214,904 research outputs found
The ALICE TPC : a large 3-dimensional tracking device with fast readout for ultra-high multiplicity events
No full textThe design, construction, and commissioning of the ALICE Time-Projection Chamber (TPC) is described. It is the main device for pattern recognition, tracking, and identification of charged particles in the ALICE experiment at the CERN LHC. The TPC is cylindrical in shape with a volume close to 90 m3 and is operated in a 0.5 T solenoidal magnetic field parallel to its axis.
In this paper we describe in detail the design considerations for this detector for operation in the extreme multiplicity environment of central Pb–Pb collisions at LHC energy. The implementation of the resulting requirements into hardware (field cage, read-out chambers, electronics), infrastructure (gas and cooling system, laser-calibration system), and software led to many technical innovations which are described along with a presentation of all the major components of the detector, as currently realized. We also report on the performance achieved after completion of the first round of stand-alone calibration runs and demonstrate results close to those specified in the TPC Technical Design Report
Charakterisierung von dem ALice-Tpc-ReadOut-Chip
No full textDie vorliegende Arbeit beschäftigt sich mit der Charakterisierung des ALTRO Chips (ALICE TPC Readout), der ein integraler und wichtiger Bestandteil der Auslesekette des TPC (Time Projection Chamber) Detektors von ALICE (A Large Ion Collider Experiment) ist. ALICE ist ein Experiment am noch im Bau befindlichen LHC (Large Hadron Collider) am CERN mit der zentralen Ausrichtung, Schwerionenkollisionen zu untersuchen. Diese sind von besonderem Interesse, da durch sie ein experimenteller Zugriff zu dem QGP (Quark Gluon Plasma) existiert, dem einzigen vom Standardmodell vorhergesagten Phasenübergang, der unter Laborbedingungen erreichbar ist. Im Jahr 2004 wurden Messungen an einem Teststrahl am CERN PS (Proton Synchrotron) durchgeführt. Der Prototyp wurde voll mit FECs bestückt, was 5400 Kanälen entspricht und einer anderen Gasmixtur (Ne/N2/CO2 90%/5%/5%) befüllt. Für das optimale Leistungsverhalten der ALICE TPC muß der Digitalprozessor im ALTRO, bestehend aus vier Berechnungseinheiten, mit den passenden Werten konfiguriert werden. Der Datenfluss beginnt mit dem BCS1 (Baseline Correction and Subtraction 1) Modul, das systematische Störungen und die Grundlinie entfernt. Da der ALTRO kontinuierlich das anliegende Signal abtastet, entfernt es automatisch langsame Grundlinienveränderungen, die Beispielsweise durch Temperaturänderungen auftreten können. Gefolgt von dem TCF (Tail Cancellation Filter), der den Schweif des langsam fallenden, vom PASA generierten Signals entfernt. Um die nichtsystematischen Störungen der Grundlinie zu entfernen, folgt die BCS2 (Baseline Correction and Subtraction 2), die auf einer gleitenden Mittelwertsberechnung mit Ausschluß von Detektorsignalen über einen doppelten Schwellenwert basiert. Die finale Einheit für die Signalverarbeitung ist die ZSU (Zero Suppression Unit), die Meßpunkte unterhalb eines definierten Schwellwertes entfernt. Hier wird der weg beschrieben die TCF und BCS1 Parameter aus vorhandenen Detektordaten zu extrahieren. Während der Analyse der Daten von kosmischen Teilchen fiel bei Signalen mit hoher Amplitude (>700 ADC) eine zusätzliche Struktur in dem Schweif auf. Der Monitor wurde deswegen mit einem gleitenden Mittelwertfilter erweitert, worauf sich diese Struktur auch in kleineren Signalen (> 200 ADC) zeigte. Dieses Signal wird von Ionen erzeugt, die zur Kathode oder zu den Pads driften, bisher ist jedoch weder die Streuung der Elektronenlawine an der Anode, noch die Variationsbreite in den erzeugten Elektronlawinen verstanden oder gemessen worden. Eine erfolgreiche Messung, sowie Charakterisierung wird in dieser Arbeit beschrieben. Im Jahr 2005 im Sommer beginnt der Einbau der Gaskammern der TPC in ALICE, die Elektronik folgt am Ende dieses Jahres. Parallel hierzu wurde der Prototyp der TPC wieder in Betrieb genommen und im Frühling wird ein kompletter Sektor mit der Detektorelektronik ausgestattet. An diesen zwei Aufbauten wird die ALTRO Charakterisierung fortgeführt, verfeinert und komplettiert
ALICE Industry Award
No full textALICE Industry Awards Ceremony on Monday 9 November 2020, during ALICE week. The 5 companied selected by the Industry Award Committee are : FEDD (Saint Alvère, France), Tower Semiconductor (Migdal Haemek, Israel), Etesian Semiconductor (Ramat Yishai, Israel), C-ON Tech (NamdongGu Incheon, South Korea) and IMEC (Leuven, Belgium
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[Photograph of Mary Alice Rice c. 1928]
No full textPhotograph of Mary Alice Rice c. 192
Alice Miel and Democratic Schooling: An Early Curriculum Leader\u27s Ideas on Social Learning and Social Studies
No full textAlice Miel, a nationally prominent curriculum development scholar-practitioner at Teachers College of Columbia University for some three decades (1942-1971), frequently has been overlooked in research on the nature and evolution of the curriculum field and the progressive education movement. Furthermore, her contributions have been overlooked even as attention to women in the curriculum field and in educational history has risen. This study addresses this oversight.
Miel became a leading figure in the curriculum field largely on the basis of her progressive-era advocacy and practice of democratic social learning as a primary goal of schooling in the United States. This study explores major influences on her ideas, her understandings of democratic concepts and principles, and her application of these concepts and principles both in her own college classroom and in her research on childhood education. It also explores Miel\u27s notions of the elementary school social studies :urriculum and situates those notions within the context of the conventional wisdom of her day regarding a discipline-centered curriculum.
In a broader context, this study contributes to the body of curriculum history scholarship. According to Kliebard (1992), for example, curriculum history often deals with the relationship between social change and changing ideas and contains significant social and cultural artifacts of knowledge that have become embodied in the curriculum of schools. Davis (1976, 1977) characterizes curriculum history as a reflective enterprise for curriculum workers that contributes to their understanding of present courses of study and of the professional field by lending a framework for thoughtful deliberation of what the schools should teach. With these observations in mind, Miel\u27s work may be understood as both artifact of curriculum history and as mindful reflection, situated within a particular social and historical context, on democratic meanings and processes. Biographies of Caswell, Taba, Tyler, Schwab, Kilpatrick, Rugg, Bobbitt, Zirbes, Stratemeyer, and others have yielded significant insights. In addition, Seguel\u27s study of early curriculum leaders (1966) constitutes an important theoretical contribution to the field. The study of Miel\u27s life and work adds to this body of knowledge
Production of W± bosons in the semi-muonic channel at forward rapidity in ALICE
No full textHeavy-ion collisions are the unique tool available to investigate strongly interacting matter at high energy density where the formation of a new phase of matter −the quark gluon plasma is expected. The ALICE Muon Spectrometer is specifically designed to study this phase of matter using muonic decay channels in the acceptance region between −4.0 ≤ η ≤ −2.5 (forward rapidity). ALICE has the unique ability to track and identify particle in a wide rapidity range where in the central barrel (| η |< 0.9) the particles are tracked and identified from a transverse momentum (PT ) as low as PT ∼100 MeV/c up to PT ∼100 GeV/c with the PT resolution of about 1% at 50 GeV/c and the impact parameter resolution of about 65 microns at 1 GeV/c. The Forward Muon Spectrometer is composed of 10 tracking chambers, 4 trigger chambers, absorbers as well as the 3 Tm dipole magnet. The PT resolution of the Spectrometer is ∼1% at 20 GeV/c and ∼4% at 100 GeV/c and the muons are tracked from PT as low as ∼500 MeV/c up to 100 GeV/c. This study focuses on the analysis of W± → μ± + νμ+ (ν ̄μ− ) Monte-Carlo data generated using PYTHIA 6.4.21 in the AliROOT framework in proton-proton collisions at 8 TeV and proton-proton experimental data at 7 TeV at forward rapidity. In the analysis of the experimental data the efficiency of the Tracking Chambers is 81±0.5% and 95±0.5% for the Muon Trigger Chambers, while in the simulation the efficiency of the Muon Tracker is ∼80% for the realistic case based on the conditions of 2011 PbPb data taking period and between 95-100% for the ideal case. This study exploits this tracking attributes of ALICE to investigates the feasibility of extracting W± boson in its muonic decay channel at these energies
Validation of the 65 nm TPSCo CMOS imaging technology for the ALICE ITS3
No full textDuring the next Long Shutdown (LS3) of the LHC, planned for 2026, the innermost three
layers of the ALICE Inner Tracking System will be replaced by a new vertex detector composed of curved ultra-thin monolithic silicon sensors. The R&D initiative on monolithic sensors of the CERN Experimental Physics Department, in cooperation with the ALICE ITS3 upgrade project, prepared the first submission of chip designs in the TPSCo 65 nm technology, called MLR1 (Multi Layer Reticle). It contains four different test structures with different process splits and pixel designs. These proceedings illustrate the first validation of the technology in terms of pixel performance and radiation hardness
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[Photograph of Mary Alice Rice c. 1920s-1930s]
No full textPhotograph of Mary Alice Rice c. 1920s-1930
Recommended from our members
[Photograph of Mary Alice Rice c. 1920s-1930s]
No full textPhotograph of Mary Alice Rice c. 1920s-1930s
Recommended from our members
[Photograph of Mary Alice Rice c. 1920s-1930s]
No full textPhotograph of Mary Alice Rice c. 1920s-1930s
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