Long Wire Measurement System Georg Gassner, SLAC July, 2007

1. Long Wire Measurement System Georg Gassner, SLACJuly, 2007 • Introduction • Principle • Long Wire 1

2. Long Wire Measurement System • Purpose • Connecting different parts of a network together (in x - direction) 2

3. Long Wire Measurement System • Principle • Positioning of a platform relative to a wire at different locations • Connecting the network with the wire -> Laser tracker • Realization • Positioning capabilities • x- y translation -> one laser position in x and y each • Pitch, roll and yaw -> second laser position in x and y each plus bubble level for roll 3

4. Scan of Wire Along the X- Axis Scan of a 0.4mm diameter green monofilament wire (blackened) • Problem found here: ambient light influences reading -> measurements on Both sides of the wire 4

5. Scan of Wire Along the X- Axis Scan of a 0.8 mm fishing line (pink) 5

6. Long Wire Problem with long wire is the exposure of the wire to airflow, this results in vibration of the wire (Experiment in the gallery with a 250m wire resulted in vibrations with an amplitude of > 100 micrometers) -> Solution is to surround the wire with plastic sheets 6

7. Kink in the wire (1) To determine the existence of kinks in the wire two parallel wires were stretched over a distance of 80 m 7

8. Kink in the wire (2) To determine the existence of kinks in the wire two parallel wires were stretched over a distance of 80 m. In the ideal case this would result in a straight line. 8

9. Electro static charge No measurable deflection of the wire by charging the plastic cover Charged Plexiglas rod, 20 mm from line-> 20 micrometers Effect of plastic sheets expected to be 25-100 times smaller Precaution steps: Increasing the humidity -> spraying water on plastic 9

10. End of Presentation 10