866 research outputs found
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Silicon drift chamber studies for the RHIC STAR experiment
No full textThe two-hit resolution of a silicon drift chamber is measured using a pulsed Nd:Yag laser and a time digitizer readout. The data is analyzed by forming the covariance matrix in time samples, and transforming to a matrix in amplitude and time variation of each of the two hits. The resolution of the two-hit separation is found to be better than 25 microns with a drift field of 530 V/cm and a separation of more than 500 microns, with the resolution increasing to 50 microns as the separation nears 500 microns. Results are also presented for multiply ionizing tracks, showing a great improvement over single minimum ionizing. 8 refs
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PION INTERFEROMETRY STUDIES OF REIATIVISTIC HEAVY-ION COLLISIONS USING THE INTRANUCLEAR CASCADE MODEL
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Silicon drift-chamber studies for possible use at RHIC
No full textIt is proposed to continue the program now underway at the University of Pittsburgh to study the feasibility of using silicon drift-chambers as particle tracking devices at RHIC. We are currently testing a UA6-type detector obtained from BNL and plan to also study a new device that will become available this year: a cylindrical geometry detector designed for NA45 (CERN). In addition we propose to fabricate and study a detector to be used in vertex determination for the RHIC OASIS experiment. The two-year budget for this proposal is $246.962. 5 refs., 12 figs
correlations in 7 TeV pp collisions from the ALICE experiment at the LHC
No full textIdentical neutral kaon pair correlations are measured in 7 TeV pp collisions in the ALICE experiment. K0s-K0s correlation functions are formed in 3 multiplicity X 4 kT bins. The femtoscopic kaon source parameters Rinv and lambda are extracted from these correlation functions by fitting a (femtoscopy) X (PYTHIA) model to them, PYTHIA accounting for the non-flat baseline found in pp collisions. Source parameters are obtained from a fit which includes quantum statistics and final-state interactions of the a0/f0 resonance. K0s-K0s correlations show a systematic increase in Rinv for increasing multiplicity bin and decreasing Rinv for increasing kT bin as seen in pi-pi correlations in the pp system, as well as seen in heavy-ion collisions. Also, K0s-K0s correlations are observed to smoothly extend this pi-pi Rinv behavior for the pp system up to about three times higher kT than the kT range measured in pi-pi correlations.Identical neutral kaon pair correlations are measured in 7 TeV pp collisions in the ALICE experiment. K0s-K0s correlation functions are formed in 3 multiplicity X 4 kT bins. The femtoscopic kaon source parameters Rinv and lambda are extracted from these correlation functions by fitting a (femtoscopy) X (PYTHIA) model to them, PYTHIA accounting for the non-flat baseline found in pp collisions. Source parameters are obtained from a fit which includes quantum statistics and final-state interactions of the a0/f0 resonance. K0s-K0s correlations show a systematic increase in Rinv for increasing multiplicity bin and decreasing Rinv for increasing kT bin as seen in pi-pi correlations in the pp system, as well as seen in heavy-ion collisions. Also, K0s-K0s correlations are observed to smoothly extend this pi-pi Rinv behavior for the pp system up to about three times higher kT than the kT range measured in pi-pi correlations
Elliptic flow from collision geometry and rescattering
No full textCalculations of elliptic flow based on two initial state models of Au+Au collisions at √s=200 GeV/n coupled with a hadronic rescattering calculation are presented. The two initial state models used are a thermal model and a partonic model. Results from these calculations are compared with experiments and it is found that both initial state models give satisfactory representations of elliptic flow measurements, provided that the rescattering is started early enough in the collision process. It is also found that the present hadronic model studies do not show the jet suppression observed experimentally
ГУМАНИЗМ И ГУМАНИЗАЦИЯ СОВРЕМЕННОГО ОБРАЗОВАТЕЛЬНОГО ПРОСТРАНСТВА РОССИИ
No full textThe paper is aimed at analyzing the problem of education as factor of humanization of society; it reveals the criterion of humanity and humanization of social development. The author supposes it is necessary to consider humanism as a value of a person; this is a valuable core of the Russian cultural tradition. The Russian philosophical thought is deeply humanic as it focuses on a person. his happiness, sense of his life and objective reality. The Russian philosophers as Berdyaev N., Florensky P., Karelin A. criticized humanism for being the basis of European civilization. Otherwise, the Russian philosophy objected to the Soviet character of European humanism, its Eurocentrism and anthropocentrism as it became a contradiction to the nature of Christian Russian philosophy. Humanism in its global meaning is a proclamation of human inherent value that makes a valuable core of Russian cultural tradition. The modern pedagogical space concentrates on the global crisis and necessity to search for society with humanistic focus. This search results in the educational system as two components of “Humanistic triad” i.e. science and art appeared in problematic situation. The educational system had been unchangeable for a long time and responded to the social challenges. However, the latest reforms demonstrate the weakness of attempts to change the educational system by means of liberal rationalization tradition. The paper reveals the main tendencies in education and its development, which can appear to be the instrument of Russian society humanization
Hanbury-Brown-Twiss interferometry within the UrQMD transport approach
No full textIn this thesis, Hanbury-Brown-Twiss (HBT) interferometry is used together with the Ultrarelativistic Quantum Molecular Dynamics (UrQMD) to analyse the time and space structure of heavy-ion collisions.
The first chapter after the introduction gives an overview of the different types of models used in the field of heavy-ion collisions and a introduction of the UrQMD model in more detail. The next chapter explains the basics of Hanbury-Brown-Twiss correlations, including azimuthally sensitive HBT (asHBT).
Results section:
4. Charged Multiplicities from UrQMD
5. Formation time via HBT from pp collisions at LHC
6. HBT analysis of Pb+Pb collisions at LHC energies
7. HBT scaling with particle multiplicity
8. Compressibility from event-by-event HBT
9. Tilt in non-central collisions
10. Shape analysis of strongly-interacting systems
11. Measuring a twisted emission geometry
This thesis covers the standard integrated HBT analyses, extracting the Pratt-Bertsch radii, at LHC energies. The analyses at these energies showed a too soft expansion in UrQMD probably related to the absence of a partonic phase in UrQMD. The most promising results in this thesis at these energies are the restriction of the formation time to a value smaller than 0.8 fm/c and furthermore, the results from the asHBT analyses. In simulations of non-central heavy-ion collisions at energies of Elab= 6, 8 and 30 AGeV the validity of the formulae to calculate the tilt angle via asHBT has been checked numerically, even for the case of non-Gaussian, flowing sources. On this basis has been developed and test in the course of this thesis that allows to measure a scale dependent tilt angle experimentally. The signal should be strongest at FAIR energies.In dieser Arbeit wird Hanbury-Brown-Twiss (HBT) Interferometrie benutzt um im Rahmen des Models „Ultrarelativistische Quanten Molekular Dynamik“ (UrQMD) die Raum und Zeit Geometrie von Schwerionen Kollisionen zu untersuchen.
Das erste Kapitel nach der Einleitung gibt einen Überblicke über die verschiedenen Sorten von Modellen, die im Feld zur Beschreibung von Schwerionen Kollisionen genutzt werden. Dabei wird ein besonderer Fokus auf die Beschreibung des UrQMD Modelles gesetzt da dieses für die Untersuchungen in dieser Arbeit verwendet wurde.
Das nächste Kapitel gibt eine Einführung in die Grundlagen der HBT Korrelationen und enthält auch einen Abschnitt über azimuthal sensitives HBT (asHBT), welches für diese Arbeit wichtig ist.
Resultat Kapitel:
4. Charged Multiplicities from UrQMD
5. Formation time via HBT from pp collisions at LHC
6. HBT analysis of Pb+Pb collisions at LHC energies
7. HBT scaling with particle multiplicity
8. Compressibility from event-by-event HBT
9. Tilt in non-central collisions
10. Shape analysis of strongly-interacting systems
11. Measuring a twisted emission geometry
Die Resultat Kapitel enthalten die Standard Analysen zu den HBT bei LHC Energien. Dabei zeigt sich, dass die Expansion des Mediums in UrQMD zu weich ist. Dies hängt wahrscheinlich damit zusammen, dass in UrQMD keine partonische Wechselwirkungsphase vorhanden ist. Die interessantesten Ergebnisse sind zum einen die Beschränkung der Formationszeit auf einen Wert kleiner als 0.8 fm/c und zum anderen die Resultate der asHBT Analysen. In der Simulation von semizentralen Kollisionen bei Energien von Elab= 6, 8 und 30 AGeV wurde die Anwendbarkeit der Formel zur Berechnung des Drehungswinkels im Falle von nicht-Gaußschen Quellen mit Fluss numerisch nachgewiesen. Auf dieser Grundlage haben wir ein Verfahren entwickelt und getestet, das es erlaubt einen skalenabhängigen Drehungswinkel experimentell zu messen. Das Signal für diesen Drehungswinkel sollte bei FAIR Energien am größten sein
Anode region design and focusing properties of STAR Silicon Drift Detectors
No full textThis article presents the design and reports on the performance properties of the anode region of Silicon Drift Detectors (SDD's) for the Silicon Vertex Tracker (SVT) of the RHIC STAR experiment [1]. The SVT will consist of 216 SDD's. Prototype detectors with bi--directional drift and total area 6.3\Theta6.
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