Original report: 7751 (SR2), 7748 (SR3)
On 2019-01-22:
For SR2:
I swapped the lens which has a 150 mm focal length inside the lens holder with the 300 mm one.
I measured varies distances that are required for obtaining the OL2EUL matrix.
The details are listed below:
- Viewport to steering mirror: 290 mm
- steering mirror to TILT QPD: 175 mm
- Steering mirror to BS: 50 mm
- BS to lens: 40 mm
- So we need the legnth sensing QPD to be 384 mm behind the lens.
- lens to folding mirror: 105 mm
- folding mirror to length QPD: 279 mm
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For SR3:
The light source of the SR3 was borrowed by SR2 so I placed the new light source on the SR3 OPLEV breadboard at the transmit side.
I replaced the 3500 mm focuser with a 1.1 m collimator.
The beam was realigned so that the reflected beam has minimal displacement in the T direction and is as close to the center of the TM as it could get.
I measured varies distances that are required for obtaining the OL2EUL matrix.
- viewport to steering mirror (where the beam spot is): 300 mm
- steering mirror to tile QPD: 160 mm
- steering mirror to BS: 50 mm
- BS to lens: 50 mm
- So the length sensing QPD should be put at 382.5 mm behind the lens with 300 mm focal length
- lens to folding mirror: 115 mm
- folding mirror to LEN QPD: 267.5 mm