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Sample records for antiproton ring lear

  1. LEAR (Low Energy Antiproton Ring), general view.

    CERN Multimedia

    1990-01-01

    When the Antiproton Project was launched in the late 1970s, it was recognized that in addition to the primary purpose of high-energy proton-antiproton collisions in the SPS, there was interesting physics to be done with low-energy antiprotons. In 1982, LEAR was ready to receive antiprotons from the Antiproton Accumulator (AA), via the PS. A year later, delivery of antiprotons to the experiments began, at momenta as low as 100 MeV/c (kinetic energy 5.3 MeV), in an "Ultra-Slow Extraction" mode, dispensing some E9 antiprotons over times counted in hours. For such an achievement, stochastic and electron cooling had to be brought to high levels of perfection.

  2. LEAR: antiproton extraction lines

    CERN Multimedia

    Photographic Service

    1992-01-01

    Antiprotons, decelerated in LEAR to a momentum of 100 MeV/c (kinetic energy of 5.3 MeV), were delivered to the experiments in an "Ultra-Slow Extraction", dispensing some 1E9 antiprotons over times counted in hours. Beam-splitters and a multitude of beam-lines allowed several users to be supplied simultaneously.

  3. Physics with antiprotons at LEAR

    International Nuclear Information System (INIS)

    The low energy antiproton ring LEAR started to work at CERN in 1983. It provides clean anti p beams of much higher intensity and much better quality than available so far in the range from 0.1 to 2 GeV/c momentum. 16 of the 17 accepted experiments are installed and 14 of them took first data in 1983. After approx.= 240 hours of LEAR operation very first results are available. One can expect that exciting physics results be produced in many different domains provided LEAR gets enough anti p in the future. (orig.)

  4. The Low Energy Antiproton Ring (LEAR) in its first year of operation

    CERN Multimedia

    1983-01-01

    LEAR*) and its enclosure in the PS South Hall in 1983 shortly after the start of its particle physics programme. Visible (in red) are the 90 degree bending magnets consisting of 6 blocks each. Separated from the magnets by short straight sections are the quadrupole doublets (blue with read end-plates). The 4 long straight sections house large equipment like septa for injection/ejection, RF-cavities and later (since 1986) electron cooling and an internal target and its associated detector (JETSET experiment). Several small copper tubes spanning across the ring are coaxial lines transmitting the stochastic cooling signals from pickup to kicker. *)[see H.Koziol and D. Möhl, Phys. Rep. 403-404 (2004), p.271 and references therein

  5. The Low Energy Antiproton Ring (LEAR) some months before the start of its particle physics programme

    CERN Multimedia

    1983-01-01

    LEAR [see e.g.: H.Koziol and D. Möhl, Phys. Rep. 403-404 (2004), p.271 and references therein] and its enclosure in the PS South Hall in Jan, 1983, 4 months before the start of its particle physics programme. Visible (in red) are the 90 degree bending magnets consisting of 6 blocks each. Separated from the magnets by short straight sections are the quadrupole doublets (blue with read end-plates). The 4 long straight sections house large equipment like septa for injection/ejection, RF-cavities and later (since 1986) electron cooling and an internal target and its associated detector (JETSET experiment). Two small copper tubes spanning across the ring are coaxial lines transmitting the stochastic cooling signals from pick up to kicker. (see also photos 8205747X, 8207133, 8207541X, 8301550X,8309026X)

  6. The Low Energy Antiproton Ring (LEAR) some months before the start of its particle physics programme

    CERN Multimedia

    1983-01-01

    LEAR*)and its enclosure in the PS South Hall in Jan, 1983, 4 months before the start of its particle physics programme. Visible (in red) are the 90 degree bending magnets consisting of 6 blocks each. Separated from the magnets by short straight sections are the quadrupole doublets (blue with read end-plates). The 4 long straight sections house large equipment like septa for injection/ejection, RF-cavities and later (since 1986) electron cooling and an internal target and its associated detector (JETSET experiment). Two small copper tubes spanning across the ring are coaxial lines transmitting the stochastic cooling signals from pickup to kicker. (see also photos 8205747X, 8207133, 8207541X, 8309026) *)see e.g.: H.Koziol and D. Möhl, Phys. Rep. 403-404 (2004), p.271 and references therein

  7. Low Energy Antiproton Ring experimental area

    CERN Multimedia

    1991-01-01

    The experimental area at the Low Energy Antiproton Ring (LEAR) is seen. This set up was used to slow down antiprotons which had been produced by colliding a proton beam with a solid target. The experiments in the hall then took antiprotons from LEAR to perform antimatter studies. One such experiment, PS210, produced the world's first antihydrogen atoms.

  8. Professor Walter Oelert, leader of the team which created the first atoms of antihydrogen at the Low Energy Antiproton Ring (LEAR) in January 1996

    CERN Multimedia

    Laurent Guiraud

    1996-01-01

    Antiparticles were predicted in the work of Paul Dirac in the 1920's, since when physicists have identified all the necessary antiparticle constituents of an antiparticle atom - antielectrons (positrons), antiprotons and antineutrons. However, an antihydrogen atom wasn't produced until the PS210 experiment at CERN in 1995. PS210 used the LEAR accelerator, which was then nearing the end of its lifetime, so everything in the experiment had to work first time. After installing the equipment in spring 1995, the experiment took place in the autumn, in two hour periods over 4 weeks. The experiment team collided energetic antiprotons from LEAR with a heavy element, a challenge for them as well as the LEAR operators. Proving that antihydrogen atoms had been formed required several more weeks of data analysis, but the announcement that nine antihydrogen atoms had been produced came on 4 January 1996.

  9. A search for the ξ(2230) resonance in the bar p p → KsKs channel at LEAR [Low Energy Antiproton Ring

    International Nuclear Information System (INIS)

    Seventeen measurements of differential and total cross sections of the bar pp → KsKs reaction in the antiproton momentum range of 1.30 GeV/c to 1.57 GeV/c are presented. Most of these measurements are centered around the mass of the ξ(2230) resonance first seen in the K+K- and KsKs channel of the radiative decay of the J/Ψ by the MARK III collaboration at SLAC. The trajectories of the charged decay products of the Ks particles are recorded by two stacks of drift chambers and a set of plastic streamer tube planes. The bar pp → KsKs → π+π-π+π- events are reconstructed by a computer program and undergo a full kinematic fitting. A branching ratio upper limit, BR(bar pp → ξ)·BR(ξ → KsKs), on the presence of the resonance is calculated. The experiment was performed by the PS185 collaboration at the Low Energy Antiproton Ring (LEAR) at CERN

  10. Hyperon production with antiprotons at LEAR

    CERN Document Server

    Franz, J

    1997-01-01

    Recent results from the experiment PS185 at LEAR/CERN on the production of antihyperon-hyperon (YY) pairs are reported. An overview is given for the observables sigma , d sigma /dt, P, C/sub ij/ and S/sub F/ in the channel pp to Lambda Lambda . The results are compared with other measured antihyperon-hyperon pairs: Sigma /sup 0/ Lambda +c.c., Sigma /sup +/ Sigma /sup +/ and Sigma /sup -/ Sigma /sup $/. (7 refs).

  11. Symposium on Highlights from 14 years of LEAR Physics: "Light Antiprotonic Atoms" by R. Hayano

    CERN Multimedia

    1998-01-01

    Symposium on Highlights from 14 years of LEAR Physics hold at CERN, commemorating the closure of LEAR and giving a topical review of the impact of experiments with low energy antiprotons in their respective fields

  12. Antiproton trapping in various helium media: report of the HELIUMTRAP experiment at LEAR

    International Nuclear Information System (INIS)

    HELIUMTRAP (PS205) investigates the recently discovered anomalously long-lived states of antiprotons in various helium media. An overview is given of experiments stopping antiprotons in several phases of helium performed at LEAR in the last two years. (author)

  13. Symposium on Highlights from 14 years of LEAR Physics : "Antiproton Mass" by G. Gabrielse

    CERN Multimedia

    1998-01-01

    Symposium on Highlights from 14 years Physics hold at CERN, commemorating the closure of LEAR and giving a topical review of the impact of experiments with low energy antiprotons in their respective fields

  14. LEAR nearing completion

    CERN Multimedia

    1982-01-01

    In April 1982, all essential components of the Low Energy Antiproton Ring (LEAR) were in place, dry-tests of the individual systems could begin. See 9007366 for a more detailed description. See also 8201061, 8207133, 8309026.

  15. Golden Jubilee photos: LEAR

    CERN Multimedia

    2004-01-01

    Extraction lines that carried the antiprotons from LEAR to the experiments. Beam-splitters and a multitude of beam-lines allowed several users to be supplied simultaneously. Particle physicists don't always need ever more powerful accelerators to study interesting physics. LEAR, the Low Energy Antiproton Ring, was designed to help explore the properties of antimatter, with the annihilation of protons and antiprotons becoming the main theme. LEAR was commissioned in 1983 and contributed to more than 30 experiments with great success. LEAR took part in the discovery of a 'glueball', a particle composed entirely of gluons, the carriers of the strong nuclear force. LEAR also observed that neutral kaons and antikaons decay at a slightly different rate, offering physicists another insight into the mystery about why matter prevails over antimatter in the Universe. Uniquely, LEAR combined both the electron and stochastic beam cooling techniques, used to control and refine the beams. It also pioneered a technique usin...

  16. Physics with antiprotons at LEAR in the ACOL ERA. Proceedings of the 3. LEAR Workshop

    Energy Technology Data Exchange (ETDEWEB)

    Gastaldi, U.; Klapisch, R.; Richard, J.M.; Tran Thanh Van, J. (eds.)

    1985-01-01

    The programme covered the following topics: accelerator aspects (anti-p production, LEAR, advanced developments, cooling, LEAR design inspired machines). Nucleon antinucleon interactions (panti-p atom, scattering, annihilation, spin effects, antineutron physics, antibaryon physics). Spectroscopy (light mesons, hybrids, glueballs, baryonia, quarkonia). Rare channels (form factors, CP, CPT, C, T violation, quantum mechanics tests) anti-p nucleus interactions (exotic atoms, scattering, annihilation, hypernuclei). New ideas (antigravity, high precision experiments). New detectors (new experiments, general and/or technical aspects).

  17. LEAR is dead, long live LEIR!

    CERN Multimedia

    2004-01-01

    The LEAR (Low Energy Antiproton Ring) experiment has now been dismantled. Only the dipoles remain for use in the future LEIR (Low Energy Ion Ring) experiment, the new ring which will supply lead ions to the LHC experiments.

  18. LEAR during its first year of operation

    CERN Multimedia

    1983-01-01

    Construction of the Low Energy Antiproton Ring (LEAR) had been completed in July 1982, followed by tests with protons and antiprotons on machine properties, acceleration, deceleration and stochastic cooling. At the beginning of 1983, LEAR hardware was brought to operational level, and in July 1983 the first antiprotons were delivered to the experiments. See 8207133 for completion and start-up and 9007366 for a more detailed description. See also 8201061, 8204131.

  19. LEAR, shown here dismantled, will live to see another golden era as LEIR starting in 2005.

    CERN Multimedia

    Maximilien Brice

    2004-01-01

    The LEAR (Low Energy Antiproton Ring) experiment has now been dismantled. Only the dipoles remain for use in the future LEIR (Low Energy Ion Ring) experiment, the new ring which will supply lead ions to the LHC experiments.

  20. Study of X-Ray and $\\gamma$-Ray Spectra from Antiprotonic Atoms at the Slowly Extracted Antiproton Beam of LEAR

    CERN Multimedia

    2002-01-01

    This experiment will study the X-ray spectra of antiprotonic atoms and the $\\gamma$ spectra of residual nuclei after the antiproton absorption. We intend to begin with measurements on selected isotopically pure targets. Strong interaction effects, the antiproton absorption and the atomic cascade are analysed through the measurement of energies, lineshapes, relative and absolute intensities of all observable lines. The experiments are continued to determine st in resolved fine structure levels and in different isotopes of the same element. Coincidence techniques may be applied. All components of the experimental set-up are already existing from previous experiments and we could begin the measurements with any slowly extracted beam of low energy at LEAR.

  1. In the LEAR control room

    CERN Multimedia

    1983-01-01

    View into the control room of the Low Energy Antiproton Ring (LEAR). Edgar Asseo (sitting) and Dieter Möhl and Georges Carron reflecting upon some beam dynamics (or hardware?) problem. Vassilis Agoritsas, in the background, leaning over a plan or a keyboard. LEAR in its early years (1982 to about 1990) was run from this local control room in building 363 close to the end of the PS South Hall, where the ring was installed. Later-on the operation was surveyed from the PS main control room.

  2. Symposium on Highlights from 14 years of LEAR Physics : "LEAR Performance" by M. Chanel

    CERN Multimedia

    1998-01-01

    Symposium on Highlights from 14 years of LEAR Physics hold at CERN, commemorating the closure of LEAR and giving a topical review of the impact of experiments with low energy antiprotons in their respective fields: M. Chanel "LEAR Performance"

  3. LEAR's physics legacy

    CERN Multimedia

    Philippe Bloch

    2012-01-01

    By providing an intense and clean source of antiprotons for the first time, LEAR has opened many fields of research. Although it is not easy to summarise its versatile physics programme in a few lines, this article is an attempt to do justice to the 27 experiments performed during 14 years of running and to their successful results.   LEAR complex, September 1983. In the early days of LEAR operation, the antiproton intensity was quite limited and the machine was mostly used for studying antiprotonic atoms and interactions of low-energy antiprotons with nuclei. Physicists were also performing measurements of cross-sections (total, elastic, charge exchange) as a function of the antiproton momentum. These first experiments provided valuable insights into the properties of nucleon-antinucleon interactions, including their spin structure, and ruled out the existence of hypothesized multiquark states of matter referred to as “baryonium”. The ASTERIX experiment...

  4. LEAR: a machine ahead of its time

    CERN Multimedia

    Katarina Anthony

    2012-01-01

    Described as a “machine physicist's concert platform”, the Low Energy Antiproton Ring (LEAR) was everything at once: an accelerator, a storage ring, a decelerator, a cooler ring and a beam stretcher. 2012 marks the 30th anniversary of its start-up and an opportunity for the Bulletin to take a look back at the history of this remarkable machine.   This article is a tribute to Dieter Möhl, one of LEAR's founding fathers, who passed away at the end May.   Kilian's graph shows the phase space density of antiprotons produced from 26 GeV protons vs. antiproton momentum. Note that this density is significantly higher at low momentum for a decelerated beam. (Graph published in the 1977 "Low Energy Antiproton Factory" paper.) Like most great CERN projects, LEAR began with a dream and a coffee between colleagues. The year was 1976, the coffee was shared by Kurt Kilian and Diete...

  5. LEAR construction completed

    CERN Multimedia

    1982-01-01

    In July 1982, LEAR construction was completed, the individual systems had been dry-tested. On 16 July, the first 50 MeV (309 MeV/c) protons from Linac 1 were injected and circulated. On 11 October, the first antiprotons from the AA, decelerated in the PS to 609 MeV/c, were injected. Also in 1982, acceleration, deceleration and stochastic cooling were successfully tested. See 9007366 for a more detailed description. See also 8201061, 8204131, 8309026.

  6. CERN accelerator school: Antiprotons for colliding beam facilities

    International Nuclear Information System (INIS)

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

  7. Symposium on Highlights from 14 years of LEAR Physics : "Nuclear Physics" by T. von Egidy

    CERN Multimedia

    1998-01-01

    Symposium on Highlights from 145 years of LEAR Physics hold at CERN, commemorating the closure of LEAR and giving a topical review of the impact of experiments with low energy antiprotons in their respective fields

  8. Symposium on Highlights from 14 years of LEAR Physics : "Meson spectroscopy" by H. Koch

    CERN Multimedia

    1998-01-01

    Symposium on Highlights from 14 years of LEAR Physics hold at CERN, commemorating the closure of LEAR and giving a topical review of the impact of experiments with low energy antiprotons in their respective fields

  9. Symposium on Highlights from 14 years of LEAR Physics : "Annihilation in Flight" by D. Hertzog

    CERN Multimedia

    1998-01-01

    Symposium on Highlights from 14 years of LEAR Physics hold at CERN, commemorating the closure of LEAR and giving a topical review of the impact of experiments with low energy antiprotons in their respective fields

  10. Symposium on Highlights from 14 years of LEAR Physics : R. Landua (chairman)

    CERN Multimedia

    1998-01-01

    Symposium on Highlights from 14 years of LEAR Physics hold at CERN, commemorating the closure of LEAR and giving a topical review of the impact of experiments with low energy antiprotons in their respective fields

  11. Symposium on Highlights from 14 years of LEAR Physics : "Annihilation at Rest" by U. Gastaldi

    CERN Multimedia

    1998-01-01

    Symposium on Highlights from 14 years of LEAR Physics hold at CERN, commemorating the closure of LEAR and giving a topical review of the impact of experiments with low energy antiprotons in their respective fields

  12. Symposium on Highlights from 14 years of LEAR Physics : "AD Project" by S. Maury

    CERN Multimedia

    1998-01-01

    Symposium on Highlights from 14 years of LEAR Physics hold at CERN, commemorating the closure of LEAR and giving a topical review of the impact of experiments with low energy antiprotons in their respective fields: S. Maury "AD Project"

  13. Antiprotons

    Science.gov (United States)

    Chamberlain, Owen; Segre, Emilio; Wiegand, Clyde

    1955-11-29

    Since the development of Dirac's theory of the electron and the brilliant confirmation of one of its most startling predictions by the discovery of the positron by Anderson, it has been assumed most likely that the proton would also have its charge conjugate, the antiproton. The properties that define the antiproton are: (a) charge equal to the electron charge (also in sign); (b) mass equal to the proton mass; (c) stability against spontaneous decay; (d) ability to annihilate by interaction with a proton or neutron, probably generating pions and releasing in some manner the energy 2 mc{sup 2}; (e) generation in pairs with ordinary nucleons; (f) magnetic moment equal but opposite to that of the proton; (g) fermion of spin 1/2. Not all these properties are independent, but all might ultimately be subjected to experiment.

  14. The CERN Antiproton Collider Programme Accelerators and Accumulation Rings

    CERN Document Server

    Koziol, Heribert

    2004-01-01

    One of CERN's most daring and successful undertakings was the quest for the intermediate bosons, W and Z. In this paper, we describe the accelerator part of the venture which relied on a number of innovations: an extension of the budding method of stochastic cooling by many orders of magnitude; the construction of the Antiproton Accumulator, depending on several novel accelerator methods and technologies; major modifications to the 26 GeV PS Complex; and the radical conversion of the 300 GeV SPS, which just had started up as an accelerator, to a protonâ€"antiproton collider. The SPS Collider had to master the beamâ€"beam effect far beyond limits reached ever before and had to function in a tight symbiosis with the huge detectors UA1 and UA2.

  15. Non-Gaussian beam dynamics in low energy antiproton storage rings

    Science.gov (United States)

    Resta-López, J.; Hunt, J. R.; Welsch, C. P.

    2016-10-01

    In low energy antiproton facilities, where electron cooling is fundamental, the cooling forces together with heating phenomena causing emittance blow-up, such as Intra Beam Scattering (IBS), result in highly non-Gaussian beam distributions. In these cases, a precise simulation of IBS effects is essential to realistically evaluate the long term beam evolution, taking into account the non-Gaussian characteristics of the beam. Here, we analyse the beam dynamics in the Extra Low ENergy Antiproton ring (ELENA), which is a new small synchrotron currently being constructed at CERN to decelerate antiprotons to energies as low as 100 keV. Simulations are performed using the code BETACOOL, comparing different models of IBS.

  16. Antiprotonic-hydrogen atoms

    International Nuclear Information System (INIS)

    Experimental studies of antiprotonic-hydrogen atoms have recently made great progress following the commissioning of the low energy antiproton facility (LEAR) at CERN in 1983. At the same time our understanding of the atomic cascade has increased considerably through measurements of the X-ray spectra. The life history of the p-bar-p atom is considered in some detail, from the initial capture of the antiproton when stopping in hydrogen, through the atomic cascade with the emission of X-rays, to the final antiproton annihilation and production of mesons. The experiments carried out at LEAR are described and the results compared with atomic cascade calculations and predictions of strong interaction effects. (author)

  17. Symposium on Highlights from 14 years of LEAR Physics : "Atomic Physics" by E. Uggerhoj

    CERN Multimedia

    1998-01-01

    Symposium on Highlights from 14 years Physics hold at CERN, commemorating the closure of LEAR and giving a topical review of the impact of experiments with low energy antiprotons in their respective fields

  18. Symposium on Highlights from 14 years of LEAR Physics : "CP Violation" by P. Pavlopoulos

    CERN Multimedia

    1998-01-01

    Symposium on Highlights from 14 years Physics hold at CERN, commemorating the closure of LEAR and giving a topical review of the impact of experiments with low energy antiprotons in their respective fields

  19. FNAL main ring to energy save antiproton transfer system for Tevatron I

    International Nuclear Information System (INIS)

    A system for antiproton beam transfer from the Main Ring to the Energy Saver for colliding beam operations has been designed and fabricated. The system is similar to the existing proton beam transfer system used for fixed target operation of the Energy Saver. Using a fast kicker in the Main Ring, one or several bunches of 150 GeV pbars will be kicked horizontally across the septa of two Lambertsons into a short transfer line. At the end of this line, they are injected into the Energy Saver through two more Lambertsons and kicked onto a closed orbit by a second fast kicker. For commissioning and tune-up, the system will be operated in reverse, extracting 150 GeV protons from the Energy Saver to the Main Ring. In addition to a description of the design of the system and its components, the status of the installation and commissioning will also be discussed

  20. Nuclear Excitations by Antiprotons and Antiprotonic Atoms

    CERN Multimedia

    2002-01-01

    The proposal aims at the investigation of nuclear excitations following the absorption and annihilation of stopped antiprotons in heavier nuclei and at the same time at the study of the properties of antiprotonic atoms. The experimental arrangement will consist of a scintillation counter telescope for the low momentum antiproton beam from LEAR, a beam degrader, a pion multiplicity counter, a monoisotopic target and Ge detectors for radiation and charged particles. The data are stored by an on-line computer.\\\\ \\\\ The Ge detectors register antiprotonic x-rays and nuclear @g-rays which are used to identify the residual nucleus and its excitation and spin state. Coincidences between the two detectors will indicate from which quantum state the antiprotons are absorbed and to which nuclear states the various reactions are leading. The measured pion multiplicity characterizes the annihilation process. Ge&hyphn. and Si-telescopes identify charged particles and determine their energies.\\\\ \\\\ The experiment will gi...

  1. Antiproton-proton Annihilation Into Two Mesons: The Role Of Relativistic Distortion

    CERN Document Server

    El-Bennich, B O

    2004-01-01

    The more than a decade old data on differential cross sections and analyzing powers in antiproton-proton annihilation into two pions (or two kaons), measured at the Low Energy Antiproton Ring (LEAR) of CERN, have stimulated several theoretical investigations. A characteristic feature of the data are the large variations of the scattering observables as a function of the scattering angle and of the laboratory energy already below 100 MeV. Amplitude analyzes reproduce the data with few partial waves (J ≤ 4) and one concludes that the annihilation process is very short- ranged and of the order of the nucleon size. Nonetheless, early models, using either baryonic or quark degrees of freedom, give rise to an even shorter antibaryon-baryon interaction failing to produce substantial higher (J ≥ 2) partial wave amplitudes and consequently to adequately describe the LEAR data. In this thesis, we systematically consider improvements within the framework of quark-line diagrams. We first derive various quar...

  2. Measurement of small-angle antiproton-proton and proton-proton elastic scattering at the CERN intersecting storage rings

    NARCIS (Netherlands)

    Amos, N.; Block, M.M.; Bobbink, G.J.; Botje, M.A.J.; Favart, D.; Leroy, C.; Linde, F.; Lipnik, P.; Matheys, J-P.; Miller, D.

    1985-01-01

    Antiproton-proton and proton-proton small-angle elastic scattering was measured for centre-of-mass energies at the CERN Intersectung Storage Rings. In addition, proton-proton elastic scattering was measured at . Using the optical theorem, total cross sections are obtained with an accuracy of about

  3. Lear CAN analyzer

    OpenAIRE

    Peiró Ibañez, Felipe

    2013-01-01

    Since it was introduced in the automotive industry, the protocol CAN (Controller Area Network) has been widely used for its benefits. This has led many companies to offer several hardware and software solutions in order to monitor the communications that gives this protocol. The current master thesis presents the Lear CAN Analyzer as a software tool developed within the company LEAR Corporation. It is designed to be used in the automobile industry as a complement or substitute for other co...

  4. The measurement of antiproton-proton total cross sections and small-angle elastic scattering at low momentum

    International Nuclear Information System (INIS)

    In this thesis two low-momentum antiproton-proton (anti pp) experiments are described. The first one is a set of 24 high statistics anti pp total cross section measurements as a function of the incoming antiproton momentum between p=388 MeV/c and p=599 MeV/c. These measurements simultaneously yield the charge exchange cross section (anti pp → anti nn). The second one comprises two high statistics anti pp small-angle elastic scattering measurements at p=233 MeV/c and p=272 MeV/c. The measurements were carried out using the high quality antiproton beam extracted from the Low Energy Antiproton Ring (LEAR) at CERN. The physics motivation for these experiments is a search for anti pp resonances or bound states on one hand, and a detailed study of the anti pp interaction on the other hand. (orig.)

  5. Parallel plate chambers for monitoring the profiles of high-intensity pulsed antiproton beams

    CERN Document Server

    Hori, Masaki

    2004-01-01

    Two types of beam profile monitor with thin parallel-plate electrodes have been used in experiments carried out at the Low Energy Antiproton Ring (LEAR) and Antiproton Decelerator (AD) of CERN. The detectors were used to measure non-destructively the spatial profiles, absolute intensities, and time structures of 100-300-ns- long beam pulses containing between 10**7 and 10**9 antiprotons. The first of these monitors was a parallel plate ionization chamber operated at gas pressure P=65 mbar. The other was a secondary electron emission detector, and was operated in the ultra-high vacuum of the AD. Both designs may be useful in medical and commercial applications. The position-sensitive electrodes in these detectors were manufactured by a novel method in which a laser trimmer was used to cut strip patterns on metallized polyester foils.

  6. Polarization of antiprotons by antiproton decay

    International Nuclear Information System (INIS)

    The production of polarized antiproton beams at Fermilab is briefly reviewed. Two types of high-energy anti p polarimeters are described - the Coulomb-nuclear polarimeter and the Primakoff-effect polarimeter. The production of 8.9 GeV/c polarized antiprotons before entering the Fermilab accumulator ring is then discussed. 5 refs., 6 figs

  7. The CERN antiproton collector

    International Nuclear Information System (INIS)

    The Antiproton Collector is a new ring of much larger acceptance than the present accumulator. It is designed to receive 108 antiprotons per PS cycle. In order to be compatible with the Antiproton Accumulator, the momentum spread and the emittances are reduced from 6% to 0.2% and from 200 π mm mrad to 25 π mm mrad respectively. In addition to the ring itself, the new target area and the modifications to the stochastic systems of the Antiproton Accumulator are described. (orig.)

  8. Antiprotons are another matter

    International Nuclear Information System (INIS)

    Theories of gravity abound, whereas experiments in gravity are few in number. An important experiment in gravity that has not been performed is the measurement of the gravitational acceleration of antimatter. Although there have been attempts to infer these properties from those of normal matter, none of these theoretical arguments are compelling. Modern theories of gravity that attempt to unify gravity with the other forces of nature predict that in principle antimatter can fall differently than normal matter in the Earth's field. Some of these supergravity theories predict that antimatter will fall faster, and that normal matter will fall with a small Baryon-number dependance in the earth's field. All of these predictions violate the Weak Equivalence Principle, a cornerstone of General Relativity, but are consistent with CPT conservation. In our approved experiment at LEAR (PS-200) we will test the Weak Equivalence Principle for antimatter by measuring the gravitational acceleration of the antiproton. Through a series of deceleration stages, antiprotons from LEAR will be lowered in energy to ∼4 Kelvin at which energy the gravitational effect will be measureable. The measurement will employ the time-of-flight technique wherein the antiprotons are released vertically in a drift tube. The spectrum of time-of-flight measurements can be used to extract the gravitational acceleration experienced by the particles. The system will be calibrated using H- ions which simulates the electromagnetic behavior of the antiproton, yet is a baryon to ∼0.1%. To extract the gravitational acceleration of the antiproton relative to the H- ion with a statistical precision of 1% will require the release of ∼106 to 107 particles

  9. Energy dependence of proton-proton and antiproton-proton scattering at the CERN intersecting storage rings

    International Nuclear Information System (INIS)

    This thesis describes measurements of proton-proton and proton-antiproton elastic scattering with the scattered particles emerging at small angles in the centre of mass (CM) system. These measurements have been performed at the CERN Intersecting Storage Rings (ISR). The direct comparison of pp and anti pp scattering in this energy range is of considerable interest. This is because measurements on pp scattering alone, have revealed that in the ISR energy range both elastic- and total pp cross-sections increase with increasing energy. It is the subject of this thesis to check the prediction that the proton-antiproton cross section will do the same. The present experiment measures the angular distribution of pp and anti pp elastic scattering at small angles (typically 1-10 mrad) and at different energies. From these measurements a comparison of the energy behaviour of the pp and anti pp forward nuclear scattering amplitudes is obtained. This behaviour can be described in terms of three parameters: the total cross-section, the ratio of the real-to-imaginary part of the forward nuclear amplitude and a parameter, the slope, characterising the dependence of the process on the squared four-momentum transfer between the incident and the scattered particle. (Auth.)

  10. Coil for LEAR extraction septum

    CERN Multimedia

    1982-01-01

    Which way does the current flow ? This intriguing object is the coil for the LEAR extraction septum. There were two septa, first a thin one, then this one, not so thin, somewhat on the borderline between septum and bending magnet.

  11. Ring imaging Cherenkov counter of HERMES for pion, kaon, proton and anti-proton identification

    Energy Technology Data Exchange (ETDEWEB)

    Shibata, Toshi-Aki

    2014-12-01

    RICH of HERMES was built for identification of pion, kaon, proton and anti-proton in the momentum range of 2–15 GeV/c. It was a dual-radiator RICH. The radiators were aerogel and C{sub 4}F{sub 10} gas. Produced hadrons in electron–nucleon deep inelastic scattering were identified by the RICH and spin structure of the nucleon was studied by correlation between the directions of the target spin, scattered electron and produced hadrons.

  12. Precision measurement of antiprotonic hydrogen and deuterium X-rays

    Science.gov (United States)

    Heitlinger, K.; Bacher, R.; Badertscher, A.; Blüm, P.; Eades, J.; Egger, J.; Elsener, K.; Gotta, D.; Morenzoni, E.; Simons, L. M.

    1992-09-01

    X-rays from antiprotonic hydrogen and deuterium have been measured at low pressures. Using the cyclotron trap, a 105 MeV/c antiproton beam from LEAR was stopped with an efficiency of 86% in 30 mbar hydrogen gas in a volume of only 100 cm3. The X-rays were measured with Si(Li) detectors and a Xe-CH4 drift chamber. The strong interaction shift and broadening of the Lyman α transition and the spin-averaged 2p width in antiprotonic hydrogen was measured with unprecedented accuracy. The triplet component of the ground state in antiprotonic hydrogen was determined for the first time.

  13. Posing the first LEAR vacuum chamber

    CERN Multimedia

    1982-01-01

    The photo shows one of the four bending magnets of LEAR. They were of C-type with the opening ('mouth') to the outside of the ring (yoke to the inside). Last preparations are made before the vacuum chamber is slid through the mouth into the magnet. Stochastic cooling pickups/kickers were installed inside the chamber. One can distinguish a large number of feed-throughs on the chamber (leading to the pickup/kicker gaps). The free space in the middle of the block was left to offer room for an internal target in the magnet. This possibility was never exploited. Instead it is used here, to accommodate a pumping port for the high vacuum system. Michel Chanel (left) and Pierre Lefevre admire the mechanics at work.

  14. Lear and the learned Theban

    Directory of Open Access Journals (Sweden)

    David Ian Clive Lucking

    2014-07-01

    Full Text Available Abstract - The affinities between Shakespeare’s King Lear and Sophocles’ Oedipus the King, and in particular the pattern of allusion to eyes and to eyesight developed in both plays, is familiar critical terrain. The purpose of this essay is to consider in a somewhat broader perspective King Lear’s relation not only with Oedipus the King, but with the entire group of works generally referred to as the Theban plays. Elements in common between the works by Shakespeare and Sophocles, among which are the eyesight motif and its symbolic connotations, the figures of devoted daughters, a concern with relationships between parents and children, and an interest in what constitutes real knowledge of the self and of the world, are discussed in the first section of the essay. The question of why such parallels should exist, and in particular of whether Shakespeare knew Sophocles’ works either at first hand or as mediated through the derivative plays of Seneca, is investigated in the second part, while in the third the symbolic implications of the sight pattern shared by the works are examined in depth.Keywords: Shakespeare, Sophocles, King Lear, Theban plays, Oedipus.

  15. An Interview with Dr. Walter Lear

    Directory of Open Access Journals (Sweden)

    The Editors

    2009-03-01

    Full Text Available In this issue of the English version of Social Medicine we are publishing the first of several pamphlets loaned to us by the US Health Activism History Collection. To introduce this collection we travelled to Philadelphia on June 18, 2008 to interview Dr. Walter J. Lear. Dr Lear, born in 1923, is the person responsible for the collection. In a wide-ranging interview in his home Dr. Lear discussed his personal background, the origins and purpose of the collection, the impact of the McCarthy period on the US health left, as well as his vision for the future.

  16. Antiproton radiotherapy

    CERN Document Server

    Bassler, Niels; Beyer, Gerd; DeMarco, John J.; Doser, Michael; Hajdukovic, Dragan; Hartley, Oliver; Iwamoto, Keisuke S.; Jakel, Oliver; Knudsen, Helge V.; Kovacevic, Sandra; Møller, Søren Pape; Overgaard, Jens; Petersen, Jørgen B.à; Solberg, Timothy D.; Sørensen, Brita S.; Vranjes, Sanja; Wouters, Bradly G.; Holzscheiter, Michael H.

    2008-01-01

    Antiprotons are interesting as a possible future modality in radiation therapy for the following reasons: When fast antiprotons penetrate matter, protons and antiprotons have near identical stopping powers and exhibit equal radiobiology well before the Bragg-peak. But when the antiprotons come to rest at the Bragg-peak, they annihilate, releasing almost 2 GeV per antiproton–proton annihilation. Most of this energy is carried away by energetic pions, but the Bragg-peak of the antiprotons is still locally augmented with ∼20–30 MeV per antiproton. Apart from the gain in physical dose, an increased relative biological effect also has been observed, which can be explained by the fact that some of the secondary particles from the antiproton annihilation exhibit high-LET properties. Finally, the weakly interacting energetic pions, which are leaving the target volume, may provide a real time feedback on the exact location of the annihilation peak. We have performed dosimetry experiments and investigated the rad...

  17. Ultra-low Energy Antiprotons at FLAIR

    OpenAIRE

    Welsch, C.; Grieser, M.; von Hahn, R; Orlov, D.; Wolf, A.; Ullrich, J.

    2004-01-01

    The Future Accelerator Facility for Beams of Ions and Antiprotons at Darmstadt will produce the highest flux of antiprotons in the world. So far it is foreseen to accelerate the antiprotons to high energies (3-15 GeV) for meson spectroscopy and other nuclear and particle physics experiments in the HESR (High Energy Storage Ring). Within the planned complex of storage rings, it is possible to decelerate the antiprotons to about 30 MeV kinetic energy, opening up the possibility to create low en...

  18. Antiproton production

    International Nuclear Information System (INIS)

    The results for the antiproton momentum spectrum produced in proton reactions on lead at the CERN Antiproton Accumulator is scaled to AGS operating conditions using the Sanford-Wang formula with no correction for target material. Yield predictions as a function of momentum are shown for 28.3 GeV protons on beryllium and results are converted to antiproton beam flux. The AGS Medium Energy Separated Beam has a flux which is a factor of 2 lower than Sanford-Wang predictions. This may be due to factors affecting beam acceptance

  19. Extra Low ENergy Antiproton

    CERN Multimedia

    To produce dense antiproton beams at very low energies (110 keV), it has been proposed to install a small decelerator ring between the existing AD ring and the experimental area. Phase-space blowup during deceleration is compensated by electron cooling such that the final emittances are comparable to the 5MeV beam presently delivered by the AD. An immediate consequence is a significant increase in the number of trapped antiprotons at the experiments as outlined in the proposal CERN/SPSC-2009-026; SPCS-P-338. This report describes the machine parameters and layout of the proposal ELENA (Extra Low ENergy Antiproton)ring also gives an approximate estimate of cost and manpower needs. Since the initial estimate, published in 2007 (CERN-AB-2007-079), the ELENA design has evolved considerably. This is due to a new location in the AD hall to acommodate for the possibility of another experimental zone, as suggested by the SPCS, and also due to improvements in the ring optics and layout. The cost estimate that is prese...

  20. Antiprotonic helium

    CERN Multimedia

    Eades, John

    2005-01-01

    An exotic atom in w hich an electron and an antiproton orbit a helium nucleus could reveal if there are any differences between matter and antimatter. The author describes this unusual mirror on the antiworld (5 pages)

  1. Radiation studies in the antiproton source

    International Nuclear Information System (INIS)

    Experiment E760 has a lead glass (Pb-G) calorimeter situated in the antiproton source tunnel in the accumulator ring at location A50. This location is exposed to radiation from several sources during antiproton stacking operations. A series of radiation studies has been performed over the last two years to determine the sources of this radiation and as a result, some shielding has been installed in the antiproton source in order to protect the lead glass from radiation damage

  2. Precision measurement of antiprotonic hydrogen and deuterium X-rays

    Energy Technology Data Exchange (ETDEWEB)

    Heitlinger, K.; Bluem, P. (Kernforschungszentrum Karlsruhe GmbH (Germany). Inst. fuer Kernphysik Karlsruhe Univ. (T.H.) (Germany). Inst. fuer Experimentelle Kernphysik); Bacher, R.; Badertscher, A.; Egger, J.; Morenzoni, E.; Simons, L.M. (Paul Scherrer Inst. (PSI), Villigen (Switzerland)); Eades, J.; Elsener, K. (European Organization for Nuclear Research, Geneva (Switzerland)); Gotta, D. (Forschungszentrum Juelich GmbH (Germany). Inst. fuer Kernphysik)

    1992-05-01

    X-rays from antiprotonic hydrogen and deuterium have been measured at low pressures. Using the cylcotron trap, a 105 MeV/c antiproton beam from LEAR was stopped with an efficiency of 86% in 30 mbar hydrogen gas in a volume of only 100 cm{sup 3}. The X-rays were measured with Si(Li) detectors and a Xe-CH{sub 4} drift chamber. The strong interaction shift and broadening of the Lyman {alpha} transition and the spin-averaged 2p width in antiprotonic hydrogen was measured with unprecedented accuracy. The triplet component of the ground state in antiprotonic hydrogen was determined for the first time. (orig.).

  3. Capture, Electron-Cooling and Compression of Antiprotons in a Large Penning-Trap for Physics Experiments with an Ultra-Low Energy Extracted Antiproton Beam

    CERN Multimedia

    2002-01-01

    % PS200 \\\\ \\\\The availability of ultra-low energy antiprotons is a crucial ingredient for the execution of the gravity measurements PS200. We have developed a method to provide such low energy antiprotons based on a large Penning trap (the PS200 catching trap). This system can accept a fast-extracted pulse from LEAR, reduce the energy of the antiprotons in the pulse from 5.9~MeV to several tens of kilovolts using a degrading foil, and then capture the antiprotons in a large Penning trap. These antiprotons are cooled by electrons previously admitted to the trap and are collected in a small region at the center of the trap. We have demonstrated our capability to capture up to 1~million antiprotons from LEAR in a single shot, electron cool these antiprotons, and transfer up to 95\\% of them into the inner, harmonic region. A storage time in excess of 1 hour was observed. These results have been obtained with the cryogenic trap vacuum coupled to a room temperature vacuum at about l0$ ^- ^{1} ^0 $ Torr, which is an...

  4. Antiproton Target

    CERN Multimedia

    1980-01-01

    Antiproton target used for the AA (antiproton accumulator). The first type of antiproton production target used from 1980 to 1982 comprised a rod of copper 3mm diameter and 120mm long embedded in a graphite cylinder that was itself pressed into a finned aluminium container. This assembly was air-cooled and it was used in conjunction with the Van der Meer magnetic horn. In 1983 Fermilab provided us with lithium lenses to replace the horn with a view to increasing the antiproton yield by about 30%. These lenses needed a much shorter target made of heavy metal - iridium was chosen for this purpose. The 50 mm iridium rod was housed in an extension to the original finned target container so that it could be brought very close to the entrance to the lithium lens. Picture 1 shows this target assembly and Picture 2 shows it mounted together with the lithium lens. These target containers had a short lifetime due to a combination of beam heating and radiation damage. This led to the design of the water-cooled target in...

  5. Antiproton Cancer Therapy

    DEFF Research Database (Denmark)

    Bassler, Niels

    Antiprotons are interesting as a modality in radiation therapy for the following reasons: When fast antiprotons penetrate matter, they behave as protons. Well before the Bragg-peak, protons and antiprotons have near identical stopping powers exhibit equal radiobiology. But when the antiprotons co...

  6. Antiproton--Proton Scattering Experiments with Polarization

    CERN Document Server

    Lenisa, P; Lenisa, Paolo; Rathmann, Frank

    2005-01-01

    The document describes the physics case of the PAX experiment using polarized antiprotons, which has recently been proposed for the new Facility for Antiprotons and Ions Research (FAIR) at GSI--Darmstadt. Polarized antiprotons provide access to a wealth of single-- and double--spin observables, thereby opening a new window to physics uniquely accessible at the HESR. The polarized antiprotons would be most efficiently produced by spin--filtering in a dedicated Antiproton Polarizer Ring (APR) using an internal polarized hydrogen gas target. In the proposed collider scenario of the PAX experiment, polarized protons stored in a COSY--like Cooler Storage Ring (CSR) up to momenta of 3.5 GeV/c are bombarded head--on with 15 GeV/c polarized antiprotons stored in the HESR. This asymmetric double--polarized antiproton--proton collider is ideally suited to map, e.g., the transversity distribution in the proton. The proposed detector consists of a large--angle apparatus optimized for the detection of Drell--Yan electron ...

  7. The anti-proton charge radius

    CERN Document Server

    Crivelli, P; Heiss, M W

    2016-01-01

    The upcoming operation of the Extra Low ENergy Antiprotons (ELENA) ring at CERN, the upgrade of the anti-proton decelerator (AD), and the installation in the AD hall of an intense slow positron beam with an expected flux of $10^{8}$ e$^+$/s will open the possibility for new experiments with anti-hydrogen ($\\bar{\\text{H}}$). Here we propose a scheme to measure the Lamb shift of $\\bar{\\text{H}}$. For a month of data taking, we anticipate an uncertainty of 100 ppm. This will provide a test of CPT and the first determination of the anti-proton charge radius at the level of 10%.

  8. Antiproton therapy

    CERN Document Server

    Knudsen, Helge V; Bassler, Niels; Alsner, Jan; Beyer, Gerd-Jürgen; DeMarco, John J; Doser, Michael; Hajdukovic, Dragan; Hartley, Oliver; Iwamoto, Keisuke S; Jäkel, Oliver; Kovacevic, Sandra; Møller, Søren Pape; Overgaard, Jens; Petersen, Jørgen B; Ratib, Osman; Solberg, Timothy D; Vranjes, Sanja; Wouters, Bradly G

    2008-01-01

    Radiotherapy is one of the most important means we have for the treatment of localised tumours. It is therefore essential to optimize the technique, and a lot of effort goes into this endeavour. Since the proposal by Wilson in 1946 [R.R. Wilson, Radiology use of fast protons, Radiology 47 (1946) 487.] that proton beams might be better than photon beams at inactivating cancer cells, hadron therapy has been developed in parallel with photon therapy and a substantial knowledge has been gained on the effects of pions, protons and heavy ions (mostly carbon ions). Here we discuss the recent measurements by the CERN ACE collaboration of the biological effects of antiprotons, and argue that these particles very likely are the optimal agents for radiotherapy.

  9. Blindness and Insight in King Lear

    Institute of Scientific and Technical Information of China (English)

    岳元玉

    2008-01-01

    This paper intends to explore how William Shakespeare illustrates the theme of blindness and insight in his great tragedy "King Lear".Four characters’ deeds and their fate are used as a case study to examine what blindness is,what insight is,and the relationship between the two.The writer finds that by depicting the characters’ deeds and their fate in a double plot,Shakespeare renders the folly of blindness,the transition from blindness to insight,and the use of reason and thought to understand the truth.

  10. The crystal barrel spectrometer at LEAR

    International Nuclear Information System (INIS)

    The Crystal Barrel spectrometer used at LEAR, CERN to study the products of anti pp and anti pd annihilations is described. A 1380 element array of CsI crystals measures photons from the decay of π0, η, η' and ω mesons. A segmented drift chamber in a 1.5 T magnetic field is used to identify and measure charged particles. A fast on-line trigger on charged and neutral multiplicities and on the invariant mass of secondary particles is available. The performance of the detector is discussed. (orig.)

  11. Atomic Spectroscopy and Collisions Using Slow Antiprotons \\\\ ASACUSA Collaboration

    CERN Multimedia

    Matsuda, Y; Lodi-rizzini, E; Kuroda, N; Schettino, G; Hori, M; Pirkl, W; Mascagna, V; Malbrunot, C L S; Yamazaki, Y; Eades, J; Simon, M; Massiczek, O; Sauerzopf, C; Breuker, H; Nagata, Y; Uggerhoj, U I; Mc cullough, R W; Toekesi, K M; Venturelli, L; Widmann, E; Zmeskal, J; Kanai, Y; Hayano, R; Knudsen, H; Kristiansen, H; Todoroki, K; Bartel, M A; Moller, S P; Charlton, M; Leali, M; Diermaier, M; Kolbinger, B

    2002-01-01

    ASACUSA (\\underline{A}tomic \\underline{S}pectroscopy \\underline{A}nd \\underline{C}ollisions \\underline{U}sing \\underline{S}low \\underline{A}ntiprotons) is a collaboration between a number of Japanese and European research institutions, with the goal of studying bound and continuum states of antiprotons with simple atoms.\\\\ Three phases of experimentation are planned for ASACUSA. In the first phase, we use the direct $\\overline{p}$ beam from AD at 5.3 MeV and concentrate on the laser and microwave spectroscopy of the metastable antiprotonic helium atom, $\\overline{p}$He$^+$, consisting of an electron and antiproton bound by the Coulomb force to the helium nucleus. Samples of these are readily created by bringing AD antiproton beam bunches to rest in helium gas. With the help of techniques developed at LEAR for resonating high precision laser beams with antiproton transitions in these atoms, ASACUSA achieved several of these first-phase objectives during a few short months of AD operation in 2000. Six atomic tr...

  12. Measurement of Balmer and Lyman X-rays in antiprotonic hydrogen isotopes at pressures below 300 hPa

    Energy Technology Data Exchange (ETDEWEB)

    Bacher, R.; Bluem, P.; Gotta, D.; Heitlinger, K.; Rohmann, D.; Schneider, M.; Egger, J.; Simons, L.M.; Elsener, K.

    1989-09-01

    X-rays of Balmer and Lyman transitions in antiprotonic hydrogen and of Balmer transitions in antiprotonic deuterium were observed at pressures below 300 hPa using Si(Li) semiconductor detectors. The measurement was performed at the LEAR-facility at a beam momentum of 202 MeV/c. In order to stop antiprotons in a low pressure gaseous target with high efficiency, a novel technique, the cyclotron trap has been used. Absolute yields were determined and compared with cascade calculations. A distinct difference in the cascade of antiprotonic hydrogen and deuterium is found. The parameters of strong interaction in antiprotonic hydrogen are determined to be /epsilon//sub 1s/=-(620+-100) eV, /Gamma//sub 1s/=(1130+-170) eV and /Gamma//sub 2p/=(32+-10) meV. (orig.).

  13. Antiproton Radiation Therapy

    DEFF Research Database (Denmark)

    Bassler, Niels; Holzscheiter, Michael H.; Petersen, Jørgen B.B.

    2007-01-01

    The AD-4/ACE collaboration at CERN is investigating the anticipated benefit of antiproton radiotherapy. The experimental tasks have been twofold: 1) To quantify the radiobiological properties of the antiproton beam. 2) Perform absolute dosimetry on a pulsed antiproton beam. In order to do define ...

  14. Antiprotons get biological

    CERN Multimedia

    2003-01-01

    After its final run in September, the first results of the Antiproton Cell Experiment (ACE) look very promising. It was the first experiment to take data on the biological effects of antiproton beams to evaluate the potential of antiprotons in radiation therapy.

  15. X-rays from antiprotonic3He and4He

    Science.gov (United States)

    Schneider, M.; Bacher, R.; Blüm, P.; Gotta, D.; Heitlinger, K.; Kunold, W.; Rohmann, D.; Egger, J.; Simons, L. M.; Elsener, K.

    1991-06-01

    Antiprotonic X-rays from the helium isotopes have been observed at pressures of 36, 72, 375 and 600 mbar. The antiproton beam from LEAR with momenta of 309 and 202 MeV/c has been stopped at these pressures using the cyclotron trap. The X-rays were detected with Si (Li) and intrinsic Ge semiconductor detectors. Absolute X-ray yields were determined and the strong-interaction 2p shifts and the 2p and 3d broadenings measured to be ɛ2p=(-17±4) eV, Γ2p=(25±9) eV and Γ3d=(2.14 ±0.18) meV for ¯p3He and ɛ2p=(-18±2) eV, Γ2p =(45±5) eV and Γ3d=(2.36±0.10) meV for ¯p4He.

  16. View of the CERN Antiproton Decelerator (AD) and portrait of Prof. Tommy Eriksson, in charge of the AD machine.

    CERN Multimedia

    Maximilien Brice

    2011-01-01

    The Antiproton Decelerator (AD) is a storage ring at the CERN laboratory in Geneva. It started operation in 2000. It decelerates antiprotons before sending them to several experiments studying antimatter : ALPHA, ASACUSA, ATRAP and ACE.

  17. Antiproton Focus Horn

    CERN Multimedia

    1974-01-01

    Was used for the AA (antiproton accumulator). Making an antiproton beam took a lot of time and effort. Firstly, protons were accelerated to an energy of 26 GeV in the PS and ejected onto a metal target. From the spray of emerging particles, a magnetic horn picked out 3.6 GeV antiprotons for injection into the AA through a wide-aperture focusing quadrupole magnet.For a million protons hitting the target, just one antiproton was captured, 'cooled' and accumulated. It took 3 days to make a beam of 3 x 10^11 -, three hundred thousand million - antiprotons.

  18. AMS-02 Antiprotons Reloaded

    CERN Document Server

    Kappl, Rolf; Winkler, Martin Wolfgang

    2015-01-01

    The AMS-02 collaboration has released preliminary data on the antiproton fraction in cosmic rays. The surprisingly hard antiproton spectrum at high rigidity has triggered speculations about a possible primary antiproton component originating from dark matter annihilations. In this note, we employ newly available AMS-02 boron to carbon data to update the secondary antiproton flux within the standard two-zone diffusion model. The new background permits a considerably better fit to the measured antiproton fraction compared to previous estimates. This is mainly a consequence of the smaller slope of the diffusion coefficient favored by the new AMS-02 boron to carbon data.

  19. Beam position pickup for antiprotons to the ISR

    CERN Multimedia

    CERN PhotoLab

    1981-01-01

    The Antiproton Project, launched for proton-antiproton collisions in the SPS (SPS collider), had a side-line for p-pbar collisions in the ISR. A new transfer line, TT6, was constructed to transport antiprotons from the 26 GeV PS to the injection line TT1 of ISR ring 2. Antiprotons were a scarce commodity. For setting up the lines, beam diagnostic devices in the antiproton path had to work reliably and precisely with just a few low-intensity pilot pules: single bunches of about 2x10**9 antiprotons every few hours. Electrostatic pickup electrodes were used to measure beam position. They could be mounted for measurement in the horizontal plane, as in this picture, or at 90 deg, for the vertical plane.

  20. Laser Spectroscopy of Antiprotonic Helium Atoms

    CERN Multimedia

    2002-01-01

    %PS205 %title\\\\ \\\\Following the discovery of metastable antiprotonic helium atoms ($\\overline{p}He^{+} $) at KEK in 1991, systematic studies of their properties were made at LEAR from 1991 to 1996. In the first two years the lifetime of $\\overline{p}He^{+}$ in liquid and gaseous helium at various temperatures and pressures was measured and the effect of foreign gases on the lifetime of these atoms was investigated. Effects were also discovered which gave the antiproton a 14\\% longer lifetime in $^4$He than in $^3$He, and resulted in important differences in the shape of the annihilation time spectra in the two isotopes.\\\\ \\\\Since 1993 laser spectroscopy of the metastable $\\overline{p}He^{+}$ atoms became the main focus of PS205. Transitions were stimulated between metastable and non-metastable states of the $\\overline{p}He^{+}$ atom by firing a pulsed dye laser beam into the helium target every time an identified metastable atom was present (Figure 1). If the laser frequency matched the transition energy, the...

  1. Towards an antiproton measurement with AMS-02

    Energy Technology Data Exchange (ETDEWEB)

    Bachlechner, Andreas [RWTH Aachen University (Germany)

    2015-07-01

    AMS-02 is a multi-purpose high-precision particle detector. It has been onboard the International Space Station since May 2011. The antiprotons measurement is an important part of the AMS-02 physics program. An excess above the expected spectrum due to interactions of cosmic rays with the interstellar matter can hint at exotic sources like dark matter annihilation. The antiproton-to-proton ratio and the antiproton flux itself may also improve the understanding of the origin and propagation of cosmic rays. Due to the very small fraction of antiprotons in the cosmic radiation of about 10{sup -5} compared to protons a very precise particle identification is needed. The main backgrounds are other singly charged particles like protons, electrons, and pions produced within the detector material itself. At lower energies the ring-imaging Cherenkov detector and the time-of-flight system help to separate light particles from protons. The electromagnetic calorimeter and the transition radiation detector redundantly suppress the electron background. The reconstruction of the charge sign by the magnetic spectrometer is limited by its resolution and has to be taken into account carefully. The strategies to identify antiprotons in the cosmic-ray measurement in different energy regions are presented. Methods to suppress and the effect of the backgrounds to the antiproton-to-proton ratio are discussed.

  2. Recent Results on Lead-Ion Accumulation in LEAR for the LHC

    CERN Document Server

    Baird, S A; Broere, J; Carli, Christian; Chanel, M; Hill, C; Ley, R; Lombardi, A M; MacCaferri, R; Maury, S; Möhl, D; Molinari, G; Mulder, H; Tanke, E; Tranquille, G; Varenne, F; Vretenar, Maurizio; Meshkov, I N; Syresin, E M

    1997-01-01

    To prepare dense bunches of lead ions for the LHC it has been proposed to accumulate the 4.2 MeV/u linac beam in a storage ring with electron cooling. A series of experiments is being performed in the low-energy ring LEAR to test this technique. First results were already reported at the Beam Crystallisation Workshop in Erice in November 1995. Two more recent runs to complement these investigations were concerned with: further study of the beam lifetime; the dependence of the cooling time on optical settings of the storage ring and on neutralization of the electron beam; tests in view of multiturn injection. New results obtained in these two runs in December 1995 and in April 1996 will be discussed in this contribution.

  3. ASACUSA hits antiproton jackpot

    CERN Multimedia

    2001-01-01

    The Japanese-European ASACUSA collaboration, which takes its name from the oldest district of Tokyo, approaches the antimatter enigma in a different way from the other two AD experiments, by inserting antiprotons into ordinary atoms. Last month the collaboration succeeded in trapping about a million antiprotons. The ASACUSA antiproton trap (lower cylinder), surmounted by its liquid helium reservoir. Looking on are Ken Yoshiki-Franzen, Zhigang Wang, Takahito Tasaki, Suzanne Reed, John Eades, Masaki Hori, Yasunori Yamazaki, Naofumi Kuroda, Jun Sakaguchi, Berti Juhasz, Eberhard Widmann and Ryu Hayano. A key element of the ASACUSA apparatus is its decelerating Radiofrequency Quadrupole magnet, RFQD. After tests with protons in Aarhus, this was installed in ASACUSA's antiproton beam last October (Bulletin 41/2000, 9 October 2000). Constructed by Werner Pirkl's group in PS Division, the RFQD works by applying an electric field to the AD antiproton pulse the opposite direction to its motion. As the antiprotons slo...

  4. Antiprotonic Helium Atoms

    OpenAIRE

    Kartavtsev, O. I.

    1995-01-01

    Metastable antiprotonic helium atoms $^{3,4}\\! H\\! e\\bar pe$ have been discovered recently in experiments of the delayed annihilation of antiprotons in helium media. These exotic atoms survive for an enormous time (about tens of microseconds) and carry the extremely large total angular momentum $L\\sim 30-40$. The theoretical treatment of the intrinsic properties of antiprotonic helium atoms, their formation and collisions with atoms and molecules is discussed.

  5. Physics with Antiprotons at PANDA

    International Nuclear Information System (INIS)

    The PANDA experiment is part of the core project of the planned Facility for Antiproton and Ion Research (FAIR) at GSI in Darmstadt (Germany)[1]. One major component of the upgraded accelerator complex is the High Energy Storage Ring (HESR) which will provide a high quality antiproton beam in the momentum range between 1.5 and 15 GeV/c. PANDA, a fixed target experiment directly implemented in the HESR, will investigate antiproton annihilations with the aim to explore fundamental questions in the cross over region of the non perturbative and the strong QCD. Due to the planned extensive physics program a multipurpose detector with a nearly complete solid angle coverage, proper particle identification over a large momentum range, and high resolution calorimetry for neutral particles is required. After an overview about the goals and the detector design of the PANDA experiment major parts of the planned physics program will be discussed, namely the meson spectroscopy and the search for exotics in the charmonium and open charm region

  6. Improvements to Antiproton Accumulator to Recycler Transfers at the Fermilab Tevatron Collider

    Energy Technology Data Exchange (ETDEWEB)

    Morgan, J.P.; Drendel, B.; Vander Muelen, D.; /Fermilab

    2009-04-01

    Since 2005, the Recycler has become the sole storage ring for antiprotons used in the Tevatron Collider. The operational role of the Antiproton Source has shifted to exclusively producing antiprotons for periodic transfers to the Recycler. The process of transferring the antiprotons from the Accumulator to the Recycler has been greatly improved, leading to a dramatic reduction in the transfer time. The reduction in time has been accomplished with both an improvement in transfer efficiency and an increase in average stacking rate. This paper will describe the improvements that have streamlined the transfer process and other changes that contributed to a significant increase in the number of antiprotons available to the Collider.

  7. Review the Nature and the Humanity in King Lear

    Institute of Scientific and Technical Information of China (English)

    CHEN Zhi-lan

    2015-01-01

    Tragedy is the art that purifies the mind. Through richly-drawn impressive characters, King Lear illustrates the same⁃ness of human nature and manifest the common outlook on humanity in Chinese and western culture. King Lear should be studied from the perspectives of dialectics of nature and history of social development.Through manifestation of nature and human beings, King Lear proves to be deeply touching for being earthshaking, society-changing and mind-purifying.The artistic value of this trag⁃edy lies in that the truth, the good and the beauty against the fake,the bad and the ugly. All these contributes to its extraordinary standing in aesthetics, philosophy, anthropology, sociology and psychology.

  8. Antiprotons at Solar Maximum

    CERN Document Server

    Bieber, J W; Engel, R; Gaisser, T K; Roesler, S; Stanev, T; Bieber, John W.; Engel, Ralph; Gaisser, Thomas K.; Roesler, Stefan; Stanev, Todor

    1999-01-01

    New measurements with good statistics will make it possible to observe the time variation of cosmic antiprotons at 1 AU through the approaching peak of solar activity. We report a new computation of the interstellar antiproton spectrum expected from collisions between cosmic protons and the interstellar gas. This spectrum is then used as input to a steady-state drift model of solar modulation, in order to provide predictions for the antiproton spectrum as well as the antiproton/proton ratio at 1 AU. Our model predicts a surprisingly large, rapid increase in the antiproton/proton ratio through the next solar maximum, followed by a large excursion in the ratio during the following decade.

  9. Progress in Antiproton Production at the Fermilab Tevatron Collider

    Energy Technology Data Exchange (ETDEWEB)

    Pasquinelli, Ralph J.; Drendel, Brian; Gollwitzer, Keith; Johnson, Stan; Lebedev, Valeri; Leveling, Anthony; Morgan, James; Nagaslaev, Vladimir; Peterson, Dave; Sondgeroth, Alan; Werkema, Steve; /Fermilab

    2009-04-01

    Fermilab Collider Run II has been ongoing since 2001. During this time peak luminosities in the Tevatron have increased from approximately 10 x 10{sup 30} cm{sup -2}sec{sup -1} to 300 x 10{sup 30} cm{sup 02}sec{sup -1}. A major contributing factor in this remarkable performance is a greatly improved antiproton production capability. Since the beginning of Run II, the average antiproton accumulation rate has increased from 2 x 10{sup 10}{anti p}/hr to about 24 x 10{sup 10}{anti p}/hr. Peak antiproton stacking rates presently exceed 28 x 10{sup 10}{anti p}/hr. The antiproton stacking rate has nearly doubled since 2005. It is this recent progress that is the focus of this paper. The process of transferring antiprotons to the Recycler Ring for subsequent transfer to the collider has been significantly restructured and streamlined, yielding additional cycle time for antiproton production. Improvements to the target station have greatly increased the antiproton yield from the production target. The performance of the Antiproton Source stochastic cooling systems has been enhanced by upgrades to the cooling electronics, accelerator lattice optimization, and improved operating procedures. In this paper, we will briefly report on each of these modifications.

  10. Shame, recognition and love in Shakespeare’s 'King Lear'

    DEFF Research Database (Denmark)

    Montes Sanchez, Alba

    2014-01-01

    In this paper, I explore the experience of shame and its connections to recognition and love as manifested in Shakespeare’s King Lear. My main focus in this paper is the ethical relevance of shame. I start from Sartre’s account of shame in Being and Nothingness, and I consider Webber’s attempt to...

  11. Elastic and inelastic scattering of antiprotons

    International Nuclear Information System (INIS)

    During the last two years very interesting results have been collected at LEAR on both the elementary pantip and the antip nucleus interactions. A review of all the interesting experimental results already available is far beyond the scope of the present talk. Its topic will be essentially limited to report on the new experimental informations dealing with the knowledge of the fundamental properties of the antip p elementary interaction and the determination of the characteristics of the antip nucleus interaction. The results of the antip p cross sections measured at low momenta by the PS173 and PS172 experiments are discussed. The antip nucleus elastic scattering angular distributions collected by the PS184 experiment have significantly contributed to define the properties of the p nucleus optical potential and stimulated a lot of microscopic calculations. The results are reviewed. A comparison to the informations obtained from the measurements of X-rays in antiprotonic atoms done by the PS176 and PS186 experiments is given. The interpretation of the inelastic scattering data measured for the 12C(antip, antip)12C* system at 47 and 180 MeV for various discrete states is presented: special emphasis will be given to the study of spin-flip transitions to unnatural parity states which would provide significant constant on the isovector tensor component of the NantiN interaction. Status on the experimental study of the (antip, p) reaction is discussed

  12. Structural Integrity Evaluation of the Lear Fan 2100 Aircraft

    Science.gov (United States)

    Kan, H. P.; Dyer, T. A.

    1996-01-01

    An in-situ nondestructive inspection was conducted to detect manufacturing and assembly induced defects in the upper two wing surfaces (skin s) and upper fuselage skin of the Lear Fan 2100 aircraft E009. The effects of the defects, detected during the inspection, on the integrity of the structure was analytically evaluated. A systematic evaluation was also conducted to determine the damage tolerance capability of the upper wing skin against impact threats and assembly induced damage. The upper wing skin was divided into small regions for damage tolerance evaluations. Structural reliability, margin of safety, allowable strains, and allowable damage size were computed. The results indicated that the impact damage threat imposed on composite military aircraft structures is too severe for the Lear Fan 2100 upper wing skin. However, the structural integrity is not significantly degraded by the assembly induced damage for properly assembled structures, such as the E009 aircraft.

  13. A arara-azul-de-Lear, Anodorhynchus leari Bonaparte, 1856

    OpenAIRE

    Helmut Sick; Luiz Pedreira Gonzaga; Dante Martins Teixeira

    1986-01-01

    The case of the Indigo, or Lear's Macaw, Anodorhynchus leari, is unique in South American ornithology. The species, although described more than 100 years ago, was known only through very few living specimens, which entered occasionally the bird trade, without any indication of their origins. It was presumed "probably some part of Brazil" (Salvadori, 1891). The last speculation was that it was unlikely, though not impossible, that the Indigo Macaw might not be an independem species, but rathe...

  14. Short quadrupole, first at the SC, then at LEAR

    CERN Multimedia

    1982-01-01

    Quadrupoles of this type were built for the beam lines of the 600 MeV Synchro-Cylclotron. Surplus ones were installed in the LEAR injection line. The particularity of these quads is that they are very short and that a special design, resembling the "Lambertson magnet", limits and linearizes their stray field. This was achieved by the iron between the poles extending beyond the poles.

  15. Biological Effectiveness of Antiproton Annihilation

    DEFF Research Database (Denmark)

    Maggiore, C.; Agazaryan, N.; Bassler, N.;

    2004-01-01

    from the annihilation of antiprotons produce an increase in ‘‘biological dose’’ in the vicinity of the narrow Bragg peak for antiprotons compared to protons. This experiment is the first direct measurement of the biological effects of antiproton annihilation. The background, description, and status...

  16. Biological effectiveness of antiproton annihilation

    CERN Document Server

    Holzscheiter, Michael H.; Bassler, Niels; Beyer, Gerd; De Marco, John J.; Doser, Michael; Ichioka, Toshiyasu; Iwamoto, Keisuke S.; Knudsen, Helge V.; Landua, Rolf; Maggiore, Carl; McBride, William H.; Møller, Søren Pape; Petersen, Jorgen; Smathers, James B.; Skarsgard, Lloyd D.; Solberg, Timothy D.; Uggerhøj, Ulrik I.; Withers, H.Rodney; Vranjes, Sanja; Wong, Michelle; Wouters, Bradly G.

    2004-01-01

    We describe an experiment designed to determine whether or not the densely ionizing particles emanating from the annihilation of antiprotons produce an increase in “biological dose” in the vicinity of the narrow Bragg peak for antiprotons compared to protons. This experiment is the first direct measurement of the biological effects of antiproton annihilation. The experiment has been approved by the CERN Research Board for running at the CERN Antiproton Decelerator (AD) as AD-4/ACE (Antiproton Cell Experiment) and has begun data taking in June of 2003. The background, description and the current status of the experiment are given.

  17. Biological effectiveness of antiproton annihilation

    DEFF Research Database (Denmark)

    Holzscheiter, M.H.; Agazaryan, N.; Bassler, Niels;

    2004-01-01

    We describe an experiment designed to determine whether or not the densely ionizing particles emanating from the annihilation of antiprotons produce an increase in ‘‘biological dose’’ in the vicinity of the narrow Bragg peak for antiprotons compared to protons. This experiment is the first direct...... measurement of the biological effects of antiproton annihilation. The experiment has been approved by the CERN Research Board for running at the CERN Antiproton Decelerator (AD) as AD-4/ACE (Antiproton Cell Experiment) and has begun data taking in June of 2003. The background, description and the current...

  18. Coincidence studies with antiprotons

    Energy Technology Data Exchange (ETDEWEB)

    McGovern, M; Walters, H R J [Department of Applied Mathematics and Theoretical Physics, Queen' s University, Belfast BT7 1NN (United Kingdom); Assafrao, D; Mohallem, J R [Laboratorio de Atomos e Moleculas Especiais, Departamento de Fisica, ICEx, Universidade Federal de Minas Gerais, P.O Box 702, 30123-970 Belo Horizonte, MG (Brazil); Whelan, Colm T, E-mail: mmcgovern06@qub.ac.u [Department of Physics, Old Dominion University, Norfolk, VA 23529-0116 (United States)

    2010-02-01

    We present a short overview of a new method for calculating fully differential cross sections that is able to describe any aspect of coincidence measurements involving heavy projectiles. The method is based upon impact parameter close coupling with pseudostates. Examples from antiproton impact ionization are shown.

  19. A arara-azul-de-Lear, Anodorhynchus leari Bonaparte, 1856

    Directory of Open Access Journals (Sweden)

    Helmut Sick

    1986-01-01

    Full Text Available The case of the Indigo, or Lear's Macaw, Anodorhynchus leari, is unique in South American ornithology. The species, although described more than 100 years ago, was known only through very few living specimens, which entered occasionally the bird trade, without any indication of their origins. It was presumed "probably some part of Brazil" (Salvadori, 1891. The last speculation was that it was unlikely, though not impossible, that the Indigo Macaw might not be an independem species, but rather, a hybrid between the two other well known blue macaws, Anodorhynchus hyacinthinus and A. glaucus (Voous, 1965.

  20. Neutrons from Antiproton Irradiation

    DEFF Research Database (Denmark)

    Bassler, Niels; Holzscheiter, Michael; Petersen, Jørgen B.B.

    the volume targeted for irradiation. A major part of this peripheral dose arise from neutrons, which in particular are problematic due to their high RBE for secondary cancer incidence. We have measured the fast and thermal neutron spectrum in different geometrical configurations in order to experimentally...... the neutron spectrum. Additionally, we used a cylindrical polystyrene loaded with several pairs of thermoluminescent detectors containing Lithium-6 and Lithium-7, which effectively detects thermalized neutrons. The obtained results are compared with FLUKA imulations. Results: The results obtained...... the annihilation vertex inside the polystyrene phantom produced a response which corresponds to a neutron fluence of 8000 neutrons/cm2 per 107 antiprotons. This is equivalent to a neutron kerma of 1.4e-9 Gy (adult brain) per 107 antiprotons following ICRU 46. Conclusion: The thermalized part of the neutron...

  1. Primary population of antiprotonic helium states

    OpenAIRE

    Révai, J.; Shevchenko, N.V.(Nuclear Physics Institute, Řež, 25068, Czech Republic)

    2003-01-01

    A full quantum mechanical calculation of partial cross-sections leading to different final states of antiprotonic helium atom was performed. Calculations were carried out for a wide range of antiprotonic helium states and incident (lab) energies of the antiproton.

  2. Bubble chamber: antiproton annihilation

    CERN Multimedia

    1971-01-01

    These images show real particle tracks from the annihilation of an antiproton in the 80 cm Saclay liquid hydrogen bubble chamber. A negative kaon and a neutral kaon are produced in this process, as well as a positive pion. The invention of bubble chambers in 1952 revolutionized the field of particle physics, allowing real tracks left by particles to be seen and photographed by expanding liquid that had been heated to boiling point.

  3. ALPHA freezes antiprotons

    CERN Multimedia

    CERN Bulletin

    2010-01-01

    Laboratories like CERN can routinely produce many different types of antiparticles. In 1995, the PS210 experiment formed the first antihydrogen atoms and a few years later, in 2002, ATRAP and ATHENA were already able to produce several thousand of them. However, no experiment in the world has succeeded in ‘trapping’ these anti-atoms in order to study them. This is the goal of the ALPHA experiment, which has recently managed to cool down the antiprotons to just a few Kelvin. This represents a major step towards trapping the anti-atom, thus opening a new avenue into the investigation of antimatter properties.   Members of the ALPHA collaboration working on the apparatus in the Antiproton Decelerator experimental hall at CERN. Just like the atom, the anti-atom is neutral. Unlike the atom, the anti-atom is made up of antiprotons (as opposed to protons in the atom) and positrons (as opposed to electrons). In order to thoroughly study the properties of the anti-atoms, scien...

  4. Antiproton compression and radial measurements

    CERN Document Server

    Andresen, G B; Bowe, P D; Bray, C C; Butler, E; Cesar, C L; Chapman, S; Charlton, M; Fajans, J; Fujiwara, M C; Funakoshi, R; Gill, D R; Hangst, J S; Hardy, W N; Hayano, R S; Hayden, M E; Humphries, A J; Hydomako, R; Jenkins, M J; Jorgensen, L V; Kurchaninov, L; Lambo, R; Madsen, N; Nolan, P; Olchanski, K; Olin, A; Page R D; Povilus, A; Pusa, P; Robicheaux, F; Sarid, E; Seif El Nasr, S; Silveira, D M; Storey, J W; Thompson, R I; Van der Werf, D P; Wurtele, J S; Yamazaki, Y

    2008-01-01

    Control of the radial profile of trapped antiproton clouds is critical to trapping antihydrogen. We report detailed measurements of the radial manipulation of antiproton clouds, including areal density compressions by factors as large as ten, achieved by manipulating spatially overlapped electron plasmas. We show detailed measurements of the near-axis antiproton radial profile, and its relation to that of the electron plasma. We also measure the outer radial profile by ejecting antiprotons to the trap wall using an octupole magnet.

  5. Beam Dynamics Studies and Design Optimisation of New Low Energy Antiproton Facilities

    CERN Document Server

    Resta-Lopez, Javier; Welsch, Carsten P

    2016-01-01

    Antiprotons, stored and cooled at low energies in a storage ring or at rest in traps, are highly desirable for the investigation of a large number of basic questions on fundamental interactions. This includes the static structure of antiprotonic atomic systems and the time-dependent quantum dynamics of correlated systems. The Antiproton Decelerator (AD) at CERN is currently the worlds only low energy antiproton factory dedicated to antimatter experiments. New antiproton facilities, such as the Extra Low ENergy Antiproton ring (ELENA) at CERN and the Ultra-low energy Storage Ring (USR) at FLAIR, will open unique possibilities. They will provide cooled, high quality beams of extra-low energy antiprotons at intensities exceeding those achieved presently at the AD by factors of ten to one hundred. These facilities, operating in the energy regime between 100 keV down to 20 keV, face several design and beam dynamics challenges, for example nonlinearities, space charge and scattering effects limiting beam life time....

  6. Treatment Plans for Antiproton Beams

    DEFF Research Database (Denmark)

    Holzscheiter, Michael; Bassler, Niels; Herrmann, Rochus;

    Antiprotons have been proposed as potential modality for particle beam cancer therapy by Gray and Kalogeropoulos in 1985. This proposal was based on the enhancement of physical dose deposition near the end of range due to the annihilation of antiprotons when captured by a nucleus and the expectat...

  7. The PANDA Experiment at FAIR - Subatomic Physics with Antiprotons

    CERN Document Server

    Messchendorp, Johan

    2016-01-01

    The non-perturbative nature of the strong interaction leads to spectacular phenomena, such as the formation of hadronic matter, color confinement, and the generation of the mass of visible matter. To get deeper insight into the underlying mechanisms remains one of the most challenging tasks within the field of subatomic physics. The antiProton ANnihilations at DArmstadt (PANDA) collaboration has the ambition to address key questions in this field by exploiting a cooled beam of antiprotons at the High Energy Storage Ring (HESR) at the future Facility for Antiproton and Ion Research (FAIR) combined with a state-of-the-art and versatile detector. This contribution will address some of the unique features of PANDA that give rise to a promising physics program together with state-of-the-art technological developments.

  8. AA antiproton production target

    CERN Multimedia

    1979-01-01

    The first version of the antiproton production target was a tungsten rod, 11 cm long (actually a row of 11 rods, each 1 cm long) and 3 mm in diameter. The rod was embedded in graphite, pressure-seated into an outer casing made of stainless steel. The casing had fins for forced-air cooling. In this picture, the 26 GeV high-intensity beam from the PS enters from the right, where a scintillator screen, with circles every 5 mm in radius, permits precise aim at the target centre. See also 7903034 and 7905094.

  9. AA antiproton production target

    CERN Multimedia

    1979-01-01

    The first version of the antiproton production target was a tungsten rod, 11 cm long and 3 mm in diameter. The rod was embedded in graphite, pressure-seated into an outer casing of stainless steel. At the entrance to the target assembly was a scintillator screen, imprinted with circles every 5 mm in radius, which allowed to precisely aim the 26 GeV high-intensity proton beam from the PS onto the centre of the target rod. The scintillator screen was a 1 mm thick plate of Cr-doped alumina. See also 7903034 and 7905091.

  10. Thermal excitation of heavy nuclei with 5-15 GeV/c antiproton, proton and pion beams

    CERN Document Server

    Beaulieu, L; Hsi, W C; Lefort, T; Pienkowski, L; Korteling, R G; Wang, G; Back, B B; Bracken, D S; Breuer, H; Cornell, E A; Gimeno-Nogues, F; Ginger, D S; Gushue, S; Huang, M J; Laforest, R; Lynch, W G; Martin, E; Morley, K B; Ramakrishnan, E; Remsberg, L P; Rowland, D; Ruangma, A; Tsang, M B; Viola, V E; Winchester, E M; Xi, H; Yennello, S J

    1999-01-01

    Excitation-energy distributions have been derived from measurements of 5.0-14.6 GeV/c antiproton, proton and pion reactions with $^{197}$Au target nuclei, using the ISiS 4$\\pi$ detector array. The maximum probability for producing high excitation-energy events is found for the antiproton beam relative to other hadrons, $^3$He and $\\bar{p}$ beams from LEAR. For protons and pions, the excitation-energy distributions are nearly independent of hadron type and beam momentum above about 8 GeV/c. The excitation energy enhancement for $\\bar{p}$ beams and the saturation effect are qualitatively consistent with intranuclear cascade code predictions. For all systems studied, maximum cluster sizes are observed for residues with E*/A $\\sim$ 6 MeV.

  11. Laser spectroscopy of antiprotonic helium and pionic helium

    International Nuclear Information System (INIS)

    ASACUSA (Atomic Spectroscopy and Collisions Using Slow Antiproton) experiment of CERN has observed two-photon spectroscopy by making non-linear transitions of the antiprotons which have occupied highly excited levels. The metastable antiproton helium atoms are studied by irradiating two laser light photons propagating in the counter direction. As the result, the spectrum of narrow line width was observed by making the Doppler width of the resonant transition to decrease. And the anti-proton helium transition frequency was measured with the accuracy of (2.3∼5) X10-9. The mass ratio of the antiproton and the electron has been decided to be Mp/me =1836.152674(23) from the comparison of quantum electrodynamics calculation and the present experimental result. The pion-Helium experiment instrument has been also constructed at the ring cyclotron of PSI (Paul Sherer Institute) toward the successful laser spectroscopy of this atom. When this atom is observed, the π- mass can be obtained with the accuracy higher than 6∼8 orders of magnitude which may contribute to the direct measurement of the upper limit value of muon neutrino mass in the Particle Data Book Mass although various difficulties may be encountered. This report describes briefly the laser spectroscopy at first and then the recent situation of the experiments. (S. Funahashi)

  12. High density spiral projection chamber (HDSPC): Design of the end-cap detectors of the OBELIX experiment at LEAR

    International Nuclear Information System (INIS)

    We discuss the design of a cylindrical high density projection chamber that uses the spiral projection chamber geometry and will instrument the end-caps of the proposed OBELIX experiment at LEAR. This detector -high density spiral projection chamber has axial symmetry, radial drift electric field, a radiator made of converter disks alternating with drift volumes and the amplification and readout region in the outer part of the cylinder. It is equipped with FADC electronics and reconstructs in three dimensions primary ionization produced in the active volume. It features fine granularity and high angular resolution near the beam pipe and appears particularly advantageous for γ and prong detection in the forward and very forward region of storage rings and extracted beam experiments. (orig.)

  13. A reservoir trap for antiprotons

    CERN Document Server

    Smorra, Christian; Franke, Kurt; Nagahama, Hiroki; Schneider, Georg; Higuchi, Takashi; Van Gorp, Simon; Blaum, Klaus; Matsuda, Yasuyuki; Quint, Wolfgang; Walz, Jochen; Yamazaki, Yasunori; Ulmer, Stefan

    2015-01-01

    We have developed techniques to extract arbitrary fractions of antiprotons from an accumulated reservoir, and to inject them into a Penning-trap system for high-precision measurements. In our trap-system antiproton storage times > 1.08 years are estimated. The device is fail-safe against power-cuts of up to 10 hours. This makes our planned comparisons of the fundamental properties of protons and antiprotons independent from accelerator cycles, and will enable us to perform experiments during long accelerator shutdown periods when background magnetic noise is low. The demonstrated scheme has the potential to be applied in many other precision Penning trap experiments dealing with exotic particles.

  14. Proton-antiproton collider physics

    CERN Document Server

    Altarelli, Guido

    1989-01-01

    This volume reviews the physics studied at the CERN proton-antiproton collider during its first phase of operation, from the first physics run in 1981 to the last one at the end of 1985. The volume consists of a series of review articles written by physicists who are actively involved with the collider research program. The first article describes the proton-antiproton collider facility itself, including the antiproton source and its principle of operation based on stochastic cooling. The subsequent six articles deal with the various physics subjects studied at the collider. Each article descr

  15. The Antiproton Accumulator (AA)

    CERN Multimedia

    1980-01-01

    Section 06 - 08*) of the AA where the dispersion (and hence the horizontal beam size) is large. One can distinguish (left to right): A vacuum-tank, two bending magnets (BST06 and BST07 in blue) with a quadrupole (QDN07, in red) in between, another vacuum-tank, a wide quadrupole (QFW08) and a further tank . The tanks are covered with heating tape for bake-out. The tank left of BST06 contained the stack core pickup for stochastic cooling (see 7906193, 7906190, 8005051), the two other tanks served mainly as vacuum chambers in the region where the beam was large. Peter Zettwoch works on BST06. *) see: H. Koziol, Antiproton Accumulator Parameter List, PS/AA/Note 84-2 (1984)

  16. S142 set-up to detect X-ray from antiproton-proton atoms (protonium).

    CERN Multimedia

    1978-01-01

    This experiment was designed by the Daresbury-Mainz-TRIUMF Collaboration and was located in the m14 partially separated antiproton beam in the PS South Hall. It used a gaseous hydrogen target, 1 m long, surrounded by a ring of proportional counters, surrounded in turn by a ring of 36 scintillators strips to aid in the annihilation product identification. Ugo Gastaldi (centre)

  17. Elastic and inelastic scattering of 30 MeV and 180 MeV antiprotons on nuclei

    International Nuclear Information System (INIS)

    This thesis reports on the first measurements of angular distributions for elastic and inelastic scattering of antiprotons from nuclei, which have been performed, using the beam delivered by LEAR and the spectrometer SPES II, over a wide angular range and with good precision. Angular distributions for elastic scattering of 50 MeV antiprotons from 12C, 40Ca, 208Pb and 180 MeV antiprotons from 12C, 16O, 18O, 40Ca, 208Pb have been measured. Data on the inelastic 4.4 MeV and 9.6 MeV excited states of 12C and 1.98 MeV excited state of 18O have also been collected. The diffractive angular distributions are first analysed in terms of a fuzzy black disk model, which confirms that the antiproton is strongly absorbed (annihilation) by the nuclei. Optical model analysis, with Woods-Saxon geometry, shows that the real potential is attractive and shallow. The potentials are only determined at the nuclear surface, around the strong absorption radius, where /W(R)/ > 2 /V(R)/. Main characteristics of the antip-nucleus elastic scattering cross sections are well described within microscopic models using the free elementary antiN N interaction, like KMT which have no free parameters. Possibility for test of spin-isospin dependence of the elementary amplitude antiN-N from the measurement of unnatural parity states is also studied

  18. Antiproton Star Observed in Emulsion

    Energy Technology Data Exchange (ETDEWEB)

    Chamberlain, Owen; Chupp, Warren W.; Goldhaber, Gerson; Segre,Emilio; Wiegand, Clyde; Amaldi, E.; Baroni, G.; Castagnoli, C.; Franzinetti, C.; Manfredini, A.

    1955-12-01

    In connection with the antiproton investigation at the Bevatron we planned and carried out a photographic-emulsion exposure in a magnetically selected beam of negative particles. The magnetic system was identical to the first half (one deflecting magnet and one magnetic lens) of the system used in the antiproton experiment of Chamberlain, Segre, Wiegand, and Ypsilantis. The selected particles left the copper target in the forward direction with momentum 1.09 Bev/c.

  19. Elastic scattering, polarization and absorption of relativistic antiprotons on nuclei

    CERN Document Server

    Larionov, A B

    2016-01-01

    We perform Glauber model calculations of the antiproton-nucleus elastic and quasielastic scattering and absorption in the beam momentum range $\\sim 0.5\\div10$ GeV/c. A good agreement of our calculations with available LEAR data and with earlier Glauber model studies of the $\\bar p A$ elastic scattering allows us to make predictions at the beam momenta of $\\sim 10$ GeV/c, i.e at the regime of the PANDA experiment at FAIR. The comparison with the proton-nucleus elastic scattering cross sections shows that the diffractive minima are much deeper in the $\\bar p A$ case due to smaller absolute value of the ratio of the real-to-imaginary part of the elementary elastic amplitude. Significant polarization signal for $\\bar p A$ elastic scattering at 10 GeV/c is expected. We have also revealed a strong dependence of the $\\bar p A$ absorption cross section on the slope parameter of the transverse momentum dependence of the elementary $\\bar pN$ amplitude. The $\\bar p A$ optical potential is discussed.

  20. Seconday-emission profile monitors at LEAR injection

    CERN Multimedia

    1982-01-01

    This is a view against the direction of the beams. Through the right, smaller, opening the beams (protons, antiprotons, H-, later Pb-ions) entered and, after being put on central orbit with septum and kicker, reappeared as circulating beam through the left, larger, opening. Horizontal and vertical position and density profile of the incoming beam were measured with secondary emission grids. The same measurements were made on the beam after it had completed the first turn in the machine. For this purpose it was prevented from circulating with a beam stopper, mounted through the port at left (not mounted at the time the picture was taken).

  1. Search for narrow lines in photon spectra from proton-antiproton annihilations at rest

    International Nuclear Information System (INIS)

    Inclusive photon spectra from annihilation of antiprotons stopped in a liquid hydrogen target were measured at LEAR (CERN) with a magnetic pair spectrometer. The FWHM energy resolution of the spectrometer in the region from 100-700 MeV was in the range from 2 to 4.5%. A total number of about 4.8.106 events with energies up to 1 GeV have been reconstructed. The photon spectra were scanned for possible lines with widths comparable to spectrometer resolution indicating the existence of bound nucleon-antinucleon states. No such structures were found with branching ratios greater than 4 to 8.10-4 at 95% confidence level. Results of former experiments could not be confirmed. (orig.)

  2. Magnetic field measurements in the electron cooling device for LEAR

    International Nuclear Information System (INIS)

    The field of the solenoid magnet to be used in the electron cooling device for LEAR has been investigated by careful field mapping. The magnetic field guiding the electron beam was measured in a volume with a cross-section of 6 x 6 cm2 around the electron beam axis, which is 4.5 m long and bent twice in toroidal sections. A Hall-plate field scanner designed for the mapping of dipole magnets was used to obtain separate field maps of all Cartesian field components in rectangular boxes covering the aforementioned measuring region. For merging these maps into a consistent overall field table, an evaluation procedure has been developed that includes careful survey and the correction of errors inherent in Hall-probe measurements. The measured data are presented in plots of field components and of field lines, and the magnetic field properties of the electron cooling device are discussed. A short description of the computer programs produced during this work is also given. (orig.)

  3. Antiprotonic helium atomcules

    Directory of Open Access Journals (Sweden)

    Sauge Sébastien

    2012-10-01

    Full Text Available About 3% of antiprotons ( stopped in helium are long-lived with microsecond lifetimes, against picoseconds in all other materials. This unusual longevity has been ascribed to the trapping of on metastable bound states in He+ helium atom-molecules thus named atomcules. Apart from their unique dual structure investigated by laser spectroscopy – a near-circular quasi-classical Rydberg atom with l ~ n – 1 ~ 37 or a special diatomic molecule with a negatively charged nucleus in high rotational state with J = l – the chemical physics aspects of their interaction with other atoms or molecules constitute an interesting topic for molecular physics. While atomcules may resist to million collisions in helium, molecular contaminants such as H2 are likely to destroy them in a single one, down to very low temperatures. In the Born-Oppenheimer framework, we interpret the molecular interaction obtained by ab initio quantum chemical calculations in terms of classical reactive channels, with activation barriers accounting for the experiments carried out in He and H2. From classical trajectory Monte Carlo simulations, we show that the thermalization stage strongly quenches initial populations, thus reduced to a recovered 3 % trapping fraction. This work illustrates the pertinence of chemical physics concepts to the study of exotic processes involving antimatter. New insights into the physico-chemistry of cold interstellar radicals are anticipated.

  4. The Antiproton Accumulator (AA)

    CERN Multimedia

    1980-01-01

    A section of the AA where the dispersion (and hence the horizontal beam size) is large. One can distinguish (left to right): A large vacuum-tank, a quadrupole (QDN09*), a bending magnet (BST08), another vacuum-tank, a wide quadrupole (QFW08) and (in the background) a further bending magnet (BST08). The tanks are covered with heating tape for bake-out. The tank left of QDN09 contained the kickers for stochastic pre-cooling (see 790621, 8002234, 8002637X), the other one served mainly as vacuum chamber in the region where the beam was large. Peter Zettwoch works on QFW08. * see: H. Koziol, Antiproton Accumulator Parameter List, PS/AA/Note 84-2 (1984) See under 7911303, 7911597X, 8004261 and 8202324. For photos of the AA in different phases of completion (between 1979 and 1982) see: 7911303, 7911597X, 8004261, 8004608X, 8005563X, 8005565X, 8006716X, 8006722X, 8010939X, 8010941X, 8202324, 8202658X, 8203628X .

  5. Enhancing trappable antiproton populations through deceleration and frictional cooling

    Energy Technology Data Exchange (ETDEWEB)

    Zolotorev, Max; Sessler, Andrew; Penn, Gregory; Wurtele, Jonathan S.; Charman, Andrew E.

    2012-03-20

    CERN currently delivers antiprotons for trapping experiments with the Antiproton Decelerator (AD), which slows the antiprotons down to about 5 MeV.This energy is currently too high for direct trapping, and thick foils are used to slow down the beam to energies which can be trapped.To allow further deceleration to $\\sim 100 \\;\\mbox{keV}$, CERN is initiating the construction of ELENA,consisting of a ring which will combine RF deceleration and electron cooling capabilities. We describe a simple frictionalcooling scheme that can serve to provide significantly improved trapping efficiency, either directly from the AD or first usinga standard deceleration mechanism (induction linac or RFQ). This scheme could be implemented in a short time.The device itself is short in length, uses accessible voltages, and at reasonable cost could serve in the interim beforeELENA becomes operational, or possibly in lieu of ELENA for some experiments. Simple theory and simulations provide a preliminary assessment of theconcept and its strengths and limitations, and highlight important areas for experimental studies, in particular to pin down the level of multiplescattering for low-energy antiprotons. We show that the frictional cooling scheme can provide a similar energy spectrum to that of ELENA,but with higher transverse emittances.

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

    CERN Document Server

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

    2001-01-01

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

  7. ASACUSA Anti-protonic Helium_Final

    CERN Multimedia

    CERN Audiovisual Production Service; CERN AD; Paola Catapano; Julien Ordan, Arzur Catel; Paola Catapano; ASACUSA COLLABORATION

    2016-01-01

    Latest precision measurement of the mass of the proton and the anti proton though the production of antiprotonic helium by the ASACUSA experiment at CERN's antimatter factory, with a beam from the Antiproton Decelerator

  8. Nuclear dynamics induced by antiprotons

    CERN Document Server

    Feng, Zhao-Qing

    2015-01-01

    Reaction dynamics in collisions of antiprotons on nuclei is investigated within the Lanzhou quantum molecular dynamics model. The reaction channels of elastic scattering, annihilation, charge exchange and inelastic collisions of antiprotons on nucleons have been included in the model. Dynamics on particle production, in particular pions, kaons, antikaons and hyperons, is investigated in collisions of $\\overline{p}$ on $^{12}$C, $^{20}$Ne, $^{40}$Ca and $^{181}$Ta from a low to high incident momenta. It is found that the annihilations of $\\overline{p}$ on nucleons are of importance on the dynamics of particle production in phase space. Hyperons are mainly produced via meson induced reactions on nucleons and strangeness exchange collisions, which lead to the delayed emission in antiproton-nucleus collisions.

  9. Antiprotons in the Cosmic Rays

    Science.gov (United States)

    Nutter, Scott

    1999-10-01

    The HEAT (High Energy Antimatter Telescope) collaboration flew in May 1999 a balloon-borne instrument to measure the relative abundance of antiprotons and protons in the cosmic rays to kinetic energies of 30 GeV. The instrument uses a multiple energy loss technique to measure the Lorentz factor of through-going cosmic rays, a magnet spectrometer to measure momentum, and several scintillation counters to determine particle charge and direction (up or down in the atmosphere). The antiproton/proton abundance ratio as a function of energy is a probe of the propagation environment of protons through the galaxy. Existing measurements indicate a higher than expected value at both high and low energies. A confirming measurement could indicate peculiar antiproton sources, such as WIMPs or supersymmetric darkmatter candidates. A description of the instrument, details of the flight and instrument performance, and status of the data analysis will be given.

  10. Measurement of interaction between antiprotons

    CERN Document Server

    ,

    2015-01-01

    One of the primary goals of nuclear physics is to understand the force between nucleons, which is a necessary step for understanding the structure of nuclei and how nuclei interact with each other. Rutherford discovered the atomic nucleus in 1911, and the large body of knowledge about the nuclear force since acquired was derived from studies made on nucleons or nuclei. Although antinuclei up to antihelium-4 have been discovered and their masses measured, we have no direct knowledge of the nuclear force between antinucleons. Here, we study antiproton pair correlations among data taken by the STAR experiment at the Relativistic Heavy Ion Collider and show that the force between two antiprotons is attractive. In addition, we report two key parameters that characterize the corresponding strong interaction: namely, the scattering length (f0) and effective range (d0). As direct information on the interaction between two antiprotons, one of the simplest systems of antinucleons, our result provides a fundamental ingr...

  11. Antiproton collisions with molecular hydrogen

    DEFF Research Database (Denmark)

    Lühr, Armin Christian; Saenz, Alejandro

    2008-01-01

    Theoretical antiproton and proton cross sections for ionization and excitation of hydrogen molecules as well as energy spectra of the ionized electrons were calculated in the impact-energy range from 8  to  4000  keV. The cross sections were computed with the close-coupling formulation of the sem......Theoretical antiproton and proton cross sections for ionization and excitation of hydrogen molecules as well as energy spectra of the ionized electrons were calculated in the impact-energy range from 8  to  4000  keV. The cross sections were computed with the close-coupling formulation...

  12. Proton-Antiproton Collider Physics

    OpenAIRE

    Shochet, Melvyn J.

    1995-01-01

    Comment: Summary of the 10th Topical Workshop on Proton-Antiproton Collider Physics, Fermilab, May 9-13, 1995. Postscript file (34 pages with 82 embedded figures; 5.7 MB) available at http://www-cdf.fnal.gov/physics/conf95/cdf3225_pbarp_wkshp_summary.ps

  13. Physics at CERN's Antiproton Decelerator

    CERN Document Server

    Hori, M

    2013-01-01

    The Antiproton Decelerator of CERN began operation in 1999 to serve experiments for studies of CPT invariance by precision laser and microwave spectroscopy of antihydrogen ($\\bar{\\rm H}$) and antiprotonic helium ($\\bar{p}{\\rm He}^+$). The first 12 years of operation saw cold $\\bar{\\rm H}$ synthesized by overlapping clouds of positrons ($e^+$) and antiprotons ($\\bar{p}$) confined in magnetic Penning traps. Cold $\\bar{\\rm H}$ was also produced in collisions between Rydberg positronium atoms and $\\bar{p}$. Ground-state $\\bar{\\rm H}$ was later trapped for up to $\\sim 1000$ s in a magnetic bottle trap, and microwave transitions excited between its hyperfine levels. In the $\\bar{p}{\\rm He}^+$ atom, UV transitions were measured to a precision of (2.3-5) $\\times$ $10^{-9}$ by sub-Doppler two-photon laser spectroscopy. From this the antiproton-to-electron mass ratio was determined as $M_{\\bar{p}}/m_e=$1836.1526736(23), which agrees with the p value. Microwave spectroscopy of $\\bar{p}{\\rm He}^+$ yielded a measurement o...

  14. Status of antiproton accumulation and cooling at Fermilab's Recycler

    Energy Technology Data Exchange (ETDEWEB)

    Prost, L.R.; Bhat, C.M.; Broemmelsiek, D.; Burov, A.; Carlson, K.; Crisp, J.; Derwent, P.; Eddy, N.; Gattuso, C.; Hu, M.; Pruss, S.; /Fermilab

    2009-08-01

    The Recycler ring is an 8 GeV permanent magnet storage ring where antiprotons are accumulated and prepared for Fermilab's Tevatron Collider program. With the goal of maximizing the integrated luminosity delivered to the experiments, storing, cooling and extracting antiprotons with high efficiency has been pursued. Over the past two years, while the average accumulation rate doubled, the Recycler continued to operate at a constant level of performance thanks to changes made to the Recycler Electron Cooler (energy stability and regulation, electron beam optics), RF manipulations and operating procedures. In particular, we discuss the current accumulation cycle in which {approx} 400 x 10{sup 10} antiprotons are accumulated and extracted to the Tevatron every {approx}15 hours.

  15. X-rays from antiprotonic sup 3 He and sup 4 He

    Energy Technology Data Exchange (ETDEWEB)

    Schneider, M.; Bacher, R.; Bluem, P.; Gotta, D.; Heitlinger, K.; Kunold, W.; Rohmann, D. (Kernforschungszentrum Karlsruhe GmbH (Germany, F.R.). Inst. fuer Kernphysik Karlsruhe Univ. (T.H.) (Germany, F.R.). Inst. fuer Experimentelle Kernphysik); Egger, J.; Simons, L.M. (Paul Scherrer Inst. (PSI), Villigen (Switzerland)); Elsener, K. (European Organization for Nuclear Research, Geneva (Switzerland))

    1991-02-01

    Antiprotonic X-rays from the helium isotopes have been observed at pressures of 36, 72, 375 and 600 mbar. The antiproton beam from LEAR with momenta of 309 and 202 MeV/c has been stopped at these pressures using the cyclotron trap. The X-rays were detected with Si(Li) and intrinsic Ge semiconductor detectors. Absolute X-ray yields were determined and the strong-interaction 2p shifts and the 2p and 3d broadenings measured to be {epsilon}{sub 2p}=(-17{plus minus}4) eV, {Gamma}{sub 2p}=(25{plus minus}9) eV and {Gamma}{sub 3d}=(2.14{plus minus}0.18) meV for anti p{sup 3}He and {epsilon}{sub 2p}=(-18{plus minus}2) eV, {Gamma}{sub 2p}=(45{plus minus}5) eV and {Gamma}{sub 3d}=(2.36{plus minus}0.10) meV for anti p{sup 4}He. (orig.).

  16. Precision Measurement of the Energies and Line Shapes of Antiprotonic Lyman and Balmer Transitions From Hydrogen and Helium Isotopes

    CERN Multimedia

    2002-01-01

    % PS207 \\\\ \\\\ For the study of the antiproton-proton and antiproton-nuclear spin-spin and spin-orbital interaction at threshold a high resolution measurement is proposed of the line shapes and energy shifts of antiprotonic K$\\alpha$ and L$\\alpha$ transitions of hydrogen and helium isotopes. The intense LEAR beam, stopped in the cyclotron trap at low gas pressure, provides a unique~X-ray~source with sufficient brightness. Charge coupled devices with their excellent background rejection and energy resolution allow a precise determination of the strong shifts and widths of the 1s hyperfine states of protonium, in addition the detection of the $\\bar{p}$D K$\\alpha$ transition should be possible. A focussing crystal spectrometer with a resolution $\\Delta$E/E of about l0$ ^- ^{4} $, which is superior in the accuracy of the energy determination by two orders of magnitude as compared to the present detection methods, will be used to measure the energies of the L$\\alpha$ transitions. This permits a first direct measure...

  17. Study of $ \\bar{p} $ and $ \\bar{n} $ annihilations at LEAR with OBELIX, a large acceptance and high resolution detector based on the Open Axial Field Spectrometer

    CERN Multimedia

    2002-01-01

    % PS201 Study of $\\bar{p}$ and $\\bar{n}$ annihilations at LEAR with OBELIX, a large acceptance and high resolution detector based on the Open Axial Field Spectrometer \\\\ \\\\OBELIX is designed to study exclusive final states of antiproton and antineutron annihilations at low energies with protons and nuclei. \\\\ \\\\The physics motivations of the experiment are:\\\\ \\\\\\begin{itemize} \\item (gg, ggg), hybrids ($ q \\bar{q} g $), multiquarks ($ q q \\bar{q} \\bar{q} $) and light mesons ($ q \\bar{q} $) produced in $ N \\bar{N} $ annihilations and study of their spectroscopy and decays. Also broad structures will be searched for by comparing identical decay modes in exclusive final states of the same type occuring from initial states with different angular momentum or isospin. \\item Study of the dynamics of $ N \\bar{N} $ interactions and of the dependence of the final and intermediate resonant states of annihilation upon the quantum numbers of the initial $ N \\bar{N} $ state (angular momentum: S and P-wave in $\\bar{p}p $ at...

  18. ‘Crack Nature’s Molds’: Reasoned Madness and Evolution in King Lear

    Directory of Open Access Journals (Sweden)

    Matthew Smith

    2015-06-01

    Full Text Available King Lear as a product of evolutionary progressions is logical because the play is framed around two ideas of society and generation in direct confrontation. The sociopolitical ramifications of King Lear are clarified when viewed as an evolutionary progression because societal causality is mirrored in nature. The connection between Lear’s madness and nature’s role in determining societal evolution is demonstrated in the evolutionary notion that “everybody is what he typically is because his progenitors were what they were . . . [i]n the molecular structure of the minute germ of him,” (Maudsley 4 and that and social events are connected with the mechanistic march of nature. When Lear bellows “Crack nature’s molds, all germens spill at once,” (3.2.8 he is requesting the impossible, that the laws of causation be terminated and evolution be put on hold.Keywords: Evolutionary Criticism, reason, philosophy, Shakespeare, King Lear, consilience, evolution, mechanism, madness, nature

  19. JETSET: Physics at LEAR with an Internal Gas Jet Target and an Advanced General Purpose Detector

    CERN Multimedia

    2002-01-01

    This experiment involves an internal gas cluster jet target surrounded by a compact general-purpose detector. The LEAR beam and internal jet target provide several important experimental features: high luminosity $ ( 10 ^{3} ^0 $ cm$^- ^{2} $ sec$^- ^{1} ) $, excellent mass resolution ($\\Delta

  20. The karyotype of the critically endangered Lear's macaw, Anodorhynchus leari Bonaparte 1856 (Aves, Psittaciformes)

    OpenAIRE

    Denise Monnerat Nogueira; Lucia Moreno de Souza; Beatriz Goldschmidt; Christiano Pinheiro da Silva; Denise Wilches Monsores

    2006-01-01

    We used conventional chromosomal staining to describe the karyotype of the critically endangered Lear's macaw, Anodorhynchus leari Bonaparte 1856. A diploid number of 2n = 70 and a karyotype similar to that of its congener Anodorhynchus hyacinthinus suggests that chromosomal rearrangements were not the main evolutionary mechanism in the genus.

  1. “The Thing Itself” Ironic Hermeneutics of the Subject in King Lear

    Directory of Open Access Journals (Sweden)

    Sergej Macura

    2009-07-01

    Full Text Available Cet article examine le processus de “connaissance de soi” conduit par le protagoniste principal de la pièce de Shakespeare, Le Roi Lear, à travers les dialogues du personnage éponyme avec les interlocuteurs divers de la pièce – les membres de sa famille, ses domestiques, ses camarades de souffrance sur la lande, mais aussi les forces de la nature. Son savoir le plus profond dérive de sa rencontre avec Edgar, déguisé en “pauvre Tom”, alors que Lear finalement devient fou, après avoir compris la misère qu’il s’est fait subir à lui-même.The paper discusses the process of self-knowing experienced by the main character in King Lear, through the self-deposed King’s dialogues with various protagonists of the play – his closest relatives, his servants, fellow-sufferers on the heath and even the forces of nature. His deepest knowledge comes from the encounter with Edgar in the disguise of Poor Tom, when his reason finally gives way before he can realize what he has done to himself.Este artículo examina el proceso de “conocimiento de sí” que vive el protagonista de la obra de Shakespeare El Rey Lear, mediante los diálogos del personaje epónimo con distintos interlocutores de la obra (los miembros de su familia, sus domésticos, sus compañeros de sufrimiento en la landa, así como las fuerzas de la naturaleza. Su saber más profundo nace del encuentro con Edgar, disfrazado de “pobre Tom”, que tiene lugar en el momento en que Lear acaba por volverse loco, después de darse cuenta de lo que se hizo vivir a si mismo.

  2. Example of an Antiproton-Nucleon Annihilation

    Energy Technology Data Exchange (ETDEWEB)

    Chamberlain, O.; Chupp, W.W.; Ekspong, A.G.; Goldhaber, G.; Goldhaber, S.; Lofgren, E.J.; Segre, E.; Wiegand, C.; Amaldi, E.; Baroni,G.; Castagnoli, C.; Franzinetti, C.; Manfredini, A.

    1956-02-27

    The existence of antiprotons has recently been demonstrated at the Berkeley Bevatron by a counter experiment. The antiprotons were found among the momentum-analyzed (1190 Mev/c) negative particles emitted by a copper target bombarded by 6.2-Bev protons. Concurrently with the counter experiment, stacks of nuclear emulsions were exposed in the beam adjusted to 1090 Mev/c negative particles in an experiment designed to observe the properties of antiprotons when coming to rest. This required a 132 g/cm2 copper absorber to slow down the antiprotons sufficiently to stop them in the emulsion stack. Only one antiproton was found in stacks in which seven were expected, assuming a geometric interaction cross section for antiprotons in copper. It has now been found that the cross section in copper is about twice geometric, which explains this low yield.

  3. Antiproton source beam position system

    International Nuclear Information System (INIS)

    The TeV I Beam Position Monitor (BPM) system is designed to provide a useful diagnostic tool during the commissioning and operational phases of the antiproton source. Simply stated the design goal is to provide single turn position information for intensities of > 1x109 particles, and multi-turn (clocked orbit) information for beam intensities of > 1x107 particles, both with sub-millimeter resolution. It is anticipated that the system will be used during commissioning for establishing the first turn through the Debuncher and Accumulator, for aligning injection orbits, for providing information necessary to correct closed orbits, and for measuring various machine parameters (e.g. tunes, dispersion, aperture, chromaticity). During normal antiproton operation the system will be used to monitor the beam position throughout the accumulation process

  4. Antiproton radiation found effective in cancer research

    CERN Multimedia

    2003-01-01

    "An international collaboration of scientists has completed the first ever antiproton beam experiments designed to reveal the biological effectiveness of antiproton radiation in terminating cells used for cancer research...PBar Labs assembled the collaboration at CERN (European Organization for Nuclear Research in Geneva) to perform the measurements" (1 page).

  5. Study of Anti-Hydrogen and Plasma Physics 4.Observation of Antiproton Beams and Nonneutral Plasmas

    CERN Document Server

    Hori, Masaki; Fujiwara, Makoto; Kuroda, Naofumi

    2004-01-01

    Diagnostics of antiproton beams and nonneutral plasmas are described in this chapter. Parallel plate secondary electron emission detectors are used to non-destructively observe the beam position and intensity without loss. Plastic scintillation tracking detectors are useful in determining the position of annihilations of antiprotons in the trap. Three-dimensional imaging of antiprotons in a Penning trap is discussed. The unique capability of antimatter particle imaging has allowed the observation of the spatial distribution of particle loss in a trap. Radial loss is localized to small spots, strongly breaking the azimuthal symmetry expected for an ideal trap. By observing electrostatic eigen-modes of nonneutral plasmas trapped in the Multi-ring electrode trap, the non-destructive measurement of plasma parameters is performed.

  6. That was LEAP 05! or Antiproton Physics in a Nutshell

    Science.gov (United States)

    Kienle, Paul

    2005-10-01

    A personally flavored review of selected topics of LEAP 05 is given, with focus on some recent interesting developments in low and medium energy antiproton physics, such as fundamental symmetries and antihydrogen, antihadron-hadron systems, antiproton-proton annihilation, nuclear structure studies with antiprotons, and the FAIR facility for antiproton and ion research.

  7. Interaction of antiproton with nuclei

    CERN Document Server

    Hrtánková, J

    2015-01-01

    We performed fully self-consistent calculations of $\\bar{p}$-nuclear bound states within the relativistic mean-field (RMF) model. The G-parity motivated $\\bar{p}$-meson coupling constants were adjusted to yield potentials consistent with $\\bar{p}$-atom data. We confirmed large polarization effects of the nuclear core caused by the presence of the antiproton. The $\\bar{p}$ absorption in the nucleus was incorporated by means of the imaginary part of a phenomenological optical potential. The phase space reduction for the $\\bar{p}$ annihilation products was taken into account. The corresponding $\\bar{p}$ width in the medium significantly decreases, however, it still remains considerable for the $\\bar{p}$ potential consistent with experimental data.

  8. Antiproton Induced Fission and Fragmentation of Nuclei

    CERN Multimedia

    2002-01-01

    The annihilation of slow antiprotons with nuclei results in a large highly localized energy deposition primarily on the nuclear surface. \\\\ \\\\ The study of antiproton induced fission and fragmentation processes is expected to yield new information on special nuclear matter states, unexplored fission modes, multifragmentation of nuclei, and intranuclear cascades.\\\\ \\\\ In order to investigate the antiproton-nucleus interaction and the processes following the antiproton annihilation at the nucleus, we propose the following experiments: \\item A)~Measurement of several fragments from fission and from multifragmentation in coincidence with particle spectra, especially neutrons and kaons. \\item B)~Precise spectra of $\\pi$, K, n, p, d and t with time-of-flight techniques. \\item C)~Installation of the Berlin 4$\\pi$ neutron detector with a 4$\\pi$ Si detector placed inside for fragments and charged particles. This yields neutron multiplicity distributions and consequently distributions of thermal excitation energies and...

  9. Prospects for Antiproton Experiments at Fermilab

    CERN Document Server

    Kaplan, Daniel M

    2011-01-01

    Fermilab operates the world's most intense antiproton source. Newly proposed experiments can use those antiprotons either parasitically during Tevatron Collider running or after the end of the Tevatron Collider program. For example, the annihilation of 5 to 8 GeV antiprotons is expected to yield world-leading sensitivities to hyperon rare decays and CP violation. It could also provide the world's most intense source of tagged D^0 mesons, and thus the best near-term opportunity to study charm mixing and, via CP violation, to search for new physics. Other measurements that could be made include properties of the X(3872) and the charmonium system. An experiment using a Penning trap and an atom interferometer could make the world's most precise measurement of the gravitational force on antimatter. These and other potential measurements using antiprotons offer a great opportunity for a broad and exciting physics program at Fermilab in the post-Tevatron era.

  10. Facility for Antiproton and Ion Research, FAIR, at the GSI site

    Science.gov (United States)

    Rosner, Guenther

    2006-11-01

    FAIR is a new large-scale particle accelerator facility to be built at the GSI site in Germany. The research pursued at FAIR will cover a wide range of topics in nuclear and hadron physics, as well as high density plasma physics, atomic and antimatter physics, and applications in condensed matter physics and biology. The working horse of FAIR will be a 1.1km circumference double ring of rapidly cycling 100 and 300Tm synchrotrons, which will be used to produce high intensity secondary beams of short-lived radioactive ions or antiprotons. A subsequent suite of cooler and storage rings will deliver heavy ion and antiproton beams of unprecedented quality. Large experimental facilities are presently being designed by the NUSTAR, PANDA, PAX, CBM, SPARC, FLAIR, HEDgeHOB and BIOMAT collaborations.

  11. The antiproton depth–dose curve in water

    CERN Document Server

    Bassler, N; Jäkel, O; Knudsen, H V; Kovacevic, S

    2008-01-01

    We have measured the depth–dose curve of 126 MeV antiprotons in a water phantom using ionization chambers. Since the antiproton beam provided by CERN has a pulsed structure and possibly carries a high-LET component from the antiproton annihilation, it is necessary to correct the acquired charge for ion recombination effects. The results are compared with Monte Carlo calculations and were found to be in good agreement. Based on this agreement we calculate the antiproton depth–dose curve for antiprotons and compare it with that for protons and find a doubling of the physical dose in the peak region for antiprotons.

  12. Antiproton Radiotherapy Peripheral Dose from Secondary Neutrons produced in the Annihilation of Antiprotons in the Target

    CERN Document Server

    Fahimian, Benjamin P; Keyes, Roy; Bassler, Niels; Iwamoto, Keisuke S; Zankl, Maria; Holzscheiter, Michael H

    2009-01-01

    The AD-4/ACE collaboration studies the biological effects of antiprotons with respect to a possible use of antiprotons in cancer therapy. In vitro experiments performed by the collaboration have shown an enhanced biological effectiveness for antiprotons relative to protons. One concern is the normal tissue dose resulting from secondary neutrons produced in the annihilation of antiprotons on the nucleons of the target atoms. Here we present the first organ specific Monte Carlo calculations of normal tissue equivalent neutron dose in antiproton therapy through the use of a segmented CT-based human phantom. The MCNPX Monte Carlo code was employed to quantify the peripheral dose for a cylindrical spread out Bragg peak representing a treatment volume of 1 cm diameter and 1 cm length in the frontal lobe of a segmented whole-body phantom of a 38 year old male. The secondary neutron organ dose was tallied as a function of energy and organ.

  13. Tests of CP Violation with $\\bar{K^0}$ and $ K^{0} $ at LEAR

    CERN Multimedia

    2002-01-01

    % PS195 Tests of CP Violation with &bar.K$^0$ and K$^0$ at LEAR \\\\ \\\\The aim of the experiment is to carry out precision tests of CP, T and CPT on the neutral kaon system through $ K ^0 - $\\bar{K}^0 $ interferometry using LEAR as an intense source. A beam of $ ~10^{6}~\\bar{p}$~events/second is brought to rest in a hydrogen target producing $ K ^0 $ and $ $\\bar{K}^0 $ events through the reaction channels : \\\\ \\\\ \\begin{center} $\\bar{p}p~~~~~\\rightarrow~~~~K^0~+~(K^-\\pi^+$) \\\\ \\\\~~~~~~~~$\\rightarrow~~~~\\bar{K}^0~+~(K^+\\pi^-$) \\end{center}\\\\ \\\\The neutral strange particles and their antiparticles are tagged by detecting in the magnetic field the sign of the accompanying charged kaons identified via Cerenkovs and scintillators. The experiment has the unique feature that the decays from particles and antiparticles are recorded under the same operating conditions using tracking chambers and a gas sampling electromagnetic calorimeter. The measured time-dependent $ K ^0 $-$ $\\bar{K}^0 $ asymmetries for non-lepton...

  14. Antiprotons four times more effective than protons for cell irradiation

    CERN Multimedia

    2007-01-01

    "A pioneering experiment at CERN with potential future application in cancer therapy has produced its first results. Started in 2003, ACE (Antiproton Cell Experiment) is the first investigation of the biological effects of antiprotons." (1,5 page)

  15. Antiprotons four times more effective than protons for cell irradiation

    CERN Multimedia

    2006-01-01

    "A pioneering experiment at CERN with potential future application in cancer therapy has produced its first results. Started in 2003, ACE (Antiproton Cell Experiment) is the first investigation of the biological effects of antiprotons." (1,5 page)

  16. Colliding beam physics at Fermilab: interaction regions, beam storage, antiproton cooling, production, and colliding

    Energy Technology Data Exchange (ETDEWEB)

    Walker, J.K. (ed.)

    1977-01-01

    The purpose of the colliding beams experment department at Fermilab was to bring about collisions of the stored beams in the energy doubler/saver and main ring, and construct experimental areas with appropriate detectors. To explore the feasibility of using the main ring as a storage device, several studies were carried out to investigate beam growth, loss, and the backgrounds in detectors at possible intersection regions. This range of developments constituted the major topics at the 1977 Summer Study reported here. Emphasis in part one is on interaction regions, beam storage, antiproton cooling, production, and colliding. 40 papers from this part are included in the data base. (GHT)

  17. The HEAT Cosmic Ray Antiproton Experiment

    Science.gov (United States)

    Nutter, Scott

    1998-10-01

    The HEAT (High Energy Antimatter Telescope) collaboration is constructing a balloon-borne instrument to measure the relative abundance of antiprotons and protons in the cosmic rays to kinetic energies of 30 GeV. The instrument uses a multiple energy loss technique to measure the Lorentz factor of through-going cosmic rays, a magnet spectrometer to measure momentum, and several scintillation counters to determine particle charge and direction (up or down in the atmosphere). The antiproton to proton abundance ratio as a function of energy is a probe of the propagation environment of protons through the galaxy. Existing measurements indicate a higher than expected value at both high and low energies. A confirming measurement could indicate peculiar antiproton sources, such as WIMPs or supersymmetric darkmatter candidates.

  18. Low energy antiproton possibilities at the AGS

    International Nuclear Information System (INIS)

    The technical feasibility of creating a pure antiproton beam at the AGS has been studied. The scheme involves an antiproton target station and transport back to the Booster synchrotron, which acts as both a purifier and accelerator/decelerator. This proposal would be very attractive to the user community since this operation could run parasitically (transparently) to the AGS operating modes. The energy range of antiprotons can be as low as 2 MeV to as high as 5 GeV. The intensity of the beam is estimated to be 7 x 107/sec above 2.5 GeV/c and 4 x 104/sec at 200 MeV/c

  19. K-shell ionization by antiprotons

    International Nuclear Information System (INIS)

    We present first calculations for the impact parameter dependence of K-shell ionization rates in anti pCu and in anti pAg collisions at various projectile energies. We show that the effect of the attractive Coulomb potential on the Rutherford trajectory and the anti-binding effect caused by the negative charge of the antiproton result in a considerable increase of the ionization probability. Total ionization cross-sections for proton and antiproton projectiles are compared with each other and with experimental ionization cross-sections for protons. (orig.)

  20. K-shell ionization by antiprotons

    Energy Technology Data Exchange (ETDEWEB)

    Mehler, G.; Mueller, B.; Greiner, W.; Soff, G.

    1987-08-01

    We present calculations for the impact-parameter dependence of K-shell ionization rates in p-bar-Cu and in p-bar-Ag collisions at various projectile energies. We show that the effect of the attractive Coulomb potential on the Rutherford trajectory and the antibinding effect caused by the negative charge of the antiproton result in a considerable increase of the ionization probability. Total ionization cross sections for proton and antiproton projectiles are compared with each other and with experimental ionization cross sections for protons.

  1. The ASACUSA experiment at CERN's AD antiproton decelerator catches antiprotons in helium, where the antiprotons replace electrons, giving exotics atoms.

    CERN Multimedia

    Loïez, P

    2000-01-01

    Photo 03: Laser beams are prepared for shooting at antiprotonic helium atoms. Left to right: Masaki Hori (Tokyo University) and John Eades (CERN). Photo 01: Dye laser triggered by "YAG" laser. Photo 02: Masaki Hori adjusting optical system of laser beams.

  2. The Antiproton Depth-Dose Curve in Water

    DEFF Research Database (Denmark)

    Bassler, Niels; Holzscheiter, Michael; Jäkel, Oliver;

    2008-01-01

    We have measured the depth-dose curve of 126 MeV antiprotons in a water phantom using ionization chambers. Since the antiproton beam provided by CERN has a pulsed structure and possibly carries a high-LET component from the antiproton annihilation, it is necessary to correct the acquired charge...... for ion recombination effects. The results are compared with Monte Carlo calculations and were found to be in good agreement. Finally we compare the antiproton depth-dose curve with that of protons, and find a doubling of the physical dose in the peak region for antiprotons....

  3. Antiproton-proton resonant like channels in J/Psi decays into photon, proton and antiproton

    CERN Document Server

    Loiseau, B

    2005-01-01

    The BES collaboration has recently observed a strong enhancement close to the proton-antiproton threshold in the J/Psi decays into photon, proton and antiproton. Such a structure can be explained by a traditional nucleon-antinucleon model. The near threshold 1S0 bound state and/or the well-established 3P0 resonant state found in this nucleon-antinucleon interaction can adequately describe the BES data.

  4. A Cryogenic Current Comparator for the Low Energy Antiproton Facilities at CERN

    CERN Document Server

    Fernandes, M; Welsch, CP

    2014-01-01

    Several laboratories have shown the potential of using Superconducting QUantum Interference Device (SQUID) magnetometers together with superconductor magnetic shields to measure beam current intensities in the submicro-Ampere regime. CERN, in collaboration with GSI, Jena university and Helmholtz Institute Jena, is currently working on developing an improved version of such a current monitor for the Antiproton Decelerator (AD) and Extra Low ENergy Antiproton (ELENA) rings at CERN, aiming for better current resolution and overall system availability. This contribution will present the current design, including theoretical estimation of the current resolution; stability limits of SQUID systems and adaptation of the coupling circuit to the AD beam parameters; the analysis of thermal and mechanical cryostat modes.

  5. Ionization in antiproton-hydrogen collisions

    International Nuclear Information System (INIS)

    Employing the semiclassical approximation we calculate within the coupled-state formalism the ionization probability in antiproton-hydrogen (anti p+H) collisions. In particular we investigate the adiabatic ionization at the distance of closest approach in almost central collisions. Striking differences in the electron excitation probability compared with proton-hydrogen (p+H) collisions are predicted. (orig.)

  6. Calculated LET-Spectrum of Antiprotons

    DEFF Research Database (Denmark)

    Bassler, Niels

    -LET components resulting from the annihilation. Though, the calculations of dose-averaged LET in the entry region may suggest that the RBE of antiprotons in the plateau region could significantly differ from unity. Materials and Methods Monte Carlo simulations using FLUKA were performed for calculating...

  7. The biological effectiveness of antiproton irradiation

    DEFF Research Database (Denmark)

    Holzscheiter, Michael H.; Bassler, Niels; Agazaryan, Nzhde;

    2006-01-01

    Background and purpose: Antiprotons travel through tissue in a manner similar to that for protons until they reach the end of their range where they annihilate and deposit additional energy. This makes them potentially interesting for radiotherapy. The aim of this study was to conduct the first e...

  8. Collisions of antiprotons with hydrogen molecular ions

    DEFF Research Database (Denmark)

    Lühr, Armin Christian; Saenz, Alejandro

    2009-01-01

    Time-dependent close-coupling calculations of the ionization and excitation cross section for antiproton collisions with molecular hydrogen ions are performed in an impact energy range from 0.5 keV to 10 MeV. The Born-Oppenheimer and Franck-Condon approximations as well as the impact parameter...

  9. Study of Interaction of Low-Energy Antiprotons with H$^{2}$,He$^{3}$,He$^{4}$,Ne-Nuclei Using a Streamer Chamber in Magnetic Field

    CERN Multimedia

    2002-01-01

    The aim of this experiment is the systematic study of the interaction between low-energy antiprotons and the H|2,~He|3,~He|4,~Ne-nuclei using a self shunted streamer chamber in a magnetic field exposed to the antiproton beam of the LEAR facility. The properties of the self shunted streamer chamber, which allows the use of the filling gas (hydrogen, helium, neon at a pressure of l~atm) as a target, permit to carry out experiments also in the very low-energy region. \\\\ \\\\ The experimental apparatus is suitable for a large programme of measurements. We plan to measure the @*H|2 cross section and the spectator momentum distributions at @* momenta lower than 250~MeV/c, where data are lacking. It is interesting to study for the first time the @*He|3 and @*He|4 interactions measuring the cross sections and the emitted particle distributions. Among other things the knowledge of the branching ratio of the @*He|4 annihilation channels clarifies some open cosmological questions. The study of the process of nuclear absor...

  10. Protonium X-ray spectroscopy

    CERN Document Server

    Gotta, D

    1999-01-01

    The Lyman and Balmer transitions from antiprotonic hydrogen and deuterium were studied extensively at the low-energy-antiproton ring LEAR at CERN in order to determine the strong interaction effects. A first series of experiments $9 was performed with semiconductor and gaseous X-ray detectors. In the last years of LEAR operation using a Bragg crystal spectrometer, strong interaction parameters in the 2p states of antiprotonic hydrogen and deuterium were measured $9 directly. The results of the measurements support the meson-exchange models describing the medium and long range part of the nucleon-antinucleon interaction. (39 refs).

  11. Twitter, King Lear, and the Freedom of Speech, by John Curtis, and Judicial Allusion as Ornament: A Response to John Curtis’s, ‘Twitter, King Lear, and the Freedom of Speech’ by Professor Gary Watt

    Directory of Open Access Journals (Sweden)

    John Curtis

    2014-03-01

    Full Text Available On 27 July 2012, in his judgment following ‘The Twitter Joke Trial’, the Lord Chief Justice of England & Wales quoted from King Lear (Folio.  The trial was the first time a British Court had considered the use of Twitter in the context of a bomb hoax.  The judgment was hailed as ‘a victory for common sense’, reversing decisions of two lower courts.  It now provides authority against similar prosecutions.  This paper argues that the use of a four-hundred-year-old Shakespearean text in negotiating modern legal principles is of considerable cultural significance – both through using the familiar to respond to the new – and by invoking Shakespeare’s voice within the powerful social mechanism of the law courts.  It also considers the advantages and disadvantages of literary allusions within legal proceedings, contrasting these two widely reported judgments.This piece is adapted from a transcript of: King Lear, Twitter and the Da Vinci Code given as part of the Sidelights on Shakespeare lecture series at University of Warwick on 29 November 2013.Professor Gary Watt provides a response to Curtis's critical reflection, considering judicial allusion as logic or ornament. Image: Cordelia in the Court of King Lear, Sir John Gilbert (1873

  12. en el sector de autopartes en México. El caso de la red de plantas de Lear Corporation

    Directory of Open Access Journals (Sweden)

    Arturo A. Lara Rivero

    2005-01-01

    Full Text Available El propósito de este artículo es describir y analizar el caso de un proveedor de la industria automotriz que, de ser especialista en la producción de asientos, ha evolucionado hasta convertirse en una empresa capaz de suministrar la totalidad del sistema de interiores. El estudio está centrado en la red de plantas de producción que Lear Corporation tiene en México. Se busca examinar el desempeño tecnológico, así como la estrategia de coordinación y cooperación intraempresa (dentro del mercado de América del Norte desarrolladas por Lear en el marco de la producción modular.

  13. Ion optics and beam dynamics optimization at the HESR storage ring for the SPARC experiments with highly charged heavy ions

    OpenAIRE

    Kovalenko, Oleksandr

    2015-01-01

    The High-Energy Storage Ring (HESR) is a part of an upcoming International Facility for Antiproton and Ion Research (FAIR) at GSI in Darmstadt [1]. A key part of a scientific program, along with antiproton physics, will be physics with highly-charged heavy ions. Phase-space cooled beams together with fixed internal target will provide an excellent environment for storage ring experiments at the HESR for the SPARC collaboration [2–4]. Until recently, however, the existing ion optical lattic...

  14. X-ray transitions from antiprotonic noble gases

    International Nuclear Information System (INIS)

    The onset of antiprotonic X-ray transitions at high principal quantum numbers and the occurrence of electronic X-ray in antiprotonic argon krypton, and xenon is analysed with Multiconfiguration Dirac-Fock calculations. The shell by shell ionisation by Auger electron emission, characterised by appearance and disappearance of X-ray lines, is followed through the antiprotonic cascade by considering transition and binding energies of both the antiproton and remaining electrons. A number of additional lines in the X-ray spectra have been tentatively assigned to electronic transitions caused by electronic de-excitation after Auger emission during the antiprotonic cascade. A few lines remain unexplained so far or are not unambiguously assigned. The complexity of the electronic states cannot be resolved with semiconductor detectors. Hopefully, in future high resolution devices like crystal spectrometers and Auger electron spectroscopy at antiproton at GSI will resolve this complexity

  15. The cosmic ray antiproton background for AMS-02

    International Nuclear Information System (INIS)

    The AMS-02 experiment is measuring the cosmic ray antiproton flux with high precision. The interpretation of the upcoming data requires a thorough understanding of the secondary antiproton background. In this work, we employ newly available data of the NA49 experiment at CERN, in order to recalculate the antiproton source term arising from cosmic ray spallations on the interstellar matter. We systematically account for the production of antiprotons via hyperon decay and discuss the possible impact of isospin effects on antineutron production. A detailed comparison of our calculation with the existing literature as well as with Monte Carlo based evaluations of the antiproton source term is provided. Our most important result is an updated prediction for the secondary antiproton flux which includes a realistic assessment of the particle physics uncertainties at all energies

  16. The discovery of geomagnetically trapped cosmic ray antiprotons

    CERN Document Server

    Adriani, O; Bazilevskaya, G A; Bellotti, R; Boezio, M; Bogomolov, E A; Bongi, M; Bonvicini, V; Borisov, S; Bottai, S; Bruno, A; Cafagna, F; Campana, D; Carbone, R; Carlson, P; Casolino, M; Castellini, G; Consiglio, L; De Pascale, M P; De Santis, C; De Simone, N; Di Felice, V; Galper, A M; Gillard, W; Grishantseva, L; Jerse, G; Karelin, A V; Kheymits, M D; Koldashov, S V; Krutkov, S Y; Kvashnin, A N; Leonov, A; Malakhov, V; Marcelli, L; Mayorov, A G; Menn, W; Mikhailov, V V; Mocchiutti, E; Monaco, A; Mori, N; Nikonov, N; Osteria, G; Palma, F; Papini, P; Pearce, M; Picozza, P; Pizzolotto, C; Ricci, M; Ricciarini, S B; Rossetto, L; Sarkar, R; Simon, M; Sparvoli, R; Spillantini, P; Stozhkov, Y I; Vacchi, A; Vannuccini, E; Vasilyev, G; Voronov, S A; Yurkin, Y T; Wu, J; Zampa, G; Zampa, N; Zverev, V G; 10.1088/2041-8205/736/1/L1

    2011-01-01

    The existence of a significant flux of antiprotons confined to Earth's magnetosphere has been considered in several theoretical works. These antiparticles are produced in nuclear interactions of energetic cosmic rays with the terrestrial atmosphere and accumulate in the geomagnetic field at altitudes of several hundred kilometers. A contribution from the decay of albedo antineutrons has been hypothesized in analogy to proton production by neutron decay, which constitutes the main source of trapped protons at energies above some tens of MeV. This Letter reports the discovery of an antiproton radiation belt around the Earth. The trapped antiproton energy spectrum in the South Atlantic Anomaly (SAA) region has been measured by the PAMELA experiment for the kinetic energy range 60--750 MeV. A measurement of the atmospheric sub-cutoff antiproton spectrum outside the radiation belts is also reported. PAMELA data show that the magnetospheric antiproton flux in the SAA exceeds the cosmic-ray antiproton flux by three ...

  17. Physics at CERN’s Antiproton Decelerator

    Science.gov (United States)

    Hori, M.; Walz, J.

    2013-09-01

    The Antiproton Decelerator (AD) facility of CERN began operation in 1999 to serve experiments for studies of CPT invariance by precision laser and microwave spectroscopy of antihydrogen (Hbar ) and antiprotonic helium (pbar He) atoms. The first 12 years of AD operation saw cold Hbar synthesized by overlapping clouds of positrons (e+) and antiprotons (pbar ) confined in magnetic Penning traps. Cold Hbar was also produced in collisions between Rydberg positronium (Ps) atoms and pbar . Ground-state Hbar was later trapped for up to ˜1000 s in a magnetic bottle trap, and microwave transitions excited between its hyperfine levels. In the pbar He atom, deep ultraviolet transitions were measured to a fractional precision of (2.3-5)×10-9 by sub-Doppler two-photon laser spectroscopy. From this the antiproton-to-electron mass ratio was determined as M/me=1836.1526736(23), which agrees with the p value known to a similar precision. Microwave spectroscopy of pbar He yielded a measurement of the pbar magnetic moment with a precision of 0.3%. More recently, the magnetic moment of a single pbar confined in a Penning trap was measured with a higher precision, as μ=-2.792845(12)μ in nuclear magnetons. Other results reviewed here include the first measurements of the energy loss (-dE/dx) of 1-100 keV pbar traversing conductor and insulator targets; the cross sections of low-energy (therapy. New experiments under preparation attempt to measure the gravitational acceleration of Hbar or synthesize H. Several other future experiments will also be briefly described.

  18. Magnetic horn of the Antiproton Accumulator (AA)

    CERN Multimedia

    Photographic Service

    1988-01-01

    In the 1960s, the invention of this "current sheet lens" has helped to greatly improve the flux of neutrino beams. It was used again at the AA, collecting antiprotons from the production target at angles too large to fit into the acceptance of the AA. It was machined from aluminium to a thickness of 1.4 mm and pulsed at 400 kA for 15 microseconds (half-sine).

  19. Shielding calculations for the antiproton target area

    International Nuclear Information System (INIS)

    Shielding calculations performed in conjunction with the design of the Fermilab antiproton target hall are summarized. The following radiological considerations were examined: soil activation, residual activity of components, and beam-on radiation. In addition, at the request of the designers, the energy deposition in the proposed graphite beam dump was examined for several targeting conditions in order to qualitatively determine its ability to survive

  20. Measurements of Cosmic Ray Antiprotons with PAMELA

    OpenAIRE

    Wu, Juan

    2010-01-01

    The PAMELA experiment is a satellite-borne apparatus designed to study charged particles, and especially antiparticles, in the cosmic radiation. The apparatus is mounted on the Resurs DK1 satellite which was launched on 15 June 2006. PAMELA has been traveling around the earth along an elliptical and semi-polar orbit for almost five years. It mainly consists of a permanent magnetic spectrometer, a time of flight system and an electromagnetic imaging calorimeter, which allows antiprotons to be ...

  1. Looking for new gravitational forces with antiprotons

    International Nuclear Information System (INIS)

    Quite general arguments based on the principle of equivalence and modern field theory show that it is possible for the gravitational acceleration of antimatter to be different than that for matter. Further, there is no experimental evidence to rule out the possibility. In fact, some evidence indicates there may be unexpected effects. Thus, the planned experiment to measure the gravitational acceleration of antiprotons is of fundamental importance. 20 refs., 3 figs

  2. Kaons and antiproton-nucleus scattering

    International Nuclear Information System (INIS)

    The elastic scattering of Kaons and antiprotons from several nuclei is studied in the framework of the generalized diffraction model due to Frahn and Venter. The systematics of reaction cross section and the standard nuclear radius, as given by the model, are discussed. The parameters obtained from the elastic scattering analyses are used, without any adjustment, to reproduce some inelastic scattering angular distributions and the corresponding deformation parameters are determined. (author)

  3. A new approach to experiments with non-relativistic antiprotons

    International Nuclear Information System (INIS)

    Is low-energy antiproton physics phasing out with the present round of experiments or are there good reasons to continue at an improved slow antiproton facility which could be located at a high intensity hadron accelerator? We point out, that there are four frontiers where substantial advances could be made. In particular, we discuss the low-energy frontier and emphasize that experiments with no-relativistic antiprotons would increase drastically the sensitivity and would reveal new effects. (orig.)

  4. Antiproton production in relativistic Si-nucleus collisions

    International Nuclear Information System (INIS)

    We have measured antiproton production cross sections as functions of centrality in collisions of 14.6 GeV/c per nucleon 28Si ions with targets of Al, Cu, and Pb. For all targets, the antiproton yields increase linearly with the number of projectile nucleons that have interacted, and show little target dependence. We discuss the implications of this result on the production and absorption of antiprotons within the nuclear medium

  5. The FLUKA study of the secondary particles fluence in the AD-Antiproton Decelerator target area

    CERN Document Server

    Calviani, M

    2014-01-01

    In this paper we present Monte Carlo FLUKA simulations [1, 2] carried out to investigate the secondary particles fluence emerging from the antiproton production target and their spatial distribution in the AD target area. The detailed quantitative analysis has been performed for different positions along the magnet dog-leg as well as after the main collimator. These results allow tuning the position of the new beam current transformers (BCT) in the target area, in order to have a precise pulse-by-pulse evaluation of the intensity of negative particles injected in the AD-ring before the deceleration phase.

  6. ELENA prepares a bright future for antimatter research

    CERN Multimedia

    CERN Bulletin

    2011-01-01

    At its recent session in June, the CERN Council approved the construction of the Extra Low ENergy Antiproton ring (ELENA) – an upgrade of the existing Antiproton Decelerator. ELENA will allow the further deceleration of antiprotons, resulting in an increased number of particles trapped downstream in the experimental set-ups. This will give an important boost to antimatter research in the years to come.   Layout of the AD experimental hall: the Antiproton Decelerator ring (purple); the ALPHA, ASACUSA, and ATRAP experiments (green); the ACE experiment (not pictured); and the new ELENA ring (blue). The Antiproton Decelerator (AD) is CERN’s widely recognized facility for the study of antimatter properties. The recent successes of the AD experiments are just the latest in a long list of important scientific results that started with LEAR (Low Energy Antiproton Ring). The scientific demand for low-energy antiprotons at the AD continues to grow. There are now four experiments runnin...

  7. Ring Theory

    CERN Document Server

    Jara, Pascual; Torrecillas, Blas

    1988-01-01

    The papers in this proceedings volume are selected research papers in different areas of ring theory, including graded rings, differential operator rings, K-theory of noetherian rings, torsion theory, regular rings, cohomology of algebras, local cohomology of noncommutative rings. The book will be important for mathematicians active in research in ring theory.

  8. Serach for polarization effects in the antiproton production process

    CERN Multimedia

    It is proposed to study polarization effects in the production of antiprotons at the PS test beam line T11 at 3.5 GeV/c momentum. A polarization in the production process has never been studied but if existing it would allow for a rather simple and cheap way to generate a polarized antiproton beam with the existing facilities at CERN.

  9. A study of the reactions antiproton-d→antiproton-dπ+π- and antiproton-d→psub(s)antiproton-pπ- at 14.6 GeV/c and a study of charged multiplicity distributions

    International Nuclear Information System (INIS)

    An analysis of two reactions on deuterium has been performed with incident antiprotons of 14.6 GeV/c: antiproton-d→antiproton-dπ+π- and antiproton-d→psub(s)antiproton-pπ-. The final states are dominated by Δ(1236) resonance production and in the coherent reaction the d* effect is observed as at lower incident momenta. At 14.6 GeV/c, it seems that the diffraction dissociation process as well for the incident particle as for the target takes a large part of the production mechanism for the two reactions. A study of charged multiplicity distributions in antiproton-neutron interactions is presented at 5.5, 9.3 and 14.6 GeV/c. The topological cross sections as well as various statistical moments obtained from the charged multiplicities are studied as functions of the incident momentum. A comparison between our results and antiproton-proton and pp data shows, that in the range of incident momenta used, a scaling function which describes antiproton-N and proton-proton interactions does not exist as expected from the KNO model (Koba-Nielsen-Olesen model)

  10. Antiproton impact ionization of atomic hydrogen and helium

    Energy Technology Data Exchange (ETDEWEB)

    McGovern, M; Walters, H R J [Department of Applied Mathematics and Theoretical Physics, Queen' s University, Belfast BT7 INN (United Kingdom); Assafrao, D; Mohallem, J R [Laboratorio de Atomos e Moleculas Especiais, Departamento de Fisica, ICEx, Universidade Federal de Minas Gerais, P.O Box 702, 30123-970 Belo Horizonte, MG (Brazil); Whelan, Colm T, E-mail: mmcgovern06@qub.ac.u [Department of Physics, Old Dominion University, Norfolk, VA 23529-0116 (United States)

    2009-11-01

    We shall present results for antiproton ionization of H and He ranging from fully differential cross sections to total ionization. The calculations have been made in a coupled pseudostate impact parameter approximation. It will be shown that the interaction between the antiproton and the target nucleus is very important at low energies.

  11. Intensity-Frontier Antiproton Physics with The Antiproton Annihilation Spectrometer (TAPAS) at Fermilab

    Energy Technology Data Exchange (ETDEWEB)

    Apollinari, Giorgio; /Fermilab; Asner, David M.; /PNL, Richland; Baldini, Wander; /INFN, Ferrara; Bartoszek, Larry; Broemmelsiek, Daniel R.; Brown, Charles N.; /Fermilab; Chakravorty, Alak; /St. Xavier U., Chicago; Colas, Paul; /Saclay; Derwent, Paul; /Fermilab; Drutskoy, Alexey; /Moscow, ITEP; Fortner, Michael; /Northern Illinois U. /Saclay /Indian Inst. Tech., Hyderabad

    2011-11-01

    The Fermilab Antiproton Source is the world's most intense source of antimatter. With the Tevatron program now behind us, this unique facility can help make the case for Fermilab's continued accelerator operations. The Antiproton Source can be used for unique, dedicated antimatter studies, including medium-energy {bar p}-annihilation experiments. We propose to assemble a powerful, yet cost-effective, solenoidal magnetic spectrometer for antiproton-annihilation events, and to use it at the Fermilab Antiproton Accumulator to measure the charm production cross section, study rare hyperon decays, search for hyperon CP asymmetry, precisely measure the properties of several charmonium and nearby states, and make the first measurements of the Drell-Yan continuum in medium-energy antiproton annihilation. Should the charm production cross section be as large as some have proposed, we will also be able to measure D{sup 0}-{bar D}{sup 0} mixing with high precision and discover (or sensitively limit) charm CP violation. The observation of charm or hyperon CP violation would be evidence for physics beyond the Standard Model, with possible implications for the origin of the baryon asymmetry of the universe - the question of what happened to all the antimatter that must have been produced in the Big Bang. The experiment will be carried out by an international collaboration and will require some four years of running time. As possibly the sole hadron experiment in progress at Fermilab during that time, it will play an important role in maintaining a broad particle physics program at Fermilab and in the U.S. It will thus help us to continue attracting creative and capable young people into science and technology, and introducing them to the important technologies of accelerators, detectors, and data acquisition and analysis - key roles in society that accelerator-based particle physics has historically played.

  12. An Update on the Depth-Dose Curve of Antiprotons

    DEFF Research Database (Denmark)

    Taasti, Vicki Trier; Holzscheiter, Michael H.; Knudsen, Helge;

    Purpose: The CERN AD-4/ACE project aims to measure the relative biological effectiveness of antiprotons. We have revisited previously published data for the antiproton depth-dose curve [1], where the relative dose deposition normalized to a point in the plateau region was plotted. In this revision...... we refine the experimental set-up to obtain absolute dose per primary particle, and compare these with simulations. Materials and Methods: Scrutinizing the geometrical setup, we could calculate beam scattering along the antiproton beam, which enables replotting the depth-dose curve as absolute dose...... is annihilating on. Precise modelling of the detector is therefore inevitable. The missing energy in the annihilation peak remains to be explained, but may be related to an overestimation of inelastic cross sections of the antiprotons. [1] Bassler, N., et al., The antiproton depth-dose curve in water, Phys. Med...

  13. Detailed analysis of observed antiprotons in cosmic rays

    Directory of Open Access Journals (Sweden)

    P Davoudifar

    2009-12-01

    Full Text Available In the present work, the origin of antiprotons observed in cosmic rays (above the atmosphere is analyzed in details. We have considered the origin of the primaries, (which their interactions with the interstellar medium is one of the most important sources of antiprotons is a supernova type II then used a diffusion model for their propagation. We have used the latest parameterization for antiproton production cross section in pp collisions (instead of well known parameterization introduced by Tan et al. as well as our calculated residence time for primaries. The resulted intensity shows the secondary antiprotons produced in pp collisions in the galaxy, have a high population as one can not consider an excess for extragalactic antiprotons. Also there is a high degree of uncertainty in different parameters.

  14. Antiproton cloud compression in the ALPHA apparatus at CERN

    Energy Technology Data Exchange (ETDEWEB)

    Gutierrez, A., E-mail: andrea.gutierrez@triumf.ca [University of British Columbia, Department of Physics and Astronomy (Canada); Ashkezari, M. D. [Simon Fraser University, Department of Physics (Canada); Baquero-Ruiz, M. [University of California at Berkeley, Department of Physics (United States); Bertsche, W. [University of Manchester, School of Physics and Astronomy (United Kingdom); Burrows, C. [Swansea University, Department of Physics, College of Science (United Kingdom); Butler, E. [Centre for Cold Matter, Imperial College (United Kingdom); Capra, A. [York University, Department of Physics and Astronomy (Canada); Cesar, C. L. [Universidade Federal do Rio de Janeiro, Instituto de Física (Brazil); Charlton, M. [Swansea University, Department of Physics, College of Science (United Kingdom); Dunlop, R. [Simon Fraser University, Department of Physics (Canada); Eriksson, S. [Swansea University, Department of Physics, College of Science (United Kingdom); Evetts, N. [University of British Columbia, Department of Physics and Astronomy (Canada); Fajans, J. [University of California at Berkeley, Department of Physics (United States); Friesen, T. [Aarhus University, Department of Physics and Astronomy (Denmark); Fujiwara, M. C.; Gill, D. R. [TRIUMF (Canada); Hangst, J. S. [Aarhus University, Department of Physics and Astronomy (Denmark); Hardy, W. N. [University of British Columbia, Department of Physics and Astronomy (Canada); Hayden, M. E. [Simon Fraser University, Department of Physics (Canada); Isaac, C. A. [Swansea University, Department of Physics, College of Science (United Kingdom); and others

    2015-11-15

    We have observed a new mechanism for compression of a non-neutral plasma, where antiprotons embedded in an electron plasma are compressed by a rotating wall drive at a frequency close to the sum of the axial bounce and rotation frequencies. The radius of the antiproton cloud is reduced by up to a factor of 20 and the smallest radius measured is ∼ 0.2 mm. When the rotating wall drive is applied to either a pure electron or pure antiproton plasma, no compression is observed in the frequency range of interest. The frequency range over which compression is evident is compared to the sum of the antiproton bounce frequency and the system’s rotation frequency. It is suggested that bounce resonant transport is a likely explanation for the compression of antiproton clouds in this regime.

  15. Antiproton cloud compression in the ALPHA apparatus at CERN

    International Nuclear Information System (INIS)

    We have observed a new mechanism for compression of a non-neutral plasma, where antiprotons embedded in an electron plasma are compressed by a rotating wall drive at a frequency close to the sum of the axial bounce and rotation frequencies. The radius of the antiproton cloud is reduced by up to a factor of 20 and the smallest radius measured is ∼ 0.2 mm. When the rotating wall drive is applied to either a pure electron or pure antiproton plasma, no compression is observed in the frequency range of interest. The frequency range over which compression is evident is compared to the sum of the antiproton bounce frequency and the system’s rotation frequency. It is suggested that bounce resonant transport is a likely explanation for the compression of antiproton clouds in this regime

  16. Antiproton-neon annihilation at 57 MeV/c

    CERN Document Server

    Bianconi, A; Bussa, M P; Lodi-Rizzini, E; Venturelli, L; Zenoni, A; Pontecorvo, G B; Guaraldo, C; Balestra, F; Busso, L; Colantoni, M L; Ferrero, A; Ferrero, L; Grasso, A; Maggiora, A; Maggiora, M G; Piragino, G; Tosello, F

    2000-01-01

    The pNe annihilation cross section is measured for the first time in the momentum interval (53/63) MeV/c. About 9000 pictures collected by the Streamer Chamber Collaboration (PS179) at LEAR-CERN have been scanned. Four events are found, corresponding to sigma /sub ann /=2210+or-1105 mb. The result is compared to the set of measurements presently available in the region of low p momentum. (18 refs).

  17. Calculated LET Spectrum from Antiproton Beams Stopping in Water

    DEFF Research Database (Denmark)

    Bassler, Niels; Holzscheiter, Michael

    2009-01-01

    Antiprotons have been proposed as a potential modality for radiotherapy because the annihilation at the end of range leads to roughly a doubling of physical dose in the Bragg peak region. So far it has been anticipated that the radiobiology of antiproton beams is similar to that of protons...... significantly differ from unity, which seems to warrant closer inspection of the radiobiology in this region. Monte Carlo simulations using FLUKA were performed for calculating the entire particle spectrum of a beam of 126 MeV antiprotons hitting a water phantom. In the plateau region of the simulated...

  18. Prospects for antiproton physics, my perspective

    Energy Technology Data Exchange (ETDEWEB)

    Oelert, Walter, E-mail: w.oelert@fz-juelich.de [Forschungszentrum Juelich (Germany)

    2012-12-15

    These closing remarks are not supposed to be a summary talk, for this please have a look to the individual contributions to be published in the proceedings, but rather some considerations on future prospects for antiproton physics. However, first I would like to appreciate the organizers idea for giving me the opportunity to thank them for a well balanced, exciting and interesting conference LEAP-2011 in this marvelous city of Vancouver. I am sure we all loved to be here and enjoyed the hospitality and the bond of friendship we could experience during these days. We appreciate the patience and help of all the local organizers where I especially would like to mention Jana Thomson for her endless and helpful assignment. Thank you all-the participants, the speakers, the conference chair, the sponsors-for making this conference a success and we are looking forward to the next occasion in this series of meetings which will be celebrated in Uppsala.

  19. Antiproton cell experiment: antimatter is a better killer

    CERN Multimedia

    2006-01-01

    "European Organization for Nuclear Research is reporting that results from a three year study of antiprotons for neoplasm irrdiation showed a better cellular killer with a smaller lethal dose." (1,5 page)

  20. Antiprotons from dark matter annihilation in the Galaxy: astrophysical uncertainties

    CERN Document Server

    Evoli, Carmelo; Grasso, Dario; Maccione, Luca; Ullio, Piero

    2011-01-01

    The latest years have seen steady progresses in WIMP dark matter (DM) searches, with hints of possible signals suggested by both direct and indirect detection experiments. Antiprotons can play a key role validating those interpretations since they are copiously produced by WIMP annihilations in the Galactic halo, and the secondary antiproton background produced by Cosmic Ray (CR) interactions is predicted with fair accuracy and matches the observed spectrum very well. Using the publicly available numerical DRAGON code, we reconsider antiprotons as a tool to constrain DM models discussing its power and limitations. We provide updated constraints on a wide class of annihilating DM models by comparing our predictions against the most up-to-date ap measurements, taking also into account the latest spectral information on the p, He and other CR nuclei fluxes. Doing that, we probe carefully the uncertainties associated to both secondary and DM originated antiprotons, by using a variety of distinctively different as...

  1. Do positrons and antiprotons respect the weak equivalence principle?

    International Nuclear Information System (INIS)

    We resolve the difficulties which Morrison identified with energy conservation and the gravitational red-shift when particles of antimatter, such as the positron and antiproton, do not respect the weak equivalence principle. 13 refs

  2. Cosmic Antiproton Constraints on Effective Interactions of the Dark Matter

    CERN Document Server

    Cheung, Kingman; Yuan, Tzu-Chiang

    2010-01-01

    Using an effective interaction approach to describe the interactions between the dark matter particle and the light degrees of freedom of the standard model, we calculate the antiproton flux due to the annihilation of the dark matter in the Galactic Halo and compare to the most recent antiproton spectrum of the PAMELA experiment. We obtain useful constraints on the size of the effective interactions that are comparable to those deduced from collider and gamma-ray experiments.

  3. Cosmic antiproton constraints on effective interactions of the dark matter

    Energy Technology Data Exchange (ETDEWEB)

    Cheung, Kingman [Division of Quantum Phases and Devices, School of Physics, Konkuk university, Seoul 143-701 (Korea, Republic of); Tseng, Po-Yan [Department of Physics, National Tsing Hua University, Hsinchu 300, Taiwan (China); Yuan, Tzu-Chiang, E-mail: cheung@phys.nthu.edu.tw, E-mail: tcyuan@phys.sinica.edu.tw, E-mail: d9722809@oz.nthu.edu.tw [Institute of Physics, Academia Sinica, Nankang, Taipei 11529, Taiwan (China)

    2011-01-01

    Using an effective interaction approach to describe the interactions between the dark matter particle and the light degrees of freedom of the standard model, we calculate the antiproton flux due to the annihilation of the dark matter in the Galactic Halo and compare to the most recent antiproton spectrum of the PAMELA experiment. We obtain useful constraints on the size of the effective interactions that are comparable to those deduced from collider and gamma-ray experiments.

  4. Cosmic antiproton constraints on effective interactions of the dark matter

    International Nuclear Information System (INIS)

    Using an effective interaction approach to describe the interactions between the dark matter particle and the light degrees of freedom of the standard model, we calculate the antiproton flux due to the annihilation of the dark matter in the Galactic Halo and compare to the most recent antiproton spectrum of the PAMELA experiment. We obtain useful constraints on the size of the effective interactions that are comparable to those deduced from collider and gamma-ray experiments

  5. Low-energy collisions of antiprotons with atoms and molecules

    International Nuclear Information System (INIS)

    Time-dependent close-coupling calculations were performed using the impact parameter method for antiproton and proton collisions with alkali-metal atoms and hydrogen molecules. The targets are described as effective one-electron systems using appropriate model potentials. The proton data verify the employed method while the results for antiprotons improve the literature on these systems considerably. Cross sections for ionization and excitation as well as electron-energy spectra and stopping power will be presented.

  6. The race to create

    International Nuclear Information System (INIS)

    Physicists of CERN are seeking to produce antiatoms of hydrogen using the already available sources of positrons and antiprotons from the Low Energy Antiproton Ring (LEAR). In these experiments the antihydrogen will be immediately destroyed, but physicists plan to capture and store it in future for more systematic experiments. Future work will aim to test the reliability of cornerstones of High Energy Physics theory, such as the Standard Model, and CPT symmetry and quantum electrodynamics. Hydrogen and antihydrogen would be subjected to matching variations of gravitational fields and changes in particular spectral lines would be assessed. The future of these experiments depends on LEAR funding which is currently under review. (U.K.)

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

    CERN Document Server

    Fernandes, M; Soby, L; Welsch, CP

    2013-01-01

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

  8. Antiproton-impact ionization of H2

    International Nuclear Information System (INIS)

    Ionization processes in antiproton collisions with H2 are studied by direct solution of the time-dependent Schroedinger equation. A time-dependent close-coupling method based on an expansion of a one-electron 3D wavefunction in the field of H+2 is used to calculate single-ionization cross sections at incident energies ranging from 50 keV to 1.5 MeV. Averaging over the molecular orientations, the single-ionization cross sections are in reasonable agreement with time-dependent basis set calculations and experiment. A time-dependent close-coupling method based on an expansion of a two-electron 6D wavefunction in the field of H2+2 is used to calculate single- and double-ionization cross sections at an incident energy of 100 keV. Initiatory 6D results for the H+2 production cross section range are somewhat lower than experiment, while the H+ production cross section range brackets experiment.

  9. Calculated LET spectrum from antiproton beams stopping in water

    CERN Document Server

    Bassler, Niels

    2009-01-01

    Antiprotons have been proposed as a potential modality for radiotherapy because the annihilation at the end of range leads to roughly a doubling of physical dose in the Bragg peak region. So far it has been anticipated that the radiobiology of antiproton beams is similar to that of protons in the entry region of the beam, but very different in the annihilation region, due to the expected high-LET components resulting from the annihilation. On closer inspection we find that calculations of dose averaged LET in the entry region may suggest that the RBE of antiprotons in the plateau region could significantly differ from unity, which seems to warrant closer inspection of the radiobiology in this region. Materials and Methods. Monte Carlo simulations using FLUKA were performed for calculating the entire particle spectrum of a beam of 126 MeV antiprotons hitting a water phantom. Results and Discussion. In the plateau region of the simulated antiproton beam we observe a dose-averaged unrestrict...

  10. A low-energy antiproton detector prototype for AFIS

    Energy Technology Data Exchange (ETDEWEB)

    Meng, Lingxin; Greenwald, Daniel; Hahn, Alexander; Hauptmann, Philipp; Konorov, Igor; Losekamm, Martin; Paul, Stephan; Poeschl, Thomas; Renker, Dieter [Technische Universitaet Muenchen (Germany)

    2014-07-01

    Antiprotons are produced in interactions of primary cosmic rays with earth's exosphere, where a fraction of them will be confined in the geomagnetic field in the inner van Allen Belt. The antiproton-to-proton flux ratio predicted by theory is in good agreement with recent results from the South Atlantic Anomaly (SAA) published by the PAMELA collaboration. We have designed the AFIS (Antiproton Flux in Space) project in order to extend the measurable range of antiprotons towards the low-energy region. In scope of this project a small antiproton detector consisting of scintillating fibers and silicon photomultipliers is being developed as payload for a CubeSat traversing the SAA in Low Earth Orbit. For the proof of concept we have built a prototype called ''CubeZero'' which completed its first test using pion and proton beams at PSI, Switzerland. Our primary goal was to investigate on the performance of tracking and Bragg peak identification in hardware and software. Analysis of detector performance based on data taken during this beam test is presented in this talk.

  11. The Floor's the Limit (Antiproton energies to hit new low)

    CERN Multimedia

    2000-01-01

    Celebrating the success of the RFQ in Aarhus. Left to right: Alessanda Lombardi (CERN), Iouri Bylinskii (CERN), Alex Csete (Aarhus), Ulrik Uggerhøj (Aarhus), Ryu Hayano (Tokyo, spokesman ASACUSA), Helge Knudsen (Aarhus), Werner Pirkl (CERN), Ryan Thompson (Aarhus), Søren P. Møller (Aarhus). Although in particle physics we are accustomed to strive for higher and higher energies, this is not always the most interesting thing to do with antiprotons. Indeed, as recent issues of the Bulletin have suggested, the signpost on the road to a closer look at the antiproton points towards ever-lower energies. The CERN Antiproton Decelerator decelerates antipro-tons emerging from a target placed in the path of a 26 GeV/c proton beam from 90 % of to about 10 % of the speed of light. However, even this is far too fast for many of the most interesting experiments on antiprotons planned by Danish and Japanese members of the ASACUSA collaboration. Tokyo University has therefore financed the con...

  12. Relative Biological Effect of Antiprotons

    DEFF Research Database (Denmark)

    Bassler, Niels; Holzscheiter, Michael

    purpose/objective The AD-4/ACE collaboration has recently performed experiments to directly measure the RBE of antiprotons. Antiprotons have very similar stopping power compared to protons, but when they come to rest, antiprotons will annihilate on a target nucleus and thereby release almost 2 Ge...

  13. Many Facets of Strangeness Nuclear Physics with Stored Antiprotons

    CERN Document Server

    Pochodzalla, Josef; Lorente, Alicia Sanchez; Rojo, Marta Martinez; Steinen, Marcell; Gerl, Jürgen; Kojouharova, Jasmina; Kojouharova, Ivan

    2016-01-01

    Stored antiprotons beams in the GeV range represent a unparalleled factory for hyperon-antihyperon pairs. Their outstanding large production probability in antiproton collisions will open the floodgates for a series of new studies of strange hadronic systems with unprecedented precision. The behavior of hyperons and -- for the first time -- of antihyperons in nuclear systems can be studied under well controlled conditions. The exclusive production of $\\Lambda\\bar{\\Lambda}$ and $\\Sigma^-\\bar{\\Lambda}$ pairs in antiproton-nucleus interactions probe the neutron and proton distribution in the nuclear periphery and will help to sample the neutron skin. For the first time, high resolution $\\gamma$-spectroscopy of doubly strange nuclei will be performed, thus complementing measurements of ground state decays of double hypernuclei with mesons beams at J-PARC or possible decays of particle unstable hypernuclei in heavy ion reactions. High resolution spectroscopy of multistrange $\\Xi$-atoms are feasible and even the pr...

  14. Antiproton-Nucleus Interaction and Coulomb Effect at High Energies

    Institute of Scientific and Technical Information of China (English)

    ZHOU Li-Juan; WU Qing; GU Yun-Ting; MA Wei-Xing; TAN Zhen-Qiang; HU Zhao-Hui

    2005-01-01

    The Coulomb effect in high energy antiproton-nucleus elastic and inelastic scattering from 12C and 16O is studied in the framework of Glauber multiple scattering theory for five kinetic energies ranged from 0.23 to 1.83 GeV.A microscopic shell-model nuclear wave functions, Woods-Saxon single-particle wave functions, and experimental pN amplitudes are used in the calculations. The results show that the Coulomb effect is of paramount importance for filling up the dips of differential cross sections. We claim that the present result for inelastic scattering of antiproton-12C is sufficiently reliable to be a guide for measurements in the very near future. We also believe that antiproton nucleus elastic and inelastic scattering may produce new information on both the nuclear structure and the antinucleon-nucleon interaction, in particular the p-neutron interaction.

  15. Strangeness production and hypernucleus formation in antiproton induced reactions

    CERN Document Server

    Feng, Zhao-Qing

    2015-01-01

    Formation mechanism of fragments with strangeness in collisions of antiprotons on nuclei has been investigated within the Lanzhou quantum molecular dynamics (LQMD) transport approach combined with a statistical model (GEMINI) for describing the decays of excited fragments. Production of strange particles in the antiproton induced nuclear reactions is modeled within the LQMD model, in which all possible reaction channels such as elastic scattering, annihilation, charge exchange and inelastic scattering in antibaryon-baryon, baryon-baryon and meson-baryon collisions have been included. A coalescence approach is developed for constructing hyperfragments in phase space after de-excitation of nucleonic fragments. The combined approach could describe the production of fragments in low-energy antiproton induced reactions. Hyperfragments are formed within the narrower rapidities and lower kinetic energies. It has advantage to produce heavier hyperfragments and hypernuclides with strangeness s=-2 (double-$\\Lambda$ fra...

  16. Measurement of the Spin–Dependence of the $\\overline{p}-p$ Interaction at the AD–Ring

    CERN Document Server

    Barschel, C; Dietrich, J; Dolfus, N; Engels, R; Gebel, R; Hadamek, H; Haidenbauer, J; Hanhart, C; Kacharava, A; Krol, G; Küven, M; Langenberg, G; Lehrach, A; Lorentz, B; Maier, R; Martin, S; Meissner, U G; Nekipelov, M; Nikolaev, N N; Oellers, D; d'Orsaneo, G; Prasuhn, D; Rathmann, F; Retzlaff, M; Sarkadi, J; Schleichert, R; Seyfarth, H; Sibirtsev, A; Spölgen, D; Stein, H J; Stockhorst, H; Ströher, H; Weidemann, Chr; Welsch, D; Wieder, P; Barion, L; Bertelli, S; Carassiti, V; Ciullo, G; Contalbrigo, M; Cotta-Ramusino, A; Dalpiaz, P F; Drago, A; Guidoboni, G; Lenisa, P; Pappalardo, L; Stancari, G; Stancari, M; Statera, M; Azarian, T; Kulikov, A; Kurbatov, V; Macharashvili, G; Merzliakov, S; Meshkov, I N; Smirnov, A; Tsirkov, D; Uzikov, Yu; Barsov, S; Belostotskii, S; Grigoryev, K; Kravtsov, P; Mikirtychiants, M; Mikirtychiants, S; Vasilyev, A; Esser, F M; Greven, R; Hansen, G; Jadgfeld, F; Klehr, F; Soltner, H; Straatmann, H; Chiladze, D; Garishvili, A; Lomidze, N; Mchedlishvili, D; Nioradze, M; Tabidze, M; Akopov, N; Avetisyan, A; Elbakyan, G; Marukyan, H; Taroian, S; Benati, P; Erven, W; Kayser, F J; Kleines, H; Wüstner, P; Bruncko, D; Ferencei, J; Musinsky, J; Urbán, J; Augustyniak, W; Marianski, B; Trzcinski, A; Zupranski, P; Dymov, S; Nass, A; Steffens, E; Rathsman, K; Tegnér, P E; Engblom, P Thoerngren; De Leo, R; Tagliente, G; Kämpfer, B; Trusov, S; Buttimore, N; Meyer, H O; CERN. Geneva. SPS and PS Experiments Committee; SPSC

    2009-01-01

    We propose to use an internal polarized hydrogen storage cell gas target in the AD ring to determine for the first time the two total spin–dependent pbar-p cross sections σ1 and σ2 at antiproton beam energies in the range from 50 to 450 MeV. The data obtained are of interest by themselves for the general theory of pbar-p interactions since they will provide a first experimental constraint of the spin–spin dependence of the nucleon–antinucleon potential in the energy range of interest. In addition, measurements of the polarization buildup of stored antiprotons are required to define the optimum parameters of a future, dedicated Antiproton Polarizer Ring (APR), intended to feed a double–polarized asymmetric pbar-p collider with polarized antiprotons. Such a machine has recently been proposed by the PAX collaboration for the new Facility for Antiproton and Ion Research (FAIR) at GSI in Darmstadt, Germany. The availability of an intense stored beam of polarized antiprotons will provide access to a wealt...

  17. Hamlet, Macbeth, Othello and King Lear in the English Teaching at School: a methodological approach - doi: 10.4025/actascieduc.v34i2.15070

    Directory of Open Access Journals (Sweden)

    Valdomiro Polidório

    2012-11-01

    Full Text Available In this article we will talk about the relevance of dramatic texts in schools. Therefore we will approach the tragedies Hamlet, Macbeth, Otelo e King Lear de William Shakespeare and how teachers can explore them as a help in the teaching of languages without forgetting that they are dramatic and literary texts. When we refer to languages, we want to say any language, because Shakespearean texts are ageless, may have many meanings and deal with human nature. The theatre is in our lives and in this case it is relevant to quote William Shakespeare himself that said that “life is a stage and we are actors”. Starting from this, we will consider the best ways of using the tragedies Hamlet, Macbeth, Otelo e King Lear in the classroom.  

  18. High-energy antiprotons from old supernova remnants

    CERN Document Server

    Blasi, Pasquale

    2009-01-01

    A recently proposed model (arXiv:0903.2794) explains the rise in energy of the positron fraction measured by the PAMELA satellite in terms of hadronic production of positrons in aged supernova remnants, and acceleration therein. Here we present a preliminary calculation of the anti-proton flux produced by the same mechanism. While the model is consistent with present data, a rise of the antiproton to proton ratio is predicted at high energy, which strikingly distinguishes this scenario from other astrophysical explanations of the positron fraction (like pulsars). We briefly discuss important implications for Dark Matter searches via antimatter.

  19. Effect of the sextupole distribution on the momentum aperture in the small cooling ring lattice at Fermilab

    Energy Technology Data Exchange (ETDEWEB)

    Month, M.; Wiedemann, H.

    1978-01-01

    In the process of cooling and accumulating antiprotons for use in p-anti p collisions, rings must be designed with a large usable momentum aperture, on the order of 3% or larger. Since long straight sections and dispersionless regions are generally required, the sextupole field correction system for ''chromatic aberration'' is an important aspect of the overall lattice design. The Fermilab small cooling ring, whose purpose is to demonstrate the feasibility of cooling and accumulating protons (and antiprotons) with electrons, is a particularly simple system. This lattice is used to show the sensitivity of the momentum aperture to the sextupole correction system distribution.

  20. Measurement of 0.25-3.2 GeV antiprotons in the cosmic radiation

    DEFF Research Database (Denmark)

    Mitchell, J.W.; Barbier, L.M.; Christian, E.R.;

    1996-01-01

    The balloon-borne Isotope Matter-Antimatter Experiment (IMAX) was flown from Lynn Lake, Manitoba, Canada on 16-17 July 1992. Using velocity and magnetic rigidity to determine mass, we have directly measured the abundances of cosmic ray antiprotons and protons in the energy range from 0.25 to 3.2 Ge......V. Both the absolute flux of antiprotons and the antiproton/proton ratio are consistent with recent theoretical work in which antiprotons are produced as secondary products of cosmic ray interactions with the interstellar medium. This consistency implies a lower limit to the antiproton lifetime of similar...

  1. Ring theory

    CERN Document Server

    Rowen, Louis H

    1991-01-01

    This is an abridged edition of the author's previous two-volume work, Ring Theory, which concentrates on essential material for a general ring theory course while ommitting much of the material intended for ring theory specialists. It has been praised by reviewers:**""As a textbook for graduate students, Ring Theory joins the best....The experts will find several attractive and pleasant features in Ring Theory. The most noteworthy is the inclusion, usually in supplements and appendices, of many useful constructions which are hard to locate outside of the original sources....The audience of non

  2. Measurement of cosmic-ray antiproton spectrum at solar minimum with a long-duration balloon flight in Antarctica

    CERN Document Server

    Abe, K; Haino, S; Hams, T; Hasegawa, M; Horikoshi, A; Kim, K C; Kusumoto, A; Lee, M H; Makida, Y; Matsuda, S; Matsukawa, Y; Mitchell, J W; Nishimura, J; Nozaki, M; Orito, R; Ormes, J F; Sakai, K; Sasaki, M; Seo, E S; Shinoda, R; Streitmatter, R E; Suzuki, J; Tanaka, K; Thakur, N; Yamagami, T; Yamamoto, A; Yoshida, T; Yoshimura, K

    2011-01-01

    The energy spectrum of cosmic-ray antiprotons has been measured in the range 0.17 to 3.5 GeV, based on 7886 antiprotons collected by the BESS-Polar II instrument during a long-duration flight over Antarctica in the solar minimum period of December 2007 through January 2008. The antiproton spectrum measured by BESS-Polar II shows good consistency with secondary antiproton calculations. Cosmologically primary antiprotons have been searched for by comparing the observed and calculated antiproton spectra. The BESS-Polar II result shows no evidence of primary antiprotons originating from the evaporation of PBH.

  3. Beam Diagnostics for Measurements of Antiproton Annihilation Cross Sections at Ultra-low Energy

    Directory of Open Access Journals (Sweden)

    Todoroki K.

    2014-03-01

    Full Text Available The ASACUSA (Atomic Spectroscopy And Collisions Using Slow Antiprotons collaboration of CERN is currently attempting to measure the antiproton-nucleus in-flight annihilation cross sections on thin target foils of C, Pd, and Pt at 130 keV of kinetic energy. The low-energy antiprotons were supplied by the Antiproton Decelerator (AD and a radio-frequency quadrupole decelerator. For this measurement, a beam profile monitor based on secondary electron emission was developed. Data from this monitor was used to ensure that antiprotons were precisely tuned to the position of an 80-mm-diameter experimental target, by measuring the spatial profile of 200-ns-long beam pulses containing 105 − 106 antiprotons with an active area of 40 mm × 40 mm and a spatial resolution of 4 mm. By using this monitor, we succeeded in finely tuning antiproton beams on the target, and observed some annihilation events originating from the target.

  4. Secondary antiprotons as a Galactic Dark Matter probe

    CERN Document Server

    Evoli, Carmelo; Grasso, Dario

    2015-01-01

    We present a novel determination of the astrophysical uncertainties associated to the secondary antiproton flux originating from cosmic-ray spallation on the interstellar gas. We select a set of propagation models compatible with the recent B/C data from PAMELA, and find those providing minimal and maximal antiproton fluxes in different energy ranges. We use this result to determine the most conservative bounds on relevant Dark Matter (DM) annihilation channels: We find that the recent claim of a DM interpretation of a gamma-ray excess in the Galactic Center region cannot be ruled out by current antiproton data. Finally, we discuss the impact of the recently released preliminary data from AMS-02. In particular, we provide a reference model compatible with proton, helium and B/C spectra from this experiment. Remarkably, the main propagation parameters of this model are in perfect agreement with the best fit presented in our earlier statistical analyses. We also show that the antiproton-to-proton ratio does not...

  5. Relative Biological Effectiveness and Peripheral Damage of Antiproton Annihilation

    CERN Multimedia

    Kavanagh, J N; Kaiser, F; Tegami, S; Schettino, G; Kovacevic, S; Hajdukovic, D; Welsch, C P; Currell, F J; Toelli, H T; Doser, M; Holzscheiter, M; Herrmann, R; Timson, D J; Alsner, J; Landua, R; Knudsen, H; Comor, J; Moller, S P; Beyer, G

    2002-01-01

    The use of ions to deliver radiation to a body for therapeutic purposes has the potential to be significant improvement over the use of low linear energy transfer (LET) radiation because of the improved energy deposition profile and the enhanced biological effects of ions relative to photons. Proton therapy centers exist and are being used to treat patients. In addition, the initial use of heavy ions such as carbon is promising to the point that new treatment facilities are planned. Just as with protons or heavy ions, antiprotons can be used to deliver radiation to the body in a controlled way; however antiprotons will exhibit additional energy deposition due to annihilation of the antiprotons within the body. The slowing down of antiprotons in matter is similar to that of protons except at the very end of the range beyond the Bragg peak. Gray and Kalogeropoulos estimated the additional energy deposited by heavy nuclear fragments within a few millimeters of the annihilation vertex to be approximately 30 MeV (...

  6. Outer casing of the AA antiproton production target

    CERN Multimedia

    1979-01-01

    The first version of the antiproton production target was a tungsten rod, 11 cm long (actually a row of 11 rods, each 1 cm long) and 3 mm in diameter. The rod was embedded in graphite, pressure-seated into an outer casing made of stainless steel. The casing had fins for forced-air cooling.

  7. An Advanced Hadron Facility: Prospects and applicability to antiproton production

    International Nuclear Information System (INIS)

    An Advanced Hadron Facility is designed to address physics problems within and beyond the Standard Model. High fluxes of secondary beams are needed for the requisite precision tests and searches for very rare decay modes of mesons and baryons. Such high fluxes at useful secondary energies are readily obtained from high intensity, intermediate energy proton beams, which are also well suited to antiproton production. If the AHF primary proton beam were merely dumped into a beam stop, it would produce on the order of 1019 to 1020 antiprotons per operating year. Current collection techniques are not likely to be capable of absorbing more than one part in 103 of this production. Thus, an AHF provides both the immediate possibility of collecting quantities of antiprotons substantially beyond those available from the LEF discussed at this meeting, and for significant increases in the available antiproton supply upon the development (at an AHF) of more efficient collection methods. The prospects are presently good for the completion of an AHF in the late 1990's

  8. The Antiproton Depth Dose Curve Measured with Alanine Detectors

    DEFF Research Database (Denmark)

    Bassler, Niels; Hansen, Johnny Witterseh; Palmans, Hugo;

    2008-01-01

    In this paper we report on the measurement of the antiproton depth dose curve, with alanine detectors. The results are compared with simulations using the particle energy spectrum calculated by FLUKA, and using the track structure model of Hansen et Olsen for conversion of calculated dose...

  9. Planetary Rings

    CERN Document Server

    Tiscareno, Matthew S

    2011-01-01

    Planetary rings are the only nearby astrophysical disks, and the only disks that have been investigated by spacecraft. Although there are significant differences between rings and other disks, chiefly the large planet/ring mass ratio that greatly enhances the flatness of rings (aspect ratios as small as 1e-7), understanding of disks in general can be enhanced by understanding the dynamical processes observed at close-range and in real-time in planetary rings. We review the known ring systems of the four giant planets, as well as the prospects for ring systems yet to be discovered. We then review planetary rings by type. The main rings of Saturn comprise our system's only dense broad disk and host many phenomena of general application to disks including spiral waves, gap formation, self-gravity wakes, viscous overstability and normal modes, impact clouds, and orbital evolution of embedded moons. Dense narrow rings are the primary natural laboratory for understanding shepherding and self-stability. Narrow dusty...

  10. Planetary Rings

    Science.gov (United States)

    Gordon, M. K.; Araki, S.; Black, G. J.; Bosh, A. S.; Brahic, A.; Brooks, S. M.; Charnoz, S.; Colwell, J. E.; Cuzzi, J. N.; Dones, L.; Durisen, R. H.; Esposito, L. W.; Ferrari, C.; Festou, M.; French, R. G.; Giuliatti-Winter, S. M.; Graps, A. L.; Hamilton, D. P.; Horanyi, M.; Karjalainen, R. M.; Krivov, A. V.; Krueger, H.; Larson, S. M.; Levison, H. F.; Lewis, M. C.; Lissauer, J. J.; Murray, C. D.; Namouni, F.; Nicholson, P. D.; Olkin, C. B.; Poulet, F.; Rappaport, N. J.; Salo, H. J.; Schmidt, J.; Showalter, M. R.; Spahn, F.; Spilker, L. J.; Srama, R.; Stewart, G. R.; Yanamandra-Fisher, P.

    2002-08-01

    The past two decades have witnessed dramatic changes in our view and understanding of planetary rings. We now know that each of the giant planets in the Solar System possesses a complex and unique ring system. Recent studies have identified complex gravitational interactions between the rings and their retinues of attendant satellites. Among the four known ring systems, we see elegant examples of Lindblad and corotation resonances (first invoked in the context of galactic disks), electromagnetic resonances, spiral density waves and bending waves, narrow ringlets which exhibit internal modes due to collective instabilities, sharp-edged gaps maintained via tidal torques from embedded moonlets, and tenuous dust belts created by meteoroid impact onto, or collisions between, parent bodies. Yet, as far as we have come, our understanding is far from complete. The fundamental questions confronting ring scientists at the beginning of the twenty-first century are those regarding the origin, age and evolution of the various ring systems, in the broadest context. Understanding the origin and age requires us to know the current ring properties, and to understand the dominant evolutionary processes and how they influence ring properties. Here we discuss a prioritized list of the key questions, the answers to which would provide the greatest improvement in our understanding of planetary rings. We then outline the initiatives, missions, and other supporting activities needed to address those questions, and recommend priorities for the coming decade in planetary ring science.

  11. King Lear, la folie folliante et la naissance du sujet moderne dans la littérature anglaise

    Directory of Open Access Journals (Sweden)

    Tatjana Silec

    2012-12-01

    Full Text Available Le présent article a pour but de montrer que l’élaboration du personnage de fiction en tant qu’individu mû par des forces internes (désirs, volonté, etc. plutôt qu’externes (contexte social, genre du texte a commencé dans la littérature anglaise avec la figure du chevalier aliéné, qu’il soit réellement fou ou qu’il contrefasse la folie pour arriver à ses fins. C’est cette élaboration progressive qui prépare et rend possible l’apparition du personnage moderne, objet par excellence de la critique psychanalytique, dans le théâtre shakespearien. L’article prend comme exemple certains personnages de King Lear, pièce que Shakespeare place dans un Moyen Âge fantasmé à la limite des Âges Sombres, et montre qu’ils ont eu des prédécesseurs dans la littérature médiévale anglaise.

  12. Constraints on particle dark matter from cosmic-ray antiprotons

    International Nuclear Information System (INIS)

    Cosmic-ray antiprotons represent an important channel for dark matter indirect-detection studies. Current measurements of the antiproton flux at the top of the atmosphere and theoretical determinations of the secondary antiproton production in the Galaxy are in good agreement, with no manifest deviation which could point to an exotic contribution in this channel. Therefore, antiprotons can be used as a powerful tool for constraining particle dark matter properties. By using the spectrum of PAMELA data from 50 MV to 180 GV in rigidity, we derive bounds on the dark matter annihilation cross section (or decay rate, for decaying dark matter) for the whole spectrum of dark matter annihilation (decay) channels and under different hypotheses of cosmic-rays transport in the Galaxy and in the heliosphere. For typical models of galactic propagation, the constraints are strong, setting a lower bound on the dark matter mass of a ''thermal'' relic at about 40–80 GeV for hadronic annihilation channels. These bounds are enhanced to about 150 GeV on the dark matter mass, when large cosmic-rays confinement volumes in the Galaxy are considered, and are reduced to 3–4 GeV for annihilation to light quarks (no bound for heavy-quark production) when the confinement volume is small. Bounds for dark matter lighter than few tens of GeV are due to the low energy part of the PAMELA spectrum, an energy region where solar modulation is relevant: to this aim, we have implemented a detailed solution of the transport equation in the heliosphere, which allowed us not only to extend bounds to light dark matter, but also to determine the uncertainty on the constraints arising from solar modulation modelling. Finally, we estimate the impact of soon-to-come AMS-02 data on the antiproton constraints

  13. INITIAL COOLING EXPERIMENT (ICE)

    CERN Multimedia

    1979-01-01

    ICE was built in 1977, using the modified bending magnets of the g-2 muon storage ring (see 7405430). Its purpose was to verify the validity of stochastic and electron cooling for the antiproton project. Stochastic cooling proved a resounding success early in 1978 and the antiproton project could go ahead, now entirely based on stochastic cooling. Electron cooling was experimented with in 1979. The 26 kV equipment is housed in the cage to the left of the picture, adjacent to the "e-cooler" located in a straight section of the ring. With some modifications, the cooler was later transplanted into LEAR (Low Energy Antiproton Ring) and then, with further modifications, into the AD (Antiproton Decelerator), where it cools antiprotons to this day (2006). See also: 7711282, 7802099, 7809081.

  14. INITIAL COOLING EXPERIMENT (ICE)

    CERN Multimedia

    1978-01-01

    ICE was built in 1977, in a record time of 9 months, using the modified bending magnets of the g-2 muon storage ring. Its purpose was to verify the validity of stochastic and electron cooling for the antiproton project, to be launched in 1978. Already early in 1978, stochastic cooling proved a resounding success, such that the antiproton (p-pbar)project was entirely based on it. Tests of electron cooling followed later: protons of 46 MeV kinetic energy were cooled with an electron beam of 26 kV and 1.3 A. The cage seen prominently in the foreground houses the HV equipment, adjacent to the "cooler" installed in a straight section of the ring. With some modifications, the cooler was later transplanted into LEAR (Low Energy Antiproton Ring) and then, with further modifications, into the AD (Antiproton Decelerator), where it cools antiprotons to this day (2006). See also: 7711282, 7802099, 7908242.

  15. Partial wave analyses of antiproton-proton annihilations in flight

    Energy Technology Data Exchange (ETDEWEB)

    Pychy, Julian; Koch, Helmut; Kopf, Bertram; Wiedner, Ulrich [Institut fuer Experimentalphysik I, Ruhr-Universitaet Bochum (Germany)

    2015-07-01

    To investigate important aspects for the upcoming PANDA experiment, partial wave analyses (PWA) of anti pp-annihilation processes are carried out using data from the Crystal Barrel (LEAR) experiment. A coupled channel analysis of the three reactions resulting in the final states K{sup +}K{sup -}π{sup 0}, π{sup 0}π{sup 0}η and π{sup 0}ηη at a beam momentum of 900 MeV/c is currently in progress. Preliminary results on the determination of resonance contributions and of the spin density matrix (SDM) of different light mesons are presented. The elements of the SDM provide important information about the production process. Furthermore, results of the analyses of the channels ωπ{sup 0}, ωπ{sup 0}η and π{sup +}π{sup -}π{sup 0}π{sup 0} are discussed. These studies are focused on the determination of the contributing angular momenta of the anti pp-system as well as of the SDM of the ω meson. Significant spin-alignment effects depending on the production angle are visible here. These results are compared with those for the φ(1020) in the K{sup +}K{sup -}π{sup 0} channel. All analyses have been performed using PAWIAN, a common, object-oriented and easy-to-use PWA software that is being developed at the Ruhr-Universitaet Bochum. This presentation summarizes recent activities of the Crystal Barrel (LEAR) Collaboration.

  16. Secondary electron emission in antiproton-carbon foil collisions

    Energy Technology Data Exchange (ETDEWEB)

    Komaki, K.; Yamazaki, Y.; Kuroki, K. (Inst. of Physics, Coll. of Arts and Sciences, Univ. of Tokyo (Japan)); Andersen, L.H.; Horsdal-Pedersen, E.; Hvelplund, P.; Knudsen, H.; Moeller, S.P.; Uggerhoej, E. (Inst. of Physics, Univ. of Aarhus (Denmark)); Elsener, K. (CERN, Geneva (Switzerland))

    1991-04-01

    Energy spectra of electrons emitted in the forward direction by antiproton and proton bombardments on carbon foil targets were measured in the incident energy region from 500 to 750 keV. In the spectra for antiproton impact, no sharp anticusp, which is expected in place of the cusp in the case of the proton impact, is recognized and a small bump is found at 50 eV below the cusp energy. The spectral profile in the equivelocity region, including smearing out of the anticusp, together with the energy and intensity of the bump, is consistent with a theoretical prediction for wake-riding electrons based on the classical trajectory Monte Carlo method. (orig.).

  17. Dark matter for excess of AMS-02 positrons and antiprotons

    Directory of Open Access Journals (Sweden)

    Chuan-Hung Chen

    2015-07-01

    Full Text Available We propose a dark matter explanation to simultaneously account for the excess of antiproton-to-proton and positron power spectra observed in the AMS-02 experiment while having the right dark matter relic abundance and satisfying the current direct search bounds. We extend the Higgs triplet model with a hidden gauge symmetry of SU(2X that is broken to Z3 by a quadruplet scalar field, rendering the associated gauge bosons stable weakly-interacting massive particle dark matter candidates. By coupling the complex Higgs triplet and the SU(2X quadruplet, the dark matter candidates can annihilate into triplet Higgs bosons each of which in turn decays into lepton or gauge boson final states. Such a mechanism gives rise to correct excess of positrons and antiprotons with an appropriate choice of the triplet vacuum expectation value. Besides, the model provides a link between neutrino mass and dark matter phenomenology.

  18. Testing quantum chromodynamics in anti-proton reactions

    International Nuclear Information System (INIS)

    An experimental program with anti-protons at intermediate energy can serve as an important testing ground for QCD. Detailed predictions for exclusive cross sections at large momentum transfer based on perturbative QCD and the QCD sum rule form of the proton distribution amplitude are available for anti p p → γγ for both real and virtual photons. Meson-pair and lepton-pair final states also give sensitive tests of the theory. The production of charmed hadrons in exclusive anti p p channels may have a non-negligible cross section. Anti-proton interactions in a nucleus, particularly J/psi production, can play an important role in clarifying fundamental QCD issues, such as color transparency, critical length phenomena, and the validity of the reduced nuclear amplitude phenomenology

  19. A Good Statistics Study of Antiproton Interactions with Nuclei

    CERN Multimedia

    2002-01-01

    This experiment extends the study of inclusive pion production and the correlation between pions which result from hadron-nucleus collisions at intermediate and high energies to the antiproton-nucleus system. It is part of a long term systematic search for exotic nuclear phenomena. The correlation data will be used to extract, via pion interferometry, the size and coherence of the annihilation source in nuclei. In addition, the reaction @* + A @A p + A* will be studied to look for structure in the proton spectra which antiproton-nucleus bound states.\\\\ \\\\ The experimental system is based on a flexible, broad range, large acceptance (1~steradian) spectrometer which consists of an 80~cm diameter dipole magnet surrounded with detector arrays. These detectors provide momentum, energy loss, Cerenkov and time of flight information for up to ten ejectiles per event. Momentum resolution varies from 1\\% to 3\\%, depending on energy.

  20. Heating of nuclear matter and multifragmentation: antiprotons vs. pions

    International Nuclear Information System (INIS)

    Heating of nuclear matter with 8 GeV/c bar p and π- beams has been investigated in an experiment conducted at BNL AGS accelerator. All charged particles from protons to Z ≅ 16 were detected using the Indiana Silicon Sphere 4π array. Significant enhancement of energy deposition in high multiplicity events is observed for antiprotons compared to other hadron beams. The experimental trends are qualitatively consistent with predictions from an intranuclear cascade code

  1. Physics at the Fermilab Tevatron Proton-Antiproton Collider

    International Nuclear Information System (INIS)

    These lectures discuss a selection of QCD and Electroweak results from the CDF and D0 experiments at the Fermilab Tevatron Proton-Antiproton Collider. Results are presently based on data samples of about 20 pb-1 at a center-of-mass energy of 1.8 TeV. Results discussed include jet production, direct photon production, W mass and width measurements, the triboson coupling, and most exciting of all, evidence for top quark production

  2. The discovery of geomagnetically trapped cosmic ray antiprotons

    OpenAIRE

    Adriani, O.; Barbarino, G. C.; Bazilevskaya, G. A.; Bellotti, R.; M. Boezio; Bogomolov, E.A.; M. Bongi; Bonvicini, V.; Borisov, S.; Bottai, S.; Bruno, A.; F. Cafagna; Campana, D.; Carbone, R.; Carlson, P.

    2011-01-01

    The existence of a significant flux of antiprotons confined to Earth's magnetosphere has been considered in several theoretical works. These antiparticles are produced in nuclear interactions of energetic cosmic rays with the terrestrial atmosphere and accumulate in the geomagnetic field at altitudes of several hundred kilometers. A contribution from the decay of albedo antineutrons has been hypothesized in analogy to proton production by neutron decay, which constitutes the main source of tr...

  3. Antiprotons from dark matter annihilation in the Galaxy. Astrophysical uncertainties

    Energy Technology Data Exchange (ETDEWEB)

    Evoli, Carmelo [Chinese Academy of Sciences, Beijing (China). National Astronomical Observatories; Cholis, Ilias; Ullio, Piero [SISSA, Sezione di Trieste (Italy); INFN, Sezione di Trieste (Italy); Grasso, Dario [INFN, Sezione di Pisa (Italy); Maccione, Luca [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)

    2011-08-15

    The latest years have seen steady progresses in WIMP dark matter (DM) searches, with hints of possible signals suggested by both direct and indirect detection experiments. Antiprotons can play a key role validating those interpretations since they are copiously produced by WIMP annihilations in the Galactic halo, and the secondary antiproton background produced by Cosmic Ray (CR) interactions is predicted with fair accuracy and matches the observed spectrum very well. Using the publicly available numerical DRAGON code, we reconsider antiprotons as a tool to constrain DM models discussing its power and limitations. We provide updated constraints on a wide class of annihilating DM models by comparing our predictions against the most up-to-date anti p measurements, taking also into account the latest spectral information on the p, He and other CR nuclei fluxes. Doing that, we probe carefully the uncertainties associated to both secondary and DM originated antiprotons, by using a variety of distinctively different assumptions for the propagation of CRs and for the DM distribution in the Galaxy. We find that the impact of the astrophysical uncertainties on constraining the DM properties can be much stronger, up to a factor of {proportional_to}50, than the one due to uncertainties on the DM distribution ({proportional_to}2-6). Remarkably, even reducing the uncertainties on the propagation parameters derived by local observables, non-local effects can still change DM model constraints even by 50%. Nevertheless, current anti p data place tight constraints on DM models, excluding some of those suggested in connection with indirect and direct searches. Finally we discuss the power of upcoming CR spectral data from the AMS-02 observatory to drastically reduce the uncertainties discussed in this paper and estimate the expected sensitivity of this instrument to some sets of DM models. (orig.)

  4. Production of ultra slow antiprotons, its application to atomic collisions and atomic spectroscopy - ASACUSA project

    International Nuclear Information System (INIS)

    The Atomic Spectroscopy And Collisions Using Slow Antiprotons (ASACUSA) project aims at studying collision dynamics with slow antiprotons and high precision spectroscopy of antiprotonic atoms. To realize these purposes, the production of high quality ultra slow antiproton beams is essential, which is achieved by the combination of antiproton decelerator (AD) from 3 GeV to 5 MeV, a radio frequency quadrupole (RFQ) decelerator from 5 MeV to 50 keV, and finally an electromagnetic trap from 50 keV to 10 eV. From the atomic physics point of view, an antiproton is an extremely heavy electron and/or a negatively charged proton, i.e., the antiproton is a unique tool to shed light on collision dynamics from the other side of the world. In addition to this fundamentally important feature, the antiproton has also a big practical advantage, i.e., it annihilates with the target nuclei emitting several energetic pions, which provides high detection efficiency with very good time resolution. Many-body effects which are of great importance to several branches of science will be studied through ionization and antiprotonic atom formation processes under single collision conditions. Various antiprotonic atoms including protonium (p anti-p) are expected to be meta-stable in vacuum, which is never true for those in dense media except for antiprotonic helium. High precision spectroscopy of protonium will for the first time become feasible benefited by this meta-stability. The present review reports briefly the production scheme of ultra slow antiproton beams and several topics proposed in the ASACUSA project

  5. Bubble detector measurements of a mixed radiation field from antiproton annihilation

    CERN Document Server

    Bassler, Niels; Møller, Søren Pape; Petersen, Jørgen B.; Rahbek, Dennis; Uggerhøj, Ulrik I.

    2006-01-01

    In the light of recent progress in the study of the biological potential of antiproton tumour treatment it is important to be able to characterize the neutron intensity arising from antiproton annihilation using simple, compact and reliable detectors. The intensity of fast neutrons from antiproton annihilation on polystyrene has been measured with bubble detectors and a multiplicity has been derived as well as an estimated neutron equivalent dose. Additionally the sensitivity of bubble detectors towards protons was measured.

  6. Current status of antiproton impact ionization of atoms and molecules: theoretical and experimental perspectives

    DEFF Research Database (Denmark)

    Kirchner, Tom; Knudsen, Helge

    2011-01-01

    Experimental and theoretical progress in the field of antiproton-impact-induced ionization of atoms and molecules is reviewed. We describe the techniques used to measure ionization cross sections and give an overview of the experimental results supplemented by tables of all existing data. An...... status of our understanding of antiproton impact ionization. The related issues of energy loss measurements and antiproton therapy are briefly described and directions for possible future work are pointed out as well....

  7. SUPRAMITRAL RING

    Directory of Open Access Journals (Sweden)

    Rajesh G

    2011-11-01

    Full Text Available Supra mitral ring is a rare cause for congenital mitral valve obstr uction. The reported incidence of supramitral ring is 0.2-0.4% in general population and 8% in patients with congenital mitral valve disease. The condition is characterized by an abnormal ridge of connective tissue often circumferential in shape ,on the atrial side of the mitral valve encroaching on the orifice of the mitral valve. It may adhere to the leaflets of the valve and restrict their movements. Although a supramitral ring may be rarely nonobstructive, it often results in mitral valve inflow obstruction.

  8. Interpretation of the cosmic ray positron and antiproton fluxes

    CERN Document Server

    Lipari, Paolo

    2016-01-01

    The spectral shape of cosmic ray positrons and antiprotons has been accurately measured in the broad kinetic energy range 1-350 GeV. In the higher part of this range (E > 30 GeV) the e+ and pbar are both well described by power laws with spectral indices gamma[e+] = 2.77 +-0.02 and gamma[pbar] = 2.78 +- 0.04 that are approximately equal to each other and to the spectral index of protons. In the same energy range the positron/antiproton flux ratio has the approximately constant value 2.04+-0.04, that is consistent with being equal to the ratio e_/pbar calculated for the conventional mechanism of production, where the antiparticles are created as secondaries in the inelastic interactions of primary cosmic rays with interstellar gas. The positron/antiproton ratio at lower energy is significantly higher (reaching the approximate value e+/pbar = 100 for E around 1 GeV), but in the entire energy range 1-350 GeV, the flux ratio is consistent with being equal to ratio of the production rates in the conventional mecha...

  9. Search for antiproton-{sup 15}N bound state in PANDA

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Dexu [Helmholtz Institut Mainz, 55128 Mainz (Germany); Johannes Gutenberg Universitaet Mainz, Institut fuer Kernphysik, 55099 Mainz (Germany); Larionov, Alexei; Mishustin, Igor [Frankfurt Institute for Advanced Studies (FIAS), D-60438 Frankfurt am Main (Germany); National Research Center ' ' Kurchatov Institute' ' , 123182 Moscow (Russian Federation); Ma, Yue [RIKEN, Saitama 351-0198 (Japan); Maas, Frank [Helmholtz Institut Mainz, 55128 Mainz (Germany); Johannes Gutenberg Universitaet Mainz, Institut fuer Kernphysik, 55099 Mainz (Germany); GSI Helmholtzzentrum fuer Schwerionenforschung, GmbH, 64291 Darmstadt (Germany)

    2013-07-01

    In order to study the antiproton-nucleus potential (antimatter-mater potential), and prepare a possible experiment for the PANDA spectrometer at FAIR facility, we carried out a calculation with the Giessen-Boltzman-Uehling-Uhlenbeck(GiBUU) model. The calculation was performed for an antiproton beam energy 1.5 GeV and an {sup 16}O target. The interesting events, which provide information about the antiproton-{sup 15}N potential, are required to have one knocked-out proton in forward direction and two or more pions from the antiproton annihilation at rest. Preliminary results of these studies are presented.

  10. Single and double ionization of helium by fast antiproton and proton impact

    Energy Technology Data Exchange (ETDEWEB)

    Andersen, L.H.; Hvelplund, P.; Knudsen, H.; Mo-dash-barller, S.P.; Elsener, K.; Rensfelt, K.H.; Uggerho-dash-barj, E.

    1986-10-27

    The first ion-atom--collision data obtained with antiprotons are presented. We measured the single- and double-ionization cross section for 0.5-5-MeV antiprotons and protons colliding with helium. For ion energies above --2 MeV, the single-ionization cross section is the same for protons and antiprotons. However, surprisingly, the double-ionization cross section for antiprotons is approximately a factor of 2 larger than that for protons. The present data constitute a challenge for future theoretical models of charged-particle--atom collisions.

  11. Time-dependent density functional calculation of the energy loss of antiprotons colliding with metallic nanoshells

    Energy Technology Data Exchange (ETDEWEB)

    Quijada, M. [Departamento de Fisica de Materiales, Facultad de Quimicas UPV/EHU, Apartado 1072, 20080 San Sebastian (Spain); Donostia International Physics Center DIPC, P. Manuel de Lardizabal 4, 20018 San Sebastian (Spain); Borisov, A.G. [Donostia International Physics Center DIPC, P. Manuel de Lardizabal 4, 20018 San Sebastian (Spain); Universite Paris-Sud, Laboratoire des Collisions Atomiques et Moleculaires (France); CNRS, UMR 8625, Laboratoire des Collisions Atomiques et Moleculaires, LCAM, Batiment 351, UPS-11, Orsay, 91405 Orsay Cedex (France); Muino, R.D. [Donostia International Physics Center DIPC, P. Manuel de Lardizabal 4, 20018 San Sebastian (Spain); Centro de Fisica de Materiales, Centro Mixto CSIC-UPV/EHU, Edificio Korta, Avenida de Tolosa 72, 20018 San Sebastian (Spain)

    2008-06-15

    Time-dependent density functional theory is used to study the interaction between antiprotons and metallic nanoshells. The ground state electronic properties of the nanoshell are obtained in the jellium approximation. The energy lost by the antiproton during the collision is calculated and compared to that suffered by antiprotons traveling in metal clusters. The resulting energy loss per unit path length of material in thin nanoshells is larger than the corresponding quantity for clusters. It is shown that the collision process can be interpreted as the antiproton crossing of two nearly bi-dimensional independent metallic systems. (copyright 2008 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  12. Charged pion albedo induced by cosmic antiproton interactions with the lunar surface

    International Nuclear Information System (INIS)

    We report the calculations of the energy spectra and fluxes of single and double albedo charged pions generated by cosmic proton and antiproton interactions with the lunar surface. Properties of such spectra and related fluxes are investigated in order to clarify some important facets of the antiproton detection via charged pion albedo flux from the lunar surface. Pion albedo measurement may represent a novel approach for the identification of cosmic antiprotons using the lunar surface as a calorimeter. Future scientific programs on the Moon designed to measure antiproton flux may benefit from the results of these calculations. (author)

  13. Determinantal rings

    CERN Document Server

    Bruns, Winfried

    1988-01-01

    Determinantal rings and varieties have been a central topic of commutative algebra and algebraic geometry. Their study has attracted many prominent researchers and has motivated the creation of theories which may now be considered part of general commutative ring theory. The book gives a first coherent treatment of the structure of determinantal rings. The main approach is via the theory of algebras with straightening law. This approach suggest (and is simplified by) the simultaneous treatment of the Schubert subvarieties of Grassmannian. Other methods have not been neglected, however. Principal radical systems are discussed in detail, and one section is devoted to each of invariant and representation theory. While the book is primarily a research monograph, it serves also as a reference source and the reader requires only the basics of commutative algebra together with some supplementary material found in the appendix. The text may be useful for seminars following a course in commutative ring theory since a ...

  14. Storage rings for radioactive ion beams

    Science.gov (United States)

    Nolden, F.; Dimopoulou, C.; Dolinskii, A.; Steck, M.

    2008-10-01

    Storage rings for radioactive heavy ions can be applied for a wide range of experiments in atomic and nuclear physics. The rare isotope beams are produced in flight via fragmentation or fission of high-intensity primary ions and they circulate in the storage ring at moderately relativistic energies (typically between 0.1 GeV/u up to 1 GeV/u). Due to their production mechanism they are usually highly charged or even fully stripped. The circulating radioactive heavy ion beams can be used to measure nuclear properties such as masses and decay times, which, in turn, can depend strongly on the ionic charge state. The storage rings must have large acceptances and dynamic apertures. The subsequent application of stochastic precooling of the secondary ions which are injected with large transverse and longitudinal emittances, and electron cooling to reach very high phase space densities has turned out to be a helpful tool for experiments with short-lived ions having lifetimes down to a few seconds. Some of these experiments have already been performed at the experimental storage ring ESR at GSI. The storage ring complex of the FAIR project is intended to enhance significantly the range of experimental possibilities. It is planned to extend the scope of experimental possibilities to collisions with electron or antiproton beams.

  15. Impedances and beam stability issues of the Fermilab recycler ring

    Energy Technology Data Exchange (ETDEWEB)

    Ng, King-Yuen

    1996-04-01

    The Fermilab Recycler Ring (permanent magnets) will be built on top of the Fermilab Main Injector sharing the same tunnel; its main function is to recycle the anti-protons after a store in the Tevatron and to provide storage for them after after accumulation and cooling in the Accumulator. Estimates of coupling impedances show domination by space charge. Examination of longitudinal instabilities shows that microwave instability will not occur if there are only N = 2.53 x 10{sup 12} anti-protons in the beam. Longitudinal coupling-bunch instability during injection stacking does not appear possible because of long bunch lengths/short bunch gaps and lack of sharp resonances. Transverse instability, on the other hand, cannot be Landau damped by the momentum spread in the beam, but it can be cured by a small spread in the betatron tunes (either from space charge or an octupole).

  16. Simulation of an antiprotons beam applied to the radiotherapy; Simulacao de um feixe de antiprotons aplicado a radioterapia

    Energy Technology Data Exchange (ETDEWEB)

    Prata, Leonardo de Almeida

    2006-07-15

    Results for the interaction of a antiproton beam with constituent nuclei of the organic matter are presented. This method regards of the application of an computational algorithm to determine quantitatively the differential cross sections for the scattered particles, starting from the interaction of these antiprotons with the nuclei, what will allow in the future to draw the isodose curve for antiproton therapy, once these beams are expected to be used in cancer treatment soon. The calculation will be done through the application of the concepts of the method of intranuclear cascade, providing yield and differential cross sections of the scattered particles, present in the software MCMC. Th algorithm was developed based on Monte Carlo's method, already taking into account a validate code. The following physical quantities are presented: the yield of secondary particles, their spectral and angular distributions for these interactions. For the energy range taken into account the more important emitted particles are protons, neutrons and pions. Results shown that emitted secondary particles can modify the isodose curves, because they present high yield and energy for transverse directions. (author)

  17. Multiple collision effects on the antiproton production by high energy proton (100 GeV - 1000 GeV)

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, Hiroshi; Powell, J.

    1987-01-01

    Antiproton production rates which take into account multiple collision are calculated using a simple model. Methods to reduce capture of the produced antiprotons by the target are discussed, including geometry of target and the use of a high intensity laser. Antiproton production increases substantially above 150 GeV proton incident energy. The yield increases almost linearly with incident energy, alleviating space charge problems in the high current accelerator that produces large amounts of antiprotons.

  18. Measurement of the antiproton stopping power of gold - the Barkas effect

    Science.gov (United States)

    Medenwaldt, R.; Møller, S. P.; Uggerhøj, E.; Worm, T.; Hvelplund, P.; Knudsen, H.; Elsener, K.; Morenzoni, E.

    1991-05-01

    The stopping power of gold has been measured for antiprotons in the energy range 0.2-3 MeV using a novel time-of-flight technique. The antiproton stopping power is found to be less than half the equivalent proton stopping power near the electronic stopping power maximum. In the high-energy limit the two stopping powers merge.

  19. Measurement of the antiproton stopping power of gold - the Barkas effect

    Energy Technology Data Exchange (ETDEWEB)

    Medenwaldt, R.; Moeller, S.P.; Uggerhoej, E.; Worm, T. (Inst. for Synchrotron Radiation, Aarhus Univ. (Denmark)); Hvelplund, P.; Knudsen, H. (Inst. of Physics, Univ. of Aarhus (Denmark)); Elsener, K. (CERN, Geneva (Switzerland)); Morenzoni, E. (Paul Scherrer Inst., Villigen (Switzerland))

    1991-05-06

    The stopping power of gold has been measured for antiprotons in the energy range 0.2-3 MeV using a novel time-of-flight technique. The antiproton stopping power is found to be less than half the equivalent proton stopping power near the electronic stopping power maximum. In the high-energy limit the two stopping powers merge. (orig.).

  20. Ionization of atomic hydrogen by 30 1000 keV antiprotons

    Energy Technology Data Exchange (ETDEWEB)

    Knudsen, H.; Mikkelsen, U.; Paludan, K. [Institute of Physics and Astronomy, University of Aarhus, DK-8000 Aarhus C (Denmark); Kirsebom, K.; Moller, S.P.; Uggerhoj, E. [Institute for Synchrotron Radiation, University of Aarhus, DK-8000 Aarhus C (Denmark); Slevin, J. [Department of Experimental Physics, St. Patrick`s College, Maynooth (Ireland); Charlton, M. [Department of Physics and Astronomy, University College London, London WC1E 6BT (United Kingdom); Morenzoni, E. [Paul Scherrer Institut, Villigen, CH-4234 (Switzerland)

    1995-06-05

    Ionization in collisions between antiprotons and atomic hydrogen is perhaps the least complicated and most fundamental process that can be treated by atomic-collision theory. We present measurements of the ionization cross section for 30--1000 keV antiprotons colliding with atomic hydrogen.

  1. Comparison of Optimized Single and Multifield Irradiation Plans of Antiproton, Proton and Carbon Ion Beams

    DEFF Research Database (Denmark)

    Bassler, Niels; Kantemiris, Ioannis; Karaiskos, Pantelis;

    2010-01-01

    Antiprotons have been suggested as a possibly superior modality for radiotherapy, due to the energy released when antiprotons annihilate, which enhances the Bragg peak and introduces a high-LET component to the dose. However, concerns are expressed about the inferior lateral dose distribution...

  2. Antiproton small momentum transfer charge exchange scattering on protons at 30 GeV/c

    International Nuclear Information System (INIS)

    Antiproton charge exchange scattering on protons anti pp→anti nn is investigated with 30 GeV/c antiprotons at the IHEP accelerator. The experiment confirms the existence of a structure at small angles in the angular distribution of this reaction at high energies, observed earlier

  3. Topological rings

    CERN Document Server

    Warner, S

    1993-01-01

    This text brings the reader to the frontiers of current research in topological rings. The exercises illustrate many results and theorems while a comprehensive bibliography is also included. The book is aimed at those readers acquainted with some very basic point-set topology and algebra, as normally presented in semester courses at the beginning graduate level or even at the advanced undergraduate level. Familiarity with Hausdorff, metric, compact and locally compact spaces and basic properties of continuous functions, also with groups, rings, fields, vector spaces and modules, and with Zorn''s Lemma, is also expected.

  4. Segmented scintillation detectors with silicon photomultiplier readout for measuring antiproton annihilations

    CERN Document Server

    Sótér, A; Kobayashi, T; Barna, D; Horvath, D; Hori, M

    2014-01-01

    The Atomic Spectroscopy and Collisions Using Slow Antiprotons (ASACUSA) experiment at the Antiproton Decelerator (AD) facility of CERN constructed segmented scintillators to detect and track the charged pions which emerge from antiproton annihilations in a future superconducting radiofrequency Paul trap for antiprotons. A system of 541 cast and extruded scintillator bars were arranged in 11 detector modules which provided a spatial resolution of 17 mm. Green wavelength-shifting fibers were embedded in the scintillators, and read out by silicon photomultipliers which had a sensitive area of 1 x 1 mm^2. The photoelectron yields of various scintillator configurations were measured using a negative pion beam of momentum p ~ 1 GeV/c. Various fibers and silicon photomultipliers, fiber end terminations, and couplings between the fibers and scintillators were compared. The detectors were also tested using the antiproton beam of the AD. Nonlinear effects due to the saturation of the silicon photomultiplier were seen a...

  5. Discriminating between antihydrogen and mirror-trapped antiprotons in a minimum-B trap

    CERN Document Server

    Amole, C; Ashkezari, M D; Baquero-Ruiz, M; Bertsche, W; Butler, E; Cesar, C L; Chapman, S; Charlton, M; Deller, A; Eriksson, S; Fajans, J; Friesen, T; Fujiwara, M C; Gill, D R; Gutierrez, A; Hangst, J S; Hardy, W N; Hayden, M E; Humphries, A J; Hydomako, R; Kurchaninov, L; Jonsell, S; Madsen, N; Menary, S; Nolan, P; Olchanski, K; Olin, A; Povilus, A; Pusa, P; Robicheaux, F; Sarid, E; Silveira, D M; So, C; Storey, J W; Thompson, R I; van der Werf, D P; Wurtele, J S

    2012-01-01

    Recently, antihydrogen atoms were trapped at CERN in a magnetic minimum (minimum-B) trap formed by superconducting octupole and mirror magnet coils. The trapped antiatoms were detected by rapidly turning off these magnets, thereby eliminating the magnetic minimum and releasing any antiatoms contained in the trap. Once released, these antiatoms quickly hit the trap wall, whereupon the positrons and antiprotons in the antiatoms annihilated. The antiproton annihilations produce easily detected signals; we used these signals to prove that we trapped antihydrogen. However, our technique could be confounded by mirror-trapped antiprotons, which would produce seemingly-identical annihilation signals upon hitting the trap wall. In this paper, we discuss possible sources of mirror-trapped antiprotons and show that antihydrogen and antiprotons can be readily distinguished, often with the aid of applied electric fields, by analyzing the annihilation locations and times. We further discuss the general properties of antipr...

  6. Antihydrogen and mirror-trapped antiproton discrimination: Discriminating between antihydrogen and mirror-trapped antiprotons in a minimum-B trap

    OpenAIRE

    Amole, C.; Andresen, G. B.; Ashkezari, M. D.; Baquero-Ruiz, M.; Bertsche, W.; Butler, E.; Cesar, C. L.; S. Chapman; Charlton, M.; Deller, A.; Eriksson, S.; Fajans, J.; Friesen, T.; Fujiwara, M. C.; Gill, D. R.

    2012-01-01

    Recently, antihydrogen atoms were trapped at CERN in a magnetic minimum (minimum-B) trap formed by superconducting octupole and mirror magnet coils. The trapped antiatoms were detected by rapidly turning off these magnets, thereby eliminating the magnetic minimum and releasing any antiatoms contained in the trap. Once released, these antiatoms quickly hit the trap wall, whereupon the positrons and antiprotons in the antiatoms annihilated. The antiproton annihilations produce easily detected s...

  7. FAIR: The accelerator facility for antiproton and ion research

    Energy Technology Data Exchange (ETDEWEB)

    Sharkov, Boris [FAIR JCR GSI, Darmstad (Germany)

    2010-07-01

    This presentation outlines the current status of the facility for antiproton and ion research (FAIR). It is expected that the actual construction of the facility will commence in 2010 as the project has raised more than one billion euro in funding. The sequence and scope of the construction of the accelerator modules in accordance with modularized start version are described. Outstanding research opportunities offered by the modularized start version for all scientific FAIR communities from early on will allow to bridge the time until FAIR's completion with a world-leading research program. The green paper outlining a realistic path to achieve this goal is discussed.

  8. Proton-Proton and Proton-Antiproton Colliders

    CERN Document Server

    Scandale, Walter

    2014-01-01

    In the last five decades, proton–proton and proton–antiproton colliders have been the most powerful tools for high energy physics investigations. They have also deeply catalyzed innovation in accelerator physics and technology. Among the large number of proposed colliders, only four have really succeeded in becoming operational: the ISR, the SppbarS, the Tevatron and the LHC. Another hadron collider, RHIC, originally conceived for ion–ion collisions, has also been operated part-time with polarized protons. Although a vast literature documenting them is available, this paper is intended to provide a quick synthesis of their main features and key performance.

  9. Proton-Proton and Proton-Antiproton Colliders

    Science.gov (United States)

    Scandale, Walter

    2015-02-01

    In the last five decades, proton-proton and proton-antiproton colliders have been the most powerful tools for high energy physics investigations. They have also deeply catalyzed innovation in accelerator physics and technology. Among the large number of proposed colliders, only four have really succeeded in becoming operational: the ISR, the SppbarS, the Tevatron and the LHC. Another hadron collider, RHIC, originally conceived for ion-ion collisions, has also been operated part-time with polarized protons. Although a vast literature documenting them is available, this paper is intended to provide a quick synthesis of their main features and key performance.

  10. The antiproton depth–dose curve measured with alanine detectors

    CERN Document Server

    Bassler, Niels; Palmans, Hugo; Holzscheiter, Michael H; Kovacevic, Sandra

    2008-01-01

    n this paper we report on the measurement of the antiproton depth–dose curve, with alanine detectors. The results are compared with simulations using the particle energy spectrum calculated by FLUKA, and using the track structure model of Hansen and Olsen for conversion of calculated dose into response. A good agreement is observed between the measured and calculated relative effectiveness although an underestimation of the measured values beyond the Bragg-peak remains unexplained. The model prediction of response of alanine towards heavy charged particles encourages future use of the alanine detectors for dosimetry of mixed radiation fields.

  11. Ring interferometry

    CERN Document Server

    Malykin, Grigorii B; Zhurov, Alexei

    2013-01-01

    This monograph is devoted to the creation of a comprehensive formalism for quantitative description of polarized modes' linear interaction in modern single-mode optic fibers. The theory of random connections between polarized modes, developed in the monograph, allows calculations of the zero shift deviations for a fiber ring interferometer. The monograph addresses also the

  12. E-LEARING

    OpenAIRE

    Titrade Cristina; El Baaboua Florentina

    2009-01-01

    Electronic learning (or e-Learning or eLearning) is a type of Technology supported education/learning (TSL) where the medium of instruction is through computer technology, particularly involving digital technologies. E-learning has been defined as "pedago

  13. E-LEARING

    Directory of Open Access Journals (Sweden)

    El Baaboua Florentina

    2009-05-01

    Full Text Available Electronic learning (or e-Learning or eLearning is a type of Technology supported education/learning (TSL where the medium of instruction is through computer technology, particularly involving digital technologies. E-learning has been defined as "pedago

  14. Learing the 3Cs

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Chinese home appliance makers are trying to activate any link between computers, communication and consumer electronics It's a scene that has failed to materialize in the past, but companies in China are trying again: sitting in front of the television, the viewer surfs the Internet, buys things from online shops, plays online games and makes video phone calls. The TV will transform into a catch-all information appliance, to be used as computer and telephone. While the technology is already avail

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

    CERN Document Server

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

    2014-01-01

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

  16. Measurement of 0.25 endash 3.2 GeV antiprotons in the cosmic radiation

    International Nuclear Information System (INIS)

    The balloon-borne isotope matter-antimatter experiment (IMAX) was flown from Lynn Lake, Manitoba Canada on 16 endash 17 July 1992. Using velocity and magnetic rigidity to determine mass, we have directly measured the abundances of cosmic ray antiprotons and protons in the energy range from 0.25 to 3.2 GeV. Both the absolute flux of antiprotons and the antiproton/proton ratio are consistent with recent theoretical work in which antiprotons are produced as secondary products of cosmic ray interactions with the interstellar medium. This consistency implies a lower limit to the antiproton lifetime of ∼107 yr. copyright 1996 The American Physical Society

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

    CERN Document Server

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

    2006-01-01

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

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

    Science.gov (United States)

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

    2006-06-01

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

  19. Study of doubly strange systems using stored antiprotons

    Science.gov (United States)

    Singh, B.; Erni, W.; Krusche, B.; Steinacher, M.; Walford, N.; Liu, B.; Liu, H.; Liu, Z.; Shen, X.; Wang, C.; Zhao, J.; Albrecht, M.; Erlen, T.; Fink, M.; Heinsius, F.; Held, T.; Holtmann, T.; Jasper, S.; Keshk, I.; Koch, H.; Kopf, B.; Kuhlmann, M.; Kümmel, M.; Leiber, S.; Mikirtychyants, M.; Musiol, P.; Mustafa, A.; Pelizäus, M.; Pychy, J.; Richter, M.; Schnier, C.; Schröder, T.; Sowa, C.; Steinke, M.; Triffterer, T.; Wiedner, U.; Ball, M.; Beck, R.; Hammann, C.; Ketzer, B.; Kube, M.; Mahlberg, P.; Rossbach, M.; Schmidt, C.; Schmitz, R.; Thoma, U.; Urban, M.; Walther, D.; Wendel, C.; Wilson, A.; Bianconi, A.; Bragadireanu, M.; Caprini, M.; Pantea, D.; Patel, B.; Czyzycki, W.; Domagala, M.; Filo, G.; Jaworowski, J.; Krawczyk, M.; Lisowski, E.; Lisowski, F.; Michałek, M.; Poznański, P.; Płażek, J.; Korcyl, K.; Kozela, A.; Kulessa, P.; Lebiedowicz, P.; Pysz, K.; Schäfer, W.; Szczurek, A.; Fiutowski, T.; Idzik, M.; Mindur, B.; Przyborowski, D.; Swientek, K.; Biernat, J.; Kamys, B.; Kistryn, S.; Korcyl, G.; Krzemien, W.; Magiera, A.; Moskal, P.; Psyzniak, A.; Rudy, Z.; Salabura, P.; Smyrski, J.; Strzempek, P.; Wronska, A.; Augustin, I.; Böhm, R.; Lehmann, I.; Nicmorus Marinescu, D.; Schmitt, L.; Varentsov, V.; Al-Turany, M.; Belias, A.; Deppe, H.; Dzhygadlo, R.; Ehret, A.; Flemming, H.; Gerhardt, A.; Götzen, K.; Gromliuk, A.; Gruber, L.; Karabowicz, R.; Kliemt, R.; Krebs, M.; Kurilla, U.; Lehmann, D.; Löchner, S.; Lühning, J.; Lynen, U.; Orth, H.; Patsyuk, M.; Peters, K.; Saito, T.; Schepers, G.; Schmidt, C. J.; Schwarz, C.; Schwiening, J.; Täschner, A.; Traxler, M.; Ugur, C.; Voss, B.; Wieczorek, P.; Wilms, A.; Zühlsdorf, M.; Abazov, V. M.; Alexeev, G.; Arefiev, A.; Astakhov, V. I.; Barabanov, M. Yu.; Batyunya, B. V.; Davydov, Yu. I.; Dodokhov, V. Kh.; Efremov, A. A.; Fechtchenko, A.; Fedunov, A. G.; Galoyan, A.; Grigoryan, S.; Koshurnikov, E. K.; Lobanov, V. I.; Lobanov, Y. Yu.; Makarov, A. F.; Malinina, L. V.; Malyshev, V. L.; Olshevskiy, A.; Perevalova, E.; Piskun, A. A.; Pocheptsov, T.; Pontecorvo, G.; Rodionov, V.; Rogov, Y.; Salmin, R.; Samartsev, A.; Sapozhnikov, M. G.; Shabratova, G.; Skachkov, N. B.; Skachkova, A. N.; Strokovsky, E. A.; Suleimanov, M.; Teshev, R.; Tokmenin, V.; Uzhinsky, V.; Vodopyanov, A.; Zaporozhets, S. A.; Zhuravlev, N. I.; Zorin, A. G.; Branford, D.; Glazier, D.; Watts, D.; Böhm, M.; Britting, A.; Eyrich, W.; Lehmann, A.; Pfaffinger, M.; Uhlig, F.; Dobbs, S.; Seth, K.; Tomaradze, A.; Xiao, T.; Bettoni, D.; Carassiti, V.; Cotta Ramusino, A.; Dalpiaz, P.; Drago, A.; Fioravanti, E.; Garzia, I.; Savriè, M.; Akishina, V.; Kisel, I.; Kozlov, G.; Pugach, M.; Zyzak, M.; Gianotti, P.; Guaraldo, C.; Lucherini, V.; Bersani, A.; Bracco, G.; Macri, M.; Parodi, R. F.; Biguenko, K.; Brinkmann, K.; Di Pietro, V.; Diehl, S.; Dormenev, V.; Drexler, P.; Düren, M.; Etzelmüller, E.; Galuska, M.; Gutz, E.; Hahn, C.; Hayrapetyan, A.; Kesselkaul, M.; Kühn, W.; Kuske, T.; Lange, J. S.; Liang, Y.; Metag, V.; Nanova, M.; Nazarenko, S.; Novotny, R.; Quagli, T.; Reiter, S.; Rieke, J.; Rosenbaum, C.; Schmidt, M.; Schnell, R.; Stenzel, H.; Thöring, U.; Ullrich, M.; Wagner, M. N.; Wasem, T.; Wohlfarth, B.; Zaunick, H.; Ireland, D.; Rosner, G.; Seitz, B.; Deepak, P. N.; Kulkarni, A.; Apostolou, A.; Babai, M.; Kavatsyuk, M.; Lemmens, P.; Lindemulder, M.; Loehner, H.; Messchendorp, J.; Schakel, P.; Smit, H.; Tiemens, M.; van der Weele, J. C.; Veenstra, R.; Vejdani, S.; Dutta, K.; Kalita, K.; Kumar, A.; Roy, A.; Sohlbach, H.; Bai, M.; Bianchi, L.; Büscher, M.; Cao, L.; Cebulla, A.; Dosdall, R.; Gillitzer, A.; Goldenbaum, F.; Grunwald, D.; Herten, A.; Hu, Q.; Kemmerling, G.; Kleines, H.; Lehrach, A.; Nellen, R.; Ohm, H.; Orfanitski, S.; Prasuhn, D.; Prencipe, E.; Pütz, J.; Ritman, J.; Schadmand, S.; Sefzick, T.; Serdyuk, V.; Sterzenbach, G.; Stockmanns, T.; Wintz, P.; Wüstner, P.; Xu, H.; Zambanini, A.; Li, S.; Li, Z.; Sun, Z.; Xu, H.; Rigato, V.; Isaksson, L.; Achenbach, P.; Corell, O.; Denig, A.; Distler, M.; Hoek, M.; Karavdina, A.; Lauth, W.; Liu, Z.; Merkel, H.; Müller, U.; Pochodzalla, J.; Schlimme, S.; Sfienti, C.; Thiel, M.; Ahmadi, H.; Ahmed, S.; Bleser, S.; Capozza, L.; Cardinali, M.; Dbeyssi, A.; Deiseroth, M.; Feldbauer, F.; Fritsch, M.; Fröhlich, B.; Jasinski, P.; Kang, D.; Khaneft, D.; Klasen, R.; Leithoff, H. H.; Lin, D.; Maas, F.; Maldaner, S.; Martìnez Rojo, M.; Marta, M.; Michel, M.; Mora Espì, M. C.; Morales Morales, C.; Motzko, C.; Nerling, F.; Noll, O.; Pflüger, S.; Pitka, A.; Rodríguez Piñeiro, D.; Sanchez Lorente, A.; Steinen, M.; Valente, R.; Weber, T.; Zambrana, M.; Zimmermann, I.; Fedorov, A.; Korjik, M.; Missevitch, O.; Boukharov, A.; Malyshev, O.; Marishev, I.; Balanutsa, P.; Balanutsa, V.; Chernetsky, V.; Demekhin, A.; Dolgolenko, A.; Fedorets, P.; Gerasimov, A.

    2016-10-01

    Bound nuclear systems with two units of strangeness are still poorly known despite their importance for many strong interaction phenomena. Stored antiprotons beams in the GeV range represent an unparalleled factory for various hyperon-antihyperon pairs. Their outstanding large production probability in antiproton collisions will open the floodgates for a series of new studies of systems which contain two or even more units of strangeness at the P ‾ ANDA experiment at FAIR. For the first time, high resolution γ-spectroscopy of doubly strange ΛΛ-hypernuclei will be performed, thus complementing measurements of ground state decays of ΛΛ-hypernuclei at J-PARC or possible decays of particle unstable hypernuclei in heavy ion reactions. High resolution spectroscopy of multistrange Ξ--atoms will be feasible and even the production of Ω--atoms will be within reach. The latter might open the door to the | S | = 3 world in strangeness nuclear physics, by the study of the hadronic Ω--nucleus interaction. For the first time it will be possible to study the behavior of Ξ‾+ in nuclear systems under well controlled conditions.

  20. Light meson emission in (anti)proton induced reactions

    CERN Document Server

    Kuraev, E A; Tomasi-Gustafsson, E

    2015-01-01

    Reactions induced by high energy antiprotons on proton on nuclei are accompanied with large probability by the emission of a few mesons. Interesting phenomena can be observed and QCD tests can be performed, through the detection of one or more mesons. The collinear emission from high energy (anti)proton beams of a hard pion or vector meson, can be calculated similarly to the emission of a hard photon from an electron \\cite{Kuraev:2013izz}. This is a well known process in QED, and it is called the "Quasi-Real Electron method", where the incident particle is an electron and a hard photon is emitted leaving an 'almost on shell' electron impinging on the target \\cite{Baier:1973ms}. Such process is well known as Initial State Emission (ISR) method of scanning over incident energy, and can be used, in the hadron case, to produce different kind of particles in similar kinematical conditions. In case of emission of a charged light meson, $\\pi$ or $\\rho$-meson, in proton-proton(anti-proton) collisions, the meson can b...

  1. Ultra-low energy storage ring at FLAIR

    International Nuclear Information System (INIS)

    The Ultra-low energy electrostatic Storage Ring (USR) at the future Facility for Low-energy Antiproton and Ion Research (FLAIR) will provide cooled beams of antiprotons in the energy range between 300 keV down to 20 keV and possibly less. The USR has been completely redesigned over the past three years. The ring structure is based on a “split achromat” lattice that allows in-ring experiments with internal gas jet target. Beam parameters might be adjusted in a wide range: from very short pulses in the nanosecond regime to a Coasting beam. In addition, a combined fast and slow extraction scheme was developed that allows for providing external experiments with cooled beams of different time structure. Detailed investigations of the USR, including studies into the ring’s long term beam dynamics, life time, equilibrium momentum spread and equilibrium lateral spread during collisions with an internal target were carried out. New tools and beam handling techniques for diagnostics of ultra-low energy ions at beam intensities less than 106 were developed by the QUASAR Group. In this paper, progress on the USR project will be presented with an emphasis on the expected beam parameters available to the experiments at FLAIR.

  2. Efficient accumulation of antiprotons and positrons, production of slow mono-energetic beams, and their applications

    CERN Document Server

    Yamazaki, Yasunori

    2004-01-01

    Recent progress of ASACUSA (Atomic Spectroscopy And Collisions Using Slow Antiprotons) project, particularly the antiproton trapping and slow antiproton production, is discussed. An RFQD (Radio Frequency Quadrupole Decelerator) installed in the ASACUSA beam line has an excellent deceleration efficiency of 25% providing 10-130keV antiprotons, which improves the final accumulation efficiency at least one and half orders of magnitude. The decelerated antiprotons are then injected in a large volume multiring trap, stored, and electron-cooled. About 1 million antiprotons are successfully accumulated per one AD shot and 10-500eV antiprotons are extracted as a mono-energetic beam. A UHV compatible positron accumulation is newly developed combining electron plasma and an ion cloud, which yields an accumulation rate as high as 400e **+s/mCi, two and a half orders of magnitude higher than other UHV compatible schemes. A new scheme to synthesize a spin-polarized antihydrogen beam is also discussed, which will play a vit...

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

    Directory of Open Access Journals (Sweden)

    Mohammad Bagher Tavakoli

    2015-01-01

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

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

    Science.gov (United States)

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

    2015-01-01

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

  5. Measurements of Discrete Symmetries in the Neutral Kaon System with the CPLEAR (PS195) Experiment

    CERN Document Server

    Ruf, Thomas

    2015-01-01

    The antiproton storage ring LEAR offered unique opportunities to study the symmetries which exist between matter and antimatter. At variance with other approaches at this facility, CPLEAR was an experiment devoted to the study of T, CPT and CP symmetries in the neutral kaon system. It measured with high precision the time evolution of initially strangeness-tagged $K^0$ and $\\bar{K}^0$ states to determine the size of violations with respect to these symmetries in the context of a systematic study. In parallel, limits concerning quantum-mechanical predictions (EPR paradox, coherence of the wave function) or the equivalence principle of general relativity have been obtained. This article will first discuss briefly the unique low energy antiproton storage ring LEAR followed by a description of the CPLEAR experiment, including the basic formalism necessary to understand the time evolution of a neutral kaon state and the main results related to measurements of discrete symmetries in the neutral kaon system. An exce...

  6. Measurement of Antiproton-proton Cross-Sections at Low Antiproton Momenta

    CERN Multimedia

    2002-01-01

    The experiment is designed to measure four different cross sections in the momentum range 150~MeV/c to 600~MeV/c: 1)~~~~the differential elastic \\\\ \\\\ 2)~~~~the differential charge exchange\\\\ \\\\ 3)~~~~the annihilation into charged and neutral pions\\\\ \\\\ 4)~~~~and the total cross section via the optical theorem. \\\\ \\\\ The experiment allows one to search once again and with good precision for baryonium. Of special interest is the existence of the S-meson, for which a signal of about 20~MeV-mb was found in a 1981 experiment (performed in the East Hall).\\\\ \\\\ A second point of special interest is the momentum region below 300~MeV/c because the cross sections are basically unknown. We will be able to explore the momentum dependence of this region for the first time.\\\\ \\\\ The elastic cross section is measured by a cylindrical multiwire proportional chamber and a scintillator hodoscope placed around a scattering chamber under vacuum. The charge exchange cross section is measured by a ring of 32~anti-neutron detector...

  7. Golden Jubilee photos: Welcome to the antiworld

    CERN Multimedia

    2004-01-01

    Professor Walter Oelert, leader of the team which created the first atoms of antihydrogen at the LEAR (Low Energy Antiproton Ring).Antiparticles were predicted in the work of Paul Dirac in the 1920's, since when physicists have identified all the necessary antiparticle constituents of an antiparticle atom - antielectrons (positrons), antiprotons and antineutrons. However, an antihydrogen atom wasn't produced until the PS210 experiment at CERN in 1995. PS210 used the LEAR accelerator, which was then nearing the end of its lifetime (see Bulletin 28/04), so everything in the experiment had to work first time. After installing the equipment in spring 1995, the experiment took place in the autumn, in two hour periods over 4 weeks. The experiment team collided energetic antiprotons from LEAR with a heavy element, a challenge for them as well as the LEAR operators. Proving that antihydrogen atoms had been formed required several more weeks of data analysis, but the announcement that nine antihydrogen atoms had been ...

  8. Neutron fluence in antiproton radiotherapy, measurements and simulations

    DEFF Research Database (Denmark)

    Bassler, Niels; Holzscheiter, Michael H.; Petersen, Jørgen B.B.

    2010-01-01

    A significant part of the secondary particle spectrum from antiproton annihilation consists of fast neutrons, which may contribute to a significant dose background found outside the primary beam. Using a polystyrene phantom as a moderator, we have performed absolute measurements of the thermalized...... part of the fast neutron spectrum using Lithium-6 and -7 Fluoride TLD pairs. The experimental results are found to be in good agreement with simulations using the Monte Carlo particle transport code FLUKA. The thermal neutron kerma resulting from the measured thermal neutron fluence is insignificant...... compared to the contribution from fast neutrons. The results are found to be similar to values calculated for pion treatment, however exact modeling under more realistic treatment scenarios is still required to quantitatively compare these treatment modalities....

  9. On the Utility of Antiprotons as Drivers for Inertial Confinement Fusion

    Energy Technology Data Exchange (ETDEWEB)

    Perkins, L J; Orth, C D; Tabak, M

    2003-10-20

    By contrast to the large mass, complexity and recirculating power of conventional drivers for inertial confinement fusion (ICF), antiproton annihilation offers a specific energy of 90MJ/{micro}g and thus a unique form of energy packaging and delivery. In principle, antiproton drivers could provide a profound reduction in system mass for advanced space propulsion by ICF. We examine the physics underlying the use of antiprotons ({bar p}) to drive various classes of high-yield ICF targets by the methods of volumetric ignition, hotspot ignition and fast ignition. The useable fraction of annihilation deposition energy is determined for both {bar p}-driven ablative compression and {bar p}-driven fast ignition, in association with 0-D and 1-D target burn models. Thereby, we deduce scaling laws for the number of injected antiprotons required per capsule, together with timing and focal spot requirements. The kinetic energy of the injected antiproton beam required to penetrate to the desired annihilation point is always small relative to the deposited annihilation energy. We show that heavy metal seeding of the fuel and/or ablator is required to optimize local deposition of annihilation energy and determine that a minimum of {approx}3x10{sup 15} injected antiprotons will be required to achieve high yield (several hundred megajoules) in any target configuration. Target gains - i.e., fusion yields divided by the available p - {bar p} annihilation energy from the injected antiprotons (1.88GeV/{bar p}) - range from {approx}3 for volumetric ignition targets to {approx}600 for fast ignition targets. Antiproton-driven ICF is a speculative concept, and the handling of antiprotons and their required injection precision - temporally and spatially - will present significant technical challenges. The storage and manipulation of low-energy antiprotons, particularly in the form of antihydrogen, is a science in its infancy and a large scale-up of antiproton production over present supply

  10. First measurement of the antiproton-nucleus annihilation cross section at 125 keV

    CERN Document Server

    Aghai-Khozani, H; Corradini, M; De Salvador, D; Hayano, R; Hori, M; Kobayashi, T; Leali, M; Lodi-Rizzini, E; Mascagna, V; Prest, M; Seiler, D; Soter, A; Todoroki, K; Vallazza, E; Venturelli, L

    2015-01-01

    The first observation of in-flight antiproton-nucleus annihilation at ∼130 keV obtained with the ASACUSA detector has demonstrated that the measurement of the cross section of the process is feasible at such extremely low energies Aghai-Khozani, H., et al., Eur. Phys. J. Plus 127, 55 (2012). Here we present the results of the data analysis with the evaluations of the antiproton annihilation cross sections on carbon, palladium and platinum targets at 125 keV.

  11. Bubble detector measurements of a mixed radiation field from antiproton annihilation

    DEFF Research Database (Denmark)

    Bassler, Niels; Knudsen, Helge; Møller, Søren Pape;

    2006-01-01

    In the light of recent progress in the study of the biological potential of antiproton tumour treatment it is important to be able to characterize the neutron intensity arising from antiproton annihilation using simple, compact and reliable detectors. The intensity of fast neutrons from antiproto...... annihilation on polystyrene has been measured with bubble detectors and a multiplicity has been derived as well as an estimated neutron equivalent dose. Additionally the sensitivity of bubble detectors towards protons was measured....

  12. Antiproton, positron, and electron imaging with a microchannel plate/phosphor detector

    CERN Document Server

    Andresen, G B; Bowe, P D; Bray, C; Butler, E; Cesar, C L; Chapman, S; Charlton, M; Fajans, J; Fujiwara, M C; Gill, D R; Hangst, J S; Hardy, W N; Hayano, R S; Hayden, M E; Humphries, A J; Hydomako, R; Jørgensen, L V; Kerrigan, S J; Kurchaninov, L; Lambo, R; Madsen, N; Nolan, P; Olchanski, K; Olin, A; Povilus, A; Pusa, P; Sarid, E; Seif El Nasr, S; Silveira, D M; Storey, J W; Thompson, R I; van der Werf, D P; Yamazaki, Y

    2009-01-01

    A microchannel plate (MCP)/phosphor screen assembly has been used to destructively measure the radial profile of cold, confined antiprotons, electrons, and positrons in the ALPHA experiment, with the goal of using these trapped particles for antihydrogen creation and confinement. The response of the MCP to low energy (10-200 eV, <1 eV spread) antiproton extractions is compared to that of electrons and positrons.

  13. Technical design report for the PANDA (AntiProton Annihilations at Darmstadt) Straw Tube Tracker. Strong interaction studies with antiprotons

    Energy Technology Data Exchange (ETDEWEB)

    Erni, W.; Keshelashvili, I.; Krusche, B.; Steinacher, M. [Universitaet Basel, Basel (Switzerland); Heng, Y.; Liu, Z.; Liu, H.; Shen, X.; Wang, Q.; Xu, H. [Chinese Academy of Sciences, Institute of High Energy Physics, Beijing (China); Aab, A.; Albrecht, M.; Becker, J.; Csapo, A.; Feldbauer, F.; Fink, M.; Friedel, P.; Heinsius, F.H.; Held, T.; Klask, L.; Koch, H.; Kopf, B.; Leiber, S.; Leyhe, M.; Motzko, C.; Pelizaeus, M.; Pychy, J.; Roth, B.; Schroeder, T.; Schulze, J.; Sowa, C.; Steinke, M.; Trifterer, T.; Wiedner, U.; Zhong, J. [Universitaet Bochum I. Institut fuer Experimentalphysik, Bochum (Germany); Beck, R.; Bianco, S.; Brinkmann, K.T.; Hammann, C.; Hinterberger, F.; Kaiser, D.; Kliemt, R.; Kube, M.; Pitka, A.; Quagli, T.; Schmidt, C.; Schmitz, R.; Schnell, R.; Thoma, U.; Vlasov, P.; Walther, D.; Wendel, C.; Wuerschig, T.; Zaunick, H.G. [Rheinische Friedrich-Wilhelms-Universitaet Bonn, Bonn (Germany); Bianconi, A. [Universita di Brescia, Brescia (Italy); Bragadireanu, M.; Caprini, M.; Pantea, D.; Pantelica, D.; Pietreanu, D.; Serbina, L.; Tarta, P.D. [Institutul National de C and D pentru Fizica si Inginerie Nucleara ' ' Horia Hulubei' ' , Bukarest-Magurele (Romania); Kaplan, D. [IIT, Illinois Institute of Technology, Chicago (United States); Fiutowski, T.; Idzik, M.; Mindur, B.; Przyborowski, D.; Swientek, K. [AGH, University of Science and Technology, Cracow (Poland)] [and others

    2013-02-15

    This document describes the technical layout and the expected performance of the Straw Tube Tracker (STT), the main tracking detector of the PANDA target spectrometer. The STT encloses a Micro-Vertex-Detector (MVD) for the inner tracking and is followed in beam direction by a set of GEM stations. The tasks of the STT are the measurement of the particle momentum from the reconstructed trajectory and the measurement of the specific energy loss for a particle identification. Dedicated simulations with full analysis studies of certain proton-antiproton reactions, identified as being benchmark tests for the whole PANDA scientific program, have been performed to test the STT layout and performance. The results are presented, and the time lines to construct the STT are described. (orig.)

  14. Measurements of the Decays $B^0 \\to \\bar{D}^0\\proton\\antiproton$, $B^0 \\to \\bar{D}^{*0}\\proton\\antiproton$, $B^0 \\to D^{-}\\proton\\antiproton\\pi^+$, and $B^0 \\to D^{*-}\\proton\\antiproton\\pi^+$

    CERN Document Server

    Aubert, B; Bóna, M; Boutigny, D; Couderc, F; Karyotakis, Yu; Lees, J P; Poireau, V; Tisserand, V; Zghiche, A; Graugès-Pous, E; Palano, A; Pappagallo, M; Chen, J C; Qi, N D; Rong, G; Wang, P; Zhu, Y S; Eigen, G; Ofte, I; Stugu, B; Abrams, G S; Battaglia, M; Brown, D N; Button-Shafer, J; Cahn, R N; Charles, E; Day, C T; Gill, M S; Groysman, Y; Jacobsen, R G; Kadyk, J A; Kerth, L T; Kolomensky, Yu G; Kukartsev, G; Lynch, G; Mir, L M; Oddone, P J; Orimoto, T J; Pripstein, M; Roe, N A; Ronan, M T; Wenzel, W A; Barrett, M; Ford, K E; Harrison, T J; Hart, A J; Hawkes, C M; Morgan, S E; Watson, A T; Goetzen, K; Held, T; Koch, H; Lewandowski, B; Pelizaeus, M; Peters, K; Schröder, T; Steinke, M; Boyd, J T; Burke, J P; Cottingham, W N; Walker, D; Çuhadar-Dönszelmann, T; Fulsom, B G; Hearty, C; Knecht, N S; Mattison, T S; McKenna, J A; Khan, A; Kyberd, P; Saleem, M; Teodorescu, L; Blinov, V E; Bukin, A D; Druzhinin, V P; Golubev, V B; Onuchin, A P; Serednyakov, S I; Skovpen, Y I; Solodov, E P; Todyshev, K Y; Best, D S; Bondioli, M; Bruinsma, M; Chao, M; Curry, S; Eschrich, I; Kirkby, D; Lankford, A J; Lund, P; Mandelkern, M A; Mommsen, R K; Röthel, W; Stoker, D P; Abachi, S; Buchanan, C; Foulkes, S D; Gary, J W; Long, O; Shen, B C; Wang, K; Zhang, L; Hadavand, H K; Hill, E J; Paar, H P; Rahatlou, S; Sharma, V; Berryhill, J W; Campagnari, C; Cunha, A; Dahmes, B; Hong, T M; Kovalskyi, D; Richman, J D; Beck, T W; Eisner, A M; Flacco, C J; Heusch, C A; Kroseberg, J; Lockman, W S; Nesom, G; Schalk, T; Schumm, B A; Seiden, A; Spradlin, P; Williams, D C; Wilson, M G; Albert, J; Chen, E; Dvoretskii, A; Hitlin, D G; Narsky, I; Piatenko, T; Porter, F C; Ryd, A; Samuel, A; Andreassen, R; Mancinelli, G; Meadows, B T; Sokoloff, M D; Blanc, F; Bloom, P C; Chen, S; Ford, W T; Hirschauer, J F; Kreisel, A; Nauenberg, U; Olivas, A; Ruddick, W O; Smith, J G; Ulmer, K A; Wagner, S R; Zhang, J; Chen, A; Eckhart, E A; Soffer, A; Toki, W H; Wilson, R J; Winklmeier, F; Zeng, Q; Altenburg, D D; Feltresi, E; Hauke, A; Jasper, H; Spaan, B; Brandt, T; Klose, V; Lacker, H M; Mader, W F; Nogowski, R; Petzold, A; Schubert, J; Schubert, K R; Schwierz, R; Sundermann, J E; Volk, A; Bernard, D; Bonneaud, G R; Grenier, P; Latour, E; Thiebaux, C; Verderi, M; Bard, D J; Clark, P J; Gradl, W; Muheim, F; Playfer, S; Robertson, A I; Xie, Y; Andreotti, M; Bettoni, D; Bozzi, C; Calabrese, R; Cibinetto, G; Luppi, E; Negrini, M; Petrella, A; Piemontese, L; Prencipe, E; Anulli, F; Baldini-Ferroli, R; Calcaterra, A; De Sangro, R; Finocchiaro, G; Pacetti, S; Patteri, P; Peruzzi, I M; Piccolo, M; Rama, M; Zallo, A; Buzzo, A; Capra, R; Contri, R; Lo Vetere, M; Macri, M M; Monge, M R; Passaggio, S; Patrignani, C; Robutti, E; Santroni, A; Tosi, S; Brandenburg, G; Chaisanguanthum, K S; Morii, M; Wu, J; Dubitzky, R S; Marks, J; Schenk, S; Uwer, U; Bhimji, W; Bowerman, D A; Dauncey, P D; Egede, U; Flack, R L; Gaillard, J R; Nash, J A; Nikolich, M B; Panduro-Vazquez, W; Chai, X; Charles, M J; Mallik, U; Meyer, N T; Ziegler, V; Cochran, J; Crawley, H B; Dong, L; Eyges, V; Meyer, W T; Prell, S; Rosenberg, E I; Rubin, A E; Gritsan, A V; Fritsch, M; Schott, G; Arnaud, N; Davier, M; Grosdidier, G; Höcker, A; Le Diberder, F R; Lepeltier, V; Lutz, A M; Oyanguren, A; Pruvot, S; Rodier, S; Roudeau, P; Schune, M H; Stocchi, A; Wang, W F; Wormser, G; Cheng, C H; Lange, D J; Wright, D M; Chavez, C A; Forster, I J; Fry, J R; Gabathuler, E; Gamet, R; George, K A; Hutchcroft, D E; Payne, D J; Schofield, K C; Touramanis, C; Bevan, A J; Di Lodovico, F; Menges, W; Sacco, R; Brown, C L; Cowan, G; Flächer, H U; Hopkins, D A; Jackson, P S; McMahon, T R; Ricciardi, S; Salvatore, F; Davis, C L; Allison, J; Barlow, N R; Barlow, R J; Chia, Y M; Edgar, C L; Kelly, M P; Lafferty, G D; Naisbit, M T; Williams, J C; Yi, J I; Chen, C; Hulsbergen, W D; Jawahery, A; Lae, C K; Roberts, D A; Simi, G; Blaylock, G; Dallapiccola, C; Hertzbach, S S; Li, X; Moore, T B; Saremi, S; Stängle, H; Willocq, S Y; Cowan, R; Koeneke, K; Sciolla, G; Sekula, S J; Spitznagel, M; Taylor, F; Yamamoto, R K; Kim, H; Patel, P M; Potter, C T; Robertson, S H; Lazzaro, A; Lombardo, V; Palombo, F; Bauer, J M; Cremaldi, L; Eschenburg, V; Godang, R; Kroeger, R; Reidy, J; Sanders, D A; Summers, D J; Zhao, H W; Brunet, S; Côté, D; Simard, M; Taras, P; Viaud, F B; Nicholson, H; Cavallo, N; De Nardo, Gallieno; Del Re, D; Fabozzi, F; Gatto, C; Lista, L; Monorchio, D; Piccolo, D; Sciacca, C; Baak, M; Bulten, H; Raven, G; Snoek, H L; Jessop, C P; LoSecco, J M; Allmendinger, T; Benelli, G; Gan, K K; Honscheid, K; Hufnagel, D; Jackson, P D; Kagan, H; Kass, R; Pulliam, T; Rahimi, A M; Ter-Antonian, R; Wong, Q K; Blount, N L; Brau, J E; Frey, R; Igonkina, O; Lu, M; Rahmat, R; Sinev, N B; Strom, D; Strube, J; Torrence, E; Galeazzi, F; Gaz, A; Margoni, M; Morandin, M; Pompili, A; Posocco, M; Rotondo, M; Simonetto, F; Stroili, R; Voci, C; Benayoun, M; Chauveau, J; David, P; Del Buono, L; La Vaissière, C de; Hamon, O; Hartfiel, B L; John, M J J; Leruste, P; Malcles, J; Ocariz, J; Roos, L; Therin, G; Behera, P K; Gladney, L; Panetta, J; Biasini, M; Covarelli, R; Pioppi, M; Angelini, C; Batignani, G; Bettarini, S; Bucci, F; Calderini, G; Carpinelli, M; Cenci, R; Forti, F; Giorgi, M A; Lusiani, A; Marchiori, G; Mazur, M A; Morganti, M; Neri, N; Paoloni, E; Rizzo, G; Walsh, J; Haire, M; Judd, D; Wagoner, D E; Biesiada, J; Danielson, N; Elmer, P; Lau, Y P; Lü, C; Olsen, J; Smith, A J S; Telnov, A V; Bellini, F; Cavoto, G; D'Orazio, A; Di Marco, E; Faccini, R; Ferrarotto, F; Ferroni, F; Gaspero, M; Li Gioi, L; Mazzoni, M A; Morganti, S; Piredda, G; Polci, F; Safai-Tehrani, F; Voena, C; Ebert, M; Schröder, H; Waldi, R; Adye, T; De Groot, N; Franek, B; Olaiya, E O; Wilson, F F; Emery, S; Gaidot, A; Ganzhur, S F; Hamel de Monchenault, G; Kozanecki, Witold; Legendre, M; Mayer, B; Vasseur, G; Yéche, C; Zito, M; Park, W; Purohit, M V; Weidemann, A W; Wilson, J R; Allen, M T; Aston, D; Bartoldus, R; Bechtle, P; Berger, N; Boyarski, A M; Claus, R; Coleman, J P; Convery, M R; Cristinziani, M; Dingfelder, J C; Dong, D; Dorfan, J; Dubois-Felsmann, G P; Dujmic, D; Dunwoodie, W M; Field, R C; Glanzman, T; Gowdy, S J; Graham, M T; Halyo, V; Hast, C; Hrynóva, T; Innes, W R; Kelsey, M H; Kim, P; Kocian, M L; Leith, D W G S; Li, S; Libby, J; Luitz, S; Lüth, V; Lynch, H L; MacFarlane, D B; Marsiske, H; Messner, R; Müller, D R; O'Grady, C P; Ozcan, V E; Perazzo, A; Perl, M; Ratcliff, B N; Roodman, A; Salnikov, A A; Schindler, R H; Schwiening, J; Snyder, A; Stelzer, J; Su, D; Sullivan, M K; Suzuki, K; Swain, S K; Thompson, J M; Vavra, J; Van Bakel, N; Weaver, M; Weinstein, A J R; Wisniewski, W J; Wittgen, M; Wright, D H; Yarritu, A K; Yi, K; Young, C C; Burchat, P R; Edwards, A J; Majewski, S A; Petersen, B A; Roat, C; Wilden, L; Ahmed, S; Alam, M S; Bula, R; Ernst, J A; Jain, V; Pan, B; Saeed, M A; Wappler, F R; Zain, S B; Bugg, W; Krishnamurthy, M; Spanier, S M; Eckmann, R; Ritchie, J L; Satpathy, A; Schilling, C J; Schwitters, R F; Izen, J M; Kitayama, I; Lou, X C; Ye, S; Bianchi, F; Gallo, F; Gamba, D; Bomben, M; Bosisio, L; Cartaro, C; Cossutti, F; Della Ricca, G; Dittongo, S; Grancagnolo, S; Lanceri, L; Vitale, L; Azzolini, V; Martínez-Vidal, F; Banerjee, S; Bhuyan, B; Brown, C M; Fortin, D; Hamano, K; Kowalewski, R V; Nugent, I M; Roney, J M; Sobie, R J; Back, J J; Harrison, P F; Latham, T E; Mohanty, G B; Band, H R; Chen, X; Cheng, B; Dasu, S; Datta, M; Eichenbaum, A M; Flood, K T; Hollar, J J; Johnson, J R; Kutter, P E; Li, H; Liu, R; Mellado, B; Mihályi, A; Mohapatra, A K; Pan, Y; Pierini, M; Prepost, R; Tan, P; Wu, S L; Yu, Z; Neal, H

    2006-01-01

    We present measurements of branching fractions of $B^0$ decays to multi-body final states containing protons, based on 232 million $\\Upsilon(4S)\\to B\\bar{B}$ decays collected with the BaBar detector at the SLAC PEP-II asymmetric-energy $B$ factory. We measure the branching fractions ${\\cal B}(B^0 \\to \\bar{D}^0\\proton\\antiproton)=(1.13\\pm0.06\\pm0.08)\\times 10^{-4}$, ${\\cal B}(B^0 \\to \\bar{D}^{*0}\\proton\\antiproton)=(1.01\\pm0.10\\pm0.09)\\times 10^{-4}$, ${\\cal B}(B^0 \\to D^{-}\\proton\\antiproton\\pi^+)=(3.38\\pm0.14\\pm0.29)\\times 10^{-4}$, and ${\\cal B}(B^0 \\to D^{*-}\\proton\\antiproton\\pi^+)=(4.81\\pm0.22\\pm0.44)\\times 10^{-4}$ where the first error is statistical and the second systematic. We present a search for the charmed pentaquark state, $\\Theta_c(3100)$ observed by H1 and put limits on the branching fraction ${\\cal B} (B^0 \\to \\Theta_c \\antiproton\\pi^+)\\times{\\cal B}(\\Theta_c \\to D^{*-}\\proton)<14\\times10^{-6}$ and ${\\cal B}(B^0 \\to \\Theta_c \\antiproton\\pi^+)\\times{\\cal B}(\\Theta_c\\to D^-\\proton)<9\\time...

  15. P-986 Letter of Intent: Medium-Energy Antiproton Physics at Fermilab

    Energy Technology Data Exchange (ETDEWEB)

    Asner, David M.; /Carleton U.; Phillips, Thomas J.; /Duke U.; Apollinari, Giorgio; Broemmelsiek, Daniel R.; Brown, Charles N.; Christian, David C.; Derwent, Paul; Gollwitzer, Keith; Hahn, Alan; Papadimitriou, Vaia; Stefanski, Ray; /Fermilab /INFN, Ferrara /Hbar Technol., West Chicago /IIT, Chicago /CHEP, Taegu /Luther Coll. /Michigan U. /Northwestern U. /Notre Dame U. /St. Xavier U., Chicago

    2009-02-05

    Fermilab has long had the world's most intense antiproton source. Despite this, the opportunities for medium-energy antiproton physics at Fermilab have been limited in the past and - with the antiproton source now exclusively dedicated to serving the needs of the Tevatron Collider - are currently nonexistent. The anticipated shutdown of the Tevatron in 2010 presents the opportunity for a world-leading medium-energy antiproton program. We summarize the current status of the Fermilab antiproton facility and review some physics topics for which the experiment we propose could make the world's best measurements. Among these, the ones with the clearest potential for high impact and visibility are in the area of charm mixing and CP violation. Continued running of the Antiproton Source following the shutdown of the Tevatron is thus one of the simplest ways that Fermilab can restore a degree of breadth to its future research program. The impact on the rest of the program will be minor. We request a small amount of effort over the coming months in order to assess these issues in more detail.

  16. Measurement of the stopping power of silicon for antiprotons between 0. 2 and 3 MeV

    Energy Technology Data Exchange (ETDEWEB)

    Medenwaldt, R.; Moeller, S.P.; Uggerhoej, E.; Worm, T. (Inst. for Synchrotron Radiation, Aarhus Univ. (Denmark)); Hvelplund, P.; Knudsen, H. (Inst. of Physics, Aarhus Univ. (Denmark)); Elsener, K. (CERN, Geneva (Switzerland)); Morenzoni, E. (Paul Scherrer Inst., Villigen (Switzerland))

    1991-05-01

    Our previous measurement of the stopping power of silicon power of silicon for antiprotons has been extended down to 200 keV. The antiproton stopping power is found to be more than 30% lower than that for equivelocity protons at 200 keV. The ''Z{sub 1}{sup 3} contribution'' to the stopping power (the Barkas effect) is deduced by comparing the stopping power for protons and antiprotons. Comparisons to theoretical estimates are made. (orig.).

  17. Measurement of the stopping power of silicon for antiprotons between 0.2 and 3 MeV

    Science.gov (United States)

    Medenwaldt, R.; Møller, S. P.; Uggerhøj, E.; Worm, T.; Hvelplund, P.; Knudsen, H.; Elsener, K.; Morenzoni, E.

    1991-05-01

    Our previous measurement of the stopping power of silicon for antiprotons has been extended down to 200 keV. The antiproton stopping power is found to be more than 30% lower than that for equivelocity protons at 200 keV. The " Z13 contribution" to the stopping power (the Barkas effect) is deduced by comparing the stopping power for protons and antiprotons. Comparisons to theoretical estimates are made.

  18. Measurement of the Z31 contribution to the stopping power using MeV protons and antiprotons: The Barkas effect

    Science.gov (United States)

    Andersen, L. H.; Hvelplund, P.; Knudsen, H.; Möller, S. P.; Pedersen, J. O. P.; Uggerhöj, E.; Elsener, K.; Morenzoni, E.

    1989-04-01

    The stopping power for antiprotons has been measured for the first time. The antiproton stopping power of silicon is found to be 3%-19% lower than for equivelocity protons over the energy range 3.01 to 0.538 MeV. The ``Z31 contribution'' to the stopping power (the Barkas effect) is deduced by comparing the stopping power for protons and antiprotons.

  19. Experiences with permanent magnets at the Fermilab recycler ring

    CERN Document Server

    Volk, James T

    2012-01-01

    In order to achieve higher luminosities in Run II a separate antiproton storage ring was built in the Main Injector tunnel. To reduce both construction and operations costs permanent magnets were used. This paper discusses the design criterion and specifications, including temperature dependence, longitudinal uniformity, and adjusting of the higher harmonics of the magnets. The design tolerances for a storage ring are more stringent than for a single pass beam line. The difference between the measured and ideal central field for each magnet was held to better than 0.1%. The temperature stability for all magnets was set to better than 0.01% per degree Celsius. Higher order harmonics relative to the central field were set to less than 0.01%. This was done for all 484 permanent magnet that were built.

  20. Prime rings with PI rings of constants

    CERN Document Server

    Kharchenko, V K; Rodríguez-Romo, S

    1996-01-01

    It is shown that if the ring of constants of a restricted differential Lie algebra with a quasi-Frobenius inner part satisfies a polynomial identity (PI) then the original prime ring has a generalized polynomial identitiy (GPI). If additionally the ring of constants is semiprime then the original ring is PI. The case of a non-quasi-Frobenius inner part is also considered.

  1. Weakly Dual Rings

    Institute of Scientific and Technical Information of China (English)

    魏俊潮; 孙建华

    2004-01-01

    In This paper, the concept of weakly dual ring is introduced, which is a proper generalization of the dual ring. If R is a right weakly dual ring, then (1)Z(RR) = J(R); (2) If R is also a zero-division power ring, then R is a right AP-injective ring. In addition, some properties of weakly dual rings are given.

  2. Radical theory of rings

    CERN Document Server

    Gardner, JW

    2003-01-01

    Radical Theory of Rings distills the most noteworthy present-day theoretical topics, gives a unified account of the classical structure theorems for rings, and deepens understanding of key aspects of ring theory via ring and radical constructions. Assimilating radical theory's evolution in the decades since the last major work on rings and radicals was published, the authors deal with some distinctive features of the radical theory of nonassociative rings, associative rings with involution, and near-rings. Written in clear algebraic terms by globally acknowledged authorities, the presentation

  3. Constraining pre big-bang-nucleosynthesis expansion using cosmic antiprotons

    Energy Technology Data Exchange (ETDEWEB)

    Schelke, M. [Istituto Nazionale di Fisica Nucleare, Torino (Italy); Catena, R. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Fornengo, N. [Torino Univ. (Italy). Dipt. di Fisica Teorica]|[Istituto Nazionale di Fisica Nucleare, Torino (Italy); Masiero, A. [Pavoa Univ. (Italy). Dipt. di Fisica]|[Istituto Nazionale di Fisica Nucleare, Padova (Italy); Pietroni, M. [Istituto Nazionale di Fisica Nucleare, Padova (Italy)

    2006-06-15

    A host of dark energy models and non-standard cosmologies predict an enhanced Hubble rate in the early Universe: perfectly viable models, which satisfy Big Bang Nucleosynthesis (BBN), cosmic microwave background and general relativity tests, may nevertheless lead to enhancements of the Hubble rate up to many orders of magnitude. In this paper we show that strong bounds on the pre-BBN evolution of the Universe may be derived, under the assumption that dark matter is a thermal relic, by combining the dark matter relic density bound with constraints coming from the production of cosmic-ray antiprotons by dark matter annihilation in the Galaxy. The limits we derive can be sizable and apply to the Hubble rate around the temperature of dark matter decoupling. For dark matter masses lighter than 100 GeV, the bound on the Hubble-rate enhancement ranges from a factor of a few to a factor of 30, depending on the actual cosmological model, while for a mass of 500 GeV the bound falls in the range 50-500. Uncertainties in the derivation of the bounds and situations where the bounds become looser are discussed. We finally discuss how these limits apply to some specific realizations of non-standard cosmologies: a scalar-tensor gravity model, kination models and a Randall-Sundrum D-brane model. (Orig.)

  4. Antiproton Flux in Cosmic Ray Propagation Models with Anisotropic Diffusion

    CERN Document Server

    Grajek, Phillip

    2010-01-01

    Recently a cosmic ray propagation model has been introduced, where anisotropic diffusion is used as a mechanism to allow for $\\mathcal{O}(100)$ km/s galactic winds. This model predicts a reduced antiproton background flux, suggesting an excess is being observed. We implement this model in GALPROP v50.1 and perform a $\\chi^2$ analysis for B/C, $^{10}$Be/$^{9}$Be, and the recent PAMELA $\\bar{p}/p$ datasets. By introducing a power-index parameter $\\alpha$ that dictates the dependence of the diffusion coefficient $D_{xx}$ on height $|z|$ away from the galactic plane, we confirm that isotropic diffusion models with $\\alpha=0$ cannot accommodate high velocity convective winds suggested by ROSAT, while models with $\\alpha=1$ ($D_{xx}\\propto |z|$) can give a very good fit. A fit to B/C and $^{10}$Be/$^{9}$Be data predicts a lower $\\bar{p}/p$ flux ratio than the PAMELA measurement at energies between approximately 2 GeV to 20 GeV. A combined fit including in addition the $\\bar{p}/p$ data is marginal, suggesting only a...

  5. Studying the potential of antihyperons in nuclei with antiprotons

    International Nuclear Information System (INIS)

    The interaction between an antibaryon and a nucleus may shed light on the short range antibaryon-baryon force in a unique way. However, because of the deep imaginary part of the nuclear potential of antibaryons, the physics of antihyperons in nuclei is hitherto an uncharted territory. Recently it was proposed to use transverse momentum correlations of exclusively produced antihyperon-hyperon pairs in antiproton-nucleus collisions to obtain information on the antihyperon potentials relative to that of the corresponding hyperon. In the present study we use the Giessen Boltzmann-Uehling- Uhlenbeck Transportmodell (GiBUU) to explore the production of exclusive hyperon-antihyperon pairs close to threshold. Unlike the schematic calculation, these GiBBU simulations take e.g. important rescattering effects into account. In case of anti p + 20Ne → anti ΛΛ+X we confirm a significant sensitivity of transverse momentum correlations to the nuclear potential of Λs. We also explore the feasibility of such measurements at the PANDA experiment of the international facility FAIR.

  6. Near-threshold behavior of positronium-antiproton scattering

    Science.gov (United States)

    Fabrikant, I. I.; Bray, A. W.; Kadyrov, A. S.; Bray, I.

    2016-07-01

    Using the convergent close-coupling theory we study the threshold behavior of cross sections for positronium (Ps) of energy E scattering on antiprotons. In the case of Ps (1 s ) elastic scattering, simple power laws are observed for all partial waves studied. The partial-wave summed cross section is nearly constant, and dominates the antihydrogen formation cross section at all considered energies, even though the latter is exothermic and behaves as 1 /E1 /2 . For Ps (2 s ), oscillations spanning orders of magnitude on top of the 1 /E behavior are found in the elastic and quasielastic cross sections. The antihydrogen formation is influenced by dipole-supported resonances below the threshold of inelastic processes. Resonance energies form a geometric progression relative to the threshold. The exothermic antihydrogen formation cross sections behave as 1 /E at low energies, but are oscillation free. We demonstrate that all these rich features are reproduced by the threshold theory developed by Gailitis [J. Phys. B: At. Mol. Phys. 15, 3423 (1982), 10.1088/0022-3700/15/19/012].

  7. Antiproton constraints on dark matter annihilations from internal electroweak bremsstrahlung

    International Nuclear Information System (INIS)

    If the dark matter particle is a Majorana fermion, annihilations into two fermions and one gauge boson could have, for some choices of the parameters of the model, a non-negligible cross-section. Using a toy model of leptophilic dark matter, we calculate the constraints on the annihilation cross-section into two electrons and one weak gauge boson from the PAMELA measurements of the cosmic antiproton-to-proton flux ratio. Furthermore, we calculate the maximal astrophysical boost factor allowed in the Milky Way under the assumption that the leptophilic dark matter particle is the dominant component of dark matter in our Universe. These constraints constitute very conservative estimates on the boost factor for more realistic models where the dark matter particle also couples to quarks and weak gauge bosons, such as the lightest neutralino which we also analyze for some concrete benchmark points. The limits on the astrophysical boost factors presented here could be used to evaluate the prospects to detect a gamma-ray signal from dark matter annihilations at currently operating IACTs as well as in the projected CTA

  8. 《李尔王》:基督教精神的反叛与回归%King Lear:Rebel and Regression of Christian Spirit

    Institute of Scientific and Technical Information of China (English)

    马林贤

    2015-01-01

    In King Lear,humanistic thought and egoistic trend of thoughts coexist,different ideological concepts bringing different codes of conduct. Egoists,in order to pursue their own interests,disregard social morality and religious taboos,abandon ethics,and pursue the satisfaction of desire madly. However,Humanists bond the good and fraternity of Christianity together,and find out a way to cure society. Through their efforts,people start to see the hope of national re-juvenation and ethics rebuilding.%在《李尔王》中,人文主义思想与利己主义思潮同时存在,不同的思想理念带来不同的行为准则。利己主义者为了一己私利,不顾社会道德和宗教禁忌,抛弃纲常伦理,疯狂追求欲望的满足。人文主义者则把善与基督教的博爱结合起来,找到了医治社会的药方。他们的努力使人们看到了国家复兴、伦理道德得以重建的希望。

  9. Ion optics and beam dynamics optimization at the HESR storage ring for the SPARC experiments with highly charged heavy ions

    Energy Technology Data Exchange (ETDEWEB)

    Kovalenko, Oleksandr

    2015-06-24

    The High-Energy Storage Ring (HESR) is a part of an upcoming International Facility for Antiproton and Ion Research (FAIR) at GSI in Darmstadt. A key part of a scientific program, along with antiproton physics, will be physics with highly-charged heavy ions. Phase-space cooled beams together with fixed internal target will provide an excellent environment for storage ring experiments at the HESR for the SPARC collaboration. Until recently, however, the existing ion optical lattice for the HESR was designed only for the experiments with antiproton beams. The thesis presents a new ion optical mode developed specifically for the operation of the HESR with highly charged heavy ions. The presence of the errors, such as beam momentum spread, magnetic field impurities or magnets misalignments, leads to disruption of beam dynamics: exciting of resonant motion and loss of beam stability. Within the paper, these effects are investigated with the help of numerical codes for particle accelerator design and simulation MAD-X and MIRKO. A number of correction techniques are applied to minimize the nonlinear impact on the beam dynamics and improve the experimental conditions. The application of the analytical and numerical tools is demonstrated in the experiment with uranium U{sup 90+} beam at the existing storage ring ESR, GSI.

  10. Ion optics and beam dynamics optimization at the HESR storage ring for the SPARC experiments with highly charged heavy ions

    International Nuclear Information System (INIS)

    The High-Energy Storage Ring (HESR) is a part of an upcoming International Facility for Antiproton and Ion Research (FAIR) at GSI in Darmstadt. A key part of a scientific program, along with antiproton physics, will be physics with highly-charged heavy ions. Phase-space cooled beams together with fixed internal target will provide an excellent environment for storage ring experiments at the HESR for the SPARC collaboration. Until recently, however, the existing ion optical lattice for the HESR was designed only for the experiments with antiproton beams. The thesis presents a new ion optical mode developed specifically for the operation of the HESR with highly charged heavy ions. The presence of the errors, such as beam momentum spread, magnetic field impurities or magnets misalignments, leads to disruption of beam dynamics: exciting of resonant motion and loss of beam stability. Within the paper, these effects are investigated with the help of numerical codes for particle accelerator design and simulation MAD-X and MIRKO. A number of correction techniques are applied to minimize the nonlinear impact on the beam dynamics and improve the experimental conditions. The application of the analytical and numerical tools is demonstrated in the experiment with uranium U90+ beam at the existing storage ring ESR, GSI.

  11. Multiple ionization of He, Ne, and Ar by fast protons and antiprotons

    Energy Technology Data Exchange (ETDEWEB)

    Andersen, L.H.; Hvelplund, P.; Knudsen, H.; Moller, S.P.; Sorensen, A.H.; Elsener, K.; Rensfelt, K.; Uggerhoj, E.

    1987-10-15

    Single and multiple ionization of He, Ne, and Ar has been studied experimentally by impact of fast protons and antiprotons. The single-ionization cross sections obtained with protons and antiprotons are found to be the same. The double-ionization cross sections obtained with antiprotons, however, are much larger than those obtained with protons at equal velocity. This difference is found for all three gases but the effect is largest for He and Ne, where the difference is about a factor of 2 at 1 MeV/amu. The difference is discussed in terms of interference between two collision mechanisms which both result in double-electron escape. Experimental information on the magnitude of the interference term is obtained by inclusion of double-ionization data, partly obtained in this work, for fast electron and ..cap alpha..-particle impact. For triple ionization of Ne, we also find that antiprotons yield much larger cross sections than protons do. Identical cross sections, however, are found for triple ionization of Ar with protons and antiprotons. This is believed to be due to the fact that triple ionization of Ar is mainly a consequence of a single vacancy produced in an inner shell followed by electronic rearrangement. This observation supports the interpretation that the observed charge effect is due to an interference effect in the outermost shell.

  12. Modeling of the Near-Earth Low-Energy Antiproton Fluxes

    Directory of Open Access Journals (Sweden)

    U. B. Jayanthi

    2011-01-01

    Full Text Available The local interstellar antiproton spectrum is simulated taking into account antineutron decay, (He,p interaction, secondary and tertiary antiproton production, and the solar modulation in the “force field” approximation. Inclusive invariant cross-sections were obtained through a Monte Carlo procedure using the Multistage Dynamical Model code simulating various processes of the particle production. The results of the simulations provided flux values of 4⋅10−3 to 10−2 and 10−2 to 1.7⋅10−2 antiprotons/(2 s sr GeV at energies of 0.2 and 1 GeV, respectively, for the solar maximum and minimum epochs. Simulated flux of the trapped antiprotons in the inner magnetosphere due to galactic cosmic ray (GCR interactions with the atmospheric constituents exceeds the galactic antiproton flux up to several orders. These simulation results considering the assumptions with the attendant limitations are in comprehensive agreement with the experimental data including the PAMELA ones.

  13. Direct detection of antiprotons with the Timepix3 in a new electrostatic selection beamline

    Science.gov (United States)

    Pacifico, N.; Aghion, S.; Alozy, J.; Amsler, C.; Ariga, A.; Ariga, T.; Bonomi, G.; Bräunig, P.; Bremer, J.; Brusa, R. S.; Cabaret, L.; Caccia, M.; Campbell, M.; Caravita, R.; Castelli, F.; Cerchiari, G.; Chlouba, K.; Cialdi, S.; Comparat, D.; Consolati, G.; Demetrio, A.; Di Noto, L.; Doser, M.; Dudarev, A.; Ereditato, A.; Evans, C.; Ferragut, R.; Fesel, J.; Fontana, A.; Gerber, S.; Giammarchi, M.; Gligorova, A.; Guatieri, F.; Haider, S.; Holmestad, H.; Huse, T.; Jordan, E.; Kellerbauer, A.; Kimura, M.; Krasnický, D.; Lagomarsino, V.; Lansonneur, P.; Lawler, G.; Lebrun, P.; Llopart, X.; Malbrunot, C.; Mariazzi, S.; Marx, L.; Matveev, V.; Mazzotta, Z.; Nebbia, G.; Nedelec, P.; Oberthaler, M.; Pagano, D.; Penasa, L.; Petracek, V.; Pistillo, C.; Prelz, F.; Prevedelli, M.; Ravelli, L.; Resch, L.; Røhne, O. M.; Rotondi, A.; Sacerdoti, M.; Sandaker, H.; Santoro, R.; Scampoli, P.; Smestad, L.; Sorrentino, F.; Spacek, M.; Storey, J.; Strojek, I. M.; Testera, G.; Tietje, I.; Tlustos, L.; Widmann, E.; Yzombard, P.; Zavatarelli, S.; Zmeskal, J.; Zurlo, N.

    2016-09-01

    We present here the first results obtained employing the Timepix3 for the detection and tagging of annihilations of low energy antiprotons. The Timepix3 is a recently developed hybrid pixel detector with advanced Time-of-Arrival and Time-over-Threshold capabilities and has the potential of allowing precise kinetic energy measurements of low energy charged particles from their time of flight. The tagging of the characteristic antiproton annihilation signature, already studied by our group, is enabled by the high spatial and energy resolution of this detector. In this study we have used a new, dedicated, energy selection beamline (GRACE). The line is symbiotic to the AEgIS experiment at the CERN Antiproton Decelerator and is dedicated to detector tests and possibly antiproton physics experiments. We show how the high resolution of the Timepix3 on the Time-of-Arrival and Time-over-Threshold information allows for a precise 3D reconstruction of the annihilation prongs. The presented results point at the potential use of the Timepix3 in antimatter-research experiments where a precise and unambiguous tagging of antiproton annihilations is required.

  14. Antiproton Production in 11.5 A GeV/c Au+Pb Nucleus-Nucleus Collisions

    OpenAIRE

    E687 Collaboration; al, T. A. Armstrong et

    1997-01-01

    We present the first results from the E864 collaboration on the production of antiprotons in 10% central 11.5 A GeV/c Au+Pb nucleus collisions at the Brookhaven AGS. We report invariant multiplicities for antiproton production in the kinematic region 1.4

  15. Alternative loop rings

    CERN Document Server

    Goodaire, EG; Polcino Milies, C

    1996-01-01

    For the past ten years, alternative loop rings have intrigued mathematicians from a wide cross-section of modern algebra. As a consequence, the theory of alternative loop rings has grown tremendously. One of the main developments is the complete characterization of loops which have an alternative but not associative, loop ring. Furthermore, there is a very close relationship between the algebraic structures of loop rings and of group rings over 2-groups. Another major topic of research is the study of the unit loop of the integral loop ring. Here the interaction between loop rings and group ri

  16. Measurements of Electron Spectra in the Forward Direction in Slow-Antiproton Carbon-Foil Collisions

    Science.gov (United States)

    Yamazaki, Yasunori; Kuroki, Kenro; Komaki, Ken-Ichiro; Andersen, Lars H.; Horsdal-Pedersen, Erik; Hvelplund, Preben; Knudsen, Helge; M{ø}ller, S{ø}ren P.; Uggerh{ø}j, Erik; Elsener, Konrad

    1990-08-01

    The spectrta of electrons emitted in the forward direction from antiproton and proton bombardments on carbon foils have been studied for projectile energies from 500 to 750 keV. Our main observation is that at the electron energy where the well-known convoy peak is observed for proton impact, the spectrum for equivelocity antiprotons is smooth, showing no indication of a deep anticusp. However, around 50 eV below the electron energy where the cusp is observed for proton impact, we have observed a small peak for antiproton impact. The energy and the relative intensity of the bump are found to be consistent with those predicted for electrons released from a wake-riding state.

  17. A fussy revisitation of antiprotons as a tool for Dark Matter searches

    CERN Document Server

    Boudaud, Mathieu

    2015-01-01

    Antiprotons are regarded as a powerful probe for Dark Matter (DM) indirect detection and indeed current data from \\PAMELA\\ have been shown to lead to stringent constraints. However, in order to exploit their constraining/discovery power properly, great attention must be put into effects (linked to their propagation in the Galaxy) which may be perceived as subleading but actually prove to be quite relevant. We revisit the computation of the astrophysical background and of the DM antiproton fluxes fully including the effects of: diffusive reacceleration, energy losses including tertiary component and solar modulation (in a force field approximation). Using the updated proton and helium fluxes just released by the \\AMS\\ experiment we reevaluate the secondary astrophysical antiproton to proton ratio and its uncertainties, and compare it with the ratio preliminarly reported by \\AMS. We find no unambiguous evidence for a significant excess with respect to expectations. Yet, some preference for a flatter energy depe...

  18. Measurements of electron spectra in the forward direction in slow-antiproton carbon-foil collisions

    International Nuclear Information System (INIS)

    The spectra of electrons emitted in the forward direction from antiproton and proton bombardments on carbon foils have been studied for projectile energies from 500 to 750 keV. Our main observation is that at the electron energy where the well-known convoy peak is observed for proton impact, the spectrum for equivelocity antiprotons is smooth, showing no indication of a deep anticusp. However, around 50 eV below the electron energy where the cusp is observed for proton impact, we have observed a small peak for antiproton impact. The energy and the relative intensity of the bump are found to be consistent with those predicted for electrons released from a wakeriding state. (author)

  19. Antiproton signatures from astrophysical and dark matter sources at the galactic center

    CERN Document Server

    Cembranos, J A R; Maroto, A L

    2015-01-01

    The center of our Galaxy is a complex region characterized by extreme phenomena. The presence of the supermassive Sagittarius A* black hole, a high Dark Matter density and an even higher baryonic density are able to produce very energetic processes. Indeed, high energetic gamma rays have been observed by different telescopes, although its origin is not clear. In this work, we constrain the possible antiproton flux component associated to this signal. The expected secondary astrophysical antiproton background already saturates the observed data. It implies that any other important astrophysical source leads to an inconsistent excess, since the theoretical uncertainties corresponding to the mentioned background are small. The constraints depend on the diffusion model and the spectral features of the source. In particular, we consider antiproton spectra described by a power-law, a monochromatic signal and a Standard Model particle-antiparticle channel production.

  20. Heating due to momentum transfer in low-energy positronium-antiproton scattering

    Science.gov (United States)

    Charlton, M.; Kadyrov, A. S.; Bray, I.

    2016-09-01

    We investigate the consequences of unexpectedly large elastic cross sections for the scattering of low-energy antiprotons from n ≤3 positronium (Ps) on the experimental implementation of antihydrogen formation via Ps-antiproton collisions. The integrated elastic cross sections, obtained using the two-center convergent close-coupling theory, can be up to three orders of magnitude greater than their counterparts for antihydrogen formation. The differential momentum transfer cross sections, which suppress the large cross sections at forward scattering angles, show remarkably rich behavior across all scattering angles. We discuss the implications of these findings for the heating, via momentum transfer, of clouds of trapped antiprotons that are typically used for the creation of antihydrogen.

  1. The experiment PANDA: physics with antiprotons at FAIR

    Science.gov (United States)

    Boca, Gianluigi

    2015-05-01

    PANDA is an experiment that will run at the future facility FAIR, Darmstadt, Germany. A high intensity and cooled antiproton beam will collide on a fixed hydrogen or nuclear target covering center-of-mass energies between 2.2 and 5.5 GeV. PANDA addresses various physics aspects from the low energy non-perturbative region towards the perturbative regime of QCD. With the impressive theoretical developments in this field, e.g. lattice QCD, the predictions are becoming more accurate in the course of time. The data harvest with PANDA will, therefore, be an ideal test bench with the aim to provide a deeper understanding of hadronic phenomena such as confinement and the generation of hadron masses. A variety of physics topics will be covered with PANDA, for example: the formation or production of exotic non-qqbar charm meson states connected to the recently observed XYZ spectrum; the study of gluon-rich matter, such as glueballs and hybrids; the spectroscopy of the excited states of strange and charm baryons, their production cross section and their spin correlations; the behaviour of hadrons in nuclear matter; the hypernuclear physics; the electromagnetic proton form factors in the timelike region. The PANDA experiment is designed to achieve the above mentioned physics goals with a setup with the following characteristics: an almost full solid angle acceptance; excellent tracking capabilities with high resolution (1-2 % at 1 GeV/c in the central region); secondary vertex detection with resolution ≈ 100 microns or better; electromagnetic calorimetry for detections of gammas and electrons up to 10 GeV; good particle identification of charge tracks (electrons, muons, pions, kaons, protons); a dedicated interchangeable central apparatus for the hypernuclear physics; detector and data acquisition system capable of working at 20 MHz interaction rate with an intelligent software trigger that can provide maximum flexibility.

  2. Analysis of Subthreshold Antiproton Production in p-Nucleus and Nucleus-Nucleus Collisions in the RBUU Approach

    CERN Document Server

    Teis, S; Maruyama, T; Mosel, U; Teis, Stefan; Cassing, Wolfgang; Maruyama, Tomoyuki; Mosel, Ulrich

    1994-01-01

    We calculate the subthreshold production of antiprotons in the Lorentz-covariant RBUU approach employing a weighted testparticle method to treat the antiproton propagation and absorption nonperturbatively. We find that the pbar differential cross sections are highly sensitive to the baryon and antiproton selfenergies in the dense baryonic environment. Adopting the baryon scalar and vector selfenergies from the empirical optical potential for proton-nucleus elastic scattering and from Dirac-Brueckner calculations at higher density rho > rho_0 we examine the differential pbar spectra as a function of the antiproton selfenergy. A detailed comparison with the available experimental data for p-nucleus and nucleus-nucleus reactions shows that the antiproton feels a moderately attractive mean-field at normal nuclear matter density rho_0 which is in line with a dispersive potential extracted from the free annihilation cross section.

  3. Single ionization of helium by 40--3000-keV antiprotons

    Energy Technology Data Exchange (ETDEWEB)

    Andersen, L.H.; Hvelplund, P.; Knudsen, H.; Moller, S.P.; Pedersen, J.O.P.; Tang-Petersen, S.; Uggerhoj, E. (Institute of Physics, University of Aarhus, DK-8000 Aarhus C (Denmark)); Elsener, K. (CERN, CH-1211 Geneva (Switzerland)); Morenzoni, E. (PSI, CH-5234 Villigen (Switzerland))

    1990-06-01

    Measurements of single-ionization cross sections for antiproton impact on helium atoms are reported for impact energies ranging from 40 keV to 3 MeV. It is found that the measured cross sections are in good agreement with recent theoretical estimates based on the continuum-distorted-wave approximation. From a comparison with similar proton data, the ratio between antiproton and proton results is obtained. The energy dependence of this ratio is compared with various theoretical estimates and explained as a result of polarization and binding effects.

  4. Single ionization of helium by 40-3000-keV antiprotons

    Science.gov (United States)

    Andersen, L. H.; Hvelplund, P.; Knudsen, H.; Møller, S. P.; Pedersen, J. O. P.; Tang-Petersen, S.; Uggerhøj, E.; Elsener, K.; Morenzoni, E.

    1990-06-01

    Measurements of single-ionization cross sections for antiproton impact on helium atoms are reported for impact energies ranging from 40 keV to 3 MeV. It is found that the measured cross sections are in good agreement with recent theoretical estimates based on the continuum-distorted-wave approximation. From a comparison with similar proton data, the ratio between antiproton and proton results is obtained. The energy dependence of this ratio is compared with various theoretical estimates and explained as a result of polarization and binding effects.

  5. Operating Procedure Changes to Improve Antiproton Production at the Fermilab Tevatron Collider

    Energy Technology Data Exchange (ETDEWEB)

    Drendel, B.; Morgan, J.P.; Vander Meulen, D.; /Fermilab

    2009-04-01

    Since the start of Fermilab Collider Run II in 2001, the maximum weekly antiproton accumulation rate has increased from 400 x 10{sup 10} Pbars/week to approximately 3,700 x 10{sup 10} Pbars/week. There are many factors contributing to this increase, one of which involves changes to operational procedures that have streamlined and automated Antiproton Source production. Automation has been added to the beam line orbit control, stochastic cooling power level management, and RF settings. In addition, daily tuning efforts have been streamlined by implementing sequencer driven tuning software.

  6. Longitudinal momentum mining of antiprotons at the Fermilab Recycler: past, present and future

    Energy Technology Data Exchange (ETDEWEB)

    Bhat, C.M.; Chase, B.E.; Gattuso, C.; Joireman, P.W.; /Fermilab

    2007-06-01

    The technique of longitudinal momentum mining (LMM)[1] in the Fermilab Recycler was adopted in early 2005 to extract thirty-six equal intensity and equal 6D-emittance antiproton bunches for proton-antiproton collider operation in the Tevatron. Since that time, several improvements have been made in the Recycler and the mining technique to handle higher intensity beams. Consequently, the Recycler has become a key contributor to the increased luminosity performance observed during Tevatron Run IIb. In this paper, we present an overview of the improvements and the current status of the momentum mining technique.

  7. Centrifugal separation and equilibration dynamics in an electron-antiproton plasma

    CERN Document Server

    Andresen, G B; Baquero-Ruiz, Marcelo; Bertsche, William; Bowe, Paul D; Butler, Eoin; Cesar, Claudio L; Chapman, Steven; Charlton, Michael; Deller, A; Eriksson, S; Fajans, Joel; Friesen, Tim; Fujiwara, Makoto C; Gill, David R; Gutierrez, A; Hangst, Jeffrey S; Hardy, Walter N; Hayden, Michael E; Humphries, Andrew J; Hydomako, Richard; Jonsell, Svante; Madsen, Niels; Menary, Scott; Nolan, Paul; Olin, Art; Povilus, Alexander; Pusa, Petteri; Robicheaux, Francis; Sarid, Eli; Silveira, Daniel M; So, Chukman; Storey, James W; Thompson, Robert I; van der Werf, Dirk P; Wurtele, Jonathan S; Yamazaki, Yasunori

    2011-01-01

    Charges in cold, multiple-species, non-neutral plasmas separate radially by mass, forming centrifugally-separated states. Here, we report the first detailed measurements of such states in an electron-antiproton plasma, and the first observations of the separation dynamics in any centrifugally-separated system. While the observed equilibrium states are expected and in agreement with theory, the equilibration time is approximately constant over a wide range of parameters, a surprising and as yet unexplained result. Electron-antiproton plasmas play a crucial role in antihydrogen trapping experiments.

  8. Pion, Kaon, Proton and Antiproton Production in Proton-Proton Collisions

    Science.gov (United States)

    Norbury, John W.; Blattnig, Steve R.

    2008-01-01

    Inclusive pion, kaon, proton, and antiproton production from proton-proton collisions is studied at a variety of proton energies. Various available parameterizations of Lorentz-invariant differential cross sections as a function of transverse momentum and rapidity are compared with experimental data. The Badhwar and Alper parameterizations are moderately satisfactory for charged pion production. The Badhwar parameterization provides the best fit for charged kaon production. For proton production, the Alper parameterization is best, and for antiproton production the Carey parameterization works best. However, no parameterization is able to fully account for all the data.

  9. First measurement of the antiproton-nucleus annihilation cross section at 125 keV

    Energy Technology Data Exchange (ETDEWEB)

    Aghai-Khozani, H. [Max-Planck-Institut fur Quantenoptik (Germany); Barna, D. [CERN (Switzerland); Corradini, M. [Università degli Studi di Brescia, Dipartimento di Ingegneria dell’Informazione (Italy); Salvador, D. De [Università di Padova, Dipartimento di Fisica e Astronomia (Italy); Hayano, R. [University of Tokyo, Department of Physics (Japan); Hori, M. [Max-Planck-Institut fur Quantenoptik (Germany); Kobayashi, T. [University of Tokyo, Department of Physics (Japan); Leali, M.; Lodi-Rizzini, E.; Mascagna, V. [Università degli Studi di Brescia, Dipartimento di Ingegneria dell’Informazione (Italy); Prest, M. [Università degli Studi dell’Insubria, Dipartimento di Scienza e Alta Tecnologia (Italy); Seiler, D. [TUM Department of Physics E12 (Germany); Soter, A. [Max-Planck-Institut fur Quantenoptik (Germany); Todoroki, K. [University of Tokyo, Department of Physics (Japan); Vallazza, E. [Istituto Nazionale di Fisica Nucleare, Sezione di Trieste (Italy); Venturelli, L., E-mail: venturelli@bs.infn.it [Università degli Studi di Brescia, Dipartimento di Ingegneria dell’Informazione (Italy)

    2015-08-15

    The first observation of in-flight antiproton-nucleus annihilation at ∼130 keV obtained with the ASACUSA detector has demonstrated that the measurement of the cross section of the process is feasible at such extremely low energies Aghai-Khozani, H., et al., Eur. Phys. J. Plus 127, 55 (2012). Here we present the results of the data analysis with the evaluations of the antiproton annihilation cross sections on carbon, palladium and platinum targets at ∼125 keV.

  10. Collisions of low-energy antiprotons with molecular hydrogen: ionization, excitation and stopping power

    DEFF Research Database (Denmark)

    Lühr, Armin Christian; Saenz, Alejandro

    2009-01-01

    A time-dependent coupled-channel approach was used to calculate ionization, excitation, and energy-loss cross sections as well as energy spectra for antiproton and proton collisions with molecular hydrogen for impact energies 8 < E < 4000 keV.......A time-dependent coupled-channel approach was used to calculate ionization, excitation, and energy-loss cross sections as well as energy spectra for antiproton and proton collisions with molecular hydrogen for impact energies 8 < E < 4000 keV....

  11. Depth-Dose and LET Distributions of Antiproton Beams in Various Target Materials

    DEFF Research Database (Denmark)

    Herrmann, Rochus; Olsen, Sune; Petersen, Jørgen B.B.;

    Purpose  Radiotherapy with antiprotons is still being investigated as a possible new beam modality. Antiprotons behave much like protons until they come to rest, where they will annihilate with a target nucleus, thereby releasing additional energy. This can potentially lead to a favourable  depth...... of elements with higher Z, may lead to heavier fragments, which in turn may increase the LET and be beneficial in radiotherapy context. Also, it was speculated whether the addition of elements with high thermal neutron cross section to the target material may or may not boost the locally deposited energy from...

  12. Antiproton and proton collisions with the alkali-metal atoms Li, Na, and K

    DEFF Research Database (Denmark)

    Lühr, Armin Christian; Saenz, Alejandro

    2008-01-01

    Single-electron ionization and excitation cross sections as well as cross sections for excitation into the first excited p state of the alkali-metal atoms Li(2s), Na(3s), and K(4s) colliding with antiprotons and protons were calculated using a time-dependent channel-coupling approach. For antipro......Single-electron ionization and excitation cross sections as well as cross sections for excitation into the first excited p state of the alkali-metal atoms Li(2s), Na(3s), and K(4s) colliding with antiprotons and protons were calculated using a time-dependent channel-coupling approach...

  13. The ratio Ri for nondissociative ionization of molecular hydrogen by antiproton/proton impact

    International Nuclear Information System (INIS)

    The theoretical ratio Ri of antiproton/proton cross sections for nondissociative ionization of hydrogen molecule has been obtained as a function of the impact energy E in the range 30 ≤ E ≤ 2500 keV lab. The required cross sections were computed in the close-coupling formulation of the semiclassical impact parameter theory using a simple one-active electron model for the molecular target. The ratio Ri is important for the analysis of the recent experimental data of Andersen et al. on antiproton scattering and the understanding of the collisional mechanisms in the keV range. (orig.)

  14. Observation of antiproton annihilation in heavy nuclei at 100 GeV/c

    International Nuclear Information System (INIS)

    We report on the observation of antiproton annihilation in Mg, Ag, and Au nuclei at 100 GeV/c. The experiment was performed with the Fermilab 30'' bubble chamber spectrometer and associated Downstream Particle Identifiers. By identifying events without a leading anti p or anti n we have determined that (39+-6)% of the antiprotons annihilate in a heavy nucleus. We present this fraction as a function of atomic mass number and discuss the associated charged particle multiplicity. 5 refs., 3 figs

  15. On JB-Rings

    Institute of Scientific and Technical Information of China (English)

    Huanyin CHEN

    2007-01-01

    A ring R is a QB-ring provided that aR + bR = R with a, b ∈ R implies that there exists a y ∈ R such that a+by ∈ R-1q. It is said that a ring R is a JB-ring provided that R/J(R) is a QB-ring, where J(R) is the Jacobson radical of R. In this paper, various necessary and sufficient conditions, under which a ring is a JB-ring, are established. It is proved that JB-rings can be characterized by pseudo-similarity. Furthermore, the author proves that R is a J B-ring iff so is R/J(R)2.

  16. New dust belts of Uranus: one ring, two ring, red ring, blue ring.

    Science.gov (United States)

    de Pater, Imke; Hammel, Heidi B; Gibbard, Seran G; Showalter, Mark R

    2006-04-01

    We compared near-infrared observations of the recently discovered outer rings of Uranus with Hubble Space Telescope results. We find that the inner ring, R/2003 U 2, is red, whereas the outer ring, R/2003 U 1, is very blue. Blue is an unusual color for rings; Saturn's enigmatic E ring is the only other known example. By analogy to the E ring, R/2003 U 1 is probably produced by impacts into the embedded moon Mab, which apparently orbits at a location where nongravitational perturbations favor the survival and spreading of submicron-sized dust. R/2003 U 2 more closely resembles Saturn's G ring, which is red, a typical color for dusty rings. PMID:16601188

  17. A new method to measure the gravitational acceleration of the antiproton at very low energies

    International Nuclear Information System (INIS)

    A new possible method to measure in lab the gravitational acceleration ''g'' of the antiproton is presented assuming that very low energy particles can be used. A schematic lay-out is described and preliminary results on ''g'' obtained by a simple simulation are given. The features of the method and its possible experimental problems are discussed

  18. Closing in on mass-degenerate dark matter scenarios with antiprotons and direct detection

    Energy Technology Data Exchange (ETDEWEB)

    Garny, Mathias [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Ibarra, Alejandro; Pato, Miguel; Vogl, Stefan [Technische Univ. Muenchen, Garching (Germany). Physik-Department

    2012-07-15

    Over the last years both cosmic-ray antiproton measurements and direct dark matter searches have proved particularly effective in constraining the nature of dark matter candidates. The present work focusses on these two types of constraints in a minimal framework which features a Majorana fermion as the dark matter particle and a scalar that mediates the coupling to quarks. Considering a wide range of coupling schemes, we derive antiproton and direct detection constraints using the latest data and paying close attention to astrophysical and nuclear uncertainties. Both signals are strongly enhanced in the presence of degenerate dark matter and scalar masses, but we show that the effect is especially dramatic in direct detection. Accordingly, the latest direct detection limits take the lead over antiprotons. We find that antiproton and direct detection data set stringent lower limits on the mass splitting, reaching 19% at a 300 GeV dark matter mass for a unity coupling. Interestingly, these limits are orthogonal to ongoing collider searches at the Large Hadron Collider, making it feasible to close in on degenerate dark matter scenarios within the next years.

  19. Antiproton signatures from astrophysical and dark matter sources at the galactic center

    Science.gov (United States)

    Cembranos, J. A. R.; Gammaldi, V.; Maroto, A. L.

    2015-03-01

    The center of our Galaxy is a complex region characterized by extreme phenomena. The presence of the supermassive Sagittarius A* black hole, a high dark matter density and an even higher baryonic density are able to produce very energetic processes. Indeed, high energetic gamma-rays have been observed by different telescopes, although their origin is not clear. In this work, we estimate the possible antiproton flux component associated with this signal. The expected secondary astrophysical antiproton background already saturates the observed data. It implies that any other important astrophysical source leads to an inconsistent excess. We estimate the sensitivity of PAMELA to this new primary antiproton source, which depends on the diffusion model and its spectral features. In particular, we consider antiproton spectra described by a power-law, a monochromatic signal and a Standard Model particle-antiparticle channel production. This latter spectrum is typical in the production from annihilating or decaying dark matter. We pay particular attention to the case of a heavy dark matter candidate, which could be associated with the High Energy Stereoscopic System (HESS) data observed from the J1745-290 source.

  20. Antiproton-to-proton ratios for ALICE heavy-ion collisions

    Energy Technology Data Exchange (ETDEWEB)

    Tawfik, A., E-mail: atawfik@cern.ch [Egyptian Center for Theoretical Physics (ECTP), MTI University, Cairo (Egypt)

    2011-06-01

    Assuming that the final state of hadronization takes place along the freezeout line, which is defined by a constant entropy density, the antiproton-to-proton ratios produced in heavy-ion collisions are studied in framework of the hadron resonance gas (HRG) model. A phase transition from quark-gluon plasma to hadrons, a hadronization, has been conjectured in order to allow modifications in the phase-space volume and thus in the single-particle distribution function. Implementing both modifications in the grand-canonical partition function and taking into account the experimental acceptance in the heavy-ion collisions, the antiproton-to-proton ratios over center-of-mass energies {radical}(s) ranging from AGS to RHIC are very well reproduced by the HRG model. Comparing with the same particle ratios in pp collisions results in a gradually narrowing discrepancy with increasing {radical}(s). At LHC energy, the ALICE antiproton-to-proton ratios in the pp collisions turn to be very well described by the HRG model as well. It is likely that the ALICE AA-program will produce the same antiproton-to-proton ratios as the pp-one. Furthermore, the ratio gets very close to unity indicating that the matter-antimatter asymmetry nearly vanishes. The chemical potential calculated at this energy strengthens the assumption of almost fully matter-antimatter symmetry up to the LHC energy.

  1. Properties of Antiprotons and Antihydrogen, and the Study of Exotic Atoms

    CERN Document Server

    Doser, Michael

    2015-01-01

    The study of exotic atoms, of antiprotons and of antihydrogen atoms provides many windows into the investigation of fundamental symmetries, of interactions between particles and nuclei, of nuclear physics and of atomic physics. This field appeared at CERN simultaneously with the first accelerators, and has advanced over the decades in parallel with improvements and advances in its infrastructure.

  2. Experimental setup and first measurement of DNA damage induced along and around an antiproton beam

    DEFF Research Database (Denmark)

    Kavanagh, J. N.; Currell, F. J.; Timson, D. J.;

    2010-01-01

    Radiotherapy employs ionizing radiation to induce lethal DNA lesions in cancer cells while minimizing damage to healthy tissues. Due to their pattern of energy deposition, better therapeutic outcomes can, in theory, be achieved with ions compared to photons. Antiprotons have been proposed to offer...

  3. Status Report for Experiment AD-4/ACE Biological Effectiveness of Antiproton Annihilation

    CERN Document Server

    Holzscheiter, M H; Angelopoulos, Angelo; Bassler, Niels; Beyer, Gerd; Currell, Fred; De Marco, John; Doser, Michael; Hajdukovic, Dragan; Hartley, Oliver; Kavanagh, Joy; Iwamoto, Kei; Jäkel, Oliver; Kantemiris, Ioannis; Knudsen, Helge; Kovacevic, Sandra; McBride, Bill; Møller, Søren Pape; Overgaard, Jens; Petersen, Jørgen; Ratib, Osman; Schettino, Giuseppe; Timson, David; Singers-Sørensen, Brita; Solberg, Timothy; Vranjes, Sanja; Wouters, Brad

    2009-01-01

    Status report for experiment AD-4/ACE showing recent progress in RBE measurements for V79 Chinese Hamster cells irradiated with antiprotons. Also discussed are initial test experiments using the H2AX assay to study DNA damage to cells and initial experiments using liquid ionization chambers.

  4. Groups, rings, modules

    CERN Document Server

    Auslander, Maurice

    2014-01-01

    This classic monograph is geared toward advanced undergraduates and graduate students. The treatment presupposes some familiarity with sets, groups, rings, and vector spaces. The four-part approach begins with examinations of sets and maps, monoids and groups, categories, and rings. The second part explores unique factorization domains, general module theory, semisimple rings and modules, and Artinian rings. Part three's topics include localization and tensor products, principal ideal domains, and applications of fundamental theorem. The fourth and final part covers algebraic field extensions

  5. Muon storage ring

    CERN Multimedia

    1974-01-01

    The muon storage ring where the g-2 of the muon is being measured with extremely high accuracy. The ring is 14-m in diameter and has very precise magnetic bending and electric focussing fields so that the muons orbit the ring under well-defined conditions.

  6. Rings Around Uranus

    Science.gov (United States)

    Maran, Stephen P.

    1977-01-01

    Events leading up to the discovery of the rings of Uranus are described. The methods used and the logic behind the methods are explained. Data collected to prove the existence of the rings are outlined and theories concerning the presence of planetary rings are presented. (AJ)

  7. Antiproton annihilation physics in the Monte Carlo particle transport code SHIELD-HIT12A

    Energy Technology Data Exchange (ETDEWEB)

    Taasti, Vicki Trier; Knudsen, Helge [Dept. of Physics and Astronomy, Aarhus University (Denmark); Holzscheiter, Michael H. [Dept. of Physics and Astronomy, Aarhus University (Denmark); Dept. of Physics and Astronomy, University of New Mexico (United States); Sobolevsky, Nikolai [Institute for Nuclear Research of the Russian Academy of Sciences (INR), Moscow (Russian Federation); Moscow Institute of Physics and Technology (MIPT), Dolgoprudny (Russian Federation); Thomsen, Bjarne [Dept. of Physics and Astronomy, Aarhus University (Denmark); Bassler, Niels, E-mail: bassler@phys.au.dk [Dept. of Physics and Astronomy, Aarhus University (Denmark)

    2015-03-15

    The Monte Carlo particle transport code SHIELD-HIT12A is designed to simulate therapeutic beams for cancer radiotherapy with fast ions. SHIELD-HIT12A allows creation of antiproton beam kernels for the treatment planning system TRiP98, but first it must be benchmarked against experimental data. An experimental depth dose curve obtained by the AD-4/ACE collaboration was compared with an earlier version of SHIELD-HIT, but since then inelastic annihilation cross sections for antiprotons have been updated and a more detailed geometric model of the AD-4/ACE experiment was applied. Furthermore, the Fermi–Teller Z-law, which is implemented by default in SHIELD-HIT12A has been shown not to be a good approximation for the capture probability of negative projectiles by nuclei. We investigate other theories which have been developed, and give a better agreement with experimental findings. The consequence of these updates is tested by comparing simulated data with the antiproton depth dose curve in water. It is found that the implementation of these new capture probabilities results in an overestimation of the depth dose curve in the Bragg peak. This can be mitigated by scaling the antiproton collision cross sections, which restores the agreement, but some small deviations still remain. Best agreement is achieved by using the most recent antiproton collision cross sections and the Fermi–Teller Z-law, even if experimental data conclude that the Z-law is inadequately describing annihilation on compounds. We conclude that more experimental cross section data are needed in the lower energy range in order to resolve this contradiction, ideally combined with more rigorous models for annihilation on compounds.

  8. Study of the anti-hydrogen atom and ion formation in the collisions antiproton-positronium

    International Nuclear Information System (INIS)

    The future CERN experiment called GBAR intends to measure the gravitational acceleration of antimatter on Earth using cold (neV) anti-hydrogen atoms undergoing a free fall. The experiment scheme first needs to cool anti-hydrogen positive ions, obtained thanks to two consecutive reactions occurring when an antiproton beam collides with a dense positronium cloud.The present thesis studies these two reactions in order to optimise the production of the anti-ions. The total cross sections of both reactions have been computed in the framework of a perturbation theory model (Continuum Distorted Wave - Final State), in the range 0 to 30 keV antiproton kinetic energy; several excited states of positronium have been investigated. These cross sections have then been integrated to a simulation of the interaction zone where antiprotons collide with positronium; the aim is to find the optimal experimental parameters for GBAR. The results suggest that the 2P, 3D or, to a lower extend, 1S states of positronium should be used, respectively with 2, less than 1 or 6 keV antiprotons. The importance of using short pulses of antiprotons has been underlined; the positronium will have to be confined in a tube of 20 mm length and 1 mm diameter. In the prospect of exciting the 1S-3D two-photon transition in positronium at 410 nm, a pulsed laser system had already been designed. It consists in the frequency doubling of an 820 nm pulsed titanium-sapphire laser. The last part of the thesis has been dedicated to the realisation of this laser system, which delivers short pulses (9 ns) of 4 mJ energy at 820 nm. (author)

  9. On Antiproton Production in 158 GeV/c Proton-Carbon Collisions and Nuclear Temperature of Interacting System

    Directory of Open Access Journals (Sweden)

    Fu-Hu Liu

    2013-01-01

    Full Text Available The multisource thermal model is used in this paper to analyze the antiproton (p¯ production process in high-energy proton-carbon (p-C collisions. The transverse momentum, Feynman variable, and rapidity distributions of antiprotons in the nucleon-nucleon center-of-mass system are calculated by using the model. The modeling results are compared and found to be in agreement with the experimental data measured by the NA49 Collaboration at 158 GeV/c beam momentum. As a parameter, the nuclear temperature of interacting system extracted from the antiproton spectrum is estimated to be about 150 MeV.

  10. Skew polynomial rings over abelian and idempotent reflexive rings

    OpenAIRE

    Louzari, Mohamed

    2015-01-01

    Let $R$ be a ring and $\\sigma$ an endomorphism of $R$. In this note, we study skew polynomial rings and skew power series rings over idempotent reflexive rings and abelian rings. Also, we introduce the concept of right (resp., left) $\\sigma$-idempotent reflexive rings which generalizes right (resp., left) idempotent reflexive rings and $\\sigma$-abelian rings. Certain results are obtained as corollaries from our results.

  11. Envelopes of Commutative Rings

    Institute of Scientific and Technical Information of China (English)

    Rafael PARRA; Manuel SAOR(I)N

    2012-01-01

    Given a significative class F of commutative rings,we study the precise conditions under which a commutative ring R has an F-envelope.A full answer is obtained when.F is the class of fields,semisimple commutative rings or integral domains.When F is the class of Noetherian rings,we give a full answer when the Krull dimension of R is zero and when the envelope is required to be epimorphic.The general problem is reduced to identifying the class of non-Noetherian rings having a monomorphic Noetherian envelope,which we conjecture is the empty class.

  12. Physics of quantum rings

    CERN Document Server

    Fomin, Vladimir M

    2013-01-01

    This book deals with a new class of materials, quantum rings. Innovative recent advances in experimental and theoretical physics of quantum rings are based on the most advanced state-of-the-art fabrication and characterization techniques as well as theoretical methods. The experimental efforts allow to obtain a new class of semiconductor quantum rings formed by capping self-organized quantum dots grown by molecular beam epitaxy. Novel optical and magnetic properties of quantum rings are associated with non-trivial topologies at the nanoscale. An adequate characterization of quantum rings is po

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

    Indian Academy of Sciences (India)

    James Ritman

    2006-05-01

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

  14. New Dust Belts of Uranus: One Ring, Two Ring, Red Ring, Blue Ring

    Energy Technology Data Exchange (ETDEWEB)

    de Pater, I; Hammel, H B; Gibbard, S G; Showalter, M R

    2006-02-02

    We compare near-infrared observations of the recently discovered outer rings of Uranus with HST results. We find that the inner ring, R/2003 U 2, is red, whereas the outer ring, R/2003 U 1, is very blue. Blue is an unusual color for rings; Saturn's enigmatic E ring is the only other known example. By analogy to the E ring, R/2003 U 1 is probably produced via impacts into the embedded moon Mab, which apparently orbits at a location where non-gravitational perturbations favor the survival and spreading of sub-micron sized dust. R/2003 U 2 more closely resembles Saturn's G ring.

  15. 《李尔王》中父子冲突的伦理法则%Ethical Rules in the Father-son Conflict in King Lear

    Institute of Scientific and Technical Information of China (English)

    张松林

    2016-01-01

    戏剧《李尔王》中的父子冲突体现了多重伦理原则。首先,父子冲突体现了社会伦理的演变,父权传统遭到了新思想的挑战,子辈中出现了敢于反抗父权的叛逆者,他们不择手段化解父权带来的焦虑和威胁,并最终在冲突中胜出。其次,父子冲突中对自然法则的崇拜破坏了人类社会文明,力量至上的丛林法则让传统道德伦理蒙羞,使其成为不堪一击的社会稳定遮羞布。从美学原则上看,善恶冲突具有使善者价值更为璀璨的作用,文学往往通过恶来衬托善,并通过恶带来的恶果来反思社会伦理的作用。%The father-son conflict in the play King Lear embodies multiple ethical principles .First, the conflict reflects the evolution of social ethics and the traditional patriarchy was challenged by new ideas .The young gen-eration appeared bold enough to rebel against patriarchy .They did anything to resolve anxiety and threats coming from patriarchy and eventually became the winner of the conflict .Secondly , the conflict shows worship for laws of nature which destroyed the civilization of human society .From aesthetic principles , the conflict between good and evil highlights good .So literature tends to zoom good in the background of evil and reflect social ethics through negative consequences brought by evil .

  16. On Exchange QB∞-Rings

    Institute of Scientific and Technical Information of China (English)

    Huanyin Chen

    2007-01-01

    In this paper, we introduce a new class of rings, the QB∞-rings. We investigate necessary and sufficient conditions under which an exchange ring is a QB∞-ring. The modules over an exchange QB∞-ring are studied. Also, we prove that every regular square matrix over an exchange QB∞-ring admits a diagonal reduction by pseudo-invertible matrices.

  17. Instrumentation for measurement of in-flight annihilations of 130 keV antiprotons on thin target foils

    Science.gov (United States)

    Todoroki, K.; Barna, D.; Hayano, R. S.; Aghai-Khozani, H.; Sótér, A.; Corradini, M.; Leali, M.; Lodi-Rizzini, E.; Mascagna, V.; Venturelli, L.; Prest, V.; Vallazza, L.; De Salvador, D.; Hori, M.

    2016-11-01

    We describe the instrumentation for an experiment to measure the cross sections of antiprotons with kinetic energies of 130±10 keV annihilating on carbon, palladium, and platinum target foils of sub-100 nm thicknesses. A 120 ns long pulsed beam containing 105 -106 antiprotons was allowed to traverse the foils, and the signal annihilations that resulted from this were isolated using a time-of-flight method. Backgrounds arose from Rutherford scattering of the antiprotons off the target foils, their annihilations in the target chamber walls, and π → μ → e decay of the charged pions that emerged from the annihilations. Some antiprotons slowed down and annihilated in the contamination on the target surfaces. This reduced the signal-to-background ratio of the measurement.

  18. Determination of the antiproton-to-electron mass ratio by precision laser spectroscopy of $\\overline{p}He^{+}$

    CERN Document Server

    Hori, M; Eades, John; Gomikawa, K; Hayano, R S; Ono, N; Pirkl, Werner; Widmann, E; Torii, H A; Juhász, B; Barna, D; Horváth, D

    2006-01-01

    A femtosecond optical frequency comb and continuous-wave pulse- amplified laser were used to measure 12 transition frequencies of antiprotonic helium to fractional precisions of (9-16) 10/sup -9lifetimes hitherto unaccessible to our precision laser spectroscopy method. Comparisons with three-body QED calculations yielded an antiproton-to-electron mass ratio of M/sub pmacron//m/sub e/=1836.152 674(5).

  19. Token Ring Project

    Directory of Open Access Journals (Sweden)

    Adela Ionescu

    2007-01-01

    Full Text Available Ring topology is a simple configuration used to connect processes that communicate among themselves. A number of network standards such as token ring, token bus, and FDDI are based on the ring connectivity. This article will develop an implementation of a ring of processes that communicate among themselves via pipe links. The processes are nodes in the ring. Each process reads from its standard input and writes in its standard output. N-1 process redirects the its standard output to a standard input of the process through a pipe. When the ring-structure is designed, the project can be extended to simulate networks or to implement algorithms for mutual exclusion

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

    CERN Document Server

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

    2000-01-01

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

  1. Token ring technology report

    CERN Document Server

    2013-01-01

    Please note this is a Short Discount publication. This report provides an overview of the IBM Token-Ring technology and products built by IBM and compatible vendors. It consists of two sections: 1. A summary of the design trade-offs for the IBM Token-Ring. 2. A summary of the products of the major token-ring compatible vendors broken down by adapters and components, wiring systems, testing, and new chip technology.

  2. On -Coherent Endomorphism Rings

    Indian Academy of Sciences (India)

    Li-Xin Mao

    2008-11-01

    A ring is called right -coherent if every principal right ideal is finitely presented. Let $M_R$ be a right -module. We study the -coherence of the endomorphism ring of $M_R$. It is shown that is a right -coherent ring if and only if every endomorphism of $M_R$ has a pseudokernel in add $M_R; S$ is a left -coherent ring if and only if every endomorphism of $M_R$ has a pseudocokernel in add $M_R$. Some applications are given.

  3. A Beautiful Ring

    Institute of Scientific and Technical Information of China (English)

    王对成

    2000-01-01

    Helen bought a very nice ring(戒指)and she wore it to the office the next day. Nobody saw her ring. She moved her hand this way and that, but still nobbdy in the offiee saw the ring on her finger. At tea time when they were sitting'round,she suddenly (突然地) stood up. “it is very hot here,”she said. “I think I'll take off my ring.”

  4. Homorooty in Rings

    Directory of Open Access Journals (Sweden)

    M. H. Hooshmand

    2010-03-01

    Full Text Available The topic of ”Homorooty” (for integer numbers has been introduced and studied in [2]. There are some applications of the homorooty in studying and solving some Diophantine equations and systems, as an interesting and useful elementary method. As a continuation of the Homorooty, we consider it for arbitrary rings and will study its properties in different rings, especially UFD and homorooty rings (which will be introduced. At last we shall state some applications of homorooty in studying some equations over homorooty rings

  5. Collisions of low-energy antiprotons and protons with atoms and molecules

    Energy Technology Data Exchange (ETDEWEB)

    Luehr, Armin

    2010-02-18

    Antiproton (anti p) collisions have evolved to a powerful tool for the testing of dynamic electron correlations in atoms and molecules. While advances in the understanding of anti p collisions with the simplest one- and two-electron atoms, H and He, have been achieved experiment and theory did not agree for low-energy anti p+He collisions (<40 keV), stimulating a vivid theoretical activity. On the other hand, only very few theoretical anti p studies can be found considering molecular as well as other atomic targets, in contrast to proton (p) collisions. This is in particular true for anti p impacts on H{sub 2} despite its fundamental role in representing the simplest two-electron molecule. The obtained results may be useful for the anti p experiments at CERN (e.g., antihydrogen production) and in particular for the facility design of low-energy anti p storage rings (e.g., at FLAIR) where a precise knowledge of the anti p interaction with the dominant residual-gas molecule H{sub 2} is needed. In this work a nonperturbative, time-dependent numerical approach is developed which describes ionization and excitation of atoms or molecules by either anti p or p impact based on the impact-parameter method. A spectral close-coupling method is employed for solving the time-dependent Schroedinger equation in which the scattering wave function is expanded in (effective) one- or two-electron eigenstates of the target. This includes for the first time a full two-electron, two-center description of the H{sub 2} molecule in anti p collisions. The radial part of the one-electron eigenstates is expanded in B splines while the two-electron basis is obtained with a configurationinteraction approach. Calculations are performed for anti p collisions with H, H{sub 2}{sup +}, and H{sub 2} as well as with He and alkali-metal atoms Li, Na, K, and Rb. Additionally, data are obtained for p collisions with H{sub 2}, Li, Na, and K. The developed method is tested and validated by detailed

  6. Collisions of low-energy antiprotons and protons with atoms and molecules

    International Nuclear Information System (INIS)

    Antiproton (anti p) collisions have evolved to a powerful tool for the testing of dynamic electron correlations in atoms and molecules. While advances in the understanding of anti p collisions with the simplest one- and two-electron atoms, H and He, have been achieved experiment and theory did not agree for low-energy anti p+He collisions (2 despite its fundamental role in representing the simplest two-electron molecule. The obtained results may be useful for the anti p experiments at CERN (e.g., antihydrogen production) and in particular for the facility design of low-energy anti p storage rings (e.g., at FLAIR) where a precise knowledge of the anti p interaction with the dominant residual-gas molecule H2 is needed. In this work a nonperturbative, time-dependent numerical approach is developed which describes ionization and excitation of atoms or molecules by either anti p or p impact based on the impact-parameter method. A spectral close-coupling method is employed for solving the time-dependent Schroedinger equation in which the scattering wave function is expanded in (effective) one- or two-electron eigenstates of the target. This includes for the first time a full two-electron, two-center description of the H2 molecule in anti p collisions. The radial part of the one-electron eigenstates is expanded in B splines while the two-electron basis is obtained with a configurationinteraction approach. Calculations are performed for anti p collisions with H, H2+, and H2 as well as with He and alkali-metal atoms Li, Na, K, and Rb. Additionally, data are obtained for p collisions with H2, Li, Na, and K. The developed method is tested and validated by detailed comparison of the present findings for p impacts and for anti p+He collisions with literature data. On the other hand, total and differential cross sections for ionization and excitation of the targets by anti p impact complement the sparse literature data of this kind. Results gained from different targets as well

  7. Further studies of double ionization of He, Ne, and Ar by fast and slow antiprotons

    Science.gov (United States)

    Andersen, L. H.; Hvelplund, P.; Knudsen, H.; Møller, S. P.; Pedersen, J. O. P.; Tang-Petersen, S.; Uggerhøj, E.; Elsener, K.; Morenzoni, E.

    1989-12-01

    Measurements of the ratio R between double- and single-ionization cross sections for antiproton impact on He, Ne, and Ar targets are reported for impact energies ranging from 65 keV to 20 MeV. At high energies the results are found to merge with proton results at around 20 MeV, and the high-energy limit of the common ratio is in good agreement with recent first-Born-calculation results for the helium target. The large difference previously observed in the ratio R for protons and antiprotons at energies between 0.5 and 5 MeV is found to persist down to the lowest energies investigated here.

  8. Further studies of double ionization of He, Ne, and Ar by fast and slow antiprotons

    Energy Technology Data Exchange (ETDEWEB)

    Andersen, L.H.; Hvelplund, P.; Knudsen, H.; Moller, S.P.; Pedersen, J.O.P.; Tang-Petersen, S.; Uggerhoj, E. (Institute of Physics, University of Aarhus, DK-8000 Aarhus C, Denmark (Denmark)); Elsener, K. (CERN, CH-1211 Geneva 23, (Switzerland)); Morenzoni, E. (PSI, CH-5234 Villigen, (Switzerland))

    1989-12-15

    Measurements of the ratio {ital R} between double- and single-ionization cross sections for antiproton impact on He, Ne, and Ar targets are reported for impact energies ranging from 65 keV to 20 MeV. At high energies the results are found to merge with proton results at around 20 MeV, and the high-energy limit of the common ratio is in good agreement with recent first-Born-calculation results for the helium target. The large difference previously observed in the ratio {ital R} for protons and antiprotons at energies between 0.5 and 5 MeV is found to persist down to the lowest energies investigated here.

  9. Spectral Intensities of Antiprotons and the lifetime of Cosmic Rays in the Galaxy

    CERN Document Server

    Cowsik, Ramanath

    2015-01-01

    In this paper we note that the spectral intensities of antiprotons observed in Galactic cosmic rays in the energy range ~ 1-100 GeV by BESS, PAMELA and AMS instruments display nearly the same spectral shape as that generated by primary cosmic rays through their interaction with matter in the interstellar medium, without any significant modifications. More importantly, a constant residence time of ~ 2.5 +/-0.7 million years in the Galactic volume, independent of the energy of cosmic rays, matches the observed intensities. A small additional component of secondary antiprotons in the energy below 10 GeV, generated in cocoon-like regions surrounding the cosmic-ray sources, seems to be present. We discuss this result in the context of observations of other secondary components like positrons and Boron, and conclude with general remarks about the origins and propagation of cosmic rays.

  10. Secondary emission monitor for keV ion and antiproton beams

    CERN Document Server

    Sosa, Alejandro; Bravin, Enrico; Harasimowciz, Janusz; Welsch, C P

    2013-01-01

    Beam profile monitoring of low intensity keV ion and antiproton beams remains a challenging task. A Sec- ondary electron Emission Monitor (SEM) has been de- signed to measure profiles of beams with intensities below 107 and energies as low as 20 keV. The monitor is based on a two stage microchannel plate (MCP) and a phosphor screen facing a CCD camera. Its modular design allows two different operational setups. In this contribution we present the design of a prototype and discuss results from measurements with antiprotons at the AEgIS experiment at CERN. This is then used for a characterization of the monitor with regard to its possible future use at different facilities.

  11. Investigation of silicon sensors for their use as antiproton annihilation detectors

    Energy Technology Data Exchange (ETDEWEB)

    Pacifico, N., E-mail: nicola.pacifico@cern.ch [University of Bergen, Institute of Physics and Technology, Allégaten 55, 5007 Bergen (Norway); Aghion, S. [Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano (Italy); Istituto Nazionale di Fisica Nucleare, Sez. di Milano, Via Celoria 16, 20133 Milano (Italy); Ahlén, O. [European Organisation for Nuclear Research, Physics Department, 1211 Geneva 23 (Switzerland); Belov, A.S. [Institute for Nuclear Research of the Russian Academy of Sciences, Moscow 117312 (Russian Federation); Bonomi, G. [University of Brescia, Department of Mechanical and Industrial Engineering, Via Branze 38, 25133 Brescia (Italy); Istituto Nazionale di Fisica Nucleare, Sez. di Pavia, Via Agostino Bassi 6, 27100 Pavia (Italy); Bräunig, P. [Kirchhoff Institute for Physics, Im Neuenheimer Feld 227, 69120 Heidelberg (Germany); Bremer, J. [European Organisation for Nuclear Research, Physics Department, 1211 Geneva 23 (Switzerland); Brusa, R.S. [Department of Physics, University of Trento, via Sommarive 14, 38123 Povo, Trento (Italy); INFN-TIFPA, via Sommarive 14, 38123 Povo, Trento (Italy); Burghart, G. [European Organisation for Nuclear Research, Physics Department, 1211 Geneva 23 (Switzerland); Cabaret, L. [Laboratoire Aimé Cotton, CNRS, Université Paris Sud, ENS Cachan, Bâtiment 505, Campus d' Orsay, 91405 Orsay Cedex (France); Caccia, M. [University of Insubria, Dipartimento di Scienza ed Alta Tecnologia, via Valleggio 11, Como (Italy); Canali, C. [University of Zurich, Physics Institute, Winterthurerstrasse 190, 8057 Zurich (Switzerland); Caravita, R. [Istituto Nazionale di Fisica Nucleare, Sez. di Genova, Via Dodecaneso 33, 16146 Genova (Italy); University of Genoa, Department of Physics, Via Dodecaneso 33, 16146 Genova (Italy); Castelli, F. [University of Milano, Department of Physics, Via Celoria 16, 20133 Milano (Italy); and others

    2014-11-21

    We present here a new application of silicon sensors aimed at the direct detection of antinucleons annihilations taking place inside the sensor's volume. Such detectors are interesting particularly for the measurement of antimatter properties and will be used as part of the gravity measurement module in the AEg{sup ¯}IS experiment at the CERN Antiproton Decelerator. One of the goals of the AEg{sup ¯}IS experiment is to measure the gravitational acceleration of antihydrogen with 1% precision. Three different silicon sensor geometries have been tested with an antiproton beam to investigate their properties as annihilation detection devices: strip planar, 3D pixels and monolithic pixel planar. In all cases we were successfully detecting annihilations taking place in the sensor and we were able to make a first characterization of the clusters and tracks.

  12. Anti- and Hypermatter Research at the Facility for Antiproton and Ion Research FAIR

    Science.gov (United States)

    Steinheimer, J.; Xu, Z.; Rau, P.; Sturm, C.; Stöcker, H.

    2013-07-01

    Within the next six years, the Facility for Antiproton and Ion Research (FAIR) is built adjacent to the existing accelerator complex of the GSI Helmholtz Center for Heavy Ion Research at Darmstadt, Germany. Thus, the current research goals and the technical possibilities are substantially expanded. With its worldwide unique accelerator and experimental facilities, FAIR will provide a wide range of unprecedented fore-front research in the fields of hadron, nuclear, atomic, plasma physics and applied sciences which are summarized in this article. As an example this article presents research efforts on strangeness at FAIR using heavy ion collisions, exotic nuclei from fragmentation and antiprotons to tackle various topics in this area. In particular, the creation of hypernuclei, metastable exotic multi-hypernuclear objects (MEMOs) and antimatter is investigated.

  13. Ionization of helium by slow antiproton impact: total and differential cross sections

    CERN Document Server

    Borbély, S; Nagele, S; Tőkési, K; Nagy, L; Burgdörfer, J

    2014-01-01

    We theoretically investigate the single and double ionization of the He atom by antiproton impact for projectile energies ranging from $3$~keV up to $1000$~keV. We obtain accurate total cross sections by directly solving the fully correlated two-electron time-dependent Schr\\"odinger equation and by performing classical trajectory Monte-Carlo calculations. The obtained quantum-mechanical results are in excellent agreement with the available experimental data. Along with the total cross sections, we also present the first fully \\textit{ab initio} doubly differential data for single ionization at 10 and 100~keV impact energies. In these differential cross sections we identify the binary-encounter peak along with the anticusp minimum. Furthermore, we also point out the importance of the post-collisional electron-projectile interaction at low antiproton energies which significantly suppresses electron emission in the forward direction.

  14. Scattered antiproton polarization in pp elastic scattering at 220 MeV in bubble chamber

    CERN Document Server

    Ohsugi, T

    1973-01-01

    The polarization of antiproton scattering in pp elastic collision has been measured in the four intervals of the CM scattering angle theta /sup */ less than 90 degrees by means of double scattering in a bubble chamber. The analysis has been performed on the basis of 999 double elastic events which have been found in about 100K pictures of the 81- cm Saclay hydrogen bubble chamber exposed to a 0.7 GeV/c antiproton beam from the CERN PS. The obtained values of polarization show the maximum value 0.52+or-0.19 at theta /sup */=56 degrees . The polarization for pp scattering seems to be larger than that for pp scattering. The results are also compared with the potential model by Bryan and Phillips (1968) and with the modified diffraction model by Frahn and Venter (1964). Possible systematic errors in the present experiment are discussed in detail. (17 refs).

  15. MOBILE LEARING - possibilities and perspectives

    DEFF Research Database (Denmark)

    Larsen, Lasse Juel

    2009-01-01

    content in school. Explicitly this paper will use the SMS-based locative art “Surrender Control” (2001) and Knifeandforks “The Wrench” (2008) as cases for discussing possibilities and perspectives in learning with text-messaging. It will draw upon knowledge systemization as a tool to understand delivered......This paper proposes that SMS (Short Message Service) or text-messaging on mobile devices can serve as an extension or possible create another way of learning traditional scholastic content normally associated with the school system. The potential of the SMS is still very much untapped and largely...

  16. Slope analysis for elastic proton-proton and proton-antiproton scattering

    OpenAIRE

    Okorokov, V. A.

    2008-01-01

    The diffraction slope parameter is investigated for elastic proton-proton and proton-antiproton scattering based on the all available experimental data at intermediate square of momentum transfer in the main. Energy dependence of the elastic diffraction slope is approximated by various analytic functions in a model-independent fashion. The expanded standard logarithmic approximations allow to describe experimental slopes in all available energy range at qualitative level reasonably. Various f...

  17. Diffraction slopes for elastic proton-proton and proton-antiproton scattering

    OpenAIRE

    Okorokov, V. A.

    2008-01-01

    The diffraction slope parameter is investigated for elastic proton-proton and proton-antiproton scattering based on the all available experimental data at low momentum transfer values. Energy dependence of the elastic diffraction slopes is approximated by various analytic functions. The expanded "standard" logarithmic approximations allow to describe experimental slopes in all available energy range reasonably. Various approximations differ from each other both in the low energy and very high...

  18. 8 GeV beam line optics optimization for the rapid antiproton transfers at Fermilab

    Energy Technology Data Exchange (ETDEWEB)

    Nagaslaev, V.; Lebedev, V.; Morgan, J.; Vander Meulen, D.; /Fermilab

    2007-02-01

    Tevatron Run-II upgrade requires a significant increase of the efficiency and speed of the antiproton transfers from the Accumulator to the Recycler. The goal for the total transfer time is challenging a reduction from 1 hour down to a few minutes. Here we discuss the beam line optics aspects of this project. Results of lattice measurements and optimization are analyzed in terms of transport efficiency and stability.

  19. Neutral strange particle production in antiproton-nucleus annihilation at low energies

    International Nuclear Information System (INIS)

    The cross sections of the Λ- and KS0-meson production in antiproton annihilation on nuclei at low energies (Epbar- and K-meson rescattering, Λ production in reactions with π- and ω-mesons is also considered. It is shown that these processes ensure a significant Λ-production even in the low energy region well below the ΛΛ-bar-threshold. 18 refs.; 1 tab

  20. Ring Around a Galaxy

    Science.gov (United States)

    1999-01-01

    Space Telescope Science Institute astronomers are giving the public chances to decide where to aim NASA's Hubble Space Telescope. Guided by 8,000 Internet voters, Hubble has already been used to take a close-up, multi-color picture of the most popular object from a list of candidates, the extraordinary 'polar-ring' galaxy NGC 4650A. Located about 130 million light-years away, NGC 4650A is one of only 100 known polar-ring galaxies. Their unusual disk-ring structure is not yet understood fully. One possibility is that polar rings are the remnants of colossal collisions between two galaxies sometime in the distant past, probably at least 1 billion years ago. What is left of one galaxy has become the rotating inner disk of old red stars in the center. Meanwhile, another smaller galaxy which ventured too close was probably severely damaged or destroyed. The bright bluish clumps, which are especially prominent in the outer parts of the ring, are regions containing luminous young stars, examples of stellar rebirth from the remnants of an ancient galactic disaster. The polar ring appears to be highly distorted. No regular spiral pattern stands out in the main part of the ring, and the presence of young stars below the main ring on one side and above on the other shows that the ring is warped and does not lie in one plane. Determining the typical ages of the stars in the polar ring is an initial goal of our Polar Ring Science Team that can provide a clue to the evolution of this unusual galaxy. The HST exposures were acquired by the Hubble Heritage Team, consisting of Keith Noll, Howard Bond, Carol Christian, Jayanne English, Lisa Frattare, Forrest Hamilton, Anne Kinney and Zolt Levay, and guest collaborators Jay Gallagher (University of Wisconsin-Madison), Lynn Matthews (National Radio Astronomy Observatory-Charlottesville), and Linda Sparke (University of Wisconsin-Madison).

  1. Unified interpretation of cosmic-ray nuclei and antiproton recent measurements

    International Nuclear Information System (INIS)

    We use our numerical code, DRAGON, to study the implications and the impact of recent CREAM and PAMELA data on our knowledge of the propagation properties of cosmic ray nuclei with energy >or similar 1 GeV/n in the Galaxy. We will show that B/C (as well as N/O and C/O) and anti p/p data (especially including recent PAMELA results) can consistently be matched within a unique diffusion-reacceleration model. The requirement that light nuclei and anti p data are both reproduced within experimental uncertainties places stringent limits on suitable propagation parameters. In particular, we find the allowed range of the diffusion coefficient spectral index to be 0.38A ≅15 kms-1) is allowed. Furthermore, we do not need to introduce any ad hoc break in the injection spectrum of primary cosmic rays. If antiproton data are not used to constrain the propagation parameters, a larger set of models is allowed. In this case, we determine which combinations of the relevant parameters maximize and minimize the antiproton flux under the condition of still fitting light nuclei data at 95% C.L. These models may then be used to constrain a possible extra antiproton component arising from astrophysical or exotic sources (e.g. dark matter annihilation or decay). (orig.)

  2. Heavy flavour production and heavy flavour mixing at the CERN proton-antiproton collider

    International Nuclear Information System (INIS)

    In this thesis some results of the proton-antiproton-collision experiment UA1 with the CERN Super Proton-Antiproton Synchrotron are presented and interpreted. Ch. 1 contians a general introduction to the physics motivations behind the proton-antiproton-collider project, a brief description of the CERN facilities and a summary of collider and UA1 physics achievements. Furthermore the concept of studying heavy flavours via their weak decays into muons is introduced. Ch. 2 gives a brief overview of the UA1 experimental set-up, while those parts of the detector that are relevant for the analysis, presented in this thesis, is discussed in some more detail. Ch. 3 contains a short introduction to, and motivation for the use of Monte Carlo techniques in event simulations, while Ch. 4 describes the framework of the recently developed 'EUROJET' event generator. In Ch. 5 a treatment is given of the theoretical background and concepts like 'quark-mixing' and 'CP-violation' are explained, also other useful definitions and formulae are introduced on which the later analysis of the same-sign to opposite-sign dimuon ratio is built. Data collection and event reconstruction is the subject of Ch. 6, while a detailed comparison between the theoretical models and experimentally obtained distributions is given in Ch. 7. Finally, in Ch. 8 some concluding remarks are made. 182 refs.; 81 figs.; 9 tabs

  3. Measurements of Wake-Riding Electrons in Antiproton-Carbon-Foil Collisions

    CERN Multimedia

    2002-01-01

    When a charged particle passes through dielectric media, e.g. a thin carbon foil, a ``wake'' is induced. The characteristic wake-potential shows an oscillatory behaviour, with a wavelength of about $ 2 \\pi v _{p} / \\omega _{p} _{l} $ where $ v _{p} $ is the projectile velocity and $ \\omega _{p} _{l} $ the plasmon energy of the target. This induced wake potential is superimposed on the Coulomb potential of the projectile, the latter leading to a pronounced ``cusp'' of electrons leaving the solid at $ v _{e} app v _{p} $ for positively charged projectiles in the MeV region. Correspondingly, an ``anti-cusp'' is expected for antiprotons. \\\\ \\\\ In the solid, the wake-potential leads to an attractive force on electrons, and a dynamic electronic state is predicted both for proton and antiproton projectiles. In the solid, the wake-riding electrons are travelling with the projectile speed $ v _{p} $ Upon exit of the foil, the electron released from the wake-riding state of an antiproton will suddenly find itself in th...

  4. Antiproton-to-Proton Ratios for ALICE Heavy-Ion Collisions

    CERN Document Server

    Tawfik, A

    2010-01-01

    Assuming that the final state of hadronization takes place along the freezeout line, which is defined by a constant entropy density, the antiproton-to-proton ratios produced in heavy-ion collisions are studied in framework of the hadron resonance gas (HRG) model. A phase transition from quark--gluon plasma to hadrons, a hadronization, has been conjectured in order to allow modifications in the phase space volume and thus in single--particle distribution function. Implementing both modifications in the grand--canonical partition function and taking into account the experimental acceptance in heavy-ion collisions, the antiproton-to-proton ratios over center-of-mass energies $\\sqrt{s}$ ranging from AGS to RHIC are very well reproduced by the HRG model. Comparing with the same particle ratios in $pp$ collisions results in a gradually narrowing discrepancy with increasing $\\sqrt{s}$. At LHC energy, the ALICE antiproton-to-proton ratios in $pp$ collisions turn to be very well described by HRG model as well. It is l...

  5. Cosmic positron and antiproton constraints on the gauge-Higgs Dark Matter

    CERN Document Server

    Cheung, Kingman; Tseng, Po-Yan

    2010-01-01

    We calculate the cosmic ray positron and antiproton spectra of a gauge-Higgs dark matter candidate in a warped five-dimensional $SO(5) \\times U(1)$ gauge-Higgs unification model. The stability of the gauge-Higgs boson is guaranteed by the H parity under which only the Higgs boson is odd at low energy. The 4-point vertices of HHW^+W^- and HHZZ, allowed by H parity conservation, have the same magnitude as in the standard model, which yields efficient annihilation rate for $m_H > m_W$. The most dominant annihilation channel is $H H \\to W^+ W^-$ followed by the subsequent decays of the $W$ bosons into positrons or quarks, which undergo fragmentation into antiproton. Comparing with the observed positron and antiproton spectra with the PAMALA and Fermi/LAT, we found that the Higgs boson mass cannot be larger than 90 GeV, in order not to overrun the observations. Together with the constraint on not overclosing the Universe, the valid range of the dark matter mass is restricted to 70-90 GeV.

  6. Cosmic positron and antiproton constraints on the gauge-Higgs dark matter

    Energy Technology Data Exchange (ETDEWEB)

    Cheung, Kingman; Song, Jeonghyeon [Division of Quantum Phases and Devices, School of Physics, Konkuk university, Seoul 143-701 (Korea, Republic of); Tseng, Po-Yan, E-mail: cheung@phys.nthu.edu.tw, E-mail: jeonghyeon.song@gmail.com, E-mail: d9722809@oz.nthu.edu.tw [Department of Physics, National Tsing Hua University, Hsinchu 300, Taiwan (China)

    2010-09-01

    We calculate the cosmic ray positron and antiproton spectra of a gauge-Higgs dark matter candidate in a warped five-dimensional SO(5) × U(1) gauge-Higgs unification model. The stability of the gauge-Higgs boson is guaranteed by the H parity under which only the Higgs boson is odd at low energy. The 4-point vertices of HHW{sup +}W{sup −} and HHZZ, allowed by H parity conservation, have the same magnitude as in the standard model, which yields efficient annihilation rate for m{sub H} > m{sub W}. The most dominant annihilation channel is HH → W{sup +}W{sup −} followed by the subsequent decays of the W bosons into positrons or quarks, which undergo fragmentation into antiproton. Comparing with the observed positron and antiproton spectra with the PAMALA and Fermi/LAT, we found that the Higgs boson mass cannot be larger than 90 GeV, in order not to overrun the observations. Together with the constraint on not overclosing the Universe, the valid range of the dark matter mass is restricted to 70–90 GeV.

  7. Cosmic positron and antiproton constraints on the gauge-Higgs dark matter

    International Nuclear Information System (INIS)

    We calculate the cosmic ray positron and antiproton spectra of a gauge-Higgs dark matter candidate in a warped five-dimensional SO(5) × U(1) gauge-Higgs unification model. The stability of the gauge-Higgs boson is guaranteed by the H parity under which only the Higgs boson is odd at low energy. The 4-point vertices of HHW+W− and HHZZ, allowed by H parity conservation, have the same magnitude as in the standard model, which yields efficient annihilation rate for mH > mW. The most dominant annihilation channel is HH → W+W− followed by the subsequent decays of the W bosons into positrons or quarks, which undergo fragmentation into antiproton. Comparing with the observed positron and antiproton spectra with the PAMALA and Fermi/LAT, we found that the Higgs boson mass cannot be larger than 90 GeV, in order not to overrun the observations. Together with the constraint on not overclosing the Universe, the valid range of the dark matter mass is restricted to 70–90 GeV

  8. Application of high quality antiproton beam to study charmonium and exotics above DD-bar threshold

    International Nuclear Information System (INIS)

    The spectroscopy of charmonium and exotic states with hidden charm is discussed. It is a good testing tool for theories of strong interactions including QCD in both perturbative and non-perturbative regime, lattice QCD, potential models and phenomenological models. An elaborated analysis of charmonium and charmed hybrid spectrum is given, and attempts to interpret recent experimental data in the above DD-bar threshold region are considered. Experiments using antiproton beam take advantage of the intensive production of particle-antiparticle pairs in antiproton-proton annihilations. Experimental data from different collaboration are analyzed with special attention given to new states with hidden charm that were discovered recently. Some of these states can be interpreted as higher-laying S, P and D wave charmonium states. But much more data on different decay modes are needed before firmer conclusions can be made. These data can be derived directly from the experiments using high quality antiproton beam with momentum up to 15 GeV/c. (authors)

  9. Limits on dark matter from AMS-02 antiproton and positron fraction data

    Science.gov (United States)

    Lu, Bo-Qiang; Zong, Hong-Shi

    2016-05-01

    Herein we derive limits on dark matter annihilation cross section and lifetime using measurements of the AMS-02 antiproton ratio and positron fraction data. In deriving the limits, we consider the scenario of secondary particles accelerated in supernova remnants (SNRs), which has been argued to be able to reasonably account for the AMS-02 high-energy positron/antiproton fraction/ratio data. We parametrize the contribution of secondary particles accelerated in SNRs and then fit the observational data within the conventional cosmic ray propagation model by adopting the galprop code. We use the likelihood ratio test to determine the 95% confidence level upper limits of possible dark matter (DM) contribution to the antiproton/positron fractions measured by AMS-02. Under the assumption taken in this work, we find that our limits are stronger than that set by the Fermi-LAT gamma ray Pass 8 data observation on the dwarf spheroidal satellite galaxies. We show that the solar modulation (cosmic ray propagation) parameters can play a non-negligible role in modifying the constraints on dark matter annihilation cross section and lifetime for mχ100 GeV ), where mχ is the rest mass of dark matter particles. We also find that constrains on DM parameters from AMS-02 data would become more stringent when the solar modulation is weak. Using these results, we also put limits on the effective field theory of dark matter.

  10. A new calculation of the cosmic-ray antiproton spectrum in the Galaxy and heliospheric modulation effects on this spectrum using a drift plus wavy current sheet model

    International Nuclear Information System (INIS)

    The expected interstellar antiproton spectrum arising from cosmic-ray interactions in the Galaxy is recalculated, and the modulation of both antiprotons and protons is calculated using a two-dimensional modulation model incorporating gradient and curvature drifts and a wavy current sheet as well as the usual diffusion, convection, and energy-loss effects. Significant differences in the antiproton/proton ratio for different solar magnetic field polarities are predicted as well as a 'low-energy' component for antiprotons below about 1 GeV. 28 refs

  11. PAMELA results on the cosmic-ray antiproton flux from 60 MeV to 180 GeV in kinetic energy

    CERN Document Server

    Adriani, O; Bazilevskaya, G A; Bellotti, R; Boezio, M; Bogomolov, E A; Bonechi, L; Bongi, M; Bonvicini, V; Borisov, S; Bottai, S; Bruno, A; Cafagna, F; Campana, D; Carbone, R; Carlson, P; Casolino, M; Castellini, G; Consiglio, L; De Pascale, M P; De Santis, C; De Simone, N; Di Felice, V; Galper, A M; Gillard, W; Grishantseva, L; Hofverberg, P; Jerse, G; Karelin, A V; Koldashov, S V; Krutkov, S Y; Kvashnin, A N; Leonov, A; Malvezzi, V; Marcelli, L; Mayorov, A G; Menn, W; Mikhailov, V V; Mocchiutti, E; Monaco, A; Mori, N; Nikonov, N; Osteria, G; Papini, P; Pearce, M; Picozza, P; Pizzolotto, C; Ricci, M; Ricciarini, S B; Rossetto, L; Simon, M; Sparvoli, R; Spillantini, P; Stozhkov, Y I; Vacchi, A; Vannuccini, E; Vasilyev, G; Voronov, S A; Wu, J; Yurkin, Y T; Zampa, G; Zampa, N; Zverev, V G

    2010-01-01

    The satellite-borne experiment PAMELA has been used to make a new measurement of the cosmic-ray antiproton flux and the antiproton-to-proton flux ratio which extends previously published measurements down to 60 MeV and up to 180 GeV in kinetic energy. During 850 days of data acquisition approximately 1500 antiprotons were observed. The measurements are consistent with purely secondary production of antiprotons in the galaxy. More precise secondary production models are required for a complete interpretation of the results.

  12. Revocable Ring Signature

    Institute of Scientific and Technical Information of China (English)

    Dennis Y. W. Liu; Joseph K. Liu; Yi Mu; Willy Susilo; Duncan S. Wong

    2007-01-01

    Group signature allows the anonymity of a real signer in a group to be revoked by a trusted party called group manager. It also gives the group manager the absolute power of controlling the formation of the group. Ring signature, on the other hand, does not allow anyone to revoke the signer anonymity, while allowing the real signer to forma group (also known as a ring) arbitrarily without being controlled by any other party. In this paper, we propose a new variant for ring signature, called Revocable Ring Signature. The signature allows a real signer to form a ring arbitrarily while allowing a set of authorities to revoke the anonymity of the real signer. This new variant inherits the desirable properties from both group signature and ring signature in such a way that the real signer will be responsible for what it has signed as the anonymity is revocable by authorities while the real signer still has the freedom on ring formation. We provide a formal security model for revocable ring signature and propose an efficient construction which is proven secure under our security model.

  13. EBT ring physics

    International Nuclear Information System (INIS)

    This workshop attempted to evaluate the status of the current experimental and theoretical understanding of hot electron ring properties. The dominant physical processes that influence ring formation, scaling, and their optimal behavior are also studied. Separate abstracts were prepared for each of the 27 included papers

  14. Jupiter's Rings: Sharpest View

    Science.gov (United States)

    2007-01-01

    The New Horizons spacecraft took the best images of Jupiter's charcoal-black rings as it approached and then looked back at Jupiter. The top image was taken on approach, showing three well-defined lanes of gravel- to boulder-sized material composing the bulk of the rings, as well as lesser amounts of material between the rings. New Horizons snapped the lower image after it had passed Jupiter on February 28, 2007, and looked back in a direction toward the sun. The image is sharply focused, though it appears fuzzy due to the cloud of dust-sized particles enveloping the rings. The dust is brightly illuminated in the same way the dust on a dirty windshield lights up when you drive toward a 'low' sun. The narrow rings are confined in their orbits by small 'shepherding' moons.

  15. The Enceladus Ring

    Science.gov (United States)

    2006-01-01

    [figure removed for brevity, see original site] The Enceladus Ring (labeled) This excellent view of the faint E ring -- a ring feature now known to be created by Enceladus -- also shows two of Saturn's small moons that orbit within the ring, among a field of stars in the background. The E ring extends from three to eight Saturn radii -- about 180,000 kilometers (118,000 miles) to 482,000 kilometers (300,000 miles). Its full extent is not visible in this view. Calypso (22 kilometers, or 14 miles across) and Helene (32 kilometers, or 20 miles across) orbit within the E ring's expanse. Helene skirts the outer parts of the E ring, but here it is projected in front of a region deeper within the ring. Calypso and Helene are trojan satellites, or moons that orbit 60 degrees in front or behind a larger moon. Calypso is a Tethys trojan and Helene is a trojan of Dione. An interesting feature of note in this image is the double-banded appearance of the E-ring, which is created because the ring is somewhat fainter in the ringplane than it is 500-1,000 kilometers (300-600 miles) above and below the ringplane. This appearance implies that the particles in this part of the ring have nonzero inclinations (a similar affect is seen in Jupiter's gossamer ring). An object with a nonzero inclination does not orbit exactly at Saturn's ringplane. Instead, its orbit takes it above and below the ringplane. Scientists are not entirely sure why the particles should have such inclinations, but they are fairly certain that the reason involves Enceladus. One possible explanation is that all the E ring particles come from the plume of icy material that is shooting due south out of the moon's pole. This means all of the particles are created with a certain velocity out of the ringplane, and then they orbit above and below that plane. Another possible explanation is that Enceladus produces particles with a range of speeds, but the moon gravitationally scatters any particles that lie very close to

  16. Dynamics of the Uranian Rings

    Science.gov (United States)

    Dermott, S. F.

    1984-01-01

    Some of the problems of the shepherding satellite model of Goldreich ant tremaine are discussed. The following topics are studied: (1) optical depths of the all the observed narrow rings; (2) satellite and ring separation timescales; (3) ring edge sharpness; (4) shock formation in narrow rings; (5) the existence of small satellites near the Uranian rings; and (6) the apse and node alignments of the eccentric and inclined rings.

  17. Ring chromosome 13

    DEFF Research Database (Denmark)

    Brandt, C A; Hertz, Jens Michael; Petersen, M B;

    1992-01-01

    A stillborn male child with anencephaly and multiple malformations was found to have the karyotype 46,XY,r(13) (p11q21.1). The breakpoint at 13q21.1, determined by high resolution banding, is the most proximal breakpoint ever reported in patients with ring chromosome 13. In situ hybridisation...... with the probe L1.26 confirmed the derivation from chromosome 13 and DNA polymorphism analysis showed maternal origin of the ring chromosome. Our results, together with a review of previous reports of cases with ring chromosome 13 with identified breakpoints, could neither support the theory of distinct clinical...

  18. Group ring cryptography

    CERN Document Server

    Hurley, Barry

    2011-01-01

    Cryptographic systems are derived using units in group rings. Combinations of types of units in group rings give units not of any particular type. This includes cases of taking powers of units and products of such powers and adds the complexity of the {\\em discrete logarithm} problem to the system. The method enables encryption and (error-correcting) coding to be combined within one system. These group ring cryptographic systems may be combined in a neat way with existing cryptographic systems, such as RSA, and a combination has the combined strength of both systems. Examples are given.

  19. Saturn's Rings are Fractal

    OpenAIRE

    Li, Jun; Ostoja-Starzewski, Martin

    2012-01-01

    Over the past few decades, various conjectures were advanced that Saturn's rings are Cantor-like sets, although no convincing fractal analysis of actual images has ever appeared. We focus on the images sent by the Cassini spacecraft mission: slide #42 "Mapping Clumps in Saturn's Rings" and slide #54 "Scattered Sunshine". Using the box-counting method, we determine the fractal dimension of rings seen here (and in several other images from the same source) to be consistently about 1.6~1.7. This...

  20. Ringed Seal Distribution Map

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains GIS layers that depict the known spatial distributions (i.e., ranges) of the five subspecies of ringed seals (Phoca hispida). It was produced...

  1. Remotely operated locking ring

    International Nuclear Information System (INIS)

    A ring for fastening tubes with conical ends with only one manipulator is described. It is opened by compression of a spring with the manipulator grip, placed on the tubes to fasten, closed by releasing the pressure and locked

  2. The g-2 ring

    CERN Multimedia

    1974-01-01

    The precise measurement of "g-2", the anomalous magnetic moment of the muon, required a special muon storage ring with electrostatic focussing and very accurate knowledge of the magnetic bending field. For more details see under photo 7405430.

  3. Storage Ring EDM Experiments

    Science.gov (United States)

    Semertzidis, Yannis K.

    2016-04-01

    Dedicated storage ring electric dipole moment (EDM) methods show great promise advancing the sensitivity level by a couple orders of magnitude over currently planned hadronic EDM experiments. We describe the present status and recent updates of the field.

  4. Child sex rings.

    OpenAIRE

    Wild, N J; Wynne, J M

    1986-01-01

    Details of 11 child sex rings identified in one working class community were obtained by interviewing investigating police officers and examining health and social services records. The rings contained 14 adult male perpetrators and 175 children aged 6-15 years. Most perpetrators used child ringleaders to recruit victims; others became a "family friend" or obtained a position of authority over children. Secrecy was encouraged and bribery, threats, and peer pressure used to induce participatio...

  5. Can we explain AMS-02 antiproton and positron excesses simultaneously by nearby supernovae without pulsars or dark matter?

    Science.gov (United States)

    Kohri, Kazunori; Ioka, Kunihito; Fujita, Yutaka; Yamazaki, Ryo

    2016-02-01

    We explain the excess of the antiproton fraction recently reported by the AMS-02 experiment by considering collisions between cosmic-ray protons accelerated by a local supernova remnant and the surrounding dense cloud. The same "pp collisions" provide the right ratio of daughter particles to fit the observed positron excess simultaneously in the natural model parameters. The supernova happened in relatively lower metallicity than the major cosmic-ray sources. The cutoff energy of electrons marks the supernova age of {˜ }105 years, while the antiproton excess may extend to higher energy. Both antiproton and positron fluxes are completely consistent with our predictions in an earlier paper [Y. Fujita et al., Phys. Rev. D 80, 063003 (2009) [arXiv:0903.5298 [astro-ph.HE

  6. The Angular Distribution Of Electron-positron Pairs From Exclusive Charmonium Decays In Antiproton-proton Annihilations

    CERN Document Server

    McTaggart, R J

    1998-01-01

    The angular distributions of the charmonium resonances J/ Y (3097) and Y (3686) in their exclusive decay to an electron-positron pair are studied. Experiment 835 at the Fermi National Accelerator Laboratory produced charmonium resonances by annihilating protons with antiprotons in the Fixed Target Mode of the Antiproton Accumulator: A stochastically cooled antiproton beam collides with a hydrogen gas jet, which forms clusters under the right pressure and low temperature. The charmonium decay products are detected out of a large hadronic background with the help of a segmented lead glass sampling calorimeter, which is sensitive to the high mass electron-positron charmonium decay, and a set of Cerenkov threshold detectors that provide good electron/pion separation. Several factors influence the angular distribution parameter l taken from the angular distribution, including the energy scale of the resonance, the coupling strength of the charmonium atom, and how quarks and gluons interact in the dissolution...

  7. Highlights on gamma rays, neutrinos and antiprotons from TeV Dark Matter

    Directory of Open Access Journals (Sweden)

    Gammaldi Viviana

    2016-01-01

    Full Text Available It has been shown that the gamma-ray flux observed by HESS from the J1745-290 Galactic Center source is well fitted as the secondary gamma-rays photons generated from Dark Matter annihilating into Standard Model particles in combination with a simple power law background. The neutrino flux expected from such Dark Matter source has been also analyzed. The main results of such analyses for 50 TeV Dark Matter annihilating into W+W− gauge boson and preliminary results for antiprotons are presented.

  8. Measurement of (anti)deuteron and (anti)proton production in DIS at HERA

    CERN Document Server

    Chekanov, S; Magill, S; Musgrave, B; Nicholass, D; Repond, J; Yoshida, R; Mattingly, M C K; Jechow, M; Pavel, N; Yagues-Molina, A G; Antonelli, S; Antonioli, P; Bari, G; Basile, M; Bellagamba, L; Bindi, M; Boscherini, D; Bruni, A; Bruni, G; Cifarelli, L; Cindolo, F; Contin, A; Corradi, M; De Pasquale, S; Iacobucci, G; Margotti, A; Nania, R; Polini, A; Sartorelli, G; Zichichi, A; Bartsch, D; Brock, I; Goers, S; Hartmann, H; Hilger, E; Jakob, H P; Jüngst, M; Kind, O M; Nuncio-Quiroz, A E; Paul, E; Renner, R; Samson, U; Schonberg, V; Shehzadi, R; Wlasenko, M; Brook, N H; Heath, G P; Morris, J D; Namsoo, T; Capua, M; Fazio, S; Mastroberardino, A; Schioppa, M; Susinno, G; Tassi, E; Kim, J Y; Ma, K J; Ibrahim, Z A; Kamaluddin, B; Wan-Abdullah, W A T; Ning, Y; Ren, Z; Sciulli, F; Chwastowski, J; Eskreys, A; Figiel, J; Galas, A; Gil, M; Olkiewicz, K; Stopa, P; Zawiejski, L; Adamczyk, L; Bold, T; Grabowska-Bold, I; Kisielewska, D; Lukasik, J; Przybycien, M; Suszycki, L; Kotanski, A; Slominski, W; Adler, V; Behrens, U; Bloch, I; Blohm, C; Bonato, A; Borras, K; Ciesielski, R; Coppola, N; Dossanov, A; Drugakov, V; Fourletova, J; Geiser, A; Gladkov, D; Göttlicher, P; Grebenyuk, J; Gregor, I; Haas, T; Hain, W; Horn, C; Huttmann, A; Kahle, B; Katkov, I I; Klein, U; Kötz, U; Kowalski, H; Lobodzinska, E; Löhr, B; Mankel, R; Melzer-Pellmann, I A; Miglioranzi, S; Montanari, A; Notz, D; Rinaldi, L; Roloff, P; Rubinsky, I; Santamarta, R; Schneekloth, U; Spiridonov, A; Stadie, H; Szuba, D; Szuba, J; Theedt, T; Wolf, G; Wrona, K; Youngman, C; Zeuner, W; Lohmann, W; Schlenstedt, S; Barbagli, G; Gallo, E; Pelfer, P G; Bamberger, A; Dobur, D; Karstens, F; Vlasov, N N; Bussey, P J; Doyle, A T; Dunne, W; Ferrando, J; Forrest, M; Saxon, D H; Skillicorn, I O; Gialas, I; Papageorgiu, K; Gosau, T; Holm, U; Klanner, R; Lohrmann, E; Salehi, H; Schleper, P; Schörner-Sadenius, T; Sztuk, J; Wichmann, K; Wick, K; Foudas, C; Fry, C; Long, K R; Tapper, A D; Kataoka, M; Matsumoto, T; Nagano, K; Tokushuku, K; Yamada, S; Yamazaki, Y; Barakbaev, A N; Boos, E G; Pokrovskiy, N S; Zhautykov, B O; Aushev, V; Son, D; De Favereau, J; Piotrzkowski, K; Barreiro, F; Glasman, C; Jiménez, M; Labarga, L; Del Peso, J; Ron, E; Soares, M; Terron, J; Zambrana, M; Corriveau, F; Liu, C; Walsh, R; Zhou, C; Tsurugai, T; Antonov, A; Dolgoshein, B A; Sosnovtsev, V; Stifutkin, A; Suchkov, S; Dementiev, R K; Ermolov, P F; Gladilin, L K; Khein, L A; Korzhavina, I A; Kuzmin, V A; Levchenko, B B; Lukina, O Yu; Proskuryakov, A S; Shcheglova, L M; Zotkin, D S; Zotkin, S A; Abt, I; Büttner, C; Caldwell, A; Kollar, D; Schmidke, W B; Sutiak, J; Grigorescu, G; Keramidas, A; Koffeman, E; Kooijman, P; Pellegrino, A; Tiecke, H; Vázquez, M; Wiggers, L; Brümmer, N; Bylsma, B; Durkin, L S; Lee, A; Ling, T Y; Allfrey, P D; Bell, M A; Cooper-Sarkar, A M; Cottrell, A; Devenish, R C E; Foster, B; Korcsak-Gorzo, K; Patel, S; Roberfroid, V; Robertson, A; Straub, P B; Uribe-, C; Estrada; Walczak, R; Bellan, P; Bertolin, A; Brugnera, R; Carlin, R; Dal Corso, F; Dusini, S; Garfagnini, A; Limentani, S; Longhin, A; Stanco, L; Turcato, M; Oh, B Y; Raval, A; Ukleja, J; Whitmore, J J; Iga, Y; D'Agostini, G; Marini, G; Nigro, A; Cole, J E; Hart, J C; Abramowicz, H; Gabareen, A; Ingbir, R; Kananov, S; Levy, A; Kuze, M; Maeda, J; Hori, R; Kagawa, S; Okazaki, N; Shimizu, S; Tawara, T; Hamatsu, R; Kaji, H; Kitamura, S; Ota, O; Ri, Y D; Ferrero, M I; Monaco, V; Sacchi, R; Solano, A; Arneodo, M; Ruspa, M; Fourletov, S; Martin, J F; Boutle, S K; Butterworth, J M; Gwenlan, C; Jones, T W; Loizides, J H; Sutton, M R; Wing, M; Brzozowska, B; Ciborowski, J; Grzelak, G; Kulinski, P; Luzniak, P; Malka, J; Nowak, R J; Pawlak, J M; Tymieniecka, T; Ukleja, A; Zarnecki, A F; Adamus, M; Plucinsky, P P; Eisenberg, Y; Giller, I; Hochman, D; Karshon, U; Rosin, M; Brownson, E; Danielson, T; Everett, A; Kcira, D; Reeder, D D; Ryan, P; Savin, A A; Smith, W H; Wolfe, H; Bhadra, S; Catterall, C D; Cui, Y; Hartner, G; Menary, S; Noor, U; Standage, J; Whyte, J

    2007-01-01

    The first observation of (anti)deuterons in deep inelastic scattering at HERA has been made with the ZEUS detector at a centre-of-mass energy of 300--318 GeV using an integrated luminosity of 120 pb-1. The measurement was performed in the central rapidity region for transverse momentum per unit of mass in the range 0.3anti)proton yield by approximately three orders of magnitude, consistent with the world measurements.

  9. Expected Enhancement of the Primary Antiproton Flux at the Solar Minimum

    OpenAIRE

    Mitsui, T.; Maki, K.; Orito, S.

    1996-01-01

    We calculate the solar-modulated energy spectra of cosmic-ray antiprotons ($\\bar{p}$'s) from two candidate primary sources, i.e., evaporating primordial black holes and the annihilation of neutralino dark matter, as well as for the secondary $\\bar{p}$'s produced by cosmic-ray interactions with interstellar gas. A large enhancement toward the solar minimum phase emerges in the low-energy flux of $\\bar{p}$'s from the primary sources, whereas the flux of the secondary $\\bar{p}$'s, falling steepl...

  10. Antiproton-proton annihilations into four prongs at 7.2 GeV/c

    International Nuclear Information System (INIS)

    Annihilation reactions are described in which four charged pions and also maybe uncharged particles are produced. Data was acquired in an antiproton-proton experiment at a beam momentum of 7.2 GeV/c and 220K pictures of the CERN 2m HBC were measured. Cross sections have been determined and angular distributions of the pions and of some resonances are given. Two models that describe annihilation reactions are treated, the so called CLA model and a simple quark model. (C.F./Auth.)

  11. Effect of static electric field on cross sections in antiproton impact ionization of atomic helium

    International Nuclear Information System (INIS)

    We report the effect of static electric fields in different geometrical features on the collisional ionization of helium atoms by antiproton. The Classical Trajectory Monte Carlo (CTMC) method with a model interaction potential has been used to simulate the differential and total ionization cross sections in antiproton–helium atom collisions in the energy range of 10–500 keV with and without electric fields. The calculated ionization cross sections are in reasonable agreement with the recently reported experimental and theoretical results. The effects of the external electric fields are seen to be quite prominent.

  12. Antiproton--proton annihilation into pion pairs within effective meson theory

    CERN Document Server

    Wang, Ying; Tomasi-Gustafsson, Egle

    2015-01-01

    Antiproton--proton annihilation into light mesons is revisited in the few GeV energy domain, in view of a global description of the existing data. An effective meson model is developed, with mesonic and baryonic degrees od freedom in $s$, $t$, and $u$ channels. Regge factors are added to reproduce the proper energy behavior and the forward and backward peaked behavior. A comparison with existing data and predictions for angular distributions and energy dependence are done for charged and neutral pion pair production.

  13. Search For Magnetic Monopoles Possibly Produced By Proton-antiproton Collisions At The Tevatron Collider

    CERN Document Server

    Luo, W

    2002-01-01

    Magnetic monopoles can be used to explain the quantization of electric charge, and are predicted by gauge field theory. If monopoles exist, they could have been produced by the proton-antiproton collisions at the Tevatron collider—the highest energy accelerator existing in the world, and trapped in the CDF and DØ detectors. We took Al, Be, and Pb samples from the Tevatron and used the induction technique with SQUIDs (Superconducting Quantum Interference Devices) to detect monopoles in the samples. We did not find monopoles, but we have set new limits for the monopole mass and the relavant cross section based on a Drell-Yan model and Monte Carlo calculation.

  14. Measurements of the Ratio Between Double and Single Ionization of Helium for Antiprotons

    CERN Multimedia

    2002-01-01

    The inclusive spectra of @p|0's and @h's associated with @*p annihilation at rest are measured. Peaks in these spectra can be identified either with so far not explicitly observed two mesonic final states such as @p|0@w, @p|0@h, @h@h or @p|0@g, or with production of exotic mesonlike states such as baryonium. The apparatus is also suitable for searching for baryonium through some of its particular decay channels. As a by-product we expect information on direct @g production in @*p annihilations at rest.\\\\ \\\\ The apparatus consists of two modular BGO spectrometers and one array of leadglas detectors. The BGO spectrometers are adjustable in angle relative to each other and to the leadglas matrix, thus allowing to cover an angular range from 9|0 to 180|0, corresponding to momenta of zero to more than 1~GeV/c. The apparatus is designed such as to utilize the full potential of LEAR.

  15. Calculation of transition probabilities and ac Stark shifts in two-photon laser transitions of antiprotonic helium

    OpenAIRE

    HORI, MASAKI; Korobov, Vladimir I.

    2010-01-01

    Numerical ab initio variational calculations of the transition probabilities and ac Stark shifts in two-photon transitions of antiprotonic helium atoms driven by two counter-propagating laser beams are presented. We found that sub-Doppler spectroscopy is in principle possible by exciting transitions of the type (n,L)->(n-2,L-2) between antiprotonic states of principal and angular momentum quantum numbers n~L-1~35, first by using highly monochromatic, nanosecond laser beams of intensities 10^4...

  16. Ringed accretion disks: equilibrium configurations

    CERN Document Server

    Pugliese, D

    2015-01-01

    We investigate a model of ringed accretion disk, made up by several rings rotating around a supermassive Kerr black hole attractor. Each toroid of the ringed disk is governed by the General Relativity hydrodynamic Boyer condition of equilibrium configurations of rotating perfect fluids. Properties of the tori can be then determined by an appropriately defined effective potential reflecting the background Kerr geometry and the centrifugal effects. The ringed disks could be created in various regimes during the evolution of matter configurations around supermassive black holes. Therefore, both corotating and counterrotating rings have to be considered as being a constituent of the ringed disk. We provide constraints on the model parameters for the existence and stability of various ringed configurations and discuss occurrence of accretion onto the Kerr black hole and possible launching of jets from the ringed disk. We demonstrate that various ringed disks can be characterized by a maximum number of rings. We pr...

  17. Saturn's Other Ring Current

    Science.gov (United States)

    Crary, F. J.

    2014-04-01

    Saturn's main rings orbit the planet within an atmosphere and ionosphere of water, oxygen and hydrogen, produced by meteoritic impacts on and ultraviolet photodesorbtion of the ring particles [Johnson et al., 2006; Luhmann et al., 2006; Tseng et al., 2010]. The neutral atmosphere itself has only been tentatively detected through ultraviolet fluorescents of OH [Hall et al., 1996] while the ionosphere was observed in situ by the Cassini spacecraft shortly after orbital insertion [Coates et al.,2005; Tokar et al. 2005, Waite et al. 2005]. Although the plasma flow velocity of this ionosphere is not well-constrained, but the close association with the rings suggests that its speed would be couppled to the keplarian velocity of the rings themselves. As a result, the motion of the plasma through Saturn's magnetic field would produce an induced voltage, oriented away from the planet outside synchronous orbit and towards the planet inside synchronous orbit. Such a potential could result in currents flowing across the ring plane and closeing along magnetic field lines and through Saturn's ionosphere at latitudes between 36o and 48o. Cassini observations of whistler-mode plasma wave emissions [Xin et al.,2006] centered on synchronous orbit (1.76 Rs, mapping to 41o latitude) have been interpreted as a product of field-aligned electron beams associated with such a current. This presentation will investigate the magnitude of these currents and the resulting Joule heating of the ionosphere. An important constraint is that no auroral ultraviolet emissions have been observed at the relevant latitudes. In contrast, Joule heating could affect infrared emissions from H3+. Variations in H3+ emission associated with Saturn's rings have been reported by O'Donoghue et al., 2013, and interpreted as a result of ring "rain", i.e. precipitating water group species from the rings which alter ionosphereic chemistry and H3+ densities. As noted by O'Donoghue et al., this interpretation may be

  18. Physics of planetary rings

    Science.gov (United States)

    Gorkavyi, N.

    2007-08-01

    It is difficult to enumerate all the surprises presented by the planetary rings. The Saturnian rings are stratified into thousands of ringlets and the Uranian rings are compressed into narrow streams, which for some reason or other differ from circular orbits like the wheel of an old bicycle. The edge of the rings is jagged and the rings themselves are pegged down under the gravitational pressure of the satellites, bending like a ship's wake. There are spiral waves, elliptical rings, strange interlacing of narrow ringlets, and to cap it all one has observed in the Neptunian ring system three dense, bright arcs - like bunches of sausages on a transparent string. For celestial mechanics this is a spectacle as unnatural as a bear's tooth in the necklace of the English queen. In the dynamics of planetary rings the physics of collective interaction was supplemented by taking collisions between particles into account. One was led to study a kinetic equation with a rather complex collision integral - because the collisions are inelastic - which later on made it possible, both by using the Chapman-Enskog method and by using the solution of the kinetic equation for a plasma in a magnetic field, to reduce it to a closed set of (hydrodynamical) moment equations [1]. The hydrodynamical instabilities lead to the growth of short-wavelength waves and large-scale structures of the Saturnian rings [1]. We have shown that the formation of the existing dense Uranian rings is connected with the capture of positively drifting ring particles in inner Lindblad resonances which arrest this drift [1]. After the formation of dense rings at the positions of satellite resonances the collective interaction between resonant particles is amplified and the rings can leave the resonance and drift away from the planet and the parent resonance. We can expect in the C ring an appreciable positive ballistic particle drift caused by the erosion of the B ring by micrometeorites. It is therefore natural

  19. Rings dominate western Gulf

    Science.gov (United States)

    Vidal L., Francisco V.; Vidal L., Victor M. V.; Molero, José María Pérez

    Surface and deep circulation of the central and western Gulf of Mexico is controlled by interactions of rings of water pinched from the gulf's Loop Current. The discovery was made by Mexican oceanographers who are preparing a full-color, 8-volume oceanographic atlas of the gulf.Anticyclonic warm-core rings pinch off the Loop Current at a rate of about one to two per year, the scientists of the Grupo de Estudios Oceanográficos of the Instituto de Investigaciones Eléctricas (GEO-IIE) found. The rings migrate west until they collide with the continental shelf break of the western gulf, almost always between 22° and 23°N latitude. On their westward travel they transfer angular momentum and vorticity to the surrounding water, generating cyclonic circulations and vortex pairs that completely dominate the entire surface and deep circulation of the central and western gulf.

  20. Oligomeric ferrocene rings

    Science.gov (United States)

    Inkpen, Michael S.; Scheerer, Stefan; Linseis, Michael; White, Andrew J. P.; Winter, Rainer F.; Albrecht, Tim; Long, Nicholas J.

    2016-09-01

    Cyclic oligomers comprising strongly interacting redox-active monomer units represent an unknown, yet highly desirable class of nanoscale materials. Here we describe the synthesis and properties of the first family of molecules belonging to this compound category—differently sized rings comprising only 1,1‧-disubstituted ferrocene units (cyclo[n], n = 5–7, 9). Due to the close proximity and connectivity of centres (covalent Cp–Cp linkages; Cp = cyclopentadienyl) solution voltammograms exhibit well-resolved, separated 1e– waves. Theoretical interrogations into correlations based on ring size and charge state are facilitated using values of the equilibrium potentials of these transitions, as well as their relative spacing. As the interaction free energies between the redox centres scale linearly with overall ring charge and in conjunction with fast intramolecular electron transfer (∼107 s‑1), these molecules can be considered as uniformly charged nanorings (diameter ∼1–2 nm).

  1. Decay ring design

    CERN Document Server

    Chancé, A; Bouquerel, E; Hancock, S; Jensen, E

    The study of the neutrino oscillation between its different flavours needs pureand very intense fluxes of high energy, well collimated neutrinos with a welldetermined energy spectrum. A dedicated machine seems to be necessarynowadays to reach the required flux. A new concept based on the β-decayof radioactive ions which were accelerated in an accelerator chain was thenproposed. After ion production, stripping, bunching and acceleration, the unstableions are then stored in a racetrack-shaped superconducting decay ring.Finally, the ions are accumulated in the decay ring until being lost. The incomingbeam is merged to the stored beam by using a specific RF system, whichwill be presented here.We propose here to study some aspects of the decay ring, such as its opticalproperties, its RF system or the management of the losses which occur in thering (mainly by decay or by collimation).

  2. On Simple Noetherian Rings

    Institute of Scientific and Technical Information of China (English)

    Somyot Plubtieng

    2003-01-01

    A module M is called a CS-module (or extending module [5]) if every submodule of M is essential in a direct summand of M. It is shown that (i) a simple ring R is right noetherian if and only if every cyclic singular right R-module is either a CS-module or a noetherian module; (ii) for a prime ring R, if every proper cyclic right R-module is a direct sum of a quasi-injective module and a finitely cogenerated module, then R is either semisimple artinian or a right Ore domain; and (iii) a prime ring R is right noetherian if and only if every cyclic right R-module is a direct sum of a quasi-injective module and a noetherian module.

  3. Tunneling Through Black Rings

    Institute of Scientific and Technical Information of China (English)

    ZHAO Liu

    2007-01-01

    Hawking radiation of black ring solutions to 5-dimensional Einstein-Maxwell-dilaton theory is analyzed by use of the Parikh-Wilczek tunneling method. To get the correct tunneling amplitude and emission rate, we adopt and develop the Angheben-Nadalini-Vanzo-Zerbini covariant approach to cover the effects of rotation and electronic discharge all at once, and the effect of back reaction is also taken into account. This constitutes a unified approach to the tunneling problem. Provided the first law of thermodynamics for black rings holds, the emission rate is proportional to the exponential of the change of Bekenstein-Hawking entropy. Explicit calculation for black ring temperatures agrees exactly with the results obtained via the classical surface gravity method and the quasi-local formalism.

  4. Autocatalytic chemical smoke rings

    CERN Document Server

    Rogers, M C; Rogers, Michael C.; Morris, Stephen W.

    2005-01-01

    Buoyant plumes, evolving free of boundary constraints, may develop well-defined mushroom shaped heads. In normal plumes, overturning flow in the head entrains less buoyant fluid from the surroundings as the head rises, robbing the plume of its driving force. We consider here a new type of plume in which the source of buoyancy is an autocatalytic chemical reaction. The reaction occurs at a sharp front which separates reactants from less dense products. In this type of plume, entrainment assists the reaction, producing new buoyancy which fuels an accelerating plume head. When the head has grown to a critical size, it detaches from the upwelling conduit, forming an accelerating, buoyant vortex ring. This vortex is analogous to a rising smoke ring. A second-generation head then develops at the point of detachment.Multiple generations of chemical vortex rings can detach from a single triggering event.

  5. Almost ring theory

    CERN Document Server

    2003-01-01

    This book develops thorough and complete foundations for the method of almost etale extensions, which is at the basis of Faltings' approach to p-adic Hodge theory. The central notion is that of an "almost ring". Almost rings are the commutative unitary monoids in a tensor category obtained as a quotient V-Mod/S of the category V-Mod of modules over a fixed ring V; the subcategory S consists of all modules annihilated by a fixed ideal m of V, satisfying certain natural conditions. The reader is assumed to be familiar with general categorical notions, some basic commutative algebra and some advanced homological algebra (derived categories, simplicial methods). Apart from these general prerequisites, the text is as self-contained as possible. One novel feature of the book - compared with Faltings' earlier treatment - is the systematic exploitation of the cotangent complex, especially for the study of deformations of almost algebras.

  6. High precision spectroscopy of pionic and antiprotonic atoms; Spectroscopie de precision des atomes pioniques et antiprotoniques

    Energy Technology Data Exchange (ETDEWEB)

    El-Khoury, P

    1998-04-15

    The study of exotic atoms, in which an orbiting electron of a normal atom is replaced by a negatively charged particle ({pi}{sup -}, {mu}{sup -}, p, {kappa}{sup -}, {sigma}{sup -},...) may provide information on the orbiting particle and the atomic nucleus, as well as on their interaction. In this work, we were interested in pionic atoms ({pi}{sup -14} N) on the one hand in order to determine the pion mass with high accuracy (4 ppm), and on the other hand in antiprotonic atoms (pp-bar) in order to study the strong nucleon-antinucleon interaction at threshold. In this respect, a high-resolution crystal spectrometer was coupled to a cyclotron trap which provides a high stop density for particles in gas targets at low pressure. Using curved crystals, an extended X-ray source could be imaged onto the detector. Charge-Coupled Devices were used as position sensitive detectors in order to measure the Bragg angle of the transition to a high precision. The use of gas targets resolved the ambiguity owing to the number of K electrons for the value of the pion mass, and, for the first time, strong interaction shift and broadening of the 2p level in antiprotonic hydrogen were measured directly. (author)

  7. Antiproton and positron signal enhancement in dark matter mini-spikes scenarios

    International Nuclear Information System (INIS)

    The annihilation of dark matter (DM) in the Galaxy could produce specific imprints on the spectra of antimatter species in Galactic cosmic rays, which could be detected by upcoming experiments such as PAMELA and AMS02. Recent studies show that the presence of substructures can enhance the annihilation signal by a 'boost factor' that not only depends on energy, but that is intrinsically a statistical property of the distribution of DM substructures inside the Milky Way. We investigate a scenario in which substructures consist of ∼100 'mini-spikes' around intermediate-mass black holes. Focusing on primary positrons and antiprotons, we find large boost factors, up to a few thousand, that exhibit a large variance at high energy in the case of positrons and at low energy in the case of antiprotons. As a consequence, an estimate of the DM particle mass based on the observed cut-off in the positron spectrum could lead to a substantial underestimate of its actual value. (authors)

  8. A possible dark matter annihilation signal in the AMS-02 antiproton data

    CERN Document Server

    Cui, Ming-Yang; Tsai, Yue-Lin Sming; Fan, Yi-Zhong

    2016-01-01

    A new approach has been adopted to probe the dark matter signal using the latest AMS-02 cosmic ray antiproton flux data. Different from previous studies, we do not assume specific propagation, injection, and solar modulation parameters when calculating the antiproton fluxes, but use the results inferred from the B/C ratio and proton data from the recent PAMELA/AMS-02 measurements instead. A joint likelihood method including the likelihood of these background parameters is established within the Bayesian framework. We find that a dark matter signal is favored with a high test statistic value of $\\sim 70$. The rest mass of the dark matter particles is $\\sim 30-70$ GeV and the velocity-averaged hadronic annihilation cross section is about $(1-6)\\times 10^{-26}$ cm$^{3}$s$^{-1}$, in agreement with that needed to account for the Galactic center GeV excess and/or the weak GeV emission from dwarf galaxies Reticulum 2 and Tucana III. Tight constraints on the dark matter annihilation models are also set in a wide mass...

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

    CERN Document Server

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

    2016-01-01

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

  10. Antiproton beam parameters measurement by a new digital-receiver-based system

    CERN Document Server

    Angoletta, Maria Elena; Chohan, V; Findlay, A; Ludwig, M; Marqversen, O; Pedersen, F

    2001-01-01

    The Antiproton Decelerator (AD) provides the users with very low intensity beams, in the 107 particles range, hence prompting the development of an innovative measuring system, which was completed in early 2000. This system measures antiproton beam intensity for bunched and debunched beams, together with momentum spread and mean momentum for debunched beams. It uses a state-of-the-art Digital Receiver board, which processes data obtained from two ultra-low-noise, wide-band AC beam transformers. These have a combined bandwidth in the range 0.02 MHz - 30 MHz and are used to measure AC beam current modulation. For bunched beams, the intensity is obtained by measuring the amplitude of the fundamental and second RF Fourier components. On the magnetic plateaus the beam is debunched for stochastic or electron cooling and longitudinal beam properties (intensity, momentum spread and mean momentum) are measured by FFT-based spectral analysis of Schottky signals. The system provides real-time information characterising ...

  11. High intensity proton injector for facility of antiproton and ion research

    Energy Technology Data Exchange (ETDEWEB)

    Berezov, R., E-mail: r.berezov@gsi.de; Brodhage, R.; Fils, J.; Hollinger, R.; Ivanova, V. [GSI Helmholtzzentrum für Schwerionenforschung GmbH, Planckstr. 1, 64291 Darmstadt (Germany); Chauvin, N.; Delferriere, O.; Tuske, O. [Commissariat à l’Energie Atomique et aux Energies Alternatives, IRFU, F-91191 Gif-sur-Yvette (France); Ullmann, C. [GSI Helmholtzzentrum für Schwerionenforschung GmbH, Planckstr. 1, 64291 Darmstadt (Germany); Institut für Angewandte Physik, Goethe-Universität Frankfurt, Max-von-Laue-Str. 1, 60438 Frankfurt/Main (Germany)

    2016-02-15

    The high current ion source with the low energy beam transport (LEBT) will serve as injector into the proton LINAC to provide primary proton beam for the production of antiprotons. The pulsed ion source developed and built in CEA/Saclay operates with a frequency of 2.45 GHz based on ECR plasma production with two coils with 87.5 mT magnetic field necessary for the electron cyclotron resonance. The compact LEBT consists of two solenoids with a maximum magnetic field of 500 mT including two integrated magnetic steerers to adjust the horizontal and vertical beam positions. The total length of the compact LEBT is 2.3 m and was made as short as possible to reduced emittance growth along the beam line. To measure ion beam intensity behind the pentode extraction system, between solenoids and at the end of the beam line, two current transformers and a Faraday cup are installed. To get information about the beam quality and position, the diagnostic chamber with different equipment will be installed between the two solenoids. This article reports the current status of the proton injector for the facility of antiproton and ion research.

  12. Meas.of the Ratio Between Double and Single Ionization of Helium for Antiprotons

    CERN Multimedia

    2002-01-01

    The aim of this experiment is to measure the ratio between double and single ionization of helium by antiprotons in the energy range $>$~3~MeV. Comparison with already existing proton data will yield information on the mechanisms for double ionization, which could not be extracted from previous comparisons between ratios measured for equivelocity electrons and protons. The most basic information to be obtained from an antiproton experiment will be the amount of correlation existing between the two electrons in the ground-state helium atom.\\\\ \\\\ The equipment consists of a gas cell, which employs slow-ion collection via the so-called condenser-plate method for the absolute sum of partial-ionization cross sections and determination of the relative contribution of multiple charged ions by TOF. The gas cell has movable entrance and exit slits and a grid system to account for secondary emission from the collection of slow ions. Together with a field of 800~V/cm in the collision region, the potentials of the TOF sp...

  13. GAPS - Dark matter search with low-energy cosmic-ray antideuterons and antiprotons

    CERN Document Server

    von Doetinchem, P; Boggs, S; Fuke, H; Hailey, C J; Mognet, S I; Ong, R A; Perez, K; Zweerink, J

    2015-01-01

    The GAPS experiment is foreseen to carry out a dark matter search by measuring low-energy cosmic-ray antideuterons and antiprotons with a novel detection approach. It will provide a new avenue to access a wide range of different dark matter models and masses from about 10GeV to 1TeV. The theoretically predicted antideuteron flux resulting from secondary interactions of primary cosmic rays is very low. Well-motivated theories beyond the Standard Model contain viable dark matter candidates, which could lead to a significant enhancement of the antideuteron flux due to annihilation or decay of dark matter particles. This flux contribution is believed to be especially large at low energies, which leads to a high discovery potential for GAPS. The GAPS low-energy antiproton search will provide some of the most stringent constraints on ~30GeV dark matter, will provide the best limits on primordial black hole evaporation on galactic length scales, and explore new discovery space in cosmic-ray physics. GAPS is designed...

  14. ${\\bar D}D$ meson pair production in antiproton-nucleus collisions

    CERN Document Server

    Shyam, R

    2016-01-01

    We study the $\\bar D D$ (${\\bar D}^0 D^0$ and $D^-D^+$) charm meson pair production in antiproton (${\\bar p}$) induced reactions on nuclei at beam energies ranging from threshold to several GeV. Our model is based on an effective Lagrangian approach that has only the baryon-meson degrees of freedom and involves the physical hadron masses. The reaction proceeds via the $t$-channel exchanges of $\\Lambda_c^+$, $\\Sigma_c^+$, and $\\Sigma_c^{++}$ baryons in the initial collision of the antiproton with one of the protons of the target nucleus. The medium effects on the exchanged baryons are included by incorporating in the corresponding propagators, the effective charm baryon masses calculated within a quark-meson coupling (QMC) model. The wave functions of the bound proton have been determined within the QMC model as well as in a phenomenological model where they are obtained by solving the Dirac equation with appropriate scalar and vector potentials. The initial- and final-state distortion effects have been approx...

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

    Science.gov (United States)

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

    2016-07-01

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

  16. Novel dark matter constraints from antiprotons in the light of AMS-02

    CERN Document Server

    Cuoco, Alessandro; Korsmeier, Michael

    2016-01-01

    We evaluate dark matter (DM) limits from cosmic-ray antiproton observations using the recent precise AMS-02 measurements. We properly take into account cosmic-ray propagation uncertainties fitting at the same time DM and propagation parameters, and marginalizing over the latter. We find a significant (~4.5 sigma) indication of a DM signal for DM masses near 80 GeV, with a hadronic annihilation cross-section close to the thermal value, sigma v ~3e-26 cm3s-1. Intriguingly, this signal is compatible with the DM interpretation of the Galactic center gamma-ray excess. Confirmation of the signal will require a more accurate study of the systematic uncertainties, i.e., the antiproton production cross-section, and modelling of the solar modulation effect. Interpreting the AMS-02 data in terms of upper limits on hadronic DM annihilation, we obtain strong constraints excluding a thermal annihilation cross-section for DM masses below about 50 GeV and in the range between approximately 150 and 500 GeV, even for conservat...

  17. Measurement of the Antiproton-Proton Total Cross-Section at the CERN ISR

    CERN Multimedia

    2002-01-01

    This experiment is a measurement of small angle scattering of antiprotons on protons and of protons on protons at 15/15, 22/22, 26/26 and 31/31 GeV, with the aim of obtaining data on the total cross-section for the scattering of protons on protons, and of determining the ratio of the real to the imaginary scattering amplitude at zero momentum transfer for antiprotons on protons. The measurement is divided into two parts: \\item 1) The measurement of @s^t^o^t(@*p) and @s^t^o^t(pp), using hodoscopes placed at small angles, outside the vacuum pipe, at approximately 9 metres from the intersection point. \\item 2) The measurement of the region in !t!, the momentum transfer squared, around the value !t^c!, where Coulomb and nuclear scattering are equal, in order to deduce the quantity @r = Re f(t=0)/Im f(t=0). This latter measurement is done by employi in earlier @s^t(pp) and @r experiments at the ISR. \\end{enumerate} In both set-ups the measurements are made by recording coincidences between collinear counters in th...

  18. Search for Resonances in the Photoproduction of Proton-Antiproton Pairs

    Energy Technology Data Exchange (ETDEWEB)

    Burnham Stokes

    2006-06-30

    Results are reported on the reaction {gamma}p {yields} p{bar p}p with beam energy in the range 4.8-5.5 GeV. The data were collected at the Thomas Jefferson National Accelerator Facility in CLAS experiment E01-017(G6C). The focus of this study is an understanding of the mechanisms of photoproduction of proton-antiproton pairs, and to search for intermediate resonances, both narrow and broad, which decay to p{bar p}. The total measured cross section in the photon energy range 4.8-5.5 GeV is {sigma} = 33 {+-} 2 nb. Measurement of the cross section as a function of energy is provided. An upper limit on the production of a narrow resonance state previously observed with a mass of 2.02 GeV/c{sup 2} is placed at 0.35 nb. No intermediate resonance states were observed. Meson exchange production appears to dominate the production of the proton-antiproton pairs.

  19. Den mindst ringe verdensorden

    DEFF Research Database (Denmark)

    Hansen, Birthe

    2015-01-01

    I 25 år har USA's styrkeposition og politik forsynet os med en 'verdensorden', der i et historisk perspektiv fremstår som den mindst ringe: fravær af store krige, mere demokrati, økonomisk fremgang - men dog også sammenbrudte stater og terrorisme.......I 25 år har USA's styrkeposition og politik forsynet os med en 'verdensorden', der i et historisk perspektiv fremstår som den mindst ringe: fravær af store krige, mere demokrati, økonomisk fremgang - men dog også sammenbrudte stater og terrorisme....

  20. On toric face rings

    OpenAIRE

    Ichim, Bogdan; Roemer, Tim

    2006-01-01

    Following a construction of Stanley we consider toric face rings associated to rational pointed fans. This class of rings is a common generalization of the concepts of Stanley--Reisner and affine monoid algebras. The main goal of this article is to unify parts of the theories of Stanley--Reisner- and affine monoid algebras. We consider (non-pure) shellable fan's and the Cohen--Macaulay property. Moreover, we study the local cohomology, the canonical module and the Gorenstein property of a tor...

  1. Ringed accretion disks: instabilities

    CERN Document Server

    Pugliese, D

    2016-01-01

    We analyze the possibility that several instability points may be formed, due to the Paczy\\'nski mechanism of violation of mechanical equilibrium, in the orbiting matter around a supermassive Kerr black hole. We consider recently proposed model of ringed accretion disk, made up by several tori (rings) which can be corotating or counterrotating relative to the Kerr attractor due to the history of the accretion process. Each torus is governed by the general relativistic hydrodynamic Boyer condition of equilibrium configurations of rotating perfect fluids. We prove that the number of the instability points is generally limited and depends on the dimensionless spin of the rotating attractor.

  2. Unidirectional ring lasers

    Science.gov (United States)

    Hohimer, J.P.; Craft, D.C.

    1994-09-20

    Unidirectional ring lasers formed by integrating nonreciprocal optical elements into the resonant ring cavity is disclosed. These optical elements either attenuate light traveling in a nonpreferred direction or amplify light traveling in a preferred direction. In one preferred embodiment the resonant cavity takes the form of a circle with an S-shaped crossover waveguide connected to two points on the interior of the cavity such that light traveling in a nonpreferred direction is diverted from the cavity into the crossover waveguide and reinjected out of the other end of the crossover waveguide into the cavity as light traveling in the preferred direction. 21 figs.

  3. The covariant chiral ring

    Science.gov (United States)

    Bourget, Antoine; Troost, Jan

    2016-03-01

    We construct a covariant generating function for the spectrum of chiral primaries of symmetric orbifold conformal field theories with N = (4 , 4) supersymmetry in two dimensions. For seed target spaces K3 and T 4, the generating functions capture the SO(21) and SO(5) representation theoretic content of the chiral ring respectively. Via string dualities, we relate the transformation properties of the chiral ring under these isometries of the moduli space to the Lorentz covariance of perturbative string partition functions in flat space.

  4. The Covariant Chiral Ring

    CERN Document Server

    Bourget, Antoine

    2015-01-01

    We construct a covariant generating function for the spectrum of chiral primaries of symmetric orbifold conformal field theories with N=(4,4) supersymmetry in two dimensions. For seed target spaces K3 and T4, the generating functions capture the SO(21) and SO(5) representation theoretic content of the chiral ring respectively. Via string dualities, we relate the transformation properties of the chiral ring under these isometries of the moduli space to the Lorentz covariance of perturbative string partition functions in flat space.

  5. Electrothermal Ring Burn

    OpenAIRE

    Yakup Çil; Hamza Yıldız; Özlem Karabudak Abuaf

    2012-01-01

    Low-voltage fountainheads such as car, tractor or motorcycle batteries are predisposed to produce large currents. Any metal object that comes into contact with these batteries may result in short-circuit. This may result in rapid and excessive heating of metal object and an electrothermal burn. Herein we presented a motorcycle driver who was 28-year-old man with electrothermal ring burn which was caused by metal chain that was used as a ring. (Turk J Dermatol 2012; 6: 106-7)

  6. Electrothermal Ring Burn

    Directory of Open Access Journals (Sweden)

    Yakup Çil

    2012-09-01

    Full Text Available Low-voltage fountainheads such as car, tractor or motorcycle batteries are predisposed to produce large currents. Any metal object that comes into contact with these batteries may result in short-circuit. This may result in rapid and excessive heating of metal object and an electrothermal burn. Herein we presented a motorcycle driver who was 28-year-old man with electrothermal ring burn which was caused by metal chain that was used as a ring. (Turk J Dermatol 2012; 6: 106-7

  7. Antiproton Flux, Antiproton-to-Proton Flux Ratio, and Properties of Elementary Particle Fluxes in Primary Cosmic Rays Measured with the Alpha Magnetic Spectrometer on the International Space Station.

    Science.gov (United States)

    Aguilar, M; Ali Cavasonza, L; Alpat, B; Ambrosi, G; Arruda, L; Attig, N; Aupetit, S; Azzarello, P; Bachlechner, A; Barao, F; Barrau, A; Barrin, L; Bartoloni, A; Basara, L; Başeǧmez-du Pree, S; Battarbee, M; Battiston, R; Bazo, J; Becker, U; Behlmann, M; Beischer, B; Berdugo, J; Bertucci, B; Bindi, V; Boella, G; de Boer, W; Bollweg, K; Bonnivard, V; Borgia, B; Boschini, M J; Bourquin, M; Bueno, E F; Burger, J; Cadoux, F; Cai, X D; Capell, M; Caroff, S; Casaus, J; Castellini, G; Cernuda, I; Cervelli, F; Chae, M J; Chang, Y H; Chen, A I; Chen, G M; Chen, H S; Cheng, L; Chou, H Y; Choumilov, E; Choutko, V; Chung, C H; Clark, C; Clavero, R; Coignet, G; Consolandi, C; Contin, A; Corti, C; Coste, B; Creus, W; Crispoltoni, M; Cui, Z; Dai, Y M; Delgado, C; Della Torre, S; Demirköz, M B; Derome, L; Di Falco, S; Dimiccoli, F; Díaz, C; von Doetinchem, P; Dong, F; Donnini, F; Duranti, M; D'Urso, D; Egorov, A; Eline, A; Eronen, T; Feng, J; Fiandrini, E; Finch, E; Fisher, P; Formato, V; Galaktionov, Y; Gallucci, G; García, B; García-López, R J; Gargiulo, C; Gast, H; Gebauer, I; Gervasi, M; Ghelfi, A; Giovacchini, F; Goglov, P; Gómez-Coral, D M; Gong, J; Goy, C; Grabski, V; Grandi, D; Graziani, M; Guerri, I; Guo, K H; Habiby, M; Haino, S; Han, K C; He, Z H; Heil, M; Hoffman, J; Hsieh, T H; Huang, H; Huang, Z C; Huh, C; Incagli, M; Ionica, M; Jang, W Y; Jinchi, H; Kang, S C; Kanishev, K; Kim, G N; Kim, K S; Kirn, Th; Konak, C; Kounina, O; Kounine, A; Koutsenko, V; Krafczyk, M S; La Vacca, G; Laudi, E; Laurenti, G; Lazzizzera, I; Lebedev, A; Lee, H T; Lee, S C; Leluc, C; Li, H S; Li, J Q; Li, J Q; Li, Q; Li, T X; Li, W; Li, Z H; Li, Z Y; Lim, S; Lin, C H; Lipari, P; Lippert, T; Liu, D; Liu, Hu; Lu, S Q; Lu, Y S; Luebelsmeyer, K; Luo, F; Luo, J Z; Lv, S S; Majka, R; Mañá, C; Marín, J; Martin, T; Martínez, G; Masi, N; Maurin, D; Menchaca-Rocha, A; Meng, Q; Mo, D C; Morescalchi, L; Mott, P; Nelson, T; Ni, J Q; Nikonov, N; Nozzoli, F; Nunes, P; Oliva, A; Orcinha, M; Palmonari, F; Palomares, C; Paniccia, M; Pauluzzi, M; Pensotti, S; Pereira, R; Picot-Clemente, N; Pilo, F; Pizzolotto, C; Plyaskin, V; Pohl, M; Poireau, V; Putze, A; Quadrani, L; Qi, X M; Qin, X; Qu, Z Y; Räihä, T; Rancoita, P G; Rapin, D; Ricol, J S; Rodríguez, I; Rosier-Lees, S; Rozhkov, A; Rozza, D; Sagdeev, R; Sandweiss, J; Saouter, P; Schael, S; Schmidt, S M; Schulz von Dratzig, A; Schwering, G; Seo, E S; Shan, B S; Shi, J Y; Siedenburg, T; Son, D; Song, J W; Sun, W H; Tacconi, M; Tang, X W; Tang, Z C; Tao, L; Tescaro, D; Ting, Samuel C C; Ting, S M; Tomassetti, N; Torsti, J; Türkoğlu, C; Urban, T; Vagelli, V; Valente, E; Vannini, C; Valtonen, E; Vázquez Acosta, M; Vecchi, M; Velasco, M; Vialle, J P; Vitale, V; Vitillo, S; Wang, L Q; Wang, N H; Wang, Q L; Wang, X; Wang, X Q; Wang, Z X; Wei, C C; Weng, Z L; Whitman, K; Wienkenhöver, J; Willenbrock, M; Wu, H; Wu, X; Xia, X; Xiong, R Q; Xu, W; Yan, Q; Yang, J; Yang, M; Yang, Y; Yi, H; Yu, Y J; Yu, Z Q; Zeissler, S; Zhang, C; Zhang, J; Zhang, J H; Zhang, S D; Zhang, S W; Zhang, Z; Zheng, Z M; Zhu, Z Q; Zhuang, H L; Zhukov, V; Zichichi, A; Zimmermann, N; Zuccon, P

    2016-08-26

    A precision measurement by AMS of the antiproton flux and the antiproton-to-proton flux ratio in primary cosmic rays in the absolute rigidity range from 1 to 450 GV is presented based on 3.49×10^{5} antiproton events and 2.42×10^{9} proton events. The fluxes and flux ratios of charged elementary particles in cosmic rays are also presented. In the absolute rigidity range ∼60 to ∼500  GV, the antiproton p[over ¯], proton p, and positron e^{+} fluxes are found to have nearly identical rigidity dependence and the electron e^{-} flux exhibits a different rigidity dependence. Below 60 GV, the (p[over ¯]/p), (p[over ¯]/e^{+}), and (p/e^{+}) flux ratios each reaches a maximum. From ∼60 to ∼500  GV, the (p[over ¯]/p), (p[over ¯]/e^{+}), and (p/e^{+}) flux ratios show no rigidity dependence. These are new observations of the properties of elementary particles in the cosmos. PMID:27610839

  8. Antiproton Flux, Antiproton-to-Proton Flux Ratio, and Properties of Elementary Particle Fluxes in Primary Cosmic Rays Measured with the Alpha Magnetic Spectrometer on the International Space Station

    Science.gov (United States)

    Aguilar, M.; Ali Cavasonza, L.; Alpat, B.; Ambrosi, G.; Arruda, L.; Attig, N.; Aupetit, S.; Azzarello, P.; Bachlechner, A.; Barao, F.; Barrau, A.; Barrin, L.; Bartoloni, A.; Basara, L.; Başeǧmez-du Pree, S.; Battarbee, M.; Battiston, R.; Bazo, J.; Becker, U.; Behlmann, M.; Beischer, B.; Berdugo, J.; Bertucci, B.; Bindi, V.; Boella, G.; de Boer, W.; Bollweg, K.; Bonnivard, V.; Borgia, B.; Boschini, M. J.; Bourquin, M.; Bueno, E. F.; Burger, J.; Cadoux, F.; Cai, X. D.; Capell, M.; Caroff, S.; Casaus, J.; Castellini, G.; Cernuda, I.; Cervelli, F.; Chae, M. J.; Chang, Y. H.; Chen, A. I.; Chen, G. M.; Chen, H. S.; Cheng, L.; Chou, H. Y.; Choumilov, E.; Choutko, V.; Chung, C. H.; Clark, C.; Clavero, R.; Coignet, G.; Consolandi, C.; Contin, A.; Corti, C.; Coste, B.; Creus, W.; Crispoltoni, M.; Cui, Z.; Dai, Y. M.; Delgado, C.; Della Torre, S.; Demirköz, M. B.; Derome, L.; Di Falco, S.; Dimiccoli, F.; Díaz, C.; von Doetinchem, P.; Dong, F.; Donnini, F.; Duranti, M.; D'Urso, D.; Egorov, A.; Eline, A.; Eronen, T.; Feng, J.; Fiandrini, E.; Finch, E.; Fisher, P.; Formato, V.; Galaktionov, Y.; Gallucci, G.; García, B.; García-López, R. J.; Gargiulo, C.; Gast, H.; Gebauer, I.; Gervasi, M.; Ghelfi, A.; Giovacchini, F.; Goglov, P.; Gómez-Coral, D. M.; Gong, J.; Goy, C.; Grabski, V.; Grandi, D.; Graziani, M.; Guerri, I.; Guo, K. H.; Habiby, M.; Haino, S.; Han, K. C.; He, Z. H.; Heil, M.; Hoffman, J.; Hsieh, T. H.; Huang, H.; Huang, Z. C.; Huh, C.; Incagli, M.; Ionica, M.; Jang, W. Y.; Jinchi, H.; Kang, S. C.; Kanishev, K.; Kim, G. N.; Kim, K. S.; Kirn, Th.; Konak, C.; Kounina, O.; Kounine, A.; Koutsenko, V.; Krafczyk, M. S.; La Vacca, G.; Laudi, E.; Laurenti, G.; Lazzizzera, I.; Lebedev, A.; Lee, H. T.; Lee, S. C.; Leluc, C.; Li, H. S.; Li, J. Q.; Li, J. Q.; Li, Q.; Li, T. X.; Li, W.; Li, Z. H.; Li, Z. Y.; Lim, S.; Lin, C. H.; Lipari, P.; Lippert, T.; Liu, D.; Liu, Hu; Lu, S. Q.; Lu, Y. S.; Luebelsmeyer, K.; Luo, F.; Luo, J. Z.; Lv, S. S.; Majka, R.; Mañá, C.; Marín, J.; Martin, T.; Martínez, G.; Masi, N.; Maurin, D.; Menchaca-Rocha, A.; Meng, Q.; Mo, D. C.; Morescalchi, L.; Mott, P.; Nelson, T.; Ni, J. Q.; Nikonov, N.; Nozzoli, F.; Nunes, P.; Oliva, A.; Orcinha, M.; Palmonari, F.; Palomares, C.; Paniccia, M.; Pauluzzi, M.; Pensotti, S.; Pereira, R.; Picot-Clemente, N.; Pilo, F.; Pizzolotto, C.; Plyaskin, V.; Pohl, M.; Poireau, V.; Putze, A.; Quadrani, L.; Qi, X. M.; Qin, X.; Qu, Z. Y.; Räihä, T.; Rancoita, P. G.; Rapin, D.; Ricol, J. S.; Rodríguez, I.; Rosier-Lees, S.; Rozhkov, A.; Rozza, D.; Sagdeev, R.; Sandweiss, J.; Saouter, P.; Schael, S.; Schmidt, S. M.; Schulz von Dratzig, A.; Schwering, G.; Seo, E. S.; Shan, B. S.; Shi, J. Y.; Siedenburg, T.; Son, D.; Song, J. W.; Sun, W. H.; Tacconi, M.; Tang, X. W.; Tang, Z. C.; Tao, L.; Tescaro, D.; Ting, Samuel C. C.; Ting, S. M.; Tomassetti, N.; Torsti, J.; Türkoǧlu, C.; Urban, T.; Vagelli, V.; Valente, E.; Vannini, C.; Valtonen, E.; Vázquez Acosta, M.; Vecchi, M.; Velasco, M.; Vialle, J. P.; Vitale, V.; Vitillo, S.; Wang, L. Q.; Wang, N. H.; Wang, Q. L.; Wang, X.; Wang, X. Q.; Wang, Z. X.; Wei, C. C.; Weng, Z. L.; Whitman, K.; Wienkenhöver, J.; Willenbrock, M.; Wu, H.; Wu, X.; Xia, X.; Xiong, R. Q.; Xu, W.; Yan, Q.; Yang, J.; Yang, M.; Yang, Y.; Yi, H.; Yu, Y. J.; Yu, Z. Q.; Zeissler, S.; Zhang, C.; Zhang, J.; Zhang, J. H.; Zhang, S. D.; Zhang, S. W.; Zhang, Z.; Zheng, Z. M.; Zhu, Z. Q.; Zhuang, H. L.; Zhukov, V.; Zichichi, A.; Zimmermann, N.; Zuccon, P.; AMS Collaboration

    2016-08-01

    A precision measurement by AMS of the antiproton flux and the antiproton-to-proton flux ratio in primary cosmic rays in the absolute rigidity range from 1 to 450 GV is presented based on 3.49 ×1 05 antiproton events and 2.42 ×1 09 proton events. The fluxes and flux ratios of charged elementary particles in cosmic rays are also presented. In the absolute rigidity range ˜60 to ˜500 GV , the antiproton p ¯, proton p , and positron e+ fluxes are found to have nearly identical rigidity dependence and the electron e- flux exhibits a different rigidity dependence. Below 60 GV, the (p ¯/p ), (p ¯/e+), and (p /e+) flux ratios each reaches a maximum. From ˜60 to ˜500 GV , the (p ¯/p ), (p ¯/e+), and (p /e+) flux ratios show no rigidity dependence. These are new observations of the properties of elementary particles in the cosmos.

  9. Antineutron-nucleus annihilation

    CERN Document Server

    Botta, E

    2001-01-01

    The n-nucleus annihilation process has been studied by the OBELIX experiment at the CERN Low Energy Antiproton Ring (LEAR) in the (50-400) MeV/c projectile momentum range on C, Al, Cu, Ag, Sn, and Pb nuclear targets. A systematic survey of the annihilation cross- section, sigma /sub alpha /(A, p/sub n/), has been performed, obtaining information on its dependence on the target mass number and on the incoming n momentum. For the first time the mass number dependence of the (inclusive) final state composition of the process has been analyzed. Production of the rho vector meson has also been examined. (13 refs).

  10. AD performance and its extension towards ELENA

    International Nuclear Information System (INIS)

    The CERN’s Antiproton Decelerator (AD) is devoted to special experiments with low energy antiprotons. A main topic is the antihydrogen production with the present aim to produce these antimatter atoms with such low energy that they can be trapped in a magnetic gradient field. First very convincing results have been published recently by ALPHA. Still, it appears to be cumbersome, time consuming and ineffective when collecting the needed large numbers and high densities of antiproton clouds with the present AD. Both the effectiveness and the availability for additional experiments at this unique facility would drastically increase, if the antiproton beam of presently 5 MeV kinetic energy would be reduced by an additional decelerator to something like 100 keV. Such a facility ”ELENA”, as an abbreviation for Extra Low ENergy Antiproton Ring and first discussed in 1982 for LEAR, was freshly proposed with a substantial new design and revised layout and is presently under consideration. ELENA will increase the number of useful antiprotons by up to two orders of magnitude and will allow to serve up to four experiments in parallel.

  11. Flushing Ring for EDM

    Science.gov (United States)

    Earwood, L.

    1985-01-01

    Removing debris more quickly lowers cutting time. Operation, cutting oil and pressurized air supplied to ring placed around workpiece. Air forces oil through small holes and agitates oil as it flows over workpiece. High flow rate and agitation dislodge and remove debris. Electrical discharge removes material from workpiece faster.

  12. Deceleration of MeV antiprotons and muons to keV energies — the anticyclotron A progress report

    Science.gov (United States)

    Horváth, D.; Aschenauer, E. C.; Cauz, D.; Chatellard, D.; DeCecco, P.; Eades, J.; Egger, J.-P.; Elsener, K.; Eugster, P.; Formisano, F.; Gorini, G.; Hauser, P.; Kottmann, F.; Krafcsik, I.; Lagomarsino, V.; Manuzio, G.; Missimer, J.; Poggiani, R.; Simons, L. M.; Testera, G.; Torelli, G.; Waldner, F.

    1994-03-01

    A progress report is presented on the development of the anticyclotron — deceleration of antiprotons and negative muons via collisions in a low-pressure gas or thin foils during revolutions in a cyclotron field. Beam tests performed at CERN and PSI are reported and future plans for applications outlined.

  13. Deceleration of MeV antiprotons and muons to keV energies - the anticyclotron. A progress report

    Energy Technology Data Exchange (ETDEWEB)

    Horvath, D.; Aschenauer, E.C.; Cauz, D.; Chatellard, D.; DeCecco, P.; Eades, J.; Egger, J.P.; Elsener, K.; Eugster, P.; Formisano, F.; Gorini, G.; Hauser, P.; Kottmann, F.; Krafcsik, I.; Lagomarsino, V.; Manuzio, G.; Missimer, J.; Poggiani, R.; Simons, L.M.; Testera, G.; Torelli, G.; Waldner, F. (KFKI Research Inst. for Particle and Nuclear Physics, Budapest (Hungary) Pisa Univ. (Italy) INFN, Pisa (Italy) Paul Scherrer Inst., Villigen (Switzerland) Univ. di Udine (Italy) Neuchatel Univ. (Switzerland) CERN, Geneva (Switzerland) ETH Zuerich, Villigen (Switzerland) KFKI Research Inst. for Materials Science, Budapest (Hungary) Genova Univ. (Italy) INFN, Genova (Italy))

    1994-03-01

    A progress report is presented on the development of the anticyclotron - deceleration of antiprotons and negative muons via collisions in a low-pressure gas or thin foils during revolutions in a cyclotron field. Beam tests performed at CERN and PSI are reported and future plans for applications outlined. (orig.)

  14. Non-dissociative and dissociative ionisation of H sub 2 by 50-2000 keV antiprotons

    Energy Technology Data Exchange (ETDEWEB)

    Andersen, L.H.; Hvelplund, P.; Knudsen, H.; Moeller, S.P.; Pedersen, J.O.P.; Tang-Petersen, S.; Uggerhoej, E. (Aarhus Univ. (Denmark). Inst. of Physics); Elsener, K. (European Organization for Nuclear Research, Geneva (Switzerland)); Morenzoni, E. (Paul Scherrer Inst. (PSI), Villigen (Switzerland))

    1990-08-14

    A beam of antiprotons with energies between 50 keV and 2 MeV has been used for measurements of non-dissociative ionisation and dissociative ionisation cross sections of H{sub 2}. The results are compared with cross sections for equivelocity protons and electrons, and the role of interference effects in two-electron processes is discussed. (author).

  15. Antiproton annihilation physics annihilation physics in the Monte Carlo particle transport code particle transport code SHIELD-HIT12A

    DEFF Research Database (Denmark)

    Taasti, Vicki Trier; Knudsen, Helge; Holzscheiter, Michael;

    2015-01-01

    The Monte Carlo particle transport code SHIELD-HIT12A is designed to simulate therapeutic beams for cancer radiotherapy with fast ions. SHIELD-HIT12A allows creation of antiproton beam kernels for the treatment planning system TRiP98, but first it must be benchmarked against experimental data...

  16. The AFIS experiment: Detecting low energetic antiprotons in a low earth orbit, using an active target detector

    Energy Technology Data Exchange (ETDEWEB)

    Poeschl, Thomas; Gaisbauer, Dominic; Greenwald, Daniel; Hahn, Alexander; Hauptmann, Philipp; Konorov, Igor; Meng, Lingxin; Paul, Stephan [Physics Department E18, Technische Universitaet Muenchen (Germany); Losekamm, Martin [Physics Department E18, Technische Universitaet Muenchen (Germany); Institute of Astronautics, Technische Universitaet Muenchen (Germany); Renker, Dieter [Physics Department E17, Technische Universitaet Muenchen (Germany)

    2014-07-01

    Since the first observation of geomagnetically trapped antiprotons by the PAMELA experiment and the new results on the positron excess by the AMS-02 experiment, the creation and transport of antimatter in the Earth's upper atmosphere attracts more and more attention both at theoretical and experimental side. For this reason the AFIS experiment was initiated to measure the flux of low energetic antiprotons in the South Atlantic Anomaly (SAA). We developed an active target detector made from scintillating fibers connected to silicon photomultipliers which allows to detect antiprotons in the energy interval of about 30 MeV-100 MeV. The stopping curve of incoming antiprotons (Bragg peak) and the signal of outgoing pions created from the annihilation, are used for particle identification as well as triggering. We plan to implement this detector on a 3 unit cubesat satellite in the framework the 'Move2Warp' mission, which is carried out as a student project by the Technische Universitaet Muenchen.

  17. Fusion Rings for Quantum Groups

    DEFF Research Database (Denmark)

    Andersen, Henning Haahr; Stroppel, Catharina

    2012-01-01

    We study the fusion rings of tilting modules for a quantum group at a root of unity modulo the tensor ideal of negligible tilting modules. We identify them in type A with the combinatorial rings from [12] and give a similar description of the sp2n-fusion ring in terms of noncommutative symmetric...... functions. Moreover we give a presentation of all fusion rings in classical types as quotients of polynomial rings. Finally we also compute the fu- sion rings for type G2....

  18. Fusion rings and fusion ideals

    DEFF Research Database (Denmark)

    Andersen, Troels Bak

    This dissertation investigates fusion rings, which are Grothendieck groups of rigid, monoidal, semisimple, abelian categories. Special interest is in rational fusion rings, i.e., fusion rings which admit a finite basis, for as commutative rings they may be presented as quotients of polynomial rings...... by the so-called fusion ideals. The fusion rings of Wess-Zumino-Witten models have been widely studied and are well understood in terms of precise combinatorial descriptions and explicit generating sets of the fusion ideals. They also appear in another, more general, setting via tilting modules for quantum...

  19. Rings from Close Encounters

    Science.gov (United States)

    Kohler, Susanna

    2016-09-01

    Weve recently discovered narrow sets of rings around two minor planets orbiting in our solar system. How did these rings form? A new study shows that they could be a result of close encounters between the minor planets and giants like Jupiter or Neptune.Unexpected Ring SystemsPositions of the centaurs in our solar system (green). Giant planets (red), Jupiter trojans (grey), scattered disk objects (tan) and Kuiper belt objects (blue) are also shown. [WilyD]Centaurs are minor planets in our solar system that orbit between Jupiter and Neptune. These bodies of which there are roughly 44,000 with diameters larger than 1 km have dynamically unstable orbits that cross paths with those of one or more giant planets.Recent occultation observations of two centaurs, 10199 Chariklo and 2060 Chiron, revealed that these bodies both host narrow ring systems. Besides our four giant planets, Chariklo and Chiron are the only other bodies in the solar system known to have rings. But how did these rings form?Scientists have proposed several models, implicating collisions, disruption of a primordial satellite, or dusty outgassing. But a team of scientists led by Ryuki Hyodo (Paris Institute of Earth Physics, Kobe University) has recently proposed an alternative scenario: what if the rings were formed from partial disruption of the centaur itself, after it crossed just a little too close to a giant planet?Tidal Forces from a GiantHyodo and collaborators first used past studies of centaur orbits to estimate that roughly 10% of centaurs experience close encounters (passing within a distance of ~2x the planetary radius) with a giant planet during their million-year lifetime. The team then performed a series of simulations of close encounters between a giant planet and a differentiated centaur a body in which the rocky material has sunk to form a dense silicate core, surrounded by an icy mantle.Some snapshots of simulation outcomes (click for a closer look!) for different initial states of

  20. High-precision comparison of the antiproton-to-proton charge-to-mass ratio.

    Science.gov (United States)

    Ulmer, S; Smorra, C; Mooser, A; Franke, K; Nagahama, H; Schneider, G; Higuchi, T; Van Gorp, S; Blaum, K; Matsuda, Y; Quint, W; Walz, J; Yamazaki, Y

    2015-08-13

    Invariance under the charge, parity, time-reversal (CPT) transformation is one of the fundamental symmetries of the standard model of particle physics. This CPT invariance implies that the fundamental properties of antiparticles and their matter-conjugates are identical, apart from signs. There is a deep link between CPT invariance and Lorentz symmetry--that is, the laws of nature seem to be invariant under the symmetry transformation of spacetime--although it is model dependent. A number of high-precision CPT and Lorentz invariance tests--using a co-magnetometer, a torsion pendulum and a maser, among others--have been performed, but only a few direct high-precision CPT tests that compare the fundamental properties of matter and antimatter are available. Here we report high-precision cyclotron frequency comparisons of a single antiproton and a negatively charged hydrogen ion (H(-)) carried out in a Penning trap system. From 13,000 frequency measurements we compare the charge-to-mass ratio for the antiproton (q/m)p- to that for the proton (q/m)p and obtain (q/m)p-/(q/m)p − 1 =1(69) × 10(-12). The measurements were performed at cyclotron frequencies of 29.6 megahertz, so our result shows that the CPT theorem holds at the atto-electronvolt scale. Our precision of 69 parts per trillion exceeds the energy resolution of previous antiproton-to-proton mass comparisons as well as the respective figure of merit of the standard model extension by a factor of four. In addition, we give a limit on sidereal variations in the measured ratio of <720 parts per trillion. By following the arguments of ref. 11, our result can be interpreted as a stringent test of the weak equivalence principle of general relativity using baryonic antimatter, and it sets a new limit on the gravitational anomaly parameter of |α − 1| < 8.7 × 10(-7). PMID:26268189

  1. e-læring

    DEFF Research Database (Denmark)

    Helms, Niels Henrik

    e-læring kan defineres på ganske mange måder. Ordet e-læring består jo tydeligt nok af to elementer. E + læring ligesom e-handel eller e-banking, og umiddelbart vil de fleste nok sige, at det så handler om læring vha. internettet. I bidraget advokeres for en læringsmæssig frem for normativ tilgang....

  2. The Black Ring is Unstable

    CERN Document Server

    Santos, Jorge E

    2015-01-01

    We study non-axisymmetric linearised gravitational perturbations of the Emparan-Reall black ring using numerical methods. We find an unstable mode whose onset lies within the "fat" branch of the black ring and continues into the "thin" branch. Together with previous results using Penrose inequalities that fat black rings are unstable, this provides numerical evidence that the entire black ring family is unstable.

  3. RINGED ACCRETION DISKS: EQUILIBRIUM CONFIGURATIONS

    Energy Technology Data Exchange (ETDEWEB)

    Pugliese, D.; Stuchlík, Z., E-mail: d.pugliese.physics@gmail.com, E-mail: zdenek.stuchlik@physics.cz [Institute of Physics and Research Centre of Theoretical Physics and Astrophysics, Faculty of Philosophy and Science, Silesian University in Opava, Bezručovo náměstí 13, CZ-74601 Opava (Czech Republic)

    2015-12-15

    We investigate a model of a ringed accretion disk, made up by several rings rotating around a supermassive Kerr black hole attractor. Each toroid of the ringed disk is governed by the general relativity hydrodynamic Boyer condition of equilibrium configurations of rotating perfect fluids. Properties of the tori can then be determined by an appropriately defined effective potential reflecting the background Kerr geometry and the centrifugal effects. The ringed disks could be created in various regimes during the evolution of matter configurations around supermassive black holes. Therefore, both corotating and counterrotating rings have to be considered as being a constituent of the ringed disk. We provide constraints on the model parameters for the existence and stability of various ringed configurations and discuss occurrence of accretion onto the Kerr black hole and possible launching of jets from the ringed disk. We demonstrate that various ringed disks can be characterized by a maximum number of rings. We present also a perturbation analysis based on evolution of the oscillating components of the ringed disk. The dynamics of the unstable phases of the ringed disk evolution seems to be promising in relation to high-energy phenomena demonstrated in active galactic nuclei.

  4. DC-Powered Jumping Ring

    Science.gov (United States)

    Jeffery, Rondo N.; Farhang, Amiri

    2016-01-01

    The classroom jumping ring demonstration is nearly always performed using alternating current (AC), in which the ring jumps or flies off the extended iron core when the switch is closed. The ring jumps higher when cooled with liquid nitrogen (LN2). We have performed experiments using DC to power the solenoid and find similarities and significant…

  5. Fusion Rings for Quantum Groups

    DEFF Research Database (Denmark)

    Andersen, Henning Haahr; Stroppel, Catharina

    2014-01-01

    We study the fusion rings of tilting modules for a quantum group at a root of unity modulo the tensor ideal of negligible tilting modules. We identify them in type A with the combinatorial rings from Korff, C., Stroppel, C.: The sl(ˆn)k-WZNW fusion ring: a combinato-rial construction and a realis...

  6. Torsion units in group rings

    OpenAIRE

    Bist, Vikas

    1992-01-01

    Let U(RG) be the unit group of the group ring RG. In this paper we study group rings RG whose support elements of every torsion unit are torsion, where R is either the ring of integers Z or a field K.

  7. Full two-electron calculations of antiproton collisions with molecular hydrogen

    DEFF Research Database (Denmark)

    Lühr, Armin Christian; Saenz, Alejandro

    2010-01-01

    Total cross sections for single ionization and excitation of molecular hydrogen by antiproton impact are presented over a wide range of impact energies from 1 keV to 6.5 MeV. A nonperturbative time-dependent close-coupling method is applied to fully treat the correlated dynamics of the electrons...... is demonstrated. The present findings provide benchmark results which might be useful for the development of molecular models........ Good agreement is obtained between the present calculations and experimental measurements of single-ionization cross sections at high energies, whereas some discrepancies with the experiment are found around the maximum. The importance of the molecular geometry and a full two-electron description...

  8. Stopping power of antiprotons in H, H2, and He targets

    DEFF Research Database (Denmark)

    Lühr, Armin Christian; Saenz, Alejandro

    2009-01-01

    The stopping power of antiprotons in atomic and molecular hydrogen as well as helium was calculated in an impact-energy range from 1 keV to 6.4 MeV. In the case of H2 and He the targets were described with a single-active electron model centered on the target. The collision process was treated...... of the corrections to the first-order stopping number, the average energy transferred to the target electrons, and the relative importance of the excitation and the ionization process for the energy loss of the projectile was determined. Finally, the stopping powers of the H, H2, and He targets were directly...

  9. Decay of Hot Nuclei at Low Spins Produced by Antiproton-Annihilation in Heavy Nuclei

    CERN Multimedia

    2002-01-01

    % PS208 \\\\ \\\\ The objective of the experiment is to study (i) the thermal excitation energy distribution of antiproton-induced reactions in heavy nuclei and (ii) the decay properties of hot nuclei at low spins via evaporation, multifragmentation and fission as a function of excitation energy. The experimental set-up consists of 4-$\\pi$ detectors: the Berlin Neutron Ball~(BNB) which is a spherical shell of gadolinium-loaded scintillator liquid with an inner and outer diameter of 40 and 160~cm, respectively. This detector counts the number of evaporated neutrons in each reaction. Inside BNB there is a 4-$\\pi$ silicon ball~(BSIB) with a diameter of 20~cm consisting of 162 detectors which measure energy and multiplicity of all emitted charged nuclear particles. The particles are identified via time of flight, energy and pulse shape correlations.

  10. Theoretical motivation for gravitation experiments on ultra-low energy antiprotons and antihydrogen

    Energy Technology Data Exchange (ETDEWEB)

    Nieto, M.M.

    1995-12-31

    It is known that the generally accepted theories of gravity and quantum mechanics are fundamentally incompatible. Thus, when one tries to combine these theories, one must beware of physical pitfalls. Modern theories of quantum gravity are trying to overcome these problems. Any ideas must confront the present agreement with general relativity, but yet be free to wonder about not understood phenomena, such as the dark matter problem. This all has led some {open_quotes}intrepid{close_quotes} theorists to consider a new gravitational regime, that of antimatter. Even more {open_quotes}daring{close_quotes} experimentalists are attempting, or considering attempting, the measurement of the gravitational force on antimatter, including low-energy antiprotons and, perhaps most enticing, antihydrogen.

  11. Hexagonal graphene onion rings.

    Science.gov (United States)

    Yan, Zheng; Liu, Yuanyue; Lin, Jian; Peng, Zhiwei; Wang, Gunuk; Pembroke, Elvira; Zhou, Haiqing; Xiang, Changsheng; Raji, Abdul-Rahman O; Samuel, Errol L G; Yu, Ting; Yakobson, Boris I; Tour, James M

    2013-07-24

    Precise spatial control of materials is the key capability of engineering their optical, electronic, and mechanical properties. However, growth of graphene on Cu was revealed to be seed-induced two-dimensional (2D) growth, limiting the synthesis of complex graphene spatial structures. In this research, we report the growth of onion ring like three-dimensional (3D) graphene structures, which are comprised of concentric one-dimensional hexagonal graphene ribbon rings grown under 2D single-crystal monolayer graphene domains. The ring formation arises from the hydrogenation-induced edge nucleation and 3D growth of a new graphene layer on the edge and under the previous one, as supported by first principles calculations. This work reveals a new graphene-nucleation mechanism and could also offer impetus for the design of new 3D spatial structures of graphene or other 2D layered materials. Additionally, in this research, two special features of this new 3D graphene structure were demonstrated, including nanoribbon fabrication and potential use in lithium storage upon scaling. PMID:23815279

  12. Uranus rings and two moons

    Science.gov (United States)

    1986-01-01

    Voyager 2 has discovered two 'shepherd' satellites associated with the rings of Uranus. The two moons -- designated 1986U7 and 1986U8 -- are seen here on either side of the bright epsilon ring; all nine of the known Uranian rings are visible. The image was taken Jan. 21, 1986, at a distance of 4.1 million kilometers (2.5 million miles) and resolution of about 36 km (22 mi). The image was processed to enhance narrow features. The epsilon ring appears surrounded by a dark halo as a result of this processing; occasional blips seen on the ring are also artifacts. Lying inward from the epsilon ring are the delta, gamma and eta rings; then the beta and alpha rings; and finally the barely visible 4, 5 and 6 rings. The rings have been studied since their discovery in 1977, through observations of how they diminish the light of stars they pass in front of. This image is the first direct observation of all nine rings in reflected sunlight. They range in width from about 100 km (60 mi) at the widest part of the epsilon ring to only a few kilometers for most of the others. The discovery of the two ring moons 1986U7 and 1986U8 is a major advance in our understanding of the structure of the Uranian rings and is in good agreement with theoretical predictions of how these narrow rings are kept from spreading out. Based on likely surface brightness properties, the moons are of roughly 2O- and 3O-km diameter, respectively. The Voyager project is managed for NASA by the Jet Propulsion Laboratory.

  13. An explanation of the elliptic flow difference between proton and anti-proton from the UrQMD model with hadron potentials

    CERN Document Server

    Li, Qingfeng; Wang, Xiaobao; Shen, Caiwan

    2016-01-01

    The time evolution of both proton and anti-proton $v_2$ flows from Au+Au collisions at $\\sqrt{s_{NN}}$=7.7 GeV are examined by using both pure cascade and mean-field potential versions of the UrQMD model. Due to a stronger repulsion at the early stage introduced by the repulsive potentials and hence much less annihilation probabilities, anti-protons are frozen out earlier with smaller $v_2$ values. Therefore, the experimental data of anti-proton $v_2$ as well as the flow difference between proton and anti-proton can be reasonably described with the potential version of UrQMD.

  14. Precision Survey of X-Rays from $\\overline{p}p (\\overline{p}d)$ Atoms Using the Initial LEAR Beam

    CERN Multimedia

    2002-01-01

    The experiment searches for the K and L X-ray series from @*p~(@*d) atoms, then measures their shift and width relative to QED predictions, and investigates their yields as a function of gas density. \\\\ \\\\ The @* are stopped in 1 atmosphere of H2 (D2) gas in a large aluminium flask whose 1 mm wall thickness eliminates externally produced low energy X-rays. The gas is cooled from a remote helium refrigerator and its temperature varied between 30|0K and 300|0K, giving a density range of 10 and large changes in relative line intensities. With 300~mm|2 area and 250~eV resolution FWHM at 5.9~keV, the Si(Li) X-ray detector penetrates the vacuum to come very close to a large beryllium window. Withstanding the large, charged particle flux from @*p annihilations has required special development of the Si(Li) detector. High purity metals are used for flask, window and detector end-housing to reduce background X-ray lines. A NaI ring suppresses the continuum background that comes principally from Compton scattering in t...

  15. Magnetic fields in ring galaxies

    CERN Document Server

    Moss, D; Silchenko, O; Sokoloff, D; Horellou, C; Beck, R

    2016-01-01

    Many galaxies contain magnetic fields supported by galactic dynamo action. However, nothing definitive is known about magnetic fields in ring galaxies. Here we investigate large-scale magnetic fields in a previously unexplored context, namely ring galaxies, and concentrate our efforts on the structures that appear most promising for galactic dynamo action, i.e. outer star-forming rings in visually unbarred galaxies. We use tested methods for modelling $\\alpha-\\Omega$ galactic dynamos, taking into account the available observational information concerning ionized interstellar matter in ring galaxies. Our main result is that dynamo drivers in ring galaxies are strong enough to excite large-scale magnetic fields in the ring galaxies studied. The variety of dynamo driven magnetic configurations in ring galaxies obtained in our modelling is much richer than that found in classical spiral galaxies. In particular, various long-lived transients are possible. An especially interesting case is that of NGC 4513 where th...

  16. Measurement of the Antiprotonic Lyman- and Balmer X-rays of $\\overline{p}H$ and $\\overline{p}D$ Atoms at Very Low Target Pressures

    CERN Multimedia

    2002-01-01

    The aim of this experiment is to measure the energies and intensities of the n @A 1 (Lyman) and n @A 2 (Balmer) tansitions with high accuracy in both @*H and @*D, from which the strong interaction effects of the 1s- and 2p-level can be extracted. These observables may be related to the antiproton-proton and antiproton-neutron scattering length. \\\\ \\\\ Since in these targets collisional Stark effect occurs, we will stop the antiprotons in extreme thin gaseous targets (pressure as low as 10 Torr), where no Stark effect occurs and the 2-1 transition is favoured. In order to use antiprotons with high efficiency despite of the low target density, we will trap antiprotons of a momentum of 100 MeV/c in a magnetic field of cyclotron characteristics. The antiprotons are decelerated by their energy loss in the target gas. The focusing properties of the magnetic field serve to compensate the multiple scattering and we will end up with a concentrated stopping distribution at the centre. Due to the long orbiting time, back...

  17. The Rings Characterized by Minimal Left Ideals

    Institute of Scientific and Technical Information of China (English)

    Jun Chao WEI

    2005-01-01

    We study these rings with every minimal left ideal being a projective, direct summand and a p-injective module, respectively. Some characterizations of these rings are given, and the relations among them are obtained. With these rings, we characterize semisimple rings. Finally, we introduce MC2 rings, and give some characterizations of MC2 rings.

  18. Continuous ring furnaces

    Energy Technology Data Exchange (ETDEWEB)

    De Stefani, G.; Genevois, J.L.; Paolo, P.

    1981-01-06

    A smoke conducting apparatus for use particularly with continuous ring furnaces (e.g., Hoffman furnaces) wherein each furnace chamber is connected to the smoke channel, the latter being a metal pipe inclined slightly from horizontal and provided with one or more traps along the length of its bottom surface, each trap containing a removable receptacle, and heating means being disposed along the bottom of the channel to fluidize tarry deposits of combustion products so that such deposits will flow by gravity into the removable receptacle.

  19. The Structure of Saturn's Rings

    Science.gov (United States)

    Colwell, J. E.; Nicholson, P. D.; Tiscareno, M. S.; Murray, C. D.; French, R. G.; Marouf, E. A.

    Our understanding of the structure of Saturn's rings has evolved steadily since their discovery by Galileo Galilei in 1610. With each advance in observations of the rings over the last four centuries, new structure has been revealed, starting with the recognition that the rings are a disk by Huygens in 1656 through discoveries of the broad organization of the main rings and their constituent gaps and ringlets to Cassini observations that indirectly reveal individual clumps of particles tens of meters in size. The variety of structure is as broad as the range in scales. The main rings have distinct characteristics on a spatial scale of 104 km that suggest dramatically different evolution and perhaps even different origins. On smaller scales, the A and C ring and Cassini Division are punctuated by gaps from tens to hundreds of kilometer across, while the B ring is littered with unexplained variations in optical depth on similar scales. Moons are intimately involved with much of the structure in the rings. The outer edges of the A and B rings are shepherded and sculpted by resonances with the Janus—Epimetheus coorbitals and Mimas, respectively. Density waves at the locations of orbital resonances with nearby and embedded moons make up the majority of large-scale features in the A ring. Moons orbiting within the Encke and Keeler gaps in the A ring create those gaps and produce wakes in the nearby ring. Other gaps and wave-like features await explanation. The largest ring particles, while not massive enough to clear a gap, produce localized propeller-shaped disturbances hundreds of meters long. Particles throughout the A and B rings cluster into strands or self-gravity wakes tens of meters across that are in equilibrium between gravitational accretion and Keplerian shear. In the peaks of strong density waves particles pile together in a cosmic traffic jam that results in kilometer-long strands that may be larger versions of self-gravity wakes. The F ring is a showcase

  20. Viscosity of ring polymer melts

    KAUST Repository

    Pasquino, Rossana

    2013-10-15

    We have measured the linear rheology of critically purified ring polyisoprenes, polystyrenes, and polyethyleneoxides of different molar masses. The ratio of the zero-shear viscosities of linear polymer melts η0,linear to their ring counterparts η0,ring at isofrictional conditions is discussed as a function of the number of entanglements Z. In the unentangled regime η0,linear/η 0,ring is virtually constant, consistent with the earlier data, atomistic simulations, and the theoretical expectation η0,linear/ η0,ring = 2. In the entanglement regime, the Z-dependence of ring viscosity is much weaker than that of linear polymers, in qualitative agreement with predictions from scaling theory and simulations. The power-law extracted from the available experimental data in the rather limited range 1 < Z < 20, η0,linear/η0,ring ∼ Z 1.2±0.3, is weaker than the scaling prediction (η0,linear/η0,ring ∼ Z 1.6±0.3) and the simulations (η0,linear/ η0,ring ∼ Z2.0±0.3). Nevertheless, the present collection of state-of-the-art experimental data unambiguously demonstrates that rings exhibit a universal trend clearly departing from that of their linear counterparts, and hence it represents a major step toward resolving a 30-year-old problem. © 2013 American Chemical Society.

  1. Liquid helium-free cryostat and hermetically sealed cryogenic microwave cavity for hyperfine spectroscopy of antiprotonic helium.

    Science.gov (United States)

    Massiczek, O; Friedreich, S; Juhász, B; Widmann, E; Zmeskal, J

    2011-12-11

    The design and properties of a new cryogenic set-up for laser-microwave-laser hyperfine structure spectroscopy of antiprotonic helium - an experiment performed at the CERN-Antiproton Decelerator (AD), Geneva, Switzerland - are described. Similar experiments for (4)He have been performed at the AD for several years. Due to the usage of a liquid helium operated cryostat and therefore necessary refilling of coolants, a loss of up to 10% beamtime occurred. The decision was made to change the cooling system to a closed-circuit cryocooler. New hermetically sealed target cells with minimised (3)He gas volume and different dimensions of the microwave resonator for measuring the (3)He transitions were needed. A new set-up has been designed and tested at Stefan Meyer Institute in Vienna before being used for the 2009 and 2010 beamtimes at the AD.

  2. Liquid helium-free cryostat and hermetically sealed cryogenic microwave cavity for hyperfine spectroscopy of antiprotonic helium

    Energy Technology Data Exchange (ETDEWEB)

    Massiczek, O., E-mail: oswald.massiczek@cern.ch [Stefan Meyer Institute for Subatomic Physics, Austrian Academy of Sciences, Boltzmanngasse 3, 1090 Vienna (Austria); Friedreich, S.; Juhasz, B.; Widmann, E.; Zmeskal, J. [Stefan Meyer Institute for Subatomic Physics, Austrian Academy of Sciences, Boltzmanngasse 3, 1090 Vienna (Austria)

    2011-12-11

    The design and properties of a new cryogenic set-up for laser-microwave-laser hyperfine structure spectroscopy of antiprotonic helium - an experiment performed at the CERN-Antiproton Decelerator (AD), Geneva, Switzerland - are described. Similar experiments for {sup 4}He have been performed at the AD for several years. Due to the usage of a liquid helium operated cryostat and therefore necessary refilling of coolants, a loss of up to 10% beamtime occurred. The decision was made to change the cooling system to a closed-circuit cryocooler. New hermetically sealed target cells with minimised {sup 3}He gas volume and different dimensions of the microwave resonator for measuring the {sup 3}He transitions were needed. A new set-up has been designed and tested at Stefan Meyer Institute in Vienna before being used for the 2009 and 2010 beamtimes at the AD.

  3. Scaling properties of proton and antiproton production in sqrt[s(NN)]=200 GeV Au+Au collisions.

    Science.gov (United States)

    Adler, S S; Afanasiev, S; Aidala, C; Ajitanand, N N; Akiba, Y; Alexander, J; Amirikas, R; Aphecetche, L; Aronson, S H; Averbeck, R; Awes, T C; Azmoun, R; Babintsev, V; Baldisseri, A; Barish, K N; Barnes, P D; Bassalleck, B; Bathe, S; Batsouli, S; Baublis, V; Bazilevsky, A; Belikov, S; Berdnikov, Y; Bhagavatula, S; Boissevain, J G; Borel, H; Borenstein, S; Brooks, M L; Brown, D S; Bruner, N; Bucher, D; Buesching, H; Bumazhnov, V; Bunce, G; Burward-Hoy, J M; Butsyk, S; Camard, X; Chai, J-S; Chand, P; Chang, W C; Chernichenko, S; Chi, C Y; Chiba, J; Chiu, M; Choi, I J; Choi, J; Choudhury, R K; Chujo, T; Cianciolo, V; Cobigo, Y; Cole, B A; Constantin, P; d'Enterria, D G; David, G; Delagrange, H; Denisov, A; Deshpande, A; Desmond, E J; Dietzsch, O; Drapier, O; Drees, A; du Rietz, R; Durum, A; Dutta, D; Efremenko, Y V; El Chenawi, K; Enokizono, A; En'yo, H; Esumi, S; Ewell, L; Fields, D E; Fleuret, F; Fokin, S L; Fox, B D; Fraenkel, Z; Frantz, J E; Franz, A; Frawley, A D; Fung, S-Y; Garpman, S; Ghosh, T K; Glenn, A; Gogiberidze, G; Gonin, M; Gosset, J; Goto, Y; Granier de Cassagnac, R; Grau, N; Greene, S V; Grosse Perdekamp, G; Guryn, W; Gustafsson, H-A; Hachiya, T; Haggerty, J S; Hamagaki, H; Hansen, A G; Hartouni, E P; Harvey, M; Hayano, R; He, X; Heffner, M; Hemmick, T K; Heuser, J M; Hibino, M; Hill, J C; Holzmann, W; Homma, K; Hong, B; Hoover, A; Ichihara, T; Ikonnikov, V V; Imai, K; Isenhower, L D; Ishihara, M; Issah, M; Isupov, A; Jacak, B V; Jang, W Y; Jeong, Y; Jia, J; Jinnouchi, O; Johnson, B M; Johnson, S C; Joo, K S; Jouan, D; Kametani, S; Kamihara, N; Kang, J H; Kapoor, S S; Katou, K; Kelly, S; Khachaturov, B; Khanzadeev, A; Kikuchi, J; Kim, D H; Kim, D J; Kim, D W; Kim, E; Kim, G-B; Kim, H J; Kistenev, E; Kiyomichi, A; Kiyoyama, K; Klein-Boesing, C; Kobayashi, H; Kochenda, L; Kochetkov, V; Koehler, D; Kohama, T; Kopytine, M; Kotchetkov, D; Kozlov, A; Kroon, P J; Kuberg, C H; Kurita, K; Kuroki, Y; Kweon, M J; Kwon, Y; Kyle, G S; Lacey, R; Ladygin, V; Lajoie, J G; Lebedev, A; Leckey, S; Lee, D M; Lee, S; Leitch, M J; Li, X H; Lim, H; Litvinenko, A; Liu, M X; Liu, Y; Maguire, C F; Makdisi, Y I; Malakhov, A; Manko, V I; Mao, Y; Martinez, G; Marx, M D; Masui, H; Matathias, F; Matsumoto, T; McGaughey, P L; Melnikov, E; Messer, F; Miake, Y; Milan, J; Miller, T E; Milov, A; Mioduszewski, S; Mischke, R E; Mishra, G C; Mitchell, J T; Mohanty, A K; Morrison, D P; Moss, J M; Mühlbacher, F; Mukhopadhyay, D; Muniruzzaman, M; Murata, J; Nagamiya, S; Nagle, J L; Nakamura, T; Nandi, B K; Nara, M; Newby, J; Nilsson, P; Nyanin, A S; Nystrand, J; O'Brien, E; Ogilvie, C A; Ohnishi, H; Ojha, I D; Okada, K; Ono, M; Onuchin, V; Oskarsson, A; Otterlund, I; Oyama, K; Ozawa, K; Pal, D; Palounek, A P T; Pantuev, V S; Papavassiliou, V; Park, J; Parmar, A; Pate, S F; Peitzmann, T; Peng, J-C; Peresedov, V; Pinkenburg, C; Pisani, R P; Plasil, F; Purschke, M L; Purwar, A; Rak, J; Ravinovich, I; Read, K F; Reuter, M; Reygers, K; Riabov, V; Riabov, Y; Roche, G; Romana, A; Rosati, M; Rosnet, P; Ryu, S S; Sadler, M E; Saito, N; Sakaguchi, T; Sakai, M; Sakai, S; Samsonov, V; Sanfratello, L; Santo, R; Sato, H D; Sato, S; Sawada, S; Schutz, Y; Semenov, V; Seto, R; Shaw, M R; Shea, T K; Shibata, T-A; Shigaki, K; Shiina, T; Silva, C L; Silvermyr, D; Sim, K S; Singh, C P; Singh, V; Sivertz, M; Soldatov, A; Soltz, R A; Sondheim, W E; Sorensen, S P; Sourikova, I V; Staley, F; Stankus, P W; Stenlund, E; Stepanov, M; Ster, A; Stoll, S P; Sugitate, T; Sullivan, J P; Takagui, E M; Taketani, A; Tamai, M; Tanaka, K H; Tanaka, Y; Tanida, K; Tannenbaum, M J; Tarján, P; Tepe, J D; Thomas, T L; Tojo, J; Torii, H; Towell, R S; Tserruya, I; Tsuruoka, H; Tuli, S K; Tydesjö, H; Tyurin, N; Van Hecke, H W; Velkovska, J; Velkovsky, M; Villatte, L; Vinogradov, A A; Volkov, M A; Vznuzdaev, E; Wang, X R; Watanabe, Y; White, S N; Wohn, F K; Woody, C L; Xie, W; Yang, Y; Yanovich, A; Yokkaichi, S; Young, G R; Yushmanov, I E; Zajc, W A; Zhang, C; Zhou, S; Zolin, L

    2003-10-24

    We report on the yield of protons and antiprotons, as a function of centrality and transverse momentum, in Au+Au collisions at sqrt[s(NN)]=200 GeV measured at midrapidity by the PHENIX experiment at the BNL Relativistic Heavy Ion Collider. In central collisions at intermediate transverse momenta (1.5antiprotons. They show a centrality-scaling behavior different from that of pions. The pmacr;/pi and p/pi ratios are enhanced compared to peripheral Au+Au, p+p, and e(+)e(-) collisions. This enhancement is limited to p(T)<5 GeV/c as deduced from the ratio of charged hadrons to pi(0) measured in the range 1.5

  4. Beam-spin asymmetry of pion, kaon, proton and antiproton production in semi-inclusive deep-inelastic scattering

    International Nuclear Information System (INIS)

    Beam-spin asymmetries in the azimuthal distribution of pions, kaons, protons and antiprotons in semi-inclusive deep inelastic scattering (SIDIS) extracted from 2000-2007 HERMES data are presented. The asymmetries were measured in the kinematic region Q2>1 GeV2, W2 > 10 GeV2, 0.1 antiprotons are shown. Assuming that the SIDIS cross section factorizes to distribution (DF) and fragmentation (FF) functions that dependent on transverse quark momentum (TMD functions), one can obtain novel information about the spin-orbit correlations inside the nucleon and orbital angular momentum of quarks.

  5. Shock accelerated vortex ring

    CERN Document Server

    Haehn, N; Oakley, J; Anderson, M; Rothamer, D; Bonazza, R

    2009-01-01

    The interaction of a shock wave with a spherical density inhomogeneity leads to the development of a vortex ring through the impulsive deposition of baroclinic vorticity. The present fluid dynamics videos display this phenomenon and were experimentally investigated at the Wisconsin Shock Tube Laboratory's (WiSTL) 9.2 m, downward firing shock tube. The tube has a square internal cross-section (0.25 m x 0.25 m) with multiple fused silica windows for optical access. The spherical soap bubble is generated by means of a pneumatically retracted injector and released into free-fall 200 ms prior to initial shock acceleration. The downward moving, M = 2.07 shock wave impulsively accelerates the bubble and reflects off the tube end wall. The reflected shock wave re-accelerates the bubble (reshock), which has now developed into a vortex ring, depositing additional vorticity. In the absence of any flow disturbances, the flow behind the reflected shock wave is stationary. As a result, any observed motion of the vortex rin...

  6. Ring Image Analyzer

    Science.gov (United States)

    Strekalov, Dmitry V.

    2012-01-01

    Ring Image Analyzer software analyzes images to recognize elliptical patterns. It determines the ellipse parameters (axes ratio, centroid coordinate, tilt angle). The program attempts to recognize elliptical fringes (e.g., Newton Rings) on a photograph and determine their centroid position, the short-to-long-axis ratio, and the angle of rotation of the long axis relative to the horizontal direction on the photograph. These capabilities are important in interferometric imaging and control of surfaces. In particular, this program has been developed and applied for determining the rim shape of precision-machined optical whispering gallery mode resonators. The program relies on a unique image recognition algorithm aimed at recognizing elliptical shapes, but can be easily adapted to other geometric shapes. It is robust against non-elliptical details of the image and against noise. Interferometric analysis of precision-machined surfaces remains an important technological instrument in hardware development and quality analysis. This software automates and increases the accuracy of this technique. The software has been developed for the needs of an R&TD-funded project and has become an important asset for the future research proposal to NASA as well as other agencies.

  7. Buoyant Norbury's vortex rings

    Science.gov (United States)

    Blyth, Mark; Rodriguez-Rodriguez, Javier; Salman, Hayder

    2014-11-01

    Norbury's vortices are a one-parameter family of axisymmetric vortex rings that are exact solutions to the Euler equations. Due to their relative simplicity, they are extensively used to model the behavior of real vortex rings found in experiments and in Nature. In this work, we extend the original formulation of the problem to include buoyancy effects for the case where the fluid that lies within the vortex has a different density to that of the ambient. In this modified formulation, buoyancy effects enter the problem through the baroclinic term of the vorticity equation. This permits an efficient numerical solution of the governing equation of motion in terms of a vortex contour method that tracks the evolution of the boundary of the vortex. Finally, we compare our numerical results with the theoretical analysis of the short-time evolution of a buoyant vortex. Funded by the Spanish Ministry of Economy and Competitiveness through grant DPI2011-28356-C03-02 and by the London Mathematical Society.

  8. Cosmic ray propagation in a diffusion model: a new estimation of the diffusion parameters and of the secondary antiprotons flux

    International Nuclear Information System (INIS)

    Dark matter is present at numerous scale of the universe (galaxy, cluster of galaxies, universe in the whole). This matter plays an important role in cosmology and can not be totally explained by conventional physic. From a particle physic point of view, there exists an extension of the standard model - supersymmetry - which predicts under certain conditions the existence of new stable and massive particles, the latter interacting weakly with ordinary matter. Apart from direct detection in accelerators, various indirect astrophysical detection are possible. This thesis focuses on one particular signature: disintegration of these particles could give antiprotons which should be measurable in cosmic rays. The present study evaluates the background corresponding to this signal i. e. antiprotons produced in the interactions between these cosmic rays and interstellar matter. In particular, uncertainties of this background being correlated to the uncertainties of the diffusion parameter, major part of this thesis is devoted to nuclei propagation. The first third of the thesis introduces propagation of cosmic rays in our galaxy, emphasizing the nuclear reaction responsibles of the nuclei fragmentation. In the second third, different models are reviewed, and in particular links between the leaky box model and the diffusion model are recalled (re-acceleration and convection are also discussed). This leads to a qualitative discussion about information that one can infer from propagation of these nuclei. In the last third, we finally present detailed solutions of the bidimensional diffusion model, along with constrains obtained on the propagation parameters. The latter is applied on the antiprotons background signal and it concludes the work done in this thesis. The propagation code for nuclei and antiprotons used here has proven its ability in data analysis. It would probably be of interest for the analysis of the cosmic ray data which will be taken by the AMS experiment on

  9. n-X-Coherent Rings

    CERN Document Server

    Bennis, Driss

    2010-01-01

    This paper unifies several generalizations of coherent rings in one notion. Namely, we introduce $n$-$\\mathscr{X}$-coherent rings, where $\\mathscr{X}$ is a class of modules and $n$ is a positive integer, as those rings for which the subclass $\\mathscr{X}_n$ of $n$-presented modules of $\\mathscr{X}$ is not empty, and every module in $\\mathscr{X}_n$ is $n+1$-presented. Then, for each particular class $\\mathscr{X}$ of modules, we find correspondent relative coherent rings. Our main aim is to show that the well-known Chase's, Cheatham and Stone's, Enochs', and Stenstrom's characterizations of coherent rings hold true for any $n$-$\\mathscr{X}$-coherent rings.

  10. On thickness of Saturn rings

    International Nuclear Information System (INIS)

    Electronographic plates of Saturn were taken during the transit of the Earth through the ring plane. Observing conditions were more favorable than those prevailing in 1966. Thanks to the quality of the detectors and the telescopes, it has been possible to make a more precise photometric determination of the brightness of the ring seen edge on and to measure the brightness variation with respect to the distance to the center of the planet. Extrapolating to the case where the elevation of the Earth above the ring plane is strictly zero, we deduce an apparent photometric ring thickness equal to 1.5+-0.3 km. For an homogeneous layer of small particles colliding inelastically, theory predicts a thickness of the order of a few particles radii, i.e. a few tens of meters. The observed brightness could be explained by the E ring, the brightness of large chunks, condensations and warping of the ring

  11. Burnside Rings of Fusion Systems

    DEFF Research Database (Denmark)

    Reeh, Sune Precht

    , and we produce a basis for the Burnside ring that shares properties with the transitive sets for a finite group. We construct a transfer map from the p-local Burnside ring of the underlying p-group S to the p-local Burnside ring of F. Using such transfer maps, we give a new explicit construction...... of Burnside rings given by multiplication with the characteristic idempotent, and we show that this map is the transfer map previously constructed. Applying these results, we show that for every saturated fusion system the ring generated by all (non-idempotent) characteristic elements in the p-local double...... of the characteristic idempotent of F { the unique idempotent in the p-local double Burnside ring of S satisfying properties of Linckelmann and Webb. We describe this idempotent both in terms of fixed points and as a linear combination of transitive bisets. Additionally, using fixed points we determine the map...

  12. Precision Measurement of Low-Energy Antiprotons with GAPS for Dark Matter and Primordial Black Hole Physics

    CERN Document Server

    Aramaki, T; von Doetinchem, P; Fuke, H; Hailey, C J; Mognet, S A I; Ong, R A; Perez, K M; Zweerink, J

    2014-01-01

    The general antiparticle spectrometer (GAPS) experiment is an indirect dark matter search focusing on antiparticles produced by WIMP annihilation and decay in the Galactic halo. In addition to the very powerful search channel provided by antideuterons, GAPS has a strong capability to measure low-energy antiprotons (0.07 $\\le$ E $\\le$ 0.25 GeV) as dark matter signatures. This is an especially effective means for probing light dark matter, whose existence has been hinted at in the direct dark matter searches, including the recent result from the CDMS-II experiment. While severely constrained by LUX and other direct dark matter searches, light dark matter candidates are still viable in an isospin- violating dark matter scenario and halo-independent analysis. Along with the excellent antideuteron sensitivity, GAPS will be able to detect an order of magnitude more low-energy antiprotons, compared to BESS and PAMELA, providing a precision measurement of low-energy antiproton flux and a unique channel for probing li...

  13. Filtration on a Ring Make a Quasi Valuation or Valuation Ring

    OpenAIRE

    Mohammad Hassan Anjom SHoa

    2014-01-01

    In this paper we show that if R is a filtered ring then we can define a quasi valuation ring. And there exists a valuation ring if R is some kind of filtered ring. Then we prove some properties and relations between filtered ring and quasi valuation ring and valuation ring.

  14. Filtration on a Ring Make a Quasi Valuation or Valuation Ring

    OpenAIRE

    SHoa, Mohammad Hassan Anjom

    2014-01-01

    In this paper we show that if R is a filtered ring then we can define a quasi valuation ring. And there exists a valuation ring if R is some kind of filtered ring. Then we prove some properties and relations between filtered ring and quasi valuation ring and valuation ring

  15. Platinum-catalysed intravaginal rings

    OpenAIRE

    Malcolm, Karl; Woolfson, David; Romano, Joseph

    2012-01-01

    The present invention provides improved intravaginal drug delivery devices, i.e., intravaginal rings, useful for the prophylactic administration of an antimicrobial compound, e.g., Dapivirine, to a human. The intravaginal rings of the invention address previous stability issues by utilizing a platinum catalyst (e.g., in the form of a platinum-siloxane complex) for the cross-linking reaction. The vaginal rings surprisingly achieve relatively high and steady release rates in vivo with a matrix ...

  16. On g-Semisymmetric Rings

    OpenAIRE

    Farahat S. Aly; Al Mestady, Mohammed O.

    2012-01-01

    We introduce right (left) g-semisymmetric ring as a new concept to generalize the well-known concept: symmetric ring. Examples are given to show that these classes of rings are distinct. They coincide under some conditions. It is shown that R is bounded right g-semisymmetric with boundary 1 from right if and only if R is symmetric, whenever R is regular. It is shown that a ring R is strongly regular if and only if R is regular and bounded right g-semisymmetric with boundary 1 from right. For ...

  17. Topics in commutative ring theory

    CERN Document Server

    Watkins, John J

    2009-01-01

    Topics in Commutative Ring Theory is a textbook for advanced undergraduate students as well as graduate students and mathematicians seeking an accessible introduction to this fascinating area of abstract algebra. Commutative ring theory arose more than a century ago to address questions in geometry and number theory. A commutative ring is a set-such as the integers, complex numbers, or polynomials with real coefficients--with two operations, addition and multiplication. Starting from this simple definition, John Watkins guides readers from basic concepts to Noetherian rings-one of

  18. Why Are Ring Galaxies Interesting?

    CERN Document Server

    Higdon, James L

    2010-01-01

    Compared with ordinary spirals, the ISM in ring galaxies experiences markedly different physical conditions and evolution. As a result, ring galaxies provide interesting perspectives on the triggering/quenching of large scale star formation and the destructive effects of massive stars on molecular cloud complexes. We use high resolution radio, sub-millimeter, infrared, and optical data to investigate the role of gravitational stability in star formation regulation, factors influencing the ISM's molecular fraction, and evidence of peculiar star formation laws and efficiencies in two highly evolved ring galaxies: Cartwheel and the Lindsay-Shapley ring.

  19. On Weakly P.P. Rings

    Institute of Scientific and Technical Information of China (English)

    Xiang Yue-ming; Ouyang Lun-qun; Wang Shu-gui

    2015-01-01

    We introduce, in this paper, the right weakly p.p. rings as the generaliza-tion of right p.p. rings. It is shown that many properties of the right p.p. rings can be extended onto the right weakly p.p. rings. Relative examples are constructed. As applications, we also characterize the regular rings and the semisimple rings in terms of the right weakly p.p. rings.

  20. The eRHIC Ring-Ring Collider Design

    CERN Document Server

    Wang, Fuhua; Beebe-Wang, Joanne; Deshpande, Abhay A; Farkhondeh, Manouchehr; Franklin, Wilbur; Graves, William; Litvinenko, Vladimir N; MacKay, William W; Milner, Richard; Montag, Christoph; Ozaki, Satoshi; Parker, Brett; Peggs, Steve; Ptitsyn, Vadim; Roser, Thomas; Tepikian, Steven; Trbojevic, Dejan; Tschalär, C; Wang, Dong; Zolfaghari, Abbasali; Zwart, Townsend; van der Laan, Jan

    2005-01-01

    The eRHIC ring-ring collider is the main design option of the future lepton-ion collider at Brookhaven National Laboratory. We report the revisions of the ring-ring collider design features to the baseline design presented in the eRHIC Zeroth Design Report (ZDR). These revisions have been made during the past year. They include changes of the interaction region which are required from the modifications in the design of the main detector. They also include changes in the lepton storage ring for high current operations as a result of better understandings of beam-beam interaction effects. The updated collider luminosity and beam parameters also take into account a more accurate picture of current and future operational aspects of RHIC.