Alexa, Keita, Evan
Alexa and I performed our usual loss measurement: Pon = 1257(5) ct, Poff = 1304(2) ct, giving a loss of 140(16) ppm in the Y arm.
Next, we wanted to assess the amount of scatter in the arms by looking at the amount of IR light on the baffle PDs. With the arm locked to IR and the IR WFS running, we misaligned the green light and looked at the ITM/ETM baffle PDs, both with their 40 dB and 60 dB gain settings. Then we removed the IR from the arm by unlocking the modecleaner and misaligning PR2. This allows us to get the dark counts on the baffle PDs.
Relevant times are as follows, all on 2015-01-09 UTC:
We're still working on analyzing the data.
For now, here is a dtt of our measurements showing the gain settings, the IR transmission, and the power of the baffle PDs.
BPD powers are given in the following table. Dark powers have been subtracted. The data are taken from the BAFFLEPD_#_POWER channels, which already contain calibration from counts to milliwatts. Plots, data, and code attached.