1. A.Ostaptchouk AMS Meeting at CERN, 16 July 2002 1 Measurements of Octagon Walls with 3D CMM Characteristics of 3D CMM Measurement program Results of insert measurements diameters distances planarity straightness Conclusions & Plans

2. A.Ostaptchouk AMS Meeting at CERN, 16 July 2002 2 Characteristics of 3D CMM 3D Coordinate Measuring Machine Type Wenzel RS-1618 Range 2500  1600  1800 mm 3 Precision 20 + (L/50 mm)  m  70  m Sensitive elements mechanical feeler or video camera

3. A.Ostaptchouk AMS Meeting at CERN, 16 July 2002 3 Mounting Inserts of Octagon Wall Seven inserts on the top flange Five inserts on the bottom flange Specification on insert diameter: 15.0± 0 0.020 mm

4. A.Ostaptchouk AMS Meeting at CERN, 16 July 2002 4 Position of Wall on CMM Table Kinematic 3-point support

5. A.Ostaptchouk AMS Meeting at CERN, 16 July 2002 5 Position of Wall on CMM Table

6. A.Ostaptchouk AMS Meeting at CERN, 16 July 2002 6 Insert Measurements Measurement of circumference Measurement of plane surface

7. A.Ostaptchouk AMS Meeting at CERN, 16 July 2002 7 Results (1) Insert Diameters

8. A.Ostaptchouk AMS Meeting at CERN, 16 July 2002 8 Results (2) Insert Distances All distances are within ±50  m from specs RMS value: 28  m

9. A.Ostaptchouk AMS Meeting at CERN, 16 July 2002 9 Results (3) Inserts Planarity All residuals are within ±30  m interval RMS value: 9  m

10. A.Ostaptchouk AMS Meeting at CERN, 16 July 2002 10 Results (4) Inserts Straightness All residuals are within ±50  m interval RMS value: 19  m

11. A.Ostaptchouk AMS Meeting at CERN, 16 July 2002 11 Conclusions & Plans   Octagon wall measurements with Aachen 3D CMM show that their mounting inserts have the following characteristics -20  m  Diameter – 15mm  0  m -50  m  Distance - nominal  50  m -30  m  Residual planarity  30  m -50  m  Residual straightness  50  m which is well within specs   This allows to start assembly of the TRD octagon   Global survey of the assembled octagon (including measurements of the positions of module slots) will be performed immediately after assembly completion