DCPD2 got misaligned during the cable installation. The PD alignment procedure have been gone through again.
- Removed the FC layers for the cavity related mirrors.
- Aligned and locked the cavity.
- Loosen DCPD2. Checked the reflection with a IR card. Checked the spot on the PD with an IR viewer.
- Finger-tight the screws. Check the reflection with the card again. Check the pot on the PD with a CCD.
- If the spot positions are not satisfactory repeat the process.
- If the spot positions are satisfactory, take pictures of the CCD image.
- Fixing screws for all of the PDs/QPDs were tighten by the torque driver with a torque od 1.75 inch lb.
PD QE measurements
- Measure the power incident on the PDs.
- Set up the transimpedance amp to check the photo current.
- PD1 (T side) 9.10+/-0.03 V 13.02 +/- 0.01W -> QE ~80%
- PD2 (R side) 8.70+/-0.01 V 12.53 +/- 0.01W -> QE ~80%
- These are not strange values considering the presence of the glass caps.
PZT polarity check
- The connections between the PZT electrodes and the pins were checked.
- The positive side is marked by a knot on the wire.
- The new FC bottle was brought from Downs, thanks to Margot.