peter.king@LIGO.ORG - posted 05:27, Thursday 07 July 2016 - last comment - 05:32, Thursday 07 July 2016(28216)
ISS measurements
Attached are measurements of the ISS transfer function performed after a
minor alignment adjustment to the ISS AOM. These were taken with the gain
slider at 6 dB and 9 dB. The offset slider was left at 6.35.
With the gain slider at 6dB the UGF is about 54 kHz; 9 dB 70 kHz.
However there is considerable peaking in the noise spectrum. The free-running
noise is also attached.
All measurements were taken with PDA which was the in-the-loop sensor
at the time. The reference signal was at -2.00. At this setting the measured
DC output of PDA was -8.70 V.
Jason/Peter
Images attached to this report
Comments related to this report
After tweaking the alignment into the pre-modecleaner, the DC output of PDA was measured to be between -12.5 V and -12.7 V with the ISS off. The half waveplate in the ISS PD box was adjusted to bring this down to about -9 V unlocked.