Georgia, Sheila

Filter cavity green sensing beam

The filter cavity green sensing (FCGS) fiber on SQZT0 was misalinged because the AOM is now working.  We started the day by aligning that.  We measured 1.9mW into the fiber, and 0.56mW at the output of that first fiber. At the 50/50 beam splitter at the output of the fiber in chamber (H:BS1) we measured 195uW in transmission and 213uW in reflection.The pump and green feedthroughs were swapped 60148 on Oct 5th, but we didn't do a transmission measurement at the time which was an oversight.  In the following summary table of fiber transmission measurements, I am putting direct measurements in bold and the other numbers are infered from those measurements.   They key point here is that the transmission of the long in air fiber + in vac fiber for the OPO pump is very low, and low compared to what we would have expected after the swap. 

We found that the beam dump B:BD1 which catches the reflection from the OFI scatter monitor PD was in the way of the filter cavity reflected beam, so we moved it a few mm further from the PD (Georgia has a photo).  We had to move a cable clamp and a VOPO dog because this area is crowded.

We also checked the location of the three green beams (photo)  We confirmed that the filter cavity reflected beam is the middle of these three beams shown hitting the curtain.  Georgia touched up the alignment of the SK path interference. 

Picos

We attempted to start testing the picos, but found weren't able to use the pico driver for HAM7.  Patrick checked that all the beckhoff modules were OP, Filiberto came to the floor and identified that one of the Beckhoff cables (25 pin Dsub) was bent in a way that it might not have been making connections.  Filiberto fixed this, but we still couldn't communicate with the driver.  We swapped the cables so that we attempted to use the SQZT0 pico beckhoff cables to communicate with the HAM7 pico driver, but still couldn't communicate with it; we concluded that the chassis must not be working.  This chassis had no serial number or the usual red sticker; Filiberto took it to the shop and we swapped in a spare driver.  We the spare driver chassis and the HAM7 pico beckhoff cables, we still didn't see the driver responding to our requests, but we were able to get the driver working by connecting it to the SQZT0 pico beckhoff cables.  For now the SQZT0 pico driver is back to normal, and the new spare driver is installed where the HAM7 driver goes but the beckhoff cables are disconnected.

QPD

Georgia placed the adjustable dog clamp on the QPD that we have (photo).  The upside down bolt used isn't vented, which we need to double check.  Georgia also pointed the beam at the QPD.