The IR path on ISCEX must have gotten misalinged, I tuned up the beat note and now we have -13.5dBm reported by the PFD.
Running from opsws0. Should finish by the morning meeting. It's very windy right now, so we may not get anything useful out.
- Ref Cav not locking in the morning around 8:30 AM. Sheila D was notified and now locking stably - Transition LVEA to laser hazard at 8:45 AM PT - Richard M looking at ELIGO TCS viewports on the X Arm spool. - Jeff B and Andres R working on SR3 - Dave and Jim doing a DAQ restart at 11:01 AM PT - Arnaud at HAM4 working on SR2 at 1:28 PM PT - Bottled water refill on site at 9:30 AM PT
I misaligned the BS and ITMX and looked at the trended time series of REFLAIR_A_RF45_Q_ERR. Since the beam is (in theory) bouncing prompty off the PRM and onto the diode without any kind of Fabry-Perot interference, this signal should tell us something about 45 MHz RFAM.
The calibration (7.6 cts / nm) is from elog 10127.
As Kiwamu pointed out, the calibration must be multiplied by R_PRM / T_PRM^2, since the PD experiences the reflection of PRM rather than the doubly-transmitted beam. The plot is now corrected.
We used AM laser to check up the ALSX WFS.
AM laser output: 1.8mW (measured with old ophir power meter, 978nm, filterr out)
Modulation source was set to 0.1vpp 24.389310MHz (this frequency was set before fixing the 1.002MHz that was mentioned in another alog).
WFS DC interface was set to low DC gain mode and the DC offset zero-ed.
Demod whitening gain was 21dB, first and the second whitening filter were on and the third off, a-whites were turned on though I don't know if they're put in yet (turns out that the awhites were not yet there when we did this measurement, so the "demod" numbers in the table below are 33dB higher than they should be.).
| WFSA DC | WFSA demod (both I and Q) | WFSB DC | WFSB demod (both I and Q) | |
| SEG1 | 3000 cts | +-20k cts | 2600 | +-19k |
| SEG2 | 3070 | +-20k | 2900 | +-9k |
| SEG3 | 2395 | +-12k | 2740 | +-20k |
| SEG4 | 2930 | +-18k | 2960 | +-20k |
Seems like the demod signal out of WFSA SEG3 and WFSB SEG2 are both about a factor of 2 smaller than the others. On the scope it seemed that the RF signal coming from the WFS head was already small for these segments.
We confirmed that the whitening gain and filters are working.
Jax found that depending on how the cables were strained on the AM laser the amplitude of AM varies greatly (from nothingness to full). Crappy RF connection?
I didn't see such an effect when I used it at ISCT1 a month ago and the AM power was reproducable. This could be a new issue.
There may have been a miscommunication between me and Keita. When the cables were strained, they applied a torque to the laser, twisting it out of alignment with the WFS aperture (maybe 45 degrees rather than head-on? didn't exactly measure it, just corrected it.) So the power level issues were caused by cable strain, but on a purely mechanical level.
We have found that the polarization of PDH/WFS path was totally bogus because of one HWP somebody has installed, and that was the reason why the green 50:50 S-pol splitter was giving us something like 20:80. We rotated the HWP such that 50:50 becomes 50:50-ish, but that also means that 80:20 splitter to separate PDH and WFS was also affected.
Before: 4.4mW or so going into PDH, 4.8mW into WFS (0.9mW WFSA and the rest WFSB).
After: 8.2mW for PDH, 1.2mW for WFS (0.6mW WFSA, 0.6mW WFSB).
Tomorrow we'll remove the HWP as it is not in the design.
During green WFS RF check we've found that the PDH modulation frequency was set to 23.387319MHz , which is 1.002MHz off of our previously set frequency 24.389319 MHz (see alog 9708 when it was set last time). Strange.
Added APPSROOT environment variable to the default user environment with a value of either /ligo/apps/linux-x86_64 or /ligo/apps/darwin-x86_64 as appropriate. Also fixed MANPATH environment variable value so it also points to system man pages.
Here is the list of commissioning task for the next 7-14 days:
Green team:
Red team:
Blue team (ALS WFS):
Blue team (ISCTEY, delayed):
TMS:
SEI/SUS team:
This morning, with a little help from Hugh, I finished preparing the ISI for chamberside check out. I replaced the bad St1H3 cps, fixed some cable routing issues, then floated and balanced the stages. All went relatively painless, aside from the chaotic, cramped quarters in the end station (cables EVERYWHERE!). Now, all the sensors seem functional and I've started running some basic tests. Should be starting on tf's soon.
Working on unlocking SR2 suspension.
Andres and I are done. We unlocked the suspension, which seems to be free when looking at the L to L TF.
The default nds server is now h1nds1 for new applications that use it. It had been moved to h1nds0 temporarily to allow maintenance on h1fw1.
Jim and Dave
Jim removed the unneeded second 16bit DAC card from the h1lsc0 IO Chassis this morning, starting at 10:21. I made the appropriate model change to h1ioplsc0.mdl (userapps SVN r7165).
This closes WP4446
I swtiched the stage one blends on ETMX back to Tcrappy, Attached is a screen shot of the opLevs, in units of urad, the green references are from before (stage 1 level 3, 250mHz blends, stage 2 level2 Tcrappy). The red is now, with Tcrappy on both stages.
With the 250s, the Pitch rms is 0.7urad with the 250s, with tcrappy it is 0.5urad rms. (At the same times, the ITM rms is ust under 0.3 urad)
This is saved as sheila.dwyer/ALS/HIFOX/ISIs/TcrappyFeb18.xml
Filiburto replaced the DC power supply in h1susauxh56's IO Chassis. We restarted the front end and all looks good with this system.
I was in a hurry; Jim was at the end station and sorely needed my assistance. Anyway, despite several attempts, I was unable to transition either ITM to lower blends with the trilliums. Oddly, the BS went fairly easily...