CERN-THESIS-2005-007 05/08/2004 Charles University in Prague Faculty of Mathematics and Physics DIPLOMA THESIS Zde·nkaBroklov¶a Simulations of ATLAS silicon strip detector modules in ATHENA framework Institute of Particle and Nuclear Physics Supervisor: Dr. Zden·ekDole·zal Co-supervisor: Dr. Peter Kody·s Study programme: Physics Nuclear and Subnuclear Physics I would like to express my great gratitude to my supervisor Dr. Zden·ek Dole·zalfor his professional feedback and help during my work. I would like to thank also to Dr. Peter Kody·sand Pavel Rezn¶³·cekwho· have introduced me into the ATLAS o²ine software and helped me to solve problems with this complex software system. Many thanks belong also to many people from ATLAS o²ine software community, mainly to Grant Gor¯ne and Thijs Cornelissen, for their advice and \expert's" support and to Carlos Escobar for his cooperation. Last, but not least, I am very grateful to Jan Koupil for his patience he had with me and for his help with language aspect of this thesis. Prohla·suji,·zejsem svou diplomovou pr¶acinapsala samostatn·ea v¶yhradn·e s pou·zit¶³mcitovan¶ych pramenºu.Souhlas¶³mse zapºuj·cov¶an¶³mpr¶ace. I declare that I wrote my diploma thesis independently and exclusively with the use of the cited sources. I agree with lending this thesis. Prague, 5th August 2004 Contents Introduction 6 1 Detector ATLAS 8 1.1 Purpose of ATLAS detector . 8 1.2 ATLAS detector construction . 9 1.3 SCT module . 12 2 Momentum measurement in the ATLAS Inner Detector 16 2.1 Momentum resolution . 17 2.2 Influence of material . 23 3 ATLAS o²ine software 25 3.1 Athena . 26 3.2 CMT - the Con¯guration Management Tool . 29 3.3 First steps with Athena . 30 3.3.1 The CMT con¯guration . 30 3.3.2 Installation and running jobs . 32 3.3.3 Releases and tagging a package . 33 3.3.4 Checking out and modifying a package . 34 3.4 ASK - the Athena Startup Kit . 35 3.5 Other Athena framework features . 36 3.5.1 Data Flow . 36 3.5.2 Histograms and Ntuples . 38 3.5.3 Tools . 40 3.5.4 Detector Description . 40 3.6 SCT CTB simulation . 41 4 SCT end-caps modules in the Athena framework 47 4.1 The Inner Detector description in Athena . 47 4.2 Raw and readout geometry veri¯cation . 53 4.3 Geometry and materials validation . 58 3 Conclusion 61 Appendices 66 A SCT CTB simulation jobOptions ¯les 67 B SCT CTB simulation Python scripts 74 4 N¶azevpr¶ace: Simulace vlastnost¶³k·rem¶³kov¶ychstripov¶ychdetektorºupro experiment ATLAS v prost·red¶³Athena Autor: Zde·nkaBroklov¶a Katedra: Ustav¶ ·c¶asticov¶ea jadern¶efyziky Vedouc¶³diplomov¶epr¶ace: RNDr. Zden·ekDole·zal,Dr., UCJF· E-mail vedouc¶³ho: Zdenek.Dolezal@m®.cuni.cz Abstrakt: P·redlo·zen¶adiplomov¶apr¶acese zab¶yv¶avlastnostmi k·rem¶³kov¶ych stripov¶ych detektorºu(SCT) pro detektor ATLAS a vytvo·ren¶³mjejich softwarov¶ehomodelu. Prvn¶³·c¶astt¶etopr¶acestru·cn·eshrnuje charakteristiky cel¶ehodetektoru ATLAS s dºura- zem na vlastnosti vnit·rn¶³hodetektoru, jeho·zsou·c¶ast¶³tvo·r¶³i k·rem¶³kov¶estripov¶edetektory. Krom·ekonstruk·cn¶³ch vlastnost¶³si v·s¶³m¶ai schopnosti vnit·rn¶³hodetektoru m·e·ritmoment hybnosti nabit¶ych ·c¶astic. Druh¶a·c¶astpr¶aceobsahuje popis z¶akladn¶³ch prvkºuprost·red¶³ Athena a o²ine softwaru experimentu ATLAS celkov·e.Prost·red¶³Athena je vyv¶³jenopro simulov¶an¶³vlastnost¶³a anal¶yzudat z¶³skan¶ych z cel¶ehodetektoru ATLAS. Tento text je ur·cenpro prvn¶³sezn¶amen¶³s cel¶ymprost·red¶³m. Konkr¶etn¶³mp·r¶³nosemt¶etopr¶aceje implementace nov¶ehogeometrick¶ehomodelu SCT end-cap modulºu,jeho podrobn¶akontrola a pod¶³lna p·r¶³prav·ecel¶ehoSCT subsyst¶emu pro simulaci a zpracov¶an¶³dat z kombinovan¶ehotestbeamu (CTB) konan¶ehov l¶et·e2004. V podm¶³nk¶ach CTB byla ov·e·rov¶anafunk·cnosta spr¶avnostcel¶ehosimula·cn¶³ho·ret·ezceod vytvo·ren¶³ geometrie a simulace prºuchodu ·c¶asticea·zpo zpracov¶an¶³ simulovan¶eodezvy detektorºua rekonstrukci dr¶ahy ·c¶astice. Kl¶³·cov¶aslova: ATLAS SCT, k·rem¶³kov¶ydetektor, o²ine software, prost·red¶³Athena Title: Simulations of ATLAS silicon strip detector modules in ATHENA framework Author: Zde·nkaBroklov¶a Department: Institute of Particle and Nuclear Physics Supervisor: Zden·ekDole·zal,Ph.D., IPNP Supervisor's e-mail address: Zdenek.Dolezal@m®.cuni.cz Abstract: This diploma thesis deals with properties of the silicon strip detector (SCT) modules of the ATLAS detector and building their software model. First part of the thesis consists of a brief overview of the ATLAS detector properties and focuses on the Inner Detector and its SCT part. Besides mechanical characteristics, analysis of capability to measure the charged particle momentum is placed there as well. Main features of the Athena framework and of the entire ATLAS o²ine software can be found in the further part. Athena framework is developed for simulations and future analyzing of the whole ATLAS measured data. This text is intended mainly for Athena newcomers. The main contribution of this thesis to ATLAS o²ine software preparation is im- plementation of the new SCT end-cap modules' geometry model, its detailed checking and preparation of the necessary software component for whole SCT subsystem for the Combined Testbeam (CTB - summer 2004). We perform checking the functionality of the whole simulation sequence from geometry model building and simulation of particle passage through it to processing of the simulated detector response and reconstruction of the particle track. Keywords: ATLAS SCT, silicon detector, o²ine software, Athena framework Introduction A new hadron collider (LHC { Large Hadron Collider) is being built in the CERN (Centre Europeen pour Recherche Nucleare). For this accelerator four large experiments are prepared and one of them is the ATLAS (A Toroidal LHC ApparatuS). This diploma thesis considers mostly the issue of the ATLAS Inner De- tector. The Inner Detector consists of highly precise silicon pixel and strip detectors and continuous transition radiation detectors. Its main function is to measure the momentum and vertex position of charged particles. The strip detector part is usually called the SemiConductor Tracker (SCT). Up to now production of all subsystems of ATLAS has been already started. That's why the interest of many physicists and other people involved in the ATLAS collaboration turned away from designing and production of the detectors to preparation for the future analysis of the data measured on the ATLAS. Massive development is now concentrated on preparation of the software tools for data manipulation and analysis called \o²ine software". This is a huge software project involving several tens of programmers and many physicists and engineers who ensure including the \proper physics" into the software. The main goal of this thesis was to attach our workgroup to this activity, ¯nd out the ways how to use the entire prepared system and how to con- tribute to its development. Main focus was put on the preparation for the Combined Testbeam (CTB) which takes place in the summer 2004. It will be a demonstration of the functionality and correctness of the prepared software and a good example how the whole ATLAS will be operated. Wide expe- rience with properties of the silicon strip detector modules and especially the end-cap ones, which Prague SCT team gained in the past, aimed our work naturally to the preparation of the SCT part of the whole CTB setup. There existed only a very poor description of the SCT end-cap modules, so improving the geometric description of them was the ¯rst step in building description of the whole SCT testbeam setup. The new description was val- 6 Introduction 7 idated using several methods. Further functionality of the data simulation and analysis sequence for this subsystem was checked. In this thesis a brief description of the whole ATLAS detector and its SCT subsystem can be found (see chapter 1) as well as some simple analyses of the momentum measurement ability of the ATLAS Inner Detector (see chapter 2). The large part of text is covered by the description of the main features of the ATLAS o²ine software and further tools used for its devel- opment and usage placed in the chapter 3. This part is aimed at people who start using this very complex system and hopefully should help them making their ¯rst steps. The processes of implementation and validation of the SCT end-cap modules geometric model are described at the end of this thesis. Chapter 1 Detector ATLAS 1.1 Purpose of ATLAS detector The ATLAS (A Toroidal LHC ApparatuS) detector system is designed to exploit the full potential of the Large Hadron Collider (LHC) [1]. This collider is built at CERN (Centre Europeen pour Recherche Nucleare) { the world's largest international particle physics laboratory. The laboratory is placed in Switzerland near Geneve but numerous facilities are built behind the border, in France. The LHC is a proton-proton collider with a 14 TeV center of mass energy and design luminosity about 1034 cm¡2s¡1. The beam bunch-crossing interval is 25 ns and in the design luminosity we expect more than 20 interactions in each crossing. Due to high luminosity and crossing frequency LHC o®ers a large range of physics opportunities and accelerator and detector building presents challenge for many physicists and engineers. The major focus of the ATLAS detector is the mass origin at the elec- troweak scale. The detector sensitivity is optimized for the widest possible Higgs boson mass range.