During the transition to my Day shift, I followed our usual check list for Maintenance days, which included taking SEI_CONF to SC_OFF_NOBRSXY. When Hugh and I went to recenter the STSs and T240, the SEI_ENV node was still looking for earthquakes and saw large ground motion, caused by Hugh and I. The node proceeded to switch to earthquake mode in the middle of our recentering. Many chambers tripped as a result.

The failure here was that I was following a checklist that I had not updated to reflect this new SEI_ENV node. This node should be taken to the MAINTENANCE state every Tuesday morning to avoid this in the future. I will update the checklist now, and double check others to make sure it doesn't need to be somewhere else that I can't think of.

Attached below are the results for the monthly charge measurements.

ETMX: No significant change observed, the effective bias voltage for the pitch is varying from 10-50V. Last month's measurement for the first quadrant had a huge error bar, which was not observed this time. For the Yaw, the first quadrant is sitting at 60V and the rest are between 30-40V.

ETMY: Increase in the bias voltage for the 2nd quadrant for the Pitch, which is at 85V, which is big jump from last month (57V, with a big error bar). There was a rising trend over here past few months. The other two quadrants are looking stable at 20-40V. For the Yaw, the bias voltage is stable at around 25-30V.

All the  slider values were restored after the measurement was complete and SDF differences were looked into.

[Sheila, Jenne]

Although the squeezer seems to not have gone into oscillation since last Thursday when we lowered the green power (alog 55339), we are looking to see if we can better understand the cause and ameliorate it (spoiler alert: so far we don't know, although we have further tests to try today). 

Here's what we've done so far:

• Noted that the OPO_PZT_1_VOLTS was 57.4V and had been drifting downward lately.  Recall that we don't tend to see oscillations unless the OPO locks with the PZT above 60V. 
• While on the phone with Sheila, I moved the green ISS setpoint (H1:SQZ-OPO_ISS_SETPOINT) to bring the OPO_TRANS_DC_NORMALIZED power up until we started to see oscillations. 
  • The oscillations started when the TRANS_DC was just shy of 1.7. 
  • This brought the SHG_LAUNCH_DC_POWERMON to about 17.7mW, which is under the threshold of 20mW (to prevent fiber degredation we prefer not to launch too much power in).
  • Interestingly, the OPO_REFL_DC_POWER was slowly increasing as I increased the green power, but then it jumped up a lot when the oscillations started.
  • In the first attachment (IncrPowerToStartOsc.png) you can see that the TransDC and ReflDC are increasing as I change the ISS setpoint, but around -4490sec the REFL power jumps up and we start oscillating.
• We turned off the green ISS using the Servo/Ramp button.  The oscillations were gone, but the power had gone down since we were no longer servoing to that ISS setpoint.  Turning the ISS back on brought the power back up and the oscillations back.
  • Turning off the ISS is shown at the very end of the first attachment, around -4455sec.
• I went out to the squeezer rack and changed which of the 2 PZTs that can be used to lock the OPO we were driving. 
  • We have access to both via the squeezer interface chassis in the squeezer rack's slot 12, but only one driver.
  • Sheila had brought the squeezer manager guardian to DOWN, and ensured that the PZT voltage out was near zero (~1V). Richard confirmed that it should be totally fine to switch the cables on the back of the interface chassis.
  • The driver had been plugged in to PZT1, and a terminator was on the PZT2 SHV connector. The second attachment (PZT_connectors_before_change.jpg) shows their configuration before my change.
  • I unplugged both the cable and the terminator, and put the terminator onto the PZT1 connector and the cable from the drivere onto the PZT2 connector. The third attachment (PZT_connectors_after_change.jpg) shows their configuration after my change.
• Sheila requested the squeezer manager to relock.  Using PZT2 (although the channels are still called PZT1) the OPO locked at around 26.5V.
  • The oscillations were really bad, although that was partly because the ISS was railed.  (The voltage limiter at the output of the ISS had a red box around it.)
  • We turned off the ISS and the oscillations went away. 
  • We returned the ISS setpoint to the value we'd been using that gave green power of 1.2, then reclosed the ISS and the oscillations were gone.
• We moved the ISS setpoint to re-increase the green power, and the oscillations showed up just shy of 1.6 (a little lower than when we were using the original PZT). 
  • This must have been very close to the threshold where the oscillations start, because they seemed to breathe, and then went away on their own.
    • In the fourth attachment (PZT2_oscGoAwayByThemselves.png), the oscillations start near the left side of the plot, and decay away by about -2540sec.
  • I increased the green power a small amount, and the oscillations came back. 
  • I decreased the green power and the oscillations went away, so this was definitely on the threshold of where the oscillations are happening.
    • The increase and decrease of power happened around -2500sec on the fourth attachment.
• Sheila changed the locking parameters for the squeezer guardian (the voltage at which it starts the scan for locking the OPO), and relocked the OPO at a higher PZT voltage.  It ended up being about 58.5V.
  • The oscillations were present.  I reduced the green power a small amount around -2385seconds in the fifth attachment (PZT2_higherVoltage.png).
    • The oscillations in the TransDC and ReflDC got a bit smaller, but the oscillations on the launch power completely went away.  This is new behavior.
• At this point, we are thinking about other tests, so we leave the PZT driver connected to PZT2 (we'll want to revert this at the end of our tests today).  The squeezer manager guardian is in DOWN.

All three dust monitor vacuum pumps are running well. 
The pump body temperatures range between 103f and 139f. 
Made a small tweak to the vacuum pump air bypass in the corner station. 
Observed no carbon dust on the filters. 

Closing FAMIS #13008

   HEPI pump fluid levels and pump stations checkout OK. No new leaks were noted. 

   Fluid Levels: 
CS - 6 5/16" - No change from last check
EY - 8 14/16" - No change from last check 
EX - 7 13/16" - No change from last check

   Closing FAMIS #13498

I reset both PSL power watchdogs at 17:57 UTC (9:57 PST), thereby completing FAMIS 10752.

In addition, I noticed that the ISS diffracted power % was on the low side (~1.2%, normally closer to 2%), so I adjusted the ISS RefSignal from -1.99V to -1.98V; the ISS is now diffracting ~1.7%.  The RefSignal change was accepted in both safe and observe SDF files.

FAMIS9532

2020-03-03 08:45:08.355362
There are 1 STS proof masses out of range ( > 2.0 [V] )!
STS B DOF X/U = -2.291 [V]

All other proof masses are within range ( < 2.0 [V] ):
STS A DOF X/U = -0.752 [V]
STS A DOF Y/V = -0.929 [V]
STS A DOF Z/W = -0.412 [V]
STS B DOF Y/V = -0.456 [V]
STS B DOF Z/W = -0.354 [V]
STS C DOF X/U = 0.42 [V]
STS C DOF Y/V = 0.846 [V]
STS C DOF Z/W = -0.161 [V]
STS EX DOF X/U = -0.057 [V]
STS EX DOF Y/V = 0.301 [V]
STS EX DOF Z/W = 0.226 [V]
STS EY DOF X/U = 0.524 [V]
STS EY DOF Y/V = -0.472 [V]
STS EY DOF Z/W = 0.735 [V]

There are 8 T240 proof masses out of range ( > 0.3 [V] )!
ETMX T240 2 DOF X/U = -1.296 [V]
ETMX T240 2 DOF Y/V = -1.309 [V]
ETMX T240 2 DOF Z/W = -0.865 [V]
ITMX T240 1 DOF X/U = -1.498 [V]
ITMX T240 3 DOF X/U = -1.545 [V]
ITMY T240 2 DOF Y/V = 0.305 [V]
ITMY T240 3 DOF X/U = -0.554 [V]
ITMY T240 3 DOF Z/W = -1.851 [V]

All other proof masses are within range ( < 0.3 [V] ):
ETMX T240 1 DOF X/U = -0.036 [V]
ETMX T240 1 DOF Y/V = -0.076 [V]
ETMX T240 1 DOF Z/W = -0.124 [V]
ETMX T240 3 DOF X/U = -0.112 [V]
ETMX T240 3 DOF Y/V = -0.135 [V]
ETMX T240 3 DOF Z/W = -0.092 [V]
ETMY T240 1 DOF X/U = -0.121 [V]
ETMY T240 1 DOF Y/V = 0.256 [V]
ETMY T240 1 DOF Z/W = -0.036 [V]
ETMY T240 2 DOF X/U = -0.053 [V]
ETMY T240 2 DOF Y/V = -0.076 [V]
ETMY T240 2 DOF Z/W = -0.085 [V]
ETMY T240 3 DOF X/U = -0.05 [V]
ETMY T240 3 DOF Y/V = -0.125 [V]
ETMY T240 3 DOF Z/W = 0.092 [V]
ITMX T240 1 DOF Y/V = 0.112 [V]
ITMX T240 1 DOF Z/W = 0.114 [V]
ITMX T240 2 DOF X/U = 0.09 [V]
ITMX T240 2 DOF Y/V = 0.173 [V]
ITMX T240 2 DOF Z/W = 0.165 [V]
ITMX T240 3 DOF Y/V = 0.061 [V]
ITMX T240 3 DOF Z/W = -0.047 [V]
ITMY T240 1 DOF X/U = 0.132 [V]
ITMY T240 1 DOF Y/V = 0.14 [V]
ITMY T240 1 DOF Z/W = 0.219 [V]
ITMY T240 2 DOF X/U = 0.093 [V]
ITMY T240 2 DOF Z/W = 0.211 [V]
ITMY T240 3 DOF Y/V = 0.182 [V]
BS T240 1 DOF X/U = -0.025 [V]
BS T240 1 DOF Y/V = -0.12 [V]
BS T240 1 DOF Z/W = 0.27 [V]
BS T240 2 DOF X/U = 0.077 [V]
BS T240 2 DOF Y/V = 0.242 [V]
BS T240 2 DOF Z/W = -0.027 [V]
BS T240 3 DOF X/U = 0.058 [V]
BS T240 3 DOF Y/V = -0.183 [V]
BS T240 3 DOF Z/W = -0.192 [V]

TITLE: 03/03 Day Shift: 16:00-00:00 UTC (08:00-16:00 PST), all times posted in UTC
STATE of H1: Observing at 118Mpc
OUTGOING OPERATOR: Patrick
CURRENT ENVIRONMENT:
    SEI_CONF state: WINDY
    Wind: 10mph Gusts, 8mph 5min avg
    Primary useism: 0.02 μm/s
    Secondary useism: 0.31 μm/s
QUICK SUMMARY: 89 hours locked. Maintenance about to start.

    Laser Status:
    Front End Power is 32.08W (should be around 30 W)
    70W Output Power is 69.49W
    Front End Watch is GREEN
    70W Watch is GREEN

    PMC:
    It has been locked 6 days, 20 hr 7 minutes (should be days/weeks)
    Reflected power = 11.83Watts
    Transmitted power = 51.9Watts
    PowerSum = 63.73Watts.

    FSS:
    It has been locked for 3 days 16 hr and 54 min (should be days/weeks)
    TPD[V] = 5.523V (min 0.9V)

    ISS:
    The diffracted power is around 2.5%
    Last saturation event was 3 days 16 hours and 52 minutes ago (should be days/weeks)

    Possible Issues:  No apparent issues at this time.

TITLE: 03/03 Eve Shift: 00:00-08:00 UTC (16:00-00:00 PST), all times posted in UTC
STATE of H1: Observing at 64Mpc
INCOMING OPERATOR: Patrick
SHIFT SUMMARY:

H1's been locked over 81hrs with range just under 120Mpc.  Microseism is inching up just a little.
LOG:

• (from DAY shift) Temporary calibration lines running around 500Hz & will be turned off within 2hrs. (Sudarshan)
  • 2:14 - 2:17 Out of Obseriving to turn off temporary Calibration lines. (Sudarshan)
• 2:02 TCS Chiller check (Corey)
• 2:36 GRB Short received & had stand down.

H1's been locked over 77.25hrs.  A few big glitches in the last 30min, but all looks good.

Addressed TCS Chillers (6:02pm local):

• TCSx Chiller:  Had level of 29.3 cm.  Added 100mL for 30.0cm.
• TCSy Chiller:  Had level of 10.0 cm.  No water added.

Looking again at H1:ASC-AS_A_RF36_Q_PIT_OFFSET and H1:ASC-AS_A_RF36_Q_YAW_OFFSET, while relocking H1, I've plotted 15 relocks, and instead of plotting pitch and yaw, I've plotted the sqrt(pit^2 +yaw^2), which represents the combined offset required for each relocking sequence that reached ISC_LOCK =110, where the offsets are set.

In the attached plots, I collected data at the interval of 120 seconds from LL (lockloss) to NLN (Nominal Low Noise).  Then I reduced the data further, but starting 120 seconds before the first time that the AS_A pitch and yaw offsets were set, and ending at NLN.  Any lock atempts that are before the first time that ISC_LOCK reached 110 are not shown, however every lock attempt from the first ISC_LOCK = 110 to NLN is included, so each plot shows continuous data along the X axis, every 120 seconds.

The legend is only on one plot (ugh), so I'm listing it here, and givning more detail, which applies for each of the 15 plots:

• H1:GRD-ISC_LOCK_STATE_N  -  green solid line
• H1:GRD-INIT_ALIGN_STATE_N  -  black solid line, data is multiplied by 5, to make the trace easy to see
• H1:ASC-AS_A_RF36_Q_PIT_SWSTAT  -  black line with astrics, data is divided and shifted by some value to fit plot
• H1:ASC-AS_A_RF36_Q_YAW_SWSTAT  -  magenta line with astrics, data is divided and shifted by some value to fit plot
• sqrt(PIT_OFFSET^2 + YAW_OFFSET^2)  -  black solid squares, with vertical black lines
  • the black solid square is the last data point before the offsets are set to zero
• NLN  -  magenta uward pointing solid triangle, with vertical magenta lines
  • the magenta triangle is the first data point where ISC_LOCK is at or above 557.  The need to select data points that are less than ISC_LOCK  = 600 is an artifact of sampling every 120 seconds
  • Each NLN was verified by subtracting the START times (GPS start times) for each data point.  During relocking the data points are 120 seconds apart, and when H1 reaches NLN and stays in Observing, the difference between the START vlaues is greater than 120 seconds.

In the title of each plot is the NLN number, 1-15, the START time (GPS start time), and a comment about the offsets (black squares), and if they were increasing or decreasing, or the SWSTAT remainded in the "offset ON" for multiple relocking attempts.  I didn't collect the OUTPUT AS_A pitch and yaw data for this data set, but have for other data sets, so the SWSTAT is included here just to give a sense of how often it changes, and how often it stays in the ON position.

There are some interesting changes in the offset values, and in particular the change in plot NLN 11, bottom left corner, with a change from before x = 60 to after that is clearly visible, but there is no change to INIT_ALIGN.  I could imagine that a manual alignment of one or possibly a few optics is the soure of the change, but I haven't looked into it, so at this point the explanation is unknown.

Even though this data is from a month ago, it has an interesting feature, which is that each row of plots has it's own set of offset values that relocked and made it to NLN:

• the top row: all relocking offset values are at 700 or above
• the middle row: all relocking offset vaues are between 530 and 670
• the bottom row: all relocking offset vaues are below 545, and as low as 140

Charting the max, min, and mean values:

This suggests some change that might be possible to track down, and I found this data with no particulare goal in selecting the number of relocks, or when in time, other than within the last 2 months, so it's very possible that all of the data for relocking would have this feature, which could reflect changes that happen on the scale of days to weeks.

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. 

TITLE: 03/03 Eve Shift: 00:00-08:00 UTC (16:00-00:00 PST), all times posted in UTC
STATE of H1: Observing at 117Mpc
OUTGOING OPERATOR: Jim
CURRENT ENVIRONMENT:
    SEI_CONF state: WINDY
    Wind: 15mph Gusts, 12mph 5min avg
    Primary useism: 0.04 μm/s
    Secondary useism: 0.35 μm/s

Microseism is slowly increasing over last 24hrs (but still under 90th percentile).  Winds are hovering just under 20mph (after recently being above 20mph for an hour-ish).
QUICK SUMMARY:

H1's been locked almost 73.5hrs (observing only 2+hrs due to today's calibration work) with a range hovering just under 120Mpc.

Sudarshan currently has some calibration lines running around 500Hz, and will be turning them off in about 90-120mins.

TITLE: 03/03 Day Shift: 16:00-00:00 UTC (08:00-16:00 PST), all times posted in UTC
STATE of H1: Observing at 113Mpc
INCOMING OPERATOR: Corey
SHIFT SUMMARY:
LOG:
19:00 JeffK running calibration measurements

20:41 Back to Observing

22:08 JeffK & Sudarshan changing PCAL lines

22:14 Back to Observing

J. Kissel, S. Karki

Sudarshan / Dripta have analyzed the data from the last test of PCALX vs. PCALY from back in early February (LHO aLOG 54873), and found that -- even with the factor of ~8 increase in SNR they gained from moving the usual 1153 Hz pair of lines down to 530 Hz -- the variation in the data over the 4 hour test was too large to determine the calibration discrepancy between the ends to a satisfactory precision. 

Thus, today, we try again, with the PCAL lines back down at 530 Hz, but with an increase in amplitude by a factor of 3 (and a flip-flip of frequency assignment).

These lines will be in the data for ~4 hours, and have been installed in the observation ready segment starting at Mar 02 2020 22:13:35 UTC (1267222433).
PCALX has been placed at 530.20 Hz, with amplitude 3.0*5007.0 = 15021.0 ct_pk.
PCALY has been placed at 530.10 Hz, with amplitude 3.0*3619.0 = 10857.0 ct_pk.

With these excitation amplitudes -- and the other "normal" PCALY calibration lines running at 17.1, 410.3, and 1083.7 as well as pulsar injections -- the RMS excitation value is 16021.6 ct_RMS for PCALX and 9189.13 ct_RMS for PCALY. The RMS for PCALX when high frequency roaming line is at 3001.3 Hz, is 21507 ct_RMS, so theoretically there is more head room to increase the amplitude more, if need be, but at the time we don't find it necessary, and we do quite enjoy this kind of head room we have before saturation.


Attached are screenshots of the SDF differences that were accepted to make this temporary change, and an ASD and RMS of the total requested excitation signal coming out of each PCAL. 
Note -- in order to obtain this increase, we had to completely turn OFF the high frequency roaming PCALX line (which is currently at 3001.3 Hz -- but given that we've had a beautiful 70+ hour lock stretch, we won't miss these 4 hours).

In the comments to this aLOG are a number or supporting figures for the suspension model changes for LHO calibration.