Georg Gassner Robert Ruland, SLAC February, 2008

1. Georg Gassner Robert Ruland, SLACFebruary, 2008 Laser Tracker Test Facility at SLAC • Introduction • Rotary Table Calibration • Laser Tracker Investigation • ADM Tests • Conclusion 1

2. Introduction • Particle Physics experiments at SLAC require high accuracy positioning, e. g. 100 µm over a distance of 140 m or 25 µm in a 7 x 10 x 3 meter room • Realization -> Laser Tracker Measurements • Rotary calibration table (Kugler GmbH) providing an accuracy of better than 0.2 arcsec • Interferometer bench 2

3. Rotary Table • Renishaw Signum RESM angle encoder system • 1 arcsec graduation accuracy • 0.01 arcsec resolution 3

4. Calibration of the rotary table (1) • Rosette technique • calibrate precision polygon prisms • sum of the angles measured must result in 360 degrees • Moeller-Wedel electronic autocollimator (0.1arcsec accuracy, 0.05arcsec reproducibility) 4

5. Calibration of the rotary table (2) • Derived Technique • set the fixture with the mirrors in a way that mirror ‘a’ is in line with autocollimator ‘a’ • rotate the table together with the fixture until mirror ‘b’ is in line with autocollimator ‘b’ 5

6. Calibration of the rotary table (3) • Absolute value of an angle between two positions of the rotary table can be determined with ±0.2 arcsec std. 6

7. Laser Tracker Horizontal Angle Measurement System Investigation • Test Setup • mirror as a target for laser tracker • parallelism of the two rotation axes • axial displacement of the rotation axes Mirror Faro Laser Tracker Rotary table 7

8. Comparison SMR vs. SMM • Test of Mirror (SMM) and Retroreflector (SMR) • Only small deviations can be found 8

9. Calibration Results Two calibration runs with Faro Laser Tracker Xi Two calibration runs with Faro Laser Tracker Xi V2 9

10. Carriage Interferometer Dd Horizontal Bench Laser Tracker ADM Calibration on Interferometer Bench • Calibration of the scale factor of the ADM in the field. • Tests of the general performance and tests to detect malfunctions in the laboratory. 10

11. Calibration Results Calibration run with Faro Laser Tracker Xi Calibration runs with Faro Laser Tracker Xi V2 11

12. Conclusion • Rotary table - absolute angle accuracy < 0.2 arcsec • Rotary table to test any horizontal angle measurement instrument • Faro laser trackers angle measurement system deviations stable and correctible • With corrections, angle accuracies of 1 arcsec are possible. • Test of the ADM showed its usability as a replacement for the interferometer mode 12

13. End of Presentation 13