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CMS Hardware-based Muon Alignment

CMS Hardware-based Muon Alignment. CERN – June 15-16, 2009. LHC Detector Alignment Workshop. Gervasio Gómez. for the CMS Collaboration. CMS Muon System. Y. Endcap Disks: C athode S trip C hambers ( CSC ). Return iron Y oke in red. X. Y oke E ndcap: YE. Z. Y oke B arrel: YB.

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CMS Hardware-based Muon Alignment

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  1. CMS Hardware-based Muon Alignment CERN – June 15-16, 2009 LHC Detector Alignment Workshop Gervasio Gómez for the CMS Collaboration

  2. CMS Muon System Y Endcap Disks: Cathode Strip Chambers (CSC) Return iron Yoke in red X Yoke Endcap: YE Z Yoke Barrel: YB Barrel wheels: Drift Tubes (DT) Resistive Plate Chambers (RPC) in both barrel and endcap LHC Detector Alignment Workshop, June 15-16, 2009

  3. CMS Muon System Muon Barrel (MB) stations Muon Endcap (ME) stations 4 DT stations in 5 barrel wheels and 12 phi-sectors: 250 DTs 4 CSC stations in 3+3 endcap disks and 16 phi-sectors: 540 CSCs LHC Detector Alignment Workshop, June 15-16, 2009

  4. CMS Muon Alignment System: Barrel • Alignment of 250 Drift Tubes w.r.t. each other • Redundant network of optical connections • MAB: Module for the Alignment of the Barrel • Rigid carbon fiber structure housing cameras • Some also contain Link components • LEDs mounted on DTs are read by • cameras mounted on MABs • Z-bars provide better z-resolution LHC Detector Alignment Workshop, June 15-16, 2009

  5. CMS Muon Alignment System: Endcap • Relative alignment Cathode Strip Chambers w.r.t. each other. • Network of optical connections complemented by • inclinometers and axial and radial distance meters. • Straight Line Monitors: • 3 per Muon Endcap station • Laser lines read by • Digital CCU Optical Position • Sensors (DCOPS) • Z-sensors • Relative z distance • between Muon Endcap • stations • Transfer lines • SLM across z, measure • relative x,y displacements • between ME stations LHC Detector Alignment Workshop, June 15-16, 2009

  6. CMS Muon Alignment System: Link AR LD MAB Alignment of DTs and CSCs in a common frame of reference related to the tracker. Network of optical connections complemented by inclinometers and axial and radial distance meters Lasers from Alignment Rings (AR) to Link Disks (LD) at Yoke Endcaps YE±1, deflected and read by Amorphous Silicon-strip Position Detectors (ASPD) mounted on Muon Endcap ME±1 chambers and on MABs on Yoke Barrel YB±2 LHC Detector Alignment Workshop, June 15-16, 2009

  7. CMS Muon Alignment System YB+2 YE+1 DCOPS LD AR Link line MAB ASPDs SLM LHC Detector Alignment Workshop, June 15-16, 2009

  8. CRAFT Alignment Results: DT Sector 7 Sector 8 • Full DT geometry reconstruction in progress • Processing ~7000 optical measurements • Recent milestones • Calibrated all 250 DTs • LED positions on DTs • Calibrated all 36 MABs • Camera positions inside MABs • Automated DQM: discard bad LEDs • Working offline geometry reconstruction model • Initial partial DT geometry reconstruction at 3.8 T • Only one active plane • Stability over 1 week at nominal field < 40 mm • Partial geometry reconstruction at 0T compared to Photogrammetry/Survey • MAB z,rf positions compatible at the sub-mm, 10-2 mrad level • DT positions compatible at the mm, 10-1 mrad level MAB LHC Detector Alignment Workshop, June 15-16, 2009

  9. CSC alignment strategy y’ CSC x’ • ME2,3,4 • Start with survey (0T) • Add relative shifts from 0T to 3.8T from Z-Sensor measurements Fit all ME±2,3,4 SLMs and reconstruct CSC positions: ZCMS and x’ • ME1 • Start with geometry reconstructed by Link system • Also use Z-sensor measurements Fit all SLMs and reconstruct CSC positions: ZCMS and x’ z’ = ZCMS LHC Detector Alignment Workshop, June 15-16, 2009

  10. Endcap Disk Bending at 3.8 T SLM1 SLM2 SLM3 B=3.8T LHC Detector Alignment Workshop, June 15-16, 2009

  11. CRAFT Alignment Results: Link Movement of structures under magnetic forces Only the +z side of the link system could be reconstructed during CRAFT ~DZ(YE+1,YB+2) Final closure of disk after large B-field is applied Elastic deformation of disk 21-Nov 25-Aug 3.8 T 0 T 21-Nov 25-Aug LHC Detector Alignment Workshop, June 15-16, 2009

  12. Disk movement from 0T to 3.8 T form Link • YE+1 Z displacement of 12.47 mm towards IP • ME1/2 chambers are left behind by 1-3mm • They are also tilted about 3.5 mrad YE+1 @ B=0T YE+1 @ B=3.8T Relative displacement in mm in absolute CMS coordinates. Relative orientation in local chamber axis in mrad ME1/2 ME1/1 12.47 mm LHC Detector Alignment Workshop, June 15-16, 2009

  13. 0T to 3.8 T: Link vs Endcap ME12 CSCs are reconstructed independently by link and endcap • Differences in position/orientation of ME+1/2 chambers between LINK COCOA fits at B=3.8T and B=0T • Corresponding ENDCAP numbers: Agreement: X, Y: ~30 mm Z: ~190 mm LHC Detector Alignment Workshop, June 15-16, 2009

  14. 0T vs 3.8 T: Link vs Barrel Compare Z-compression of Link-reconstructed MABs with Z-compression of DTs from partial DT reco • Link-reconstructed position/orientation of the 6 MAB’s in YB+2 wheel: 1.4 mm (-z side) 3_5 YB-2 1.7 mm 1.6 mm 3_3 3_7 Shortening at 3.8T wrt 0T from DT partial reco 3_1 1.8 mm 3_9 DZs agree to < 1 mm Average agreement ~340 mm 2.3 mm 3_11 2.7 mm LHC Detector Alignment Workshop, June 15-16, 2009

  15. Current CSC Hardware Aligment CMS Side view Nominal CSC position Not to scale B=3.8T   <x>: 1.3mrad    <x>: 1.3mrad  rglobal <x>: 2.4mrad <x>: 2.6mrad <x>: 2.7mrad <x>: 2.2mrad   zglobal <x>: 4.4mrad < x>: 4.4mrad       x= 0 <x>: 2.7mrad <x>: 2.2mrad <ΔzME+1/2>: -5.04 mm <ΔzME-1/2>: 5.94 mm <x>: 1.6mrad <x>: 2.5mrad <x>: 1.9mrad <x>: 1.6mrad   <ΔzME-2/1>: 10.23 mm <ΔzME-3/1>: 11.39 mm <ΔzME+3/1>: -4.31 mm <ΔzME-4/1>: 8.49 mm <ΔzME+4/1>: 0.65 mm <ΔzME+2/1>: -0.97 mm <ΔzME+1/1>: -17.57 mm <ΔzME-1/1>: 16.73 mm   nom. nom.       Pink: Aligned by Tracker-Muon Link system Blue: Updated ! Aligned by Muon Endcap optical & analog (Z sensors) System Red: No alignment yet   Nominal CSC position       <ΔzME+3/2>: 3.26 mm <ΔzME+2/2>: 6.74 mm <ΔzME-2/2>: 2.74 mm <ΔzME-3/2>: 3.86 mm <ΔzME+1/3>: -4.08 mm <ΔzME-1/3>: 4.08 mm ME+4 ← Muon Endcap stations → ME+3 ME+2 ME+1 ME-1 ME-2 ME-4 ME-3 LHC Detector Alignment Workshop, June 15-16, 2009

  16. Conclusions & Outlook • Achievements • Reconstruct movements/deformations due to magnetic forces • Independent system measurements show good agreement • First combined Link+Endcap geometry constants • For endcap Cathode Strip Chambers • Used for CRAFT reconstruction • Initial partial geometry reconstruction of barrel Drift Tubes • Outlook • Finish full DT geometry reconstruction • Produce combined hardware DT+CSC geometry • Relate it to tracker frame • Estimate alignment uncertainties • Include alignment+uncertainties into global track reconstruction • Combine with track-based • Take the best of each system LHC Detector Alignment Workshop, June 15-16, 2009

  17. BACKUP LHC Detector Alignment Workshop, June 15-16, 2009

  18. Offline Geometry Reconstruction COCOA: CMS Object-oriented Code for Optical Alignment Geometrical reconstruction based on iterative non-linear c2 fit Parameters can be fixed, calibrated or unknown Correct parameters iteratively Propagate errors taking into account correlations Measurements System Description Interconnection of elements Mechanical hierarchies Initial geometry (Photogrammetry or ideal) Best geometrical description compatible with measurements and calibrations Parameter errors and correlations LHC Detector Alignment Workshop, June 15-16, 2009

  19. BACKUP: Alignment Data Flow S2G19 PC PVSS RDB online (P5) offline CMSMON PC (CMS CR) Tier-0 + CASTOR T0 injection script ROOT /cms/mon/data/ cocoafiles.root ONLINE DB ORACLE CAF input COCOA output Kvaser POPCON application ORCON DTAlignmentRcd DTAlignmentErrorsRcd CSCAlignmentRcdCSC AlignmentErrorsRcd Validation ORCOFF DTAlignmentRcd DTAlignmentErrorsRcd CSCAlignmentRcdCSC AlignmentErrorsRcd CMS RECO LHC Detector Alignment Workshop, June 15-16, 2009

  20. BACKUP LHC Detector Alignment Workshop, June 15-16, 2009

  21. BACKUP LHC Detector Alignment Workshop, June 15-16, 2009

  22. AR w.r.t. TK Not drawn to scale! disk10+ disk10- disk9+ disk9- BD+ TK BD- AR+ AR- 0 2956 -2956 -2667,5 -2754,9 2754,9 2667,5 D = 87,4 LHC Detector Alignment Workshop, June 15-16, 2009

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