1,579 research outputs found
Faserhodoskope im COMPASS-Experiment zum Nachweis von Teilchenspuren innerhalb des Primärstrahls
No full textFür das COMPASS-Experiment am CERN wurden Hodoskope aus szintillierenden Fasern entwickelt, getestet und in das Experiment integriert. Die Spurrekonstruktion im oder in unmittelbarer Nähe des Primärstrahls stellt hohe Anforderungen in Bezug auf Ratenfestigkeit, Zeitauflösung, Nachweiseffizienz und Strahlenhärte aller Detektorkomponenten. Vorstudien zur Eignung von szintillierenden Fasern und Lichtleitern in Verbindung mit Vielkanal-Photomultipliern führten zur Fertigung eines Prototyps, der bei nominalen Bedingungen intensiv getestet wurde. Mit den hieraus gewonnen Erfahrungen wurden insgesamt vier Faserhodoskope realisiert und im Rahmen des COMPASS-Experiments betrieben. Hierbei wurde eine intrinsische Detektoreffizienz von nahezu 100% erreicht. Mit einer Zeitauflösung von etwa 450 ps bei gleichzeitig geringen Treffermultiplizitäten ist eine eindeutige Rekonstruktion von Teilchenspuren auch bei Strahlraten von bis zu 100 MHz möglich. Im Dauerbetrieb über 250 Tage während zweier Strahlzeiten zeigten die Detektoren eine hohe Zuverlässigkeit und Langzeitstabilität
Jens Christian Grøndahl
No full textThis is a short presentation of the main works of the Danish author Jens Christian Grøndahl
Jens August Schade
No full textShort presentation of Danish author Jens August Schade and his main work
Interview with Jens Zimmermann: Author of ‘Hermeneutics: A Very Short Introduction’
No full textDr. Jens Zimmermann is a German-Canadian philosopher and J.I. Packer Professor of Theology at Regent College. As the author of Hermeneutics: A Very Short Introduction, he held a lecture titled “Gadamer, Ricoeur and the Future of Philosophical Hermeneutics” at SFU. Hosted by the Department of World Languages and Literatures, the lecture focused on how we can use the art of hermeneutics to interpret literature and our identities of being human
Messung transversaler Spineffekte mittels zwei Hadronen Korrelation am COMPASS–Experiment
No full textDie Quark–Struktur des Nukleons lässt sich bei Vernachlässigung intrinsischer Quarktransversalimpulse vollständig durch drei Quark Verteilungsfunktionen beschreiben. Diese sind die unpolarisierte Quark Verteilungsfunktion q(x), die Helizitäts– Verteilungsfunktion Δq(x) und die transversale Quarkspin Verteilungsfunktion ΔTq(x). Diese letztgenannte Funktion, genannt Transversity Funktion, ist chiral ungerade und kann deshalb nur in Kombination mit einer anderen chiral ungeraden Funktion gemessen werden. Eine Zugangsmöglichkeit zur Transversity Funktion ΔTq(x) ist die semi–inklusive zwei Hadronenproduktion in tief inelastischer Streuung an einem transversal polarisierten Target. Dabei misst man die Faltung der chiral ungeraden zwei Hadronen Interferenz Fragmentationsfunktion (IFF) H1(z,Mh2) und der chiral ungeraden Transversity Funktion. Die IFF H1(z,Mh2) ist der spinabhängige Teil einer Fragmentationsfunktion, die die Fragmentation eines transversal polarisierten Quarks in zwei unpolarisierte Hadronen beschreibt. Die Produktion der zwei Hadronen erfolgt in einer Interferenz zwischen verschiedenen Wellenzuständen der Hadronenpaare. Man misst azimuthale Asymmetrien in den erzeugten Hadronenpaaren. Die Messungen, die in dieser Arbeit beschrieben werden, wurden am COMPASS Experiment am CERN in den Jahren 2002–2004 durchgeführt, welches ein Feststoff Target Experiment am SPS Beschleuniger ist. Nach einer Einführung werden in Kapitel 2 die zugrundeliegenden theoretischen Konzepte zur Messung der ”Transversity” Funktion vorgestellt. In Kapitel 3 wird das COMPASS Experiment beschrieben. Schließlich werden in Kapitel 4 die Auswertemethoden besprochen, die Ergebnisse der azimuthalen Asymmetrien gezeigt und mit theoretischen Vorhersagen verglichen.</p
Investigation and Optimization of Transverse Non-Linear Beam Dynamics in the High-Energy Storage Ring HESR
No full textThe High-Energy Storage Ring HESR is part of the upcoming Facility for Antiproton and Ion Research FAIR which is planned as a major extension to the present facility of the Helmholtzzentrum für Schwerionenforschung (GSI) in Darmstadt. The HESR will provide antiprotons in the momentum range from 1.5 to 15 GeV/c for the internal target experiment PANDA. Long beam life time and a minimum of beam loss is inevitable due to the demanding requirements of PANDA in terms of beam quality, luminosity and limited production rate of antiprotons. Therefore, an effective closed orbit correction and a sufficiently large dynamic aperture of the HESR are crucial. The expected misalignments of beam guiding magnets have been estimated and used to simulate the closed orbit in the HESR. A closed orbit correction scheme has been developed for different ion-optical settings of the HESR and numerical simulations have been performed to validate the closed orbit correction scheme. The proposed closed orbit correction method which utilizes the orbit response matrix has been benchmarked at the Cooler Synchrotron COSY of the Forschungszentrum Jülich. A chromaticity correction scheme for the HESR has been developed using sextupole magnets in order to reduce tune spread and thus avoid emittance growth caused by betatron resonances. The chromaticity correction scheme has been optimized utilizing dynamic aperture calculations. The estimated field errors of the HESR dipole and quadrupole magnets have been taken into account and investigations concerning their optimization have been carried out. The ion-optical settings of the HESR have been improved using, besides dynamic aperture calculations, the technique of frequency map analysis. The related diffusion coefficient was also used to predict long-term stability based on short-term particle tracking. With a reasonable reduction of the quadrupole magnets field errors and a different choice of tunes, the dynamic aperture was improved by roughly a factor two. The inner area of the dynamic aperture where the particle motion is stable on a long-term scale increased and includes more than 3 beam size and the specified maximum closed orbit deviations
Transverse Λ polarization from a transversely polarized proton target at the COMPASS experiment
No full textThe measurement of the transverse spin quark distribution functions ΔTq(xBj) is an important part of the physics program of the COMPASS experiment at CERN. These transversity distributions, being chiral-odd objects, are not accessible in inclusive deep-inelastic scattering (DIS), requiring the presence of another chiral-odd object. At COMPASS, ΔTq(xBj) can be measured in semi-inclusive deep-inelastic scattering (SIDIS), where a promising channel is the spin transfer to the Λ hyperons. Here, the fragmentation functions ΔTDΛq(z) provide the other chiral-odd object. In this thesis, the semi-inclusive Λ production mechanism is introduced to show the connection between a potentially measured Λ polarization PΛ and the ΔTq(xBj) functions. An expression for the angular distribution of the weak decay Λ → pπ- is used which allows to extract PΛ independent of acceptance effects of the spectrometer. In 2007 a 160 GeV/c longitudinally polarized muon beam and a transversely polarized NH3 target were employed in the COMPASS experiment. Based on the full 2007 statistics with transverse target spin configuration, the Λ and anti-Λ polarizations are analyzed as a function of xBj and z. The Λ and anti-Λ hyperons are unpolarized within their statistical errors and show no dependence on either xBj or z.<br /
Measurement of Transverse Momentum Dependent Asymmetries with COMPASS Experiment at CERN
No full textThe COMPASS experiment, which started running at the European Council for Nuclear Research, CERN, in Geneva in 2001, is currently investigating in a wide ranging programme the spin structure of the nucleon through deep-inelastic scatter- ing (DIS). The experiment uses a polarized muon beam and a polarized deuterium target, which together allow access to all terms of the polarized DIS cross-section. Two of the most important functions which COMPASS is designed to ful¯l are a precision measurement of the gluon polarization ¢G and the investigation of the transverse spin e®ects, specially extracting the transverse polarized quark distribu- tion functions ¢T q. In Semi-Inclusive DIS of polarized leptons on a transversely polarized target, eight azimuthal modulations appear in the cross-section. Within the QCD parton model, four azimuthal asymmetries can be interpreted at leading order, two of them being the Collins and Sivers asymmetries. The other two leading twist asymmetries are related to di®erent transverse momentum dependent quark distribution functions. There are four additional asymmetries which can be inter- preted as twist-three contributions. This thesis describes the analysis with the data taken with transverse spin con¯guration during the COMPASS beam-time 2002 - 2004, resulting in the extraction of the eight Transverse Momentum Dependent (TMD) asymmetries
Advanced pharmaceutical solids / Jens T. Carstensen.
No full textIncludes bibliographical references and index.viii, 518 pages :Explores the principles, instrumentation, processes, and programs of pharmaceutical solid science as well as fresh aspects on one-component systems, micromeritics, polymorphism, solid-state stability, cohesion, powder flow, blending, single-unit sustained release, and tablet coatin
Reputation and Organizational Politics: Inside the EU Commission
No full textThe replication data contains the data and do-file necessary to replicate the results presented in "Reputation and Organizational Politics: Inside the European Commission" by Jens Blom-Hansen and Daniel Finke, forthcoming in the Journal of Politics. Corresponding Author: Jens Blom-Hansen, [email protected].
The raw data is a report of the activities recorded in the CIS-net data base operated by the European Commission in 2015 and 2016 (cisnet20152016_jop.dta). The CIS-net data base is further described in the article
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