Geometr´Ia Del Detector CMS Reconstruida Con El Sistema De Alineamiento Link
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Departamento de F´ısica Moderna (Universidad de Cantabria) y Instituto de F´ısica de Cantabria (CSIC–Universidad de Cantabria) Geometr´ıa del detector CMS reconstruida con el sistema de alineamiento Link. Memoria presentada por Mar Sobr´on Sa˜nudo para optar al grado de Doctor y dirigida por Dr. Teresa Rodrigo Anoro y Dr. Celso Mart´ınez Rivero Santander, Septiembre 2009 A mi familia. Los doctores abajo firmantes certifican que la memoria presentada ha sido realizada por Da. Mar Sobr´on Sa˜nudo, bajo nuestra direcci´on, y constituye la Tesis que presenta para optar al grado de Doctora en Ciencias F´ısicas. Titulo de la memoria: CMS detector geometry reconstructed with the Link alignment system Dra. Teresa Rodrigo Anoro Catedr´atica de F´ısica At´omica, Nuclear y Molecular Universidad de Cantabria Dr. Celso Mart´ınez Rivero Investigador del Consejo Superior de Investigaciones Cient´ıficas Instituto de F´ısica de Cantabria Contents Introduction 13 1 The LHC and the CMS experiment 17 1.1 The Large Hadron Collider . ........................ 17 1.2TheCompactMuonSolenoid....................... 23 1.3PhysicsinCMS............................... 39 2 The CMS Alignment System 45 2.1Alignmentstrategy............................. 45 2.2Trackerlaseralignmentsystem...................... 50 2.3Muonbarrelalignment........................... 52 2.4Muonendcapalignment.......................... 56 2.5Linkalignmentsystem........................... 59 2.6AlignmentelementsinstalledfortheMTCC............... 75 2.7Magneticfieldandradiationenvironment................. 75 3 Simulation and Reconstruction Software 81 3.1COCOASoftwaredescription....................... 82 3.2DescriptionoftheOpticalsystem..................... 83 3.3Validationofthesoftware......................... 90 3.4Conclusions................................. 97 4 Calibration of components 99 4.1Electrolytictiltsensors........................... 99 4.2Opticaldistancemetersensors....................... 104 4.3Contactdistancemetersensors....................... 107 4.4Temperatureprobes............................. 109 4.5 Amorphous Silicon Position Detectors (ASPD) . ............ 110 4.6Calibrationofcarbonfiberstructures................... 113 4.7Conclusions................................. 122 5 Data quality 125 5.1MagnetconditionsandSystemperformance............... 126 5.2Descriptionof1Dmeasurements...................... 129 5.3Overviewofresultsfromsystemdata................... 132 5.4Individualsensorsdataanalysis...................... 138 2 Contents 5.5Lasersystemandphoto–sensorsinformation............... 152 5.6Conclusions................................. 154 6 Geometrical Reconstruction 157 6.1Systemdescription............................. 157 6.2MTCCdatasets............................... 160 6.3GeometricalfitsatB=0TinMTCCphaseI............... 161 6.4FitswithincreasingBfieldinphaseI................... 166 6.5GeometryreconstructionusingMTCCphaseIIdata.......... 169 6.6ComparisonbetweenMTCCphaseIandphaseII............ 172 6.7CRAFT08dataset............................. 173 6.8DetectorgeometryfromCRAFT08data................. 173 6.9Systemperformance............................ 177 6.10Conclusions................................. 179 7 Summary and Conclusions 185 Bibliography 199 I. Introducci´on i II. Resumen y Conclusiones v List of Figures 1.1ViewoftheLHCanddetectorsattheSwiss–Frenchborder....... 18 1.2TheLHCandexperimentsscheme..................... 19 1.3 Accelerator complex ............................ 20 1.4 Overview of the cross sections of some major process at the LHC . 22 1.5AperspectiveviewoftheCMSdetector................. 24 1.6AsliceoftheCMSbarrelintheX–Yplane............... 25 1.7schematicviewoftheCMSmagnetsystem................ 26 1.8CrosssectionoftheCMStracker..................... 27 1.9LayoutoftheCMSECALdetector.................... 30 1.10LocationoftheHadroncalorimeterintheCMSdetector........ 32 1.11LayoutoftheCMSbarrelmuondetector................. 34 1.12SketchofaDTchamber.......................... 35 1.13 View of the endcap muon system in a quarter of the CMS detector . 36 1.14LayoutofaCSCmuonchamber...................... 37 1.15ArchitectureoftheLevel–1Trigger.................... 39 1.16 Higgs boson production channel cross sections as a function of mass . 41 1.17 Higgs boson decay channel branching ratios as a function of mass . 41 1.18 Histograms of the µ+µ− invariant mass assuming an initial detector not perfectlyaligned.............................. 43 2.1 The muon momentum resolution as a function of the transverse momentum 46 2.2Schematicviewofthealignmentsystem................. 49 2.3OverviewofthetrackerLaserAlignmentSystem............. 51 2.4 Schematic view of the connexion between the TK and the muon alignment 51 2.5Barrelalignmentsystemopticalnetwork................. 54 2.6SchematicviewofaDTchamberwithcornerblocks........... 55 2.7PicturesoftheMABsinthedetector................... 56 2.8 Visualization of the geometry and components of the muon endcap align- mentsystem................................. 57 2.9Sketchofthetwotypesofendcaplaserlines............... 57 2.10PictureofoneSLMoftheendcapalignment............... 59 2.11Linkalignmentelementsinaquarterofplane.............. 61 2.12DetailedpictureofaLaserLevelwithallthecomponents........ 63 2.13SketchoftheLDhangingfromtheTransferPlates........... 64 2.14SketchandpictureofaTransferPlateaswasfortheMTCC...... 65 4 List of Figures 2.15 3D drawing of the new design of the Transfer Plates and the ME1/1 zone 66 2.16PictureofaME1/2chamberwiththealignmentsensor–boxes..... 67 2.17 Pictures of the Link Disk and the Alignment Ring in the detector . 68 2.18SketchoftheLinklaserlines........................ 70 2.19SchemeoftheLinkReadoutandcontrolsystem............. 72 2.20PVSSpanelsformonitoringtheLinksystem............... 74 2.21ThealignmentelementsinstalledduringtheMTCC........... 75 2.22 Distortion in the Z direction of the first endcap disk due to the 4 T solenoid................................... 76 2.23Magneticfieldandfluxlines........................ 77 2.24RadiationdoseintheCMSdetector.................... 79 3.1 Difference between the simulated value fitted by COCOA and the nom- inal value of the Y coordinate of a ME1/2 chamber with respect to the errorinthesensorsmeasurements..................... 93 3.2 Difference between the nominal value and the simulated value fitted by COCOA of the X coordinate of the AR with respect to the error in the positionofthestructures.......................... 96 4.1 Schematic view of the tiltmeters sensors used by the Link alignment system.................................... 100 4.2Schematicviewofanopticaltriangulationsensor............ 105 4.3Schematicsofapotentiometersensor................... 107 4.4sketchandpictureofanASPDsensor................... 111 4.5AlignmentsystemcalibrationbenchattheISR............. 114 4.6PictureoftheARattheISR....................... 116 4.7PrecisioninthemeasurementoftheARraysgeometry......... 117 4.8PictureoftheLDattheISR........................ 118 4.9SketchandpictureofaLaserBox..................... 119 4.10 Precision in the determination of the beam splitter position and orientation121 4.11PictureofaMABontheCMSdetector.................. 122 5.1ThemagnetcurrentduringthetwoperiodsoftheMagnetTest..... 126 5.2ThemagnetcurrentduringCRAFT08.................. 127 5.3TheCMScoordinateaxissystemandthedefinitionofangles...... 132 5.4 Illustration of the permanent and elastic motion cycles during phase I oftheMT.................................. 133 5.5 Illustration of the elastic motion cycles during phase II of the MT . 134 5.6 Relative distance between the first endcap disk and tracker as a function ofthemagneticfieldintensity....................... 135 5.7 Sketch of the deformation of the endcap iron disks with magnetic field . 136 5.8 Stability at 3.8 T of a sensor in measuring the distance between the AR andtheLD................................. 136 5.9 Illustration of the quasi–elastic motion of the detector at the end of phase I137 5.10 Measured distance between the LD and the AR as a function of B in thephaseIoftheMT........................... 140 List of Figures 5 5.11 Measured distance between the LD and the AR as a function of B in CRAFT08.................................. 140 5.12 Data points and fitted curves from the axial displacements between the TPandtheME1/1inCRAFT08positiveside.............. 142 5.13 Data points and fitted curves from the axial displacements between the TPandtheME1/1inCRAFT08negativeside.............. 142 5.14 Data points and fitted curves from the radial displacements between the TPandtheME1/2chamberinphaseIoftheMT............ 144 5.15 Data points and fitted curves from the radial displacements between the TPandtheME1/2chamberinphaseIIoftheMT........... 145 5.16 Data points and fitted curves from the radial displacements between the MABandtheME1/2chamberinCRAFT08+Zside.......... 148 5.17 Gaussian fit of a typical laser spot profile as measured in an ASPD . 153 5.18 The Z and R laser positions reconstructed by an ASPD for different valuesofthemagneticfield......................... 153 6.1 The disk YE+1, the wheel YB+2 and the AR w.r.t the CMS coordinate system.................................... 159 6.2 Local coordinate systems of ME1/1 and ME1/2 chambers in YE+1 and MABstructuresinYB+2......................... 159 6.3 Difference in position between photogrammetry and nominal values for variousalignmentstructures........................ 161 6.4 Difference in Rφ and in Z between the measured values by the ASPD sensors and the simulated value from the