Hugh, Sheila

We noticed that the OMC suspension sliders aren't calibrated, so we did a quick check by moving 100 slider counts in pitch and yaw and looking at the DAMP IN.  We found we got 21 urad of pitch for 100 counts and 9 urad/100 counts in yaw.  So the OMC suspension calibration should be 4.76 counts/urad for pit, and 11.1 urad/count for yaw.  

I updated the slider gains and the current offsets.  

ITMX pitch is close to -10 urads

Turbo pumps left valved-in (in parallel) while IPs stabilize.

RGA text file attached with scans before-during-after valving in last two NEG pumps in corner station (NEGs within several feet of RGA). Gerardo will note the times that he valved in each pump in order to correspond to RGA scans. We were looking for changes in H2 partial pressure but didn't see much change by simply eye-balling the RGA scan; attached is PDF of scan after pumps valved in - H2 partial pressure was at ~ 1e-7 A before and after.

11/25, 5:00 UTC

After L1
lens swap

IM1 and IM2 changed to
center on IM4 TRANS

IM1 and IM2 restored to
historical values

1) Changes of 0.23 to 0.32 on IM4 TRANS QPD are large, and will be seen in the IFO
2) The IMC beam spot measurement script (setting P2L and Y2L gains) is being run today if/when the IFO breaks lock
           a) this will tell me how much the beam changed at IM1, a change that is then propagated through the IO system and into the IFO

Laser Status:
Front End Power is 33.37W (should be around 30 W)
70W Output Power is 71.17W
Front End Watch is GREEN
70W Watch is GREEN

PMC:
It has been locked 0 days, 13 hr 53 minutes (should be days/weeks)
Reflected power = 10.78Watts
Transmitted power = 54.36Watts
PowerSum = 65.15Watts.

FSS:
It has been locked for 0 days 1 hr and 1 min (should be days/weeks)
TPD[V] = 4.115V (min 0.9V)

   Chillers are running well. Both filters are clean and clear. Both chiller water levels were good; did not add any water to either. No additional leaks from the valve that was worked on last week. 

   Closing FAMIS #8315

J. Kissel

Given the recent success at recovering the interferometer (e.g. LHO aLOGs 45632, 45629), and the pending engineering run, I'm gearing up to craft DTT templates for measuring the DARM loop and its sensing function that are more likely to provide better uncertainty in calibration parameters. One of the sticking points between L1 and H1 calibration analysis in O2 was the difference in frequency vectors over which we'd measured.

As such, I've compared the frequency vectors of latest sensing function measurements between sites. There're some good qualities from each site that we should both do:
(1) L1 has frequency points that directly line up with their calibration lines.
(2) H1 has more densely packed points below 10 Hz in order to better inform the MCMC algorithms that determine the fit SRC detuning spring frequency (f_s) and Q (Q_s) for the reference model.
(3) H1 measures out to 1.2 kHz
(4) L1 has more densely packed frequency points around the cavity pole.
(5) H1's measurement takes 4 minutes for PCAL, and 25 minutes for DARMOLG, for a total of less that a 1/2 hour.

I'll be working on a frequency vector that satisfies all of these good features over the next few days as we measure H1. As soon as I'm happy I'll recommend the same vector to L1.

-Dec 10th VAC work will not close GV’s

-PSL lower periscope mount swap set for Dec 11th

Tuesday Maintenance

-HAM1 pressure good, HAM6 pressure a little high, can transition both to ion pump

-Pcal model update

-SUS MC1, MC3M model update (early morning)

-BSC ISI model update (early morning)

-TCS model update (early morning)

-HAM1 illuminator, camera, WFS cabling

-LASER SAFE for removing scaffolding, leak checking

-Potential DOLPHIN fiber swap

TVo, Dan, Stefan

With the new alignments to get PRG~47.7 at 20W we tried to increase to 30W. The ASC became unstable pretty quick, plot attached, and eventually we lost lock. Briefly had 85 Mpc.

TVo, Dan, Stefan

When I came in, the IFO was lock (by itself?) in low-noise, but quite a bit of low frequency noise. That noise was due to a bad A2L and a bad SRCL decoupling, presumably due to the bad SOFT and PRC1 loop position.

- First we ran an A2L, which indeed fixed the low frequency ASC noise. But we will have to redo that with good RG.

- Next we tuned the SOFT and PRC1 loop positions at 2W, to see where we can get with the recycling gain in that state. We recovered a RG of 48.1 at 2W. 
- That's a slightly lower than the before the vent and TCS pre-loading (we had around RG=50). But note that if the pre-loading adds extra arm-scatter-loss, then it is most likely due to the CO2 heating. (The ring heater lens is very clean.) But the CO2 heating will be backed off anyway at high power.
- Offsets at 2W:
   DSOFT  P  +0.03  Y  -0.02
   CSOFT  P  +0.02  Y  +0.07
   POP_A  P  -0.65  Y  -0.15

- So we went to 20W with these offsets. Initially the RG dropped to 41.6. But through careful tuning we got it back up to 47.7. The attached plot shows our offset-walk.
- Offsets at 20W:
   DSOFT  P  +0.19  Y  -0.32
   CSOFT  P  +0.03  Y  +0.03
   POP_A  P  -0.52  Y  -0.03

- On top of the SOFT and and PRC1 offsets (i.e. the pointing loops), we also noticed that PRC2 liked some small offsets:
    H1:ASC-PRC2_P_OFFSET +20
    H1:ASC-PRC2_Y_OFFSET -30
  (We also checked MICH OFFSETS, but that didn't make a difference. We haven't checked INP1 and the SCL loops.)

Front end systems look good this morning. The only item to note is that h1sush56 detected Dolphin IPC errors from h1lsc0 and h1sush34 early this morning. These errors then propagated down the chain to the IOP models of h1seih16 and h1sieh45. The attached images show the IPC status for h1susomc, h1sussrm, h1sussr3 (on h1sush56), h1iopseih16 and h1iopseih45. The IPC overview medm is also shown.

All the events happened at GPS 1227774329 which is Dec 02 2018 00:25:11 PST

Danny, Craig, Dan Brown

We had a long lock run in low noise tonight. During this we were adjusting the PRC1 offset resulting in some slight alignment drifts of the BS and ITMs (45623). You can see the affect this has on the HWS spherical power here. The alignment offsets started around -3000 seconds on the time axis, first in pitch and then in yaw.

This drift was enough to see how the self heating spot moves relative to the HWS probe beam: ITMY before and after. The red cross is where the IFO beam was before the vent. The other thing to notice is that by choosing the reference time for when the point absorbers have heated up we can get the wavefront distortion without them included, so we see the broader absorption. We also ramped the CO2 heater to get a position of the CO2 relative to the interferometer beam, which is noticeably offset.

We did the same alignment shift images for ITMX, before and after. For ITMX the self heating spot wasn't in a bad position to begin with, however with the new offsets it's become misaligned to the HWS probe beam, so we need to do some picoing.

Lastly, we ramped CO2Y up and down to find the position on HWSY but also to see how the PRC gain and noise was affects. Turning the CO2Y power up 2X resulted in the ASC becoming unstable and noise increased at low frequencies, PRC gain didn't really change. Turning it down 1/2X did the same, DHARD yaw became unstable and we lost lock. We did notice a high frequency bump appearing at several kHz, similar to the frequency noise bump when changing the CO2 laser significantly. More investigation needed on that though. When HWSX is sorted out again we'll run some better comm and diff CO2 tuning.

Danny, Craig, Dan Brown

Here's a chronological list of observations and things we did today after the Dolphin crash to try and get the interferometer back up and locking.

• We reset all the watchdogs and set all the alignment sliders to before the crash, most needed adjusting. After putting everything back the alignment still wasn't great.
• We did initial alignment again but Y wouldn't level off. It hovered around 1 for awhile when setting the arm to INITIAL_ALIGNMENT, but it would keep periodically dipping to 0.8 then back up to 1 every 4-5 seconds.
• It turns out the FIR filters H1:ISI-ITMY_ST1_SENSCOR_GND_STS_X_FIR_GAIN, H1:ISI-ITMY_ST1_SENSCOR_GND_STS_Y_FIR_GAIN, H1:ISI-ITMY_ST1_SENSCOR_GND_STS_Z_FIR_GAIN were all 0. Looking at ITMX they were all set to 1 so we changed them manually. Seemed to fix the ALS Y alignment dipping problems we had.
• FIND_IR: TRY_NORM was registering high even with no light, so we ran userapps/isc/h1/scripts/dark_offsets/dark_offsets.py. However, the script set it to a negative offset so we did it by hand.
• We were still struggling to find IR. We adjusted comm offset to find it ourselves. Although this was an issue with the first few locks it seemed to be fine later in the day.
• We were losing lock at OFFLOAD_DRMI_ASC, so we increased the ramp from 2s to 20s to not kick it so hard. Didn't have any issues with this state for the rest of the day.
• During ENGAGE_REFL_POP_WFS, PRC1 and INP1 pitch ASC were railing causing us to lose lock. We switched on INP1 manually and stepped PRM pitch until the PRC1 error signal was closer to zero, letting PRC2 and INP1 follow. During this time PRG drop from 47 to 42, engaging CHARD dropped us to 40 and got very noisy so we may be clipping now. This all turned out badly in the end. When CSOFT_P gain was increased it became unstable and we lost lock. We think this means our input alignment isn't great right now. At this stage we also lost FSS lock?
• We changed these offsets to stop PRC1 wandering off and keep us at PRG~47:
  • H1:ASC-POP_A_PIT_OFFSET from -0.08 to -0.713
  • H1:ASC-POP_A_YAW_OFFSET from -0.24 to -0.08
• We lost lock at increase power. FSS also unlocked again.
• Stayed at decrease 45 modulation for awhile and we lost lock again, FSS also railed again. A 21Hz instability was ringing up in OMC DCPD output. It looks like it was coming from DHARD pitch from the lockloss tool.
• H1:PSL-POWER_SCALE_OFFSET for some reason got set to 1.3 instead of 1.8 on lockloss. This led us to believe our RF18 and RF90 were significantly higher.
• Eventually we reached nominal low noise at 20W.