We calibrated OMCR DCPD using Pcal integrating sphere. Numbers are to follow. (But note that Koji is worried that maybe the cover glass for that PD was cracked when they punched a vent hole on the diode case.)
We fixed the beam dump that was too high.
After that, we investigated the DCPD signal ground (alog 65081) and we think we know the cause of the problem but we don't have an easy fix. We'll leave it as is.
It seems that one of the cables (either PZT or QPD) that goes to the OMC breadboard was touching the OMC shroud panel. We'll revisit that in the morning, adjust that, then confirm that the laser is still hitting the OMC QPDs. If not we'll realign.
It seems that we have ground loop problem (PZT shield is connected to the chamber). We'll revisit that at some time, maybe in the morning, or maybe after we're done with the injection from HAM7 to HAM6.
This is a belated followup of OMCR DCPD calibration. Following channels were calibrated.
gain=1, FM4/5/6/9 always ON.
FM7/8 should be the inverse of H1:OMC-REFL_A_DC_GAINSETTING (e.g. enable "-20dB" if the gain is 20dB).
If you set the whitening gain to anything other than 0dB, use FM10 to define an appropriate compensation gain.
I made the following changes for H1:OMC-REFL_A_LF filters, and coefficients were loaded to H1OMC.
FM4 ("cts2V"), supposed to be 40/(2**16)
gain(0.00061035)
(doesn't matter much)
FM6 ("W/A"), supposed to be 1/responsivity.
FM9 ("inv(99:1)"), new filter, supposed to be
the inverse of the transmissivity of 99:1
gain(104.17)
Following is a table of parameters for Beckhoff:
Some details: