1. 1 Status of Forward Pixel Survey Andrei Gritsan, Mikhail Kubantsev, Nhan Tran* TB Meeting 16/04/08

2. 2 Concept/Formalism Each surveyed hierarchy consists of a system of points By use of rigid body formalism, we can determine how much each object is rotated and translated. We overlay survey and reference (fiducial) systems to determine ΔR and ΔΩ i = 1…N is the number of substructures per hiearchy j = 1…n is the number of points per substructure r ij is the position of each point; m ij is the mass of each point dr ij is the difference between reference and surveyed systems

3. 3 Recap of Forward Pixel Survey Panel Survey Half Disk Survey Half Cylinder Survey Survey Hiearchy: Module Panel Half Disk (one-side) Half Disk Half Cylinder Pixel Endcap Software Hiearchy: Module Panel Blade Half Disk Half Cylinder Pixel Endcap

4. 4 Half Disk Level Survey Using CMM measurements of fiducial points on modules, find displacements of: Modules on a Panel Panels on a Half Disk (one-side) Used stainless steel balls as reference targets to join two sides of a Half Disk “Finger-printing” of panels on half disk using known displacements of modules on a panel to find misidentified panels

5. 5 Half Disk Error Analysis Errors at each hierarchy propagated by measurement uncertainties Using Toy MC analysis, we propagate measurement uncertainties into displacement uncertainties Module uncertainty is dominated by time/installation Panel/Blade uncertainty dependent on the number of point surveyed Panel Toy MC Study Survey errors used by alignment group

6. 6 Results of Forward Pixel Half Disk Level Survey RMS values for module, panel, and blade local displacements Values considered as placement uncertainty Given in local frame; rotations given in Euler angles u (μm)v (μm)w (μm)  (mrad)  (mrad)  (mrad) Module60.346.714.30.411.342.08 Panel46.340.954.53.843.662.03 Blade71.471.771.53.563.832.63

7. 7 Recap of Forward Pixel Survey Surveyed Panel, Blade, Half Disk hierarchies via CMM measurements at FNAL Survey of about 200 production panels with CMMmeasurements Survey complete of all 8 FPix Half Disks Error analysis at all hierarchy levels http://indico.cern.ch/conferenceDisplay.py?confId=17330

8. 8 Half Cylinder Survey To create a half cylinder system, three sets of measurements used 1.Half Disk CMM measurements of sensor fiducials and 1mm phototargets for each side at FNAL 2.Half Disk PHG measurements of 1mm and 3mm phototargets at FNAL 3.Half Cylinder PHG measurements of visible 1mm and 3mm phototargets with half disks inserted at CERN In joining measurements (1) and (2), usually are about 30 common targets (next slide) In joining measurements (2) and (3), common targets vary between half disks (next slide)

9. 9 Half Cylinder Survey Common targets in creation of Half Disk System Common targets in creation of Half Cylinder System

10. 10 Half Cylinder Survey Results Results for each half disk in the half cylinder Values are presented about a point defined as the sum of the positions of the daughter modules of each half disk in the CMS global frame

11. 11 Forward Pixel Survey Object A comparison of FPix Survey with Ideal Geometry All Survey measurements for each hierarchy are compiled and applied to the CMS geometry Results are saved to DB A typical plot: Δr/Δz/rΔ  vs. r/z/ 