1. Status Brussels GANTRY Ê Try to assemble modules with good precision 4 different calibration plates (Karlsruhe and Bari) 4 determination of pin positions relative to markers on plate Ë Control methods for precision 4 compare measurements in Brussels and Aachen 4 compare measurements in 3 different positions of the plate Ì Plans for the near future Í Test to glue stiffeners is OK Î Very recent items : pin positions & cross-check measurements O.Bouhali, J.D’Hondt, C.Vandervelde, L.Van Lancker, J.Wickens Gantry meeting CMS – February 2004

2. Comparison of different calibration plates Ê Karlsruhe plate (measured in Karlsruhe) Ë Bari plate (measured in Bari and Dusseldorf) We have 2 calibration plates : We have 2 calibration plates : Bari the plate was only partially measured (500 of 625 points) At Dusseldorf we measured the complete Bari plate at the temperature equal to that in the GANTRY clean room (21.5 o C) The measurements were performed by a Mitutoyo high precision machine (resolution ~2  m) and with some pattern recognition Two measurements : fit with circle fit with cross no difference (~1-2  m)

3. Comparison of different calibration plates Y X operator Before calibration After calibration

4. Comparison of different calibration plates Karlsruhe on GANTRY Bari on GANTRY Y X operator

5. Comparison of different calibration plates Karlsruhe calibration defined as perfect Bari calibration Y X operator

6. Comparison of different calibration plates Karlsruhe calibration defined as perfect Dusseldorf calibration Y X operator

7. Comparison of different calibration plates Dusseldorf calibration defined as perfect Bari calibration Y X operator

8. Comparison of different calibration plates Y X operator Y axis X axis Y axis X axis Dusseldorf calibration defined as perfect Bari calibration

9. Comparison of different calibration plates  Y(Bari – Dusseldorf) Y X operator Line 1 Line 10 Line 20

10. Comparison of different calibration plates  Y(Bari – Dusseldorf) Y X operator Line 1 Line 10 Line 20

11. Comparison of different calibration plates  Y(Bari – Dusseldorf) Y X operator Column 1 Column 10 Column 25

12. Comparison of different calibration plates  X(Bari – Dusseldorf) Y X operator Line 1 Line 10 Line 20

13. Comparison of different calibration plates  X(Bari – Dusseldorf) Y X operator Column 1 Column 10 Column 25

14. Comparison of different calibration plates Ê Differences up to ~20 mm Ë For all the rest we will use the Dusseldorf calibration file Ì Pins have been re-measured Í Pin positions are determined relative to the fiducial markers on the plate Î Once determined they can be calculated everytime with a translation and rotation of the reference system (should be simple procedure) ++

15. Procedure to determine the pin positions ++ Pin positions are determined relative to the fiducial markers on the plate Ê Measure both fiducial markers on the plate Ë Take ~8 points around the circle of each pin hole Ì Fit a circle through them Í Repeat the above at least 10 times Î Look if the fits are stable (small residuals)

16. Fits to determine the pin positions

17. Comparison modules measured in Aachen and Brussels All can be explained by a rotation and a translation of the module between GANTRY position and Aachen position  measured shape of module is the same Assuming that the sensors didn’t move on the frame during transportation, we have to conclude that the pin positions are not the same in both cases ++ We assembled 3 real modules on our GANTRY and re-measured them in Aachen  Y( [measured – nominal] GANTRY – [measured – nominal] Aachen ) verified that nominal positions are identical !! Pos.1 Pos.2Pos.3 3230 44 4942 6055 1719 2322 2330 3437 2418 3741 3728 5457

18. Comparison modules measured in 3 different positions on the GANTRY ++ A dummy module has been measured in the 3 GANTRY positions  Y( [measured – nominal] Pos.X – [measured – nominal] Pos.X’ ) Pos.1Pos.2Pos.3 00 00 00 00 -14-9 -17-13 -20-8 -22-17 40 1011 812 1720 assuming position 1 is perfect : [meas – nom] = 0 All can be explained by a rotation and a translation of the module between GANTRY positions  measured shape of module is the same Same conclusion (transportation issue excluded), the pin positions used by the GANTRY are not the true ones… smaller residuals than one month ago

19. Conclusion and outlook for the future Ê Precision of modules is good according to GANTRY Ë Large disagreements with Aachen Ì Large disagreements in different positions (smaller than before) Í The problem can probably be allocated to the position of the pins Î Outlook : go back to the ‘old’ procedure of assembling modules Ï Revise the soft-ware which uses the calculated pin positions Some delay for R5 and R3 due to above problems Ê R5N : to be finalized (did some work on the pick-up tool) Ë R5S and R3 : soft-ware in development Ì R5 plates are ready and successfully tested for vacuum  R6.2 plate allows for a ~40-60  m glue layer

20. Recent items : pin positions Frame Pin Plate Procedure 1.We fitted the circle at the top of the pin and at the plate level 2.The center of both does not coincide 3.Hence pin not vertical 4.We assume that the pin is linear (straight) 5.Hence we can rescale the systematic shift to the frame level (~1mm)

21. Recent items : pin positions diff ~ 1diff ~ -5diff ~ -3 Difference between plate level and top of the pin level scaled to 1mm thickness real pin position shifted (in  m) in direction indicated 2.5 2.0 -0.3 3.7 0.9 1.6 -3.9 -7.0 2.8 4.6 3.6 5.5 Brussels-Aachen (3 dummy modules assembled in Brussels) Rotation ≡ 0 Translation ≡ 0 Rotation ~ -20 Translation ~ -14 Rotation ~ -10 Translation ~ -6

22. Recent items : pin positions If we should correct for the non-vertical feature of the pin, we would have a good agreement between Aachen and Brussels (no residual rotation) Still a translation between Aachen and Brussels of ~ 25-30  m News from yesterday  also this shift is gone due to a systematic mistake in Aachen Very preliminary conclusion : It could be that all discrepancies between Aachen and Brussels are understood !!! to be verified in detail !!!