Today

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 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 requried 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

I will calibrate the QPDs tomorrow. The OPLEV for the SR3 should be ready by tomorrow.