113,677 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
To Mary F. Green -- from Alice Vedder Farquhar, circa 1950s
No full textLetter written by Alice Vedder Farquhar to Mary F. Green regarding the death of Mary's mother, Edith F. Brooke Green, circa 1950s
Star trails above ALICE detector building
No full textPhotographs of the ALICE building at LHC Point 2 taken during the night with a SONY ILCE-7 using a Tamron 17-28mm f/2.8 lens on a stand. (120 x JPG taken at 18mm, f/2.8, 30 sec exposure). The frames were then blended/stacked together using a freeware software to obtain the star trails
Jet Study in Ultra-Relativistic Heavy-Ion Collisions with the ALICE Detectors at the LHC
No full textIn ultra-relativistic heavy-ion collisions at = 5.5 TeV at the ALICE experiment at the LHC, interactions between the high- partons and the hot, dense medium produced in the collisions, are expected to lead to jet energy loss (jet-quenching) resulting in changes in the jet fragmentation functions as compared to the unquenched case. In order to reconstruct jet fragmentation functions, accurate information on the jet energy, direction and momentum distribution of the jet particles is needed. This thesis presents first results on jet reconstruction in simulated Pb+Pb collisions using the ALICE detectors and a UA1-based cone jet finding algorithm which has been modified and optimised to reconstruct high- jets on an event-by-event basis. Optimisation of the algorithm parameters and methods used to suppress the large background energy contribution while maximising the algorithm efficiency, are discussed and the resulting jet energy and direction resolutions are presented. Accurate jet reconstruction will allow measurement of the jet fragmentation functions and consequently the degree of quenching and therefore provide insight on the properties of the hot and dense medium (for example the initial gluon density) created in the collisions.In ultra-relativistic heavy-ion collisions at = 5.5 TeV at the ALICE experiment at the LHC, interactions between the high- partons and the hot, dense medium produced in the collisions, are expected to lead to jet energy loss (jet-quenching) resulting in changes in the jet fragmentation functions as compared to the unquenched case. In order to reconstruct jet fragmentation functions, accurate information on the jet energy, direction and momentum distribution of the jet particles is needed. This thesis presents first results on jet reconstruction in simulated Pb+Pb collisions using the ALICE detectors and a UA1-based cone jet finding algorithm which has been modified and optimised to reconstruct high- jets on an event-by-event basis. Optimisation of the algorithm parameters and methods used to suppress the large background energy contribution while maximising the algorithm efficiency, are discussed and the resulting jet energy and direction resolutions are presented. Accurate jet reconstruction will allow measurement of the jet fragmentation functions and consequently the degree of quenching and therefore provide insight on the properties of the hot and dense medium (for example the initial gluon density) created in the collisions.This thesis presents first results on jet reconstruction in simulated Pb+Pb collisions using the ALICE detectors and a UAl-based cone jet finding algorithm which has been modified and optimised to reconstruct high-PT jets on an event-by-event basis. Optimisation of the algorithm parameters and methods used to suppress the large background energy contribution while maximising the algorithm efficiency, are discussed and the resulting jet energy and direction resolutions are presented
Alice Springs Central Business District : Traffic Management Study
No full textAlice Springs Town Council commissioned Murray F. Young and Associates (MFY) Pty Ltd to undertake a review of traffic conditions within the Town?s Central Business District (CBD). The area encompassed by this study is bounded by Stott Terrace to the south, Leichhardt Terrace to the east, Wills Terrace to the north and the Stuart Highway to the westMade available by the Northern Territory Library via the Publications (Legal Deposit) Act 2004 (NT)
Interviews with John Pearson, Harry Kidd, Jake Pfeifer, Bertha Van Newman, and Alice F. Kuiper
No full textInterviews with John Pearson, Harry Kidd, Jake Pfeifer, Bertha Van Newman, and Alice F. Kuiper. 00:00:00 - Interview with John Pearson of Prairie View, KS on June 15, 1962 00:00:23 - Song, Way Down In The Low Green Valley 00:03:48 - Song, It Was Sad When That Great Ship Went Down (Song about the Titanic) 00:06:10 - Song, Rosewood Casket 00:09:37 - Song, A Message from Home, Sweet Home 00:13:27 - Song, On The Site Of Dark and Bloody Ground 00:17:24 - Song, Beyond the Rio Grande 00:23:06 - Introduction, Harry Kidd of Prairie View, KS on June 16, 1962 00:23:30 - Coming to Kansas in a covered wagon and surviving the first winter 00:32:05 - Foraging for food 00:33:07 - The local grist mill 00:34:49 - Farm machinery 00:39:12 - Spinning and weaving at home for cloth 00:42:05 - Life on the homestead 00:46:40 - Local Sioux population 00:51:00 - Local animal populations 00:53:50 - Personal accidents and injuries 01:05:08 - Prairie Fires 01:12:08 - Introduction, Jake Kuiper of Prairie View, KS 01:12:26 - Parents immigrating from Holland 01:13:05 - Dutch nursery rhymes and proverbs 01:17:14 - Introduction to song sung by person from Great Bend, KS 01:17:53 - Song, The Ship That Never Returned 01:18:55 - Introduction, Bertha Van Newman of Prairie View, KS on June 20, 1962 01:19:33 - Family immigrating from Holland and homesteading in Kansas 01:22:48 - Dutch proverbs, riddles, poems, and superstitions 01:27:39 - Her grandfather and his death 01:29:51 - Community celebrations 01:32:21 - Introduction, Alice F. Kuiper of Prairie View, KS 01:32:33 - Song, My name is Jan Johnson 01:33:11 - Song, Sweet Rosie O\u27Gradyhttps://scholars.fhsu.edu/sackett/1063/thumbnail.jp
Sunbonnet Sue quilt, by Alice Jane Tranter Allen
No full textImage of Sunbonnet Sue quilt created in 1934 by Alice Jane Tranter Allen. Also includes questionnaires describing the quilt completed by Karen F. Parkinson as part of the Utah Quilt Guild\u27s documentation days held from 1988-1994. Alice Jane Tranter Allen was born on September 15, 1868 in Nephi, Utah. She married Thomas E. Allen on November 2, 1892 in Salt Lake City, Utah. They had six children. This quilt was made in Coalville, Utah. Mrs. Allen was an active quilter in the LDS Churc
Appliquéd Iris quilt, by Alice Jane Tranter Allen
No full textImage of Appliquéd Iris quilt created in 1929 by Alice Jane Tranter Allen. Also includes questionnaires describing the quilt completed by Karen F. Parkinson as part of the Utah Quilt Guild\u27s documentation days held from 1988-1994. Alice Jane Tranter Allen was born on September 15, 1868 in Nephi, Utah. She married Thomas E. Allen on November 2, 1892 in Salt Lake City, Utah. They had six children. This quilt was made in Coalville, Utah. Mrs. Allen was an active quilter in the LDS Churc
- …
