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

A.Ostaptchouk AMS Meeting at CERN, 16 July 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

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

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

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

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

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

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

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

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

A.Ostaptchouk AMS Meeting at CERN, 16 July 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