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E ALICE Silicon Pixel Detector System COMENIUS UNIVERSITY, BRATISLAVA, SLOVAKIA Faculty of Mathematics, Physics and Informatics e ALICE Silicon Pixel Detector System Svetozár Kapusta Under the supervision of Peter Choula CERN 2009 I declare that I have elaborated this thesis independently, citing all information sources that Iused. CERN, Svetozár Kapusta “e observer, when he seems to himself to be observing a stone, is really, if physics is to be believed, observing the effects of the stone upon himself.” Bertrand Russell For my parents Contents List of Abbreviations ix 1Introduction 1 1.1 eQuark-GluonPlasma................................ 3 2 e Large Hadron Collider and its Experiments 7 2.1 eLargeHadronCollider................................ 7 2.2 Acceleratorphysics.................................... 7 2.3 eLargeHadronColliderdesignparameters.................... 9 2.4 eLHCExperiments................................... 13 2.4.1 eATLASDetector............................... 14 2.4.2 eCMSDetector................................ 14 2.4.3 eALICEDetector............................... 15 2.4.4 eLHCbDetector................................ 15 2.4.5 eTOTEMDetector............................... 16 2.4.6 eLHCFDetector................................ 17 2.5 eLHCStartupandcurrentstatus........................... 17 3 A Large Ion Collider Experiment (ALICE) 21 3.1 eALICECentralBarrel................................. 22 3.1.1 InnerTraingSystem.............................. 23 i ii CONTENTS 3.1.2 TimeProjectionChamber........................... 24 3.1.3 ACORDE..................................... 24 3.1.4 TimeOfFlightdetector............................. 25 3.1.5 HighMomentumParticleIdentificationDetector.............. 25 3.1.6 TransitionRadiationDetector......................... 25 3.1.7 PhotonSpectrometer.............................. 25 3.1.8 ElectromagneticCalorimeter.......................... 26 3.2 ForwardDetectors..................................... 26 3.3 eForwardMuonSpectrometer............................ 26 3.4 OnlineSystems....................................... 27 3.4.1 ExperimentalControlSystem......................... 27 3.4.2 Trigger....................................... 27 3.4.3 DataAcquisition................................. 27 3.4.4 High-LevelTrigger................................ 28 3.4.5 DetectorControlSystem............................ 28 4 e ALICE Silicon Pixel Detector 29 4.1 SPDLayout......................................... 30 4.2 e ALICE1LHCb Chip.................................. 34 5 e Silicon Pixel Detector Testbeams and Commissioning 39 5.1 Assemblytestbeam.................................... 40 5.1.1 ExperimentalSetup............................... 40 5.1.2 X-Ytable..................................... 41 5.1.3 Results....................................... 41 5.2 Laddertestbeam...................................... 44 5.2.1 Experimentalsetup............................... 44 CONTENTS iii 5.2.2 Results....................................... 45 5.3 Highmultiplicitytestbeam................................ 49 5.3.1 ExperimentalSetup............................... 49 5.3.2 PCI-2002 . ....................... 51 5.3.3 Results....................................... 51 5.4 JointITStestbeam..................................... 57 5.4.1 ExperimentalSetup............................... 57 5.4.2 DataAcquisitionandDetectorControlSystem............... 59 5.4.3 Trigger....................................... 60 5.4.4 ResultsandOfflineAnalysis.......................... 60 5.5 SimulationoftheSiliconPixelDetector........................ 61 5.6 SPD Commissioning and Cosmic runs in 2007-2009 . 63 5.6.1 Calibrationandalignment........................... 65 6 e ALICE Detector Control System 69 6.1 IntroductiontoControlSystems............................ 69 6.1.1 JCOP........................................ 70 6.2 PVSS............................................. 72 6.3 ALICEDCS.......................................... 76 6.4 Systemlayout........................................ 77 6.4.1 Fieldlayer..................................... 78 6.4.2 Controllayer................................... 78 6.4.3 Supervisorylayer................................. 79 6.5 eFiniteStateMaines................................ 79 6.6 Partitioning......................................... 80 6.7 eUserInterface..................................... 81 iv CONTENTS 6.8 eJCOPFRAMEWORK.................................. 84 6.9 Dataflow.......................................... 85 6.9.1 eSynronizationDataFlowinALICEDCS................ 87 6.9.2 eControlsDataFlowinALICEDCS..................... 88 6.10ALICEDCSdatabase.................................... 92 6.10.1Configurationdatabase............................. 94 6.10.2ArivalDatabase................................ 98 6.10.3PVSSAriving.................................. 99 6.10.4PVSS-OracleAriving............................. 100 6.10.5PVSS-OracleArivingPerformance..................... 103 6.10.6ALICEDCSdatabaseoperationandmaintenance...............105 6.11AMANDA......................................... 110 6.12Systemcommissioningandfirstoperationexperience................ 113 7 Conclusions 115 Bibliography 118 List of Figures 128 List of Tables 137 List of Publications 138 Anowledgments 142 Názov práce: Kremíkové pixlové detektory pre experiment ALICE. Autor: Svetozár Kapusta Školitel: Peter Choula Klučove slová: testbeam,SPD,ALICE,DCS Veľký hadrónový zrážač (LHC) sa momentálne blíži svojmu opätovnému spusteniu v Európskom Centre pre Jadrový Výskum (CERN). LHC bol po prvý krát spustený 10-teho Septembra 2008. Spustenie bolo obrovským úspeom, pretože už v rámci jednej hodiny od vpustenia zväzkov do LHC sa podarilo previesť prvý zväzok celým urýľovačom v jednom smere a ešte v ten istý deň v opačnom smere. Počiatočná eufória bola však prerušená elektriou nehodou 19-teho Septembra počas zvyšovania nominálneho prúdu v dipóle v Sektore 34 zo 7 kA na 9,3 kA (čo zodpovedá zväzku s energiou 5,5 TeV). Táto nehoda spôsobila meanié škody, únik hélia a značné oneskorenie očakávaný kolízií na LHC. Experiment ALICE bude využívať zrážky urýlený častíc vytváraný na LHC za účelom študovania správania sa silne interagujúcej hmoty v extrémny hustotá a vysoký teplotá. Kremíkový pixlový detektor (SPD) tvorí dve najvnútornejšie vrstvy vnútorného dráhovacieho systému (ITS) detektora ALICE. Dve vrsty cylindriého tvaru sa naádzajú 3,9 cm a 7,6 cm od bodu interakcií (IP). Jednou z hlavný úloh detektora SPD je poskytovať čo najpresnejšiu polohu elektriy nabitý častíc, ktoré ním preleteli. Táto informácia je mimoriadne dôležitá pre analýzu ťažký kvarkov rozpadajúci sa slabou interakciou, pretože typiým znakom týto rozpadov sú sekundárne vertexy vzdialené len niekolko stoviek mikrometrov od primárny vertexov. Pri zrážka ťažký iónov olova môže hustota častíc dosiahnuť až 80 dráh na cm2 vo vnútornej vrstve SPD. SPD dosahuje polohové rozlíšenie okolo ≈12 μm v smere rϕ aokolo≈70 μm v smere z. Obsadenosť kanálov detektora SPD sa očakáva v rozmedzí od 0,4% do 1,5% čo umožnuje detektoru SPD byť výnikajúcim detektorom na meranie násobnosti nabitý častíc v oblasti pseudorapidity |η| < 2. Ďaľšou jedinečnou vlastnosťou detektora SPD je, že skombinovaním všetkýjehozrekonštruovanýdráhmôžemezískaťhrubýodhadpolohyprimárnehovertexu. JednouzvelkývýzievjeajvysokéobmedzenienapoužitémateriályzktorýjeSPDpostavený (<1% z radiačnej dĺžky na jednu vrstvu) za účelom čo najmenšieho ovplyvňovania traverzujúci častíc. Kremíkový senzor a jeho vyčítavajúci čip majú spolu celkovú hrúbku iba 350 μm a spojenia pre signály medzi nimi a riadiacou a vyčítavacou elektronikou sú z hliníka. V tejto dizertačnej práci prezentujem môj prínos k projektu ALICE SPD, zhrniem fázy vývoja, zhotovovania a testov projektu ALICE SPD. Môj prínos k projektu ALICE DCS je ťiež predstavený. V uplynulý roko kolaborácia ALICE SPD uskutočnila štyri testy so zväzkami urýlený častíc. Hlavným cieľom týto testov bola kontrola funkčnosti čipov a príslušnej elektroniky, kremíkový senzorov, vyčítavajúcej elektroniky a takisto aj systémov online - DAQ, Trigger a DCS spolu aj s i programovým vybavením a taktiež aj systémov offline. Prototypy vyčítavajúci pixlový čipov a kremíkový senzorov boli testované počas odlišný podmienok (určovanie prahu detekcie, rôzne naklonenia vzhľadom na zväzok, meranie detekčnej účinnosti v závislosti od veľkosti záverného napätia, atď.). Okrem vyčítavajúci pixlový čipov a kremíkový sen- zorov s veľkou hrúbkou boli takisto testované detektory s malou hrúbkou a taktiež aj 5-čipové detektory (tzv. ladder) tak, ako boli navrhnuté pre experiment ALICE. Počas a najmä po testo so zväzkami urýlený častíc som vyvíjal programové vybavenia na overenie kvality zberaný dát, na zlúčenie dvo dátový tokov z dvo rôzny vrstiev a typov detektora SPD, na hľa- danie a možné odstránenie pixlov s nadmiernym šumom, na koreláciu priestorový koordinát z rôzny vrstiev detektora SPD, na komplexnú offline analýzu nameraný dát, obsahujúcu zobrazenie zásahov detektorov SPD, integrálne zobrazenie zásahov detektorov SPD, analýzu event po evente, určenie detekčnej účinnosti, násobnosti častíc, veľkosti klastrov, atď. Prototyp finálnej vyčítavajúcej elektroniky a dvo finálny 5-čipový detektorov bol tiež otestovaný za overenia funkčnosti programového vybavenia online systémov DAQ, Trigger a DCS a systému offline. Konfigurácia, vyčítavanie a ovládanie detektora SPD vykonávané pomocou Ovládacieho sys- tému detektora (DCS). Ako člen tímu pre Koordináciu ovládacieho systému experimentu ALICE (ACC) som mal možnosť podieľať sa na koncepcii, vývoji, uvedení do
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