TITLE: 03/12 Day Shift: 15:00-23:00 UTC (08:00-16:00 PST), all times posted in UTC
STATE of H1: Observing at 117Mpc
OUTGOING OPERATOR: Camilla
CURRENT ENVIRONMENT:
    SEI_CONF state: WINDY
    Wind: 6mph Gusts, 4mph 5min avg
    Primary useism: 0.02 μm/s
    Secondary useism: 0.22 μm/s
QUICK SUMMARY: Locked for 15 hours, calm environment. SEI_ENV recently transitioned back from the earthquake state after automatically taking us there for an EQ from Tonga area.

TITLE: 03/12 Eve Shift: 23:00-07:00 UTC (16:00-00:00 PST), all times posted in UTC
STATE of H1: Observing at 116Mpc
INCOMING OPERATOR: Camilla
SHIFT SUMMARY: Windy at the beginning of the shift, but it calmed down
LOG:

23:37 Observing

The short version: There have been some Resonance locklosses recently with simultaneous BS ISI Stage 2 trips, I think the ISI trips are a symptom, not a cause. We could avoid the trips by possibly moving the BS Stage 2 loops later in locking, or it might be possible to adjust SRCL to make it more stable. It would help diagnosing this if we could collect a SRCL open loop measurement while pausing at Resonance the next time we lock.

The blah blah blah: Over the last week or so there have been roughly 4 locklosses at Resonance that have had simultaneous trips of the BS ISI Stage 2. I have looked at a couple of these locklosses and it looks like SRCL might be going unstable, causing the locklosses. Because SRCL and MICH are coupled, this is causing trouble for the BS ISI. According to the lockloss page there have been about a dozen total locklosses at Resonance since Nov 1 of last year. Many of them are associated with BS M2 and SRM M3 drives ringing up.

First attached plot shows the LSC lockloss ndscope for one of the locklosses recently where the BS ISI ST2 tripped. MICH and SRCL see something ring up at ~82 hz before the lockloss.

The second attached plots are the drives for the BS ST2 for the most recent lockloss/trip, but every case I've looked at so far looks pretty similar, due to the SUS BS drive pushing on the ISI BS Stage 2. I've also seen locklosses where this same ring up happens in MICH and SRCL, but the BS Stage 2 doesn't trip. At this point I don't think the ISI is causing the locklosses, the trips are just a symptom of a particular kind of lockloss.

Sheila has suggested that optical gains are changing rapidly at this point, and was ready to believe that maybe something in SRCL in particular might be the culprit. When we get a chance, during the next re-lock she suggested we try measuring the open loop gain with the DTT template here: /opt/rtcds/userapps/release/lsc/h1/templates/SRCL/SRCL/SRCL_OLG_NOISE_FULL_LOCK.xml

Another solution would be to push turning the BS Stage 2 loops on later in the process. The third attached plot shows the BS ISI Stage2 V2 drives for 2 ISI trip/locklosses and 1 successful lock acquisition. For each subplot, the blue trace is the V2 drive, the red trace is the ISC_LOCK state *10. For each lock, after DRMI asc comes on the SUS BS is pushing pretty hard on the ISI Stage 2, increasing the V2 drive in response. At Resonance (where the red trace on the upper 2 plots show a lock loss), each lock shows the ISI drive increasing a bit more, ringing up and causing a trip for the top two plots. The bottom plot was a successful lock, and after Resonance the BS Stage2 drives calm down a lot. If we could wait until after DRMI on POP to turn on the Stage 2 loops, we would run much less risk of tripping the BS ISI. There were some foggy recollections of trying this in the past and it was too disruptive to turn on the loops later, but no one was very sure if that was true.

TITLE: 03/11 Day Shift: 15:00-23:00 UTC (08:00-16:00 PST), all times posted in UTC
STATE of H1: Aligning
INCOMING OPERATOR: Jim
SHIFT SUMMARY: Strong winds have hampered some of our commissioning and relocking efforts. Since the most recent lock loss we have lost lock from DARM_TO DC_READOUT three times. I just finished an initial alignment and Jim will be starting to try locking gain.
LOG:

• 1544 Lock loss
• 1550 Jeff B to LVEA to find storage cans
• 1550 Tyler to EY to find tooling
• 1557 Jeff B out
• 1558 Tyler heading back
• 1627 Cheryl to LVEA to look in cabinet
• 1631 Robert to EY during reacquisition
• 1632 Cheryl out
• 1708 Karen to MY
• 1709 Kyle to MX
• 1725 Robert done at EY
• 1728 Observing
• 1751 Lock loss
• 1811 Karen done
• 1831 Karen to MY
• 1841 Observing
• 1913 Robert to EY
• 1920 Commissioning
• 2028 Gerardo to MX
• 2030 Lock loss
• 2042 Gerardo back from MX
• 2235 Starting initial alignment

The wind is picking up to ~45mph gusts, and it's coming from a direction that the wind fences don't cover.

We have since been having trouble getting past DC_READOUT.

We have been running the DHARD P loop with a series of 5 resonant gains for historical and idiosyncratic reasons.  We had previously designed and tested a 1Hz boost with a bit of resonant gain to replace this a year ago, but we didn't keep this also for historical and idiosyncratic reasons.  

The attachment shows the comparison of the old resonant gain filter and the new boost.  The second attachment is a comparison of the ASC error and control signals before and after the change, things seem fine.  Our first lock with the new configuration was short, Camilla looked at the lockloss and said there were some of the fast glitches in DARM shortly before we lost lock.  

Since we still have not had a lon lock with this configuration, here are instructions for reverting it if we don't stay locked overnight:

• open ISC lock, uncomment line 3543 (switch in FM7), comment out line 3544 (switch on FM2)  uncomment line 4190
• These instructions are also in comments in ISC_LOCK.  

We had a total of 23 minutes in Observing before we lost it again.

Since SEI_ENV is now the manager of SEI_CONF (alog55296), I made it a bit bigger on the ISI_CONFIG.adl screen.

Reminder to operators: On Tuesdays, make sure to take SEI_ENV to the MAINTENANCE state, otherwise it may jump to earthquake and turn on sensor correction during maintenance times. The MAINTENANCE state will turn off sensor correction so we won't have worry about it during that time.

Went from 49% to 30%. it seems that ALSX polarization is moving with the outside Temperature, and it seems to be moving much more than Y. In the first attached plot the X polarization (blue) matches up with the outside temp (red). Second plot is just the polarizations for the past ~6 days.

No obvious cause

TITLE: 03/11 Day Shift: 15:00-23:00 UTC (08:00-16:00 PST), all times posted in UTC
STATE of H1: Observing at 116Mpc
OUTGOING OPERATOR: Camilla
CURRENT ENVIRONMENT:
    SEI_CONF state: WINDY
    Wind: 3mph Gusts, 1mph 5min avg
    Primary useism: 0.02 μm/s
    Secondary useism: 0.23 μm/s
QUICK SUMMARY: Locked for 15 hours, calm environment.

TITLE: 03/11 Eve Shift: 23:00-07:00 UTC (16:00-00:00 PST), all times posted in UTC
STATE of H1: Observing at 116Mpc
INCOMING OPERATOR: Camilla
SHIFT SUMMARY: One canadian earthquake, not much else to report
LOG:

23:50 Observing 

1:21 Verbal notification for a nearby earthquake, but it wasn't too rough on site

TITLE: 03/11 Eve Shift: 23:00-07:00 UTC (16:00-00:00 PST), all times posted in UTC
STATE of H1: Observing at 119Mpc
INCOMING OPERATOR: Jim
SHIFT SUMMARY: Maintenance day. Not a tough recovery, but one lock loss before shift end.
LOG:

• 1439 Out of Observing to start a measurement
• 1440 Tyler starting Kobelco pump
• 1457 Karen starting to drive to EY
• 1500 Scott taking forklift to from OSB receiving to staging building
• 1500 Kyle to EX
• 1504 Vanessa to LVEA
• 1505 Richard to MX MY new WAPs
• 1505 Dave restarting PSLFSS model and DAQ restart
• 1512 Robert to EX and EY, making it laser hazard
• 1524 Betsy to LVEA to find 3IFO HWS
• 1534 Richard back
• 1537 Hugh to LVEA looking at HAMs and 3IFO
• 1553 Fil, Richard to LVEA to cable measurements
• 1608 Jenne to LVEA to flip a switch
• 1610 Vanessa to EX
• 1612 Jenne out
• 1621 Dick and Marc to LVEA at ISC racks
• 1624 Jenne back in to flip the switch back
• 1631 Norco at gate, heading to tank 75
• 1631 Bubba to LVEA with contractors
• 1649 Chandra to LVEA to check on HAM8 crew
• 1707 Sensor correction back on in CS to get DRMI
• 1712 Chandra out, heading to EX
• 1720 Robert into LVEA to transition the East Bay to laser hazard
• 1720 Tyler out
• 1724 Tyler to EX
• 1735 Robert, Cheryl, Jenne to LVEA
• 1745 Betsy to LVEA
• 1803 Cheryl transitioning the LVEA to laser hazard
• 1803 Chandra to LVEA
• 1832 Chris done
• 1837 Chris to LVEA to unplug fork lift
• 1838 Gerardo to Ends to take pictures
• 1853 Hugh out
• 1854 Chris out
• 1900 Dick and Marc out
• 1900 Robert out and heading to EY
• 1910 Richard, Cheryl, Patrick, out
• 1936  Vac crew leaving EY
• 2056 Robert leaving EY
• 2057 Observing
• 2201 Lock loss
• 2210 Chandra, Camilla to EX to turn off turbo pump
• 2230 Chandra, Camilla back

I added two new features to the lock-loss-alerting system today.

Guardian repeat alerts

Guardian alerts are now handled the same way as lock-loss and out-of-observation alerts. The user has the option for a single alert (default time is immediate) or single alert plus repeat alerts (see attachment).

GraceDb event time

The time of the GraceDb event is shown both as its GPS time and a more readable time string like '50 minutes ago' or '5 hours ago' (see attachment)

(Filiberto C, Carlos P, Gerardo M)

The cable run was done last week as well as the termination of end connectors.  Today comunication was established with the rga at the Y mid station.

Sheila, Sudarshan

Since sensing function measurements taken during O3A, at low frequencies, couldnot be entirely explained by the detuned signal recycling cavity, efforts were made to understand the mechanism by which the measured sensing function could be explained. There were indications that some of these effect could be a result of unmodeled cross couplings between length and angle. Details of some previous efforts can be found in LHO alog # 50511 and DCC document G1901353.

Here we have explored the deviation in measured sensing function from the simple DARM model (with a cavity pole and optical gain) in two different configurations, with A2L gain turned on and A2L gain turned off. The details about the measurment can be found in LHO alog # 54679.

The sensing function model that is considered here is shown in the block-diagram below:

This model considers length (DARM) to angle coupling through the wavefront sensor of the DHARD loops. In this model, the sensing function depends on the the DHARD loop shape  as well as the A2L gain. The resultant sensing function differs from the simple model (without cross couplings) as follows:

C_new = C_old/[1-B(L2l*A2L/A2theta+m)]

where B is:

B = GDH/(1-GDH)*(L2WFS/WFS)

and GDH is the DHARD open loop gain.

The comparison between the model and the measurement is shown in the first attached pdf. It shows a reasonable agreement between the model and measurement, although there is some discrepancies at frequencies below 10 Hz. This model only includes the length to angle coupling in pitch. Coupling in yaw, we believe it to be relatively small, has not been considered. Additionally, the model of the DAHRD loop that is considered here doesnot completely agree with the measurement as shown in the second attachment.