decay is given. Also shown are a study of diboson (Wγ, Zγ and WZ) production and a search for a new neutral gauge boson (Z')

  2. DEVELOPMENT OF A COMPACT PHOTO-INJECTOR WITH RFFOCUSING LENS FOR SHORT PULSE ELECTRON SOURCE APPLICATION

    Energy Technology Data Exchange (ETDEWEB)

    Grabenhofer, Alexander [Northern Illinois University; Eaton, Douglas W. [ScandiNova systems AB, Uppsala, Sweden

    2013-09-01

    For development of compact ultrafast electron source system, we are currently designing a short-pulse RF-gun with RF focusing structure by means of a series of comprehensive modeling analysis processes. EM design of a 2.5 cell resonant cavity with input coupler, acceleration dynamics of photo-emitted electron bunch, EM design of RF-lens with input coupler, and phasespace analysis of focused electron bunch are systematically examined with multi-physics simulators. All the features of the 2.856 GHz cavity geometry were precisely engineered for acceleration energies ranging from 100 keV to 500 keV (safety limited) to be powered by our 5 MW S-band klystron. The klystron (Thales TH2163) and modulator system (ScandiNova K1 turnkey system) were successfully installed and tested. Performance tests of the klystron system show peak output power > 5 MW, as per operation specifications. At the quasi-relativistic energies, the electron source is capable of generating 100fC – 1 pC electron bunch with pulse duration close to 30 fs – 1 ps and transverse size of a few hundred microns. PIC simulations have shown that the electron bunch undergoes fast RF acceleration, rapidly reaching the desired energies, which can be controlled by tuning RF injection phase and input driving power. It has been shown that it is possible to also focus/compress the bunch longitudinally using a RF-lens, which would allow us to control the temporal resolution of the system as well. While our primary analysis has been performed on a 2.5 cell design, we are also looking into half-cell (single cavity) design that is expected to provide the same range of beam energy with a simple configuration.

  3. Conjunctival lymphoma: Results and treatment with a single anterior electron field. A lens sparing approach

    International Nuclear Information System (INIS)

    Dunbar, S.F.; Linggood, R.M.; Doppke, K.P.; Duby, A.; Wang, C.C.

    1990-01-01

    Lymphoma of the conjunctiva is rare. It presents in older patients as a mass lesion and usually remains localized. Surgery is limited to biopsy, and radiation therapy is the definitive treatment of choice. The entire conjunctiva is treated. Relatively high doses (approximately 30 Gy) are required for local control, which may lead to cataract formation. Twelve patients with conjunctival lymphoma were treated at the Massachusetts General Hospital between 1979 and 1988. Ten of 12 patients presented with a unilateral lesion; 2 of 12 with bilateral lesions. Two of 12 patients were found to have systemic disease at the time of presentation. One patient developed conjunctival lymphoma 5 years after the diagnosis of generalized disease. Using electron beam, all patients were treated with a single anterior circular field to total doses ranging from 24 Gy to 30 Gy delivered in 8 to 16 fractions over 9 to 20 days. In all cases, the lens was shielded by a specially designed plastic contact lens bearing a 12 mm diameter lead shield. The lens dose was determined at varying depths beneath the shield for 6 MeV and 9 MeV electron beams and ranged from a minimum of 5% to an absolute maximum of 18% of the total dose delivered to the tumor. Local control was maintained in all patients with follow-up to 9 1/2 years. One patient relapsed distantly 3 years after treatment. One of 12 patients died of systemic disease 4 years after treatment of the ocular lesion. Two patients developed cataracts 4 and 5 years after treatment; one had bilateral cataract, although only one eye had been treated. Both patients were over 75 years old. In both cases, the cataracts were felt to be senile cataracts which are ophthalmologically and radiographically distinguishable from radiation induced lesions

  4. Dose conversion coefficients for monoenergetic electrons incident on a realistic human eye model with different lens cell populations

    International Nuclear Information System (INIS)

    Nogueira, P; Vaz, P; Zankl, M; Schlattl, H

    2011-01-01

    The radiation-induced posterior subcapsular cataract has long been generally accepted to be a deterministic effect that does not occur at doses below a threshold of at least 2 Gy. Recent epidemiological studies indicate that the threshold for cataract induction may be much lower or that there may be no threshold at all. A thorough study of this subject requires more accurate dose estimates for the eye lens than those available in ICRP Publication 74. Eye lens absorbed dose per unit fluence conversion coefficients for electron irradiation were calculated using a geometrical model of the eye that takes into account different cell populations of the lens epithelium, together with the MCNPX Monte Carlo radiation transport code package. For the cell population most sensitive to ionizing radiation-the germinative cells-absorbed dose per unit fluence conversion coefficients were determined that are up to a factor of 4.8 higher than the mean eye lens absorbed dose conversion coefficients for electron energies below 2 MeV. Comparison of the results with previously published values for a slightly different eye model showed generally good agreement for all electron energies. Finally, the influence of individual anatomical variability was quantified by positioning the lens at various depths below the cornea. A depth difference of 2 mm between the shallowest and the deepest location of the germinative zone can lead to a difference between the resulting absorbed doses of up to nearly a factor of 5000 for electron energy of 0.7 MeV.

  5. Dose conversion coefficients for monoenergetic electrons incident on a realistic human eye model with different lens cell populations

    Energy Technology Data Exchange (ETDEWEB)

    Nogueira, P; Vaz, P [Technological and Nuclear Institute, Estrada Nacional No 10, 2686-953 Sacavem (Portugal); Zankl, M; Schlattl, H, E-mail: pedro.nogueira@helmholtz-muenchen.de [Helmholtz Zentrum Muenchen-German Research Center for Environmental Health, Research Unit Medical Radiation Physics and Diagnostics, Ingolstaedter Landstrasse 1, D-85764 Neuherberg (Germany)

    2011-11-07

    The radiation-induced posterior subcapsular cataract has long been generally accepted to be a deterministic effect that does not occur at doses below a threshold of at least 2 Gy. Recent epidemiological studies indicate that the threshold for cataract induction may be much lower or that there may be no threshold at all. A thorough study of this subject requires more accurate dose estimates for the eye lens than those available in ICRP Publication 74. Eye lens absorbed dose per unit fluence conversion coefficients for electron irradiation were calculated using a geometrical model of the eye that takes into account different cell populations of the lens epithelium, together with the MCNPX Monte Carlo radiation transport code package. For the cell population most sensitive to ionizing radiation-the germinative cells-absorbed dose per unit fluence conversion coefficients were determined that are up to a factor of 4.8 higher than the mean eye lens absorbed dose conversion coefficients for electron energies below 2 MeV. Comparison of the results with previously published values for a slightly different eye model showed generally good agreement for all electron energies. Finally, the influence of individual anatomical variability was quantified by positioning the lens at various depths below the cornea. A depth difference of 2 mm between the shallowest and the deepest location of the germinative zone can lead to a difference between the resulting absorbed doses of up to nearly a factor of 5000 for electron energy of 0.7 MeV.

  6. Dose conversion coefficients for monoenergetic electrons incident on a realistic human eye model with different lens cell populations.

    Science.gov (United States)

    Nogueira, P; Zankl, M; Schlattl, H; Vaz, P

    2011-11-07

    The radiation-induced posterior subcapsular cataract has long been generally accepted to be a deterministic effect that does not occur at doses below a threshold of at least 2 Gy. Recent epidemiological studies indicate that the threshold for cataract induction may be much lower or that there may be no threshold at all. A thorough study of this subject requires more accurate dose estimates for the eye lens than those available in ICRP Publication 74. Eye lens absorbed dose per unit fluence conversion coefficients for electron irradiation were calculated using a geometrical model of the eye that takes into account different cell populations of the lens epithelium, together with the MCNPX Monte Carlo radiation transport code package. For the cell population most sensitive to ionizing radiation-the germinative cells-absorbed dose per unit fluence conversion coefficients were determined that are up to a factor of 4.8 higher than the mean eye lens absorbed dose conversion coefficients for electron energies below 2 MeV. Comparison of the results with previously published values for a slightly different eye model showed generally good agreement for all electron energies. Finally, the influence of individual anatomical variability was quantified by positioning the lens at various depths below the cornea. A depth difference of 2 mm between the shallowest and the deepest location of the germinative zone can lead to a difference between the resulting absorbed doses of up to nearly a factor of 5000 for electron energy of 0.7 MeV.

  7. Neural networks at the Tevatron

    International Nuclear Information System (INIS)

    Badgett, W.; Burkett, K.; Campbell, M.K.; Wu, D.Y.; Bianchin, S.; DeNardi, M.; Pauletta, G.; Santi, L.; Caner, A.; Denby, B.; Haggerty, H.; Lindsey, C.S.; Wainer, N.; Dall'Agata, M.; Johns, K.; Dickson, M.; Stanco, L.; Wyss, J.L.

    1992-10-01

    This paper summarizes neural network applications at the Fermilab Tevatron, including the first online hardware application in high energy physics (muon tracking): the CDF and DO neural network triggers; offline quark/gluon discrimination at CDF; ND a new tool for top to multijets recognition at CDF

  8. Tau identification at the Tevatron

    Energy Technology Data Exchange (ETDEWEB)

    Levy, Stephen; /Chicago U., EFI

    2005-07-01

    Methods for reconstructing and identifying the hadronic decays of tau leptons with the CDF and D0 detectors at the Fermilab Tevatron collider in Run II are described. Precision electroweak measurements of W and Z gauge boson cross sections are presented as well as results of searches for physics beyond the Standard Model with hadronically decaying tau leptons in the final state.

  9. Higgs searches at the Tevatron

    Energy Technology Data Exchange (ETDEWEB)

    Qizhong Li

    2003-06-10

    One of the highest priority physics goals for the upgraded Tevatron experiments, CDF and D0, is the search for the Higgs boson. We present the initial results from both experiments, based on 40-90 pb{sup -1} integrated luminosity, of Higgs searches in several final states, including WH and ZH, H {yields} WW, and doubly-charged Higgs.

  10. Achievements and Lessons from Tevatron

    Energy Technology Data Exchange (ETDEWEB)

    Shiltsev, V.; /Fermilab

    2011-01-01

    For almost a quarter of a century, the Tevatron proton-antiproton collider was the centerpiece of the world's high energy physics program - beginning operation in December of 1985 until it was overtaken by LHC in 2011. The aim of the this unique scientific instrument was to explore the elementary particle physics reactions with center of mass collision energies of up to 1.96 TeV. The initial design luminosity of the Tevatron was 10{sup 30} cm{sup -2}s{sup -1}, however as a result of two decades of upgrades, the accelerator has been able to deliver 430 times higher luminosities to each of two high luminosity experiments, CDF and D0. Tevatron will be shut off September 30, 2011. The collider was arguably one of the most complex research instruments ever to reach the operation stage and is widely recognized for many technological breakthroughs and numerous physics discoveries. Below we briefly present the history of the Tevatron, major advances in accelerator physics, and technology implemented during the long quest for better and better performance. We also discuss some lessons learned from our experience.

  11. Luminosity lifetime in the Tevatron

    International Nuclear Information System (INIS)

    Jackson, G.; Finley, D.; Johnson, R.P.; Kerns, Q.; McCarthy, J.; Siemann, R.; Zhang, P.

    1988-01-01

    Since the inauguration of colliding proton-antiproton operations in 1987, the Tevatron has exhibited luminosity lifetimes shorter than expected. During a typical colliding beam storage period, called a store, luminosity is calculated periodically by measuring the charge and emittances of each bunch. The growth of the transverse bunch emittances is the dominant cause of luminosity deterioration. Throughout, this period, the position spectrum of the bunches exhibited betatron signals larger than expected from Schottky noise. A model assuming externally driven betatron oscillations explains both the betatron signals and the emittance growth. A program is underway to improve the Tevatron luminosity lifetime. The abort kickers have been identified as sources of emittance growth, and some quadrupole power supplies are further candidates. Because the horizontal dispersion through the RF cavities is nonzero, RF phase noise has been investigated. Noise in the main dipole regulation circuit has also been studied. 13 refs., 4 figs

  12. Accelerating polarized beams in Tevatron

    International Nuclear Information System (INIS)

    Teng, L.C.

    1989-02-01

    In this paper, we will examine the totality of equipment, manpower and cost necessary to obtain a polarized proton beam in the Tevatron. We will not, however, be concerned with the acquisition and acceleration of polarized /bar p/ beams. Furthermore we will consider only a planar main ring without overpass, although it is expected that Siberian snake schemes could be made to apply equally well to non-planar machines. In addition to not wanting to tackle here the task of reformulating the theory for a non-planar closed orbit, we also anticipate that as part of the Tevatron upgrade the main ring will in the not too distant future, be replaced by a planar main injector situated in a separate tunnel. 4 refs., 11 figs., 1 tab

  13. Tevatron serial data repeater system

    International Nuclear Information System (INIS)

    Ducar, R.J.

    1981-01-01

    A ten megabit per second serial data repeater system has been developed for the 6.28km Tevatron accelerator. The repeaters are positioned at each of the thirty service buildings and accommodate control and abort system communications as well as distribution of the Tevatron time and energy clocks. The repeaters are transparent to the particular protocol of the transmissions. Serial data are encoded locally as unipolar two volt signals employing the self-clocking Manchester Bi-Phase code. The repeaters modulate the local signals to low-power bursts of 50 MHz rf carrier for the 260m transmission between service buildings. The repeaters also demodulate the transmission and restructure the data for local utilization. The employment of frequency discrimination techniques yields high immunity to the characteristic noise spectrum

  14. Electroweak results from the tevatron

    Energy Technology Data Exchange (ETDEWEB)

    Wood, D. [Fermi National Accelerator Laboratory, Batavia, IL (United States)

    1997-01-01

    Electroweak results are presented from the CDF and DO experiments based on data collected in recent runs of the Fermilab Tevatron Collider. The measurements include the mass and width of the W boson, the production cross sections of the W and Z bosons, and the W charge asymmetry. Additional results come from studies of events with pairs of electroweak gauge bosons and include limits on anomalous couplings.

  15. B physics at the Tevatron

    International Nuclear Information System (INIS)

    Morello, M.J.

    2011-01-01

    The CDF and DO experiments at the Tevatron pp collider established that extensive and detailed exploration of the b-quark dynamics is possible in hadron collisions, with results competitive and supplementary to those from e + e - colliders. This provides a rich, and highly rewarding program that is currently reaching full maturity. I report a few recent world-leading results on rare decays, CP-violation in B 0 s s mixing, b→s penguin decays, and charm physics.

  16. Numerical simulations of a proposed hollow electron beam collimator for the LHC upgrade at CERN.

    Energy Technology Data Exchange (ETDEWEB)

    Previtali, V. [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Stancari, G. [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Valishev, A. [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Redaelli, S. [European Organization for Nuclear Research (CERN), Geneva (Switzerland)

    2013-07-12

    In the last years the LHC collimation system has been performing over the expectations, providing the machine with a nearly perfect e cient cleaning system[1]. Nonetheless, when trying to push the existing accelerators to - and over - their design limits, all the accelerator components are required to boost their performances. In particular, in view of the high luminosity frontier for the LHC, the increased intensity would ask for a more e cient cleaning system. In this framework innovative collimation solutions are under evaluation[2]: one option is the usage of an hollow electron lens for beam halo cleaning. This work intends to study the applicability of an the hollow electron lens for the LHC collimation, by evaluating the case of the existing Tevatron e-lens applied to the nominal LHC 7 TeV beam. New e-lens operation modes are here proposed to standard enhance the electron lens halo removal e ect.

  17. Measurements of beam halo diffusion and population density in the Tevatron and in the Large Hadron Collider

    Energy Technology Data Exchange (ETDEWEB)

    Stancari, Giulio [Fermilab

    2015-03-01

    Halo dynamics influences global accelerator performance: beam lifetimes, emittance growth, dynamic aperture, and collimation efficiency. Halo monitoring and control are also critical for the operation of high-power machines. For instance, in the high-luminosity upgrade of the LHC, the energy stored in the beam tails may reach several megajoules. Fast losses can result in superconducting magnet quenches, magnet damage, or even collimator deformation. The need arises to measure the beam halo and to remove it at controllable rates. In the Tevatron and in the LHC, halo population densities and diffusivities were measured with collimator scans by observing the time evolution of losses following small inward or outward collimator steps, under different experimental conditions: with single beams and in collision, and, in the case of the Tevatron, with a hollow electron lens acting on a subset of bunches. After the LHC resumes operations, it is planned to compare measured diffusivities with the known strength of transverse damper excitations. New proposals for nondestructive halo population density measurements are also briefly discussed.

  18. [Corneal epithelial changes of soft contact lens wearers under a transmission electron microscope].

    Science.gov (United States)

    Gu, Hao; Tang, Li

    2015-03-01

    To investigate the difference in corneal epithelium between patients with and without soft contact lens (SCL) wearing, and to analyze corneal epithelial changes of the eyes with long-time SCL wearing. In this cross sectional study, the subjects were divided into two groups: 13 patients of daily SCL wearers and 11 control subjects who had never worn contact lenses. The flap of corneal epithelium was observed by transmission electron microscopy. The corneal epithelial microvillus density was compared between the two groups. Transmission electron micrographs of the control group showed a tight connection between cells, regularly aligned basal cells, and continuous basement membrane. Compared with the control group, SCL wearers showed incomplete basement membrane, swollen epithelial cells, swollen mitochondria, and widened intercellular interstices. The density of corneal epithelium microvilli [(0.071466 +/- 0.015889)/microm2 vs. (0.139851 +/- 0.024171)/micro2] was lower (t = 8.312, P < 0.05). Long-term SCL wearing can induce remarkable changes of corneal epithelial tissue, and the density of corneal epithelial microvilli decreases.

  19. Parton distribution and Tevatron jet data

    International Nuclear Information System (INIS)

    Alekhin, S.; Bluemlein, J.; Moch, S.

    2011-05-01

    We study the impact of Tevatron jet data on a global fit of parton distribution functions and on the determination of the value of the strong coupling constant α s (M Z ). The consequences are illustrated for cross sections of Higgs boson production at Tevatron and the LHC. (orig.)

  20. Calibration for medium resolution off-axis electron holography using a flexible dual-lens imaging system in a JEOL ARM 200F microscope

    International Nuclear Information System (INIS)

    Cantu-Valle, Jesus; Ruiz-Zepeda, Francisco; Mendoza-Santoyo, Fernando; Jose-Yacaman, Miguel; Ponce, Arturo

    2014-01-01

    In this work the calibration of a medium resolution off-axis electron holography using a dual-lens imaging system in a JEOL ARM 200F is shown. The objective dual-lens configuration allows adjusting the field of view from 35 nm to 2.5 μm. Subsequently, the parameters used in phase shift reconstruction were calibrated considering biprism voltage versus fringe spacing (σ) and versus fringe width (W). The reliability of the transmission electron microscope performance using these parameters was achieved using gold nanoparticles of known size and adjusting the excitation voltage of the lenses. - Highlights: • We presented the off-axis electron holography calibration in dual-lens mode of a JEOL ARM 200F. • We provide optimal conditions for a wide field of views varying the objective lens excitation. • The calibration was made using Au-nanoparticles controlling fringe width, spacing and contrast. • Application of electron holography to nanoparticles is also shown

  1. Fast Focal Point Correction in Prism-Coupled Total Internal Reflection Scanning Imager Using an Electronically Tunable Lens.

    Science.gov (United States)

    Zhu, Chenggang; Ge, Bilin; Chen, Ru; Zhu, Xiangdong; Mi, Lan; Ma, Jiong; Wang, Xu; Zheng, Fengyun; Fei, Yiyan

    2018-02-09

    Total internal reflection (TIR) is useful for interrogating physical and chemical processes that occur at the interface between two transparent media. Yet prism-coupled TIR imaging microscopes suffer from limited sensing areas due to the fact that the interface (the object plane) is not perpendicular to the optical axis of the microscope. In this paper, we show that an electrically tunable lens can be used to rapidly and reproducibly correct the focal length of an oblique-incidence scanning microscope (OI-RD) in a prism-coupled TIR geometry. We demonstrate the performance of such a correction by acquiring an image of a protein microarray over a scan area of 4 cm² with an effective resolution of less than 20 microns. The electronic focal length tuning eliminates the mechanical movement of the illumination lens in the scanning microscope and in turn the noise and background drift associated with the motion.

  2. Fast Focal Point Correction in Prism-Coupled Total Internal Reflection Scanning Imager Using an Electronically Tunable Lens

    Directory of Open Access Journals (Sweden)

    Chenggang Zhu

    2018-02-01

    Full Text Available Total internal reflection (TIR is useful for interrogating physical and chemical processes that occur at the interface between two transparent media. Yet prism-coupled TIR imaging microscopes suffer from limited sensing areas due to the fact that the interface (the object plane is not perpendicular to the optical axis of the microscope. In this paper, we show that an electrically tunable lens can be used to rapidly and reproducibly correct the focal length of an oblique-incidence scanning microscope (OI-RD in a prism-coupled TIR geometry. We demonstrate the performance of such a correction by acquiring an image of a protein microarray over a scan area of 4 cm2 with an effective resolution of less than 20 microns. The electronic focal length tuning eliminates the mechanical movement of the illumination lens in the scanning microscope and in turn the noise and background drift associated with the motion.

  3. Fermilab Tevatron and Pbar source status report

    International Nuclear Information System (INIS)

    Edwards, H.

    1986-08-01

    The antiproton production cycle is enumerated, and the commissioning of the antiproton source is described, giving milestones and major obstacles. The Tevatron collider operation is described, including procedure to load the Tevatron with three bunches of protons and three bunches of antiprotons. Commissioning of the Main Ring and Tevatron for collider operation is described. Development and accelerator studies in four areas were necessary: main ring RF manipulations; controls and applications software support; Tevatron storage and low-beta squeeze sequence; and study of various beam transfers, storage steps, and sequences. Final tests are described. A long range upgrade program is presently under evaluation to accomplish these goals: luminosity increase to 5 x 10 31 cm -2 sec -1 , production rates up to 4 x 10 11 antiprotons/hr, and intensity increase for fixed target operation. Beam quality is to be improved by the injector and main ring upgrades, and the luminosity goal is addressed by the Collider upgrade

  4. Heavy Flavour results from Tevatron

    Energy Technology Data Exchange (ETDEWEB)

    Borissov, G.; /Lancaster U.

    2012-06-01

    The CDF and D0 experiments finalize the analysis of their full statistics collected in the p{bar p} collisions at a center-of-mass energy of {radical}s = 1.96 TeV at the Fermilab Tevatron collider. This paper presents several new results on the properties of hadrons containing heavy b- and c-quarks obtained by both collaborations. These results include the search for the rare decays B{sup 0}, B{sub s}{sup 0} {yields} {mu}{sup +}{mu}{sup -} (CDF), the study of CP asymmetry in B{sub s} {yields} J{psi}{phi} decay (CDF, D0), the measurement of the like-sign dimuon charge asymmetry (D0), the measurement of CP asymmetry in D{sup 0} {yields} K{sup +}K{sup -} and D{sup 0} {yields} {pi}{sup +}{pi}{sup -} decays (CDF), and the new measurement of the B{sub s} {yields} D{sub s}{sup (*)+} D{sub s}{sup (*)-} branching fraction (CDF). Both experiments still expect to produce more results on the properties of heavy flavours.

  5. Applying EVM principles to Tevatron Beam Position Monitor Project

    International Nuclear Information System (INIS)

    Banerjee, Bakul

    2005-01-01

    At Fermi National Accelerator Laboratory (Fermilab), the Tevatron high energy particle collider must meet the increasing scientific demand of higher beam luminosity. To achieve this higher luminosity goal, U. S. Department of Energy (DOE) sponsored a major upgrade of capabilities of Fermilab's accelerator complex that spans five years and costs over fifty million dollars. Tevatron Beam Position Monitor (BPM) system upgrade is a part of this project, generally called RunII upgrade project. Since the purpose of the Tevatron collider is to detect the smashing of proton and anti-protons orbiting the circular accelerator in opposite directions, capability to detect positions of both protons and antiprotons at a high resolution level is a desirable functionality of the monitoring system. The original system was installed during early 1980s, along with the original construction of the Tevatron. However, electronic technology available in 1980s did not allow for the detection of significantly smaller resolution of antiprotons. The objective of the upgrade project is to replace the existing BPM system with a new system utilizing capabilities of modern electronics enhanced by a front-end software driven by a real-time operating software. The new BPM system is designed to detect both protons and antiprotons with increased resolution of up to an order of magnitude. The new system is capable of maintaining a very high-level of data integrity and system reliability. The system consists of 27 VME crates installed at 27 service buildings around the Tevatron ring servicing 236 beam position monitors placed underground, inside the accelerator tunnel. Each crate consists of a single Timing Generator Fanout module, custom made by Fermilab staff, one MVME processor card running VxWorks 5.5, multiple Echotek Digital Receiver boards complimented by custom made Filter Board. The VxWorks based front-end software communicates with the Main Accelerator Control software via a special

  6. Managing discovery risks--A Tevatron case study

    International Nuclear Information System (INIS)

    Bakul Banerjee

    2004-01-01

    To meet the increasing need for higher performance, Management of Fermi National Accelerator Laboratory has undertaken various projects to improve systems associated with the Tevatron high-energy particle collider located at Batavia, Illinois. One of the larger projects is the Tevatron Beam Position Monitor (BPM) system. The objective of this project is to replace the existing BPM electronics and software system that was originally installed during early 1980s, along with the original construction of the Tevatron.The original system consists of 236 beam position monitors located around the underground tunnel of the accelerator. Above ground control systems are attached to these monitors using pickup cables. When the Tevatron collider is operational, signals received from the BPMs are used to perform a number of control and diagnostic tasks. The original system can only capture the proton signals from the collider. The new system, when fully operational, will be able to capture combined proton and antiproton signals and will be able to separate the antiproton signal from the combined signal at high resolution. This significant enhancement was beyond the range of technical capabilities when the Tevatron was constructed about two decades ago. To take advantage of exceptional progress made in the hardware and software area in past two decades, Department of Energy approved funding of the BPM electronics and software replacement project. The approximate length of the project is sixteen months with a budget of four million dollars not including overhead, escalation, and contingencies. Apart from cost and schedule risks, there are two major risks associated with this research and development project. The primary risk is the risk of discovery. Since the Tevatron beam path is highly complex, BPMs have to acquire and process a large amount of data. In this environment, analysis of data to separate antiproton signals is even more complex. Finding an optimum algorithm that can

  7. Calibration for medium resolution off-axis electron holography using a flexible dual-lens imaging system in a JEOL ARM 200F microscope.

    Science.gov (United States)

    Cantu-Valle, Jesus; Ruiz-Zepeda, Francisco; Mendoza-Santoyo, Fernando; Jose-Yacaman, Miguel; Ponce, Arturo

    2014-12-01

    In this work the calibration of a medium resolution off-axis electron holography using a dual-lens imaging system in a JEOL ARM 200F is shown. The objective dual-lens configuration allows adjusting the field of view from 35nm to 2.5μm. Subsequently, the parameters used in phase shift reconstruction were calibrated considering biprism voltage versus fringe spacing (σ) and versus fringe width (W). The reliability of the transmission electron microscope performance using these parameters was achieved using gold nanoparticles of known size and adjusting the excitation voltage of the lenses. Copyright © 2014 Elsevier B.V. All rights reserved.

  8. Multiplicities and minijets at Tevatron Collider energies

    International Nuclear Information System (INIS)

    Sarcevic, I.

    1989-01-01

    We show that in the parton branching model, the probability distribution does not obey KNO scaling. As energy increases, gluon contribution to multiplicities increases, resulting in the widening of the probability distribution, in agreement with experimental data. We predict that the widening of the distribution will stop at Tevatron Collider energies due to the dominant role of gluons at these energies. We also find that the gluon contribution to the 'minijet' cross section increases with energy and becomes dominant at the Tevatron Collider. We calculate QCD minijet cross sections for a variety of structure functions, QCD scales and p T min . We compare our theoretical results with the experimental data and find that some of the structure functions and choices of scale are preferred by the experimental data. We give theoretical predictions for the minijet cross section at the Tevatron Collider, indicating the possibility of distinguishing between different sets of structure functions and choices of scale. (orig.)

  9. From the Tevatron to Project X

    CERN Multimedia

    Pier Oddone, Fermilab director (from CERN Courier)

    2011-01-01

    In the October issue of the CERN Courier, Fermilab Director Pier Oddone will present the past, present and future of the US laboratory after the Tevatron. The Bulletin presents some early extracts from his article…   Fermilab Director, Pier Oddone. The end of September marks the end of an era at Fermilab, with the shutdown of the Tevatron after 28 years of operation at the frontiers of particle physics. The Tevatron’s far-reaching legacy spans particle physics, accelerator science and industry. The collider established Fermilab as a world leader in particle physics research, a role that will be strengthened with a new set of facilities, programmes and projects in neutrino and rare-process physics, astroparticle physics, and accelerator and detector technologies. The Tevatron exceeded every expectation ever set for it. This remarkable machine achieved luminosities with antiprotons once considered impossible, reaching more than 4x1032 cm-2s-1 instantaneous luminosity and...

  10. Top quark mass measurement at the Tevatron

    Energy Technology Data Exchange (ETDEWEB)

    Guimaraes da Costa, Joao; /Harvard U.

    2004-12-01

    The authors report on the latest experimental measurements of the top quark mass by the CDF and D0 Collaborations at the Fermilab Tevatron. They present a new top mass measurement using the t{bar t} events collected by the D0 Collaboration in Run I between 1994 and 1996. This result is combined with previous measurements to yield a new world top mass average. They also describe several preliminary results using up to 193 pb{sup -1} of t{bar t} events produced in {bar p}p collisions at {radical}s = 1.96 TeV during the Run II of the Tevatron.

  11. Beam-beam effects in the Tevatron

    Energy Technology Data Exchange (ETDEWEB)

    Shiltsev, V.; Alexahin, Y.; Lebedev, V.; Lebrun, P.; Moore, R.S.; Sen, T.; Tollestrup, A.; Valishev, A.; Zhang, X.L.; /Fermilab

    2005-01-01

    The Tevatron in Collider Run II (2001-present) is operating with 6 times more bunches, many times higher beam intensities and luminosities than in Run I (1992-1995). Electromagnetic long-range and head-on interactions of high intensity proton and antiproton beams have been significant sources of beam loss and lifetime limitations. We present observations of the beam-beam phenomena in the Tevatron and results of relevant beam studies. We analyze the data and various methods employed in operations, predict the performance for planned luminosity upgrades, and discuss ways to improve it.

  12. Top and Electroweak Measurements at the Tevatron

    Energy Technology Data Exchange (ETDEWEB)

    Bartos, P. [Comenius U.

    2016-01-01

    In this report, we summarize the latest results of the top-quark mass and electroweak measurements from the Tevatron. Since the world combination of top-quark mass measurements was done, CDF and D0 experiments improved the precision of several results. Some of them reach the relative precition below 1% for a single measurement. From the electroweak results, we report on the WW and WZ production cross section, measurements of the weak mixing angle and indirect measurements of W boson mass. The Tevatron results of the weak mixing angle are still the most precise ones of hadron colliders.

  13. Measurement of the intensity of the beam in the abort gap at the Tevatron utilizing synchrotron light

    International Nuclear Information System (INIS)

    Thurman-Keup, R.; Lorman, E.; Meyer, T.; Pordes, S.; De Santis, S.

    2005-01-01

    This paper discusses the implementation of abort gap beam intensity monitoring at the Tevatron collider at Fermilab. There are two somewhat independent monitors which measure the intensity of the synchrotron light emitted by particles in the abort gaps. One system uses a gated Photomultiplier Tube (PMT) to measure the light intensity, and the other system uses a single lens telescope, gated image intensifier, and Charge Injection Device (CID) camera to image the beam

  14. B(s) properties at the Tevatron

    Energy Technology Data Exchange (ETDEWEB)

    Gomez-Ceballos, Guillelmo; /Cantabria U., Santander

    2005-11-01

    The Tevatron collider at Fermilab provides a very rich environment for the study B{sub s} mesons. In this paper they show a few selected topics from the CDF and D0 collaborations, giving special attention to the B{sub s} Mixing analyses. This note corresponds to the proceedings of the Hadron Collider Physics 2005 conference.

  15. Are PDFs still consistent with Tevatron data?

    Science.gov (United States)

    Sullivan, Zack

    2018-01-01

    As active data taking has moved to the LHC at CERN, more and more LHC data have been included into fits of parton distribution functions. An anomaly has arisen where formerly excellent agreement between theoretical predictions and experiment in single-top-quark production at the Tevatron is no longer quite as good. Is this indicative of a deeper issue?

  16. Are PDFs still consistent with Tevatron data?

    Directory of Open Access Journals (Sweden)

    Sullivan Zack

    2018-01-01

    Full Text Available As active data taking has moved to the LHC at CERN, more and more LHC data have been included into fits of parton distribution functions. An anomaly has arisen where formerly excellent agreement between theoretical predictions and experiment in single-top-quark production at the Tevatron is no longer quite as good. Is this indicative of a deeper issue?

  17. Photon final states at the Tevatron

    Energy Technology Data Exchange (ETDEWEB)

    Campanelli, Mario; /University Coll. London

    2008-04-01

    The authors present here several recent measurements involving associate production of photons and jets at the Tevatron. In particular, inclusive photon + met from D0, and photon + b-jets and photon + b-jet + leptons + MET from CDF are described in some detail. These measurements offer a good test of QCD predictions in rather complex final states.

  18. Fundamentally new physics at the Tevatron Collider?

    International Nuclear Information System (INIS)

    Chan Hongmo; Nellen, L.; Tsou Sheungtsun

    1989-02-01

    A new dispersion relation analysis of present pp-bar scattering data suggests the existence by Tevatron Collider energies of a threshold, of such nature, as is unlikely to be explainable in terms of known physics or any of its standard projections. (author)

  19. Tevatron targets three-year extension

    CERN Multimedia

    Harris, Margaret

    2010-01-01

    "Fermilab's Tevatron collider could get a new lease on life following a campaign to keep the facility running beyond the end of 2011, when the rival Large Hadron Collider (LHC) at Cern is scheduled to shut down for 15 months of repairs" (0.75 page)

  20. Parton distributions: HERA-Tevatron-LHC

    CERN Document Server

    Watt, Graeme

    2009-01-01

    The parton distribution functions (PDFs) are a non-negotiable input to almost all theory predictions at hadron colliders. In this talk, I introduce PDF determination by global analysis and discuss selected topics concerning recent relevant data from HERA and the Tevatron, before giving some prospects for the LHC. The combination of H1 and ZEUS cross sections reduces uncertainties and will be an important input to future global PDF analyses. The theoretical description of the heavy-quark contribution to structure functions at HERA has a significant influence on predictions at the LHC. New W and Z data from the Tevatron Run II provide important PDF constraints, but there are currently problems describing the latest data on the lepton charge asymmetry from W -> l nu decays. The Tevatron Run II jet production data prefer a smaller high-x gluon than the previous Run I data, which impacts on predictions for Higgs cross sections at the Tevatron. It is now possible to consistently calculate a combined "PDF+alpha_S" u...

  1. Field calculations, single-particle tracking, and beam dynamics with space charge in the electron lens for the Fermilab Integrable Optics Test Accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Noll, Daniel [Goethe Univ., Frankfurt (Germany); Stancari, Giulio [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)

    2015-11-17

    An electron lens is planned for the Fermilab Integrable Optics Test Accelerator as a nonlinear element for integrable dynamics, as an electron cooler, and as an electron trap to study space-charge compensation in rings. We present the main design principles and constraints for nonlinear integrable optics. A magnetic configuration of the solenoids and of the toroidal section is laid out. Singleparticle tracking is used to optimize the electron path. Electron beam dynamics at high intensity is calculated with a particle-in-cell code to estimate current limits, profile distortions, and the effects on the circulating beam. In the conclusions, we summarize the main findings and list directions for further work.

  2. Design and performance of a 30 KV electron gun with ten independent cathodes & a magnetic lens.

    Energy Technology Data Exchange (ETDEWEB)

    Rudys, Joseph Matthew; Reed, Kim Warren

    2006-08-01

    Measurements on a 30 kV electron gun with ten independent cathodes, operating in a 6.5 Tesla (T) magnetic field are presented. An earlier paper covered the design of this electron gun [1]. Experimental results are compared to model predictions. Beam current is compared to theoretical space charge limited flow.

  3. bubble chamber lens

    CERN Multimedia

    Before the days of electronic detectors, visual techniques were used to detect particles, using detectors such as spark chambers and bubble chambers. This plexiglass lens was used to focus the image of tracks so they could be photographed.

  4. Spatial Control of Photoemitted Electron Beams using a Micro-Lens-Array Transverse-Shaping Technique

    Energy Technology Data Exchange (ETDEWEB)

    Halavanau, A. [Northern Illinois U.; Qiang, G. [Tsinghua U., Beijing, Dept. Eng. Phys.; Ha, G. [POSTECH; Wisniewski, E. [Argonne (main); Piot, P. [NIU, DeKalb; Power, J. G. [Argonne (main); Gai, W. [Argonne (main)

    2017-07-24

    A common issue encountered in photoemission electron sources used in electron accelerators is the transverse inhomogeneity of the laser distribution resulting from the laser-amplification process and often use of frequency up conversion in nonlinear crystals. A inhomogeneous laser distribution on the photocathode produces charged beams with lower beam quality. In this paper, we explore the possible use of microlens arrays (fly-eye light condensers) to dramatically improve the transverse uniformity of the drive laser pulse on UV photocathodes. We also demonstrate the use of such microlens arrays to generate transversely-modulated electron beams and present a possible application to diagnose the properties of a magnetized beam.

  5. Off-axis electron holography with a dual-lens imaging system and its usefulness in 2-D potential mapping of semiconductor devices.

    Science.gov (United States)

    Wang, Y Y; Kawasaki, M; Bruley, J; Gribelyuk, M; Domenicucci, A; Gaudiello, J

    2004-11-01

    A variable magnification electron holography, applicable for two-dimensional (2-D) potential mapping of semiconductor devices, employing a dual-lens imaging system is described. Imaging operation consists of a virtual image formed by the objective lens (OL) and a real image formed in a fixed imaging plane by the objective minilens. Wide variations in field of view (100-900 nm) and fringe spacing (0.7-6 nm) were obtained using a fixed biprism voltage by varying the total magnification of the dual OL system. The dual-lens system allows fringe width and spacing relative to the object to be varied roughly independently from the fringe contrast, resulting in enhanced resolution and sensitivity. The achievable fringe width and spacing cover the targets needed for devices in the semiconductor technology road map from the 350 to 45 nm node. Two-D potential maps for CMOS devices with 220 and 70 nm gate lengths were obtained.

  6. Scanning Electron Microscopy of Nonconductive Specimens at Critical Energies in a Cathode Lens System

    Czech Academy of Sciences Publication Activity Database

    Frank, Luděk; Zadražil, Martin; Müllerová, Ilona

    2001-01-01

    Roč. 23, č. 1 (2001), s. 36-50 ISSN 0161-0457 R&D Projects: GA ČR GA202/96/0961; GA ČR GA202/99/0008 Institutional research plan: CEZ:AV0Z2065902 Keywords : scanning electron microscopy * specimen charging * nonconductive specimens Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 0.389, year: 2001

  7. The Tevatron Hadron Collider: A short history

    International Nuclear Information System (INIS)

    Tollestrup, A.V.

    1994-11-01

    The subject of this presentation was intended to cover the history of hadron colliders. However this broad topic is probably better left to historians. I will cover a much smaller portion of this subject and specialize my subject to the history of the Tevatron. As we will see, the Tevatron project is tightly entwined with the progress in collider technology. It occupies a unique place among accelerators in that it was the first to make use of superconducting magnets and indeed the basic design now forms a template for all machines using this technology. It was spawned in an incredibly productive era when new ideas were being generated almost monthly and it has matured into our highest energy collider complete with two large detectors that provide the major facility in the US for probing high Pt physics for the coming decade

  8. The Physics Case for Extended Tevatron Running

    Energy Technology Data Exchange (ETDEWEB)

    Wood, Darien R.

    2010-11-01

    Run II of the Tevatron collider at Fermilab is currently scheduled to end late in 2011. Given the current performance of the collider and of the CDF and D0 detectors, it is estimated that the current data set could be approximately doubled with a run extended into 2014. A few examples are presented of the physics potential of these additional statistics. These are discussed in the context of the expected reach of the LHC 7 TeV data and the existing Tevatron data. In particular, an extraordinary opportunity is described which could probe the existence of a standard model Higgs boson with mass in the currently preferred region between 115 GeV and 150 GeV.

  9. Measuring the orbit length of the Tevatron

    International Nuclear Information System (INIS)

    Kerns, C.; Kerns, Q.; Miller, H.

    1985-06-01

    The orbit length in the Tevatron was measured when coasting beam was first obtained. The method was time-of-flight, using a vernier phase comparison between beam pickup signals and a synthesizer sine wave. Some effort was spent making a stable phase detector so that it would not be a limiting factor. The results exhibited a repeatability of a few Hz at 53 MHz, corresponding to a mean radius measurement to 0.1 mm. 5 refs., 4 figs

  10. Longitudinal damping in the Tevatron collider

    Energy Technology Data Exchange (ETDEWEB)

    Kerns, Q.A.; Jackson, G.; Kerns, C.R.; Miller, H.; Reid, J.; Siemann, R.; Wildman, D.

    1989-03-01

    This paper describes the damper design for 6 proton on 6 pbar bunches in the Tevatron collider. Signal pickup, transient phase detection, derivative networks, and phase correction via the high-level rf are covered. Each rf station is controlled by a slow feedback loop. In addition, global feedback loops control each set of four cavities, one set for protons and one set for antiprotons. Operational experience with these systems is discussed. 7 refs., 9 figs.

  11. Recent QCD Studies at the Tevatron

    Energy Technology Data Exchange (ETDEWEB)

    Group, Robert Craig

    2008-04-01

    Since the beginning of Run II at the Fermilab Tevatron the QCD physics groups of the CDF and D0 experiments have worked to reach unprecedented levels of precision for many QCD observables. Thanks to the large dataset--over 3 fb{sup -1} of integrated luminosity recorded by each experiment--important new measurements have recently been made public and will be summarized in this paper.

  12. Longitudinal damping in the Tevatron collider

    International Nuclear Information System (INIS)

    Kerns, Q.A.; Jackson, G.; Kerns, C.R.; Miller, H.; Reid, J.; Siemann, R.; Wildman, D.

    1989-03-01

    This paper describes the damper design for 6 proton on 6 pbar bunches in the Tevatron collider. Signal pickup, transient phase detection, derivative networks, and phase correction via the high-level rf are covered. Each rf station is controlled by a slow feedback loop. In addition, global feedback loops control each set of four cavities, one set for protons and one set for antiprotons. Operational experience with these systems is discussed. 7 refs., 9 figs

  13. Fermilab tevatron five refrigerator system tests

    International Nuclear Information System (INIS)

    Rode, C.; Ferry, R.; Leiniger, M.; Makara, J.; Misek, J.; Mizicko, D.; Richied, D.; Theilacker, J.

    1982-01-01

    The Fermilab Tevatron refrigeration system is described with the layout illustrated. The compressor control loops, the refrigerator control loops, and magnet control loops (two per refrigerator) are described and each illustrated. The mobile purifier is described. A five refrigerator test is presented, using two compressor buildings, satellite refrigerator concept test and the test current to the writing. The configuration of the five refrigerator test is diagramed

  14. Higgs boson studies at the Tevatron

    Czech Academy of Sciences Publication Activity Database

    Aaltonen, L.; Abbott, B.; Abazov, V. M.; Kupčo, Alexander; Lokajíček, Miloš; Lysák, Roman

    2013-01-01

    Roč. 88, č. 5 (2013), "052014-1"-"052014-29" ISSN 1550-7998 R&D Projects: GA MŠk(CZ) LG12006 Institutional support: RVO:68378271 Keywords : Higgs particle * mass * vector boson * gluon * fusion * Batavia TEVATRON Coll * CDF * DZERO * anti-p p * interaction Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 4.864, year: 2013

  15. Three-dimensional apoptotic nuclear behavior analyzed by means of Field Emission in Lens Scanning Electron Microscope

    Directory of Open Access Journals (Sweden)

    S. Salucci

    2015-09-01

    Full Text Available Apoptosis is an essential biological function required during embryogenesis, tissue homeostasis, organ development and immune system regulation. It is an active cell death pathway involved in a variety of pathological conditions. During this process cytoskeletal proteins appear damaged and undergo an enzymatic disassembling, leading to formation of apoptotic features. This study was designed to examine the three-dimensional chromatin behavior and cytoskeleton involvement, in particular actin re-modeling. HL-60 cells, exposed to hyperthermia, a known apoptotic trigger, were examined by means of a Field Emission in Lens Scanning Electron Microscope (FEISEM. Ultrastructural observations revealed in treated cells the presence of apoptotic patterns after hyperthermia trigger. In particular, three-dimensional apoptotic chromatin rearrangements appeared involving the translocation of filamentous actin from cytoplasm to the nucleus. FEISEM immunogold techniques showed actin labeling and its precise three-dimensional localization in the diffuse chromatin, well separated from the condensed one. The actin presence in dispersed chromatin inside the apoptotic nucleus can be considered an important feature, indispensable to permit the apoptotic machinery evolution.

  16. Summary of the LARP Mini-Workshop on Electron Lens Simulations at BNL

    Energy Technology Data Exchange (ETDEWEB)

    Valishev,A.; Luo,Y.; Fischer, W.

    2009-03-01

    This was a 1 day workshop that brought together a group of people working on beam-beam simulations, in particular those comprising the simulation part of LARP Beam-Beam Task. There were 8 participants from BNL, and 3 from FNAL. The goals of the mini-workshop were: (1) To identify the beam-beam effects in LHC and RHIC that could be mitigated using electron lenses, and to define machine and beam parameters one should be looking at in simulations; (2) To assess the group capabilities and establish means of collaboration; and (3) To establish near and long term simulation program, set priorities and a schedule.

  17. Increasing the energy of the Fermilab Tevatron accelerator

    International Nuclear Information System (INIS)

    Fuerst, J.D.; Theilacker, J.C.

    1994-07-01

    The superconducting Tevatron accelerator at Fermilab has reached its eleventh year of operation since being commissioned in 1983. Last summer, four significant upgrades to the cryogenic system became operational which allow Tevatron operation at higher energy. This came after many years of R ampersand D, power testing in sectors (one sixth) of the Tevatron, and final system installation. The improvements include the addition of cold helium vapor compressors, supporting hardware for subatmospheric operation, a new satellite refrigerator control system, and a higher capacity central helium liquefier. A description of each cryogenic upgrade, commissioning experience, and attempts to increase the energy of the Tevatron are presented

  18. Engineers’ Responsibilities for Global Electronic Waste: Exploring Engineering Student Writing Through a Care Ethics Lens

    Science.gov (United States)

    Campbell, Ryan C.; Wilson, Denise

    2016-01-01

    This paper provides an empirically informed perspective on the notion of responsibility using an ethical framework that has received little attention in the engineering-related literature to date: ethics of care. In this work, we ground conceptual explorations of engineering responsibility in empirical findings from engineering student’s writing on the human health and environmental impacts of “backyard” electronic waste recycling/disposal. Our findings, from a purposefully diverse sample of engineering students in an introductory electrical engineering course, indicate that most of these engineers of tomorrow associated engineers with responsibility for the electronic waste (e-waste) problem in some way. However, a number of responses suggested attempts to deflect responsibility away from engineers towards, for example, the government or the companies for whom engineers work. Still other students associated both engineers and non-engineers with responsibility, demonstrating the distributed/collective nature of responsibility that will be required to achieve a solution to the global problem of excessive e-waste. Building upon one element of a framework for care ethics adopted from the wider literature, these empirical findings are used to facilitate a preliminary, conceptual exploration of care-ethical responsibility within the context of engineering and e-waste recycling/disposal. The objective of this exploration is to provide a first step toward understanding how care-ethical responsibility applies to engineering. We also hope to seed dialogue within the engineering community about its ethical responsibilities on the issue. We conclude the paper with a discussion of its implications for engineering education and engineering ethics that suggests changes for educational policy and the practice of engineering. PMID:27368195

  19. Engineers' Responsibilities for Global Electronic Waste: Exploring Engineering Student Writing Through a Care Ethics Lens.

    Science.gov (United States)

    Campbell, Ryan C; Wilson, Denise

    2017-04-01

    This paper provides an empirically informed perspective on the notion of responsibility using an ethical framework that has received little attention in the engineering-related literature to date: ethics of care. In this work, we ground conceptual explorations of engineering responsibility in empirical findings from engineering student's writing on the human health and environmental impacts of "backyard" electronic waste recycling/disposal. Our findings, from a purposefully diverse sample of engineering students in an introductory electrical engineering course, indicate that most of these engineers of tomorrow associated engineers with responsibility for the electronic waste (e-waste) problem in some way. However, a number of responses suggested attempts to deflect responsibility away from engineers towards, for example, the government or the companies for whom engineers work. Still other students associated both engineers and non-engineers with responsibility, demonstrating the distributed/collective nature of responsibility that will be required to achieve a solution to the global problem of excessive e-waste. Building upon one element of a framework for care ethics adopted from the wider literature, these empirical findings are used to facilitate a preliminary, conceptual exploration of care-ethical responsibility within the context of engineering and e-waste recycling/disposal. The objective of this exploration is to provide a first step toward understanding how care-ethical responsibility applies to engineering. We also hope to seed dialogue within the engineering community about its ethical responsibilities on the issue. We conclude the paper with a discussion of its implications for engineering education and engineering ethics that suggests changes for educational policy and the practice of engineering.

  20. Electron lenses for super-colliders

    CERN Document Server

    Shiltsev, Vladimir D

    2016-01-01

    This book provides a comprehensive overview of the operating principles and technology of electron lenses in supercolliders.  Electron lenses are a novel instrument for high energy particle accelerators, particularly for the energy-frontier superconducting hadron colliders, including the Tevatron, RHIC, LHC and future very large hadron colliders.  After reviewing the issues surrounding beam dynamics in supercolliders, the book offers an introduction to the electron lens method and its application.  Further chapters describe the technology behind the electron lenses which have recently been proposed, built and employed for compensation of beam-beam effects and for collimation of high-energy high-intensity beams, for compensation of space-charge effects and several other applications in accelerators. The book will be an invaluable resource for those involved in the design, construction and operation of the next generation of hadron colliders.

  1. Present state of Tevatron lower temperature operation

    International Nuclear Information System (INIS)

    Norris, B.L.

    1996-09-01

    Fermilab continues to work on raising the particle energy of the Tevatron by lowering magnet temperatures using cold vapor compressors. In 1995, another two rounds of power tests were completed. These power tests, although showing significant improvement over the initial tests of 1993-94, have led to the conclusion that 1000 GeV operation cannot be attained without replacing/rearranging magnets with lower quench currents before the next Collider Run in 1999. Development of more cold compressor control strategies also continues

  2. Recent Tevatron Results on CP-Violation

    Energy Technology Data Exchange (ETDEWEB)

    Garbincius, Peter H. [Fermilab

    2014-08-25

    Using their full Tevatron Run II data sets, the CDF and D0 Experiments present measurements of CP-violating asymmetries in the charmless decay of bottom baryons Lambda-b => p pi-, Lambda-b => p K-, and also for Bs0 => K- pi+, B0 => K+ pi-, Ds => phi pi, and for single muons and like-sign dimuons in p-pbar collisions. Except for the like-sign dimuon asymmetry, these asymmetry measurements are consistent with available predictions of the standard model.

  3. Emittance growth due to Tevatron flying wires

    Energy Technology Data Exchange (ETDEWEB)

    Syphers, M; Eddy, Nathan

    2004-06-01

    During Tevatron injection, Flying Wires have been used to measure the transverse beam size after each transfer from the Main Injector in order to deduce the transverse emittances of the proton and antiproton beams. This amounts to 36 + 9 = 45 flies of each of 3 wire systems, with an individual wire passing through each beam bunch twice during a single ''fly''. below they estimate the emittance growth induced by the interaction of the wires with the particles during these measurements. Changes of emittance from Flying Wire measurements conducted during three recent stores are compared with the estimations.

  4. Tevatron Results on Heavy Flavor Production and Decay

    Energy Technology Data Exchange (ETDEWEB)

    Scuri, Fabrizio [INFN, Pisa

    2014-09-02

    The most recent results on heavy flavor production and decays from the Tevatron experiments CDF and D0 are summarized and compared with some LHC experiment results. The collected data sample refers to the full Tevatron Run II operation and it corresponds to about 10 inverse fb of integrated luminosity per experiment.

  5. Electroweak, top and bottom physics at the Tevatron

    Energy Technology Data Exchange (ETDEWEB)

    Ukegawa, Fumihiko; /Tsukuba U.

    2004-10-01

    The Tevatron Run-II program has been in progress since 2001, and the CDF and D0 experiments have been operational with upgraded detectors. Coupled with recent improvements in the Tevatron accelerator performance, the experiments have started producing important physics results and measurements. They report these measurements as well as prospects in the near future.

  6. Flavor gauge bosons at the Fermilab Tevatron

    International Nuclear Information System (INIS)

    Burdman, Gustavo; Chivukula, R. Sekhar; Evans, Nick

    2000-01-01

    We investigate collider signals for gauged flavor symmetries that have been proposed in models of dynamical electroweak symmetry breaking and fermion mass generation. We consider the limits on the masses of the gauge bosons in these models which can be extracted from Fermilab Tevatron run I data in dijet production. Estimates of the run II search potential are provided. We show that the models also give rise to significant signals in single top quark production which may be visible at run II. In particular we study chiral quark family symmetry and SU(9) chiral flavor symmetry. The run I limits on the gauge bosons in these models lie between 1.5 and 2 TeV and should increase to about 3 TeV in run II. Finally, we show that an SU(12) enlargement of the SU(9) model, including leptonic interactions, is constrained by low energy atomic parity violation experiments to lie outside the reach of the Tevatron. (c) 2000 The American Physical Society

  7. Sonic helium detectors in the Fermilab Tevatron

    Energy Technology Data Exchange (ETDEWEB)

    Bossert, R.J.; /Fermilab

    2006-01-01

    In the Fermilab Tevatron cryogenic system there are many remotely located low-pressure plate relief valves that must vent large volumes of cold helium gas when magnet quenches occur. These valves can occasionally stick open or not reseat completely, resulting in a large helium loss. As such, the need exists for a detector to monitor the relief valve's discharge area for the presence of helium. Due to the quantity needed, cost is an important factor. A unit has been developed and built for this purpose that is quite inexpensive. Its operating principle is based on the speed of sound, where two closely matched tubes operate at their acoustic resonant frequency. When helium is introduced into one of these tubes, the resulting difference in acoustic time of flight is used to trigger an alarm. At present, there are 39 of these units installed and operating in the Tevatron. They have detected many minor and major helium leaks, and have also been found useful in detecting a rise in the helium background in the enclosed refrigerator buildings. This paper covers the construction, usage and operational experience gained with these units over the last several years.

  8. Energy deposition in TEVATRON magnets from beam losses in interaction regions

    International Nuclear Information System (INIS)

    Ginneken, A.V.

    1988-10-01

    In addition to interacting in the detector, particles produced at an interaction region also deposit energy, with less desirable consequences, in magnets and other components of the accelerator. This note briefly assesses the damage potential of these (essentially unavoidable) beam losses from the viewpoint of quenching of superconducting magnets in an upgraded Tevatron, specifically for the 1 TeV p-/ovrreverse arrowstring/p option with a luminosity of 10 31 cm/sup - 2/ sec -1 , through the results carry more generality. Related issues such as radiation damage to detector electronics or other components are not addressed here. These are thought to be less problematic at the Tevatron, as in thus far supported by operational experience. 8 refs., 10 figs

  9. Objective lens

    Science.gov (United States)

    Olczak, Eugene G. (Inventor)

    2011-01-01

    An objective lens and a method for using same. The objective lens has a first end, a second end, and a plurality of optical elements. The optical elements are positioned between the first end and the second end and are at least substantially symmetric about a plane centered between the first end and the second end.

  10. Diagnostics of the Fermilab Tevatron using an AC dipole

    Science.gov (United States)

    Miyamoto, Ryoichi

    The Fermilab Tevatron is currently the world's highest energy colliding beam facility. Its counter-rotating proton and antiproton beams collide at 2 TeV center-of-mass. Delivery of such intense beam fluxes to experiments has required improved knowledge of the Tevatron's beam optical lattice. An oscillating dipole magnet, referred to as an AC dipole, is one of such a tool to non-destructively assess the optical properties of the synchrotron. We discusses development of an AC dipole system for the Tevatron, a fast-oscillating (f˜20 kHz) dipole magnet which can be adiabatically turned on and off to establish sustained coherent oscillations of the beam particles without affecting the transverse emittance. By utilizing an existing magnet and a higher power audio amplifier, the cost of the Tevatron AC dipole system became relatively inexpensive. We discuss corrections which must be applied to the driven oscillation measurements to obtain the proper interpretation of beam optical parameters from AC dipole studies. After successful operations of the Tevatron AC dipole system, AC dipole systems, similar to that in the Tevatron, will be build for the CERN LHC. We present several measurements of linear optical parameters (beta function and phase advance) for the Tevatron, as well as studies of non-linear perturbations from sextupole and octupole elements.

  11. Recent heavy flavor results from the Tevatron

    Energy Technology Data Exchange (ETDEWEB)

    Dorigo, Mirco; /Trieste U. /INFN, Trieste

    2012-05-01

    The CDF and D0 experiments at the Tevatron p{bar p} collider have pioneered and established the role of flavor physics in hadron collisions. A broad program is now at its full maturity. We report on three new results sensitive to physics beyond the standard model, obtained using the whole CDF dataset: a measurement of the difference of CP asymmetries in K{sup +}K{sup -} and {pi}{sup +}{pi}{sup -} decays of D{sup 0} mesons, new bounds on the B{sub s}{sup 0} mixing phase and on the decay width difference of B{sub s}{sup 0} mass-eigenstates, and an update of the summer 2011 search for B{sub (s)}{sup 0} mesons decaying into pairs of muons. Finally, the D0 confirmation of the observation of a new hadron, the {chi}{sub b}(3P) state, is briefly mentioned.

  12. Operation of the tevatron extraction system

    International Nuclear Information System (INIS)

    Finley, D.A.; Harrison, M.; Merz, W.; Pfeffer, H.

    1985-01-01

    The Fermilab Tevatron is currently in the middle of its second running period for fixed target physics. Steady operation has been established at 800 GeV with l X 10 13 protons being extracted. Beam spill over the 20 - 23 second flattop is regulated by a closed loop feedback and a feed forward learning system controlled by a microprocessor. Eight power supplies have their waveforms programmed by the microprocessor in an attempt to reduce the modulation on the beam spill. In addition the microprocessor can insert a pause in the slow spill and cause the extraction of a high intensity (3 X 10 12 ) fast (1-2 milliseconds long) pulse. A description of the extraction system as well as analysis of the spill modulation encountered during commissioning are presented in this paper. Current status of the spill structure is also discussed

  13. Initial performance of upgraded Tevatron cryogenic systems

    International Nuclear Information System (INIS)

    Norris, B.L.

    1996-09-01

    Fermilab began operating a re-designed satellite refrigerator systems in November 1993. Upgrades were installed to operate the Tevatron at a magnet temperature of 3.5 K, approximately 1K lower than the original design. Refrigerator upgrades included new valve boxes, larger reciprocating expanders, the installation of cold vapor compressors, new sub-atmospheric instrumentation and an entirely new distributed controls system. Cryogenic system reliability data for Colliding Physics Run 1B is presented emphasizing a failure analysis for each aspect of the upgrade. Comparison to data for Colliding Physics Run 1A (previous to upgrade) is presented to show the impact of a major system overhaul. New operational problems and their solutions are presented in detail

  14. Neutrino results from the Fermilab Tevatron

    International Nuclear Information System (INIS)

    Shaevitz, M.H.; Arroyo, C.; Bachmann, K.T.; Bazarko, A.O.; Blair, R.E.; Bolton, T.A.; Foudas, C.; King, B.J.; Lefmann, W.C.; Leung, W.C.; Mishra, S.R.; Oltman, E.; Quintas, P.Z.; Rabinowitz, S.A.; Sciulli, F.; Seligman, W.G.; Merritt, F.S.; Oreglia, M.J.; Schumm, B.A.; Bernstein, R.H.; Borcherding, F.; Fisk, H.E.; Lamm, M.J.; Marsh, W.; Merritt, K.W.B.; Schellman, H.; Yovanovitch, D.D.; Bodek, A.; Budd, H.S.; De Barbaro, P.; Salcumoto, W.K.; Kinnel, T.S.; Sandler, P.H.; Smith, W.H.

    1995-01-01

    Results from the high-energy, high-statistics studies of neutrino nucleon interactions by the CCFR collaboration at the Fermilab Tevatron are described. Using a data sample of over 3.7million events with energies up to 600GeV, precision measurements are presented for the weak mixing angle, sin 2 θ w , the structure functions, F 2 (x,Q 2 ) and xF 3 (x,Q 2 ), aud the strange quark distribution, xs(x,Q 2 ). Comparisons of these measurements to those obtained in other processes are made in the context of global electroweak and QCD tests. Prospects for the next generation measurements by the NuTeV collaboration at Fermilab are also presented. ((orig.))

  15. Scientific Opportunity: the Tevatron and the LHC

    CERN Multimedia

    2010-01-01

    The press makes much of the competition between CERN’s LHC and Fermilab’s Tevatron in the search for the Higgs boson. This competitive aspect is real, and probably adds spice to the scientific exploration, but for us such reporting often feels like spilling the entire pepper shaker over a fine meal. The media’s emphasis on competition obscures the more important substance of our long-standing collaboration in scientific discovery.   Our laboratories and our communities have worked together for decades. Europeans have contributed greatly to the Tevatron’s many successes, including the discovery of the top quark, the discovery of fast oscillations in the decay of strange B mesons and the many searches for new phenomena. Americans have contributed to many programs at CERN, notably the extraordinary precision measurements of LEP, and more recently construction of the LHC accelerator and detectors. Fermilab scientists played a vital role throughout 2009 in...

  16. bubble chamber lens

    CERN Multimedia

    Was used in a PS experiment. Before the days of electronic detectors, visual techniques were used to detect particles, using detectors such as spark chambers and bubble chambers. This plexiglass lens was used to focus the image of tracks so they could be photographed.

  17. Tevatron The Cinderella story or the art of collider

    CERN Document Server

    CERN. Geneva

    2007-01-01

    The Tevatron Collider at Fermilab (Batavia, IL, USA) is the world's highest energy particle collider at 1.8TeV c.m.e. The machine was a centerpiece of the US and world's High Energy Physics for many years. Currently, the Tevatron is in the last years of its operation in so-called Run II which started 2001 and is tentatively scheduled to end in 2010. In this lecture series, we'll try to learn from the exciting story of the Tevatron Collider Run II: the story of long preparations, great expectations, initial difficulties, years of "blood and sweat", continuous upgrades, exceeding its goals, high emotions, tune-up of accelerator organization for "combat fighting". The lectures will cover Introduction to the Tevatron, its history and Run II; "Plumbing" Issues; Beam Physics Issues; Luminosity Progress; Organization of Troops and Lessons for LHC.

  18. Entwicklungsarbeit am Spurendetektor fur das CDF Experiment am Tevatron

    Energy Technology Data Exchange (ETDEWEB)

    Hartmann, Frank [Univ. of Karlsruhe (TH) (Germany)

    2000-02-01

    Silicon, the element, which revolutionized the development of electronics, is known as an important and multiusable material, dominating todays electronic technology. It's properties are well investigated and today well known. Silicon is used in solar cells, computers and telecommunications. Since the Sixties semiconductors have been used as particle detectors. Initially they were operated in fixed- target experiments as calorimeters and as detectors with a high precision track reconstruction. Since the Eighties they are widely used in collider experiments as silicon microstrip or silicon pixel detectors near the primary vertex. Silicon sensors have a very good intrinsic energy resolution: for every 3.6 eV released by a particle crossing the medium, one electron-hole pair is produced. Compared to 30 eV required to ionize a gas molecule in a gaseous detector, one gets 10 times the number of particles. The average energy loss and high ionized particle number with 390 e V / μm ~ 108 (electron - hole pairs)/ μm is effectively high due to the high density of silicon. These detectors allow a high precision reconstruction of tracks, primary and secondary vertices, which are especially important for b flavour tagging. The Tevatron and its detectors are being upgraded for the next data taking run starting in 2001 (RUN II). The Collider Detector at Fermilab (CDF) [2] for the upcoming Run II and its upgraded components are described in chapter 2. The main upgrade project is the design and construction of a completely new inner tracking system.

  19. W mass and Triple Gauge Couplings at Tevatron

    Directory of Open Access Journals (Sweden)

    Pétroff Pierre

    2013-05-01

    Full Text Available The W mass is a crucial parameter in the Standard Model (SM of particle physics, providing constraints on the mass of the Higgs boson as well as on new physics models via quantum loop corrections. On the other hand, any deviation of the triple gauge boson couplings (TGC from their values predicted by the SM would be also an indication for new physics. We present recent measurements on W boson mass and searches for anomalous TGC (aTGC in Wγ, Zγ, WW, WZ and ZZ at Fermilab Tevatron both by CDF and DØ Collaborations. The CDF Collaboration has measured the W boson mass using data corresponding to 2.2 fb−1 of integrated luminosity. The measurement, performed using electron and muon decays of W boson, yields a mass of MW = 80387 ± 19 MeV. The DØ Collaboration has measured MW = 80367 ± 26 MeV with data corresponding to 4.3 fb−1 of integrated luminosity in the channel W → ev. The combination with an earlier DØ result, using independant data sample at 1 fb−1 of integrated luminosity, yields MW = 80375 ± 23 MeV. The limits on anomalous TGCs parameters are consistent with the SM expectations.

  20. Updated overview of the Tevatron control system

    International Nuclear Information System (INIS)

    Lucas, P.

    1987-10-01

    A single unified control system is used for all of the Fermilab accelerators and storage rings, from the LINAC to the Tevatron and antiproton source. A review of the general features is given - these include a 'host' system consisting of a number of minicomputers integrated with many distributed microprocessors in a variety of subsystems, usage of an in-house developed protocol, GAS, for communication between the two classes of machines, and a Parameter Page program, designed in conjunction with the system database, which allows a wide variety of quantities to be read and set in a coherent fashion. Recent developments include the implementation of a block transfer and 'fast time plot' facility through CAMAC, inclusion of several new computers in the host, a better understanding of system throughput, greatly improved reliability, advent of programs which sequence a large number of independent operations, and the construction of new hardware subsystems. Possible future system upgrades will be briefly presented. A summary of the utilization of a quite large software staff, at a time when the system is no longer under construction, will be discussed

  1. New analytical calculations of the resonance modes in lens-shaped cavities: applications to the calculations of the energy levels and electronic wavefunctions in quantum dots

    International Nuclear Information System (INIS)

    Even, J; Loualiche, S

    2003-01-01

    The problem of the energy levels and electronic wavefunctions in quantum dots is studied in the parabolic coordinates system. A conventional effective mass Hamiltonian is written. For an infinite potential barrier, it is related to the more general problem of finding the resonance modes in a cavity. The problem is found to be separable for a biconvex-shaped cavity or quantum dot with an infinite potential barrier. This first shape of quantum dot corresponds to the intersection of two orthogonal confocal parabolas. Then plano-convex lens-shaped cavities or quantum dots are studied. This problem is no more separable in the parabolic coordinates but using symmetry properties, we show that the exact solutions of the problem are simple combinations of the previous solutions. The same approach is used for spherical coordinates and hemispherical quantum dots. It is finally shown that convex lens-shaped quantum dots give a good description of self-organized InAs quantum dots grown on InP

  2. Quadrupole magnetic lens

    International Nuclear Information System (INIS)

    Piskunov, V.A.

    1981-01-01

    The following connection of windings of electromagnet is suggested for simplification of the design of qUadrupole magnetic lens intended for use in radiotechnical and electron-optical devices. The mentioned windings are connected with each other by a bridge scheme and the variable resistors are switched in its diagonals in the lens containing four electromagnet with windings connected with two variable resistors the mobile contacts of which are connected with a direct current source. Current redistribution between left windings and right windings takes place at shift of mobile contact of variable resistor, and current redistribution between upper and low coils of electromagnets takes place at shifting mobile contact of the other variable resistor. In this case smooth and independent electron-optical misalignment of lens by two mutually perpendicular directions proceeds. Use of the given design of the lens in the oscillograph permits to use printing assembly for alignment plate and to reduce the number of connections at the expense of decreasing the number of resistors

  3. Simultaneous Scanning Electron Microscope Imaging of Topographical and Chemical Contrast Using In-Lens, In-Column, and Everhart-Thornley Detector Systems.

    Science.gov (United States)

    Zhang, Xinming; Cen, Xi; Ravichandran, Rijuta; Hughes, Lauren A; van Benthem, Klaus

    2016-06-01

    The scanning electron microscope provides a platform for subnanometer resolution characterization of material morphology with excellent topographic and chemical contrast dependent on the used detectors. For imaging applications, the predominantly utilized signals are secondary electrons (SEs) and backscattered electrons (BSEs) that are emitted from the sample surface. Recent advances in detector technology beyond the traditional Everhart-Thornley geometry have enabled the simultaneous acquisition and discrimination of SE and BSE signals. This study demonstrates the imaging capabilities of a recently introduced new detector system that consists of the combination of two in-lens (I-L) detectors and one in-column (I-C) detector. Coupled with biasing the sample stage to reduce electron-specimen interaction volumes, this trinity of detector geometry allows simultaneous acquisition of signals to distinguish chemical contrast from topographical changes of the sample, including the identification of surface contamination. The I-C detector provides 4× improved topography, whereas the I-L detector closest to the sample offers excellent simultaneous chemical contrast imaging while not limiting the minimization of working distance to obtain optimal lateral resolution. Imaging capabilities and contrast mechanisms for all three detectors are discussed quantitatively in direct comparison to each other and the conventional Everhart-Thornley detector.

  4. Coherent betatron instability in the Tevatron

    International Nuclear Information System (INIS)

    Bogacz, S.A.; Harrison, M.; Ng, K.Y.

    1988-01-01

    The coherent betatron instability was first observed during the recent 1987-88 Tevatron fixed target run. In this operating mode 1000 consecutive bunches are loaded into the machine at 150 GeV with a bunch spacing of 18.8 /times/ 10 -9 sec (53 MHz). The normalized transverse emittance is typically 15 π /times/ 10 -6 m rad in each plane with a longitudinal emittance of about 1.5 eV-sec. The beam is accelerated to 800 GeV in 13 sec. and then it is resonantly extracted during a 23 sec flat top. As the run progressed the bunch intensities were increased until at about 1.4 /times/ 10 10 ppb (protons per bunch) we experienced the onset of a coherent horizontal oscillation taking place in the later stages of the acceleration cycle (>600 GeV). This rapidly developing coherent instability results in a significant emittance growth, which limits machine performance and in a catastrophic scenario it even prevents extraction of the beam. In this paper we will present a simple analytic description of the observed instability. We will show that a combination of a resistive wall coupled bunch effect and a single bunch slow head-tail instability is consistent with the above observations. Finally, a systematic numerical analysis of our model (growth-time vs chromaticity plots) points to the existence of the ≥1 slow head-tail modes as a plausible mechanism for the observed coherent instability. This last claim, as mentioned before, does not have conclusive experimental evidence, although it is based on a very good agreement between the measured values of the instability growth-time and the ones calculated on the basis of our model. 4 refs., 3 figs

  5. Lens Model

    DEFF Research Database (Denmark)

    Nash, Ulrik William

    2014-01-01

    Firms consist of people who make decisions to achieve goals. How do these people develop the expectations which underpin the choices they make? The lens model provides one answer to this question. It was developed by cognitive psychologist Egon Brunswik (1952) to illustrate his theory...

  6. Properties of the cathode lens combined with a focusing magnetic/immersion-magnetic lens

    International Nuclear Information System (INIS)

    Konvalina, I.; Muellerova, I.

    2011-01-01

    The cathode lens is an electron optical element in an emission electron microscope accelerating electrons from the sample, which serves as a source for a beam of electrons. Special application consists in using the cathode lens first for retardation of an illuminating electron beam and then for acceleration of reflected as well as secondary electrons, made in the directly imaging low energy electron microscope or in its scanning version discussed here. In order to form a real image, the cathode lens has to be combined with a focusing magnetic lens or a focusing immersion-magnetic lens, as used for objective lenses of some commercial scanning electron microscopes. These two alternatives are compared with regards to their optical properties, in particular with respect to predicted aberration coefficients and the spot size, as well as the optimum angular aperture of the primary beam. The important role of the final aperture size on the image resolution is also presented.

  7. Overview of Beam-Beam Effects in the Tevatron

    CERN Document Server

    Shiltsev, V.

    2014-01-01

    For almost a quarter of a century the Tevatron proton-antiproton collider was the centrepiece of the world's high-energy physics program, from the start of operation in December 1985 until it was overtaken by the LHC in 2011. The initial design luminosity of the Tevatron was 1030 cm-2 s-1; however, as a result of two decades of upgrades, the accelerator has been able to deliver 430-times higher luminosities to each of two high-luminosity experiments, Collider Detector at Fermilab (CDF) and D0. On the way to record high luminosities, many issues related to the electromagnetic beam-beam interaction of colliding beams have been addressed. Below we present a short overview of the beam-beam effects in the Tevatron.

  8. Tevatron-for-LHC Report of the QCD Working Group

    Energy Technology Data Exchange (ETDEWEB)

    Albrow, Michael G.; Begel, M.; Bourilkov, D.; Campanelli, M.; Chlebana, F.; De Roeck, A.; Dittmann, J.R.; Ellis, S.D.; Field, B.; Field, R.; Gallinaro, M.; /Fermilab

    2006-10-01

    The experiments at Run 2 of the Tevatron have each accumulated over 1 fb{sup -1} of high-transverse momentum data. Such a dataset allows for the first precision (i.e. comparisons between theory and experiment at the few percent level) tests of QCD at a hadron collider. While the Large Hadron Collider has been designed as a discovery machine, basic QCD analyses will still need to be performed to understand the working environment. The Tevatron-for-LHC workshop was conceived as a communication link to pass on the expertise of the Tevatron and to test new analysis ideas coming from the LHC community. The TeV4LHC QCD Working Group focused on important aspects of QCD at hadron colliders: jet definitions, extraction and use of Parton Distribution Functions, the underlying event, Monte Carlo tunes, and diffractive physics. This report summarizes some of the results achieved during this workshop.

  9. Constraints on unparticles from top properties measured at Tevatron

    International Nuclear Information System (INIS)

    Islam, Rashidul; Dahiya, Mamta; Dutta, Sukanta

    2013-01-01

    We discuss the recent observations of the top pair production at Tevatron through flavor conserving and flavor violating channels via vector and tensor unparticles. The unparticle sector is considered to be a color singlet or octet. We have used the unparticle propagators modified for full conformal invariance to investigate the contribution of these unparticles to the observed forward backward asymmetry and the spin correlation in top pair production at Tevatron. We also discuss the impact of the flavor violating couplings of unparticles to the third generation quarks on (a) pair production of same sign tops/antitops at TeVatron and (b) the partial top decay width for Γ u (t → uU V )

  10. Tevatron-for-LHC Report of the QCD Working Group

    CERN Document Server

    Albrow, Michael G.; Fermi National Accelerator Laboratory. Batavia; Bourilkov, D.; Campanelli, M.; Chlebana, F.; De Roeck, A.; Dittmann, J.R.; Ellis, S.D.; Field, B.; Field, R.; Gallinaro, M.; Giele, W.; Goulianos, Konstantin A.; Group, R.C.; Hatakeyama, K.; Hubacek, Z.; Huston, J.; Kilgore, W.; Kluge, T.; Lee, S.W.; Moraes, A.; Mrenna, S.; Olness, F.; Proudfoot, J.; Rabbertz, K.; Royon, C.; Sjostrand, T.; Skands, Peter Z.; Smith, J.; Tung, W.K.; Whalley, M.R.; Wobisch, M.; Zielinski, M.

    2006-01-01

    The experiments at Run 2 of the Tevatron have each accumulated over 1 inverse femtobarn of high-transverse momentum data. Such a dataset allows for the first precision (i.e. comparisons between theory and experiment at the few percent level) tests of QCD at a hadron collider. While the Large Hadron Collider has been designed as a discovery machine, basic QCD analyses will still need to be performed to understand the working environment. The Tevatron-for-LHC workshop was conceived as a communication link to pass on the expertise of the Tevatron and to test new analysis ideas coming from the LHC community. The TeV4LHC QCD Working Group focussed on important aspects of QCD at hadron colliders: jet definitions, extraction and use of Parton Distribution Functions, the underlying event, Monte Carlo tunes, and diffractive physics. This report summarizes some of the results achieved during this workshop.

  11. Rare b decays and CP violation at the Tevatron

    Science.gov (United States)

    Ristori, Luciano

    2012-03-01

    The experiments at the Tevatron, CDF and D0, have access to one of the world's largest samples of charm and beauty hadrons decays. These provide information competitive and complementary to that from dedicated flavor facilities. With the analysis of the full Run II data sample, this successful program has now reached its maturity. I review recent Tevatron flavor physics results, focusing on those that are specifically sensitive to departures from the Standard Model, such as searches for rare B decays, measurements of CP-violation in charm, and bottom-strange decays.

  12. Explaining Tevatron leptons photons missing- T events with ...

    Indian Academy of Sciences (India)

    (/ET) signal 3σ in excess of the standard model prediction in Tevatron Run I data. The excess can be explained by the resonant production of a smuon, which subsequently decays to a muon, a photon and a gravitino. Here, we perform combined fits of this model to the CDF 7l/ET excess, the D0 measurement of the same ...

  13. Explaining Tevatron leptons photons missing- T events with ...

    Indian Academy of Sciences (India)

    events with supersymmetry. B C ALLANACH. LAPTH, 9 Chemin de Bellevue, BP 110, 74941 Annecy-le-Vieux, France. Abstract. The CDF experiment reported a lepton photon missing transverse energy. (/ET) signal 3σ in excess of the standard model prediction in Tevatron Run I data. The excess can be explained by the ...

  14. Construction of a new Tevatron collider beam abort dump

    International Nuclear Information System (INIS)

    Hanna, B.; Crawford, C.

    1991-01-01

    As part of the Collider upgrade a new abort system is to be installed in the Tevatron at AO. It consists of two sets of fast kickers and two 90% full aperture graphite beam dumps. This system will abort both protons and antiprotons. Details of the beam dump design and construction are presented

  15. On Self-Similarity of Top Production at Tevatron

    Czech Academy of Sciences Publication Activity Database

    Tokarev, M. V.; Zborovský, Imrich

    2012-01-01

    Roč. 3, č. 8 (2012), s. 815-820 ISSN 2153-120X R&D Projects: GA MŠk LA08002; GA MŠk LA08015 Institutional research plan: CEZ:AV0Z10480505 Keywords : top quark * Tevatron Subject RIV: BE - Theoretical Physics http://www.scirp.org/journal/PaperInformation.aspx?paperID=21690

  16. Race for the Higgs hots up as Tevatron seeks extension

    CERN Multimedia

    Banks, Michael

    2009-01-01

    "With researchers at Cern's Large Hadron Collider (LHC) having circulated protons for the first time since last year's accident, the US Department of Energy (DOE) is requesting $25m so that the Tevatron collider at the Fermi National Accelerator Laboratory in Illinois can run for an extra year until 2011" (0.25 page)

  17. Surge recovery techniques for the Tevatron cold compressors

    International Nuclear Information System (INIS)

    Martinez, A.; Klebaner, A.L.; Makara, J.N.; Theilacker, J.C.; Fermilab

    2006-01-01

    The Fermilab Tevatron cryogenic system utilizes high-speed centrifugal cold compressors, made by Ishikawajima-Harima Heavy Industries Co. Ltd. (IHI), for high-energy operations [1]. The compressor is designed to pump 60 g/s of 3.6 K saturated helium vapor at a pressure ratio of 2.8, with an off-design range of 40 to 70 g/s and operating speeds between 40 and 95 krpm. Since initial commissioning in 1993, Tevatron transient conditions such as quench recovery have led to multiple-location machine trips as a result of the cold compressors entering the surge regime. Historically, compressors operating at lower inlet pressures and higher speeds have been especially susceptible to these machine trips and it was not uncommon to have multiple compressor trips during large multiple-house quenches. In order to cope with these events and limit accelerator down time, surge recovery techniques have been implemented in an attempt to prevent the compressors from tripping once the machine entered this surge regime. This paper discusses the different methods of surge recovery that have been employed. Data from tests performed at the Cryogenic Test Facility at Fermilab as well as actual Tevatron operational data were utilized. In order to aid in the determination of the surge region, a full mapping study was undertaken to characterize the entire pressure field of the cold compressor. These techniques were then implemented and tested at several locations in the Tevatron with some success

  18. Tevatron beam-beam simulations at injection energy

    Energy Technology Data Exchange (ETDEWEB)

    Meiqin Xiao; Bela Erdelyi; Tanaji Sen

    2003-05-28

    Major issues at Tevatron injection are the effects of 72 long-range beam-beam interactions together with the machine nonlinearity on protons and anti-protons. We look at particle tracking calculations of Dynamic Aperture (DA) under present machine conditions. Comparisons of calculations with observations and experiments are also presented in this report.

  19. Experience with the new reverse injection scheme in the Tevatron

    International Nuclear Information System (INIS)

    Saritepe, S.; Goderre, G.; Annala, G.; Hanna, B.; Braun, A.

    1993-01-01

    In the new injection scenario the antiproton beam is injected onto a helical Tevatron orbit to avoid the detrimental effects of the beam-beam interaction at 150 GeV. The new scenario required changes in the tuning procedures. Antiprotons are too precious to be used for tuning, therefore the antiproton injection line has to be tuned with protons by reverse injecting them from the Tevatron into the Main Ring. Previously, the reverse injection was performed in one supercycle. One batch of uncoalesced bunches was injected into the Tevatron and ejected after 40 seconds. The orbit closure was performed in the Main Ring. In the new scheme the lambertson magnets have to be moved, separator polarities have to be switched, activities that cannot be completed in one supercycle. Therefore, the reverse injection sequence was changed. This involved the redefinition of TVBS (Tevatron Beam Synchronized Clock) event $D8 as MRBS (Main Ring Beam Synchronized Clock) $D8 thus making it possible to inject 6 proton batches (or coalesced bunches) and eject them one at a time on command, performing orbit closure each time in the Main Ring

  20. Searches for New Phenomena at the Tevatron and at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Meyer, Arnd

    2006-10-01

    Recent results on searches for new physics at Run II of the Tevatron and highlights from HERA are reported. The searches cover many different final states and a wide range of models. All analyses have at this point led to negative results, but some interesting anomalies have been found.

  1. Tevatron-for-LHC Report: Preparations for Discoveries

    CERN Document Server

    Abdullin, Salavat; Asai, Shoji; Atramentov, Oleksiy Vladimirovich; Baer, Howard; Balazs, Csaba; Bartalini, Paolo; Belyaev, Alexander; Bernhard, Ralf Patrick; Birkedal, Andreas; Buescher, Volker; Cavanaugh, Richard; Chen, Mu-Chun; Clement, Christophe; Datta, AseshKrishna; de Boer, Ytsen R.; De Roeck, Albert; Dobrescu, Bogdan A.; Drozdetskiy, Alexey; Gershtein, Yuri S.; Glenzinski, Douglas A.; Group, Robert Craig; Heinemeyer, Sven; Heldmann, Michael; Hubisz, Jay; Karlsson, Martin; Kong, Kyoungchul; Korytov, Andrey; Kraml, Sabine; Krupovnickas, Tadas; Lafaye, Remi; Lane, Kenneth; Ledroit, Fabienne; Lehner, Frank; Lin, Cheng-Ju; Macesanu, Cosmin; Matchev, Konstantin T.; Menon, Arjun; Milstead, David; Mitselmakher, Guenakh; Morel, Julien; Morrissey, David; Mrenna, Steve; O'Farrill, Jorge; Pakhotin, Yu.; Perelstein, Maxim; Plehn, Tilman; Rainwater, David; Raklev, Are; Schmitt, Michael; Scurlock, Bobby; Sherstnev, Alexander; Skands, Peter Z.; Sullivan, Zack; Tait, Timothy M.P.; Tata, Xerxes; Torchiani, Ingo; Trocme, Benjamin; Wagner, Carlos; Weiglein, Georg; Zerwas, Dirk

    2006-01-01

    This is the "TeV4LHC" report of the "Physics Landscapes" Working Group, focused on facilitating the start-up of physics explorations at the LHC by using the experience gained at the Tevatron. We present experimental and theoretical results that can be employed to probe various scenarios for physics beyond the Standard Model.

  2. Plans for Deployment of Hollow Electron Lenses at the LHC for Enhanced Beam Collimation

    Energy Technology Data Exchange (ETDEWEB)

    Redaelli, S. [CERN; Bertarelli, A. [CERN; Bruce, R. [CERN; Perini, D. [CERN; Rossi, A. [CERN; Salvachua, B. [CERN; Stancari, G. [Fermilab; Valishev, A. [Fermilab

    2015-06-01

    Hollow electron lenses are considered as a possible means to improve the LHC beam collimation system, providing active control of halo diffusion rates and suppressing the population of transverse halos. After a very successful experience at the Tevatron, a conceptual design of a hollow e-lens optimized for the LHC was produced. Recent further studies have led to a mature preliminary technical design. In this paper, possible scenarios for the deployment of this technology at the LHC are elaborated in the context of the scheduled LHC long shutdowns until the full implementation of the HL-LHC upgrade in 2023. Possible setups of electron beam test stands at CERN and synergies with other relevant electron beam programmes are also discussed.

  3. The search for the Higgs at the Tevatron; La recherche du Higgs au Tevatron

    Energy Technology Data Exchange (ETDEWEB)

    Lucotte, A

    2004-07-01

    The Tevatron has undergone an impressive technical renovation program whose final aim is to reach an integrated luminosity of 15 fb{sup -1} per experiment. Both CDF and DO detectors have been upgraded in the fields of detection, triggering, track reconstruction and particle identification. In the framework of the standard model, theoretical studies show that for a luminosity of only 2 fb{sup -1} (that is the first step of the renovation program) CDF and DO could barely extend the domain already excluded by LEP for the existence of the Higgs boson. On the other hand for a luminosity of 15 fb{sup -1}, a standard Higgs boson could be excluded up to 180 GeV/c{sup 2} and discovered up to 125 GeV/c{sup 2}. Moreover, a 3*{sigma} result could be obtained in the decay channels H {yields} bb-bar and H {yields} W{sup +}W{sup -} up to 180 GeV/c{sup 2}. In the framework of the minimal supersymmetric standard model (MSSM), at least 20 fb{sup -1} are required for the discovery of the Higgs boson in the energy range: 80 {<=} m{sub A} {<=} 380 GeV/c{sup 2}. (A.C.)

  4. A Study for Doubly-Charged Higgs Boson at the Tevatron

    Energy Technology Data Exchange (ETDEWEB)

    Baroiant, Sasha [Univ. of California, Davis, CA (United States)

    2006-01-01

    We search for the pair production of doubly charged Higgs particles followed by the lepton-flavor violating decay of each Higgs into electron-and-tau and muonand- tau pairs using 350 pb-1 of data collected by the CDF II experiment at the Fermilab Tevatron. Separate searches investigate cases where three or four finalstate leptons are detected, and the limits for each exclusive decay mode reflect the combined results of both searches. Assuming the H$±±\\atop{L}$ decays exclusively into likesign electron-and-tau pairs, we set a lower limit on its mass of 114 GeV/c2 at the 95 % confidence level. In the case of exclusive muon-and-tau decays, we set a lower mass limit of 112 GeV/c2 also at the 95% confidence level.

  5. A search for double-charged Higgs bosons at the Tevatron

    Energy Technology Data Exchange (ETDEWEB)

    Baraoiant, Sasha [Univ. of California, Davis, CA (United States)

    2006-01-01

    We search for the pair production of doubly charged Higgs particles followed by the lepton-flavor violating decay of each Higgs into electron-and-tau and muon-and-tau pairs using 350 pb-1 of data collected by the CDF II experiment at the Fermilab Tevatron. Separate searches investigate cases where three or four final state leptons are detected, and the limits for each exclusive decay mode reflect the combined results of both searches. Assuming the H$±±\\atop{L}$ decays exclusively into like sign electron-and-tau pairs, we set a lower limit on its mass of 114 GeV/c2 at the 95 % confidence level. In the case of exclusive muon-and-tau decays, we set a lower mass limit of 112 GeV/c2 also at the 95% confidence level.

  6. Evaluation of a new electronic preoperative reference marker for toric intraocular lens implantation by two different methods of analysis: Adobe Photoshop versus iTrace.

    Science.gov (United States)

    Farooqui, Javed Hussain; Sharma, Mansi; Koul, Archana; Dutta, Ranjan; Shroff, Noshir Minoo

    2017-01-01

    The aim of this study is to compare two different methods of analysis of preoperative reference marking for toric intraocular lens (IOL) after marking with an electronic marker. Cataract and IOL Implantation Service, Shroff Eye Centre, New Delhi, India. Fifty-two eyes of thirty patients planned for toric IOL implantation were included in the study. All patients had preoperative marking performed with an electronic preoperative two-step toric IOL reference marker (ASICO AE-2929). Reference marks were placed at 3-and 9-o'clock positions. Marks were analyzed with two systems. First, slit-lamp photographs taken and analyzed using Adobe Photoshop (version 7.0). Second, Tracey iTrace Visual Function Analyzer (version 5.1.1) was used for capturing corneal topograph examination and position of marks noted. Amount of alignment error was calculated. Mean absolute rotation error was 2.38 ± 1.78° by Photoshop and 2.87 ± 2.03° by iTrace which was not statistically significant ( P = 0.215). Nearly 72.7% of eyes by Photoshop and 61.4% by iTrace had rotation error ≤3° ( P = 0.359); and 90.9% of eyes by Photoshop and 81.8% by iTrace had rotation error ≤5° ( P = 0.344). No significant difference in absolute amount of rotation between eyes when analyzed by either method. Difference in reference mark positions when analyzed by two systems suggests the presence of varying cyclotorsion at different points of time. Both analysis methods showed an approximately 3° of alignment error, which could contribute to 10% loss of astigmatic correction of toric IOL. This can be further compounded by intra-operative marking errors and final placement of IOL in the bag.

  7. The Tevatron tune tracker pll - theory, implementation and measurements

    Energy Technology Data Exchange (ETDEWEB)

    Tan, Cheng-Yang; /Fermilab

    2004-12-01

    The Tevatron tune tracker is based on the idea that the transverse phase response of the beam can be measured quickly and accurately enough to allow us to track the betatron tune with a phase locked loop (PLL). The goal of this paper is to show the progress of the PLL project at Fermilab. We will divide this paper into three parts: theory, implementation and measurements. In the theory section, we will use a simple linear model to show that our design will track the betatron tune under conditions that occur in the Tevatron. In the implementation section we will break down and examine each part of the PLL and in some cases calculate the actual PLL parameters used in our system from beam measurements. And finally in the measurements section we will show the results of the PLL performance.

  8. Terascale Beam-Beam Simulations for Tevatron, RHIC and LHC

    Energy Technology Data Exchange (ETDEWEB)

    Qiang, J.

    2005-05-16

    In this paper, we report on recent advances in terascale simulations of the beam-beam interaction in Tevatron, RHIC and LHC.Computational methods for self consistent calculation of beam-beam forces are reviewed. New method for solving the two-dimensional Poisson equation with open boundary conditions is proposed and tested. This new spectral-finite difference method is a factor of four faster than the widely used FFT based Green function method for beam-beam interaction on axis. We also present applications to the study of antiproton losses during the injection stage at Tevatron, to the study of multiple bunch coherent beam-beam modes at RHIC, and to the study of beam-beam driven emittance growth at LHC.

  9. Terascale Beam-Beam Simulations for Tevatron, RHIC and LHC

    International Nuclear Information System (INIS)

    Qiang, J.

    2005-01-01

    In this paper, we report on recent advances in terascale simulations of the beam-beam interaction in Tevatron, RHIC and LHC.Computational methods for self consistent calculation of beam-beam forces are reviewed. New method for solving the two-dimensional Poisson equation with open boundary conditions is proposed and tested. This new spectral-finite difference method is a factor of four faster than the widely used FFT based Green function method for beam-beam interaction on axis. We also present applications to the study of antiproton losses during the injection stage at Tevatron, to the study of multiple bunch coherent beam-beam modes at RHIC, and to the study of beam-beam driven emittance growth at LHC

  10. The A0 abort system for the Tevatron upgrade

    International Nuclear Information System (INIS)

    Crawford, C.

    1989-01-01

    The installation of electrostatic separator modules at B48 and C17 in the Tevatron necessitates changes to the Tevatron abort system. There will no longer be room for either the proton or antiproton kicker magnets used in the present system. The kickers at C17 will be permanently removed. The kickers at B48 will be temporarily removed for collider operation and will be replaced for fixed target operation. The existing proton abort system will remain unchanged during fixed target operation. This note describes a proposed abort system for operation in the collider mode for 22 on 22 bunches and provides details of specifications for the required components. In certain cases, for example in the case of the pulsers for the magnets and the absorber assembly, system components are designed with the option of upgrading to 44 on 44 bunch operation in mind. 8 refs., 14 figs

  11. Searches for New Physics at the Tevatron and LHC

    Energy Technology Data Exchange (ETDEWEB)

    Wittich, Peter; /Cornell U., LEPP

    2011-11-01

    This is an auspicious moment in experimental particle physics - there are large data samples at the Tevatron and a new energy regime being explored at the Large Hadron Collider with ever larger data samples. The coincidence of these two events suggests that we will soon be able to address the question, what lies beyond the standard model? Particle physics's current understanding of the universe is embodied in it. The model has been tested to extreme precision - better than a part in ten thousand - but we suspect that it is only an approximation, and that physics beyond this standard model will appear in the data of the Tevatron and LHC in the near future. This brief review touches on the status of searches for new physics at the time of the conference.

  12. Searches for BSM (non-SUSY) physics at the Tevatron

    Energy Technology Data Exchange (ETDEWEB)

    Gerberich, Heather K.; /Illinois U., Urbana

    2005-11-01

    As of July 2005, the Tevatron at Fermilab has delivered {approx} 1 fb{sup -1} of data to the CDF and D0 experiments. Each experiment has recorded more than 80% of the delivered luminosity. Results of searches for physics (non-SUSY and non-Higgs) beyond the Standard Model using 200 pb{sup -1} to 480 pb{sup -1} at D0 and CDF are presented.

  13. Programmable high power beam damper for the Tevatron

    International Nuclear Information System (INIS)

    Crisp, J.; Goodwin, R.; Gerig, R.

    1985-06-01

    A bunch-by-bunch beam damper has been developed for the Fermilab Tevatron. The system reduces betatron oscillation amplitudes and incorporates some useful machine diagnostics. The device is programmable via look-up tables so the output is an arbitrary function, on a bunch-by-bunch basis, of the beam displacement. We are presently using this feature to measure the betatron tune throughout the acceleration cycle. 4 refs

  14. Review of Physics Results from the Tevatron: Top Quark Physics

    Energy Technology Data Exchange (ETDEWEB)

    Gerber, Cecilia E.; Vellidis, Costas

    2014-09-17

    We present results on top quark physics from the CDF and D0 collaborations at the Fermilab Tevatron proton anti-proton collider. These include legacy results from Run II that were published or submitted for publication before mid-2014, as well as a summary of Run I results. The historical perspective of the discovery of the top quark in Run I is also described.

  15. Higgs decay to bottom quarks at the Tevatron

    International Nuclear Information System (INIS)

    Stange, A.; Marciano, W.; Willenbrock, S.

    1993-10-01

    We study the production and detection of the standard-model Higgs boson at the Fermilab Tevatron. The most promising mode is WH and ZH associated production followed by leptonic decay of the weak vector bosons and H → b bar b. It may be possible to detect a Higgs boson of mass m H = 60--80 GeV with 1000 pb -1 of integrated luminosity

  16. Search for Low Mass Higgs Boson at the Tevatron

    Energy Technology Data Exchange (ETDEWEB)

    Totaro, Pierluigi [Padua U.

    2012-09-01

    We present the current status of searches for a low mass Standard Model Higgs boson (M_H below ~ 135 GeV/c^2) using data collected from ppbar collisions at the Fermilab Tevatron collider at \\sqrt{s}= 1.96 TeV. A summary of the latest results from the CDF and D0 collaborations is reported in this paper, focusing in particular on ongoing efforts to increase overall search sensitivity through improvements to the analysis methods.

  17. Tevatron-for-LHC Report: Preparations for Discoveries

    Energy Technology Data Exchange (ETDEWEB)

    Buescher, V.; Carena, Marcela S.; Dobrescu, Bogdan A.; Mrenna, S.; Rainwater, D.; Schmitt, M.

    2006-08-01

    This is the ''TeV4LHC'' report of the ''Physics Landscapes'' Working Group, focused on facilitating the start-up of physics explorations at the LHC by using the experience gained at the Tevatron. We present experimental and theoretical results that can be employed to probe various scenarios for physics beyond the Standard Model.

  18. OVERVIEW OF HIGGS BOSON STUDIES AT THE TEVATRON

    Energy Technology Data Exchange (ETDEWEB)

    Zivkovic, Lidija [Institute of Physics, Zemun, Serbia

    2014-05-01

    The CDF and D0 experiments at the Tevatron p¯p Collider collected data between 2002 and 2011, accumulating up to 10 fb-1 of data. During that time, an extensive search for the standard model Higgs boson was performed. Combined results from the searches for the standard model Higgs boson with the final dataset are presented, together with results on the Higgs boson couplings and spin and parity.

  19. Present searches for Higgs signatures at the Tevatron

    International Nuclear Information System (INIS)

    Groer, L.

    1997-08-01

    We present results for various searches for signatures of standard and non-standard model Higgs boson decays conducted at the collider detectors CDF and D0 using ∼100 pb -1 of integrated luminosity each from the Tevatron collider Run 1 (1992-96) at √s=1.8 TeV. No evidence for a Higgs boson decay is found and various limits are set

  20. Pressure Field Study of the Tevatron Cold Compressors

    International Nuclear Information System (INIS)

    Klebaner, A.L.; Martinez, A.; Soyars, W.M.; Theilacker, J.C.

    2004-01-01

    The Fermilab Tevatron cryogenic system utilizes high-speed centrifugal cold compressors, manufactured by Ishikawajima-Harima Heavy Industries Co. Ltd. (IHI), for high-energy operations. The compressor is designed to pump 60 g/sec of 3.6 K saturated helium vapor at a pressure ratio of 2.8, with an off-design range of 40 to 70 g/sec. Operating speeds are between 40,000 and 95,000 rpm, with a speed of 80,000 rpm at the design point. Different heat loads and magnet quench performance of each of the twenty-four satellite refrigerators dictates different process pressure and flow rates of the cold compressors. Reducing the process flow rate can cause the centrifugal cold compressor to stop pumping and subsequently surge. Tests have been conducted at the Cryogenic Test Facility at Fermilab to map the pressure field and appropriate efficiency of the IHI hydrodynamic cold compressor. The information allows tuning of each of the twenty-four Tevatron satellite refrigerators to avoid cold compressor operation near the surge and choke lines. A new impeller has also been tested. The Tevatron cold compressor pressure field and efficiency data with the new impeller are presented in this paper

  1. Cryogenic testing and analysis associated with Tevatron lower temperature operation

    International Nuclear Information System (INIS)

    Theilacker, J.C.

    1996-01-01

    An upgrade of the Tevatron cryogenic system was installed and commissioned in 1993 to allow lower temperature operation. As a result, higher energy operation of the Fermilab superconducting Tevatron accelerator is possible. Following the installation and initial commissioning, it was decided to continue the current colliding beam physics run at the previous energy of 900 GeV. This has allowed the author to perform parasitic lower temperature tests in the Tevatron over the last year and a half. This paper presents the results of operational experiences and thermal and hydraulic testing which have taken place. The primary goal of the testing is to better understand the operation of the cold compressor system, associated instrumentation, and the performance of the existing magnet system during lower temperature operation. This will lead to a tentatively scheduled higher energy test run in the fall of 1995. The test results have shown that more elaborate controlling methods are necessary in order to achieve reliable system operation. Fortunately, the new satellite refrigerator controls system is capable of the expansion necessary to reach this goal. New features are being added to the controls systems which will allow for more intelligent control and better diagnostics for component monitoring and trending

  2. Contact lens in keratoconus

    Directory of Open Access Journals (Sweden)

    Varsha M Rathi

    2013-01-01

    Full Text Available Contact lenses are required for the visual improvement in patients with keratoconus. Various contact lens options, such as rigid gas permeable (RGP lenses, soft and soft toric lenses, piggy back contact lenses (PBCL, hybrid lenses and scleral lenses are availble. This article discusses about selection of a lens depending on the type of keratoconus and the fitting philosophies of various contact lenses including the starting trial lens. A Medline search was carried out for articles in the English language with the keywords keratoconus and various contact lenses such as Rose k lens, RGP lens, hybrid lens, scleral lens and PBCL.

  3. Contact lens in keratoconus

    Science.gov (United States)

    Rathi, Varsha M; Mandathara, Preeji S; Dumpati, Srikanth

    2013-01-01

    Contact lenses are required for the visual improvement in patients with keratoconus. Various contact lens options, such as rigid gas permeable (RGP) lenses, soft and soft toric lenses, piggy back contact lenses (PBCL), hybrid lenses and scleral lenses are availble. This article discusses about selection of a lens depending on the type of keratoconus and the fitting philosophies of various contact lenses including the starting trial lens. A Medline search was carried out for articles in the English language with the keywords keratoconus and various contact lenses such as Rose k lens, RGP lens, hybrid lens, scleral lens and PBCL. PMID:23925325

  4. Resonant second generation slepton production at the Tevatron

    Energy Technology Data Exchange (ETDEWEB)

    Autermann, Christian Tobias [RWTH Aachen Univ. (Germany)

    2006-12-01

    A search for R-parity violating supersymmetry with the D0 detector at the Fermilab Tevatron p$\\bar{p}$-collider is presented. Assuming a non-zero LQ$\\bar{d}$ coupling λ$'\\atop{2jk}$ leads to final state with two muons and jets. A total integrated luminosity of 375 pb-1 collected between April 2002 and August 2004 is utilized. The observed number of events is in agreement with the Standard Model expectation, and limits on Rp supersymmetry are derived.

  5. $B$ physics at the Tevatron: Run II and beyond

    CERN Document Server

    Anikeev, K; Azfar, F.; Bailey, S.; Bauer, C.W.; Bell, W.; Bodwin, G.; Braaten, E.; Burdman, G.; Butler, J.N.; Byrum, K.; Cason, N.; Cerri, A.; Cheung, H.W.K.; Dighe, A.; Donati, S.; Ellis, R.K.; Falk, A.; Feild, G.; Fleming, S.; Furic, I.; Gardner, S.; Grossman, Y.; Gutierrez, G.; Hao, W; Harris, B.W.; Hewett, J.; Hiller, G.; Jesik, R.; Jones, M.; Kasper, P.A.; El-Khadra, A.; Kirk, M.; Kiselev, V.V.; Kroll, J.; Kronfeld, A.S.; Kutschke, R.; Kuznetsov, V.E.; Laenen, E.; Lee, J.; Leibovich, A.K.; Lewis, J.D.; Ligeti, Z.; Likhoded, A.K.; Logan, H.E.; Luke, M.; Maciel, A.; Majumder, G.; Maksimovic, P.; Martin, M.; Menary, S.; Nason, P.; Nierste, U.; Nir, Y.; Nogach, L.; Norrbin, E.; Oleari, C.; Papadimitriou, V.; Paulini, M.; Paus, C.; Petteni, M.; Poling, R.; Procario, M.; Punzi, G.; Quinn, H.; Rakitine, A.; Ridolfi, G.; Shestermanov, K.; Signorelli, G.; Silva, J.P.; Skwarnicki, T.; Smith, A.; Speakman, B.; Stenson, K.; Stichelbaut, F.; Stone, S.; Sumorok, K.; Tanaka, M.; Taylor, W.; Trischuk, W.; Tseng, J.; Van Kooten, R.; Vasiliev, A.; Voloshin, M.; Wang, J.C.; Wicklund, A.B.; Wurthwein, F.; Xuan, N.; Yarba, J.; Yip, K.; Zieminski, A.

    2002-01-01

    This report provides a comprehensive overview of the prospects for B physics at the Tevatron. The work was carried out during a series of workshops starting in September 1999. There were four working groups: 1) CP Violation, 2) Rare and Semileptonic Decays, 3) Mixing and Lifetimes, 4) Production, Fragmentation and Spectroscopy. The report also includes introductory chapters on theoretical and experimental tools emphasizing aspects of B physics specific to hadron colliders, as well as overviews of the CDF, D0, and BTeV detectors, and a Summary.

  6. Studies of top quark properties at the Tevatron

    Energy Technology Data Exchange (ETDEWEB)

    Shary, Viatcheslav

    2012-05-01

    An overview of the recent measurements of the top quark properties in proton antiproton collisions at {radical}s = 1.96 TeV is presented. These measurements are based on 5.4-8.7 fb{sup -1} of data collected with the D0 and CDF experiments at the Fermilab Tevatron collider. The top quark mass and width measurements, studies of the spin correlation in top quark pair production, W boson helicity measurement, searches for anomalous top quark couplings and Lorentz invariance violation are discussed.

  7. Spectroscopy and Decay of $B$ Hadrons at the Tevatron

    Energy Technology Data Exchange (ETDEWEB)

    Paulini, Manfred

    2007-02-01

    The authors review recent results on heavy quark physics focusing on Run II measurements of B hadron spectroscopy and decay at the Tevatron. A wealth of new B physics measurements from CDF and D0 has been available. These include the spectroscopy of excited B states (B**, B**{sub s}) and the observation of the {Sigma}{sub b} baryon. The discussion of the decays of B hadrons and measurements of branching fractions focuses on charmless two-body decays of B {yields} h{sup +}h{sup -}. They report several new B{sub s}{sup 0} and {Lambda}{sub b}{sup 0} decay channels.

  8. Online calculation of the Tevatron collider luminosity using accelerator instrumentation

    International Nuclear Information System (INIS)

    Hahn, A.A.

    1997-07-01

    The luminosity of a collision region may be calculated if one understands the lattice parameters and measures the beam intensities, the transverse and longitudinal emittances, and the individual proton and antiproton beam trajectories (space and time) through the collision region. This paper explores an attempt to make this calculation using beam instrumentation during Run 1b of the Tevatron. The instrumentation used is briefly described. The calculations and their uncertainties are compared to luminosities calculated independently by the Collider Experiments (CDF and D0)

  9. Minimax: Multiparticle physics at the TeVatron collider

    International Nuclear Information System (INIS)

    Bjorken, J.D.

    1994-01-01

    The author and two dozen others are engaged in a small test/experiment in the Fermilab Tevatron collider. It is called Minimax, and its purpose is to explore large-cross-section physics in the forward direction. The primary goal of Minimax is search for events containing the residue of disoriented chiral condensate (dcc) produced in the primary collision. The theoretical ideas are very speculative. But if they are right, they could provide an interpretation of the Centauro/anti-Centauro anomalies claimed to have been seen in cosmic-ray events. In this paper, the history and status of Minimax is described

  10. High intensity beam dump for the Tevatron beam abort system

    International Nuclear Information System (INIS)

    Kidd, J.; Mokhov, N.; Murphy, T.; Palmer, M.; Toohig, T.; Turkot, F.; VanGinneken, A.

    1981-01-01

    The beam abort system proposed for the Fermilab Tevatron Accelerator will extract the proton beam from the ring in a single turn (approximately 20/mu/s) and direct it to an external beam dump. It is the function of the beam dump to absorb the unwanted beam and limit the escaping radiation to levels that are acceptable to the surrounding populace and apparatus. A beam dump that is expected to meet these requirements has been designed and constructed. Detailed design of the dump, including considerations leading to the choice of materials, are given. 6 refs

  11. Single and Double Top Quark Production at the Tevatron

    Energy Technology Data Exchange (ETDEWEB)

    Wicke, Daniel; CDF, for the; collaborations, D0

    2010-06-01

    The CDF and D0 experiments have measured single and double top quark production in ppbar collisions at the Tevatron at a centre-of-mass energy of 1.96TeV. The applied methods are used to constrain properties of the top quark and to search for new physics. Several methods of signal to background separation and of the estimation of the background contributions are discussed. Experimental results using an integraged luminosity up to 5.3fb{sup -1} are presented.

  12. Measurements of top quark production and properties at the Tevatron

    Energy Technology Data Exchange (ETDEWEB)

    Bartos, P. [Comenius U.

    2014-09-15

    In this letter, we summarize the latest results of the top-quark production and properties at the Tevatron. We do not include results of the top-quark mass and single top-quark production as they were presented in separate talks. The results of the measurements are mostly consistent with the standard-model predictions. However, by looking at the production asymmetry measured by CDF, one can see a discrepancy in both, $t\\bar{t}$ inclusive and lepton-based measurements. D\\O\\ results of production asymmetry are compatible with the standard-model predictions as well as with the CDF results.

  13. High Mass Standard Model Higgs searches at the Tevatron

    Directory of Open Access Journals (Sweden)

    Petridis Konstantinos A.

    2012-06-01

    Full Text Available We present the results of searches for the Standard Model Higgs boson decaying predominantly to W+W− pairs, at a center-of-mass energy of √s = 1.96 TeV, using up to 8.2 fb−1 of data collected with the CDF and D0 detectors at the Fermilab Tevatron collider. The analysis techniques and the various channels considered are discussed. These searches result in exclusions across the Higgs mass range of 156.5< mH <173.7 GeV for CDF and 161< mH <170 GeV for D0.

  14. Minimax: Multiparticle physics at the TeVatron collider

    Energy Technology Data Exchange (ETDEWEB)

    Bjorken, J.D.

    1994-01-01

    The author and two dozen others are engaged in a small test/experiment in the Fermilab Tevatron collider. It is called Minimax, and its purpose is to explore large-cross-section physics in the forward direction. The primary goal of Minimax is search for events containing the residue of disoriented chiral condensate (dcc) produced in the primary collision. The theoretical ideas are very speculative. But if they are right, they could provide an interpretation of the Centauro/anti-Centauro anomalies claimed to have been seen in cosmic-ray events. In this paper, the history and status of Minimax is described.

  15. J/ψ production: Tevatron and fixed-target collisions

    International Nuclear Information System (INIS)

    Petrelli, A.

    1999-01-01

    In this talk the author shows the results of a fit of the NRQCD matrix elements to the CDF data for direct J/ψ production, by including the radiative corrections to the g g > 3 S 1 [1] channel and the effect of the k T -smearing. Furthermore he performs the NLO NRQCD analysis of J/ψ production in fixed-target proton-nucleon collisions and he fits the colour-octet matrix elements to the available experimental data. The results are compared to the Tevatron ones

  16. Top quark production and properties at the Tevatron

    Energy Technology Data Exchange (ETDEWEB)

    Fiedler, Frank; /Munich U.

    2005-06-01

    The precise measurement of top quark production and properties is one of the primary goals of the Tevatron during Run II. The total t{bar t} production cross-section has been measured in a large variety of decay channels and using different selection criteria. Results from differential cross-section measurements and searches for new physics in t{bar t} production and top quark decays are available. Electroweak production of single top quarks has been searched for. The results from all these analyses, using typically 200 pb{sup -1} of data, are presented.

  17. Top Production at the Tevatron: The Antiproton Awakens

    Energy Technology Data Exchange (ETDEWEB)

    Bloom, Kenneth [Nebraska U.

    2017-07-01

    A long time ago, at a laboratory far, far away, the Fermilab Tevatron collided protons and antiprotons at $\\sqrt{s} = 1.96$ TeV. The CDF and D0 experiments each recorded datasets of about 10 fb$^{-1}$. As such experiments may never be repeated, these are unique datasets that allow for unique measurements. This presentation describes recent results from the two experiments on top-quark production rates, spin orientations, and production asymmetries, which are all probes of the $p\\bar{p}$ initial state.

  18. Review of physics results from the Tevatron: QCD physics

    Energy Technology Data Exchange (ETDEWEB)

    Mesropian, Christina [Rockefeller U.; Bandurin, Dmitry [Virginia U.

    2015-02-17

    We present a summary of results from studies of quantum chromodynamics at the Fermilab Tevatron collider by the CDF and the D0 experiments. These include Run II results for the time period up to the end of Summer 2014. A brief description of Run I results is also given. This review covers a wide spectrum of topics, and includes measurements with jet and vector boson final states in the hard (perturbative) energy regime, as well as studies of soft physics such as diffractive and elastic scatterings, underlying and minimum bias events, hadron fragmentation, and multiple parton interactions.

  19. Acanthamoeba, bacterial, and fungal contamination of contact lens storage cases.

    Science.gov (United States)

    Gray, T B; Cursons, R T; Sherwan, J F; Rose, P R

    1995-01-01

    BACKGROUND--Microbial corneal infection is the most serious complication of contact lens wear. Contact lens cases are a recognised potential source of pathogens associated with corneal ulcers. METHODS--This survey established the incidence of protozoal, bacterial, and fungal contact lens case contamination in 101 asymptomatic daily wear cosmetic contact lens wearers from a domiciliary contact lens practice. RESULTS--Eighty two (81%) contact lens cases were found to be contaminated, with 19 (19%) sterile. Of all contact lens cases, 78 (77%) grew bacteria, 24 (24%) fungi, and 20 (20%) protozoa. Acanthamoeba spp were isolated from eight (8%) contact lens cases. Fifty six (55%) contact lens cases yielded mixed bacterial contamination. This is the first contact lens case survey in which hydrogen peroxide disinfection was the major method of contact lens disinfection (75% of subjects) and no home made saline was used. All the contaminating organisms were shown to possess the enzyme catalase that breaks down hydrogen peroxide to oxygen and water. The polymicrobial nature of the biofilms found in many contact lens cases is illustrated electron micrographically. CONCLUSION--Based on data from this and previous studies, the authors conclude with recommendations for contact lens wearers: (1) regular scrubbing of contact lens case interior to disrupt biofilms; (2) exposure of contact lens case to very hot water (> or = 70 degrees C) will kill Acanthamoeba contaminants; (3) allow contact lens case to air dry between uses; (4) if hydrogen peroxide disinfection is preferred, use a two step system; (5) replace contact lens case regularly. Images PMID:7626578

  20. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... lens because they can be purchased over-the-counter or on the Internet," says Thomas Steinemann, MD, ... Halloween Safety Colored Contact Lens Facts Over-the-Counter Costume Contacts May Contain Chemicals Harmful to Eyes ...

  1. Gabor lens theory

    International Nuclear Information System (INIS)

    Irani, A.A.

    1978-01-01

    The principle of using the space charge of an electron cloud to focus ion beams was first proposed by Gabor. Electrons are to be confined radially by means of an axial magnetic field B/sub z/ and axially by means of externally applied electric fields E/sub z/. An ion beam of charge density n/sub i/ much less than n/sub e/, the electron charge density can then be focused by the radial electric field set up by the electron cloud. The case considered here is that of a hollow cylindrical conductor charged to a potential +V with grounded rings on either side to set up the axial E/sub z/ field. A solenoid wound around the central conductor supplies the B/sub z/ field. Theoretical calculations are carried out for n/sub e/ maximum as a function of B/sub z/ due to radial confinement and V due to axial confinement and the focal length of the Gabor Lens is calculated

  2. A Disoriented Chiral Condensate Search at the Fermilab Tevatron

    Energy Technology Data Exchange (ETDEWEB)

    Convery, Mary Elizabeth [Case Western Reserve U.

    1997-05-01

    MiniMax (Fermilab T-864) was a small test/experiment at the Tevatron designed to search for disoriented chiral condensates (DCC) in the forward direction. The MiniMax detector at the C0 collision region of the Tevatron was a telescope of 24 multi-wire proportional chambers (MWPC's) with a lead converter behind the eighth MWPC, allowing the detection of charged particles and photon conversions in an acceptance approximately a circle of radius 0.6 in pseudorapidity-azimuthal-angle space, centered on a pseudorapidity of about 4. The use of standard Monte Carlo simulations (PYTHIA, GEANT) is described, along with the simulation created by the MiniMax Collaboration to generate DCC domains. A description of the data analysis software is given, including detailed studies of its performance on data from the simulations. A set of robust observables is derived. These are insensitive to many efficiencies and to the details of the modeling of the parent pion production mechanisms, yet have distinguishable values for DCC and generic charged-neutral distributions. Simulations show that the robust observables are insensitive to detector efficiencies and to systematic errors in the data analysis software. The resulting values for robust observables for approximately 1.5 million events are shown to be consistent with production by only generic mechanisms. Results from samples of diffractive-tagged events and of high-multiplicity events also show no evidence for DCC.

  3. In celebration of the fixed target program with the Tevatron

    Energy Technology Data Exchange (ETDEWEB)

    Jeffrey A. Appel et al.

    2001-12-28

    The Tevatron is the world's first large superconducting accelerator. With its construction, we gained the dual opportunities to advance the state of the art in accelerator technology with the machine itself and in particle physics with the experiments that became possible in a higher energy regime. There have been 43 experiments in the Tevatron fixed target program. Many of these are better described as experimental programs, each with a broad range of physics goals and results, and more than 100 collaborating physicists and engineers. The results of this program are three-fold: (1) new technologies in accelerators, beams and detectors which advanced the state of the art; (2) new experimental results published in the refereed physics journals; and (3) newly trained scientists who are both the next generation of particle physicists and an important part of the scientific, technical and educational backbone of the country as a whole. In this book they compile these results. There are sections from each experiment including what their physics goals and results were, what papers were published, and which students have received degrees. Summaries of these results from the program as a whole are quite interesting, but the physics results from this program are too broad to summarize globally. The most important of the results appear in later sections of this booklet.

  4. In celebration of the fixed target program with the Tevatron

    International Nuclear Information System (INIS)

    Appel, Jeffrey A.

    2001-01-01

    The Tevatron is the world's first large superconducting accelerator. With its construction, we gained the dual opportunities to advance the state of the art in accelerator technology with the machine itself and in particle physics with the experiments that became possible in a higher energy regime. There have been 43 experiments in the Tevatron fixed target program. Many of these are better described as experimental programs, each with a broad range of physics goals and results, and more than 100 collaborating physicists and engineers. The results of this program are three-fold: (1) new technologies in accelerators, beams and detectors which advanced the state of the art; (2) new experimental results published in the refereed physics journals; and (3) newly trained scientists who are both the next generation of particle physicists and an important part of the scientific, technical and educational backbone of the country as a whole. In this book they compile these results. There are sections from each experiment including what their physics goals and results were, what papers were published, and which students have received degrees. Summaries of these results from the program as a whole are quite interesting, but the physics results from this program are too broad to summarize globally. The most important of the results appear in later sections of this booklet

  5. A disoriented chiral condensate search at the Fermilab Tevatron

    International Nuclear Information System (INIS)

    Convery, M.E.

    1997-05-01

    MiniMax (Fermilab T-864) was a small test/experiment at the Tevatron designed to search for disoriented chiral condensates (DCC) in the forward direction. Relativistic quantum field theory treats the vacuum as a medium, with bulk properties characterized by long-range order parameters. This has led to suggestions that regions of open-quotes disoriented vacuumclose quotes might be formed in high-energy collision processes. In particular, the approximate chiral symmetry of QCD could lead to regions of vacuum which have chiral order parameters disoriented to directions which have non-zero isospin, i.e. disoriented chiral condensates. A signature of DCC is the resulting distribution of the fraction of produced pions which are neutral. The MiniMax detector at the C0 collision region of the Tevatron was a telescope of 24 multi-wire proportional chambers (MWPC's) with a lead converter behind the eighth MWPC, allowing the detection of charged particles and photon conversions in an acceptance approximately a circle of radius 0.6 in pseudorapidity-azimuthal-angle space, centered on pseudorapidity η ∼ 4. An electromagnetic calorimeter was located behind the MWPC telescope, and hadronic calorimeters and scintillator were located in the upstream anti-proton direction to tag diffractive events

  6. Review of Physics Results from the Tevatron: Higgs Boson Physics

    International Nuclear Information System (INIS)

    Junk, Thomas R.; Juste, Aurelio

    2015-01-01

    We review the techniques and results of the searches for the Higgs boson performed by the two Tevatron collaborations, CDF and DO. The Higgs boson predicted by the Standard Model was sought in the mass range 90 GeVTevatron: gluon-gluon fusion, WH and ZH associated production, vector boson fusion, and tt ¯ H production, and in five main decay modes: H→bb ¯ , H→τ + τ − , H→WW (∗) , H→ZZ (∗) , and H→γγ . An excess of events was seen in the H→bb ¯ searches consistent with a Standard Model Higgs boson with a mass in the range 115 GeV

  7. Cryogenic testing and analysis associated with Tevatron lower temperature operation

    International Nuclear Information System (INIS)

    Theilacker, J.C.

    1996-09-01

    An upgrade of the Tevatron cryogenic system was installed and commissioned in 1993 to allow lower temperature operation. As a result, higher energy operation is possible. Following the installation and initial commissioning, it was decided to continue the current colliding beam physics at the previous energy of 900 GeV. This has allowed us to perform parasitic lower temperature tests in the Tevatron over the last year and a half. This paper presents the results of operational experiences and thermal and hydraulic testing which has taken place. The primary goal of the testing is to better understand the operation of the cold compressor system, associated instrumentation, and the performance of the existing magnet system during lower temperature operation. This will lead to a tentatively scheduled higher energy test run in the fall of 1995. The test results have shown that more elaborate controlling methods are necessary in order to achieve reliable system operation. Fortunately, our new satellite refrigerator controls system is capable of the expansion necessary to reach our goal. New features are being added to the control system which will allow for more intelligent control and better diagnostics for component monitoring and trending

  8. Position sensitive silicon detectors inside the Tevatron collider

    International Nuclear Information System (INIS)

    Apollinari, G.; Bedeschi, F.; Bellettini, G.; Bosi, F.; Bosisio, L.; Cervelli, F.; Del Fabbro, R.; Dell'Orso, M.; Di Virgilio, A.; Focardi, E.; Giannetti, P.; Giorgi, M.; Menzione, A.; Ristori, L.; Scribano, A.; Sestini, P.; Stefanini, A.; Tonelli, G.; Zetti, F.; Bertolucci, S.; Cordelli, M.; Curatolo, M.; Dulach, B.; Esposito, B.; Giromini, P.; Miscetti, S.; Sansoni, A.

    1986-01-01

    Four position sensitive silicon detectors have been tested inside the Tevatron beam pipe at Fermilab. The system is the prototype of the small angle silicon spectrometer designed to study primarily p-anti p elastic and diffractive cross-sections at the Collider of Fermilab (CDF). Particles in the beam halo during p-anti p storage tests were used to study the performance of the detectors. Efficiency, linearity of response and spatial resolution are shown. Measurements performed at different distances from the beam axis have shown that the detectors could be operated at 8.5 mm from the beam with low rates and no disturbance to the circulating beams. This distance corresponds to about 11 times the standard half-width of the local beam envelope. The behaviour of the detectors with the radiation dose has also been investigated. (orig.)

  9. Semileptonic decays of the Higgs boson at the Tevatron

    CERN Document Server

    Lykken, Joseph D; Winter, Jan-Christopher

    2012-01-01

    We examine the prospects for extending the Tevatron reach for a Standard Model Higgs boson by including the semileptonic Higgs boson decays h --> WW --> l nu jj for M_h >~ 2 M_W, and h --> W jj --> l nu jj for M_h <~ 2 M_W, where j is a hadronic jet. We employ a realistic simulation of the signal and backgrounds using the Sherpa Monte Carlo event generator. We find kinematic selections that enhance the signal over the dominant W+jets background. The resulting sensitivity could be an important addition to ongoing searches, especially in the mass range 120 <~ M_h <~ 150 GeV. The techniques described can be extended to Higgs boson searches at the Large Hadron Collider.

  10. Searches for New Physics in Top Events at the Tevatron

    Energy Technology Data Exchange (ETDEWEB)

    Jung, A.W.; /Fermilab

    2012-06-01

    Recent results of searches for new physics in top events at the Tevatron are presented. In case of CDF three searches are discussed using 6 to 8.7 fb{sup -1} of data, with the latter being the final CDF data sample available for this kind of analysis. CDF carried out a search for Top + jet resonance production, dark matter production in association with single top and boosted tops. No signs of new physics are observed and instead upper limits are derived. D0 used 5.3 fb{sup -1} of data and searched for a narrow resonance in t{bar t} production and a time dependent t{bar t} cross section, which would reveal a violation of Lorentz invariance. However, no signs for deviations from standard model are seen and instead upper limits for non-standard model contributions are calculated.

  11. Top-quark mass measurements: Alternative techniques (LHC + Tevatron)

    CERN Document Server

    Adomeit, Stefanie; The ATLAS collaboration

    2014-01-01

    Measurements of the top-quark mass employing alternative techniques are presented, performed by the D0 and CDF collaborations at the Tevatron as well as the ATLAS and CMS experiments at the LHC. The alternative methods presented include measurements using the lifetime of $B$-hadrons, the transverse momentum of charged leptons and the endpoints of kinematic distributions in top quark anti-quark pair ($t\\bar{t}$) final states. The extraction of the top-quark pole mass from the $t\\bar{t}$ production cross-section and the normalized differential $t\\bar{t}$ + 1-jet cross-section are discussed as well as the top-quark mass extraction using fixed-order QCD predictions at detector level. Finally, a measurement of the top-quark mass using events enhanced in single top t-channel production is presented.

  12. Initial tests of an AC dipole for the Tevatron

    Energy Technology Data Exchange (ETDEWEB)

    Miyamoto, R.; /Texas U.; Jansson, A.; /Fermilab; Kopp, S.; /Texas U.; Syphers, M.; /Fermilab

    2006-06-01

    The AC dipole is a device to diagnose transverse motions of a beam. It can achieve large-amplitude oscillations without two inevitable problems of conventional kicker/pinger magnets: decoherence and emittance growth. While not the first synchrotron to operate with an AC dipole, the Tevatron can now make use of its recently upgraded BPM system, providing unprecedented resolution for use with an AC dipole, to measure both linear and nonlinear properties of the accelerator. Plans are to provide AC dipole systems for both transverse degrees of freedom. Preliminary tests have been done using an audio power amplifier with an existing vertical pinger magnet, producing oscillation amplitudes up to 2{sigma} at 150 GeV. In this paper, we will present the configuration of this system. We also show the analysis of a first few data sets, including the direct measurement of beta functions at BPM locations.

  13. Searches for Long-lived Particles at the Tevatron Collider

    International Nuclear Information System (INIS)

    Adams, T.; Florida State U.

    2008-01-01

    Several searches for long-lived particles have been performed using data from p(bar p) collisions from Run II at the Tevatron. In most cases, new analysis techniques have been developed to carry out each search and/or estimate the backgrounds. These searches expand the discovery potential of the CDF and D0 experiments to new physics that may have been missed by traditional search techniques. This review discusses searches for (1) neutral, long-lived particles decaying to muons, (2) massive, neutral, long-lived particles decaying to a photon and missing energy, (3) stopped gluinos, and (4) charged massive stable particles. It summarizes some of the theoretical and experimental motivations for such searches

  14. W/Z + Jets production at the Tevatron

    International Nuclear Information System (INIS)

    Yu, J.

    1995-07-01

    Both the D0 and CDF experiments at Fermilab Tevatron collider at √s = 1.8 TeV have accumulated over 50pb -1 of data. Each experiment collected more than 50,000 W → l +v and 5000 Z → l + bar l candidates for each lepton species (e and μ). Using this large data sample of W and Z candidates, the two experiments are actively testing perturbative QCD predictions. Among the studies that are in progress, preliminary results of W/Z+jets characteristics, multiplicity distributions of associated jets, and a study on the determination of the strong coupling constant using the ratio of the W+1 jet to W + 0 jet cross sections are presented

  15. Review of top quark production at LHC and Tevatron

    CERN Document Server

    AUTHOR|(INSPIRE)INSPIRE-00419409; The ATLAS collaboration

    2016-01-01

    A summary of recent results on top quark production at LHC and Tevatron are presented in this paper. The measurements of top quark production were performed in various energies ($\\sqrt s$ = 1.96, 7, 8, 13 TeV) and initial states ($p \\bar{p}$ and $p p$) by the ATLAS, CDF, CMS, DØ and LHCb ex- periments. The measured top quark pair production cross-section is in good agreement with the standard model predictions in each energy region. Differential cross-sections were also measured and compared with several theoretical predictions. Most of the higher order QCD models reproduce the experimental data well, while a slight discrepancy in a certain phase space such as higher top quark $p_{T}$ region is observed. Electroweak single top quark production was also measured and the results are consistent with theoretical predictions at the various energies.

  16. Search for quirks at the Fermilab Tevatron Collider

    Energy Technology Data Exchange (ETDEWEB)

    Abazov, V.M.; /Dubna, JINR; Abbott, B.; /Oklahoma U.; Abolins, M.; /Michigan State U.; Acharya, B.S.; /Tata Inst.; Adams, M.; /Illinois U., Chicago; Adams, T.; /Florida State U.; Alexeev, G.D.; /Dubna, JINR; Alkhazov, G.; /St. Petersburg, INP; Alton, A.; /Augustana Coll., Sioux Falls /Michigan U.; Alverson, G.; /Northeastern U.; Alves, G.A.; /Rio de Janeiro, CBPF /NIKHEF, Amsterdam

    2010-08-01

    We report results of a search for particles with anomalously high ionization in events with a high transverse energy jet and large missing transverse energy in 2.4 fb{sup -1} of integrated luminosity collected by the D0 experiment at the Fermilab Tevatron p{bar p} collider. Production of such particles (quirks) is expected in scenarios with extra QCD-like SU(N) sectors, and this study is the first dedicated search for such signatures. We find no evidence of a signal and set a lower mass limit of 107 GeV for the mass of a charged quirk with strong dynamics scale {Lambda} in the range from 10 keV to 1 MeV.

  17. New Measurements of Upsilon Spin Alignment at the Tevatron

    Directory of Open Access Journals (Sweden)

    Jones Matthew

    2012-06-01

    Full Text Available We describe a new analysis of γ(nS → μ+μ− decays collected in pp¯ $par p$ collisions with the CDF II detector at the Fermilab Tevatron. This analysis measures the angular distributions of the final state muons in the γ rest frame, providing new information about γ production polarization. We find the angular distributions to be nearly isotropic up to γ pT of 40 GeV/c, consistent with previous measurements by CDF, but inconsistent with results obtained by the D0 experiment. The results are compared with recent NLO calculations based on color-singlet matrix elements and non-relativistic QCD with color-octet matrix elements.

  18. New results on the b^-+c meson at the Tevatron

    Energy Technology Data Exchange (ETDEWEB)

    Rahaman, M.A.; /Pittsburgh U.

    2006-09-01

    The authors present recent results on B{sub c}{sup -} meson from the Tevatron. The B{sub c}{sup -} meson has been observed in semileptonic decays, B{sub c}{sup -} {yields} J/{psi}{ell}{sup -} {nu}X, both by CDF and D0 experiments at a significance larger than 5{sigma}. The D0 experiment has used the candidates in B{sub c}{sup -} {yields} J/{psi}{mu}{sup -} {nu}X decay to extract the mass and lifetime of B{sub c}{sup -} meson. The CDF experiment has used both electron and muon channel candidates in B{sub c}{sup -} {yields} J/{psi}{ell}{sup -} {nu}X decays to measure the relative production times branching ratio with respect to B{sup -} {yields} J/{psi}K{sup -} decay and also measured the lifetime of B{sub c}{sup -} meson in electron channel as {tau}(B{sub c}{sup -}) = 0.463{sub -0.055}{sup +0.073} {+-} 0.036 ps. The CDF experiment has also observed B{sub c}{sup -} {yields} J/{psi}{pi}{sup -} decay with a significance exceeding 6.5{sigma} and has measured the mass of B{sub c}{sup -} meson as M(B{sub c}{sup -}) = 6276.5 {+-} 4.0 {+-} 2.7 MeV/c{sup 2}.

  19. REFRACTIVE NEUTRON LENS

    OpenAIRE

    Petrov, P. V.; Kolchevsky, N. N.

    2013-01-01

    Compound concave refractive lenses are used for focusing neutron beam. Investigations of spectral and focusing properties of a refractive neutron lens are presented. Resolution of the imaging system on the base of refractive neutron lenses depends on material properties and parameters of neutron source. Model of refractive neutron lens are proposed. Results of calculation diffraction resolution and focal depth of refractive neutron lens are discussed.

  20. Contact lens in keratoconus

    OpenAIRE

    Rathi, Varsha M; Mandathara, Preeji S; Dumpati, Srikanth

    2013-01-01

    Contact lenses are required for the visual improvement in patients with keratoconus. Various contact lens options, such as rigid gas permeable (RGP) lenses, soft and soft toric lenses, piggy back contact lenses (PBCL), hybrid lenses and scleral lenses are availble. This article discusses about selection of a lens depending on the type of keratoconus and the fitting philosophies of various contact lenses including the starting trial lens. A Medline search was carried out for articles in the En...

  1. Measurement of the top quark properties at the Tevatron and the LHC

    CERN Document Server

    INSPIRE-00040958

    2014-01-01

    Almost two decades after its discovery at Fermilab's Tevatron collider experiments, the top quark is still under the spotlight due to its connections to some of the most interesting puzzles in the Standard Model. The Tevatron has been shut down two years ago, yet some interesting results are coming out of the CDF and D0 collaborations. The LHC collider at CERN produced two orders of magnitude more top quarks than Tevatron's, thus giving birth to a new era for top quark physics. While the LHC is also down at the time of this writing, many top quark physics results are being extracted out of the 7\\,TeV and 8\\,TeV proton proton collisions by the ATLAS and CMS collaborations, and many more are expected to appear before the LHC will be turned on again sometime in 2015. These proceedings cover a selection of recent results produced by the Tevatron and LHC experiments.

  2. Upgrading the Tevatron to a 1 TeV on 1 TeV pp collider

    International Nuclear Information System (INIS)

    Teng, L.C.

    1987-01-01

    This report describes the tasks necessary to change the Tevatron into a proton-proton collider. Also included in the discussion is an estimate of the cost to carry out the modification. 4 figs., 3 tabs

  3. Electroweak Physics at the Tevatron and LHC: Theoretical Status and Perspectives

    OpenAIRE

    Baur, U.

    2005-01-01

    I review the status of theoretical calculations relevant for electroweak physics at the Tevatron and LHC and discuss future directions. I also give a brief overview of current electroweak data and discuss future expectations.

  4. Measurements of Field Decay and Snapback Effect on Tevatron Dipole and Quadrupole Magnets

    CERN Document Server

    Velev, Gueorgui; Annala, Gerald; Bauer, Pierre; Carcagno, Ruben H; Di Marco, Joseph; Glass, Henry; Hanft, Ray; Kephart, Robert; Lamm, Michael J; Martens, Michael A; Schlabach, Philip; Sylvester, C D; Tartaglia, M; Tompkins, John

    2005-01-01

    Since the beginning of 2002 an intensive measurement program has been performed at the Fermilab Magnet Test Facility to understand dynamic effects in the Tevatron magnets. Based on the results of this program a new correction algorithm was proposed to compensate for the decay of the sextupole field during the dwell at injection and for the subsequent field "snapback" during the first few seconds of the energy ramp. Beam studies showed that the new correction algorithm works better than the original one, and improves the Tevatron efficiency by at least 3%. The beam studies also indicated insufficient correction during the first 20 s of the injection plateau where an unexpected discrepancy of 0.15 sextupole units of extra drift was observed. This paper reports on the most recent measurements of the Tevatron dipoles field at the beginning of the injection plateau. Results on the field decay and snapback in the Tevatron quadrupoles are also presented.

  5. Feasibility study of beam-beam compensation in the Tevatron with wires

    International Nuclear Information System (INIS)

    Sen, Tanaji; Erdelyi, Bela

    2005-01-01

    We explore the possibility of compensating long-range beam-beam interactions in the Tevatron by current carrying wires. Compensation strategies depend on whether the compensation is done close to the interaction or nonlocally, on the aspect ratio of the strong beam and on other details. Strategies for each case have been developed and applied to the Tevatron. We discuss the results of these strategies at injection and collision energy

  6. New particle signals at the SSC and at an upgraded Tevatron collider

    Energy Technology Data Exchange (ETDEWEB)

    Barnett, R.M.; Hollebeek, R.J.; White, A.P.; Yoh, J.; Baer, H.A.; Barnett, B.A.; Eichten, E.; Freeman, J.E.; Gamberini, G.; Grifols, J.A.

    1988-01-01

    We have studied the production and detection of several types of new particles at the Superconducting Super Collider (SSC) and at three possible upgrades of the Fermilab Tevatron Collider. We compare the physics potential of the SSC with that of an upgraded collider, and we discuss in depth the relative capabilities of the three Tevatron Collider upgrades. From a physics standpoint, we suggest that one of the proposed upgrades has several advantages. 34 refs., 21 figs., 5 tabs.

  7. Properties of the cathode lens combined with a focusing magnetic/immersion-magnetic lens

    Czech Academy of Sciences Publication Activity Database

    Konvalina, Ivo; Müllerová, Ilona

    2011-01-01

    Roč. 645, č. 1 (2011), s. 55-59 ISSN 0168-9002 R&D Projects: GA ČR GAP102/10/1410; GA AV ČR IAA100650902; GA MŠk ED0017/01/01 Institutional research plan: CEZ:AV0Z20650511 Keywords : cathode lens * compound objective lens * aberration coefficients * spot size * field calculations Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 1.207, year: 2011

  8. Electrostatic plasma lens for focusing negatively charged particle beams.

    Science.gov (United States)

    Goncharov, A A; Dobrovolskiy, A M; Dunets, S M; Litovko, I V; Gushenets, V I; Oks, E M

    2012-02-01

    We describe the current status of ongoing research and development of the electrostatic plasma lens for focusing and manipulating intense negatively charged particle beams, electrons, and negative ions. The physical principle of this kind of plasma lens is based on magnetic isolation electrons providing creation of a dynamical positive space charge cloud in shortly restricted volume propagating beam. Here, the new results of experimental investigations and computer simulations of wide-aperture, intense electron beam focusing by plasma lens with positive space charge cloud produced due to the cylindrical anode layer accelerator creating a positive ion stream towards an axis system is presented.

  9. Applications of electron lenses: scraping of high-power beams, beam-beam compensation, and nonlinear optics

    Energy Technology Data Exchange (ETDEWEB)

    Stancari, Giulio

    2014-09-11

    Electron lenses are pulsed, magnetically confined electron beams whose current-density profile is shaped to obtain the desired effect on the circulating beam. Electron lenses were used in the Fermilab Tevatron collider for bunch-by-bunch compensation of long-range beam-beam tune shifts, for removal of uncaptured particles in the abort gap, for preliminary experiments on head-on beam-beam compensation, and for the demonstration of halo scraping with hollow electron beams. Electron lenses for beam-beam compensation are being commissioned in the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory (BNL). Hollow electron beam collimation and halo control were studied as an option to complement the collimation system for the upgrades of the Large Hadron Collider (LHC) at CERN; a conceptual design was recently completed. Because of their electric charge and the absence of materials close to the proton beam, electron lenses may also provide an alternative to wires for long-range beam-beam compensation in LHC luminosity upgrade scenarios with small crossing angles. At Fermilab, we are planning to install an electron lens in the Integrable Optics Test Accelerator (IOTA, a 40-m ring for 150-MeV electrons) as one of the proof-of-principle implementations of nonlinear integrable optics to achieve large tune spreads and more stable beams without loss of dynamic aperture.

  10. Top quark mass measurement in the dilepton channel in the D0 experiment at the Tevatron

    International Nuclear Information System (INIS)

    Croc de Suray, A.

    2011-06-01

    The top quark is the heaviest standard model quark. Discovered in 1995 by the two Tevatron experiments it has atypical properties. In particular its time life is so short that it decays before hadronizing, so the top quark mass could be measured with a high precision. Data collected by the D0 experiment between 2002 and 2009, which represent an integrated luminosity of 5.4 fb -1 , are used to measure the top quark mass by using the matrix element method in the three dilepton channels: dielectron, electron-muon and dimuon. The measured mass, (174,0 ± 1,8 (stat.) ± 2,4 (syst.)) GeV, is in a good agreement with other measurements and limited by the systematic uncertainties for the first time in these channels. In this thesis different approaches have been studied to improve the accuracy of this measurement: the use of b-quark jet identification in order to optimize the selection of top - anti-top events and a better determination of the main systematic uncertainties. A special attention has been paid to the Monte-Carlo simulation of muons in D0: the improved smearing procedure for the simulated muons, discussed in this thesis, will be used to increase the accuracy of the top properties measurements as well as the precision of many other D0 measurements. (author)

  11. B Physics at tevatron and the B Factories

    International Nuclear Information System (INIS)

    Paus, C.

    2004-01-01

    The following contribution is in no way a complete summary of the physics of b hadrons but merely a selection of some key topics which the author considered exemplary to explain the essence of B physics to beginners in the field. The main emphasis has been put on electroweak decays of b hadrons which in one form or another contain information about the Cabibbo-Kobayashi-Maskawa matrix. The elements of this matrix define the coupling strength of the various quark pairs to the W boson. The coupling strengths cannot be predicted but have to be measured and are thus input parameters to the Standard Model of Particle Physics. Furthermore the CKM matrix is the mechanism which implements CP violation in the Standard Model. The phenomenon of CP violation and the CKM matrix are enjoying quite some attention since there are indications that something is not right in the Standard Model. This contribution discusses the most prominent measurements in the field of B physics which are presently performed or prepared at the Tevatron and the B factories. The experimental setup in terms of the accelerators and the experiments is described in the beginning. The differences between e+e- and pp machines and the corresponding detector designs are discussed in detail. In the next step the analysis tools are developed step by step by describing the measurements which make use of them. (Author) 39 refs

  12. Measurements of top-quark properties at the Tevatron

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Andreas Werner [Fermilab

    2013-07-30

    Recent measurements of top-quark properties at the Tevatron are presented. CDF uses data corresponding up to 9.0 fb-1 to measure the ratio R of the branching fractions , the branching fraction for top-quarks decaying into τ leptons and the cross section for the production of an additional γ in t production. The results from all these measurements agree well with their respective Standard Model expectation. DØ uses 5.3 fb-1 of data to measure the t cross section as a function of the time. A time dependency would imply Lorentz invariance violation as implemented by the Standard Model extension. No time dependency is observed and DØ sets first limits in the top-quark sector for Lorentz invariance violation. DØ also determines indirectly the top quark width using the results of earlier measurements at DØ. The measured top quark width is in agreement with the SM expectation and does not show any hints for new physics contributions.

  13. The search for the Higgs at the Tevatron

    International Nuclear Information System (INIS)

    Lucotte, A.

    2004-01-01

    The Tevatron has undergone an impressive technical renovation program whose final aim is to reach an integrated luminosity of 15 fb -1 per experiment. Both CDF and DO detectors have been upgraded in the fields of detection, triggering, track reconstruction and particle identification. In the framework of the standard model, theoretical studies show that for a luminosity of only 2 fb -1 (that is the first step of the renovation program) CDF and DO could barely extend the domain already excluded by LEP for the existence of the Higgs boson. On the other hand for a luminosity of 15 fb -1 , a standard Higgs boson could be excluded up to 180 GeV/c 2 and discovered up to 125 GeV/c 2 . Moreover, a 3*σ result could be obtained in the decay channels H → bb-bar and H → W + W - up to 180 GeV/c 2 . In the framework of the minimal supersymmetric standard model (MSSM), at least 20 fb -1 are required for the discovery of the Higgs boson in the energy range: 80 ≤ m A ≤ 380 GeV/c 2 . (A.C.)

  14. Searching for a light top squark at the Fermilab Tevatron

    International Nuclear Information System (INIS)

    Mahlon, G.; Kane, G.L.

    1997-01-01

    We describe a method to help the search for a light top squark (M t +M LSP t ) at the Fermilab Tevatron. Traditional search methods rely upon a series of stringent background-reducing cuts which, unfortunately, leave very few signal events given the present data set. To avoid this difficulty, we instead suggest using a milder set of cuts, combined with a open-quotes superweight,close-quote close-quote whose purpose is to discriminate between signal and background events. The superweight consists of a sum of terms, each of which are either zero or one. The terms are assigned event-by-event depending upon the values of various observables. We suggest a method for choosing the observables as well as the criteria used to assign the values such that the superweight is open-quotes large close-quote close-quote for the supersymmetric signal and open-quotes small close-quote close-quote for the standard model background. For illustration, we mainly consider the detection of tops squarks coming from top quark decay, making our analysis especially relevant to the W+2 jets top quark sample. copyright 1997 The American Physical Society

  15. An Examination of the Effects of Electronic Word of Mouth on Consumers’ Purchase Decision: Through the Lens of Experience Good and Search Good

    OpenAIRE

    Zhao, Zichen

    2013-01-01

    The prevailing of the Internet facilitates consumers to share information, opinions and experiences of products and services online. This new form of word of mouth communication is called electronic word of mouth (WOM). Nowadays, electronic word of mouth plays an important role in the consumers’ information search during the decision making process. A large number of managerial and academic attentions have been drawn to the effects of electronic WOM on consumer’s purchase decision. Factors wh...

  16. Role of Aquaporin 0 in lens biomechanics

    Energy Technology Data Exchange (ETDEWEB)

    Sindhu Kumari, S.; Gupta, Neha [Physiology and Biophysics, Stony Brook University, Stony Brook, NY (United States); Shiels, Alan [Washington University School of Medicine, St. Louis, MO (United States); FitzGerald, Paul G. [Cell Biology and Human Anatomy, School of Medicine, University of California, Davis, CA (United States); Menon, Anil G. [University of Cincinnati College of Medicine, Cincinnati, OH (United States); Mathias, Richard T. [Physiology and Biophysics, Stony Brook University, Stony Brook, NY (United States); SUNY Eye Institute, NY (United States); Varadaraj, Kulandaiappan, E-mail: kulandaiappan.varadaraj@stonybrook.edu [Physiology and Biophysics, Stony Brook University, Stony Brook, NY (United States); SUNY Eye Institute, NY (United States)

    2015-07-10

    Maintenance of proper biomechanics of the eye lens is important for its structural integrity and for the process of accommodation to focus near and far objects. Several studies have shown that specialized cytoskeletal systems such as the beaded filament (BF) and spectrin-actin networks contribute to mammalian lens biomechanics; mutations or deletion in these proteins alters lens biomechanics. Aquaporin 0 (AQP0), which constitutes ∼45% of the total membrane proteins of lens fiber cells, has been shown to function as a water channel and a structural cell-to-cell adhesion (CTCA) protein. Our recent ex vivo study on AQP0 knockout (AQP0 KO) mouse lenses showed the CTCA function of AQP0 could be crucial for establishing the refractive index gradient. However, biomechanical studies on the role of AQP0 are lacking. The present investigation used wild type (WT), AQP5 KO (AQP5{sup −/−}), AQP0 KO (heterozygous KO: AQP0{sup +/−}; homozygous KO: AQP0{sup −/−}; all in C57BL/6J) and WT-FVB/N mouse lenses to learn more about the role of fiber cell AQPs in lens biomechanics. Electron microscopic images exhibited decreases in lens fiber cell compaction and increases in extracellular space due to deletion of even one allele of AQP0. Biomechanical assay revealed that loss of one or both alleles of AQP0 caused a significant reduction in the compressive load-bearing capacity of the lenses compared to WT lenses. Conversely, loss of AQP5 did not alter the lens load-bearing ability. Compressive load-bearing at the suture area of AQP0{sup +/−} lenses showed easy separation while WT lens suture remained intact. These data from KO mouse lenses in conjunction with previous studies on lens-specific BF proteins (CP49 and filensin) suggest that AQP0 and BF proteins could act co-operatively in establishing normal lens biomechanics. We hypothesize that AQP0, with its prolific expression at the fiber cell membrane, could provide anchorage for cytoskeletal structures like BFs and

  17. Experimental and Numerical Studies on the Proposed Application of Hollow Electron Beam Collimation for the LHC at CERN

    Energy Technology Data Exchange (ETDEWEB)

    Moens, Vince [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)

    2013-01-01

    electron beam and initiates 3D simulations in order to determine the effect of the HEBL on the beam core. Experiments were conducted in the Tevatron Electron Lens Test Stand (TELTS) at Fermi National Accelerator Lab (Fermilab) (USA) in the lower Linear Accelerator (LINAC) gallery.

  18. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... One Use Facts About Colored Contacts and Halloween Safety Colored Contact Lens Facts Over-the-Counter Costume ... new application of artificial intelligence shows whether a patient’s eyes point to high blood pressure or risk ...

  19. Colored Contact Lens Dangers

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  20. Colored Contact Lens Dangers

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    Full Text Available ... had not been properly fitted by an eye care professional, the lenses stuck to my eye like ... lenses do not require the same level of care or consideration as a standard contact lens because ...

  1. Colored Contact Lens Dangers

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    Full Text Available ... sell contacts without a prescription are breaking the law, and may be fined $11,000 per violation. " ... wear any kind of contact lens. In Butler's case, the lenses caused an infection and left her ...

  2. Colored Contact Lens Dangers

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    Full Text Available ... One Use Facts About Colored Contacts and Halloween Safety Colored Contact Lens Facts Over-the-Counter Costume ... Costume Contact Lenses Can Ruin Vision Eye Makeup Safety In fact, it is illegal to sell colored ...

  3. Colored Contact Lens Dangers

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  4. Colored Contact Lens Dangers

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    Full Text Available ... One Use Facts About Colored Contacts and Halloween Safety Colored Contact Lens Facts Over-the-Counter Costume ... Academy Jobs at the Academy Financial Relationships with Industry Medical Disclaimer Privacy Policy Terms of Service For ...

  5. Colored Contact Lens Dangers

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  6. Colored Contact Lens Dangers

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    Full Text Available ... One Use Facts About Colored Contacts and Halloween Safety Colored Contact Lens Facts Over-the-Counter Costume ... use of colored contact lenses , from the U.S. Food and Drug Administration (FDA). Are the colored lenses ...

  7. Colored Contact Lens Dangers

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    Full Text Available ... an impulsive buy from a souvenir shop, but 10 hours after she first put in a pair ... Prescription Contact Lens Laura: Vision Loss After Just 10 Hours Robyn: Blurry Vision and Daily Eye Drops ...

  8. Colored Contact Lens Dangers

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    Full Text Available ... Contact Lens Facts Over-the-Counter Costume Contacts May Contain Chemicals Harmful to Eyes Four Ways Over- ... without a prescription are breaking the law, and may be fined $11,000 per violation. "Many of ...

  9. Colored Contact Lens Dangers

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  10. Colored Contact Lens Dangers

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    Full Text Available ... One Use Facts About Colored Contacts and Halloween Safety Colored Contact Lens Facts Over-the-Counter Costume ... an ophthalmologist — an eye medical doctor — who will measure each eye and talk to you about proper ...

  11. Colored Contact Lens Dangers

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    Full Text Available ... prescription. Follow the contact lens care directions for cleaning, disinfecting, and wearing the lenses. Never share contact ... with Industry Medical Disclaimer Privacy Policy Terms of Service For Advertisers For Media Ophthalmology Job Center © American ...

  12. Observation of Central Exclusive Diphoton Production at the Tevatron

    Energy Technology Data Exchange (ETDEWEB)

    Brucken, Jens Erik [Univ. of Helsinki (Finland); Helsinki Inst. of Physics (Finland)

    2013-01-01

    We have observed exclusive γγ production in proton-antiproton collisions at the Tevatron at √ s = 1.96 TeV. We use data corresponding to 1.11 ± 0.07 fb-1 integrated luminosity taken by the Run II Collider Detector at Fermilab, with a trigger requiring two electromagnetic showers, each with transverse energy ET > 2 GeV, and vetoing on hits in the forward beam shower counters. We select events with two electromagnetic showers, each with transverse energy ET > 2.5 GeV and pseudorapidity |η| < 1.0, with no other particles detected in -7.4 < η < +7.4. The two showers have similar ET and an azimuthal angle separation Δφ ~ π; we find 34 events with exactly two matching charged particle tracks, agreeing with expectations for the QED process p¯p → p+e+e- + ¯p by two photon exchange; and we find 43 events with no tracks. The latter are candidates for the exclusive process p¯p → p + γγ + ¯p by double pomeron exchange. We use the strip and wire chambers at the longitudinal shower maximum position within the calorimeter to measure a possible exclusive background from IP + IP → π0π0, and conclude that it is consistent with zero and is < 15 events at 95% C.L. The measured cross section is σγγ,excl(|η| < 1, ET (γ) > 2.5 GeV) = 2.48 +0.40 -0.35(stat) +0.40 -0.51(syst) pb and in agreement with the theoretical predictions. This process is closely related to exclusive Higgs boson production pp → p + H + p at the Large Hadron Collider. The observation of the exclusive production of diphotons shows that exclusive Higgs production can happen and could be observed with a proper experimental setup.

  13. Search for the single top quarks produced in s-channel via electroweak interactions at √s = 1.96 at the Tevatron

    Energy Technology Data Exchange (ETDEWEB)

    Jabeen, Shabnam [Univ. of Kansas, Lawrence, KS (United States)

    2006-01-01

    The authors present a search for single top quarks produced in the s-channel electroweak production mode. The search is performed in the electron+jets decay channels, with one or more secondary-vertex tagged jets to indicate the presence of a b-jet and hence improving the signal:background ratio. Separation between signal and background is further enhanced by the use of Feed Forward Neural networks. 360 pb-1 of Run II data used for this analysis was delivered by the Tevatron, and collected by D0 between August 2002 and August 2004. The resulting 95% confidence level upper limit is 4 pb.

  14. Viscous froth lens

    Science.gov (United States)

    Green, T. E.; Bramley, A.; Lue, L.; Grassia, P.

    2006-11-01

    Microscale models of foam structure traditionally incorporate a balance between bubble pressures and surface tension forces associated with curvature of bubble films. In particular, models for flowing foam microrheology have assumed this balance is maintained under the action of some externally imposed motion. Recently, however, a dynamic model for foam structure has been proposed, the viscous froth model, which balances the net effect of bubble pressures and surface tension to viscous dissipation forces: this permits the description of fast-flowing foam. This contribution examines the behavior of the viscous froth model when applied to a paradigm problem with a particularly simple geometry: namely, a two-dimensional bubble “lens.” The lens consists of a channel partly filled by a bubble (known as the “lens bubble”) which contacts one channel wall. An additional film (known as the “spanning film”) connects to this bubble spanning the distance from the opposite channel wall. This simple structure can be set in motion and deformed out of equilibrium by applying a pressure across the spanning film: a rich dynamical behavior results. Solutions for the lens structure steadily propagating along the channel can be computed by the viscous froth model. Perturbation solutions are obtained in the limit of a lens structure with weak applied pressures, while numerical solutions are available for higher pressures. These steadily propagating solutions suggest that small lenses move faster than large ones, while both small and large lens bubbles are quite resistant to deformation, at least for weak applied back pressures. As the applied back pressure grows, the structure with the small lens bubble remains relatively stiff, while that with the large lens bubble becomes much more compliant. However, with even further increases in the applied back pressure, a critical pressure appears to exist for which the steady-state structure loses stability and unsteady

  15. Prospects for 6 to 10 tesla magnets for a TEVATRON upgrade

    International Nuclear Information System (INIS)

    Mantsch, Paul M.

    1988-01-01

    The first SSC physics is at least 10 years away. An upgrade of the Fermilab Tevatron will ensure the continuity of a vigorous high-energy physics program until the SSC turns on. Three basic proposals are under consideration: /bar p/p at 3 /times/ 10 31 --Increase luminosity by improvements to the p source. pp at 1 TeV and 2 /times/ 10 32 --Move the main ring to a new tunnel, build a second Tevatron ring, and /bar p/p > 1.5 TeV and 7 /times/ 10 30 --Replace the tevatron with a higher energy ring. The last two options requires about a hundred 6.6-tesla dipoles in addition to a ring of Tevatron strength (4.4 T) magnets. These higher-field magnets are necessary in both rings to lengthen the straight sections in order to realize the collision optics. The third option requires a ring of magnets of 6.6 T or slightly higher to replace the present Tevatron plus a number of special 8--9 tesla magnets. The viability of the high-energy option then depends on the practicality of sizable numbers of reliable 8--9 tesla dipoles as well as 800 6.6-tesla dipoles. The following develops a specification for an 8.8 T dipole, examines the design considerations and reviews the current state of high-field magnet development. 22 figs., 3 tabs

  16. 2007 2008 ACADEMIC TRAINING PROGRAMME: Tevatron: The Cinderella Story or The Art Of Collider Commissioning

    CERN Multimedia

    2007-01-01

    LECTURE SERIES 01, 03, 04, 05 October 2007 Main Auditorium, bldg. 500 Tevatron: The Cinderella Story or The Art Of Collider Commissioning V. SHILTSEV / Fermi National Accelerator Laboraty, Batavia IL, USA The Tevatron Collider at Fermilab (Batavia, IL, USA) is the world’s highest energy particle collider at 1.8TeV c.m.e. The machine was a centerpiece of the US and world’s High Energy Physics for many years. Currently, the Tevatron is in the last years of its operation in so-called Run II which started 2001 and is tentatively scheduled to end in 2010. In this lecture series, we’ll try to learn from the exciting story of the Tevatron Collider Run II: the story of long preparations, great expectations, initial difficulties, years of "blood and sweat", continuous upgrades, exceeding its goals, high emotions, tune-up of accelerator organization for "combat fighting". The lectures will cover Introduction to the Tevatron, its history and Run II; "Plumbing"...

  17. The upgraded data acquisition system for beam loss monitoring at the Fermilab Tevatron and Main Injector

    International Nuclear Information System (INIS)

    Baumbaugh, A.; Briegel, C.; Brown, B.C.; Capista, D.; Drennan, C.; Fellenz, B.; Knickerbocker, K.; Lewis, J.D.; Marchionni, A.; Needles, C.; Olson, M.

    2011-01-01

    A VME-based data acquisition system for beam-loss monitors has been developed and is in use in the Tevatron and Main Injector accelerators at the Fermilab complex. The need for enhanced beam-loss protection when the Tevatron is operating in collider-mode was the main driving force for the new design. Prior to the implementation of the present system, the beam-loss monitor system was disabled during collider operation and protection of the Tevatron magnets relied on the quench protection system. The new Beam-Loss Monitor system allows appropriate abort logic and thresholds to be set over the full set of collider operating conditions. The system also records a history of beam-loss data prior to a beam-abort event for post-abort analysis. Installation of the Main Injector system occurred in the fall of 2006 and the Tevatron system in the summer of 2007. Both systems were fully operation by the summer of 2008. In this paper we report on the overall system design, provide a description of its normal operation, and show a number of examples of its use in both the Main Injector and Tevatron.

  18. Ultrastructural effects of silicone oil on the clear crystalline lens of the human eye.

    Science.gov (United States)

    Soliman, Wael; Sharaf, Mohamed; Abdelazeem, Khaled; El-Gamal, Dalia; Nafady, Allam

    2018-03-01

    To evaluate light and electron microscopic changes of the anterior capsule and its epithelium after clear lens extraction of vitrectomized myopic eyes with silicone oil tamponade. This prospective, controlled, non-randomized, interventional study included 20 anterior lens capsular specimens that were excised during combined clear lens extraction and silicone oil removal from previously vitrectomized highly myopic patients with silicone oil tamponade for previous retinal detachment surgeries. The specimens were examined via light microscopy and electron microscopy and compared with 20 anterior capsule specimens removed during clear lens extraction of non-vitrectomized highly myopic eyes. Light microscopic examination of clear lens anterior capsule specimens of vitrectomized myopic eyes filled with silicone oil showed relatively more flat cells with irregular outline of lens' epithelial cells with wide intercellular spaces, deeply stained nuclei, and multiple intracytoplasmic vacuoles. Scanning electron microscopy revealed collagenous surfaces filled with multiple pits, depressions, and abnormal deposits. Transmission electron microscopy revealed lens epithelial cells with apoptotic changes, many cytoplasmic vacuoles, and filopodia-like protrusions between lens epithelial cells and the capsule. Epithelial proliferation and multilayering were also observed. silicone oil may play a role in the development of apoptotic and histopathological changes in clear lens epithelial cells. Clarity of the lens at the time of silicone oil removal does not indicate an absence of cataractous changes. We found justification of combined clear lens extraction and silicone oil removal or combined phacovitrectomy when silicone oil injection is planned, but further long-term studies with larger patient groups are required.

  19. CERN scientists take part in the Tevatron Run II performance review committee

    CERN Multimedia

    Maximilien Brice

    2002-01-01

    Tevatron Run II is under way at Fermilab, exploring the high-energy frontier with upgraded detectors that will address some of the biggest questions in particle physics.Until CERN's LHC switches on, the Tevatron proton-antiproton collider is the world's only source of top quarks. It is the only place where we can search for supersymmetry, for the Higgs boson, and for signatures of additional dimensions of space-time. The US Department of Energy (DOE) recently convened a high-level international review committee to examine Fermilab experts' first-phase plans for the accelerator complex. Pictured here with a dipole magnet in CERN's LHC magnet test facility are the four CERN scientists who took part in the DOE's Tevatron review. Left to right: Francesco Ruggiero, Massimo Placidi, Flemming Pedersen, and Karlheinz Schindl. Further information: CERN Courier 43 (1)

  20. TESS Lens-Bezel Assembly Modal Testing

    Science.gov (United States)

    Dilworth, Brandon J.; Karlicek, Alexandra

    2017-01-01

    The Transiting Exoplanet Survey Satellite (TESS) program, led by the Kavli Institute for Astrophysics and Space Research at the Massachusetts Institute of Technology (MIT) will be the first-ever spaceborne all-sky transit survey. MIT Lincoln Laboratory is responsible for the cameras, including the lens assemblies, detector assemblies, lens hoods, and camera mounts. TESS is scheduled to be launched in August of 2017 with the primary goal to detect small planets with bright host starts in the solar neighborhood, so that detailed characterizations of the planets and their atmospheres can be performed. The TESS payload consists of four identical cameras and a data handling unit. Each camera consists of a lens assembly with seven optical elements and a detector assembly with four charge-coupled devices (CCDs) including their associated electronics. The optical prescription requires that several of the lenses are in close proximity to a neighboring element. A finite element model (FEM) was developed to estimate the relative deflections between each lens-bezel assembly under launch loads to predict that there are adequate clearances preventing the lenses from making contact. Modal tests using non-contact response measurements were conducted to experimentally estimate the modal parameters of the lens-bezel assembly, and used to validate the initial FEM assumptions. Key Words Non-contact measurements, modal analysis, model validation

  1. Measuring the top anti-t Production Cross-Section in the Electron + Jets Channel in Proton - Anti-proton Collisions at s**(1/2) = 1.96-TeV with the D0 Detector at the Tevatron: A Monte Carlo Study

    Energy Technology Data Exchange (ETDEWEB)

    Park, Su-Jung; /Bonn U.

    2004-02-01

    The measurement of the t{bar t} production cross section at {radical}s = 1.96 TeV using the final state with an electron and jets is studied with Monte Carlo event samples. All methods used in the real data analysis to measure efficiencies and to estimate the background contributions are examined. The studies focus on measuring the electron reconstruction efficiencies as well as on improving the electron identification and background suppression. With a generated input cross section of 7 pb the following result is obtained: {sigma}{sub t{bar t}} = (7 {+-} 1.63(stat){sub -1.14}{sup +0.94} (syst)) pb.

  2. A magnetic-lens - mini-orange coincidence spectrometer

    International Nuclear Information System (INIS)

    Bargholtz, C.; Holmberg, L.; Ruus, N.; Tegner, P.E.; Weiss, G.

    1997-04-01

    A coincidence spectrometer consisting of a Gerholm type magnetic lens and a permanent magnet mini-orange spectrometer is described. Electron-electron or electron-positron coincidences may be registered in various angular settings. The spectrometer has been developed mainly to search for anomalous contributions to Bhabha scattering or positrons and is at present used for such studies. 6 refs

  3. A catoptric lens

    International Nuclear Information System (INIS)

    Rambauske, W.R.

    1973-01-01

    The invention relates to a catoptric lens for combining energies transmitted by several sources such as lasers; said lens comprising mirrors, the reflective surfaces of which have their focuses spaced from a common axis of symmetry. By means of these reflecting surfaces, which are generated by the nutation of portions of quadratic conics about the axis of symmetry, it is possible to focus the energy emmited by several lasers at the focus of the exit-mirror reflecting surface. This can be applied to thermonuclear fusion [fr

  4. Direct photon production in NCG QCD at the tevatron and LHC

    Energy Technology Data Exchange (ETDEWEB)

    Bekli, M. R.; Mebarki, N.; Chadou, I. [Laboratoire de Physique Mathematique et Subatomique, Mentouri University, Constantine (Algeria)

    2012-06-27

    The minimal NCSM contribution of a direct photon production at the Tevatron and LHC is obtained and the phenomenological implications are discussed. Some behaviors are discussed. It is shown that the effect of the space-time noncommutativity becomes important at very high energies leading to a violation of unitarity.

  5. B_s oscillation and prospects for delta m_s at the Tevatron

    Energy Technology Data Exchange (ETDEWEB)

    Menzemer, Stephanie; /MIT

    2005-07-01

    Till the start of the LHC, the Tevatron is the only running accelerator which produces enough B{sub s} mesons to perform {Delta}m{sub s} measurements. The status--as it was at the time of the conference--of two different {Delta}m{sub s} analysis performed both by the CDF and D0 collaboration will be presented.

  6. Combination of measurements of the top-quark pair production cross section from the Tevatron Collider

    Czech Academy of Sciences Publication Activity Database

    Aaltonen, T.; Abazov, V. M.; Abbott, B.; Kupčo, Alexander; Lokajíček, Miloš; Lysák, Roman

    2014-01-01

    Roč. 89, č. 7 (2014), "072001-1"-"072001-16" ISSN 1550-7998 R&D Projects: GA MŠk(CZ) LG12006 Institutional support: RVO:68378271 Keywords : Batavia TEVATRON Coll * quantum chromodynamics * perturbation theory * statistical analysis * CDF * DZERO Subject RIV: BF - Elementary Particles and High Energy Physics Impact factor: 4.643, year: 2014

  7. Observation and studies of double J/psi production at the Tevatron

    Czech Academy of Sciences Publication Activity Database

    Abazov, V. M.; Abbott, B.; Acharya, B.S.; Kupčo, Alexander; Lokajíček, Miloš

    2014-01-01

    Roč. 90, č. 11 (2014), "111101-1"-"111101-8" ISSN 1550-7998 R&D Projects: GA MŠk(CZ) LG12006 Institutional support: RVO:68378271 Keywords : Batavia TEVATRON Coll * parton * density * nucleon * model * anti-p p * inclusive reaction Subject RIV: BF - Elementary Particles and High Energy Physics Impact factor: 4.643, year: 2014

  8. Recent results on QCD at the Tevatron (CDF and D0)

    International Nuclear Information System (INIS)

    Meschi, E.

    1993-11-01

    In the last run the Tevatron collider delivered an integrated luminosity of 29.9 pb -1 to CDF and D0. We describe here some preliminary result from analyses of relevant QCD processes in the 1992--1993 data from the two experiments

  9. BTEV: a dedicated B physics detector at the Fermilab Tevatron Collider

    International Nuclear Information System (INIS)

    Butler, J.N.

    1996-11-01

    The capabilities of future Dedicated Hadron Collider B Physics experiments are discussed and compared to experiments that will run in the next few years. The design for such an experiment at the Tevatron Collider is presented and an evolutionary path for developing it is outlined. 9 refs., 3 figs., 4 tabs

  10. Development of hollow electron beams for proton and ion collimation

    CERN Document Server

    Stancari, G.; Kuznetsov, G.; Shiltsev, V.; Still, D.A.; Valishev, A.; Vorobiev, L.G.; Assmann, R.; Kabantsev, A.

    2010-01-01

    Magnetically confined hollow electron beams for controlled halo removal in high-energy colliders such as the Tevatron or the LHC may extend traditional collimation systems beyond the intensity limits imposed by tolerable material damage. They may also improve collimation performance by suppressing loss spikes due to beam jitter and by increasing capture efficiency. A hollow electron gun was designed and built. Its performance and stability were measured at the Fermilab test stand. The gun will be installed in one of the existing Tevatron electron lenses for preliminary tests of the hollow-beam collimator concept, addressing critical issues such as alignment and instabilities of the overlapping proton and electron beams

  11. Development of hollow electron beams for proton and ion collimation

    CERN Document Server

    Stancari, G; Kuznetsov, G; Shiltsev, V; Still, D A; Valishev, A; Vorobiev, L G; Assmann, R; Kabantsev, A

    2012-01-01

    Magnetically confined hollow electron beams for controlled halo removal in high-energy colliders such as the Tevatron or the LHC may extend traditional collimation systems beyond the intensity limits imposed by tolerable material damage. They may also improve collimation performance by suppressing loss spikes due to beam jitter and by increasing capture efficiency. A hollow electron gun was designed and built. Its performance and stability were measured at the Fermilab test stand. The gun will be installed in one of the existing Tevatron electron lenses for preliminary tests of the hollow-beam collimator concept, addressing critical issues such as alignment and instabilities of the overlapping proton and electron beams.

  12. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... prescription. There is no such thing as a "one size fits all" contact lens. Lenses that are not properly fitted may scratch the eye or cause blood vessels to grow into the cornea. Even if you have perfect vision, you need to get an eye exam and a prescription ...

  13. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... Ophthalmologist Patient Stories Español Eye Health / News Halloween Hazard: The Hidden Dangers of Buying Decorative Contact Lenses ... One Use Facts About Colored Contacts and Halloween Safety Colored Contact Lens Facts Over-the-Counter Costume ...

  14. MISSING: BUBBLE CHAMBER LENS

    CERN Multimedia

    2001-01-01

    Would the person who borrowed the large bubble chamber lens from the Microcosm workshops on the ISR please return it. This is a much used piece from our object archives. If anybody has any information about the whereabouts of this object, please contact Emma.Sanders@cern.ch Thank you

  15. The Lens of Chemistry

    Science.gov (United States)

    Thalos, Mariam

    2013-01-01

    Chemistry possesses a distinctive theoretical lens--a distinctive set of theoretical concerns regarding the dynamics and transformations of a perplexing variety of organic and nonorganic substances--to which it must be faithful. Even if it is true that chemical facts bear a special (reductive) relationship to physical facts, nonetheless it will…

  16. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... wear any kind of contact lens. In Butler's case, the lenses caused an infection and left her with a corneal ... A recent article from U.S. News and World Report explains what ophthalmologists are and how they can ...

  17. Thermal Lens Microscope

    Science.gov (United States)

    Uchiyama, Kenji; Hibara, Akihide; Kimura, Hiroko; Sawada, Tsuguo; Kitamori, Takehiko

    2000-09-01

    We developed a novel laser microscope based on the thermal lens effect induced by a coaxial beam comprised of excitation and probe beams. The signal generation mechanism was confirmed to be an authentic thermal lens effect from the measurement of signal and phase dependences on optical configurations between the sample and the probe beam focus, and therefore, the thermal lens effect theory could be applied. Two-point spatial resolution was determined by the spot size of the excitation beam, not by the thermal diffusion length. Sensitivity was quite high, and the detection ability, evaluated using a submicron microparticle containing dye molecules, was 0.8 zmol/μm2, hence a distribution image of trace chemical species could be obtained quantitatively. In addition, analytes are not restricted to fluorescent species, therefore, the thermal lens microscope is a promising analytical microscope. A two-dimensional image of a histamine molecule distribution, which was produced in mast cells at the femtomole level in a human nasal mucous polyp, was obtained.

  18. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... an Ophthalmologist Patient Stories Español Eye Health / News Halloween Hazard: The Hidden Dangers of Buying Decorative Contact ... After One Use Facts About Colored Contacts and Halloween Safety Colored Contact Lens Facts Over-the-Counter ...

  19. Clinical survey of lens care in contact lens patients.

    Science.gov (United States)

    Ky, W; Scherick, K; Stenson, S

    1998-10-01

    Overall, contact lenses provide a safe and effective modality for vision correction. However, problems do occasionally arise. Up to 80% of contact lens complications can be traced to poor patient compliance with recommended lens care guidelines. We conducted a survey to evaluate the level of patient compliance in specific areas of lens care and maintenance and to assess patient knowledge of basic contact lens information. Patients were asked to complete an anonymous 15 question survey that focused on lens care--specifically the use of contact lens cleaners, methods of disinfection, enzyme treatments, use of rewetting drops, and the frequency of follow-up exams. In addition, the survey included six true/false questions relating to contact lens care and safety. There were a total of 103 participants in the study. Approximately 24% of patients stated they never cleaned their lenses prior to disinfection, and 5% used saline solutions as their primary mode of disinfection. A sizable portion of those surveyed (43% of soft lens wearers and 71% of rigid gas permeable lens wearers) either never used enzyme cleaners or used them less than once a month. Seventy percent of patients either never used rewetting drops or used them less than once a day. Twenty-nine percent of patients consulted their eye care professionals every 2 years and 6% less often than every two years. Six questions assessed patient knowledge of contact lens care safety. Of a possible six out of six correct answers, the mean number of correct responses was 3.74. A sizable proportion of contact lens wearers do not adequately adhere to recommended contact lens care, and many have an inadequate understanding of contact lens care guidelines. Therefore, it is important that practitioners place more emphasis on patient education at the time of initial contact lens fitting and reinforce such instruction during follow-up visits.

  20. Electron and photon identification in the D0 experiment

    Energy Technology Data Exchange (ETDEWEB)

    Abazov, V. M.; Abbott, B.; Acharya, B. S.; Adams, M.; Adams, T.; Agnew, J. P.; Alexeev, G. D.; Alkhazov, G.; Alton, A.; Askew, A.; Atkins, S.; Augsten, K.; Avila, C.; Badaud, F.; Bagby, L.; Baldin, B.; Bandurin, D. V.; Banerjee, S.; Barberis, E.; Baringer, P.; Bartlett, J. F.; Bassler, U.; Bazterra, V.; Bean, A.; Begalli, M.; Bellantoni, L.; Beri, S. B.; Bernardi, G.; Bernhard, R.; Bertram, I.; Besançon, M.; Beuselinck, R.; Bhat, P. C.; Bhatia, S.; Bhatnagar, V.; Blazey, G.; Blessing, S.; Bloom, K.; Boehnlein, A.; Boline, D.; Boos, E. E.; Borissov, G.; Borysova, M.; Brandt, A.; Brandt, O.; Brock, R.; Bross, A.; Brown, D.; Bu, X. B.; Buehler, M.; Buescher, V.; Bunichev, V.; Burdin, S.; Buszello, C. P.; Camacho-Pérez, E.; Casey, B. C. K.; Castilla-Valdez, H.; Caughron, S.; Chakrabarti, S.; Chan, K. M.; Chandra, A.; Chapon, E.; Chen, G.; Cho, S. W.; Choi, S.; Choudhary, B.; Cihangir, S.; Claes, D.; Clutter, J.; Cooke, M.; Cooper, W. E.; Corcoran, M.; Couderc, F.; Cousinou, M. -C.; Cutts, D.; Das, A.; Davies, G.; de Jong, S. J.; De La Cruz-Burelo, E.; Déliot, F.; Demina, R.; Denisov, D.; Denisov, S. P.; Desai, S.; Deterre, C.; DeVaughan, K.; Diehl, H. T.; Diesburg, M.; Ding, P. F.; Dominguez, A.; Dubey, A.; Dudko, L. V.; Duperrina, A.; Dutt, S.; Eads, M.; Edmunds, D.; Ellison, J.; Elvira, V. D.; Enari, Y.; Evans, H.; Evdokimov, V. N.; Feng, L.; Ferbel, T.; Fiedler, F.; Filthaut, F.; Fisher, W.; Fisk, H. E.; Fortner, M.; Fox, H.; Fuess, S.; Garbincius, P. H.; Garcia-Bellido, A.; García-González, J. A.; Gavrilov, V.; Geng, W.; Gerber, C. E.; Gershtein, Y.; Ginther, G.; Golovanov, G.; Grannis, P. D.; Greder, S.; Greenlee, H.; Grenier, G.; Gris, Ph.; Grivaz, J. -F.; Grohsjean, A.; Grünendahl, S.; Grünewald, M. W.; Guillemin, T.; Gutierrez, G.; Gutierrez, P.; Haley, J.; Han, L.; Harder, K.; Harel, A.; Hauptman, J. M.; Hays, J.; Head, T.; Hebbeker, T.; Hedin, D.; Hegab, H.; Heinson, A. P.; Heintz, U.; Hensel, C.; Heredia-De La Cruz, I.; Herner, K.; Hesketh, G.; Hildreth, M. D.; Hirosky, R.; Hoang, T.; Hobbs, J. D.; Hoeneisen, B.; Hogan, J.; Hohlfeld, M.; Holzbauer, J. L.; Howley, I.; Hubacek, Z.; Hynek, V.; Iashvili, I.; Ilchenko, Y.; Illingworth, R.; Ito, A. S.; Jabeen, S.; Jaffré, M.; Jayasinghe, A.; Jeong, M. S.; Jesik, R.; Jiang, P.; Johns, K.; Johnson, E.; Johnson, M.; Jonckheere, A.; Jonsson, P.; Joshi, J.; Jung, A. W.; Juste, A.; Kajfasz, E.; Karmanov, D.; Katsanos, I.; Kehoe, R.; Kermiche, S.; Khalatyan, N.; Khanov, A.; Kharchilava, A.; Kharzheev, Y. N.; Kiselevich, I.; Kohli, J. M.; Kozelov, A. V.; Kraus, J.; Kumar, A.; Kupco, A.; Kurča, T.; Kuzmin, V. A.; Lammers, S.; Lebrun, P.; Lee, H. S.; Lee, S. W.; Lee, W. M.; Lei, X.; Lellouch, J.; Li, D.; Li, H.; Li, L.; Li, Q. Z.; Lim, J. K.; Lincoln, D.; Linnemann, J.; Lipaev, V. V.; Lipton, R.; Liu, H.; Liu, Y.; Lobodenko, A.; Lokajicek, M.; Lopes de Sa, R.; Luna-Garcia, R.; Lyon, A. L.; Maciel, A. K. A.; Madar, R.; Magaña-Villalba, R.; Malik, S.; Malyshev, V. L.; Mansour, J.; Martínez-Ortega, J.; McCarthy, R.; McGivern, C. L.; Meijer, M. M.; Melnitchouk, A.; Menezes, D.; Mercadante, P. G.; Merkin, M.; Meyer, A.; Meyer, J.; Miconi, F.; Mondal, N. K.; Mulhearn, M.; Nagy, E.; Narain, M.; Nayyar, R.; Neal, H. A.; Negret, J. P.; Neustroev, P.; Nguyen, H. T.; Nunnemann, T.; Orduna, J.; Osman, N.; Osta, J.; Pal, A.; Parashar, N.; Parihar, V.; Park, S. K.; Partridge, R.; Parua, N.; Patwa, A.; Penning, B.; Perfilov, M.; Peters, Y.; Petridis, K.; Petrillo, G.; Pétroff, P.; Pleier, M. -A.; Podstavkov, V. M.; Popov, A. V.; Prewitt, M.; Price, D.; Prokopenko, N.; Qian, J.; Quadt, A.; Quinn, B.; Raja, R.; Ratoff, P. N.; Razumov, I.; Ripp-Baudot, I.; Rizatdinova, F.; Rominsky, M.; Ross, A.; Royon, C.; Rubinov, P.; Ruchti, R.; Sajot, G.; Sánchez-Hernández, A.; Sanders, M. P.; Santos, A. S.; Savage, G.; Sawyer, L.; Scanlon, T.; Schamberger, R. D.; Scheglov, Y.; Schellman, H.; Schwanenberger, C.; Schwienhorst, R.; Sekaric, J.; Severini, H.; Shabalina, E.; Shary, V.; Shaw, S.; Shchukin, A. A.; Simak, V.; Skubic, P.; Slattery, P.; Smirnov, D.; Snow, G. R.; Snow, J.; Snyder, S.; Söldner-Rembold, S.; Sonnenschein, L.; Soustruznik, K.; Stark, J.; Stoyanova, D. A.; Strauss, M.; Suter, L.; Svoisky, P.; Titov, M.; Tokmenin, V. V.; Tsai, Y. -T.; Tsybychev, D.; Tuchming, B.; Tully, C.; Uvarov, L.; Uvarov, S.; Uzunyan, S.; Van Kooten, R.; van Leeuwen, W. M.; Varelas, N.; Varnes, E. W.; Vasilyev, I. A.; Verkheev, A. Y.; Vertogradov, L. S.; Verzocchi, M.; Vesterinen, M.; Vilanova, D.; Vokac, P.; Wahl, H. D.; Wang, M. H. L. S.; Warchol, J.; Watts, G.; Wayne, M.; Weichert, J.; Welty-Rieger, L.; Williams, M. R. J.; Wilson, G. W.; Wobisch, M.; Wood, D. R.; Wyatt, T. R.; Xie, Y.; Yamada, R.; Yang, S.; Yasuda, T.; Yatsunenko, Y. A.; Ye, W.; Ye, Z.; Yin, H.; Yip, K.; Youn, S. W.; Yu, J. M.; Zennamo, J.; Zhao, T. G.; Zhou, B.; Zhu, J.; Zielinski, M.; Zieminska, D.; Zivkovic, L.

    2014-06-01

    The electron and photon reconstruction and identification algorithms used by the D0 Collaboration at the Fermilab Tevatron collider are described. The determination of the electron energy scale and resolution is presented. Studies of the performance of the electron and photon reconstruction and identification are summarized.

  1. Detector LENS as a new tool for solar neutrino spectroscopy

    International Nuclear Information System (INIS)

    Kornoukhov, V.N.

    2001-01-01

    LENS detector is a low-threshold, electron-flavor specific detector for real time measurement of the solar neutrino spectrum at low energies. It is expected that 20 tons of Yb used as a neutrino target should give several hundred events per year. The basic method for implementation of the LENS detector is scintillator technique, namely a liquid scintillator doped (up to 10% in mass) with natural Yb

  2. Search for WH Associated Production in the l upsilon b-bbar Final State Using the DØ Detector at the Tevatron

    Energy Technology Data Exchange (ETDEWEB)

    Brown, Jonathan [Paris Diderot Univ. (France)

    2011-09-15

    The Standard Model is the framework which allows to describe interactions between particles and their dynamics. The Higgs mechanism is a solution to naturally introduce a mass term in the theoretical description of this model. After electroweak spontaneous symmetry breaking, a new massive scalar particle is introduced, the Higgs boson. Since it hasn’t been discovered yet, the search for the Higgs boson is carried at the Tevatron, which is a p$\\bar{p}$ collider at a center-of-mass of 1.96 TeV. For MH <115 GeV, the dominant decay mode is H → b$\\bar{b}$ . The analysis presented in this document is focused on the 100< MH <150 GeV mass range, in the channel where the Higgs boson is produced in assocation with a W boson which decays either to an electron or muon and a neutrino. The study of this final state relies on informations collected from all parts of the DØ detector. A result based on 5.3 fb-1 of RunII Tevatron collisions is presented here. In order to increase the sensitivity to the signal, the analysis is separated in different sub-channels according to the lepton flavour, number of jets in the final state, number of jets identified as originated from b quarks and data taking periods. After selecting events, a multivariate analysis technique is used to separate signal-like events from the expected physics and instrumental backgrounds. A good agreement between data and simulation is observed. As no signal excess is observed in data, an observed (expected) upper limit of 4.5 (4.8) for MH = 115 GeV is set on the ratio of the WH cross section multiplied by the H → b$\\bar{b}$ branching fraction to its standard model prediction, at 95% confidence level. Since the final Tevatron dataset is soon to be analyzed, an effort is brought to achieve the maximum sensitivity. A preliminary analysis updated in Summer 2011 is presented as well as future improvements to be considered in the final publication for the search in

  3. Measurement of cross section of quark pair production top with the D0 experiment at the Tevatron and determination the top quark mass using this measure

    Energy Technology Data Exchange (ETDEWEB)

    Chevalier-Thery, Solene [Univ. Pierre et Marie Curie, Paris (France)

    2010-06-01

    The top quark has been discovered by CDF and D0 experiments in 1995 at the proton-antiproton collider Tevatron. The amount of data recorded by both experiments makes it possible to accurately study the properties of this quark: its mass is now known to better than 1% accuracy. This thesis describes the measurement of the top pair cross section in the electron muon channel with 4, 3 fb -1 recorded data between 2006 and 2009 by the D0 experiment. Since the final state included a muon, improvements of some aspects of its identification have been performed : a study of the contamination of the cosmic muons and a study of the quality of the muon tracks. The cross section measurement is in good agreement with the theoretical calculations and the other experimental measurements. This measurement has been used to extract a value for the top quark mass. This method allows for the extraction of a better defined top mass than direct measurements as it depends less on Monte Carlo simulations. The uncertainty on this extracted mass, dominated by the experimental one, is however larger than for direct measurements. In order to decrease this uncertainty, the ratio of the Z boson and the top pair production cross sections has been studied to look for some possible theoretical correlations. At the Tevatron, the two cross sections are not theoretically correlated: no decrease of the uncertainty on the extracted top mass is therefore possible.

  4. Cathode Lens Mode of the SEM in Materials Science Applications

    Czech Academy of Sciences Publication Activity Database

    Frank, Luděk; Müllerová, Ilona; Matsuda, K.; Ikeno, S.

    2007-01-01

    Roč. 48, č. 5 (2007), s. 944-948 ISSN 1345-9678 R&D Projects: GA ČR GA102/05/2327; GA ČR GA202/04/0281 Institutional research plan: CEZ:AV0Z20650511 Keywords : electron microscopy of materials * scanning electron microscopy * low energy electron microscopy * cathode lens Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 1.018, year: 2007

  5. [Correct contact lens hygiene].

    Science.gov (United States)

    Blümle, S; Kaercher, T; Khaireddin, R

    2013-06-01

    Although contact lenses have long been established in ophthalmology, practical aspects of handling contact lenses is becoming increasingly less important in the clinical training as specialist for ophthalmology. Simultaneously, for many reasons injuries due to wearing contact lenses are increasing. In order to correct this discrepancy, information on contact lenses and practical experience with them must be substantially increased from a medical perspective. This review article deals with the most important aspects for prevention of complications, i.e. contact lens hygiene.

  6. Forward-Backward Asymmetry of Top Quark Pair Productionn at the Fermilab Tevatron

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Ziqing [Texas A & M Univ., College Station, TX (United States)

    2015-12-01

    This dissertation presents the final measurements of the forward-backward asymmetry (AFB) of top quark-antiquark pair events (t t-) at the Collider Detector at Fermilab (CDF) experiment. The t t- events are produced in proton{anti-proton collisions with a center of mass energy of 1:96 TeV during the Run II of the Fermilab Tevatron. The measurements are performed with the full CDF Run II data (9.1 fb-1) in the final state that contain two charged leptons (electrons or muons, the dilepton final state), and are designed to con rm or deny the evidence-level excess in the AFB measurements in the final state with a single lepton and hadronic jets (lepton+jets final state) as well as the excess in the preliminary measurements in the dilepton final state with the first half of the CDF Run II data. New measurements include the leptonic AFB (AlFB), the lepton-pair AFB (All FB) and the reconstructed top AFB (At t FB). Each are combined with the previous results from the lepton+jets final state measured at the CDF experiment. The inclusive Al FB, All FB, and At t FB measured in the dilepton final state are 0.072 ± 0.060, 0.076 ± 0.081, and 0.12 ± 0.13, to be compared with the Standard Model (SM) predictions of 0.038 ± 0.003, 0.048 ± 0.004, and 0.010 ± 0.006, respectively. The CDF combination of AlFB and At t FB are 0.090+0:028 -0.026, and 0.160 ± 0.045, respectively. The overall results are consistent with the SM predictions.

  7. Prolonging contact lens wear and making contact lens wear safer.

    Science.gov (United States)

    Foulks, Gary N

    2006-02-01

    To summarize the present status of safety and efficacy of contact lens wear. Literature review. Ovid Medline searches were performed on records from 1966 through 2005 using keywords: keratitis, contact lens complications, extended-wear contact lenses, and silicone-hydrogel contact lenses. Patients desire comfort, clarity of vision, and prolonged contact lens wear when contact lenses are used to correct refractive error. Practitioners desire patient satisfaction but also require maintenance of the integrity of the eye and no complications that jeopardize vision or health of the eye. Improvements in the oxygen permeability of the contact lens materials, design of the contact lens and its surface, and solutions for the maintenance of the lens have reduced but not eliminated the risks of infection, inflammation, and conjunctival papillary reaction associated with contact lens wear. The lessons of past and recent history suggest that patient education and practitioner participation in the management of contact lens wear continue to be critical factors for patient satisfaction and safety in the extended wear of contact lenses. The availability of highly oxygen permeable contact lenses has increased the tolerance and safety of extended contact lens wear, but patient instruction and education in proper use and care of lenses is required and caution is advised.

  8. Studies of time dependence of fields in TEVATRON superconducting dipole magnets

    International Nuclear Information System (INIS)

    Hanft, R.W.; Brown, B.C.; Herrup, D.A.; Lamm, M.J.; McInturff, A.D.; Syphers, M.J.

    1988-01-01

    The time variation in the magnetic field of a model Tevatron dipole magnet at constant excitation current has been studied. Variations in symmetry allowed harmonic components over long time ranges show a log t behavior indicative of ''flux creep.'' Both short time range and long time range behavior depend in a detailed way on the excitation history. Similar effects are seen in the remnant fields present in full-scale Tevatron dipoles following current ramping. Both magnitudes and time dependences are observed to depend on details for the ramps, such as ramp rate, flattop duration, and number of ramps. In a few magnets, variations are also seen in symmetry unallowed harmonics. 9 refs., 10 figs

  9. Search for Resonant Second Generation Slepton Production at the Fermilab Tevatron

    Science.gov (United States)

    Abazov, V. M.; Abbott, B.; Abolins, M.; Acharya, B. S.; Adams, M.; Adams, T.; Agelou, M.; Agram, J.-L.; Ahn, S. H.; Ahsan, M.; Alexeev, G. D.; Alkhazov, G.; Alton, A.; Alverson, G.; Alves, G. A.; Anastasoaie, M.; Andeen, T.; Anderson, S.; Andrieu, B.; Anzelc, M. S.; Arnoud, Y.; Arov, M.; Askew, A.; Åsman, B.; Jesus, A. C. S. Assis; Atramentov, O.; Autermann, C.; Avila, C.; Ay, C.; Badaud, F.; Baden, A.; Bagby, L.; Baldin, B.; Bandurin, D. V.; Banerjee, P.; Banerjee, S.; Barberis, E.; Bargassa, P.; Baringer, P.; Barnes, C.; Barreto, J.; Bartlett, J. F.; Bassler, U.; Bauer, D.; Bean, A.; Begalli, M.; Begel, M.; Belanger-Champagne, C.; Bellantoni, L.; Bellavance, A.; Benitez, J. A.; Beri, S. B.; Bernardi, G.; Bernhard, R.; Berntzon, L.; Bertram, I.; Besançon, M.; Beuselinck, R.; Bezzubov, V. A.; Bhat, P. C.; Bhatnagar, V.; Binder, M.; Biscarat, C.; Black, K. M.; Blackler, I.; Blazey, G.; Blekman, F.; Blessing, S.; Bloch, D.; Bloom, K.; Blumenschein, U.; Boehnlein, A.; Boeriu, O.; Bolton, T. A.; Borcherding, F.; Borissov, G.; Bos, K.; Bose, T.; Brandt, A.; Brock, R.; Brooijmans, G.; Bross, A.; Brown, D.; Buchanan, N. J.; Buchholz, D.; Buehler, M.; Buescher, V.; Burdin, S.; Burke, S.; Burnett, T. H.; Busato, E.; Buszello, C. P.; Butler, J. M.; Calfayan, P.; Calvet, S.; Cammin, J.; Caron, S.; Carvalho, W.; Casey, B. C. K.; Cason, N. M.; Castilla-Valdez, H.; Chakrabarti, S.; Chakraborty, D.; Chan, K. M.; Chandra, A.; Chapin, D.; Charles, F.; Cheu, E.; Chevallier, F.; Cho, D. K.; Choi, S.; Choudhary, B.; Christofek, L.; Claes, D.; Clément, B.; Clément, C.; Coadou, Y.; Cooke, M.; Cooper, W. E.; Coppage, D.; Corcoran, M.; Cousinou, M.-C.; Cox, B.; Crépé-Renaudin, S.; Cutts, D.; Ćwiok, M.; da Motta, H.; Das, A.; Das, M.; Davies, B.; Davies, G.; Davis, G. A.; de, K.; de Jong, P.; de Jong, S. J.; de La Cruz-Burelo, E.; de Oliveira Martins, C.; Degenhardt, J. D.; Déliot, F.; Demarteau, M.; Demina, R.; Demine, P.; Denisov, D.; Denisov, S. P.; Desai, S.; Diehl, H. T.; Diesburg, M.; Doidge, M.; Dominguez, A.; Dong, H.; Dudko, L. V.; Duflot, L.; Dugad, S. R.; Duperrin, A.; Dyer, J.; Dyshkant, A.; Eads, M.; Edmunds, D.; Edwards, T.; Ellison, J.; Elmsheuser, J.; Elvira, V. D.; Eno, S.; Ermolov, P.; Estrada, J.; Evans, H.; Evdokimov, A.; Evdokimov, V. N.; Fatakia, S. N.; Feligioni, L.; Ferapontov, A. V.; Ferbel, T.; Fiedler, F.; Filthaut, F.; Fisher, W.; Fisk, H. E.; Fleck, I.; Ford, M.; Fortner, M.; Fox, H.; Fu, S.; Fuess, S.; Gadfort, T.; Galea, C. F.; Gallas, E.; Galyaev, E.; Garcia, C.; Garcia-Bellido, A.; Gardner, J.; Gavrilov, V.; Gay, A.; Gay, P.; Gelé, D.; Gelhaus, R.; Gerber, C. E.; Gershtein, Y.; Gillberg, D.; Ginther, G.; Gollub, N.; Gómez, B.; Gounder, K.; Goussiou, A.; Grannis, P. D.; Greenlee, H.; Greenwood, Z. D.; Gregores, E. M.; Grenier, G.; Gris, Ph.; Grivaz, J.-F.; Grünendahl, S.; Grünewald, M. W.; Guo, F.; Guo, J.; Gutierrez, G.; Gutierrez, P.; Haas, A.; Hadley, N. J.; Haefner, P.; Hagopian, S.; Haley, J.; Hall, I.; Hall, R. E.; Han, L.; Hanagaki, K.; Harder, K.; Harel, A.; Harrington, R.; Hauptman, J. M.; Hauser, R.; Hays, J.; Hebbeker, T.; Hedin, D.; Hegeman, J. G.; Heinmiller, J. M.; Heinson, A. P.; Heintz, U.; Hensel, C.; Hesketh, G.; Hildreth, M. D.; Hirosky, R.; Hobbs, J. D.; Hoeneisen, B.; Hoeth, H.; Hohlfeld, M.; Hong, S. J.; Hooper, R.; Houben, P.; Hu, Y.; Hubacek, Z.; Hynek, V.; Iashvili, I.; Illingworth, R.; Ito, A. S.; Jabeen, S.; Jaffré, M.; Jain, S.; Jakobs, K.; Jarvis, C.; Jenkins, A.; Jesik, R.; Johns, K.; Johnson, C.; Johnson, M.; Jonckheere, A.; Jonsson, P.; Juste, A.; Käfer, D.; Kahn, S.; Kajfasz, E.; Kalinin, A. M.; Kalk, J. M.; Kalk, J. R.; Kappler, S.; Karmanov, D.; Kasper, J.; Kasper, P.; Katsanos, I.; Kau, D.; Kaur, R.; Kehoe, R.; Kermiche, S.; Kesisoglou, S.; Khalatyan, N.; Khanov, A.; Kharchilava, A.; Kharzheev, Y. M.; Khatidze, D.; Kim, H.; Kim, T. J.; Kirby, M. H.; Klima, B.; Kohli, J. M.; Konrath, J.-P.; Kopal, M.; Korablev, V. M.; Kotcher, J.; Kothari, B.; Koubarovsky, A.; Kozelov, A. V.; Kozminski, J.; Kryemadhi, A.; Krzywdzinski, S.; Kuhl, T.; Kumar, A.; Kunori, S.; Kupco, A.; Kurča, T.; Kvita, J.; Lager, S.; Lammers, S.; Landsberg, G.; Lazoflores, J.; Bihan, A.-C. Le; Lebrun, P.; Lee, W. M.; Leflat, A.; Lehner, F.; Lesne, V.; Leveque, J.; Lewis, P.; Li, J.; Li, Q. Z.; Lima, J. G. R.; Lincoln, D.; Linnemann, J.; Lipaev, V. V.; Lipton, R.; Liu, Z.; Lobo, L.; Lobodenko, A.; Lokajicek, M.; Lounis, A.; Love, P.; Lubatti, H. J.; Lynker, M.; Lyon, A. L.; Maciel, A. K. A.; Madaras, R. J.; Mättig, P.; Magass, C.; Magerkurth, A.; Magnan, A.-M.; Makovec, N.; Mal, P. K.; Malbouisson, H. B.; Malik, S.; Malyshev, V. L.; Mao, H. S.; Maravin, Y.; Martens, M.; Mattingly, S. E. K.; McCarthy, R.; McCroskey, R.; Meder, D.; Melnitchouk, A.; Mendes, A.; Mendoza, L.; Merkin, M.; Merritt, K. W.

    2006-09-01

    We present a search for supersymmetry in the R-parity violating resonant production and decay of smuons and muon sneutrinos in the channels μ˜→χ˜10μ, μ˜→χ˜2,3,40μ, and ν˜μ→χ˜1,2±μ. We analyzed 0.38fb-1 of integrated luminosity collected between April 2002 and August 2004 with the D0 detector at the Fermilab Tevatron Collider. The observed number of events is in agreement with the standard model expectation, and we calculate 95% C.L. limits on the slepton production cross section times branching fraction to gaugino plus muon, as a function of slepton and gaugino masses. In the framework of minimal supergravity, we set limits on the coupling parameter λ211', extending significantly previous results obtained in Run I of the Tevatron and at the CERN LEP collider.

  10. Measurement of Beam Tunes in the Tevatron Using the BBQ System

    Energy Technology Data Exchange (ETDEWEB)

    Edstrom, Dean R.; /Indiana U.

    2009-04-01

    Measuring the betatron tunes in any synchrotron is of critical importance to ensuring the stability of beam in the synchrotron. The Base Band Tune, or BBQ, measurement system was developed by Marek Gasior of CERN and has been installed at Brookhaven and Fermilab as a part of the LHC Accelerator Research Program, or LARP. The BBQ was installed in the Tevatron to evaluate its effectiveness at reading proton and antiproton tunes at its flattop energy of 980 GeV. The primary objectives of this thesis are to examine the methods used to measure the tune using the BBQ tune measurement system, to incorporate the system into the Fermilab accelerator controls system, ACNET, and to compare the BBQ to existing tune measurement systems in the Tevatron.

  11. Plasma lens experiments at the Final Focus Test Beam

    International Nuclear Information System (INIS)

    Barletta, B.; Chattopadhyay, S.; Chen, P.

    1993-04-01

    We intend to carry out a series of plasma lens experiments at the Final Focus Test Beam facility at SLAC. These experiments will be the first to study the focusing of particle beams by plasma focusing devices in the parameter regime of interest for high energy colliders, and is expected to lead to plasma lens designs capable of unprecedented spot sizes. Plasma focusing of positron beams will be attempted for the first time. We will study the effects of lens aberrations due to various lens imperfections. Several approaches will be applied to create the plasma required including laser ionization and beam ionization of a working gas. At an increased bunch population of 2.5 x 10 10 , tunneling ionization of a gas target by an electron beam -- an effect which has never been observed before -- should be significant. The compactness of our device should prove to be of interest for applications at the SLC and the next generation linear colliders

  12. Plasma lens experiments at the Final Focus Test Beam

    Energy Technology Data Exchange (ETDEWEB)

    Barletta, B. [California Univ., Los Angeles, CA (United States)]|[Lawrence Berkeley Lab., CA (United States); Chattopadhyay, S. [Lawrence Berkeley Lab., CA (United States); Chen, P. [Stanford Linear Accelerator Center, Menlo Park, CA (United States)] [and others

    1993-04-01

    We intend to carry out a series of plasma lens experiments at the Final Focus Test Beam facility at SLAC. These experiments will be the first to study the focusing of particle beams by plasma focusing devices in the parameter regime of interest for high energy colliders, and is expected to lead to plasma lens designs capable of unprecedented spot sizes. Plasma focusing of positron beams will be attempted for the first time. We will study the effects of lens aberrations due to various lens imperfections. Several approaches will be applied to create the plasma required including laser ionization and beam ionization of a working gas. At an increased bunch population of 2.5 {times} 10{sup 10}, tunneling ionization of a gas target by an electron beam -- an effect which has never been observed before -- should be significant. The compactness of our device should prove to be of interest for applications at the SLC and the next generation linear colliders.

  13. Top quark production cross-section at the Tevatron Run 2

    OpenAIRE

    Cabrera, S.

    2003-01-01

    The top quark pair production cross-section ${\\sigma}_{t\\bar{t}}$ has been measured in $p\\bar{p}$ collisions at center of mass energies of 1.96 TeV using Tevatron Run 2 data. In the begining of Run 2 both CDF and D\\O\\ $\\sigma_{t\\bar{t}}$ measurements in the {\\it dilepton} channel $t\\bar{t}{\\to}WbW\\bar{b}{\\to}\\bar{\\ell}{\

  14. High-pT W and Z production at the Fermilab Tevatron

    International Nuclear Information System (INIS)

    Arnold, P.; Ellis, R.K.; Reno, M.H.

    1989-01-01

    In previous work, we and others have put together a full computation of dσ/dq T for the inclusive production of high-transverse-momentum W's and Z's to second order in QCD. Here, we present the results in graphs from which relevant cross sections may be extracted at a glance. Specifically, we plot dσ/dq T and ∫ q T dq T (dσ/dq T ) for the Fermilab Tevatron

  15. Experimental interplay between the top quark and Supersymmetry at the LHC and Tevatron

    CERN Document Server

    Arguin, JF; The ATLAS collaboration

    2013-01-01

    The search for Supersymmetry is of highest priority for the physics programs of the LHC and Tevatron experiments. The top quark plays an important role in this quest, both as a dominant background and as a key signature for the signal, in particular in the decay of third generation squarks. We review the latest status of the interplay of top quark and SUSY at hadron colliders.

  16. Design and operation of the quench protection system for the Fermilab Tevatron

    International Nuclear Information System (INIS)

    Martin, P.S.

    1986-05-01

    A method is required to protect the magnets of a superconducting accelerator from possible overheating or overvoltage conditions in the event that some magnets quench, that is, are elevated in temperature such that they are no longer superconducting. A brief discussion of the basic properties of superconductors and the phenomenon of quench propagation is given, followed by the configuration of a quench protection system for the Fermilab Tevatron

  17. Di-J/psi production at the Tevatron and the LHC

    CERN Document Server

    Lansberg, Jean-Philippe

    2016-01-01

    We briefly review recent results which we have obtained in the study of J/psi-pair production at the Tevatron and the LHC. We claim that the existing data set from CMS and D0 point at a significant double-parton-scattering contribution with an effective cross section smaller than that for jet-related observables. We have also derived simple relations involving feed-down fractions from excited states which can help in disentangling the single from the double scatterings.

  18. Consequences of the extra SM families on the Higgs boson production at Fermilab Tevatron and LHC

    CERN Document Server

    Arik, E; Cetin, S A; Sultansoy, S F

    2002-01-01

    The latest electroweak precission data allow the existence of additional chiral generations in the standard model. We study the influence of extra generations on the production of SM Higgs boson at hadron colliders. Due to the enhancement of the gluon fusion channel, the ``golden mode'' becomes more promising even at upgraded Tevatron. Furthermore, the formation of the fourth family quarkonia with the subsequent $\\eta_{4}\\to ZH$ decay introduces additional tool for the investigation of the Higgs boson properties.

  19. Forward-Backward Asymmetries in Top-Antitop Quark Production at the Tevatron

    Energy Technology Data Exchange (ETDEWEB)

    Aaltonen, Timo, A.

    2016-09-21

    We present the combined results on inclusive forward-backward asymmetries in the production of top-antitop quark pairs and their decay leptons. The analysis is based on measurements by the CDF and D0 experiments at the Fermilab $p\\bar{p}$ Tevatron collider using all the data collected at $\\sqrt{s}$ = 1:96 TeV. The measured asymmetries are in agreement with standard model predictions.

  20. Diffraction and Total Cross-Section at the Tevatron and the LHC

    CERN Document Server

    Deile, M; Aurola, A; Avati, V; Berardi, V; Bottigli, U; Bozzo, M; Brucken, E; Buzzo, A; Calicchio, M; Capurro, F; Catanesi, M G; Ciocci, M A; Cuneo, S; Da Vià, C; Dimovasili, E; Eggert, K; Eraluoto, M; Ferro, F; Giachero, A; Guillaud, J P; Hasi, J; Haug, F; Heino, J; Hilden, T; Jarron, P; Kalliopuska, J; Kaspar, J; Kempa, J; Kenney, C; Kok, A; Kundrát, V; Kurvinen, K; Lami, S; Lamsa, J; Latino, G; Lauhakangas, R; Lippmaa, J; Lokajícek, M; Lo Vetere, M; Macina, D; Macri, M; Meucci, M; Minutoli, S; Morelli, A; Musico, P; Negri, M; Niewiadomski, H; Noschis, E; Ojala, J; Oljemark, F; Orava, R; Oriunno, M; Österberg, K; Paoletti, R; Parker, S; Perrot, Anne Laure; Radermacher, E; Radicioni, E; Robutti, E; Ropelewski, Leszek; Ruggiero, G; Saarikko, H; Sanguinetti, G; Santroni, A; Saramad, S; Sauli, Fabio; Scribano, A; Sette, G; Smotlacha, J; Snoeys, W; Taylor, C; Toppinen, A; Turini, N; Van Remortel, N; Verardo, L; Verdier, A; Watts, S; Whitmore, J

    2006-01-01

    At the Tevatron, the total p_bar-p cross-section has been measured by CDF at 546 GeV and 1.8 TeV, and by E710/E811 at 1.8 TeV. The two results at 1.8 TeV disagree by 2.6 standard deviations, introducing big uncertainties into extrapolations to higher energies. At the LHC, the TOTEM collaboration is preparing to resolve the ambiguity by measuring the total p-p cross-section with a precision of about 1 %. Like at the Tevatron experiments, the luminosity-independent method based on the Optical Theorem will be used. The Tevatron experiments have also performed a vast range of studies about soft and hard diffractive events, partly with antiproton tagging by Roman Pots, partly with rapidity gap tagging. At the LHC, the combined CMS/TOTEM experiments will carry out their diffractive programme with an unprecedented rapidity coverage and Roman Pot spectrometers on both sides of the interaction point. The physics menu comprises detailed studies of soft diffractive differential cross-sections, diffractive structure func...

  1. PDF dependence of Higgs cross sections at the Tevatron and LHC: response to recent criticism

    CERN Document Server

    Thorne, R S

    2011-01-01

    We respond to some criticism questioning the validity of the current Standard Model Higgs exclusion limits at the Tevatron, due to the significant dependence of the dominant production cross section from gluon-gluon fusion on the choice of parton distribution functions (PDFs) and the strong coupling (alpha_S). We demonstrate the ability of the Tevatron jet data to discriminate between different high-x gluon distributions, performing a detailed quantitative comparison to show that fits not explicitly including these data fail to give a good description. In this context we emphasise the importance of the consistent treatment of luminosity uncertainties. We comment on the values of alpha_S obtained from fitting deep-inelastic scattering data, particularly the fixed-target NMC data, and we show that jet data are needed for stability. We conclude that the Higgs cross-section uncertainties due to PDFs and alpha_S currently used by the Tevatron and LHC experiments are not significantly underestimated, contrary to so...

  2. Electron and photon identification in the D0 experiment

    Czech Academy of Sciences Publication Activity Database

    Abazov, V. M.; Abbott, B.; Acharya, B.S.; Kupčo, Alexander; Lokajíček, Miloš

    Roč. 750, Jun ( 2014 ), s. 78-95 ISSN 0168-9002 R&D Projects: GA MŠk(CZ) LG12006 Institutional support: RVO:68378271 Keywords : electron and photon reconstruction * electron and photon identification * Tevatron Run II * D0 * DZero * Fermilab Subject RIV: BF - Elementary Particles and High Energy Physics Impact factor: 1.216, year: 2014

  3. Electron Lenses for particle collimation in LHC

    CERN Document Server

    Shiltsev, V

    2008-01-01

    Electron Lenses built and installed in Tevatron have proven themselves as safe and very reliable instruments which can be effectively used in hadron collider operation for a number of applications, including compensation of beam-beam effects , DC beam removal from abort gaps , as a diagnostic tool. In this presentation we – following original proposal – consider in more detail a possibility of using electron lenses with hollow electron beam for ion and proton collimation in LHC.

  4. Identification of τ leptons and research of the Higgs boson in the final state μ + τ in the DO experiment at the Tevatron

    International Nuclear Information System (INIS)

    Madar, R.

    2011-09-01

    The gauge symmetry is the heart of our understanding of the electroweak interaction and describes all the current experimental results. However, the intrinsic incompatibility between the gauge invariance and the mass of particles leads to the introduction of a new particle, the Higgs boson, for which we have no experimental evidence as of today. This thesis describes the Higgs boson search in the μ+τ final state in 7.3 fb -1 of pp-bar collisions at √(s) equals 1:96 TeV collected by the DO detector at the Tevatron. This analysis completes the golden channels (dimuons, electron-muon, di-electrons) exploiting the decay chain H → WW → lνlν which is the main Higgs boson decay mode in the mass window accessible to the Tevatron. Since the final state includes a τ lepton, work was done to improve their identification among jets. An increase of 15% was achieved thanks to the following: changing tuning parameters for the τ identification neural network, use of the kinematical dependence of the algorithm performances, incorporation of the τ lepton life time information and full study of the additional information coming from the central pre shower measurements. Then, since the dominant background of the μ+τ Higgs boson search is W+jets (where one jet fakes a τ), a method was developed to obtain good modeling of this background, not provided by the default simulation. This method is based, among other things, on the charge correlation between the muon and the τ candidate which allows for calibration of this background in the data excluding the signal region. Finally, all the kinematic and/or topological differences between the signal and the background were exploited to optimize this search, reaching an (observed) expected sensitivity of 7.8 (6.6) times the Standard Model for m H equals 165 GeV/c 2 . In addition, this result was also interpreted in a fourth fermion generation scenario. For the first time, this analysis is included in the DO and Tevatron

  5. Compliance among soft contact lens wearers.

    OpenAIRE

    Kuzman, Tomislav; Barišić Kutija, Marija; Masnec, Sanja; Jandroković, Sonja; Mrazovac, Danijela; Jurišić, Darija; Škegro, Ivan; Kalauz, Miro; Kordić, Rajko

    2014-01-01

    Contact lens compliance is proven to be crucial for preventing lens wear-related complications because of the interdependence of the steps in lens care regime and their influence on lens system microbial contamination. Awareness of the patients' lens handling compliance as well as correct recognition of non-compliant behaviours is the basis for creating more targeted strategies for patient education. The aim of this study was to investigate compliance among soft contact lens (SCL) wearers in ...

  6. Panoramic lens applications revisited

    Science.gov (United States)

    Thibault, Simon

    2008-04-01

    During the last few years, innovative optical design strategies to generate and control image mapping have been successful in producing high-resolution digital imagers and projectors. This new generation of panoramic lenses includes catadioptric panoramic lenses, panoramic annular lenses, visible/IR fisheye lenses, anamorphic wide-angle attachments, and visible/IR panomorph lenses. Given that a wide-angle lens images a large field of view on a limited number of pixels, a systematic pixel-to-angle mapping will help the efficient use of each pixel in the field of view. In this paper, we present several modern applications of these modern types of hemispheric lenses. Recently, surveillance and security applications have been proposed and published in Security and Defence symposium. However, modern hemispheric lens can be used in many other fields. A panoramic imaging sensor contributes most to the perception of the world. Panoramic lenses are now ready to be deployed in many optical solutions. Covered applications include, but are not limited to medical imaging (endoscope, rigiscope, fiberscope...), remote sensing (pipe inspection, crime scene investigation, archeology...), multimedia (hemispheric projector, panoramic image...). Modern panoramic technologies allow simple and efficient digital image processing and the use of standard image analysis features (motion estimation, segmentation, object tracking, pattern recognition) in the complete 360° hemispheric area.

  7. W boson production and mass at the Tevatron

    Energy Technology Data Exchange (ETDEWEB)

    Stelzer-Chilton, Oliver; /Toronto U.

    2005-06-01

    The CDF and D0 collaborations have analyzed up to {approx} 200 pb{sup -1} of Run 2 physics data to measure W production properties such as the W cross section, the W width, lepton universality and the W charge asymmetry. From the cross section measurements, CDF obtains a lepton universality of g{sub {mu}}/g{sub e} = 0.998 {+-} 0.012 and g{sub {tau}}/g{sub e} = 0.99 {+-} 0.04 and an indirect W width of {Lambda}{sub W} = 2079 {+-} 41 MeV. D0 measured the W width directly and finds {Lambda}{sub W} = 2011 {+-} 142 MeV. CDF has estimated the uncertainties on the W boson mass measurements in the electron and muon decay channels and obtains an overall uncertainty of 76 MeV.

  8. Two families of astrophysical diverging lens models

    Science.gov (United States)

    Er, Xinzhong; Rogers, Adam

    2018-03-01

    In the standard gravitational lensing scenario, rays from a background source are bent in the direction of a foreground lensing mass distribution. Diverging lens behaviour produces deflections in the opposite sense to gravitational lensing, and is also of astrophysical interest. In fact, diverging lensing due to compact distributions of plasma has been proposed as an explanation for the extreme scattering events that produce frequency-dependent dimming of extragalactic radio sources, and may also be related to the refractive radio wave phenomena observed to affect the flux density of pulsars. In this work we study the behaviour of two families of astrophysical diverging lenses in the geometric optics limit, the power law, and the exponential plasma lenses. Generally, the members of these model families show distinct behaviour in terms of image formation and magnification, however the inclusion of a finite core for certain power-law lenses can produce a caustic and critical curve morphology that is similar to the well-studied Gaussian plasma lens. Both model families can produce dual radial critical curves, a novel distinction from the tangential distortion usually produced by gravitational (converging) lenses. The deflection angle and magnification of a plasma lens vary with the observational frequency, producing wavelength-dependent magnifications that alter the amplitudes and the shape of the light curves. Thus, multiwavelength observations can be used to physically constrain the distribution of the electron density in such lenses.

  9. Crystalline lens radioprotectors

    International Nuclear Information System (INIS)

    Belkacemi, Y.; Pasquier, D.; Castelain, B.; Lartigau, E.; Warnet, J.M.

    2003-01-01

    During more than a half of century, numerous compounds have been tested in different models against radiation-induced cataract. In this report, we will review the radioprotectors that have been already tested for non-human crystalline lens protection. We will focus on the most important published studies in this topic and the mechanisms of cyto-protection reported in. vitro and in. vivo from animals. The most frequent mechanisms incriminated in the cyto-protective effect are: free radical scavenging, limitation of lipid peroxidation, modulation of cycle progression increase of intracellular reduced glutathione pool, reduction of DNA strand breaks and limitation of apoptotic cell death. Arnifostine (or Ethyol) and anethole dithiolethione (or Sulfarlem), already used clinically as chemo- and radio-protectants, could be further test?r for ocular radioprotection particularly for radiation-induced cataract. (author)

  10. Identification of $\\tau$ leptons and Higgs boson search in the $\\mu+\\tau$ final state at the D0 experiment at the Tevatron

    Energy Technology Data Exchange (ETDEWEB)

    Madar, Romain [Univ. of Paris, Orsay (France)

    2011-01-01

    The gauge symmetry is the heart of our understanding of the electroweak interaction and describes all the current experimental results. However, the intrinsic incompatibility between the gauge invariance and the mass of particles leads to the introduction of a new particle, the Higgs boson, for which we have no experimental evidence as of today. This thesis describes the Higgs boson search in the μ + τ final state in 7.3 fb-1 of pp collisions at √s = 1.96 TeV collected by the DØ detector at the Tevatron. This analysis completes the golden channels (dimuons, electron-muon, dielectrons) exploiting the decay chain H → WW → ℓvℓv , which is the main Higgs boson decay mode in the mass window accessible to the Tevatron. Since the final state includes a lepton, work was done to improve their identification among jets. An increase of 15% was achieved thanks to the the following : changing tuning parameters for the identification neural network, use of the kinematical dependence of the algorithm performances, incorporation of the τ lepton life time information and full study of the additionnal information coming from the central preshower measurements. Then, since the dominant background of the μ + τ Higgs boson search is W+jets (where one jet fakes a τ ), a method was developed to obtain good modeling of this background, not provided by the default simulation. This method is based, among other things, on the charge correlation between the muon and the τ candidate which allows for calibration of this background in the data excluding the signal region. Finally, all the kinematic and/or topological differences between the signal and the background were exploited to optimize this search, reaching an (observed) expected sensitivity of 7.8 (6.6) times the Standard Model for mH = 165 GeV=c2. In addition, this result was also interpreted in a fourth fermion generation scenario. For the first time, this analysis is included in the D

  11. Contact Lens Wear at Altitude: Subcontact Lens Bubble Formation

    Science.gov (United States)

    1987-11-01

    incidence of (PMMA) lenses . Reported here are the results of contact lens subcontact lens bubble formation under scleral lenses at bubble studies with soft...vision from formation of large bubbles greater than 6,096 m (20,000 It). With soft contact lenses , bubble under their contact lenses . They also found...always located at the limbus and were without sequela to vision or corneal epithelial integrity. scleral lenses used by Jaeckle were permeable to gases

  12. Reshimming of Tevatron Dipoles; A Process-Quality and Lessons-Learned Perspective

    CERN Document Server

    Blowers, James N; Harding, David J; John, Carson; Robotham, William

    2005-01-01

    Over the last two years corrections have been made for the skew quadrupole moment in 530 of the 774 installed dipoles in the Tevatron. This process of modifying the magnets in situ has inherent risk of degrading the performance of the superconducting accelerator. In order to manage the risk, as well as to ensure the corrections were done consistently, formal quality tools were used to plan and verify the work. The quality tools used to define the process and for quality control are discussed, along with highlights of lessons learned.

  13. Considerations of bunch-spacing options for multi-bunch operation of the Tevatron Collider

    International Nuclear Information System (INIS)

    Dugan, G.

    1989-01-01

    This discussion will consider a number of points relevant to limitations, advantages and disadvantages of various arrangements of bunches in the Tevatron proton-antiproton collider. The considerations discussed here will be limited to: (a) bunch spacing symmetry and relation to the relative luminosity at B0 and D0 and the beam-beam interaction with separated beams; (b) bunch spacing constraints imposed by Main Ring RF coalescing and the optics of beam separation at B0 and D0; and (c) bunch spacing constraints imposed by injection and abort kicker timing requirements, and by the Antiproton Source RF unstacking process. 20 figs., 17 tabs

  14. E710, $p\\bar{p}$ Elastic Scattering at Tevatron Energies

    Energy Technology Data Exchange (ETDEWEB)

    Sadr, Sasan [Northwestern Univ., Evanston, IL (United States)

    1993-11-01

    Experiment E710, located at site EO of the Tevatron collider at Fermilab, was conceived in order to measure $p\\bar{p}$ elastic scattering. The measured parameters were: the total cross section $\\sigma_t$, the ratio of the real to the imaginary part of the forward scattering amplitude $p$, the nuclear slope parameter B, the nuclear curvature parameter C, the total elastic cross section $\\sigma_{el}$, and the single diffractive cross section $\\sigma_{sd}$. These measurements were taken at center-of-mass energies of $\\sqrt{s}$= 1.02 and 1.8 TeV.

  15. Review of Physics Results from the Tevatron: Searches for New Particles and Interactions

    Energy Technology Data Exchange (ETDEWEB)

    Toback, David [Texas A-M; ŽIvković, Lidija [Belgrade U.

    2015-02-17

    We present a summary of results for searches for new particles and interactions at the Fermilab Tevatron collider by the CDF and the D0 experiments. These include results from Run I as well as Run II for the time period up to July 2014. We focus on searches for supersymmetry, as well as other models of new physics such as new fermions and bosons, various models of excited fermions, leptoquarks, technicolor, hidden-valley model particles, long-lived particles, extra dimensions, dark matter particles, and signature-based searches.

  16. Search for chargino and neutralino at Run II of the Tevatron Collider

    Energy Technology Data Exchange (ETDEWEB)

    Canepa, Anadi [Purdue Univ., West Lafayette, IN (United States)

    2006-08-01

    In this dissertation we present a search for the associated production of charginos and neutralinos, the supersymmetric partners of the Standard Model bosons. We analyze a data sample representing 745 pb-1 of integrated luminosity collected by the CDF experiment at the p$\\bar{p}$ Tevatron collider. We compare the Standard Model predictions with the observed data selecting events with three leptons and missing transverse energy. Finding no excess, we combine the results of our search with similar analyses carried out at CDF and set an upper limit on the chargino mass in SUSY scenarios.

  17. Microwave Schottky diagnostic systems for the Fermilab Tevatron, Recycler, and CERN Large Hadron Collider

    Directory of Open Access Journals (Sweden)

    Ralph J. Pasquinelli

    2011-07-01

    Full Text Available A means for noninvasive measurement of transverse and longitudinal characteristics of bunched beams in synchrotrons has been developed based on high sensitivity slotted waveguide pickups. The pickups allow for bandwidths exceeding hundreds of MHz while maintaining good beam sensitivity characteristics. Wide bandwidth is essential to allow bunch-by-bunch measurements by means of a fast gate. The Schottky detector system is installed and successfully commissioned in the Fermilab Tevatron, Recycler and CERN LHC synchrotrons. Measurement capabilities include tune, chromaticity, and momentum spread of single or multiple beam bunches in any combination. With appropriate calibrations, emittance can also be measured by integrating the area under the incoherent tune sidebands.

  18. Measurements of the masses, lifetimes and decay modes of hadrons at Tevatron

    Energy Technology Data Exchange (ETDEWEB)

    Dorigo, Mirco; /Trieste U. /INFN, Trieste

    2010-05-01

    The Tevatron provides 1.96 TeV p{bar p} collisions and allows for collection of rich b-hadron samples to the two experiments CDF and D0. The study of heavy flavor properties represents a fruitful opportunity to investigate the flavor sector of the Standard Model (SM) and to look for hints of New Physics (NP). Here we report the first measurement of polarization amplitudes in B{sub s}{sup 0} charmless decays, world leading results on b-hadron lifetimes, and measurements of several other properties of b-hadrons.

  19. Jet Substructure at the Tevatron and LHC: New results, new tools, new benchmarks

    CERN Document Server

    Altheimer, A; Asquith, L; Brooijmans, G; Butterworth, J; Campanelli, M; Chapleau, B; Cholakian, A E; Chou, J P; Dasgupta, M; Davison, A; Dolen, J; Ellis, S D; Essig, R; Fan, J J; Field, R; Fregoso, A; Gallicchio, J; Gershtein, Y; Gomes, A; Haas, A; Halkiadakis, E; Halyo, V; Hoeche, S; Hook, A; Hornig, A; Huang, P; Izaguirre, E; Jankowiak, M; Kribs, G; Krohn, D; Larkoski, A J; Lath, A; Lee, C; Lee, S J; Loch, P; Maksimovic, P; Martinez, M; Miller, D W; Plehn, T; Prokofiev, K; Rahmat, R; Rappoccio, S; Safonov, A; Salam, G P; Schumann, S; Schwartz, M D; Schwartzman, A; Seymour, M; Shao, J; Sinervo, P; Son, M; Soper, D E; Spannowsky, M; Stewart, I W; Strassler, M; Strauss, E; Takeuchi, M; Thaler, J; Thomas, S; Tweedie, B; Vasquez Sierra, R; Vermilion, C K; Villaplana, M; Vos, M; Wacker, J; Walker, D; Walsh, J R; Wang, L-T; Wilbur, S; Yavin, I; Zhu, W

    2012-01-01

    In this report we review recent theoretical progress and the latest experimental results in jet substructure from the Tevatron and the LHC. We review the status of and outlook for calculation and simulation tools for studying jet substructure. Following up on the report of the Boost 2010 workshop, we present a new set of benchmark comparisons of substructure techniques, focusing on the set of variables and grooming methods that are collectively known as "top taggers". To facilitate further exploration, we have attempted to collect, harmonise, and publish software implementations of these techniques.

  20. Straylight Measurements in Contact Lens Wear

    NARCIS (Netherlands)

    van der Meulen, Ivanka J. E.; Engelbrecht, Leonore A.; van Vliet, Johannes M. J.; Lapid-Gortzak, Ruth; Nieuwendaal, Carla P.; Mourits, Maarten P.; Schlingemann, Reinier O.; van den Berg, Thomas J. T. P.

    2010-01-01

    Purpose: (1) To quantify the effect of contact lens wear on straylight in rigid and soft contact lens wearers and (2) to relate findings to morphological changes and subjective complaints. Methods: Straylight was measured using the Oculus C-Quant during contact lens wear and after contact lens

  1. Boro-Silicate Polycapillary Lens for Collimation of X-Rays

    National Research Council Canada - National Science Library

    Chase, Michael

    1997-01-01

    .... The electron beam was deflected 30 degrees using a rare earth permanent magnet. The diverging x-rays incident upon the lens array were transported through total external reflection and directed out of the array onto a phosphor screen...

  2. Contact Lens Related Corneal Ulcer

    OpenAIRE

    Loh, KY; Agarwal, P

    2010-01-01

    A corneal ulcer caused by infection is one of the major causes of blindness worldwide. One of the recent health concerns is the increasing incidence of corneal ulcers associated with contact lens user especially if the users fail to follow specific instruction in using their contact lenses. Risk factors associated with increased risk of contact lens related corneal ulcers are: overnight wear, long duration of continuous wear, lower socio-economic classes, smoking, dry eye and poor hygiene. Th...

  3. Smart Reinvention of the Contact Lens with Graphene.

    Science.gov (United States)

    Choi, Kyoungjun; Park, Hyung Gyu

    2017-06-27

    With potential benefits to the 71 million contact lens users worldwide, contact lenses are being reinvented in the form of smart wearable electronics. In this issue of ACS Nano, Lee et al. report on the fascinating functions of a graphene-based smart contact lens that is able to protect eyes from electromagnetic waves and dehydration. Graphene and two-dimensional materials can be exploited in many opportunities in the development of smart contact lenses. Here, we briefly review and describe prospects for the future of smart contact lenses that incorporate graphene in their platforms.

  4. Multiple Parton Interactions in p$bar{p}$ Collisions in D0 Experiment at the Tevatron Collider

    Energy Technology Data Exchange (ETDEWEB)

    Golovanov, Georgy [Joint Inst. for Nuclear Research (JINR), Dubna (Russia)

    2016-01-01

    The thesis is devoted to the study of processes with multiple parton interactions (MPI) in a ppbar collision collected by D0 detector at the Fermilab Tevatron collider at sqrt(s) = 1.96 TeV. The study includes measurements of MPI event fraction and effective cross section, a process-independent parameter related to the effective interaction region inside the nucleon. The measurements are done using events with a photon and three hadronic jets in the final state. The measured effective cross section is used to estimate background from MPI for WH production at the Tevatron energy

  5. A course in lens design

    CERN Document Server

    Velzel, Chris

    2014-01-01

    A Course in Lens Design is an instruction in the design of image-forming optical systems. It teaches how a satisfactory design can be obtained in a straightforward way. Theory is limited to a minimum, and used to support the practical design work. The book introduces geometrical optics, optical instruments and aberrations. It gives a description of the process of lens design and of the strategies used in this process. Half of its content is devoted to the design of sixteen types of lenses, described in detail from beginning to end. This book is different from most other books on lens design because it stresses the importance of the initial phases of the design process: (paraxial) lay-out and (thin-lens) pre-design. The argument for this change of accent is that in these phases much information can be obtained about the properties of the lens to be designed. This information can be used in later phases of the design. This makes A Course in Lens Design a useful self-study book, and a suitable basis for an intro...

  6. Bound states of two gluinos at the Fermilab Tevatron and CERN LHC

    Energy Technology Data Exchange (ETDEWEB)

    Chikovani, E.; Kartvelishvili, V.; Shanidze, R.; Shaw, G. [High Energy Physics Institute, Tbilisi State University, Tbilisi, GE-380086, Republic of (Georgia)]|[Department of Physics and Astronomy, Schuster Laboratory, University of Manchester, Manchester M13 9PL (United Kingdom)

    1996-06-01

    We calculate the production cross sections for the vector and pseudoscalar bound states of two gluinos. It is shown that existing and future colliders imply a realistic chance of observing gluinonium as a narrow peak in the two-jet invariant mass spectrum. With an integrated luminosity of 0.2 fb{sup {minus}1} at the Fermilab Tevatron, and the high efficiency for tagging heavy quark jets at CDF, one should be able to detect vector gluinonium for gluino masses up to about 170 GeV, or up to about 260 GeV for an upgraded Tevatron with a center of mass energy of 2 TeV and an integrated luminosity of 1 fb{sup {minus}1}. The significantly higher energy and luminosity of the CERN LHC should allow pseudoscalar gluinonium to be detected for gluino masses up to about 1500 GeV for an assumed luminosity of 200 fb{sup {minus}1}. These results are insensitive to the details of supersymmetry models, provided that {ital R} parity is conserved and the gluinos are lighter than the squarks. In addition, gluinonium detection implies a relatively accurate measure of the gluino mass, which is difficult to determine by other means. {copyright} {ital 1996 The American Physical Society.}

  7. LHC Predictions from a Tevatron Anomaly in the Top Quark Forward-Backward Asymmetry

    Energy Technology Data Exchange (ETDEWEB)

    Bai, Yang; Hewett, JoAnne L.; Kaplan, Jared; Rizzo, Thomas G.; /SLAC

    2011-08-12

    We examine the implications of the recent CDF measurement of the top-quark forward-backward asymmetry, focusing on a scenario with a new color octet vector boson at 1-3 TeV. We study several models, as well as a general effective field theory, and determine the parameter space which provides the best simultaneous fit to the CDF asymmetry, the Tevatron top pair production cross section, and the exclusion regions from LHC dijet resonance and contact interaction searches. Flavor constraints on these models are more subtle and less severe than the literature indicates. We find a large region of allowed parameter space at high axigluon mass and a smaller region at low mass; we match the latter to an SU(3){sub 1} x SU(3){sub 2}/SU(3){sub c} coset model with a heavy vector-like fermion. Our scenario produces discoverable effects at the LHC with only 1-2 inverse femtobarns of luminosity at 7-8 TeV. Lastly, we point out that a Tevatron measurement of the b-quark forward-backward asymmetry would be very helpful in characterizing the physics underlying the top-quark asymmetry.

  8. Motivation and detectability of an invisibly-decaying Higgs boson at the Fermilab Tevatron

    CERN Document Server

    Martin, S P; Martin, Stephen P.; Wells, James D.

    1999-01-01

    A Higgs boson with mass below 150 GeV has a total decay width of less than 20 MeV into accessible Standard Model states. This narrow width means that the usual branching fractions for such a light Higgs boson are highly susceptible to any new particles to which it has unsuppressed couplings. In particular, there are many reasonable and interesting theoretical ideas that naturally imply an invisibly-decaying Higgs boson. The motivations include models with light supersymmetric neutralinos, spontaneously broken lepton number, radiatively generated neutrino masses, additional singlet scalar(s), or right-handed neutrinos in the extra dimensions of TeV gravity. We discuss these approaches to model building and their implications for Higgs boson phenomenology in future Tevatron runs. We find, for example, that the Tevatron with 30 fb^{-1} integrated luminosity can make a 3\\sigma observation in the l+ l- plus missing transverse energy channel for a 125 GeV Higgs boson that is produced with the same strength as the S...

  9. Calculation of integrated luminosity for beams stored in the Tevatron collider

    International Nuclear Information System (INIS)

    Finley, D.A.

    1989-01-01

    A model for calculating the integrated luminosity of beams stored in the Tevatron collider will be presented. The model determines the instantaneous luminosity by calculating the overlap integral of bunched beams passing through the interaction region. The calculation accounts for the variation in beam size due to the beta functions and also for effects due to finite longitudinal emittance and non-zero dispersion in the interaction region. The integrated luminosity is calculated for the beams as they evolve due to processes including collisions and intrabeam scattering. The model has been applied to both the extant and upgraded Tevatron collider, but is not limited to them. The original motivation for developing the computer model was to determine the reduction in luminosity due to beams with non-zero longitudinal emittances. There are two effects: the transverse beam size is increased where the dispersion is non-zero; the finite length of the beam bunch combined with an increasing β function results in an increased transverse beam size at the ends of the bunch. The derivation of a sufficiently useful analytic expression for the luminosity proved to be intractable. Instead, a numerical integration computer program was developed to calculate the luminosity in the presence of a finite longitudinal emittance. The program was then expanded into a model which allows the luminosity to vary due to changes in emittances and reduction in bunch intensities. At that point, it was not difficult to calculate the integrated luminosity. 5 refs., 2 figs., 4 tabs

  10. Channeling and Volume Reflection Based Crystal Collimation of Tevatron Circulating Beam Halo

    CERN Document Server

    Shiltsev, V.; Drozhdin, A.; Johnson, T.; Legan, A.; Mokhov, N.; Reilly, R.; Still, D.; Tesarek, R.; Zagel, J.; Peggs, S.; Assmann, R.; Previtali, V.; Scandale, W.; Chesnokov, Y.; Yazynin, I.; Guidi, V.; Ivanov, Y.

    2010-01-01

    The T980 crystal collimation experiment is underway at the Tevatron to determine if this technique could increase 980 GeV beam-halo collimation efficiency at high-energy hadron colliders such as the Tevatron and the LHC. T980 also studies various crystal types and parameters. The setup has been substantially enhanced during the Summer 2009 shutdown by installing a new O-shaped crystal in the horizontal goniometer, as well as adding a vertical goniometer with two alternating crystals (O-shaped and multi-strip) and additional beam diagnostics. First measurements with the new system are quite encouraging, with channeled and volume-reflected beams observed on the secondary collimators as predicted. Investigation of crystal collimation efficiencies with crystals in volume reflection and channeling modes are described in comparison with an amorphous primary collimator. Results on the system performance are presented for the end-of-store studies and for entire collider stores. The first investigation of colliding be...

  11. A framework of cloud supported collaborative design in glass lens moulds based on aspheric measurement

    Science.gov (United States)

    Zhu, Yongjian; Wang, Yu; Na, Jingxin; Zhi, Yanan; Fan, Yufeng

    2013-09-01

    Aspheric mould design includes the top-down design and reversal design. In this paper, a new framework of reversal design is proposed combining with cloud supported collaborative design (CSCD) based on aspheric measurement. The framework is a kind of collaborative platform, which is composed of eight modules, including the computerized aspheric precision measurement module (CAPM), computer-aided optical design of aspheric lens system (CAOD), computer-aided design of lens mould (CADLM), FEM(finite element method) simulation of lens molding module (FEMLM), computer-aided manufacture of lens and moulds (CAMLM), measurement data analysis module (MDAM), optical product lifecycle management module (OPLM) and cloud computing network module (CCNM). In this framework, the remote clients send an improved requirement or fabrication demand about optical lens system through CCNM, which transfers this signal to OPLM. In OPLM, one main server is in charge of the task distribution and collaborative work of other six modules. The first measurement data of aspheric lens are produced by clients or our proposed platform CAPM, then are sent to CAOD for optimization and the electronic drawings of lens moulds are generated in CADLM module. According the design drawings, the FEMLM could give the lens-molding simulation parameters through FEM software. The simulation data are used for the second design of moulds in CADLM module. In this case, the moulds could be fabricated in CAMLM by ultra-precision machine, and the aspheric lens could be also produced by lens-molding machine in CAMLM. At last, the final shape of aspheric lens could be measured in CAPM and the data analysis could be conducted in MDAM module. Through the proposed framework, all the work described above could be performed coordinately. And the optimum design data of lens mould could be realized and saved, then shared by all the work team.

  12. Bacterial and fungal biofilm formation on contact lenses and their susceptibility to lens care solutions

    Directory of Open Access Journals (Sweden)

    Siddharth Kackar

    2017-01-01

    Full Text Available Background: Microbial biofilm formation on contact lenses and lens storage cases may be a risk factor for contact lens-associated corneal infections. Various types of contact lens care solutions are used to reduce microbial growths on lenses. Objectives: The present study aimed at comparing the growths of biofilms on the different contact lenses and lens cases. The study also aimed at determining the effect of lens care solutions and bacteriophage on these biofilms. Materials and Methods: One type of hard lens and two types of soft lenses were used for the study. The organisms used were Staphylococcus aureus ATCC 25923, Pseudomonas aeruginosa ATCC 27853, Candida albicans ATCC 60193 and Escherichia coli ATCC 25922. Biofilm production was performed by modified O'Toole and Kolter method and effect of lens cleaning solutions and a crude coliphage on biofilms was also studied. Results were visualised using scanning electron microscopy and quantitated by colony counting method and spectrophotometric measurement of optical density (OD. Statistical analysis was done by SPSS 11.5, Kruskal–Wallis test and Chi-square test. Results: Soft lens cleaning solutions had a significant inhibitory effect (P = 0.020 on biofilm formation on soft lenses and also lens cases (P < 0.001. Soft lens cleaning solution 2 was more efficient than solution 1. However, no such inhibitory effect was observed with regard to hard lens cleaning solution, but for a significant reduction in the OD values (P < 0.001. There was no significant inhibitory effect by bacteriophages. Conclusion: This study showed the importance of selecting the appropriate lens cleaning solution to prevent biofilm production on contact lenses.

  13. Experimental Study of W Z Intermediate Bosons Associated Production with the CDF Experiment at the Tevatron Collider

    Energy Technology Data Exchange (ETDEWEB)

    Pozzobon, Nicola; /Pisa U.

    2007-09-01

    Studying WZ associated production at the Fermilab Tevatron Collider is of great importance for two main reasons. On the one hand, this process would be sensitive to anomalies in the triple gauge couplings such that any deviation from the value predicted by the Standard Model would be indicative of new physics. In addition, by choosing to focus on the final state where the Z boson decays to b{bar b} pairs, the event topology would be the same as expected for associated production of a W and a Standard Model light Higgs boson (m{sub H} {approx}< 135 GeV) which decays into b{bar b} pairs most of times. The process WH {yields} W b{bar b} has an expected {sigma} {center_dot} B about five times lower than WZ {yields} Wb{bar b} for m{sub H} {approx_equal} 120 GeV. Therefore, observing this process would be a benchmark for an even more difficult search aiming at discovering the light Higgs in the WH {yields} Wb{bar b} process. After so many years of Tevatron operation only a weak WZ signal was recently observed in the full leptonic decay channel, which suffers from much less competition from background. Searching for the Z in the b{bar b} decay channel in this process is clearly a very challenging endeavour. In the work described in this thesis, WZ production is searched for in a final state where the W decays leptonically to an electron-neutrino pair or a muon-neutrino pair, with associated production of a jet pair consistent with Z decays. A set of candidate events is obtained by applying appropriate cuts to the parameters of events collected by wide acceptance leptonic triggers. To improve the signal fraction of the selected events, an algorithm was used to tag b-flavored jets by means of their content of long lived b-hadrons and corrections were developed to the jet algorithm to improve the b-jet energy resolution for a better reconstruction of the Z mass. In order to sense the presence of a signal one needs to estimate the amount of background. The relative content of

  14. Search for supersymmetric Higgs bosons in the D0 experiment at the Tevatron; Recherche de bosons de Higgs supersymetriques au Tevatron dans l'experience D0

    Energy Technology Data Exchange (ETDEWEB)

    Michaut, M

    2006-09-15

    A search for the neutral Higgs bosons of the minimal supersymmetric extension of the standard model is performed in the 3 or 4 jets channels, pp-bar {yields} {phi}({yields} bb-bar)b(b-bar) with {phi} = h, H or A. For this purpose, the data collected with the D0 detector from 2002 to 2006 at the Tevatron hadronic collider with a center of mass energy of 1.96 TeV are analyzed. A complete study of the triggering is first done. The triggering conditions are optimized in order to keep the more signal fraction possible. Furthermore, a method is developed to predict the triggering efficiencies on our signal and backgrounds using only the data. Then an analysis method that allows the prediction of our background without the help of simulations is studied. No excess in events is observed in the data sample analyzed, corresponding to an integrated luminosity of 0.9 fb{sup -1}, so limits are set in the minimal supersymmetric extension of the standard model. At 95% confidence level, the following limits are found: tan({beta}) < 46 - 121 for m{sub {phi}} equals 100 - 170 GeV. (author)

  15. Time lens assisted photonic sampling extraction

    Science.gov (United States)

    Petrillo, Keith Gordon

    Telecommunication bandwidth demands have dramatically increased in recent years due to Internet based services like cloud computing and storage, large file sharing, and video streaming. Additionally, sensing systems such as wideband radar, magnetic imaging resonance systems, and complex modulation formats to handle large data transfer in telecommunications require high speed, high resolution analog-to-digital converters (ADCs) to interpret the data. Accurately processing and acquiring the information at next generation data rates from these systems has become challenging for electronic systems. The largest contributors to the electronic bottleneck are bandwidth and timing jitter which limit speed and reduce accuracy. Optical systems have shown to have at least three orders of magnitude increase in bandwidth capabilities and state of the art mode locked lasers have reduced timing jitters into thousands of attoseconds. Such features have encouraged processing signals without the use of electronics or using photonics to assist electronics. All optical signal processing has allowed the processing of telecommunication line rates up to 1.28 Tb/s and high resolution analog-to-digital converters in the 10s of gigahertz. The major drawback to these optical systems is the high cost of the components. The application of all optical processing techniques such as a time lens and chirped processing can greatly reduce bandwidth and cost requirements of optical serial to parallel converters and push photonically assisted ADCs into the 100s of gigahertz. In this dissertation, the building blocks to a high speed photonically assisted ADC are demonstrated, each providing benefits to its own respective application. A serial to parallel converter using a continuously operating time lens as an optical Fourier processor is demonstrated to fully convert a 160-Gb/s optical time division multiplexed signal to 16 10-Gb/s channels with error free operation. Using chirped processing, an

  16. Experimental results on $t\\bar{t}+W/Z/\\gamma$ and SM top couplings from the Tevatron and the LHC

    CERN Document Server

    Vazquez Schroeder, Tamara

    2014-01-01

    Experimental results from the CDF and D0 Collaborations at the Tevatron and the ATLAS and CMS Collaborations at the LHC on the processes related to probing top quark couplings are presented. Evidence of both $t\\bar{t}Z$ and $t\\bar{t}W$ processes is reported. All measurements are in agreement with the SM expectations.

  17. [Contact lens care and maintenance].

    Science.gov (United States)

    Bloise, L

    2017-04-01

    All contact lenses with replacement schedules longer than daily must be maintained. At each step of their use, the lenses may be contaminated. Contact lens solutions perform the essential functions of cleaning, decontaminating and preserving the lenses to prevent infectious problems and improve wearing comfort. Contact lens contamination essentially comes from hands, cleaning solutions, cases, water and the environment. The pathogenic microorganisms are mainly Gram-negative bacteria, fungi and amoebae. Contact lens deposits may or may not have an organic origin. Their presence increases the risk of infection because they serve as a nutrient matrix for microbes, and they are responsible for wearing discomfort. Contact lens solutions differ in their composition, their mechanism of action and the concentration of the various agents. To prescribe the best lens care system to each wearer and for each material, it is necessary to be very familiar with them. Maintenance is the main cause of discomfort with contact lenses, either through improper use, solution-material incompatibility, or a reaction of the wearer to the components. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  18. The SNAP Strong Lens Survey

    Energy Technology Data Exchange (ETDEWEB)

    Marshall, P.

    2005-01-03

    Basic considerations of lens detection and identification indicate that a wide field survey of the types planned for weak lensing and Type Ia SNe with SNAP are close to optimal for the optical detection of strong lenses. Such a ''piggy-back'' survey might be expected even pessimistically to provide a catalogue of a few thousand new strong lenses, with the numbers dominated by systems of faint blue galaxies lensed by foreground ellipticals. After sketching out our strategy for detecting and measuring these galaxy lenses using the SNAP images, we discuss some of the scientific applications of such a large sample of gravitational lenses: in particular we comment on the partition of information between lens structure, the source population properties and cosmology. Understanding this partitioning is key to assessing strong lens cosmography's value as a cosmological probe.

  19. Automated Fresnel lens tester system

    Energy Technology Data Exchange (ETDEWEB)

    Phipps, G.S.

    1981-07-01

    An automated data collection system controlled by a desktop computer has been developed for testing Fresnel concentrators (lenses) intended for solar energy applications. The system maps the two-dimensional irradiance pattern (image) formed in a plane parallel to the lens, whereas the lens and detector assembly track the sun. A point detector silicon diode (0.5-mm-dia active area) measures the irradiance at each point of an operator-defined rectilinear grid of data positions. Comparison with a second detector measuring solar insolation levels results in solar concentration ratios over the image plane. Summation of image plane energies allows calculation of lens efficiencies for various solar cell sizes. Various graphical plots of concentration ratio data help to visualize energy distribution patterns.

  20. Compliance among soft contact lens wearers.

    Science.gov (United States)

    Kuzman, Tomislav; Kutija, Marija Barisić; Masnec, Sanja; Jandroković, Sonja; Mrazovac, Danijela; Jurisić, Darija; Skegro, Ivan; Kalauz, Miro; Kordić, Rajko

    2014-12-01

    Contact lens compliance is proven to be crucial for preventing lens wear-related complications because of the interdependence of the steps in lens care regime and their influence on lens system microbial contamination. Awareness of the patients' lens handling compliance as well as correct recognition of non-compliant behaviours is the basis for creating more targeted strategies for patient education. The aim of this study was to investigate compliance among soft contact lens (SCL) wearers in different aspects of lens care handling and wearing habits. In our research 50 asymptomatic lens wearers filled out a questionnaire containing demographic data, lens type, hygiene and wearing habits, lenses and lens care system replacement schedule and self-evaluation of contact lens handling hygiene. We established criteria of compliance according to available manufacturer's recommendations, prior literature and our clinical experience. Only 2 (4%) of patients were fully compliant SCL wearers. The most common non-compliant behaviours were insufficient lens solution soaking time (62%), followed by failure to daily exchange lens case solution and showering while wearing lenses. 44% of patients reported storing lenses in saline solution. Mean lens storage case replacement was 3.6 months, with up to 78% patients replacing lens case at least once in 3 months. Average grade in self evaluating level of compliance was very good (4 +/- 0.78) (from 1-poor level of hygiene to 5-great level of hygiene). Lens wearers who reported excessive daily lens wear and more than 10 years of lens wearing experience were also found to be less compliant with other lens system care procedures. (t = -2.99, df=47, p lens system maintenance steps. Most common non-compliant behaviours were the ones that are crucial for maintaining lens sterility and preventing infection. Despite the low objective compliance rate, self grading was relatively high. Therefore, these results indicate the need for patient

  1. Curiosity's Mars Hand Lens Imager (MAHLI) Investigation

    Science.gov (United States)

    Edgett, Kenneth S.; Yingst, R. Aileen; Ravine, Michael A.; Caplinger, Michael A.; Maki, Justin N.; Ghaemi, F. Tony; Schaffner, Jacob A.; Bell, James F.; Edwards, Laurence J.; Herkenhoff, Kenneth E.; Heydari, Ezat; Kah, Linda C.; Lemmon, Mark T.; Minitti, Michelle E.; Olson, Timothy S.; Parker, Timothy J.; Rowland, Scott K.; Schieber, Juergen; Sullivan, Robert J.; Sumner, Dawn Y.; Thomas, Peter C.; Jensen, Elsa H.; Simmonds, John J.; Sengstacken, Aaron J.; Wilson, Reg G.; Goetz, Walter

    2012-01-01

    The Mars Science Laboratory (MSL) Mars Hand Lens Imager (MAHLI) investigation will use a 2-megapixel color camera with a focusable macro lens aboard the rover, Curiosity, to investigate the stratigraphy and grain-scale texture, structure, mineralogy, and morphology of geologic materials in northwestern Gale crater. Of particular interest is the stratigraphic record of a ?5 km thick layered rock sequence exposed on the slopes of Aeolis Mons (also known as Mount Sharp). The instrument consists of three parts, a camera head mounted on the turret at the end of a robotic arm, an electronics and data storage assembly located inside the rover body, and a calibration target mounted on the robotic arm shoulder azimuth actuator housing. MAHLI can acquire in-focus images at working distances from ?2.1 cm to infinity. At the minimum working distance, image pixel scale is ?14 μm per pixel and very coarse silt grains can be resolved. At the working distance of the Mars Exploration Rover Microscopic Imager cameras aboard Spirit and Opportunity, MAHLI?s resolution is comparable at ?30 μm per pixel. Onboard capabilities include autofocus, auto-exposure, sub-framing, video imaging, Bayer pattern color interpolation, lossy and lossless compression, focus merging of up to 8 focus stack images, white light and longwave ultraviolet (365 nm) illumination of nearby subjects, and 8 gigabytes of non-volatile memory data storage.

  2. Computer-aided lens assembly

    Science.gov (United States)

    Tomlinson, Richard; Alcock, Rob; Petzing, Jon; Coupland, Jeremy

    2004-01-01

    We propose a computer-aided method of lens manufacture that allows assembly, adjustment, and test phases to be run concurrently until an acceptable level of optical performance is reached. Misalignment of elements within a compound lens is determined by a comparison of the results of physical ray tracing by use of an array of Gaussian laser beams with numerically obtained geometric ray traces. An estimate of misalignment errors is made, and individual elements are adjusted in an iterative manner until performance criteria are achieved. The method is illustrated for the alignment of an air-spaced doublet.

  3. Status of the observed and predicted b anti-b production at the Tevatron

    Energy Technology Data Exchange (ETDEWEB)

    Happacher, F.; Giromini, P.; /Frascati; Ptohos, F.; /Cyprus U.

    2005-09-01

    The authors review the experimental status of the b-quark production at the Fermilab Tevatron. They compare all available measurements to perturbative QCD predictions (NLO and FONLL) and also to the parton-level cross section evaluated with parton-shower Monte Carlo generators. They examine both the single b cross section and the so called b{bar b} correlations. The review shows that the experimental situation is quite complicated because the measurements appear to be inconsistent among themselves. In this situation, there is no solid basis to either claim that perturbative QCD is challenged by these measurements or, in contrast, that long-standing discrepancies between data and theory have been resolved by incrementally improving the measurements and the theoretical prediction.

  4. Diffractive production of bb-bar in proton-antiproton collision at the Tevatron

    International Nuclear Information System (INIS)

    Alves, G.; Levin, E.

    1996-08-01

    We show that the cross section of the diffractive production of b b-bar can be described as the sum of two contributions: the first is proportional to the probability of finding a small size b b-bar color dipole in the fast hadron wave function before the interaction with a target, while the second is the b b-bar production after or during the interaction with the target. The formulae are presented as well as the discussion of the interrelation between these two contributions and the Ingelman-Schlein and coherent diffraction mechanisms. The main prediction is that the coherent diffraction mechanism dominates, at least at the Tevatron energies, giving the unique possibility to study it experimentally. (author). 25 refs., 10 figs

  5. NNLO QCD predictions for fully-differential top-quark pair production at the Tevatron

    Energy Technology Data Exchange (ETDEWEB)

    Czakon, Michał; Fiedler, Paul [Institut für Theoretische Teilchenphysik und Kosmologie,RWTH Aachen University, D-52056 Aachen (Germany); Heymes, David; Mitov, Alexander [Cavendish Laboratory, University of Cambridge,Cambridge CB3 0HE (United Kingdom)

    2016-05-05

    We present a comprehensive study of differential distributions for Tevatron top-pair events at the level of stable top quarks. All calculations are performed in NNLO QCD with the help of a fully differential partonic Monte-Carlo and are exact at this order in perturbation theory. We present predictions for all kinematic distributions for which data exists. Particular attention is paid on the top-quark forward-backward asymmetry which we study in detail. We compare the NNLO results with existing approximate NNLO predictions as well as differential distributions computed with different parton distribution sets. Theory errors are significantly smaller than current experimental ones with overall agreement between theory and data.

  6. Model-independent analysis of the Fermilab Tevatron turn-by-turn beam position monitor measurements

    Energy Technology Data Exchange (ETDEWEB)

    Petrenko, A.V.; /Novosibirsk, IYF; Valishev, A.A.; Lebedev, V.A.; /Fermilab

    2011-09-01

    Coherent transverse beam oscillations in the Tevatron were analyzed with the model-independent analysis (MIA) technique. This allowed one to obtain the model-independent values of coupled betatron amplitudes, phase advances, and dispersion function around the ring from a single dipole kick measurement. In order to solve the MIA mode mixing problem which limits the accuracy of determination of the optical functions, we have developed a new technique of rotational MIA mode untangling. The basic idea is to treat each beam position monitor (BPM) as two BPMs separated in a ring by exactly one turn. This leads to a simple criterion of MIA mode separation: the betatron phase advance between any BPM and its counterpart shifted by one turn should be equal to the betatron tune and therefore should not depend on the BPM position in the ring. Furthermore, we describe a MIA-based technique to locate vibrating magnets in a storage ring.

  7. Single top quarks at the Tevatron and observation of the s-channel production mode

    CERN Multimedia

    CERN. Geneva

    2014-01-01

    The presentation gives an overview of single-top-quark production at the Tevatron proton-antiproton collider. The talk covers measurements of the total s+t channel production cross section and the extraction of the CKM matrix element |V_tb|. Furthermore, separate analyses of the s-channel and t-channel production modes are discussed. The data correspond to total integrated luminosities of up to 9.7 fb-1 per experiment and represent in most cases the full Run-II dataset. Through a combination of the CDF and D0 measurements the first observation of single-top-quark production in the s-channel is claimed. This is particularly highlighted in the seminar.

  8. Top anti-top Asymmetries at the Tevatron and the LHC

    Energy Technology Data Exchange (ETDEWEB)

    Peters, Yvonne Reinhild [DESY

    2012-11-01

    The heaviest known elementary particle today, the top quark, has been discovered in 1995 by the CDF and D0 collaborations at the Tevatron proton antiproton collider at Fermilab. Recently, the CDF and D0 collaborations have studied the forward-backward asymmetry in ttbar events, resulting in measured values larger than the standard model prediction. With the start of the LHC at CERN in 2010, a new top quark factory has opened and asymmetry measurements in ttbar have also been performed in a proton proton environment with higher collision energy. No deviations from the standard model have been noticed so far in the measurements of ATLAS and CMS. This article discusses recent results of asymmetry measurements in ttbar events of the ATLAS, CDF, CMS and D0 collaborations.

  9. Combined Forward-Backward Asymmetry Measurements in Top-Antitop Quark Production at the Tevatron

    Science.gov (United States)

    Aaltonen, T.; Abazov, V. M.; Abbott, B.; Acharya, B. S.; Adams, M.; Adams, T.; Agnew, J. P.; Alexeev, G. D.; Alkhazov, G.; Alton, A.; Amerio, S.; Amidei, D.; Anastassov, A.; Annovi, A.; Antos, J.; Apollinari, G.; Appel, J. A.; Arisawa, T.; Artikov, A.; Asaadi, J.; Ashmanskas, W.; Askew, A.; Atkins, S.; Auerbach, B.; Augsten, K.; Aurisano, A.; Aushev, V.; Aushev, Y.; Avila, C.; Azfar, F.; Badaud, F.; Badgett, W.; Bae, T.; Bagby, L.; Baldin, B.; Bandurin, D. V.; Banerjee, S.; Barbaro-Galtieri, A.; Barberis, E.; Baringer, P.; Barnes, V. E.; Barnett, B. A.; Barria, P.; Bartlett, J. F.; Bartos, P.; Bassler, U.; Bauce, M.; Bazterra, V.; Bean, A.; Bedeschi, F.; Begalli, M.; Behari, S.; Bellantoni, L.; Bellettini, G.; Bellinger, J.; Benjamin, D.; Beretvas, A.; Beri, S. B.; Bernardi, G.; Bernhard, R.; Bertram, I.; Besançon, M.; Beuselinck, R.; Bhat, P. C.; Bhatia, S.; Bhatnagar, V.; Bhatti, A.; Bland, K. R.; Blazey, G.; Blessing, S.; Bloom, K.; Blumenfeld, B.; Bocci, A.; Bodek, A.; Boehnlein, A.; Boline, D.; Boos, E. E.; Borissov, G.; Bortoletto, D.; Borysova, M.; Boudreau, J.; Boveia, A.; Brandt, A.; Brandt, O.; Brigliadori, L.; Brochmann, M.; Brock, R.; Bromberg, C.; Bross, A.; Brown, D.; Brucken, E.; Bu, X. B.; Budagov, J.; Budd, H. S.; Buehler, M.; Buescher, V.; Bunichev, V.; Burdin, S.; Burkett, K.; Busetto, G.; Bussey, P.; Buszello, C. P.; Butti, P.; Buzatu, A.; Calamba, A.; Camacho-Pérez, E.; Camarda, S.; Campanelli, M.; Canelli, F.; Carls, B.; Carlsmith, D.; Carosi, R.; Carrillo, S.; Casal, B.; Casarsa, M.; Casey, B. C. K.; Castilla-Valdez, H.; Castro, A.; Catastini, P.; Caughron, S.; Cauz, D.; Cavaliere, V.; Cerri, A.; Cerrito, L.; Chakrabarti, S.; Chan, K. M.; Chandra, A.; Chapelain, A.; Chapon, E.; Chen, G.; Chen, Y. C.; Chertok, M.; Chiarelli, G.; Chlachidze, G.; Cho, K.; Cho, S. W.; Choi, S.; Chokheli, D.; Choudhary, B.; Cihangir, S.; Claes, D.; Clark, A.; Clarke, C.; Clutter, J.; Convery, M. E.; Conway, J.; Cooke, M.; Cooper, W. E.; Corbo, M.; Corcoran, M.; Cordelli, M.; Couderc, F.; Cousinou, M.-C.; Cox, C. A.; Cox, D. J.; Cremonesi, M.; Cruz, D.; Cuevas, J.; Culbertson, R.; Cuth, J.; Cutts, D.; Das, A.; d'Ascenzo, N.; Datta, M.; Davies, G.; de Barbaro, P.; de Jong, S. J.; De La Cruz-Burelo, E.; Déliot, F.; Demina, R.; Demortier, L.; Deninno, M.; Denisov, D.; Denisov, S. P.; D'Errico, M.; Desai, S.; Deterre, C.; DeVaughan, K.; Devoto, F.; Di Canto, A.; Di Ruzza, B.; Diehl, H. T.; Diesburg, M.; Ding, P. F.; Dittmann, J. R.; Dominguez, A.; Donati, S.; D'Onofrio, M.; Dorigo, M.; Driutti, A.; Drutskoy, A.; Dubey, A.; Dudko, L. V.; Duperrin, A.; Dutt, S.; Eads, M.; Ebina, K.; Edgar, R.; Edmunds, D.; Elagin, A.; Ellison, J.; Elvira, V. D.; Enari, Y.; Erbacher, R.; Errede, S.; Esham, B.; Evans, H.; Evdokimov, A.; Evdokimov, V. N.; Farrington, S.; Fauré, A.; Feng, L.; Ferbel, T.; Fernández Ramos, J. P.; Fiedler, F.; Field, R.; Filthaut, F.; Fisher, W.; Fisk, H. E.; Flanagan, G.; Forrest, R.; Fortner, M.; Fox, H.; Franc, J.; Franklin, M.; Freeman, J. C.; Frisch, H.; Fuess, S.; Funakoshi, Y.; Galloni, C.; Garbincius, P. H.; Garcia-Bellido, A.; García-González, J. A.; Garfinkel, A. F.; Garosi, P.; Gavrilov, V.; Geng, W.; Gerber, C. E.; Gerberich, H.; Gerchtein, E.; Gershtein, Y.; Giagu, S.; Giakoumopoulou, V.; Gibson, K.; Ginsburg, C. M.; Ginther, G.; Giokaris, N.; Giromini, P.; Glagolev, V.; Glenzinski, D.; Gogota, O.; Gold, M.; Goldin, D.; Golossanov, A.; Golovanov, G.; Gomez, G.; Gomez-Ceballos, G.; Goncharov, M.; González López, O.; Gorelov, I.; Goshaw, A. T.; Goulianos, K.; Gramellini, E.; Grannis, P. D.; Greder, S.; Greenlee, H.; Grenier, G.; Gris, Ph.; Grivaz, J.-F.; Grohsjean, A.; Grosso-Pilcher, C.; Grünendahl, S.; Grünewald, M. W.; Guillemin, T.; Guimaraes da Costa, J.; Gutierrez, G.; Gutierrez, P.; Hahn, S. R.; Haley, J.; Han, J. Y.; Han, L.; Happacher, F.; Hara, K.; Harder, K.; Hare, M.; Harel, A.; Harr, R. F.; Harrington-Taber, T.; Hatakeyama, K.; Hauptman, J. M.; Hays, C.; Hays, J.; Head, T.; Hebbeker, T.; Hedin, D.; Hegab, H.; Heinrich, J.; Heinson, A. P.; Heintz, U.; Hensel, C.; Heredia-De La Cruz, I.; Herndon, M.; Herner, K.; Hesketh, G.; Hildreth, M. D.; Hirosky, R.; Hoang, T.; Hobbs, J. D.; Hocker, A.; Hoeneisen, B.; Hogan, J.; Hohlfeld, M.; Holzbauer, J. L.; Hong, Z.; Hopkins, W.; Hou, S.; Howley, I.; Hubacek, Z.; Hughes, R. E.; Husemann, U.; Hussein, M.; Huston, J.; Hynek, V.; Iashvili, I.; Ilchenko, Y.; Illingworth, R.; Introzzi, G.; Iori, M.; Ito, A. S.; Ivanov, A.; Jabeen, S.; Jaffré, M.; James, E.; Jang, D.; Jayasinghe, A.; Jayatilaka, B.; Jeon, E. J.; Jeong, M. S.; Jesik, R.; Jiang, P.; Jindariani, S.; Johns, K.; Johnson, E.; Johnson, M.; Jonckheere, A.; Jones, M.; Jonsson, P.; Joo, K. K.; Joshi, J.; Jun, S. Y.; Jung, A. W.; Junk, T. R.; Juste, A.; Kajfasz, E.; Kambeitz, M.; Kamon, T.; Karchin, P. E.; Karmanov, D.; Kasmi, A.; Kato, Y.; Katsanos, I.; Kaur, M.; Kehoe, R.; Kermiche, S.; Ketchum, W.; Keung, J.; Khalatyan, N.; Khanov, A.; Kharchilava, A.; Kharzheev, Y. N.; Kilminster, B.; Kim, D. H.; Kim, H. S.; Kim, J. E.; Kim, M. J.; Kim, S. H.; Kim, S. B.; Kim, Y. J.; Kim, Y. K.; Kimura, N.; Kirby, M.; Kiselevich, I.; Kohli, J. M.; Kondo, K.; Kong, D. J.; Konigsberg, J.; Kotwal, A. V.; Kozelov, A. V.; Kraus, J.; Kreps, M.; Kroll, J.; Kruse, M.; Kuhr, T.; Kumar, A.; Kupco, A.; Kurata, M.; Kurča, T.; Kuzmin, V. A.; Laasanen, A. T.; Lammel, S.; Lammers, S.; Lancaster, M.; Lannon, K.; Latino, G.; Lebrun, P.; Lee, H. S.; Lee, H. S.; Lee, J. S.; Lee, S. W.; Lee, W. M.; Lei, X.; Lellouch, J.; Leo, S.; Leone, S.; Lewis, J. D.; Li, D.; Li, H.; Li, L.; Li, Q. Z.; Lim, J. K.; Limosani, A.; Lincoln, D.; Linnemann, J.; Lipaev, V. V.; Lipeles, E.; Lipton, R.; Lister, A.; Liu, H.; Liu, Q.; Liu, T.; Liu, Y.; Lobodenko, A.; Lockwitz, S.; Loginov, A.; Lokajicek, M.; Lopes de Sa, R.; Lucchesi, D.; Lucà, A.; Lueck, J.; Lujan, P.; Lukens, P.; Luna-Garcia, R.; Lungu, G.; Lyon, A. L.; Lys, J.; Lysak, R.; Maciel, A. K. A.; Madar, R.; Madrak, R.; Maestro, P.; Magaña-Villalba, R.; Malik, S.; Malik, S.; Malyshev, V. L.; Manca, G.; Manousakis-Katsikakis, A.; Mansour, J.; Marchese, L.; Margaroli, F.; Marino, P.; Martínez-Ortega, J.; Matera, K.; Mattson, M. E.; Mazzacane, A.; Mazzanti, P.; McCarthy, R.; McGivern, C. L.; McNulty, R.; Mehta, A.; Mehtala, P.; Meijer, M. M.; Melnitchouk, A.; Menezes, D.; Mercadante, P. G.; Merkin, M.; Mesropian, C.; Meyer, A.; Meyer, J.; Miao, T.; Miconi, F.; Mietlicki, D.; Mitra, A.; Miyake, H.; Moed, S.; Moggi, N.; Mondal, N. K.; Moon, C. S.; Moore, R.; Morello, M. J.; Mukherjee, A.; Mulhearn, M.; Muller, Th.; Murat, P.; Mussini, M.; Nachtman, J.; Nagai, Y.; Naganoma, J.; Nagy, E.; Nakano, I.; Napier, A.; Narain, M.; Nayyar, R.; Neal, H. A.; Negret, J. P.; Nett, J.; Neustroev, P.; Nguyen, H. T.; Nigmanov, T.; Nodulman, L.; Noh, S. Y.; Norniella, O.; Nunnemann, T.; Oakes, L.; Oh, S. H.; Oh, Y. D.; Okusawa, T.; Orava, R.; Orduna, J.; Ortolan, L.; Osman, N.; Pagliarone, C.; Pal, A.; Palencia, E.; Palni, P.; Papadimitriou, V.; Parashar, N.; Parihar, V.; Park, S. K.; Parker, W.; Partridge, R.; Parua, N.; Patwa, A.; Pauletta, G.; Paulini, M.; Paus, C.; Penning, B.; Perfilov, M.; Peters, Y.; Petridis, K.; Petrillo, G.; Pétroff, P.; Phillips, T. J.; Piacentino, G.; Pianori, E.; Pilot, J.; Pitts, K.; Plager, C.; Pleier, M.-A.; Podstavkov, V. M.; Pondrom, L.; Popov, A. V.; Poprocki, S.; Potamianos, K.; Pranko, A.; Prewitt, M.; Price, D.; Prokopenko, N.; Prokoshin, F.; Ptohos, F.; Punzi, G.; Qian, J.; Quadt, A.; Quinn, B.; Ratoff, P. N.; Razumov, I.; Redondo Fernández, I.; Renton, P.; Rescigno, M.; Rimondi, F.; Ripp-Baudot, I.; Ristori, L.; Rizatdinova, F.; Robson, A.; Rodriguez, T.; Rolli, S.; Rominsky, M.; Ronzani, M.; Roser, R.; Rosner, J. L.; Ross, A.; Royon, C.; Rubinov, P.; Ruchti, R.; Ruffini, F.; Ruiz, A.; Russ, J.; Rusu, V.; Sajot, G.; Sakumoto, W. K.; Sakurai, Y.; Sánchez-Hernández, A.; Sanders, M. P.; Santi, L.; Santos, A. S.; Sato, K.; Savage, G.; Saveliev, V.; Savitskyi, M.; Savoy-Navarro, A.; Sawyer, L.; Scanlon, T.; Schamberger, R. D.; Scheglov, Y.; Schellman, H.; Schlabach, P.; Schmidt, E. E.; Schott, M.; Schwanenberger, C.; Schwarz, T.; Schwienhorst, R.; Scodellaro, L.; Scuri, F.; Seidel, S.; Seiya, Y.; Sekaric, J.; Semenov, A.; Severini, H.; Sforza, F.; Shabalina, E.; Shalhout, S. Z.; Shary, V.; Shaw, S.; Shchukin, A. A.; Shears, T.; Shepard, P. F.; Shimojima, M.; Shkola, O.; Shochet, M.; Shreyber-Tecker, I.; Simak, V.; Simonenko, A.; Skubic, P.; Slattery, P.; Sliwa, K.; Smith, J. R.; Snider, F. D.; Snow, G. R.; Snow, J.; Snyder, S.; Söldner-Rembold, S.; Song, H.; Sonnenschein, L.; Sorin, V.; Soustruznik, K.; St. Denis, R.; Stancari, M.; Stark, J.; Stefaniuk, N.; Stentz, D.; Stoyanova, D. A.; Strauss, M.; Strologas, J.; Sudo, Y.; Sukhanov, A.; Suslov, I.; Suter, L.; Svoisky, P.; Takemasa, K.; Takeuchi, Y.; Tang, J.; Tecchio, M.; Teng, P. K.; Thom, J.; Thomson, E.; Thukral, V.; Titov, M.; Toback, D.; Tokar, S.; Tokmenin, V. V.; Tollefson, K.; Tomura, T.; Tonelli, D.; Torre, S.; Torretta, D.; Totaro, P.; Trovato, M.; Tsai, Y.-T.; Tsybychev, D.; Tuchming, B.; Tully, C.; Ukegawa, F.; Uozumi, S.; Uvarov, L.; Uvarov, S.; Uzunyan, S.; Van Kooten, R.; van Leeuwen, W. M.; Varelas, N.; Varnes, E. W.; Vasilyev, I. A.; Vázquez, F.; Velev, G.; Vellidis, C.; Verkheev, A. Y.; Vernieri, C.; Vertogradov, L. S.; Verzocchi, M.; Vesterinen, M.; Vidal, M.; Vilanova, D.; Vilar, R.; Vizán, J.; Vogel, M.; Vokac, P.; Volpi, G.; Wagner, P.; Wahl, H. D.; Wallny, R.; Wang, M. H. L. S.; Wang, S. M.; Warchol, J.; Waters, D.; Watts, G.; Wayne, M.; Weichert, J.; Welty-Rieger, L.; Wester, W. C.; Whiteson, D.; Wicklund, A. B.; Wilbur, S.; Williams, H. H.; Williams, M. R. J.; Wilson, G. W.; Wilson, J. S.; Wilson, P.; Winer, B. L.; Wittich, P.; Wobisch, M.; Wolbers, S.; Wolfmeister, H.; Wood, D. R.; Wright, T.; Wu, X.; Wu, Z.; Wyatt, T. R.; Xie, Y.; Yamada, R.; Yamamoto, K.; Yamato, D.; Yang, S.; Yang, T.; Yang, U. K.; Yang, Y. C.; Yao, W.-M.; Yasuda, T.; Yatsunenko, Y. A.; Ye, W.; Ye, Z.; Yeh, G. P.; Yi, K.; Yin, H.; Yip, K.; Yoh, J.; Yorita, K.; Yoshida, T.; Youn, S. W.; Yu, G. B.; Yu, I.; Yu, J. M.; Zanetti, A. M.; Zeng, Y.; Zennamo, J.; Zhao, T. G.; Zhou, B.; Zhou, C.; Zhu, J.; Zielinski, M.; Zieminska, D.; Zivkovic, L.; Zucchelli, S.; CDF Collaboration

    2018-01-01

    The CDF and D0 experiments at the Fermilab Tevatron have measured the asymmetry between yields of forward- and backward-produced top and antitop quarks based on their rapidity difference and the asymmetry between their decay leptons. These measurements use the full data sets collected in proton-antiproton collisions at a center-of-mass energy of √{s }=1.96 TeV . We report the results of combinations of the inclusive asymmetries and their differential dependencies on relevant kinematic quantities. The combined inclusive asymmetry is AFBt t ¯=0.128 ±0.025 . The combined inclusive and differential asymmetries are consistent with recent standard model predictions.

  10. B^0_s and lambda^0_b lifetimes and branching ratios at the Tevatron

    Energy Technology Data Exchange (ETDEWEB)

    Behari, S.; /Johns Hopkins U.

    2006-12-01

    The authors review B{sub s}{sup 0} and {Lambda}{sub b}{sup 0} lifetime and branching ratio measurements from the CDF and D0 experiments at the Tevatron Run II. Using up to 1 fb{sup -1} data samples per experiment, {Lambda}{sub b}{sup 0} lifetime in J/{Psi}{Lambda}{sup 0} decays, B{sub s}{sup 0} lifetime difference in K{sup +}K{sup -} and D{sub s}{sup (*)+} D{sub s}{sup (*)-} decays and B{sub s}{sup 0} branching ratio in D{sub s1}{sup -}(2536){mu}{sup +} {nu}X decays are reported.

  11. Digitral Down Conversion Technology for Tevatron Beam Line Tuner at FNAL

    Energy Technology Data Exchange (ETDEWEB)

    Schappert, W.; Lorman, E.; Scarpine, V.; Ross, M.C.; Sebek, J.; Straumann, T.; /Fermilab /SLAC

    2008-03-17

    Fermilab is presently in Run II collider operations and is developing instrumentation to improve luminosity. Improving the orbit matching between accelerator components using a Beam Line Tuner (BLT) can improve the luminosity. Digital Down Conversion (DDC) has been proposed as a method for making more accurate beam position measurements. Fermilab has implemented a BLT system using a DDC technique to measure orbit oscillations during injections from the Main Injector to the Tevatron. The output of a fast ADC is downconverted and filtered in software. The system measures the x and y positions, the intensity, and the time of arrival for each proton or antiproton bunch, on a turn-by-turn basis, during the first 1024 turns immediately following injection. We present results showing position, intensity, and time of arrival for both injected and coasting beam. Initial results indicate a position resolution of {approx}20 to 40 microns and a phase resolution of {approx}25 ps.

  12. Digital Down Conversion Technology for Tevatron Beam Line Tuner at FNAL

    International Nuclear Information System (INIS)

    Schappert, W.; Lorman, E.; Scarpine, V.; Ross, M.C.; Sebek, J.; Straumann, T.

    2008-01-01

    Fermilab is presently in Run II collider operations and is developing instrumentation to improve luminosity. Improving the orbit matching between accelerator components using a Beam Line Tuner (BLT) can improve the luminosity. Digital Down Conversion (DDC) has been proposed as a method for making more accurate beam position measurements. Fermilab has implemented a BLT system using a DDC technique to measure orbit oscillations during injections from the Main Injector to the Tevatron. The output of a fast ADC is downconverted and filtered in software. The system measures the x and y positions, the intensity, and the time of arrival for each proton or antiproton bunch, on a turn-by-turn basis, during the first 1024 turns immediately following injection. We present results showing position, intensity, and time of arrival for both injected and coasting beam. Initial results indicate a position resolution of ∼20 to 40 microns and a phase resolution of ∼25 ps

  13. Search for the Higgs-Boson with the CDF experiment at Tevatron

    Energy Technology Data Exchange (ETDEWEB)

    Hennecke, Martin [Univ. of Karlsruhe (Germany)

    2005-06-10

    A search for a low-mass SM Higgs-Boson in the channel WH → lvb$\\bar{b}$ has been performed using neural networks. The data were taken by the CDF experiment at the p-$\\bar{p}$ collider Tevatron from 2000-2003, corresponding to in integrated luminosity of Lint = 162 pb-1 at a CMS-energy of √s = 1.96 TeV. 95% confidence level upper limits are set on σ × BR, the product of the production cross section times the Branching ratio, as a function of the Higgs boson mass. Cross sections above 8 pb are excluded for six different Higgs masses between 110 GeV/c2 and 150 GeV/c2. The required integrated luminosities for a 95% C.L. exclusion, 3σ evidence and 5σ discovery are calculated.

  14. Acanthamoeba keratitis. Contact lens and noncontact lens characteristics.

    Science.gov (United States)

    Chynn, E W; Lopez, M A; Pavan-Langston, D; Talamo, J H

    1995-09-01

    To identify potential differences in time to diagnosis and final visual outcome between contact lens and noncontact lens users with Acanthamoeba keratitis. Prior studies have shown early diagnosis and therapy to be related to outcome but have not analyzed differences among patients with and without contact lenses. A retrospective analysis of 11 consecutive cases (involving 13 eyes) of Acanthamoeba keratitis diagnosed at one institution over a 3-year period. Mean time to diagnosis was significantly longer in noncontact lens users versus those who wore contact lenses (mean, 5.8 versus 3.3 weeks). Fifty percent of patients who did not wear contact lenses had a poor outcome (visual acuity worse than 20/40 or penetrating keratoplasty) versus 14% of patients who wore contact lenses. Diagnoses were made later in patients without contact lenses, and these patients had a worse visual outcome than those with Acanthamoeba keratitis who wore contact lenses. All patients with unresponsive microbial keratitis, even those without contact lens use, should be evaluated for Acanthamoeba.

  15. Search for the Standard Model Higgs Boson associated with a W Boson using Matrix Element Technique in the CDF detector at the Tevatron

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez, Barbara Alvarez [Univ. of Oviedo (Spain)

    2010-05-01

    In this thesis a direct search for the Standard Model Higgs boson production in association with a W boson at the CDF detector in the Tevatron is presented. This search contributes predominantly in the region of low mass Higgs region, when the mass of Higgs boson is less than about 135 GeV. The search is performed in a final state where the Higgs boson decays into two b quarks, and the W boson decays leptonically, to a charged lepton (it can be an electron or a muon) and a neutrino. This work is organized as follows. Chapter 2 gives an overview of the Standard Model theory of particle physics and presents the SM Higgs boson search results at LEP, and the Tevatron colliders, as well as the prospects for the SM Higgs boson searches at the LHC. The dataset used in this analysis corresponds to 4.8 fb-1 of integrated luminosity of p$\\bar{p}$ collisions at a center of mass energy of 1.96 TeV. That is the luminosity acquired between the beginning of the CDF Run II experiment, February 2002, and May 2009. The relevant aspects, for this analysis, of the Tevatron accelerator and the CDF detector are shown in Chapter 3. In Chapter 4 the particles and observables that make up the WH final state, electrons, muons, ET, and jets are presented. The CDF standard b-tagging algorithms to identify b jets, and the neural network flavor separator to distinguish them from other flavor jets are also described in Chapter 4. The main background contributions are those coming from heavy flavor production processes, such as those coming from Wbb, Wcc or Wc and tt. The signal and background signatures are discussed in Chapter 5 together with the Monte CArlo generators that have been used to simulate almost all the events used in this thesis. WH candidate events have a high-pT lepton (electron or muon), high missing transverse energy, and two or more than two jets in the final state. Chapter 6 describes the event selection applied in this analysis and the

  16. Conceptual design of hollow electron lenses for beam halo control in the Large Hadron Collider

    Energy Technology Data Exchange (ETDEWEB)

    Stancari, Giulio [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Previtali, Valentina [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Valishev, Alexander [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Bruce, Roderik [European Organization for Nuclear Research (CERN), Geneva (Switzerland); Redaelli, Stefano [European Organization for Nuclear Research (CERN), Geneva (Switzerland); Rossi, Adriana [European Organization for Nuclear Research (CERN), Geneva (Switzerland); Salvachua Ferrando, Belen [European Organization for Nuclear Research (CERN), Geneva (Switzerland)

    2014-06-26

    Collimation with hollow electron beams is a technique for halo control in high-power hadron beams. It is based on an electron beam (possibly pulsed or modulated in intensity) guided by strong axial magnetic fields which overlaps with the circulating beam in a short section of the ring. The concept was tested experimentally at the Fermilab Tevatron collider using a hollow electron gun installed in one of the Tevatron electron lenses. We are proposing a conceptual design for applying this technique to the Large Hadron Collider at CERN. A prototype hollow electron gun for the LHC was built and tested. The expected performance of the hollow electron beam collimator was based on Tevatron experiments and on numerical tracking simulations. Halo removal rates and enhancements of halo diffusivity were estimated as a function of beam and lattice parameters. Proton beam core lifetimes and emittance growth rates were checked to ensure that undesired effects were suppressed. Hardware specifications were based on the Tevatron devices and on preliminary engineering integration studies in the LHC machine. Required resources and a possible timeline were also outlined, together with a brief discussion of alternative halo-removal schemes and of other possible uses of electron lenses to improve the performance of the LHC.

  17. A microcapillary lens for X-rays

    CERN Document Server

    Dudchik, Y I

    1999-01-01

    A new design of a compound refractive lens for X-rays is proposed. The lens is made as a set of glue microlenses placed in a glass capillary. The technique of lens fabrication is described. Results of ray tracing calculations for 8 and 15 keV photons are represented.

  18. The Ultrawideband Leaky Lens Antenna

    NARCIS (Netherlands)

    Bruni, S.; Neto, A.; Marliani, F.

    2007-01-01

    A novel directive and nondispersive antenna is presented: the ultrawideband (UWB) leaky lens. It is based on the broad band Cherenkov radiation occurring at a slot printed between different infinite homogeneous dielectrics. The first part of the paper presents the antenna concept and the UWB design.

  19. ECTOPIC LENS EXTRACTION IN CHILDREN

    Directory of Open Access Journals (Sweden)

    Vladimir Pfeifer

    2002-12-01

    Full Text Available Background. Ectopia lentis continues to be a therapeutic challenge for ophthalmologists. It can occur as an isolated condition, after ocular trauma, in association with other ocular disorders, as part of a systemic mesodermal disease or a complication of general metabolic disorders. Minimal subluxation of the lens may cause no visual symptoms, but in more advanced cases serious optical disturbances arise. The most important is amblyopia. Surgical treatment options include iris manipulation, lens discission, aspiration, intracapsular or extracapsular extraction, and pars plana lensectomy. The choice of surgical technique remains controversial, in part because of the historically poor visual results and high rate of perioperative complications, including vitreous loss and retinal detachment.Methods. We describe a surgical technique based on the use of the Cionni endocapsular tension ring, dry irrigation aspiration of lens material, centration of the capsular bag and foldable intraocular lens implantation into the bag. With mentioned surgical technique 8 patients were operated; 4 boys and 4 girls, together 11 eyes.Results. The final BCVA after follow up period improved in 9 eyes and it remained the same as before operation in one eye. Statistical comparison of preoperative and postoperative visual acuities showed significant improvement. On the other hand there was no correlation between preoperative and postoperative visual acuity.Conclusions. This surgical procedure is an alternative approach in solving this challenging cases of ectopia lentis with good postoperative visual rehabilitation.

  20. Spinning pipe gas lens revisited

    CSIR Research Space (South Africa)

    Mafusire, C

    2008-01-01

    Full Text Available , there is little information on optical phase aberrations and no study to date on the propagation parameters of the laser beam, but has rather remained rooted in the domain of ray optics. Researchers revisit the spinning pipe gas lens in this paper with new...

  1. Tube entrance lens focus control

    Science.gov (United States)

    Weisser, D. C.; Fifield, L. K.; Kitchen, T. F. G.; Tunningley, T. B.; Lobanov, N. R.; Muirhead, A. G.

    2013-02-01

    The entrance of the accelerator tube in a large electrostatic accelerator imposes a strong lens that dominates the beam optics. The magnification of the lens is large because of the low injection energy, the high voltage gradient of the acceleration tube and the long distance to the terminal. In the absence of the acceleration, the magnification would produce an unacceptably large beam spot at the terminal. The tyranny of the lens is especially irksome when the accelerator is required to operate at a lower terminal voltage than the one corresponding to the nominal gradient at high voltage. One way around the difficulty, used in NEC Pelletron accelerators, is to insert a series of nylon and steel rods that short together units of the acceleration structure at the terminal leaving the ones near the entrance close to the nominal gradient for optimum transmission. This operation takes time and risks the loss of insulating gas. Another alternative used in the 25URC at Oak Ridge National Laboratory, is to focus the beam at the tube entrance, substantially diluting the effect of the entrance lens. The beam then diverges and so requires an additional lens part way to the terminal. This solution is only partially effective and still necessitates use of shorting rods for low voltage operation. The fact that these elaborate strategies are used is evidence that the alternative of lowering the injection energy as the terminal voltage is lowered imposes enough problems that it is not used in practice. We have modeled a solution that controls the voltage gradient at the tube entrance using an external power supply. This not only maintains the focusing effect of the lens but provides the opportunity to tune the beam by adjusting the entrance lens. A 150 kV power supply outside the pressure vessel feeds a controllable voltage through a high voltage feed-through to the fifth electrode of the accelerator tube. Thus 150 kV on this electrode creates the nominal gradient of 30 kV per

  2. Lens stem cells may reside outside the lens capsule: an hypothesis

    Directory of Open Access Journals (Sweden)

    Meyer Rita A

    2007-06-01

    Full Text Available Abstract In this paper, we consider the ocular lens in the context of contemporary developments in biological ideas. We attempt to reconcile lens biology with stem cell concepts and a dearth of lens tumors. Historically, the lens has been viewed as a closed system, in which cells at the periphery of the lens epithelium differentiate into fiber cells. Theoretical considerations led us to question whether the intracapsular lens is indeed self-contained. Since stem cells generate tumors and the lens does not naturally develop tumors, we reasoned that lens stem cells may not be present within the capsule. We hypothesize that lens stem cells reside outside the lens capsule, in the nearby ciliary body. Our ideas challenge the existing lens biology paradigm. We begin our discussion with lens background information, in order to describe our lens stem cell hypothesis in the context of published data. Then we present the ciliary body as a possible source for lens stem cells, and conclude by comparing the ocular lens with the corneal epithelium.

  3. Fabrication of polycrystalline diamond refractive X-ray lens by femtosecond laser processing

    Energy Technology Data Exchange (ETDEWEB)

    Kononenko, T.V.; Ralchenko, V.G.; Ashkinazi, E.E.; Konov, V.I. [General Physics Institute of Russian Academy of Sciences, Moscow (Russian Federation); National Research Nuclear University ' ' MEPhI' ' , Moscow (Russian Federation); Polikarpov, M.; Ershov, P. [Immanuel Kant Baltic Federal University, Functional Nanomaterials, Kaliningrad (Russian Federation); Kuznetsov, S.; Yunkin, V. [Institute of Microelectronics Technology RAS, Chernogolovka, Moscow region (Russian Federation); Snigireva, I. [European Synchrotron Radiation Facility, Grenoble (France)

    2016-03-15

    X-ray planar compound refractive lenses were fabricated from a polycrystalline diamond plate grown by chemical vapor deposition, by precise through cutting with femtosecond laser pulses. The lens geometry and the surface morphology were investigated with optical and scanning electron microscopy, while the material structure modification was analyzed by Raman spectroscopy. The results of the preliminary lens test at 9.25-keV X-rays are presented. (orig.)

  4. Fabrication of polycrystalline diamond refractive X-ray lens by femtosecond laser processing

    International Nuclear Information System (INIS)

    Kononenko, T.V.; Ralchenko, V.G.; Ashkinazi, E.E.; Konov, V.I.; Polikarpov, M.; Ershov, P.; Kuznetsov, S.; Yunkin, V.; Snigireva, I.

    2016-01-01

    X-ray planar compound refractive lenses were fabricated from a polycrystalline diamond plate grown by chemical vapor deposition, by precise through cutting with femtosecond laser pulses. The lens geometry and the surface morphology were investigated with optical and scanning electron microscopy, while the material structure modification was analyzed by Raman spectroscopy. The results of the preliminary lens test at 9.25-keV X-rays are presented. (orig.)

  5. Modern lens antennas for communications engineering

    CERN Document Server

    Thornton, John

    2012-01-01

    The aim of this book is to present the modern design principles and analysis of lens antennas. It gives graduates and RF/Microwave professionals the design insights in order to make full use of lens antennas.  Why do we want to write a book in lens antennas? Because this topic has not been thoroughly publicized, its importance is underestimated. As antennas play a key role in communication systems, recent development in wireless communications would indeed benefit from the characteristics of lens antennas: low profile, and low cost etc.  The major advantages of lens antennas are na

  6. Lens decenter and tilt measurement by interferogram

    Science.gov (United States)

    Hung, Min-Wei; Wu, Wen-Hong; Huang, Kuo-Cheng

    2009-11-01

    For the recent years, the vigorous development of the electro-optic industry, particularly the digital camera and the cellular phone camera, has placed a larger and larger demand for the optical devices. Among the optical lens, the aspherical optical lens plays the key component because the aspherical lens may provide better imaging quality then the spherical lens does. For the manufacturing reason, the aspherical lens is prone to a decenter or tilt issue with respect to the optical axes of its two surfaces. To measure decenter and tile error specifically would help to obviate the deficient lens, but most of the present measuring method can't provide this function. This paper proposed a new method to specifically measure the decenter and tile of lens by observing the interferogram of each surface. And the corresponding measuring instrument, which contains interferometer and motion stages, was introduced as well.

  7. Searches for the Standard Model Higgs boson at the Tevatron collider

    Energy Technology Data Exchange (ETDEWEB)

    Fisher, Wade C. [Michigan State Univ., East Lansing, MI (United States). Dept. of Physics and Astronomy; Junk, Thomas R. [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)

    2016-01-01

    During Run II of the Tevatron collider, which took place from 2001 until 2011, the CDF and D0 detectors each collected approximately 10 fb -1 of collision data at a center-of-mass energy of . This dataset allowed for tests for the presence of the SM Higgs boson in the mass range 90-200 GeV in the production modes gg → H, W/ZH, vector-boson fusion, and H, with H decay modes H → , H → W+W-, H →

  8. Top-squark mixing effects in the supersymmetric electroweak corrections to top-quark production at the Fermilab Tevatron

    International Nuclear Information System (INIS)

    Yang, J.M.; Li, C.S.

    1996-01-01

    Taking into account the mixing effects between left- and right-handed top squarks, we calculate the genuine supersymmetric electroweak correction to top-quark production at the Fermilab Tevatron in the minimal supersymmetric model. The analytic expressions of the corrections to both the parton level cross section and the total hadronic cross section are presented. Some numerical examples are also given to show the size of the corrections. copyright 1996 The American Physical Society

  9. Search for anomalous couplings in WW and WZ measurements at the Tevatron (D0 and CDF results)

    International Nuclear Information System (INIS)

    Diehl, H.T.

    1995-06-01

    The search for WW and WZ production in p anti p collisions at √s = 1.8 TeV using the CDF and D0 detectors is presented. Three analyses, one concentrating on the leptons + jets decay channels and two concentrating on the dilepton decay channels are described in detail. Limits on anomalous WWγ and WWZ trilinear gauge boson couplings are presented. Prospects for further study of diboson production and anomalous couplings with the Upgraded Tevatron are also presented

  10. Combination of Tevatron searches for the standard model Higgs boson in the W+W- decay mode

    NARCIS (Netherlands)

    Aaltonen, T.; et al., [Unknown; Ancu, L.S.; de Jong, S.J.; Filthaut, F.; Galea, C.F.; Hegeman, J.G.; Houben, P.; Meijer, M.M.; Svoisky, P.; van den Berg, P.J.

    2010-01-01

    We combine searches by the CDF and D0 Collaborations for a Higgs boson decaying to W+W-. The data correspond to an integrated total luminosity of 4.8 (CDF) and 5.4 (D0) fb(-1) of p (p) over bar collisions at root s = 1.96 TeV at the Fermilab Tevatron collider. No excess is observed above background

  11. Study of the production of the Σ b with the CDF detector at the Tevatron

    Energy Technology Data Exchange (ETDEWEB)

    Calancha Paredes, Constantino [Complutense Univ. of Madrid (Spain)

    2011-02-01

    The composition of matter is a topic in which the man has been interested throughout History. Since the introduction of the atom by Democritus in the 5th century BC until the establishment of the Standard Model, our successful theory that contains our current knowledge on the matter and their interactions, it has come a long way trying to solve this fundamental question. The efforts of many of the greatest minds to perform crucial experiments and develop theoretical models have helped to get deeper insight into the origin of the matter. Today we know that indivisible atoms postulated by Democritus are no longer true, and they are actually composed of a nucleus made of protons and neutrons (nucleons) with orbiting electrons through electromagnetic interactions. Also the nucleons are not fundamental particles but are composed of more fundamental ones called quarks. According to the present state of our knowledge, matter is composed of two types of particles: quarks and leptons. Leptons are believed to be fundamental particles and can occur freely in nature. Quarks are also fundamental particles, and there are no free in nature, but are confined to form hadrons. The hadrons may consist of a quark and an antiquark (mesons) or three quarks or three antiquarks (baryons). These quarks and leptons interact through the exchange of particles called bosons. Figure 1.1 summary the elementary particles in the Standard Model. Despite its enormous success we know that the Standard Model is incomplete. Some of the issues left unresolved by the Standard Model are the mechanism for electroweak symmetry breaking, the mass spectrum of the Standard Model or that the Universe is much more matter than antimatter. That means that it should exist a more general theory which include the Standard Model as a valid approximation for low energy. This more general theory must give answers to the previous unresolved questions. Accumulate more experimental information is crucial to get a deeper

  12. Looking beyond the perfect lens

    International Nuclear Information System (INIS)

    Wee, W H; Pendry, J B

    2010-01-01

    The holy grail of imaging is the ability to see through anything. From the conservation of energy, we can easily see that to see through a lossy material would require lenses with gain. The aim of this paper therefore is to propose a simple scheme by which we can construct a general perfect lens, with gain-one that can restore both the phases and amplitudes of near and far fields.

  13. Measurement of the top quark mass using dilepton events and a neutrino weighting algorithm with the DOe experiment at the Tevatron (Run II)

    Energy Technology Data Exchange (ETDEWEB)

    Meyer, J.

    2007-07-01

    Several measurements of the top quark mass in the dilepton final states with the DOe experiment are presented. The theoretical and experimental properties of the top quark are described together with a brief introduction of the Standard Model of particle physics and the physics of hadron collisions. An overview over the experimental setup is given. The Tevatron at Fermilab is presently the highest-energy hadron collider in the world with a center-of-mass energy of 1.96 TeV. There are two main experiments called CDF and DOe, A description of the components of the multipurpose DOe detector is given. The reconstruction of simulated events and data events is explained and the criteria for the identification of electrons, muons, jets, and missing transverse energy is given. The kinematics in the dilepton final state is underconstraint. Therefore, the top quark mass is extracted by the so-called Neutrino Weighting method. This method is introduced and several different approaches are described, compared, and enhanced. Results for the international summer conferences 2006 and winter 2007 are presented. The top quark mass measurement for the combination of all three dilepton channels with a dataset of 1.05 1/fb yields: mtop=172.5{+-}5.5 (stat.) {+-} 5.8 (syst.) GeV. This result is presently the most precise top quark mass measurement of the DOe experiment in the dilepton chann el. It entered the top quark mass wold average from March 2007. (orig.)

  14. CONTACT LENS RELATED CORNEAL ULCER

    Directory of Open Access Journals (Sweden)

    AGARWAL P

    2010-01-01

    Full Text Available A corneal ulcer caused by infection is one of the major causes of blindness worldwide. One of the recent health concerns is the increasing incidence of corneal ulcers associated with contact lens user especially if the users fail to follow specific instruction in using their contact lenses. Risk factors associated with increased risk of contact lens related corneal ulcers are:overnight wear, long duration of continuous wear, lower socio-economic classes, smoking, dry eye and poor hygiene. The presenting symptoms of contact lens related corneal ulcers include eye discomfort, foreign body sensation and lacrimation. More serious symptoms are redness (especially circum-corneal injection, severe pain, photophobia, eye discharge and blurring of vision. The diagnosis is established by a thorough slit lamp microscopic examination with fluorescein staining and corneal scraping for Gram stain and culture of the infective organism. Delay in diagnosing and treatment can cause permanent blindness, therefore an early referral to ophthalmologist and commencing of antimicrobial therapy can prevent visual loss.

  15. SVX4: A New Deep-Submicron Readout IC for the Tevatron Collider at Fermilab

    Energy Technology Data Exchange (ETDEWEB)

    Krieger, B.; Alfonsi, S.; Bacchetta, N.; Centro, S.; Christofek, L.; Garcia-Sciveres, M.; Haber, C.; Hanagaki, K.; Hoff, J.; Johnson, M.; vonderLippe, H.; Lujan, P.; Mandelli, E.; Meng, G.; Nomerotski, A.; Pellet, D.; Rapidis, P.; Utes, M.; Walder, J.-P.; Weber, M.; Wester, W.; /LBL, Berkeley /Padua U. /INFN, Padua /Kansas U. /Fermilab /UC,

    2003-10-01

    SVX4 is the new silicon strip readout IC designed to meet the increased radiation tolerance requirements for Run IIb at the Tevatron collider. Devices have been fabricated, tested, and approved for production. The SVX4 design is a technology migration of the SVX3D design currently in use by CDF. Whereas SVX3D was fabricated in a 0.8 {micro}m radiation-hard process, SVX4 was fabricated in a standard 0.25 {micro}m mixed-signal CMOS technology using the ''radiation tolerant by design'' transistor topologies devised by the RD-49 collaboration. The specific cell layouts include digital cells developed by the ATLAS Pixel group, and full-custom analog blocks. Unlike its predecessors, the new design also includes the necessary features required for generic use by both the CDF and D0 experiments at Fermilab. Performance of the IC includes >20 MRad total dose tolerance, and {approx}2000 e-rms equivalent input noise charge with 40 pF input capacitance, when sampled at 132 ns period with an 80 ns preamp risetime. At the nominal digitize/readout rate of 106/53 MHz, the 9 mm x 6.3 mm die dissipates {approx}2 mW/channel average at 2.5 V. A review of typical operation, details of the design conversion process, and performance measurements are covered.

  16. Search for the Standard Model Higgs Boson in associated production with w boson at the Tevatron

    Energy Technology Data Exchange (ETDEWEB)

    Chun, Xu [Univ. of Michigan, Ann Arbor, MI (United States)

    2009-11-01

    A search for the Standard Model Higgs boson in proton-antiproton collisions with center-of-mass energy 1.96 TeV at the Tevatron is presented in this dissertation. The process of interest is the associated production of W boson and Higgs boson, with the W boson decaying leptonically and the Higgs boson decaying into a pair of bottom quarks. The dataset in the analysis is accumulated by the D0 detector from April 2002 to April 2008 and corresponding to an integrated luminosity of 2.7 fb-1. The events are reconstructed and selected following the criteria of an isolated lepton, missing transverse energy and two jets. The D0 Neural Network b-jet identification algorithm is further used to discriminate b jets from light jets. A multivariate analysis combining Matrix Element and Neural Network methods is explored to improve the Higgs boson signal significance. No evidence of the Higgs boson is observed in this analysis. In consequence, an observed (expected) limit on the ratio of σ (p$\\bar{p}$ → WH) x Br (H → b$\\bar{b}$) to the Standard Model prediction is set to be 6.7 (6.4) at 95% C.L. for the Higgs boson with a mass of 115 GeV.

  17. Search for super symmetry at the Tevatron using the trilepton signature

    Energy Technology Data Exchange (ETDEWEB)

    Dube, Sourabh Shishir [Rutgers Univ., New Brunswick, NJ (United States)

    2008-10-01

    This dissertation describes a search for the associated production of the supersymmetric particles, the chargino and the neutralino, through their R-parity conserving decays to three leptons and missing energy. This search is carried out using the data collected at the CDF experiment at the Tevatron √s = 1.96 TeV p$\\bar{p}$ collider at Fermilab. The results are obtained by combining five independent channels with varying signal to background ratio. Overall, a total of 6.4 ± 1.1 background events from standard model processes and 11.4 ± 1.1 signal events for a particular choice of mSUGRA model parameters are expected. The observation of 7 events in data is consistent with the standard model background expectation, and the mSUGRA model is constrained. Limits are set on the cross section of Chargino-Neutralino pair production, and a limit on the mass of the chargino is extracted. A method of obtaining model-independent results is also discussed.

  18. Impact of the A48 collimator on the Tevatron B0 dipoles

    CERN Document Server

    Nicolas, L Y

    2003-01-01

    To protect the CDF detector components in an event of an abort kicker prefire (AKP) in the Tevatron, a new collimator is to be installed at the A48 location during the summer 2003 shutdown. Detailed calculations have shown that this 0.5-m long ''single L-shape'' steel collimator will intercept a bunch of protons when such an incident occurs, providing reliable protection of the CDF main detector at an AKP. It will also mitigate the backgrounds induced by elastic beam-gas interactions upstream of B0. Although the Roman Pot detectors downstream of the A48 collimator will see an increased background, the amount of radiation they will receive either resulting from beam halo interactions in the collimator or during an AKP will not damage their sensitive parts. Secondaries resulting from beam halo interactions with the A48 collimator do not noticeably affect the downstream dipoles. The case of an AKP is quite different. As opposed to halo hits in the ''single-L shape'' unit (around 10 sup 5 p/s), a bunch lost on A4...

  19. Supersymmetry Reach of Tevatron Upgrades and LHC in Gauge-mediated Supersymmetry-breaking Models

    CERN Document Server

    Wang, Y

    2002-01-01

    We examine signals for sparticle production at the Fermilab Tevatron and the CERN Large Hadron Collider (LHC) within the framework of gauge mediated supersymmetry breaking models. We divide our analysis into four different model lines, each of which leads to qualitatively different signatures. We identify cuts to enhance the signal above Standard Model backgrounds, and use ISAJET to evaluate the SUSY reach of experiments at the Fermilab Main Injector and at its luminosity upgrades and also at the LHC. We examine the reach of the LHC via the canonical E/ and multilepton channels that have been advocated within the mSUGRA framework. For the model lines that we have examined, we find that the reach is at least as large, and frequently larger, than in the mSUGRA framework. For two of these model lines, we find that the ability to identify b-quarks and τ-leptons with high efficiency and purity is essential for the detection of the signal.

  20. SVX4 a new deep submicron readout IC for the Tevatron Collider at Fermilab

    CERN Document Server

    Krieger, B; Bacchetta, N; Centro, Sandro; Christofek, L; García-Sciveres, M; Haber, C; Hanagaki, K; Hoff, J; Johnson, M; Von der Lippe, H; Mandelli, E; Meng, G; Nomerotski, A; Pellet, D; Rapidis, P; Utes, M; Walder, J P; Weber, M; Wester, W; Wilkes, T; Yarema, R J; Yao, W; Zimmerman, T

    2004-01-01

    SVX4 is the new silicon strip readout IC designed to meet the increased radiation tolerance requirements for Run IIb at the Tevatron collider. Devices have been fabricated, tested, and approved for production. The SVX4 design is a technology migration of the SVX3D design currently in use by CDF. Whereas SVX3D was fabricated in a 0.8 mu m radiation-hard process, SVX4 was fabricated in a standard 0.25 mu m mixed-signal CMOS technology using the "radiation tolerant by design" transistor topologies devised by the RD-49 collaboration. The specific cell layouts include digital cells developed by the ATLAS Pixel group, and full-custom analog blocks. Unlike its predecessors, the new design also includes the necessary features required for generic use by both the CDF and DO experiments at Fermilab. Performance of the IC includes >20 Mrad total dose tolerance, and ~2000 e- rms equivalent input noise charge with 40 pF input capacitance, when sampled at 132 ns period with an 80 ns preamp risetime. At the nominal digitize...

  1. CP-violating supersymmetric Higgs boson at the Tevatron and LHC

    International Nuclear Information System (INIS)

    Das, Siba Prasad; Drees, Manuel

    2011-01-01

    We analyze the prospect for observing the intermediate neutral Higgs boson (h 2 ) in its decay to two lighter Higgs bosons (h 1 ) at the presently operating hadron colliders in the framework of the CP-violating minimal supersymmetric standard model using the PYTHIA event generator. We consider the lepton+4-jets+E T channel from associate Wh 2 production, with Wh 2 >Wh 1 h 1 >lvlbb*-bb*-. We require two, three or four tagged b jets. We explicitly consider all relevant standard model backgrounds, treating c jets separately from light flavor and gluon jets and allowing for mistagging. We find that it is very hard to observe this signature at the Tevatron, even with 20 fb*-*1 of data, in the LEP-allowed region of parameter space due to the small signal efficiency, even though the background is manageable. At the LHC, a priori huge standard model backgrounds can be suppressed by applying judiciously chosen kinematical selections. After all cuts, we are left with a signal cross section of around 0.5 fb, and a signal to background ratio between 1.2 and 2.9. According to our analysis this Higgs signal should be viable at the LHC in the vicinity of present LEP exclusion once 20 to 50fb*-*1 of data have been accumulated at √(s)=14 TeV.

  2. Top Quark Pair Production Cross Section and Forward-Backward Asymmetry at the Tevatron

    Energy Technology Data Exchange (ETDEWEB)

    Lister, Alison; /UC, Davis

    2008-10-01

    We present recent results on top quark pair production cross section and forward-backward asymmetry at the Tevatron. Three new cross section measurements from CDF and one new measurement from DO are presented that utilize the full dataset available. A new DO top cross section combination gives a ttbar production cross section of sigma ttbar = 7.83 + 0.46-0.45 (stat) + 0.64-0.53 (syst) +-0.48 (lumi). The new CDF cross section combination for ttbar production is found to be 7.0 +- 0.3 (stat) +- 0.4 (syst) +- 0.4 (lumi) pb giving a total uncertainty of 9%, very close to the that of the current best theoretical predictions. It is important to measure the top cross section in as many different channels as possible and investigate their compatibility. This is useful as new physics might show up differently in the different channels. Thus any significant discrepancy could be a sign of new physics. Three new measurements of the forward-backward asymmetry are also presented. The two CDF measurements unfold the observed asymmetry back to parton level in order to directly compare the values obtained with theoretical predictions. The DO measurement is not unfolded and therefore does not depend on the specific method used for unfolding.

  3. A Next-to-Leading Order QCD Analysis of Neutrino - Iron Structure Functions at the Tevatron

    Energy Technology Data Exchange (ETDEWEB)

    Seligman, William Glenn [Nevis Labs, Columbia U.

    1997-01-01

    Nucleon structure functions measured in neutrino-iron and antineutrinoiron charged-current interactions are presented. The data were taken in two high-energy high-statistics runs by the LAB-E detector at the Fermilab Tevatron. Structure functions are extracted from a sample of 950,000 neutrino and 170,000 antineutrino events with neutrino energies from 30 to 360 Ge V. The structure functions $F_2$ and $xF_3$ are compared with the the predictions of perturbative Quantum Chromodynamics (PQCD). The combined non-singlet and singlet evolution in the context of PQCD gives NL0(4) . 2 value of $\\Lambda^{NLO,(4)}_{\\overline MS}$ = 337 ± 28 (exp.) MeV, which corresponds to $\\alpha_s$ ($M^2_z$) = 0.119 ± 0.002 (exp.) ± 0.004 (theory), and with a gluon distribution given by $xG(x,Q^2_0 = 5 GeV^2$ ) = (2.22±0.34) x ($1-x)^{4.65 \\pm 0.68}$

  4. Primary intraocular lens implantation for penetrating lens trauma in Africa.

    Science.gov (United States)

    Bowman, R J; Yorston, D; Wood, M; Gilbert, C; Foster, A

    1998-09-01

    This study aimed to audit the surgical strategy of primary posterior chamber intraocular lens implantation for cases of recent penetrating trauma involving the lens in an African population. Retrospective, noncomparative case series. Seventy-two cases are reported, including all patients who underwent primary intraocular lens implantation for traumatic cataract extraction performed within 1 month of injury between 1988 and 1996. Demographic characteristics and follow-up attendance rates are analyzed. Surgical technique and the occurrence of intraoperative and postoperative complications are reported. Visual outcomes are reported with detailed analysis for cases of poor visual outcome. Mean age was 14.3 years (standard deviation = 11.1), 57 (79%) were male and 15 (21%) were female (chi-square = 23.66, P capsule had been breached by the trauma in 27 (38%) cases, and 15 of these required anterior vitrectomy. Capsular fixation of the implant was achieved in 49% of patients, the remainder having sulcus fixation. Intraoperative rupture of the posterior capsule occurred in four cases. The only common postoperative complication was acute fibrinous anterior uveitis, which occurred in 29 (40%) patients, and 32% of patients followed up for at least 6 months required secondary posterior capsulotomy. This was more common in younger patients (chi-square = 4.2, P < 0.05). Corrected postoperative visual acuities were available for 51 patients, of which 71% achieved 20/60 or better visual acuity. Patients 6 years of age or younger were less likely to achieve 20/60 (chi-square = 6.61, P = 0.01). This surgical strategy has proved successful, producing good visual results and causing no sight-threatening complications. Primary posterior capsulotomy may be appropriate for younger patients.

  5. The Higgs boson in the Standard Model theoretical constraints and a direct search in the wh channel at the Tevatron

    International Nuclear Information System (INIS)

    Huske, Nils Kristian

    2010-01-01

    We have presented results in two different yet strongly linked aspects of Higgs boson physics. We have learned about the importance of the Higgs boson for the fate of the Standard Model, being either only a theory limited to explaining phenomena at the electroweak scale or, if the Higgs boson lies within a mass range of 130 H Pl ). This could have direct implications on theories of cosmological inflation using the Higgs boson as the particle giving rise to inflation in the very early Universe, if it couples non-minimally to gravity, an effect that would only become significant at very high energies. After understanding the immense meaning of proving whether the Higgs boson exists and if so, at which mass, we have presented a direct search for a Higgs boson in associated production with a W boson in a mass range 100 H -1 of Tevatron data, we set limits on the production cross section times branching ratio. At the Tevatron, however, we are able to combine the sensitivity of our analyses not only across channels or analyses at a single experiment but also across both experiments, namely CDF and D0. This yields to the so-called Tevatron Higgs combination which, in total, combines 129 analyses from both experiments with luminosities of up to 6.7 fb -1 . The results of a previous Tevatron combination led to the first exclusion of possible Higgs boson masses since the LEP exclusion in 2001. The latest Tevatron combination from July 2010 can be seen in Fig. 111 and limits compared to the Standard Model expectation are listed in Table 23. It excludes a SM Higgs boson in the regions of 100 H H -1 projection is a rather conservative outlook for the coming year of data taking as the Tevatron runs smoothly and the run till the end of 2011 is assured. By now, already 9 fb -1 have been recorded by the two experiments. As the extrapolation plot shows, this amount of luminosity will allow to exclude the Higgs boson over a wide mass range at a 95% C.L. With the LHC at CERN now

  6. Finding the Higgs boson of the standard model in the channel ZH → e+e-b$\\bar{b}$ with the D0 detector at the Tevatron; Recherche du boson de Higgs du nideke standard dans le canal ZH → e+e-b$\\bar{b}$ avec le detecteur DØ aupres du Tevatron

    Energy Technology Data Exchange (ETDEWEB)

    Calpas, Betty Constante [Univ. of the Mediterranean, Marseille (France)

    2010-06-11

    The organization of this thesis consists of three main ideas: the first presents the theoretical framework and experimental, as well as objects used in the analysis and the second relates to the various work tasks of service that I performed on the calorimeter, and the third is the search for the Higgs boson in the channel ZH → e+e-b$\\bar{b}$. Thus, this thesis has the following structure: Chapter 1 is an introduction to the standard model of particle physics and the Higgs mechanism; Chapter 2 is an overview of the complex and the acceleration of the Tevatron at Fermilab DØ detector; Chapter 3 is an introduction to physical objects used in this thesis; Chapter 4 presents the study made on correcting the energy measured in the calorimeter; Chapter 5 describes the study of certification of electrons in the calorimeter; Chapter 6 describes the study of certification of electrons in the intercryostat region of calorimeter; Chapter 7 Detailed analysis on the search for Higgs production in the channel ZH → e+e-b$\\bar{b}$; and Chapter 8 presents the final results of the calculations of upper limits to the production cross section of the Higgs boson on a range of low masses.

  7. Hard contact lens-induced metabolic changes in rabbit corneas.

    Science.gov (United States)

    Tsubota, K; Kenyon, K R; Cheng, H M

    1989-11-01

    The biochemistry of contact lens-cornea interaction is not well understood, although previous studies have suggested that corneal metabolic changes may be the underlying factor in morphological alterations. Using a rabbit model, this interaction has been examined with 31P nuclear magnetic resonance (NMR) spectroscopy, which detects signals principally from the epithelium. The examination was supplemented with electron microscopy and histochemistry. Polymethylmethacrylate lenses caused reversible changes, including activation of anaerobic glycolysis and disturbance of membrane metabolite levels. These changes were far more severe than those occurring during prolonged eye closure. There appears to be an association between cellular deterioration and loss of membrane metabolites. On the other hand, oxygen-permeable silicone lenses allowed maintenance of nearly normal metabolic patterns. These results show multifaceted corneal response to hard contact lens wear.

  8. A tunable microplasma gradient-index lens for millimeter waves

    Energy Technology Data Exchange (ETDEWEB)

    Venkattraman, Ayyaswamy [School of Engineering, University of California Merced, Merced, California 95343 (United States)

    2015-10-15

    This work presents proof of concept of a novel application of field emission assisted (FEA) microplasmas that exploits the relatively high plasma number densities encountered in these devices. We hypothesize that the number density gradients and the resulting gradient in the microplasma relative permittivity/refractive index can be utilized as a tunable diverging lens with on/off ability to defocus waves in the Terahertz regime. Electron number density profiles obtained from one-dimensional particle-in-cell with Monte Carlo collisions simulations for a typical FEA microplasma are used to determine the relative permittivity and conductivity profiles. Frequency domain wave propagation simulations using these profiles show that sub-mm waves can be controlled using the microplasma lens with the degree of defocusing depending on the wavelength. In spite of the non-zero conductivity, the medium is not significantly lossy at the frequencies considered.

  9. HiggsBounds 2.0.0. Confronting neutral and charged Higgs sector predictions with exclusion bounds from LEP and the Tevatron

    Energy Technology Data Exchange (ETDEWEB)

    Bechtle, P.; Weiglein, G. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Brein, O. [Freiburg Univ. (Germany). Physikalisches Inst.; Heinemeyer, S. [Instituto de Fisica de Cantabria (CSIC-UC), Santander (Spain); Williams, K.E. [Bonn Univ. (Germany). Bethe Center for Theoretical Physics

    2011-03-15

    HiggsBounds 2.0.0 is a computer code which tests both neutral and charged Higgs sectors of arbitrary models against the current exclusion bounds from the Higgs searches at LEP and the Tevatron. As input, it requires a selection of model predictions, such as Higgs masses, branching ratios, effective couplings and total decay widths. HiggsBounds 2.0.0 then uses the expected and observed topological cross section limits from the Higgs searches to determine whether a given parameter scenario of a model is excluded at the 95% C.L. by those searches. Version 2.0.0 represents a significant extension of the code since its first release (1.0.0). It includes now 28/53 LEP/Tevatron Higgs search analyses, compared to the 11/22 in the first release, of which many of the ones from the Tevatron are replaced by updates. As a major extension, the code allows now the predictions for (singly) charged Higgs bosons to be confronted with LEP and Tevatron searches. Furthermore, the newly included analyses contain LEP searches for neutral Higgs bosons (H) decaying invisibly or into (non flavour tagged) hadrons as well as decay-mode independent searches for neutral Higgs bosons, LEP searches via the production modes {tau}{sup +}{tau}{sup -}H and b anti bH, and Tevatron searches via t anti tH. Also, all Tevatron results presented at the ICHEP'10 are included in version 2.0.0. As physics applications of HiggsBounds 2.0.0 we study the allowed Higgs mass range for model scenarios with invisible Higgs decays and we obtain exclusion results for the scalar sector of the Randall-Sundrum model using up-to-date LEP and Tevatron direct search results. (orig.)

  10. Research on one manual zoom liquid lens

    Science.gov (United States)

    Zhao, Cunhua; Shi, Yongpeng; Li, Wenjiao; Li, Congcong

    2011-11-01

    In liquid zoom lens, the accurate fixed-focus location needs the accurate calculation of focal length. That is to say, the accurate calculation of surface curvature must be obtained. Therefore, the research of their relation in liquid zoom lens becomes extremely important which has a directly theoretical instruction for the design of liquid zoom lenses. In our paper, the relation is studied. A manual liquid lens is reported which has upper and nether components with specificaton Φ12×5mm. The zoom lens is obtained by the upper component circumvolving down into the nether components.

  11. Numerical analyses of planer plasmonic focusing lens

    Science.gov (United States)

    Chou, Yen-Yu; Lee, Yeeu-Chang

    2018-03-01

    The use of polystyrene (PS) sphere lithography has been widely applied in the fabrication of micron and nano structures, due to their low cost and ease of fabrication in large scale applications. This study evaluated the feasibility of plasmonic lens base on metal thin films with nanohole structures fabricated by using PS sphere lithography through three-dimensional (3D) finite difference time domain (FDTD) method. We calculated the intensity profile of lens with various wavelength of incident light, lens size, cutting positions, diameters of nanohole, and periods of nanohole to investigate the geometric parameters influence on the focusing properties of the plasmonic lens.

  12. Exchange of tears under a contact lens is driven by distortions of the contact lens.

    Science.gov (United States)

    Maki, Kara L; Ross, David S

    2014-12-01

    We studied the flow of the post-lens tear film under a soft contact lens to understand how the design parameters of contact lenses can affect ocular health. When a soft contact lens is inserted, the blinking eyelid causes the lens to stretch in order to conform to the shape of the eye. The deformed contact lens acts to assume its un-deformed shape and thus generates a suction pressure in the post-lens tear film. In consequence, the post-lens tear fluid moves; it responds to the suction pressure. The suction pressure may draw in fresh fluid from the edge of the lens, or it may eject fluid there, as the lens reassumes its un-deformed shape. In this article, we develop a mathematical model of the flow of the post-lens tear fluid in response to the mechanical suction pressure of a deformed contact lens. We predict the amount of exchange of fluid exchange under a contact lens and we explore the influence of the eye's shape on the rate of exchange of fluid. © The Author 2014. Published by Oxford University Press on behalf of the Society for Integrative and Comparative Biology. All rights reserved. For permissions please email: journals.permissions@oup.com.

  13. Aquaporin 0 plays a pivotal role in refractive index gradient development in mammalian eye lens to prevent spherical aberration

    Energy Technology Data Exchange (ETDEWEB)

    Kumari, S. Sindhu [Physiology and Biophysics, Stony Brook University, Stony Brook, NY (United States); Varadaraj, Kulandaiappan, E-mail: kulandaiappan.varadaraj@stonybrook.edu [Physiology and Biophysics, Stony Brook University, Stony Brook, NY (United States); SUNY Eye Institute, New York, NY (United States)

    2014-10-03

    . Transmission and scanning electron micrographs of lenses of both mouse models showed increased extracellular space between fiber cells. Water content determination study showed increase in water in the lenses of these mouse models. In summary, lens transparency, CTCA and compact packing of fiber cells were affected due to the loss of 50% AQP0 leading to larger extracellular space, more water content and SA, possibly due to alteration in RING. To our knowledge, this is the first report identifying the role of AQP0 in RING development to ward off lens SA during focusing.

  14. RHIC electron lenses upgrades

    Energy Technology Data Exchange (ETDEWEB)

    Gu, X. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Altinbas, Z. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Bruno, D. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Binello, S. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Costanzo, M. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Drees, A. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Fischer, W. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Gassner, D. M. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Hock, J. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Hock, K. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Harvey, M. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Luo, Y. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Marusic, A. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Mi, C. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Mernick, K. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Minty, M. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Michnoff, R. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Miller, T. A. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Pikin, A. I. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Robert-Demolaize, G. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Samms, T. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Shrey, T. C. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Schoefer, V. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Tan, Y. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Than, R. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Thieberger, P. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; White, S. M. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.

    2015-05-03

    In the Relativistic Heavy Ion Collider (RHIC) 100 GeV polarized proton run in 2015, two electron lenses were used to partially compensate for the head-on beam-beam effect for the first time. Here, we describe the design of the current electron lens, detailing the hardware modifications made after the 2014 commissioning run with heavy ions. A new electron gun with 15-mm diameter cathode is characterized. The electron beam transverse profile was measured using a YAG screen and fitted with a Gaussian distribution. During operation, the overlap of the electron and proton beams was achieved using the electron backscattering detector in conjunction with an automated orbit control program.

  15. HiggsSignals. Confronting arbitrary Higgs sectors with measurements at the Tevatron and the LHC

    Energy Technology Data Exchange (ETDEWEB)

    Bechtle, Philip [Bonn Univ. (Germany). Physikalisches Inst.; Heinemeyer, Sven [Instituto de Fisica de Cantabria (CSIC-UC), Santander (Spain); Staal, Oscar [Stockholm Univ. (Sweden). The Oskar Klein Centre; Stefaniak, Tim [Bonn Univ. (Germany). Physikalisches Inst.; Bonn Univ. (Germany). Bethe Center for Theoretical Physics; Weiglein, Georg [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)

    2013-05-15

    HiggsSignals is a Fortran90 computer code that allows to test the compatibility of Higgs sector predictions against Higgs rates and masses measured at the LHC or the Tevatron. Arbitrary models with any number of Higgs bosons can be investigated using a model-independent input scheme based on HiggsBounds. The test is based on the calculation of a {chi}{sup 2} measure from the predictions and the measured Higgs rates and masses, with the ability of fully taking into account systematics and correlations for the signal rate predictions, luminosity and Higgs mass predictions. It features two complementary methods for the test. First, the peak-centered method, in which each observable is defined by a Higgs signal rate measured at a specific hypothetical Higgs mass, corresponding to a tentative Higgs signal. Second, the mass-centered method, where the test is evaluated by comparing the signal rate measurement to the theory prediction at the Higgs mass predicted by the model. The program allows for the simultaneous use of both methods, which is useful in testing models with multiple Higgs bosons. The code automatically combines the signal rates of multiple Higgs bosons if their signals cannot be resolved by the experimental analysis. We compare results obtained with HiggsSignals to official ATLAS and CMS results for various examples of Higgs property determinations and find very good agreement. A few examples of HiggsSignals applications are provided, going beyond the scenarios investigated by the LHC collaborations. For models with more than one Higgs boson we recommend to use HiggsSignals and HiggsBounds in parallel to exploit the full constraining power of Higgs search exclusion limits and the measurements of the signal seen at m{sub H} {approx} 125.5 GeV.

  16. [Acanthamoeba isolation from contact lens solution of contact lens wearers without keratitis].

    Science.gov (United States)

    Watanabe, R; Ishibashi, Y; Hommura, S; Ishii, K

    1994-05-01

    Acanthamoeba keratitis seems to be associated with wearing contact lenses. As controls, we surveyed contact lens wearers without keratitis. Contact lens solutions of 93 persons were examined in order to identify risk factors for contamination by Acanthamoeba. Therefore, the contact lens disinfection system and storage schedules were studied in each case. Acanthamoeba organisms were isolated from 4 specimens (4.3%). The incidence of Acanthamoeba was higher in specimens of soft contact lens solution than in those of hard contact lens solution, and all the Acanthamoeba positive cases had been using tap water.

  17. Primary anterior chamber intraocular lens for the treatment of severe crystalline lens subluxation.

    Science.gov (United States)

    Hoffman, Richard S; Fine, I Howard; Packer, Mark

    2009-10-01

    Subluxated cataractous and clear lenses are commonly treated by limbal or pars plana lensectomy followed by primary or secondary intraocular lens (IOL) implantation. Adjunctive capsular prosthetic devices have facilitated lens removal and IOL centration in these challenging cases but have also added complexity and potential complications to the procedure. Although crystalline lens extraction may be required to clear the visual axis in mild to moderate lens subluxations, we propose insertion of a primary anterior chamber IOL without lens extraction in severe subluxations when the eye is optically aphakic or can be made functionally aphakic following neodymium:YAG laser zonulysis. Two cases demonstrating this approach are presented.

  18. Plasma lenses for focusing relativistic electron beams

    International Nuclear Information System (INIS)

    Govil, R.; Wheeler, S.; Leemans, W.

    1997-01-01

    The next generation of colliders require tightly focused beams with high luminosity. To focus charged particle beams for such applications, a plasma focusing scheme has been proposed. Plasma lenses can be overdense (plasma density, n p much greater than electron beam density, n b ) or underdense (n p less than 2 n b ). In overdense lenses the space-charge force of the electron beam is canceled by the plasma and the remaining magnetic force causes the electron beam to self-pinch. The focusing gradient is nonlinear, resulting in spherical aberrations. In underdense lenses, the self-forces of the electron beam cancel, allowing the plasma ions to focus the beam. Although for a given beam density, a uniform underdense lens produces smaller focusing gradients than an overdense lens, it produces better beam quality since the focusing is done by plasma ions. The underdense lens can be improved by tapering the density of the plasma for optimal focusing. The underdense lens performance can be enhanced further by producing adiabatic plasma lenses to avoid the Oide limit on spot size due to synchrotron radiation by the electron beam. The plasma lens experiment at the Beam Test Facility (BTF) is designed to study the properties of plasma lenses in both overdense and underdense regimes. In particular, important issues such as electron beam matching, time response of the lens, lens aberrations and shot-to-shot reproducibility are being investigated

  19. Protection of the eye lens

    International Nuclear Information System (INIS)

    2015-01-01

    The limit of radiation exposure for eye lens is going to decrease dramatically from 150 to 20 mSv as a transposition into the French law of a CIPR (International Commission for Radiation Protection) directive. Sanitary studies have shown that radiologists are more likely by a factor of 3.8 to get eye lens opacities than the rest of the population. The wearing of protective glasses is recommended and in order to get a better monitoring of the radiation dose new dosimeters have been designed, they can be worn on the glass frame of directly stuck on the skin near the eyes. A study has shown that veterinary surgeons that are accustomed to stay near animals to keep them quiet during radiological exams are prone to receive high doses as well as physicians that use hypnosis to decrease the level of anxiety of their patients during radiological exams. Radiation exposure of radiologists can be mitigated through: the use of protective shields and equipment and the optimization of the dose delivered to the patient. (A.C.)

  20. Color corrected Fresnel lens for solar concentration

    International Nuclear Information System (INIS)

    Kritchman, E.M.

    1979-01-01

    A new linear convex Fresnel lens with its groove side down is described. The design philosophy is similar to the highly concentrating two focal Fresnel lens but including a correction for chromatic aberration. A solar concentration ratio as high as 80 is achieved. For wide acceptance angles the concentration nears the theoretical maximum. (author)

  1. Modified suturing contact lens for penetrating keratoplasty.

    Science.gov (United States)

    Kramer, S G; Stewart, H L

    1978-11-01

    The authors have previously described a suturing contact lens that protects the corneal endothelium by aiding in the maintenance of the anterior chamber during penetrating keratoplasty. This report describes structural modifications of the suturing contact lens, which improve its stability and effectiveness. An additional configuration for use in corneal lacerations is presented.

  2. Charged black lens in de Sitter space

    Science.gov (United States)

    Tomizawa, Shinya

    2018-02-01

    We obtain a charged black lens solution in the five-dimensional Einstein-Maxwell-Chern-Simons theory with a positive cosmological constant. It is shown that the solution obtained here describes the formation of a black hole with the spatial cross section of a sphere from that of the lens space of L (n ,1 ) in five-dimensional de Sitter space.

  3. Contact Lens Use in the Civil Airman Population

    National Research Council Canada - National Science Library

    Nakagawara, Van

    2002-01-01

    ...) aeromedical certificate. Although contact lens technology has advanced dramatically in recent years, the aviation environment may still have adverse effects on contact lens performance in some flight situations...

  4. Corrected electrostatic lens systems for ion beams

    International Nuclear Information System (INIS)

    Dalgish, R.L.

    1981-01-01

    Recent work in our laboratory has introduced a new class of electrostatic focus forming element for beams, the ELCO lens. It compares favourably with the electrostatic and magnetic quadrupole elements conventionally used for microbeam formation. The ELCO lens does however have disadvantages associated with apertures and alignment. We have continued with the development of ion beam lenses and have evolved a further class of lens element which eliminates aperture and alignment problems. This new element can be combined like optical lenses into an aberration corrected system. Experimental measurement on the basic lens element has confirmed mathematical analysis of ion trajectories through the element. This mathematical analysis predicts that the basic element can be combined into a corrected lens system for, either: (1) high resolution microprobe formation with intrinsic rastering ability, the spot size limited only by the beam properties; or (2) high quality image formation with large magnification/demagnification ratio and wide angular aperture. (orig.)

  5. Search for the scalar partner of the top quark and contribution to the improvement of the calorimetry of the experiment D zero for the phase 2 of Tevatron; Recherche du partenaire supersymetrique du quark top et contribution a l'amelioration de la calorimetrie de l'experience D zero pour la phase 2 du tevatron

    Energy Technology Data Exchange (ETDEWEB)

    Olivier, B

    2001-04-01

    Supersymmetry could be the most natural extension of the Standard Model. In this thesis we present a new search for the sTop, the hypothetical scalar partner of the Top quark, that we performed in the framework of the Minimal Supersymmetric Standard Model (MSSM), using the Run I data of the DO experiment, which corresponds to an integrated luminosity of 108 pb{sup -1}. We selected events with one electron, one muon and missing transverse energy in the final state, which can be the decay product of pair of sTop quarks in 3 (t-tilde {yields} bl{nu}-tilde), or 4-body (t-tilde {yields} b{chi}-tilde{sub 1}{sup 0}l{nu}{sub l}). No signal is seen and the results are interpreted in terms of limits on the sTop production cross-section and exclusion regions in the parameter space (m{sub t}-tilde,m{sub {chi}}-tilde{sub 1{sup 0}}) or (m{sub t}-tilde,m{sub {nu}}-tilde). This new type of selection at the Tevatron for the search of the sTop allowed us to put stronger constraints than those previously published at LEP or at the Tevatron in the t-tilde {yields} bl{nu}-tilde channel, and the first limits ever set in the 4-body decay channel. For the 3-body channel, assuming that the sneutrino is the lightest supersymmetric particle (LSP), the excluded region at 95% confidence level extends up to a sTop mass of 142 (130) GeV if the sneutrino mass (m{sub {nu}}-tilde) is 43 (86) GeV. If the 4-body decay channel dominates, assuming that the neutralino is the LSP, the limit depends on the sneutrino mass. If it is light enough (m{sub {nu}}-tilde {approx}< 100 GeV) this limit reaches a sTop mass of 132 GeV for a neutralino mass of 60 GeV. In all searches for new particles, the calorimetry plays a crucial role from the experimental point of view. The expected increase in integrated luminosity in the Run II which started on the 1. of March 2001, and the detector upgrade which has been achieved over the last three years will allow to extend these exclusion domains or to discover the sTop. We

  6. Top quarks at the Tevatron: Measurements of the top quark production and decay with the D0 experiment

    Energy Technology Data Exchange (ETDEWEB)

    Strandberg, Jonas [Stockholm Univ. (Sweden)

    2006-01-01

    This thesis presents two measurements of the to pquark using 230 pb-1 of data recorded with the D0 detector at the Tevatron accelerator. The first measurement determines the top pair production cross section at √s = 1.96 TeV in proton-antiproton collisions. In the standard model of particle physics the top quark decays almost exclusively into a W boson and a b quark. Candidate events are selected by requiring that at least one jet in the event is tagged with the secondary vertex algorithm.

  7. Measurement of the Top Mass in the All - Jets Channel with the D0 Detector at the Fermilab Tevatron Collider

    Energy Technology Data Exchange (ETDEWEB)

    Connolly, Brian M. [Florida State U.

    2002-01-01

    We describe a measurement of the top quark mass in $t\\overline{t}$ production where the final state is 6 or more jets, which is otherwise known as the all-jets channel. The mass is extracted from 110.2 $pb^{-1}$ of data taken with the D0 detector at the Fermilab Tevatron (center-of-mass energy ps = 1.8 TeV) from 1993-96. The top quark mass is measured to be $176.6^{+17.1}_{-13.4}$ $GeV/c^2$. The corresponding cross section is estimated to be $11.5^{+4.9}_{-4.7}$ pb.

  8. The Higgs boson in the Standard Model theoretical constraints and a direct search in the wh channel at the Tevatron

    Energy Technology Data Exchange (ETDEWEB)

    Huske, Nils Kristian [Pierre and Marie Curie Univ., Paris (France); Bielefeld Univ. (Germany)

    2010-09-10

    We have presented results in two different yet strongly linked aspects of Higgs boson physics. We have learned about the importance of the Higgs boson for the fate of the Standard Model, being either only a theory limited to explaining phenomena at the electroweak scale or, if the Higgs boson lies within a mass range of 130 < mH < 160 GeV the SM would remain a self consistent theory up to highest energy scales O(mPl). This could have direct implications on theories of cosmological inflation using the Higgs boson as the particle giving rise to inflation in the very early Universe, if it couples non-minimally to gravity, an effect that would only become significant at very high energies. After understanding the immense meaning of proving whether the Higgs boson exists and if so, at which mass, we have presented a direct search for a Higgs boson in associated production with a W boson in a mass range 100 < mH < 150 GeV. A light Higgs boson is favored regarding constraints from electroweak precision measurements. As a single analysis is not yet sensitive for an observation of the Higgs boson using 5.3 fb-1 of Tevatron data, we set limits on the production cross section times branching ratio. At the Tevatron, however, we are able to combine the sensitivity of our analyses not only across channels or analyses at a single experiment but also across both experiments, namely CDF and D0. This yields to the so-called Tevatron Higgs combination which, in total, combines 129 analyses from both experiments with luminosities of up to 6.7 fb-1. The results of a previous Tevatron combination led to the first exclusion of possible Higgs boson masses since the LEP exclusion in 2001. The latest Tevatron combination from July 2010 can be seen in Fig. 111 and limits compared to the Standard Model expectation are listed in Table 23. It excludes a SM Higgs boson in the regions of 100 < mH < 109 GeV as well as 158 < m

  9. Experimental systematic uncertainties (and object reconstruction) on top physics, their correlations, comparison ATLAS vs CMS (vs Tevatron) and common agreements

    CERN Document Server

    Costa, M J

    2014-01-01

    The experimental systematic uncertainties associated to the reconstruction and calibration of the objects appearing in top quark final states at the LHC and Tevatron are discussed. The strategies followed in the ATLAS and CMS experiments are compared in detail for the cases of the jet energy scale and $b$-tagging calibrations, where a categorisation of the associated uncertainty sources as well as the corresponding correlations across experiments has been proposed. The estimate of the non-prompt and fake lepton background to the top quark leptonic channels is also discussed.

  10. Search for beyond standard model physics (non-SUSY) in final states with photons at the Tevatron

    Energy Technology Data Exchange (ETDEWEB)

    Palencia, Jose Enrique; /Fermilab

    2009-01-01

    We present the results of searches for non-standard model phenomena in photon final states. These searches use data from integrated luminosities of {approx} 1-4 fb{sup -1} of p{bar p} collisions at {radical}s = 1.96 TeV, collected with the CDF and D0 detectors at the Fermilab Tevatron. No significant excess in data has been observed. We report limits on the parameters of several BSM models (excluding SUSY) for events containing photons.

  11. Combination of Tevatron searches for the standard model Higgs boson in the W+W- decay mode

    Energy Technology Data Exchange (ETDEWEB)

    Aaltonen, T.; Abazov, V.M.; Gregores, E.M.; Mercadante, P.G.; /ABC Federal U.; Hebbeker, T.; Kirsch, M.; Meyer, A.; Sonnenschein, L.; /Aachen, Tech. Hochsch.; Avila, C.; Gomez, B.; Mendoza, L.; /Andes U., Bogota /Argonne /Arizona U. /Athens U. /Barcelona, IFAE /Baylor U. /Bonn U. /Boston U. /Brandeis U.

    2010-01-01

    We combine searches by the CDF and D0 collaborations for a Higgs boson decaying to W{sup +}W{sup -}. The data correspond to an integrated total luminosity of 4.8 (CDF) and 5.4 (D0) fb{sup -1} of p{bar p} collisions at {radical}s = 1.96 TeV at the Fermilab Tevatron collider. No excess is observed above background expectation, and resulting limits on Higgs boson production exclude a standard-model Higgs boson in the mass range 162-166 GeV at the 95% C.L.

  12. Cholesterol Bilayer Domains in the Eye Lens Health: A Review.

    Science.gov (United States)

    Widomska, Justyna; Subczynski, Witold K; Mainali, Laxman; Raguz, Marija

    2017-12-01

    The most unique biochemical characteristic of the eye lens fiber cell plasma membrane is its extremely high cholesterol content, the need for which is still unclear. It is evident, however, that the disturbance of Chol homeostasis may result in damages associated with cataracts. Electron paramagnetic resonance methods allow discrimination of two types of lipid domains in model membranes overloaded with Chol, namely, phospholipid-cholesterol domains and pure Chol bilayer domains. These domains are also detected in human lens lipid membranes prepared from the total lipids extracted from lens cortices and nuclei of donors from different age groups. Independent of the age-related changes in phospholipid composition, the physical properties of phospholipid-Chol domains remain the same for all age groups and are practically identical for cortical and nuclear membranes. The presence of Chol bilayer domains in these membranes provides a buffering capacity for cholesterol concentration in the surrounding phospholipid-Chol domains, keeping it at a constant saturating level and thus keeping the physical properties of the membrane consistent with and independent of changes in phospholipid composition. It seems that the presence of Chol bilayer domains plays an integral role in the regulation of cholesterol-dependent processes in fiber cell plasm membranes and in the maintenance of fiber cell membrane homeostasis.

  13. Top quark mass measurement in the dilepton channel during the D0 experiment at the Tevatron. Mesure de la masse du quark top dans les canaux di-leptoniques auprès de l’expérience D0 au Tevatron

    Energy Technology Data Exchange (ETDEWEB)

    Croc, Aurelien [Commissariat a l' Energie Atomique et aux Energies Alternatives (CEA) Saclay, Gif-sur-Yvette (France). IRFU

    2011-01-01

    The top quark is the heaviest standard model quark. Discovered in 1995 by the two Tevatron experiments it has atypical properties. In particular its time life is so short that it decays before hadronizing, so the top quark mass could be measured with a high precision. Data collected by the DØ experiment between 2002 and 2009, which represent an integrated luminosity of 5.4 fb⁻¹, are used to measure the top quark mass by using the matrix element method in the three dilepton channels: dielectron, electron--muon and dimuon. The measured mass, 174.0 ± 1.8 (stat.) ± 2.4 (syst.) GeV, is in a good agreement with other measurements and limited by the systematic uncertainties for the first time in these channels. In this thesis different approaches have been studied to improve the accuracy of this measurement: the use of b-quark jet identification in order to optimize the selection of top--anti-top events and a better determination of the main systematic uncertainties. A special attention has been paid to the Monte-Carlo simulation of muons in D0: the improved smearing procedure for the simulated muons, discussed in this thesis, will be used to increase the accuracy of the top properties measurements as well as the precision of many other D0 measurements.

  14. Effects of gamma radiation on rabbit lens

    International Nuclear Information System (INIS)

    Ordahl, J.N.; Gorthy, W.C.

    1982-01-01

    Eyes of young New Zealand white rabbits were irradiated with 2000 rads of gamma radiation ( 60 Co) and the eyes removed at 2, 8, 16, and 30 days post-irradiation for electron microscopic analysis. Lenses were treated histochemically for acid phosphatase localization to examine the role of lysosomal enzymes in the early development of radiation cataracts. Intercellularly located acid phosphatase reaction product, noted in the epithelium and subjacent cortex, was more prevalent after irradiation, especially in central and transitional epithelial zones. In the central zone small vesicles typically were most numerous in areas of extensive intercellular reaction product. The occurrence of discrete packets of reaction product within the vesicles and the adjoining intercellular space, plus the resemblance of the peripheral vesicles to small Golgi vesicles also containing reaction product, suggested an exocytotic release of the enzyme. These appearances suggest that lysosomal hydrolases are released extracellularly by a secretory mechanism accelerated by radiation and that these hydrolases may play a role in both physiological and pathological functions of the lens. (author)

  15. Investigation of lens morphology and mechanical characteristics of lens capsule and lens nucleus in patients with agerelated and diabetic cataract

    Directory of Open Access Journals (Sweden)

    A. S. Tishkova

    2014-07-01

    Full Text Available Purpose: To investigate the influence of carbohydrate metabolism on the structure and mechanical properties of the lens capsule and nucleus.Methods: Human lens pathology was studied in different forms of cataract. 220 patients with a cataract (220 eyes were included in this study. Morphological, immunohystological and immunocytochemical investigations of lens substance (antibodies to a- (a-А and a-В, b-, g- crystallines, spectroscopic analyses of smears and morphometric analyses of slices, investigation of lens morphology and mechanical caracteristics of lens capsule and lens nucleus were performed.Results: The capsule of the lens in patients with senile cataract contains more Na+, Cl-. The capsule of the lens in patients with senile cataract contains more Ca2+, O. Mechanical strength of the capsule in the case of diabetes mellitus was lower comparatively with senile cataract in the same age groups. More significant expression of a-В and b-crystallines was found in patients with diabetes mellitus comparatively with patients with age-related cataract. Morphological features were founded in patients with cortical and nuclear forms of senile cataract and the diabetic cataract.Conclusion: During surgery (ultrasonic microcoaxial phacoemulsification the equivalent of ultrasound was recorded. Lower density of the lens nucleus of patients with diabetes mellitus made it possible to use lower energy parameters. Using the torsion ultrasound in those cases allowed us to decrease the influence of ultrasound on eye tissues and reduce the time of achieving the maximum BCVA in the postsurgical period.

  16. Investigation of lens morphology and mechanical characteristics of lens capsule and lens nucleus in patients with agerelated and diabetic cataract

    Directory of Open Access Journals (Sweden)

    A. S. Tishkova

    2013-01-01

    Full Text Available Purpose: To investigate the influence of carbohydrate metabolism on the structure and mechanical properties of the lens capsule and nucleus.Methods: Human lens pathology was studied in different forms of cataract. 220 patients with a cataract (220 eyes were included in this study. Morphological, immunohystological and immunocytochemical investigations of lens substance (antibodies to a- (a-А and a-В, b-, g- crystallines, spectroscopic analyses of smears and morphometric analyses of slices, investigation of lens morphology and mechanical caracteristics of lens capsule and lens nucleus were performed.Results: The capsule of the lens in patients with senile cataract contains more Na+, Cl-. The capsule of the lens in patients with senile cataract contains more Ca2+, O. Mechanical strength of the capsule in the case of diabetes mellitus was lower comparatively with senile cataract in the same age groups. More significant expression of a-В and b-crystallines was found in patients with diabetes mellitus comparatively with patients with age-related cataract. Morphological features were founded in patients with cortical and nuclear forms of senile cataract and the diabetic cataract.Conclusion: During surgery (ultrasonic microcoaxial phacoemulsification the equivalent of ultrasound was recorded. Lower density of the lens nucleus of patients with diabetes mellitus made it possible to use lower energy parameters. Using the torsion ultrasound in those cases allowed us to decrease the influence of ultrasound on eye tissues and reduce the time of achieving the maximum BCVA in the postsurgical period.

  17. Cuba Through A New Lens

    Directory of Open Access Journals (Sweden)

    Jean Stubbs

    2008-12-01

    Full Text Available [First paragraph] The Origins of the Cuban Revolution Reconsidered. Samuel Farber. Chapel Hill: University of North Carolina Press, 2006. x + 212 pp. (Paper US$ 19.95 Cuba: A New History. Ric hard Gott . New Haven: Yale University Press, 2005. xii + 384 pp. (Paper US$ 17.00 Havana: The Making of Cuban Culture. Antoni Kapcia. Oxford: Berg Publishers, 2005. xx + 236 pp. (Paper US$ 24.95 Richard Gott, Antoni Kapcia, and Samuel Farber each approach Cuba through a new lens. Gott does so by providing a broad-sweep history of Cuba, which is epic in scope, attaches importance to social as much as political and economic history, and blends scholarship with flair. Kapcia homes in on Havana as the locus for Cuban culture, whereby cultural history becomes the trope for exploring not only the city but also Cuban national identity. Farber revisits his own and others’ interpretations of the origins of the Cuban Revolution.

  18. Radiation studies in Lens culinaris

    International Nuclear Information System (INIS)

    Sinha, S.S.N.

    1977-01-01

    Estimation of chromosomal aberrations in flowers of Lens culinaris according to their sequence of development in the plants at 4, 8 and 12 Kr in the M 1 generation, showed that the later formed flowers had smaller percentages of cells with aberrations than those developed earlier. It is suggested that this may be the result of competition between more damaged and less damaged cells during the development of the shoot. There is consequently a decrease of sterility in successive flowers. The numbers of karyotypes taking part in the formation of lower and uppermost flowers were estimated cytologically at 4, 8 and 12 Kr. It was found that more karyotypes were involved in the formation of the lower flowers than in the upper ones. It appeared that at lower doses larger numbers of karyotypes were taking part in the formation of the chimaera than at higher doses. (auth.)

  19. Micron-scale lens array having diffracting structures

    Science.gov (United States)

    Goldberg, Kenneth A

    2013-10-29

    A novel micron-scale lens, a microlens, is engineered to concentrate light efficiently onto an area of interest, such as a small, light-sensitive detector element in an integrated electronic device. Existing microlens designs imitate the form of large-scale lenses and are less effective at small sizes. The microlenses described herein have been designed to accommodate diffraction effects, which dominate the behavior of light at small length scales. Thus a new class of light-concentrating optical elements with much higher relative performance has been created. Furthermore, the new designs are much easier to fabricate than previous designs.

  20. Microbial contamination of contact lens storage cases and domestic tap water of contact lens wearers.

    Science.gov (United States)

    Üstüntürk, Miray; Zeybek, Zuhal

    2012-11-01

    Contact lenses have been widely used as an alternative to spectacles both in developed and developing countries. However, under certain circumstances, adverse responses can occur during contact lens wear and several microorganisms--including bacteria, fungi, and free living amoebae--can cause several eye infections in wearers. Extended wear of contact lenses is the major risk factor of eye infections such as microbial keratitis, besides contaminated contact lens storage case, contaminated lens care solutions, and inaccurate contact lens handling. In this study, we collected contact lens storage case and domestic tap water samples from 50 asymptomatic contact lens wearers. We determined that total aerobic mesophilic bacteria were isolated in 45 (90 %), Gram negative rod bacteria were isolated in 20 (40 %), Pseudomonas spp. were isolated in 2 (4 %) and fungi were isolated in 18 (36 %) out of 50 contact lens storage cases. Free living amoebae were not detected in investigated contact lens storage cases. At the same time, out of 50, total aerobic mesophilic bacteria were isolated in 34 (68 %), fungi were isolated in 15 (30 %) and free living amoebae were isolated in 15 (30 %) domestic tap water samples. No Gram-negative rod bacteria and Pseudomonas spp. were detected in investigated water samples. Two contact lens case samples and two tap water samples were excluded from the analysis for Pseudomonas spp. for technical reasons. According to our findings, inadequate contact lens maintenance during lens wear may result in the contamination of contact lens storage cases. This situation can lead to severe eye infections in contact lens wearers over time.

  1. A possible explanation for the observed tune shift on the 150GeV front porch at the Tevatron

    Energy Technology Data Exchange (ETDEWEB)

    Gelfand, Norman M.; /Fermilab

    2007-06-01

    It has been known that the tunes of the Tevatron drift on the 150 GeV front porch . The drift is observed to have the same time dependence as the drift in the chromaticity. The variation in the chromaticity is due to the change in the b{sub 2} of the superconducting dipoles, which represents the integrated sextupole moment of the magnet. It is reasonable to assume that the tune drift is due to the feed down from the changing b{sub 2}. Calculations based on this assumption, both here and in earlier attempts to explain the tune drift, show, absent unreasonable assumptions about the closed orbit, that the simple models of the variation of the sextupole moment will not explain the tune drift. An explanation, for both the tune drift and the tune split observed when the Tevatron was first operated, is proposed which is based on the longitudinal variation of the sextupole component in the dipoles and the fact that the dipoles are not perfect sector magnets.

  2. Search for squarks and gluinos in the D0 experiment of the Run-II-a at the Tevatron

    International Nuclear Information System (INIS)

    Verdier, P.

    2007-11-01

    The D0 experiment is recording pp-bar collisions at a center-of-mass energy of 1.96 TeV since the beginning of the Run II-a of the Tevatron in 2001. The design of processor boards for the D0 level 2 trigger system is first presented. Those boards were installed in 2003, and they have been working perfectly since that date. Performances of missing transverse energy (/ ET ) reconstruction are then described. This quantity is important at hadron colliders especially for new particles searches. Finally, squarks and gluinos, supersymmetric partners of quarks and gluons, could be the most copiously produced supersymmetric particles at the Tevatron, if they are sufficiently light. Those particles were searched for in 0.96 fb -1 of data recorded by D0 during the Run II-a. The final state consists of jets and missing transverse energy. The numbers of observed events are in good agreement with the Standard Model predictions. Lower mass limits at 95 % confidence level are obtained on the squark and gluino masses in the framework of the mSUGRA model. Contributions to other D0 data analyses are also shortly described. Those analyses are the search for first generation leptoquarks and the search for squarks in jets+τ(s)+E T events. The possibility to constrain a 'Little Higgs' model using the results of the jets+E T searches is then discussed. (author)

  3. Design for antiproton collection and beam transport in the Fermilab Tevatron I project

    Energy Technology Data Exchange (ETDEWEB)

    Colton, E.; Hojvat, C.

    1983-03-01

    120-GeV protons from the Main Ring will be used to produce 8-GeV antiprotons. A pulsed lithium lens collects and matches the antiprotons to a beam line for injection into the Debuncher Ring. The anti p beam has a transverse emittance of 20..pi.. mm-mr and a deltap/p = +-2.0%. The beam line consists of a clean-up section with vertical emittance selection, two long dispersion free sections, a bend and a vertical injector. Antiprotons with a transverse emittance of 2..pi.. mm-mr and deltap/p = +-7.0 x 10/sup -4/ are transported in the reverse direction, bypassing the target area, and along the 120-GeV proton transport line for reverse injection in the Main Ring.

  4. Contact lens compliance among a group of young, university-based lens users in South India.

    Science.gov (United States)

    Noushad, Babu; Saoji, Yeshwant; Bhakat, Premjit; Thomas, Jyothi

    2012-01-01

    To investigate the rate of compliance with the soft contact lens care and maintenance procedures with a focus on contact lens wearing habits, cleaning and disinfecting procedures, and maintenance of lens care accessories in a group of young, university-based contact lens wearers Two hundred and sixteen young soft contact lens wearers with an age range of 18-22 years were selected conveniently from the student population of Manipal University, Manipal, India. After receiving informed consent from the participants, their level of compliance with contact lenses was assessed using a questionnaire. The mean (±SD) age of the participants was 21.86±2.35 years. Out of 216 subjects, only 34% of the lens users were identified to be compliant with the least level of compliance observed in the maintenance of lens care accessories. Conventional users showed significantly (p=0.001) better level of compliance compared to disposable wearers and so did the users who acquired their lenses from clinicians (p=0.001) compared to over-the-counter lens receipt. The gender (p=0.496) and years of experience in contact lens use (p=0.142) did not show any statistically significant difference in the level of compliance. This study demonstrated that non-compliance with lens care procedures among a group of young, university-based soft contact lens wearers is common. The results indicated that all subjects had some degree of non-compliance and the least level of compliance observed in the care of lens accessories.

  5. Tear film physiology and contact lens wear. II. Contact lens-tear film interaction.

    Science.gov (United States)

    Holly, F J

    1981-04-01

    The successful fitting of contact lenses requires the practitioner to take into account many properties of the specific lens type used but the practitioner must also understand patient factors including tear properties, use of appropriate solutions, procedures for lens cleaning, and efficiency of blinking. Selection of appropriate patients, selection of lens type, proper fitting, good maintenance, and training and monitoring of patients increase the probability of achieving success.

  6. Placement of a crystalline lens and intraocular lens: Retinal image quality.

    Science.gov (United States)

    Siedlecki, Damian; Nowak, Jerzy; Zajac, Marek

    2006-01-01

    The influence of changes of both crystalline lens and intraocular lens (IOL) misalignment on the retinal image quality was investigated. The optical model of the eye used in investigations was the Liou-Brennan model, which is commonly considered as one of the most anatomically accurate. The original crystalline lens from this model was replaced with an IOL, made of rigid polymethylmethacrylate, in a way that recommend obligatory procedures. The modifications that were made both for crystalline lens and IOL were the longitudinal, the transversal, and the angular displacement.

  7. Restoring lens capsule integrity enhances lens regeneration in New Zealand albino rabbits and cats.

    Science.gov (United States)

    Gwon, A; Gruber, L J; Mantras, C

    1993-11-01

    In studies conducted by numerous investigators for 150 years, lenses regenerated following endocapsular lens extraction in New Zealand albino rabbits have been irregular in shape, appearing primarily doughnut-shaped as a result of lack of lens growth at the site of the anterior capsulotomy and its adhesion to the posterior capsule. In the present study, we restored the lens capsule integrity by inserting a collagen patch at the time of surgery to seal the anterior capsulotomy and to improve the shape and structure of the regenerated lenses. We then filled the capsule bag with air to prevent adhesions between the anterior and posterior capsule and maintain capsule tautness and shape. Lens regeneration was first noted as early as one to two weeks. Regenerated lens filled approximately 50% of the capsule bag at two weeks and 100% by five weeks. Subsequent growth was in the anterior-posterior direction and measured by A-scan biometry. Lens thickness increased by 0.3 mm per month. The regenerated lenses were spherical with normal cortical structure and a nuclear opacity. In conclusion, restoration of lens capsular integrity with a collagen patch following endocapsular lens extraction enhanced the shape, structure, and growth rate of the regenerated lenses. In addition, lens regeneration was shown to occur in two cats.

  8. Development of Fresnel lens for improvement of rear visibility; Shikai kojo Fresnel lens no kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    Iwamoto, K.; Sanada, C.; Tsukino, M. [Nissan Motor Co. Ltd., Tokyo (Japan)

    1997-10-01

    Fresnel lenses have been widely used to increase the visual field around vehicles for drivers. However, internal reflection in these lenses has been an obstacle in producing dear images. This internal glow is generated by incident light from an unexpected direction reflecting on the non-lens surface or radiating from the non-lens surface of the Fresnel lens. The cause of internal glow has been made dear combining louver film with the lens. The newly developed technology removes obstacles in producing dear images by reducing internal glow. 7 figs.

  9. Night Vision Goggles Objectives Lens Focusing Methodology

    National Research Council Canada - National Science Library

    Pinkus, Alan; Task, H. L

    2000-01-01

    ...: interpupillary distance, tilt, eye relief, height, eyepiece and objective lens focus. Currently, aircrew use a Hoffman 20/20 test unit to pre-focus their NVG objective lenses at optical infinity before boarding their aircraft...

  10. Contractual considerations in contact lens practice.

    Science.gov (United States)

    Classé, J G

    1986-03-01

    The use of forms in contact lens practice can save time, promote patient education, and reduce the opportunity for legal or economic disputes. The most commonly employed forms are those for contact lens fitting agreements, instructions for care and maintenance of lenses, prepaid service agreements, clinical investigations of investigatory lenses or solutions, and for extended wear patients. Sample forms are utilized for purposes of illustration.

  11. Evolution and the Calcite Eye Lens

    OpenAIRE

    Williams, Vernon L.

    2013-01-01

    Calcite is a uniaxial, birefringent crystal, which in its optically transparent form, has been used for animal eye lenses, the trilobite being one such animal. Because of the calcite birefringence there is a difficulty in using calcite as a lens. When the propagation direction of incoming light is not exactly on the c-axis, the mages blur. In this paper, calcite blurring is evaluated, and the non-blurring by a crystallin eye lens is compared to a calcite one.

  12. Acute lens-induced glaucomas: A review

    Directory of Open Access Journals (Sweden)

    Syed Shoeb Ahmad

    2017-02-01

    Full Text Available Lens-induced factors are important and common mechanisms causing acute elevation of intraocular pressure. While in most cases, the diagnosis and management are straight-forward, in others it is difficult and can lead to improper procedures, complications and poor visual outcomes. This review was done with the aim of studying the various types of lens-induced glaucomas, classifying them in an easy way to understand manner, their clinical features, current management and future possibilities.

  13. Acoustic lens for capacitive micromachined ultrasonic transducers

    Science.gov (United States)

    Chang, Chienliu; Firouzi, Kamyar; Park, Kwan Kyu; Sarioglu, Ali Fatih; Nikoozadeh, Amin; Yoon, Hyo-Seon; Vaithilingam, Srikant; Carver, Thomas; Khuri-Yakub, Butrus T.

    2014-08-01

    Capacitive micromachined ultrasonic transducers (CMUTs) have great potential to compete with traditional piezoelectric transducers in therapeutic ultrasound applications. In this paper we have designed, fabricated and developed an acoustic lens formed on the CMUT to mechanically focus ultrasound. The acoustic lens was designed based on the paraxial theory and made of silicone rubber for acoustic impedance matching and encapsulation. The CMUT was fabricated based on the local oxidation of silicon (LOCOS) and fusion-bonding. The fabricated CMUT was verified to behave like an electromechanical resonator in air and exhibited wideband response with a center frequency of 2.2 MHz in immersion. The fabrication for the acoustic lens contained two consecutive mold castings and directly formed on the surface of the CMUT. Applied with ac burst input voltages at the center frequency, the CMUT with the acoustic lens generated an output pressure of 1.89 MPa (peak-to-peak) at the focal point with an effective focal gain of 3.43 in immersion. Compared to the same CMUT without a lens, the CMUT with the acoustic lens demonstrated the ability to successfully focus ultrasound and provided a viable solution to the miniaturization of the multi-modality forward-looking endoscopes without electrical focusing.

  14. Acoustic lens for capacitive micromachined ultrasonic transducers

    International Nuclear Information System (INIS)

    Chang, Chienliu; Firouzi, Kamyar; Sarioglu, Ali Fatih; Nikoozadeh, Amin; Yoon, Hyo-Seon; Vaithilingam, Srikant; Carver, Thomas; Khuri-Yakub, Butrus T; Kyu Park, Kwan

    2014-01-01

    Capacitive micromachined ultrasonic transducers (CMUTs) have great potential to compete with traditional piezoelectric transducers in therapeutic ultrasound applications. In this paper we have designed, fabricated and developed an acoustic lens formed on the CMUT to mechanically focus ultrasound. The acoustic lens was designed based on the paraxial theory and made of silicone rubber for acoustic impedance matching and encapsulation. The CMUT was fabricated based on the local oxidation of silicon (LOCOS) and fusion-bonding. The fabricated CMUT was verified to behave like an electromechanical resonator in air and exhibited wideband response with a center frequency of 2.2 MHz in immersion. The fabrication for the acoustic lens contained two consecutive mold castings and directly formed on the surface of the CMUT. Applied with ac burst input voltages at the center frequency, the CMUT with the acoustic lens generated an output pressure of 1.89 MPa (peak-to-peak) at the focal point with an effective focal gain of 3.43 in immersion. Compared to the same CMUT without a lens, the CMUT with the acoustic lens demonstrated the ability to successfully focus ultrasound and provided a viable solution to the miniaturization of the multi-modality forward-looking endoscopes without electrical focusing. (paper)

  15. LENS: Science Scope and Development Stages

    Science.gov (United States)

    Vogelaar, R. Bruce

    2013-04-01

    The Low-Energy Neutrino Spectroscopy (LENS) experiment will resolve the solar metallicity question via measurement of the CNO neutrino flux, as well as test the predicted equivalence of solar luminosity as measured by photon versus neutrinos. The LENS detector uses charged-current interaction of neutrinos on Indium-115 (loaded in a scintillator, InLS) to reveal the complete solar neutrino spectrum. LENS's optically segmented 3D lattice geometry achieves precise time and spatial resolution and unprecedented background rejection and sensitivity for low-energy neutrino events. This first-of-a-kind lattice design is also suited for a range of other applications where high segmentation and large light collection are required (eg: sterile neutrinos with sources, double beta decay, and surface detection of reactor neutrinos). The physics scope, detector design, and logic driving the microLENS and miniLENS prototyping stages will be presented. The collaboration is actively running programs; building, operating, developing, and simulating these prototypes using the Kimballton Underground Research Facility (KURF). New members are welcome to the LENS Collaboration, and interested parties should contact R. Bruce Vogelaar.

  16. Commissioning of Fermilab's Electron Cooling System for 8-GeV Antiprotons

    CERN Document Server

    Nagaitsev, Sergei; Burov, Alexey; Carlson, Kermit; Gai, Wei; Gattuso, Consolato; Hu, Martin; Kazakevich, Grigory; Kramper, Brian J; Kroc, Thomas K; Leibfritz, Jerry; Prost, Lionel; Pruss, Stanley M; Saewert, Greg W; Schmidt, Chuck; Seletsky, Sergey; Shemyakin, Alexander V; Sutherland, Mary; Tupikov, Vitali; Warner, Arden

    2005-01-01

    A 4.3-MeV electron cooling system has been installed at Fermilab in the Recycler antiproton storage ring and is being currently commissioned. The cooling system is designed to assist accumulation of 8.9-GeV/c antiprotons for the Tevatron collider operations. This paper will report on the progress of the electron beam commissioning effort as well as on detailed plans of demonstrating the cooling of antiprotons.

  17. Tevatron combination of single-top-quark cross sections and determination of the magnitude of the Cabibbo-Kobayashi-Maskawa matrix element V.sub.tb./sub

    Czech Academy of Sciences Publication Activity Database

    Aaltonen, T.; Abazov, V. M.; Abbott, B.; Kupčo, Alexander; Lokajíček, Miloš; Lysak, R.

    2015-01-01

    Roč. 115, č. 15 (2015), "152003"-"152003-11" ISSN 0031-9007 Institutional support: RVO:68378271 Keywords : Batavia TEVATRON Coll * channel cross section * measured * CKM matrix * CDF * DZERO * 1960 GeV-cms Subject RIV: BF - Elementary Particles and High Energy Physics Impact factor: 7.645, year: 2015

  18. Simultaneous measurement of forward-backward asymmetry and top polarization in dilepton final states from tt¯ production at the Tevatron

    Czech Academy of Sciences Publication Activity Database

    Abazov, V. M.; Abbott, B.; Acharya, B.S.; Kupčo, Alexander; Lokajíček, Miloš

    2015-01-01

    Roč. 92, č. 5 (2015), "052007-1"-"052007-16" ISSN 1550-7998 Institutional support: RVO:68378271 Keywords : Batavia TEVATRON Coll * DZERO * analyzing power * transverse momentum dependence * rapidity dependence * calibration * correlation * background Subject RIV: BF - Elementary Particles and High Energy Physics Impact factor: 4.643, year: 2014

  19. Rare decays of B mesons and baryons at the Tevatron and the LHC

    Energy Technology Data Exchange (ETDEWEB)

    Volpi, Guido [Univ. of Siena (Italy)

    2008-07-01

    The experimental study of rare decays of hadrons containing the b quark has been a fertile ground for some time, and keeps being one of the most interesting subjects in high energy physics. It has improved our understanding of hadronic processes, and allows investigating various aspects of the Standard Model and searching for hints of physics beyond the Standard Model. Examples are the comparison of branching fractions of charmless modes with predictions of models, the constraints on CKM angles (B0 → π+π-, B → DK, with D in suppressed modes), the observation of purely leptonic modes (B± → τ±v), the recently established difference in ACP between B0 → K+π- and B± → K±π0, suspected to be a hint new physics. All of them came from a long and successful experimental activity with e+e- collisions at the Y(4S) resonance. With hadronic colliders now coming into play, the study of rare decays is reaching new heights. Given the high cross section for production of all kinds of B hadrons, the record luminosities now provided by the Tevatron collider, and the LHC program in view for the next years, there is the potential for a rich program of interesting new measurements, including even rarer modes as the Bs0 → μ+μ-, strongly suppressed in the standard model but very sensitive to many NP scenarios. The complexity of the hadronic collision environment, however, requires detectors with high precision and high quality tracking, and a trigger system capable of complex event selections at high rates. The CDF experiment, thanks to a fast trigger on impact parameter, has been able to reconstruct many rare B decays, including previously unobserved modes Bs0 → K+K- and Bs0 → K

  20. Electron caustic lithography

    Directory of Open Access Journals (Sweden)

    S. M. Kennedy

    2012-06-01

    Full Text Available A maskless method of electron beam lithography is described which uses the reflection of an electron beam from an electrostatic mirror to produce caustics in the demagnified image projected onto a resist–coated wafer. By varying the electron optics, e.g. via objective lens defocus, both the morphology and dimensions of the caustic features may be controlled, producing a range of bright and tightly focused projected features. The method is illustrated for line and fold caustics and is complementary to other methods of reflective electron beam lithography.

  1. Double deflection system for an electron beam device

    International Nuclear Information System (INIS)

    Parker, N.W.; Crewe, A.V.

    1978-01-01

    A double deflection scanning system for electron beam instruments is provided embodying a means of correcting isotropic coma, and anisotropic coma aberrations induced by the magnetic lens of such an instrument. The scanning system deflects the beam prior to entry into the magnetic lens from the normal on-axis intersection of the beam with the lens according to predetermined formulas and thereby reduces the aberrations

  2. Experimental observation of lens damage after low doses of γ-ray irradiation to rabbit eyes

    International Nuclear Information System (INIS)

    Tang Xicheng; Hu Chunzhi; Wang Huijun; Zeng Aiping

    2000-01-01

    Objective: To investigate and evaluate low dose γ-ray radiation induced lens damage. Methods: Both eyes of each rabbit were exposed to a single dose of 25 or 50 cGy γ-rays in two groups, respectively. Samples were examined by transmission electron microscopy (TEM) and slit lamp microscopy (SLM)after irradiation. Results: Three days after 25 and 50 cGy irradiation,the epithelial cells of lens equator al region showed marked swelling and many vacuoles formed in intercellular space and cytoplasm,and accompanied by increased multi-lamellar bodies. Five months after irradiation, SLM of both groups showed that the posterior sub-capsule cortex exhibited clusters of vacuoles; 11 months after 50 cGy irradiation,the posterior sub-capsule and deep cortex manifested marked cloudy opacities. Conclusion: Low doses of γ-ray (25 and 50 cGy) irradiation can markedly damage lens of rabbits

  3. Surface modification of fluorosilicone acrylate RGP contact lens via low-temperature argon plasma

    International Nuclear Information System (INIS)

    Yin Shiheng; Wang Yingjun; Ren Li; Zhao Lianna; Kuang Tongchun; Chen Hao; Qu Jia

    2008-01-01

    A fluorosilicone acrylate rigid gas permeable (RGP) contact lens was modified via argon plasma to improve surface hydrophilicity and resistance to protein deposition. The influence of plasma treatment on surface chemical structure, hydrophilicity and morphology of RGP lens was investigated by X-ray photoelectron spectrometer (XPS), contact angle measurements and scanning electron microscope (SEM), respectively. The contact angle results showed that the hydrophilicity of the contact lens was improved after plasma treatment. XPS results indicated that the incorporation of oxygen-containing groups on surface and the transformation of silicone into hydrophilic silicate after plasma treatment are the main reasons for the surface hydrophilicity improvement. SEM results showed that argon plasma with higher power could lead to surface etching

  4. Cellulose nanocrystal and poly[di(ethylene glycol) adipate] blend for tunable lens

    Science.gov (United States)

    Ko, Hyun-U.; Kim, Hyun Chan; Li, Yaguang; Kim, Sang Youn; Kim, Jaehwan

    2016-04-01

    In these days, consumer electronics and medical device for optical diagnosis are minimalized and mobilized. The focusing part is one of crucial parts of optical diagnosis systems to reduce the size and weight. Thus, demand for tunable lens that change the focus itself is increased. To meet the demand, many tunable lens has been studied by utilizing smart materials that responded under mechanical, magnetic, optical, thermal, chemical, electrical or electrochemical stimuli. This paper reports a cellulose nanocrystal (CNC) and poly[di(ethylene glycol) adipate] (PDEGA) blend that is able to respond under electromechanical stimulus. The preparation of CNC/PDEGA and its characterization are illustrated and its actuation behavior is tested . Because the material has high dielectric constant and high reflection index, it is good candidate material for tunable lens.

  5. Conceptual design of hollow electron lenses for beam halo control in the Large Hadron Collider

    CERN Document Server

    Stancari, Giulio; Valishev, Alexander; Bruce, Roderik; Redaelli, Stefano; Rossi, Adriana; Salvachua Ferrando, Belen

    2014-01-01

    Collimation with hollow electron beams is a technique for halo control in high-power hadron beams. It is based on an electron beam (possibly pulsed or modulated in intensity) guided by strong axial magnetic fields which overlaps with the circulating beam in a short section of the ring. The concept was tested experimentally at the Fermilab Tevatron collider using a hollow electron gun installed in one of the Tevatron electron lenses. Within the US LHC Accelerator Research Program (LARP) and the European FP7 HiLumi LHC Design Study, we are proposing a conceptual design for applying this technique to the Large Hadron Collider at CERN. A prototype hollow electron gun for the LHC was built and tested. The expected performance of the hollow electron beam collimator was based on Tevatron experiments and on numerical tracking simulations. Halo removal rates and enhancements of halo diffusivity were estimated as a function of beam and lattice parameters. Proton beam core lifetimes and emittance growth rates were check...

  6. Study on the surface of fluorosilicone acrylate RGP contact lens treated by low-temperature nitrogen plasma

    International Nuclear Information System (INIS)

    Ren Li; Yin Shiheng; Zhao Lianna; Wang Yingjun; Chen Hao; Qu Jia

    2008-01-01

    In order to improve the surface hydrophilicity of fluorosilicone acrylate rigid gas permeable (RGP) contact lens, low temperature nitrogen plasma was used to modify the lens surface. Effects of plasma conditions on the surface structures and properties were investigated. Results indicated that the surface hydrophilicity of RGP contact lens was significantly improved after treatment. X-ray photoelectron spectroscopy (XPS) results showed that the nitrogen element was successfully incorporated into the surface. Furthermore, some new bonds such as N-C=O, F - and silicate were formed on the lens surface after nitrogen plasma treatment, which could result in the improvement of the surface hydrophilicity. Scanning electronic microscope (SEM) results indicated that nitrogen plasma with moderate power could make the surface smoother in some degree, while plasma with higher power could etch the surface

  7. Dose conversion coefficients for photon exposure of the human eye lens

    International Nuclear Information System (INIS)

    Behrens, R; Dietze, G

    2011-01-01

    In recent years, several papers dealing with the eye lens dose have been published, because epidemiological studies implied that the induction of cataracts occurs even at eye lens doses of less than 500 mGy. Different questions were addressed: Which personal dose equivalent quantity is appropriate for monitoring the dose to the eye lens? Is a new definition of the dose quantity H p (3) based on a cylinder phantom to represent the human head necessary? Are current conversion coefficients from fluence to equivalent dose to the lens sufficiently accurate? To investigate the latter question, a realistic model of the eye including the inner structure of the lens was developed. Using this eye model, conversion coefficients for electrons have already been presented. In this paper, the same eye model-with the addition of the whole body-was used to calculate conversion coefficients from fluence (and air kerma) to equivalent dose to the lens for photon radiation from 5 keV to 10 MeV. Compared to the values adopted in 1996 by the International Commission on Radiological Protection (ICRP), the new values are similar between 40 keV and 1 MeV and lower by up to a factor of 5 and 7 for photon energies at about 10 keV and 10 MeV, respectively. Above 1 MeV, the new values (calculated without kerma approximation) should be applied in pure photon radiation fields, while the values adopted by the ICRP in 1996 (calculated with kerma approximation) should be applied in case a significant contribution from secondary electrons originating outside the body is present.

  8. Search for Leptoquarks Decaying to $\\mu$ + $X$ Meson with the D0 Detector at the Fermilab Tevatron Collider

    Energy Technology Data Exchange (ETDEWEB)

    Karmgard, Daniel John [Florida State U., SCRI

    1999-01-01

    We describe a search for the pair production of second generation leptoquarks that decay to muons plus other particles in 94 $pb^{-1}$ of data taken with the D0 detector at the Fermilab Tevatron (center-of-mass energy $\\sqrt{s}$ = 1.8 TeV) from 1993{96. The search places limits on the cross sections and mass of second generation leptoquarks for various branching ratios and couplings. For both scalar leptoquarks decaying into a muon and a quark the mass limit is 200 GeV/$c^2$ while for one scalar leptoquark decaying into a muon and a quark with the other scalar leptoquark decaying into a neutrino and a quark the mass limit is 160 GeV/$c^2$ at the 95% confidence level.

  9. A search for the Higgs boson in the zh channel with the D0 detector at the Fermilab Tevatron collider

    Energy Technology Data Exchange (ETDEWEB)

    Heinmiller, James Matthew [Univ. of Illinois, Chicago, IL (United States)

    2006-01-01

    This analysis describes a search for a standard model Higgs boson produced in association with a Z boson through the decay mode ZH → e+e-b$\\bar{b}$ in p$\\bar{p}$ collisions at √s = 1.96 TeV at the Fermilab Tevatron Collider. The data sample used in this analysis corresponds to 452 pb-1 of integrated luminosity accumulated with the D0 detector. Agreement between data and standard model predictions is observed. A 95% confidence level upper exclusion limit for the σ(p$\\bar{p}$ → ZH) x BR(H → b$\\bar{b}$) channel is set between 3.2-8.2 pb for Higgs masses of 105 to 145 GeV.

  10. Measurement of the inclusive isolated prompt photon production cross section at the Tevatron using the CDF detector

    Energy Technology Data Exchange (ETDEWEB)

    Deluca Silberberg, Carolina [Autonomous Univ. of Barcelona (Spain)

    2009-04-01

    In this thesis we present the measurement of the inclusive isolated prompt photon cross section with a total integrated luminosity of 2.5 fb-1 of data collected with the CDF Run II detector at the Fermilab Tevatron Collider. The prompt photon cross section is a classic measurement to test perturbative QCD (pQCD) with potential to provide information on the parton distribution function (PDF), and sensitive to the presence of new physics at large photon transverse momentum. Prompt photons also constitute an irreducible background for important searches such as H → γγ, or SUSY and extra-dimensions with energetic photons in the final state. The Tevatron at Fermilab (Batavia, U.S.A.) is currently the hadron collider that operates at the highest energies in the world. It collides protons and antiprotons with a center-of-mass energy of 1.96 TeV. The CDF and the D0 experiments are located in two of its four interaction regions. In Run I at the Tevatron, the direct photon production cross section was measured by both CDF and DO, and first results in Run II have been presented by the DO Collaboration based on 380 pb-1. Both Run I and Run II results show agreement with the theoretical predictions except for the low pTγ region, where the observed and predicted shapes are different. Prompt photon production has been also extensively measured at fixed-target experiments in lower pTγ ranges, showing excess of data compared to the theory, particularly at high xT. From an experimental point of view, the study of the direct photon production has several advantages compared to QCD studies using jets. Electromagnetic calorimeters have better energy resolution than hadronic calorimeters, and the systematic uncertainty on the photon absolute energy scale is smaller. Furthermore, the determination of the photon kinematics does not require the use of jet algorithms. However, the measurements using photons

  11. Self-similarity of jet production in pp and anti pp collisions at RHIC, Tevatron, and LHC

    International Nuclear Information System (INIS)

    Tokarev, M.V.; Dedovich, T.G.; Zborovsky, I.

    2012-01-01

    Self-similarity of jet production in pp and anti pp collisions is studied in the framework of z scaling. Inclusive jet transverse momentum distributions measured by the STAR Collaboration at RHIC, the CDF and D0 Collaborations at Tevatron, and the CMS and ATLAS Collaborations at LHC are analyzed. The experimental spectra are compared with next-to-leading order QCD calculations in p T and z presentations. It is shown that self-similar features of jet cross sections manifested by the z scaling give strong restriction on the scaling function ψ(z) at high z. New results on energy and angular independence and asymptotic behavior of ψ(z) are discussed. The obtained results are considered as confirmation of self-similarity of jet production, fractality of hadron structure, and locality of constituent interactions at small scales

  12. Matter-Antimatter Differences using Muons: D0 Result on anomalous Dimuon Charge Asymmetry using Full Tevatron Data Set

    CERN Multimedia

    CERN. Geneva

    2013-01-01

    We measure the inclusive single muon charge asymmetry and the like-sign dimuon charge asymmetry in p-pbar collisions using the full data set of 10.4 fb-1 collected with the D0 detector at the Fermilab Tevatron. The standard model predictions of the charge asymmetries induced by CP violation are small in magnitude compared to the current experimental precision, so non-zero measurements could indicate new sources of CP violation. The measurements differ from the standard model predictions of CP violation in these asymmetries with a significance of 3.6 standard deviations. These results are interpreted in a framework of B meson mixing within the CKM formalism to measure the relative width difference Delta Gamma_d / Gamma_d between the mass eigenstates of the B0 meson system, and the semileptonic charge asymmetries a_sl^d and a_sl^s of the B0 and B0_s mesons respectively.

  13. Acanthamoeba keratitis and contact lens wear.

    Science.gov (United States)

    Lindsay, Richard G; Watters, Grant; Johnson, Richard; Ormonde, Susan E; Snibson, Grant R

    2007-09-01

    Acanthamoeba keratitis is a rare but serious complication of contact lens wear that may cause severe visual loss. The clinical picture is usually characterised by severe pain, sometimes disproportionate to the signs, with an early superficial keratitis that is often misdiagnosed as herpes simplex virus (HSV) keratitis. Advanced stages of the infection are usually characterised by central corneal epithelial loss and marked stromal opacification with subsequent loss of vision. In this paper, six cases of contact lens-related Acanthamoeba keratitis that occurred in Australia and New Zealand over a three-year period are described. Three of the patients were disposable soft lens wearers, two were hybrid lens wearers and one was a rigid gas permeable lens wearer. For all six cases, the risk factors for Acanthamoeba keratitis were contact lens wear with inappropriate or ineffective lens maintenance and exposure of the contact lenses to tap or other sources of water. All six patients responded well to medical therapy that involved topical use of appropriate therapeutic agents, most commonly polyhexamethylene biguanide and propamidine isethionate, although two of the patients also subsequently underwent deep lamellar keratoplasty due to residual corneal surface irregularity and stromal scarring. Despite the significant advances that have been made in the medical therapy of Acanthamoeba keratitis over the past 10 years, prevention remains the best treatment and patients who wear contact lenses must be thoroughly educated about the proper use and care of the lenses. In particular, exposure of the contact lenses to tap water or other sources of water should be avoided.

  14. Electron spectrometer for gas-phase spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Bozek, J.D.; Schlachter, A.S. [Ernest Orlando Lawrence Berkeley National Lab., CA (United States)

    1997-04-01

    An electron spectrometer for high-resolution spectroscopy of gaseous samples using synchrotron radiation has been designed and constructed. The spectrometer consists of a gas cell, cylindrical electrostatic lens, spherical-sector electron energy analyzer, position-sensitive detector and associated power supplies, electronics and vacuum pumps. Details of the spectrometer design are presented together with some representative spectra.

  15. Very low energy scanning electron microscopy

    Czech Academy of Sciences Publication Activity Database

    Frank, Luděk; Hovorka, Miloš; Konvalina, Ivo; Mikmeková, Šárka; Müllerová, Ilona

    2011-01-01

    Roč. 645, č. 1 (2011), s. 46-54 ISSN 0168-9002 R&D Projects: GA MŠk OE08012 Institutional research plan: CEZ:AV0Z20650511 Keywords : scanning electron microscopy * low energy electrons * cathode lens * very low energy STEM * grain contrast Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 1.207, year: 2011

  16. A Measurement of the Cross-Section Ratio of the $W$ and $Z$ Electronic Decays and the Total Width of the $W$ with the D0 Detector

    Energy Technology Data Exchange (ETDEWEB)

    Tarazi, Jamal Nabil [UC, Irvine

    1997-01-01

    This dissertation reports on the measurement of the inclusive production cross sections of electronically decaying W and Z gauge bosons in $p\\bar{p}$ collisions at $\\sqrt{s}$ = 1:8 TeV. The data was collected by the D0 detector during the 1994-1996 collider run of the Fermilab Tevatron....

  17. Lens exposure during brain scans using multidetector row CT scanners: methods for estimation of lens dose.

    Science.gov (United States)

    Suzuki, S; Furui, S; Ishitake, T; Abe, T; Machida, H; Takei, R; Ibukuro, K; Watanabe, A; Kidouchi, T; Nakano, Y

    2010-05-01

    Some recent studies on radiation lens injuries have indicated much lower dose thresholds than specified by the current radiation protection guidelines. The purpose of this research was to measure the lens dose during brain CT scans with multidetector row CT and to assess methods for estimating the lens dose. With 8 types of multidetector row CT scanners, both axial and helical scans were obtained for the head part of a human-shaped phantom by using normal clinical settings with the orbitomeatal line as the baseline. We measured the doses on both eyelids by using an RPLGD during whole-brain scans including the orbit with the starting point at the level of the inferior orbital rim. To assess the effect of the starting points on the lens doses, we measured the lens doses by using 2 other starting points for scanning (the orbitomeatal line and the superior orbital rim). The CTDIvols and the lens doses during whole-brain CT including the orbit were 50.9-113.3 mGy and 42.6-103.5 mGy, respectively. The ratios of lens dose to CTDIvol were 80.6%-103.4%. The lens doses decreased as the starting points were set more superiorly. The lens doses during scans from the superior orbital rim were 11.8%-20.9% of the doses during the scans from the inferior orbital rim. CTDIvol can be used to estimate the lens dose during whole-brain CT when the orbit is included in the scanning range.

  18. Development of Powerhouse Using Fresnel lens

    Directory of Open Access Journals (Sweden)

    Al-Dohani Nawar Saif

    2018-01-01

    Full Text Available Solar energy is an alternative source of renewable energy. Sultanate of Oman government showed initiation on utilization of solar energy for domestic and industrial applications. Fresnel lens is one of the methods to collect maximum energy by gathering heat of the sun in the concentrated form (using solar collectors. Earlier research work discloses that Fresnel lens gave better result in terms of power output and produces lower heat loss as compared to linear –parabolic solar collectors. In this work, development of a proto Fresnel lens power house was made to generate electricity. The focused heat from Fresnel lens was used to heat the molten salt in a heat exchanger to produce the steam. The generated steam was used to rotate the steam engine coupled to a generator. In the current work, a maximum power of 30 W was produced. In addition, comparative study was carried out regarding solar salts and heat exchanger materials to understand the Fresnel powerhouse performance. Overall the present study gave valuable information regarding usage of Fresnel lens for electricity generation in Oman.

  19. Non-compliance in contact lens wear.

    Science.gov (United States)

    Claydon, B E; Efron, N

    1994-10-01

    Non-compliance is emerging as a critical issue in the contact lens field. This problem has been studied at depth in general health care situations and is seen as the responsibility of both practitioner and patient (client) working in a health care partnership. The contact lens practitioner and patient present a specific case for the study of non-compliance in areas such as hygiene, solution use, appointment attendance and wearing times. From 40 to 91% of contact lens patients have been reported as non-complaint in the use of recommended care and maintenance regimens and many of these are confused or ignorant about their behaviour. In order to arrive at a general set of conclusions from the studies published to date, it is important to understand the methodology of each study, it purpose, the definition of non-compliance used and the way the results were analysed and described. This review summarizes the research into non-compliance in the contact lens field to data. A set of general conclusions is drawn and a model for compliance in the context of contact lens practice is proposed.

  20. Spherical aberration in contact lens wear.

    Science.gov (United States)

    Lindskoog Pettersson, A; Jarkö, C; Alvin, A; Unsbo, P; Brautaset, R

    2008-08-01

    The aim of the present studies was to investigate the effect on spherical aberration of different non custom-made contact lenses, both with and without aberration control. A wavefront analyser (Zywave, Bausch & Lomb) was used to measure the aberrations in each subject's right eye uncorrected and with the different contact lenses. The first study evaluated residual spherical aberration with a standard lens (Focus Dailies Disposable, Ciba Vision) and with an aberration controlled contact lens (ACCL) (Definition AC, Optical Connection Inc.). The second study evaluated the residual spherical aberrations with a monthly disposable silicone hydrogel lens with aberration reduction (PureVision, Bausch & Lomb). Uncorrected spherical aberration was positive for all pupil sizes in both studies. In the first study, residual spherical aberration was close to zero with the standard lens for all pupil sizes whereas the ACCL over-corrected spherical aberration. The results of the second study showed that the monthly disposable lens also over-corrected the aberration making it negative. The changes in aberration were statistically significant (plenses. Since the amount of aberration varies individually we suggest that aberrations should be measured with lenses on the eye if the aim is to change spherical aberration in a certain direction.

  1. A lazy way to design infrared lens

    Science.gov (United States)

    Qiu, RongSheng; Wu, JianDong; Chen, LongJiang; Yu, Kun; Pang, HaoJun; Hu, BaiZhen

    2017-08-01

    We designed a compact middle-wave infrared (MWIR) lens with a large focal length ratio (about 1.5:1), used in the 3.7 to 4.8 μm range. The lens is consisted of a compact front group and a re-imaging group. Thanks to the compact front group configuration, it is possible to install a filter wheel mechanism in such a tight space. The total track length of the lens is about 50mm, which includes a 2mm thick protective window and a cold shield of 12mm. The full field of view of the lens is about 3.6°, and F number is less than 1.6, the image circle is about 4.6mm in diameter. The design performance of the lens reaches diffraction limitation, and doesn't change a lot during a temperature range of -40°C +60°C. This essay proposed a stepwise design method of infrared optical system guided by the qualitative approach. The method fully utilize the powerful global optimization ability, with a little effort to write code snippet in optical design software, frees optical engineer from tedious calculation of the original structure.

  2. Development of a Double-Gauss Lens Based Setup for Optoacoustic Applications.

    Science.gov (United States)

    Choi, Hojong; Ryu, Jae-Myung; Yeom, Jung-Yeol

    2017-03-03

    In optoacoustic (photoacoustic) systems, different echo signal intensities such as amplitudes, center frequencies, and bandwidths need to be compensated by utilizing variable gain or time-gain compensation amplifiers. However, such electronic components can increase system complexities and signal noise levels. In this paper, we introduce a double-Gauss lens to generate a large field of view with uniform light intensity due to the low chromatic aberrations of the lens, thus obtaining uniform echo signal intensities across the field of view of the optoacoustic system. In order to validate the uniformity of the echo signal intensities in the system, an in-house transducer was placed at various positions above a tissue sample and echo signals were measured and compared with each other. The custom designed double-Gauss lens demonstrated negligible light intensity variation (±1.5%) across the illumination field of view (~2 cm diameter). When the transducer was used to measure echo signal from an eye of a bigeye tuna within a range of ±1 cm, the peak-to-peak amplitude, center frequency, and their -6 dB bandwidth variations were less than 2 mV, 1 MHz, and 6%, respectively. The custom designed double-Gauss lens can provide uniform light beam across a wide area while generating insignificant echo signal variations, and thus can lower the burden of the receiving electronics or signal processing in the optoacoustic system.

  3. Characterization of lens based photoacoustic imaging system

    Directory of Open Access Journals (Sweden)

    Kalloor Joseph Francis

    2017-12-01

    Full Text Available Some of the challenges in translating photoacoustic (PA imaging to clinical applications includes limited view of the target tissue, low signal to noise ratio and the high cost of developing real-time systems. Acoustic lens based PA imaging systems, also known as PA cameras are a potential alternative to conventional imaging systems in these scenarios. The 3D focusing action of lens enables real-time C-scan imaging with a 2D transducer array. In this paper, we model the underlying physics in a PA camera in the mathematical framework of an imaging system and derive a closed form expression for the point spread function (PSF. Experimental verification follows including the details on how to design and fabricate the lens inexpensively. The system PSF is evaluated over a 3D volume that can be imaged by this PA camera. Its utility is demonstrated by imaging phantom and an ex vivo human prostate tissue sample.

  4. Freeform micromachining of an infrared Alvarez lens

    Science.gov (United States)

    Smilie, Paul J.; Dutterer, Brian S.; Lineberger, Jennifer L.; Davies, Matthew A.; Suleski, Thomas J.

    2011-02-01

    In 1967, Luis Alvarez introduced a novel concept for a focusing lens whereby two transmitting elements with cubic polynomial surfaces yield a composite lens of variable focal length with small lateral shifts. Computer simulations have demonstrated the behavior of these devices, but fabricating the refractive cubic surfaces of the types needed with adequate precision and depth modulation has proven to be challenging using standard methods, and, to the authors' knowledge, Alvarez lens elements have not been previously machined in infrared materials. Recent developments in freeform diamond machining capability have enabled the fabrication of such devices. In this paper, we discuss the fabrication of freeform refractive Alvarez elements in germanium using diamond micro-milling on a five-axis Moore Nanotech® 350FG Freeform Generator. Machining approaches are discussed, and measurements of surface figure and finish are presented. Initial experimental tests of optical performance are also discussed.

  5. Invited review article: the electrostatic plasma lens.

    Science.gov (United States)

    Goncharov, Alexey

    2013-02-01

    The fundamental principles, experimental results, and potential applications of the electrostatic plasma lens for focusing and manipulating high-current, energetic, heavy ion beams are reviewed. First described almost 50 years ago, this optical beam device provides space charge neutralization of the ion beam within the lens volume, and thus provides an effective and unique tool for focusing high current beams where a high degree of neutralization is essential to prevent beam blow-up. Short and long lenses have been explored, and a lens in which the magnetic field is provided by rare-earth permanent magnets has been demonstrated. Applications include the use of this kind of optical tool for laboratory ion beam manipulation, high dose ion implantation, heavy ion accelerator injection, in heavy ion fusion, and other high technology.

  6. 3D printed helical antenna with lens

    KAUST Repository

    Farooqui, Muhammad Fahad

    2016-12-19

    The gain of an antenna can be enhanced through the integration of a lens, however this technique has traditionally been restricted to planar antennas due to fabrication limitations of standard manufacturing processes. Here, with a unique combination of 3D and 2D inkjet printing of dielectric and metallic inks respectively, we demonstrate a Fresnel lens that has been monolithically integrated to a non-planar antenna (helix) for the first time. Antenna measurements show that the integration of a Fresnel lens enhances the gain of a 2-turn helix by around 4.6 dB giving a peak gain of about 12.9 dBi at 8.8 GHz.

  7. An "ESA-affordable" Laue-lens

    DEFF Research Database (Denmark)

    Lund, Niels

    2005-01-01

    With ESA's INTEGRAL mission gamma-ray astronomy has advanced to the point where major scientific advances must be expected from detailed studies of the many new point sources. The interest in developing focusing telescopes operating in the soft gamma-ray regime up to 1 MeV is therefore mounting r...... constraints of a specific medium size launch vehicle. The introduction of the lens mass as a primary design driver has some surprising effects for the choice of material for the crystals and new tradeoff considerations are introduced....... rapidly. Telescopes based on Laue diffraction of gamma-rays from crystals appear as one promising route, although the practical difficulties of realizing a large scale Laue lens are certainly not small. In this paper I have attempted to develop an optimized lens design considering the size and mass...

  8. Device for the radiation centering at electron emitters

    International Nuclear Information System (INIS)

    Panzer, S.; Ardenne, T. von; Jessat, K.; Bahr, G.

    1985-01-01

    The invention has been directed at a device for a simplified and reliable centering of electron beams at electron emitters in particular for welding and thermal surface modifications. The electron beam has been focussed relatively to an electron-optical lens. A movable masked electron detector has been arranged at the electron beam deflection plane. The electron detector is connected with an electronic data evaluation equipment

  9. The effectiveness of soft contact lens disinfection systems against Acanthamoeba on the lens surface.

    Science.gov (United States)

    Liedel, K K; Begley, C G

    1996-03-01

    This investigation compared the efficacy of three widely used contact lens disinfection systems against an ocular isolate of Acanthamoeba polyphaga. Twenty-seven worn Ciba NewVues lenses were quartered, heat sterilized and inoculated with Acanthamoeba. Lens quarters were then randomly assigned to three experimental groups, with Group A lenses exposed to cleaner and saline rinse only, Group B to disinfection only, and Group C to both cleaner and disinfection. One quarter of each lens served as a control and the other three quarters were experimental. Quantification of viable Acanthamoeba remaining on the lens was performed after each step of the disinfection process. Group A lenses showed no significant difference between the treatments, or the treatments and the control. Group B lenses demonstrated a significant difference (p = 0.0001) between the treatments and the control. In Group C (cleaning and disinfection), the control lens quarters were significantly different (p = 0.037) from the experimental group, but there was no significant difference between the treatments. All three disinfection regimens were very effective in reducing the number of viable Acanthamoeba on the contact lens surface. In the absence of proper cleaning (Group B), AOSept was the most effective of the three. These results also show the importance of thoroughly rubbing the contact lens surface to decrease the number of Acanthamoeba.

  10. Non-compliance with lens care and maintenance in diabetic contact lens wearers.

    Science.gov (United States)

    O'Donnell, Clare; Efron, Nathan

    2004-11-01

    We hypothesize that diabetic contact lens wearers may represent a special group displaying higher levels of compliance with their lens care regimens as a result of learned behaviour relating to maintenance of their diabetic condition. To test this hypothesis, a prospective, single centre, controlled, masked study was performed whereby 29 diabetic contact lens patients and 29 non-diabetic control subjects were issued with disposable hydrogel contact lenses and a multipurpose lens care regimen. All participants were given identical instruction on lens care and maintenance. Compliance levels were assessed at a 12-month aftercare appointment by demonstration and questionnaire. Twenty-four different aspects of compliance were scored, 12 by observation and 12 by questionnaire report, of which only two showed a significant difference between the diabetic and control groups. Although the combined population of contact lens wearers was generally compliant, there were examples of non-compliance in both groups. Neither the duration of diabetes nor the degree of metabolic control appeared to have a significant effect on compliance. The results suggest that eye care practitioners cannot assume that diabetic patients will be more compliant with contact lens care and maintenance than non-diabetic patients.

  11. Analytic models of plausible gravitational lens potentials

    International Nuclear Information System (INIS)

    Baltz, Edward A.; Marshall, Phil; Oguri, Masamune

    2009-01-01

    Gravitational lenses on galaxy scales are plausibly modelled as having ellipsoidal symmetry and a universal dark matter density profile, with a Sérsic profile to describe the distribution of baryonic matter. Predicting all lensing effects requires knowledge of the total lens potential: in this work we give analytic forms for that of the above hybrid model. Emphasising that complex lens potentials can be constructed from simpler components in linear combination, we provide a recipe for attaining elliptical symmetry in either projected mass or lens potential. We also provide analytic formulae for the lens potentials of Sérsic profiles for integer and half-integer index. We then present formulae describing the gravitational lensing effects due to smoothly-truncated universal density profiles in cold dark matter model. For our isolated haloes the density profile falls off as radius to the minus fifth or seventh power beyond the tidal radius, functional forms that allow all orders of lens potential derivatives to be calculated analytically, while ensuring a non-divergent total mass. We show how the observables predicted by this profile differ from that of the original infinite-mass NFW profile. Expressions for the gravitational flexion are highlighted. We show how decreasing the tidal radius allows stripped haloes to be modelled, providing a framework for a fuller investigation of dark matter substructure in galaxies and clusters. Finally we remark on the need for finite mass halo profiles when doing cosmological ray-tracing simulations, and the need for readily-calculable higher order derivatives of the lens potential when studying catastrophes in strong lenses

  12. Photonic crystal based polarization insensitive flat lens

    Science.gov (United States)

    Turduev, M.; Bor, E.; Kurt, H.

    2017-07-01

    The paper proposes a new design of an inhomogeneous artificially created photonic crystal lens structure consisting of annular dielectric rods to efficiently focus both transverse electric and transverse magnetic polarizations of light into the same focal point. The locations of each individual cell that contains the annular dielectric rods are determined according to a nonlinear distribution function. The inner and outer radii of the annular photonic dielectric rods are optimized with respect to the polarization insensitive frequency response of the transmission spectrum of the lens structure. The physical background of the polarization insensitive focusing mechanism is investigated in both spatial and frequency domains. Moreover, polarization independent wavefront transformation/focusing has been explored in detail by investigating the dispersion relation of the structure. Corresponding phase index distribution of the lens is attained for polarization insensitive normalized frequency range of a/λ  =  0.280 and a/λ  =  0.300, where a denotes the lattice constant of the designed structure and λ denotes the wavelength of the incident light. We show the wave transformation performance and focal point movement dynamics for both polarizations of the lens structure by specially adjusting the length of the structure. The 3D finite-difference time domain numerical analysis is also performed to verifiy that the proposed design is able to focus the wave regardless of polarization into approximately the same focal point (difference between focal distances of both polarizations stays below 0.25λ) with an operating bandwidth of 4.30% between 1476 nm and 1541 nm at telecom wavelengths. The main superiorities of the proposed lens structure are being all dielectric and compact, and having flat front and back surfaces, rendering the proposed lens design more practical in the photonic integration process in various applications such as optical switch

  13. Effect of infrared radiation on the lens

    Directory of Open Access Journals (Sweden)

    Aly Eman

    2011-01-01

    Full Text Available Background: Infrared (IR radiation is becoming more popular in industrial manufacturing processes and in many instruments used for diagnostic and therapeutic application to the human eye. Aim : The present study was designed to investigate the effect of IR radiation on rabbit′s crystalline lens and lens membrane. Materials and Methods: Fifteen New Zealand rabbits were used in the present work. The rabbits were classified into three groups; one of them served as control. The other two groups were exposed to IR radiation for 5 or 10 minutes. Animals from these two irradiated groups were subdivided into two subgroups; one of them was decapitated directly after IR exposure, while the other subgroup was decapitated 1 hour post exposure. IR was delivered from a General Electric Lamp model 250R 50/10, placed 20 cm from the rabbit and aimed at each eye. The activity of Na + -K + ATPase was measured in the lens membrane. Soluble lens proteins were extracted and the following measurements were carried out: estimation of total soluble protein, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE and Fourier transform infrared (FTIR spectroscopy. For comparison between multiple groups, analysis of variance was used with significance level set at P < 0.001. Results: The results indicated a change in the molecular weight of different lens crystalline accompanied with changes in protein backbone structure. These changes increased for the groups exposed to IR for 10 minutes. Moreover, the activity of Na + -K + ATPase significantly decreased for all groups. Conclusions: The protein of eye lens is very sensitive to IR radiation which is hazardous and may lead to cataract.

  14. Seeing with electrons

    International Nuclear Information System (INIS)

    Nellist, P.

    2006-01-01

    Commercially available lens correctors are extending the reach of electron microscopes to unprecedented atomic scales, as Peter Nellist describes. The electron microscope was invented in 1933 and is based on the principle that electrons have a wavelength that is inversely proportional to their momentum. There are two basic types: transmission electron microscopes and scanning electron microscopes, plus a hybrid of the two. The lenses in an electron microscope are provided by electromagnetic fields, but they suffer from spherical aberration. The addition of octupole and quadrupole corrector fields has improved the resolution of the electron microscope to better than 0.1 nm in the last decade. The next step is to correct for chromatic aberration, after which the resolution of the microscope will probably be limited by the size of the atom itself. (U.K.)

  15. The corneal stroma during contact lens wear.

    Science.gov (United States)

    Jalbert, Isabelle; Stapleton, Fiona

    2005-03-01

    Recent technological advances have lead to novel descriptions of the microanatomy of the corneal stroma. In the first section of this review, these findings and the role they play in the maintenance of vital properties such as corneal transparency, mechanical strength, homeostasis, wound-healing response and metabolism are described. In the second part, contact lens induced stromal alterations such as acidosis, oedema, striae, thinning and opacities are reviewed as well as the more recently described phenomenon of microdot deposits and keratocyte loss with an emphasis on how lens wearing stromal effects can be minimised.

  16. Sterilization potential of contact lens solutions

    Directory of Open Access Journals (Sweden)

    Dada Vijay

    1988-01-01

    Full Text Available In a dynamic field of Contact Lens Solutions maintenance of high standards of anti-microbial activity is a must Resterilization Activity Time′ is a universally accepted yardstick for such an evaluation. In this study eight brands of indigenous popular solutions alongwith two FDA approved solutions were tested for their sterilization efficacy: Standardized suspensions of Pseudomonas aeruginosa, Staphylococcus aureus, Candida albicans and Aspergillus fumigatus were used for the purpose. It was observed that the contact lens solutions available ir, the domestic market were not upto the mark Suggestions for improvement have also been made.

  17. Rotman lens for mm-wavelengths

    Science.gov (United States)

    Hall, Leonard T.; Hansen, Hedley J.; Abbott, Derek

    2002-11-01

    The 77 GHz band has been reserved for intelligent cruise control in luxury cars and some public transport services in America and the United Kingdom. The Rotman lens offers a cheap and compact means to extend the single beam systems generally used, to fully functional beam staring arrangements. Rotman lenses have been built for microwave frequencies with limited success. The flexibility of microstrip transmission lines and the advent of fast accurate simulation packages allow practical Rotman lenses to be designed at mm-wavelengths. This paper discusses the limitations of the conventional design approach and predicts the performance of a new Rotman lens designed at 77 GHz.

  18. Pulse transformer for the AA lithium lens

    CERN Document Server

    CERN PhotoLab

    1980-01-01

    The antiprotons emanating from the target were initially focused by a magnetic horn. Later on, a Li-lens was used during operation for the SPS collider, until 1992. A Li-rod (130 mm long, 34 mm in diameter) constituted the secondary of a 1:23 pulse-transformer. The half-sine pulse rose to 1000 kA in 900 microsec. The angular acceptance was 95 mrad. In operation after 1992, for LEAR only, a more modest Li-lens was used (155 mm long, diameter 20 mm, 480 kA, risetime 240 microsec, angular acceptance 75 mrad).

  19. Immunochemical analyses of soluble lens proteins in some marine fishes

    Digital Repository Service at National Institute of Oceanography (India)

    Menezes, M.R.

    Soluble eye lens proteins of 10 fishes, belonging to the families Clupeidae, Hemirhamphidae, Lactaridae, Scombridae, Stromatidae, Psettodidae, Bothidae and Soleidae were studied by immunoelectrophoresis using the lens antiserum of Sardinella...

  20. IOL Implants: Lens Replacement and Cataract Surgery (Intraocular Lenses)

    Science.gov (United States)

    ... Cataract Surgery vs. Laser-Assisted Cataract Surgery Cataract Vision Simulator Cataract Pictures and Videos: What Do ... Mar. 27, 2018 An intraocular lens (or IOL) is a tiny, artificial lens for the eye. It replaces the eye's ...

  1. Lens autofluorescence is not increased at high altitude

    DEFF Research Database (Denmark)

    Kessel, Line; Kofoed, Peter Kristian; Zubieta-Calleja, Gustavo

    2010-01-01

    PURPOSE: To study the relation between ambient environmental ultraviolet radiation exposure and lens fluorescence. METHODS: Non-invasive lens fluorometry measurements were compared in healthy Bolivian and Danish subjects. Background ultraviolet radiation was 4.5 times higher in Bolivia than in De...... living at sea level at 55 degrees northern latitude. These results suggest that lens ageing, as assessed by lens autofluorometry, is independent of exposure to ultraviolet radiation....

  2. Lens Subluxation after Plasmin and SF6 Injections in Rabbit Eyes

    Science.gov (United States)

    Wu, Wei-Chi; Liu, Chi-Hsien; Wang, Nan-Kai; Chen, Kwan-Jen; Chen, Tun-Lu; Hwang, Yih-Shiou; Liao, Pei-Ju; Li, Lien-Min; Lai, Chi-Chun

    2014-01-01

    Purpose To investigate the rate of lens subluxation following plasmin and/or SF6 injections in eyes, and whether a subsequent elevated level of vascular endothelial growth factor (VEGF) and vitreous tap would aggravate subluxation. Methods Four groups of rabbits were used. Group 1 received an intravitreal injection (IVI) of plasmin and SF6 in the right eye; group 2 received an IVI of plasmin in the right eye; group 3 received an IVI of SF6 in the right eye; and group 4 received an IVI of balanced salt solution in the right eye. After treatment, IVIs of VEGF were given and vitreous tap was performed three times, followed by clinical observation of lens subluxation and scanning electronic microscope evaluation of the zonular fibers. Results After IVIs of plasmin and SF6, and VEGF and vitreous tap had been performed one to three times, lens subluxation was noted in 0%, 43%, 71%, 71%, and 86% of the eyes in group 1. After IVIs of plasmin, VEGF, and vitreous tap had been performed one to three times, lens subluxation was noted in 11%, 22%, 44%, 44%, and 67% of the eyes in group 2. The eyes in group 3 and 4 did not show signs of lens subluxation after VEGF IVIs and vitreous tap. Histology confirmed zonular fiber damage in the eyes treated with plasmin. Conclusions The incidence of lens subluxation increased following plasmin injections in the eyes, and this was aggravated by the subsequent high VEGF level in the eyes and vitreous tapping. Zonular fibers were disrupted following plasmin treatment. These effects should be kept in mind when using plasmin enzymes in patients with vitreoretinal abnormalities. PMID:25397749

  3. Lens subluxation after plasmin and SF6 injections in rabbit eyes.

    Directory of Open Access Journals (Sweden)

    Wei-Chi Wu

    Full Text Available To investigate the rate of lens subluxation following plasmin and/or SF6 injections in eyes, and whether a subsequent elevated level of vascular endothelial growth factor (VEGF and vitreous tap would aggravate subluxation.Four groups of rabbits were used. Group 1 received an intravitreal injection (IVI of plasmin and SF6 in the right eye; group 2 received an IVI of plasmin in the right eye; group 3 received an IVI of SF6 in the right eye; and group 4 received an IVI of balanced salt solution in the right eye. After treatment, IVIs of VEGF were given and vitreous tap was performed three times, followed by clinical observation of lens subluxation and scanning electronic microscope evaluation of the zonular fibers.After IVIs of plasmin and SF6, and VEGF and vitreous tap had been performed one to three times, lens subluxation was noted in 0%, 43%, 71%, 71%, and 86% of the eyes in group 1. After IVIs of plasmin, VEGF, and vitreous tap had been performed one to three times, lens subluxation was noted in 11%, 22%, 44%, 44%, and 67% of the eyes in group 2. The eyes in group 3 and 4 did not show signs of lens subluxation after VEGF IVIs and vitreous tap. Histology confirmed zonular fiber damage in the eyes treated with plasmin.The incidence of lens subluxation increased following plasmin injections in the eyes, and this was aggravated by the subsequent high VEGF level in the eyes and vitreous tapping. Zonular fibers were disrupted following plasmin treatment. These effects should be kept in mind when using plasmin enzymes in patients with vitreoretinal abnormalities.

  4. Design and development of a high-concentration and high-efficiency photovoltaic concentrator using a curved Fresnel lens

    Energy Technology Data Exchange (ETDEWEB)

    Scharlack, R.S.; Moffat, A.

    1983-08-01

    Thermo Electron has designed a high concentration photovoltaic module that uses a domed, point-focus Fresnel lens. Their design, design optimization process, and results from lens and receiver tests are described in this report. A complete module has not been fabricated and probably will not be fabricated in the future; however, Thermo Electron's optical design, analysis, and testing of both secondary optical units and domed Fresnel lenses have made a significant contribution to our project. Tooling errors prevented the lens from reaching its potential efficiency by the end of the contract, and resolution of these tooling problems is currently being attempted with a follow-on contract, No. 68-9463.

  5. Analysis of H- ion trajectories in a space-charge lens

    International Nuclear Information System (INIS)

    Hess, G.R.; Humphries, S. Jr.

    1987-01-01

    The success of an electron, space-charge-corrected, solenoidal magnetic lens experiment encouraged the analysis of H - trajectories in a large model-corrected solenoid. With a confined distribution of low energy electrons, the selenoid magnetic flux surfaces define electric equipotential surfaces. The field contribution from trapped electrons cancel net axial electric fields. Negatively charged beam particles then experience a defocusing force which can alleviate spherical aberration. Regions of the magnetic field can be linked by individually biased potential rings to program the correcting electric field. Given a magnetic field distribution, the electric potential distribution required to numerically correct beam particle orbits can be used to determine these ring voltages. (orig.)

  6. 21 CFR 886.1420 - Ophthalmic lens gauge.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Ophthalmic lens gauge. 886.1420 Section 886.1420...) MEDICAL DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1420 Ophthalmic lens gauge. (a) Identification. An ophthalmic lens gauge is a calibrated device intended to manually measure the curvature of a...

  7. In vivo study of lens regeneration in Rana cyanophlyctis under ...

    African Journals Online (AJOL)

    SAM

    2014-03-12

    Mar 12, 2014 ... enhanced the percentage lens regeneration not only in young tadpoles but also in froglets. Lens regeneration ability ... Influence of vitamin A and ascorbic acid on lens regeneration in young, mature tadpoles and froglets of the frog Rana cyanophlyctis. Group .... ingested by macrophages. Dorsal iris cells ...

  8. 21 CFR 800.10 - Contact lens solutions; sterility.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Contact lens solutions; sterility. 800.10 Section...) MEDICAL DEVICES GENERAL Requirements for Specific Medical Devices § 800.10 Contact lens solutions... ophthalmic use, including contact lens solutions, should be sterile. It is further evident that such...

  9. Initial Experience With Posterior Chamber Intraocular Lens Implant ...

    African Journals Online (AJOL)

    The results of extracapsular cataract extraction with posterior chamber intraocular lens implant at the Jos University Teaching Hospital are reviewed. The results suggest that despite lack of facilities to calculate the lens power for emmetropia, the use of a standard lens of about 19.0D will provide a good number of our ...

  10. Search for the Production of Gluinos and Squarks with the CDF II Experiment at the Tevatron Collider

    Energy Technology Data Exchange (ETDEWEB)

    De Lorenzo, Gianluca [Autonomous Univ. of Barcelona (Spain)

    2010-05-19

    This thesis reports on two searches for the production of squarks and gluinos, supersymmetric partners of the Standard Model (SM) quarks and gluons, using the CDF detector at the Tevatron √s = 1.96 TeV p$\\bar{p}$ collider. An inclusive search for squarks and gluinos pair production is performed in events with large ET and multiple jets in the final state, based on 2 fb-1 of CDF Run II data. The analysis is performed within the framework of minimal supergravity (mSUGRA) and assumes R-parity conservation where sparticles are produced in pairs. The expected signal is characterized by the production of multiple jets of hadrons from the cascade decays of squarks and gluinos and large missing transverse energy ET from the lightest supersymmetric particles (LSP). The measurements are in good agreement with SM predictions for backgrounds. The results are translated into 95% confidence level (CL) upper limits on production cross sections and squark and gluino masses in a given mSUGRA scenario. An upper limit on the production cross section is placed in the range between 1 pb and 0.1 pb, depending on the gluino and squark masses considered. The result of the search is negative for gluino and squark masses up to 392 GeV/c2 in the region where gluino and squark masses are close to each other, gluino masses up to 280 GeV/c2 regardless of the squark mass, and gluino masses up to 423 GeV=c2 for squark masses below 378 GeV/c2. These results are compatible with the latest limits on squark/gluino production obtained by the D0 Collaboration and considerably improve the previous exclusion limits from direct and indirect searches at LEP and the Tevatron. The inclusive search is then extended to a scenario where the pair production of sbottom squarks is dominant. The new search is performed in a generic MSSM scenario with R-parity conservation. A specific SUSY particle mass hierarchy is assumed such that the

  11. Properties of Fiber Cell Plasma Membranes Isolated from the Cortex and Nucleus of the Porcine Eye Lens

    Science.gov (United States)

    Mainali, Laxman; Raguz, Marija; O’Brien, William J.; Subczynski, Witold K.

    2012-01-01

    The organization and physical properties of the lipid bilayer portion of intact cortical and nuclear fiber cell plasma membranes isolated from the eyes lenses of two-year-old pigs were studied using electron paramagnetic resonance (EPR) spin-labeling. Membrane fluidity, hydrophobicity, and the oxygen transport parameter (OTP) were assessed from the EPR spectra of precisely positioned spin labels. Intact cortical and nuclear membranes, which include membrane proteins, were found to contain three distinct lipid environments. These lipid environments were termed the bulk lipid domain, boundary lipid domain, and trapped lipid domain (lipids in protein aggregates). The amount of boundary and trapped lipids was greater in intact nuclear membranes than in cortical membranes. The properties of intact membranes were compared with the organization and properties of lens lipid membranes made of the total lipid extracts from the lens cortex or nucleus. In cortical lens lipid membranes, only one homogenous environment was detected, which was designated as a bulk lipid domain (phospholipid bilayer saturated with cholesterol). Lens lipid membranes prepared from the lens nucleus possessed two domains, assigned as a bulk lipid domain and a cholesterol bilayer domain (CBD). In intact nuclear membranes, it was difficult to discriminate the CBD, which was clearly detected in nuclear lens lipid membranes because the OTP measured in the CBD is the same as in the domain formed by trapped lipids. The two domains unique to intact membranes—namely, the domain formed by boundary lipids and the domain formed by trapped lipids—were most likely formed due to the presence of membrane proteins. It is concluded that formation of rigid and practically impermeable domains is enhanced in the lens nucleus, indicating changes in membrane composition that may help to maintain low oxygen concentration in this lens region. PMID:22326289

  12. Vitrectorhexis and lens aspiration with posterior chamber intraocular lens implantation in spherophakia.

    Science.gov (United States)

    Al-Haddad, Christiane; Khatib, Lama

    2012-07-01

    We describe a technique that uses the vitrector to perform successful lens aspiration and posterior chamber intraocular lens (IOL) implantation in children with spherophakia and anterior lens subluxation. After an anterior chamber maintainer is placed, the ocutome is introduced through a limbal incision to perform a circular vitrectorhexis to avoid excessive manipulation of the unstable lens followed by gentle cortex aspiration. A foldable IOL is injected into the sulcus (3-piece IOL) or bag (1-piece IOL) if the capsule is sufficiently stable. Through a pars plana incision, the ocutome is then used to perform a posterior capsulotomy to prevent late posterior capsule opacification. In our patient, sulcus IOL placement was more stable than in-the-bag placement. Neither author has a financial or proprietary interest in any material or method mentioned. Copyright © 2012 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  13. Solar powered desalination system using Fresnel lens

    Science.gov (United States)

    Sales, M. T. B. F.

    2016-11-01

    The Philippines is surrounded by coastal areas and these areas can be a potential source for potable water. This study aims to design and construct a solar powered desalination system using Fresnel lens. The experimental study was conducted using polluted salt water for the sample and desalination was carried out using the designed system. The desalination system was composed of the solar concentrator, solar still and the condenser system. The Fresnel lens was made of acrylic plastic and was an effective solar concentrator. Solar stills made of dark colored glass bottles were effective in absorbing the solar energy. The condenser system made of polybutylene and polystyrene were effective in condensing the vapor at ambient temperature. The shortest time of vaporization of the salt water was at 293 sec and the optimum angle of position of the lens was 36.42°. The amount of condensate collected was directly proportional to the amount of salt water in the solar still. The highest mean efficiency of the designed set-up was 34.82%. The water produced by the solar powered desalination system using Fresnel lens passed the standards set by WHO (World Health Organization) for drinking water.

  14. Surgical treatment of hereditary lens subluxations.

    Science.gov (United States)

    Ozdek, Sengul; Sari, Ayca; Bilgihan, Kamil; Akata, Fikret; Hasanreisoglu, Berati

    2002-01-01

    To evaluate the effectiveness and results of pars plana vitreolensectomy approach with transscleral fixation of intraocular lens in hereditary lens subluxations. Fifteen eyes of 9 consecutive patients with a mean age of 12.8+/-6.2 years (6-26 years) with hereditary lens subluxation were operated on and the results were evaluated in a prospective study. Surgery was considered if best spectacle corrected visual acuity (BSCVA) was less than 20/70. All eyes underwent a 2-port pars plana vitreolensectomy and transscleral fixation of an intraocular lens (IOL). The mean follow-up period was 12.6+/-7.5 months (6-22 months). There was no major intraoperative complication. Preoperatively, 8 eyes (53.3%) had a BSCVA of counting fingers (CF) and 7 eyes (46.6%) had a BSCVA of 20/200 to 20/70. Postoperatively, 14 eyes (93.3%) had a BSCVA of 20/50 or better. None of the patients had IOL decentration or intraocular pressure (IOP) increase during the follow-up period. There was a macular hole formation in 1 eye postoperatively. The early results of pars plana vitreolensectomy with IOL implantation using scleral fixation technique had shown that it not only promises a rapid visual rehabilitation but it is also a relatively safe method. More serious complications, however, may occur in the long term.

  15. READING SCRIPTURE THROUGH A MYSTICAL LENS

    African Journals Online (AJOL)

    Reading scripture through a mystical lens. 144 the illuminatory function of scripture which confirms and explains experience, rather than in its philological or scientific status. Elisabeth often juxtaposes several texts when quoting from memory and the biblical foundation of her writings is clearly evident in certain cases which ...

  16. Corneal ring infiltration in contact lens wearers

    Directory of Open Access Journals (Sweden)

    Seyed Ali Tabatabaei

    2017-01-01

    Full Text Available To report a case of atypical sterile ring infiltrates during wearing soft silicone hydrogel contact lens due to poor lens care. A 29-year-old woman presented with complaints of pain, redness, and morning discharge. She was wearing soft silicone hydrogel contact lens previously; her current symptoms began 1 week before presentation. On examination, best-corrected visual acuity was 20/40 in that eye. Slit-lamp examination revealed dense, ring-shaped infiltrate involving both the superficial and deep stromal layers with lucid interval to the limbus, edema of the epithelium, epithelial defect, and vascularization of the superior limbus. Cornea-specific in vivo laser confocal microscopy (Heidelberg Retina Tomograph 2 Rostock Cornea Module, HRT 2-RCM, Heidelberg Engineering GmbH, Dossenheim, Germany revealed Langerhans cells and no sign of Acanthamoeba or fungal features, using lid scraping and anti-inflammatory drops; her vision completely recovered. We reported an atypical case of a sterile corneal ring infiltrate associated with soft contact lens wearing; smear, culture, and confocal microscopy confirmed a sterile inflammatory reaction.

  17. The Search for physics beyond the standard model in the $B\\bar{B}$ spectrum observed in tevatron $p\\bar{p}$ collisions

    Energy Technology Data Exchange (ETDEWEB)

    Hoffman, Kara Dion [Purdue Univ., West Lafayette, IN (United States)

    1998-01-01

    Many extensions have been proposed to the Standard Model of fundamental particles and interactions, therefore we have conducted a general search with the Collider Detector at Fermilab (CDF) for particles which would be expected to appear as a resonance in the b$\\bar{b}$ mass spectrum produced in proton-antiproton collisions at a center-of-mass energy of √s = 1.8 TeV at the Fermilab Tevatron collider.

  18. FNAL R and D in medium energy electron cooling

    CERN Document Server

    Nagaitsev, S; Crawford, A C; Kroc, T; MacLachlan, J; Saewert, G; Schmidt, C W; Shemyakin, A; Warner, A

    2000-01-01

    The first stage of the Fermilab Electron Cooling R and D program is now complete: a technology necessary to generate hundreds of milliamps of electron beam current at MeV energies has been demonstrated. Conceptual design studies show that with an electron beam current of 200 mA and with a cooling section of 20 m electron cooling in the 8.9 GeV/c Fermilab Recycler ring can provide antiproton stacking rates suitable for the Tevatron upgrades beyond Run II luminosity goals. A novel electron beam transport scheme with a weak magnetic field at the cathode and in the cooling section, and with discrete focusing elements in between will be used. A prototype of such an electron cooling system is now being built at Fermilab as part of the continuing R and D program. This paper describes the status of the electron cooling R and D program at Fermilab.

  19. Search for a light Higgs boson in the channel WH→ eνe b anti b in p anti p collisions at √(s)=1.96 TeV at the DO detector of the Tevatron

    International Nuclear Information System (INIS)

    Meder-Marouelli, D.P.

    2005-01-01

    Although the standard model of particle physics has been very successfull in describing nature it needs to be extended by the Higgs mechanism to explain the particle masses observed in experiments. This mechanism introduces a new elementary particle called the Higgs boson. Current research at particle accelerators focuses on the search for the Higgs boson as a major goal. This analysis uses the data recorded with the D0-detector of the Tevatron at the Fermi National Accelerator Laboratory (FNAL). The Tevatron collides protons and antiprotons at a center of mass energy of √(s)=1.96 TeV. The primary goal of the analysis was the search for a light Higgs boson in the WH channel. For this the process p anti p→WH→eνb anti b was used. Furthermore a measurement of the Wb anti b production cross section has been performed. For the measurements a total integrated luminosity of L=255 pb -1 was available. For the selection of the desired processes events with electrons, missing transverse momentum and at least two jets have been used. At least two of the jets were required to be identified as b-jets. To obtain an efficient event selection many event properties had to be calculated and methods to cut on them needed to be optimized. Based on the selected events the Wb anti b production cross section has been calculated. After including the branching ratio BR(W→eν)=0.108 the result is σ(Wb anti b)=21.8 pb +15.5 -20.0 pb(sys+stat) for events where the b-quarks satisfy p T >8 GeV und η 95 (Wb anti b)=60.9 pb has been obtained. The same basic event selection has been used to obtain an upper limit for the WH production cross section. For the statistical analysis of these events the method of Cousins and Feldman was used. This method was extended to include background uncertainties as proposed by Conrad et al. Finally for a standard model Higgs boson of 115 GeV mass an upper limit for the production cross section of σ 95 (WH)=12.2 pb has been obtained at a confidence

  20. Intrinsic lens potential of neural retina inhibited by Notch signaling as the cause of lens transdifferentiation.

    Science.gov (United States)

    Iida, Hideaki; Ishii, Yasuo; Kondoh, Hisato

    2017-01-15

    Embryonic neural retinas of avians produce lenses under spreading culture conditions. This phenomenon has been regarded as a paradigm of transdifferentiation due to the overt change in cell type. Here we elucidated the underlying mechanisms. Retina-to-lens transdifferentiation occurs in spreading cultures, suggesting that it is triggered by altered cell-cell interactions. Thus, we tested the involvement of Notch signaling based on its role in retinal neurogenesis. Starting from E8 retina, a small number of crystallin-expressing lens cells began to develop after 20 days in control spreading cultures. By contrast, addition of Notch signal inhibitors to cultures after day 2 strongly promoted lens development beginning at day 11, and a 10-fold increase in δ-crystallin expression level. After Notch signal inhibition, transcription factor genes that regulate the early stage of eye development, Prox1 and Pitx3, were sequentially activated. These observations indicate that the lens differentiation potential is intrinsic to the neural retina, and this potential is repressed by Notch signaling during normal embryogenesis. Therefore, Notch suppression leads to lens transdifferentiation by disinhibiting the neural retina-intrinsic program of lens development. Copyright © 2016 Elsevier Inc. All rights reserved.