1. Chamber Alignment Pins Δy = y PG – y nom. vs. Δx = x PG – x nom. M. Hohlmann 1, G. Baksay 1, S. Guragain 1, J. Bellinger 2, D. Carlsmith 2, F. Feyzi 2, R. J. Loveless 2, D. Northacker 2, V. Andreev 3, X. Yang 3, D. P. Eartly 4, O. Prokofiev 4, V. Sknar 5 1 Florida Inst. of Technology, Melbourne, FL, 2 U. of Wisconsin, Madison, WI, 3 U. of California, Los Angeles, CA, 4 Fermi National Accelerator Lab, Batavia, IL, 5 Petersburg Nuclear Physics Institute, St. Petersburg, Russia Compact Muon Solenoid Hardware Alignment System for Muon Endcaps Nucl. Sci. Symposium Oct 27 – Nov 3, 2007 Honolulu, Hawaii N15-257 Aligning the CMS Muon Endcap Detector with a System of Optical Sensors CCDs 4 CCDs 2 in 10 DCOPS Good hits ! Laser 2 Laser 5 Reconstruction of Muon Chamber z CMS - Positions Reconstruction vs. Photogrammetry Measurements Solid triangles: Reconstructed tops of CSC Alignment pins Solid triangles: Reconstructed tops of DCOPS boxes First CCD pixels Reconstructed positions of outer CSC PCB skins B=0T CCDs PG of TPs determines global z CMS position of entire system Open triangles: PG measurement of tops of DCOPS boxes Open triangles: PG meas. of CSC Alignment pins PG measurements of coded targets on outer CSC PCB skins Recon. & PG match well ! (no PG avail.) Precision Resolution Current Reconstruction Performance for axial z CMS - coordinate: Resolution & Sensitivity to relative motion: ~ 60 μm Precision of chamber position reconstruction: ~ 270 μm Accuracy from check against Photogrammetry: ~ 680 μm (Accuracy required by design: 1 mm) DCOPS CCDs Laser hits (shifted to the sides of CCDs for display) CCD2 CCD4 CCD2 CCD4 fitted position First CCD pixels Ref. CCD bad hits not used in fit Note: The lasers were tilted towards the chambers on purpose to compensate for disk bending at B=4T ! laser line fit Raw data: Laser profiles B=0T fit positions B=4T fitted CSC positions Disk bending is reconstructed ! This assumes that the TP’s do not shift in z & do not rotate! ~ 13mm B=4T M.H. fecit - Oct 2007 Conclusion: Accuracy of chamber installation on the disks in X,Y,Z is ~ 1 mm (rms) PG: Displacements from nominal positions Photogrammetry (PG) measurement uncertainties are  x PG =  y PG =  z PG = ± 0.3 mm Note: A systematic shift was subtracted for each chamber type:  Z = Z PG – Z Mean Chamber Coded Targets Δz = z PG - z nominal Discrepancy z PG – z reco (mm) 683 μm B=0T CSC & DCOPS Reconstruction Muon Endcap instrumented w/ Cathode Strip Chambers Muon Endcaps Yokes ME+1 ME+2 ME+3 ME+4 +z Muon Endcap stations: ME - 468 CSCs of 7 different types & sizes > 2,000,000 wires (50 µm Ø ) 6,000 m 2 sensitive area 1 kHz/cm 2 rates 2 mm and 4 ns resolution (L1 trigger) ~ 100  m resolution (offline) ME+2 Laser on Ref. DCOPS Chamber DCOPS’s Transfer Line DCOPS Z-tube Z-sensors Transfer Plate Clinometer Mounting Tower Back Chamber R-sensor Laser beam path 2 Crosshair Lasers (adjustable) Digital CCD-based Optical Position Sensor ME+2 Straight Line Monitor Cathode Strip Chambers Photogrammetry Targets CCD1 CCD2 CCD3 CCD4 DCOPS: 4 × 1-d CCDs 2048 CCD pixels 14 μm pixel pitch Chamber Alignment Pins Chamber Coded Targets DCOPS Target Analog Sensors: 84 Radial Chamber Position Monitors 84 Axial Disk Position Monitors 60 Clinometers for Transfer Plates R-sensors Z-sensors Note: only a small sample of analog sensors is shown Clinometers DCOPS Crosshair laser lines: Transfer lines Straight Line Monitors (SLMs) Laser Line System: 3 Optical Straight Line Monitors (SLMs) across each disk 2 Lasers & 10 CCD DCOPS’s in each SLM 6 DCOPS Transfer Lines connecting all ME disks ME+2 SLM2-5 Laser 5 Laser 2 Laser 5 Front Chamber ME+1 Station ME+2 Station ME+3 Station Coded Targets