Took H1 to DC Readout for Kiwamu to run high power tests.  

• The Power Recycling gain has been running low (i.e. 33?).  Kiwamu wanted to adjust alignment to see if this could improve this gain.  

Toward the end of the shift, H1 could not lock the OMC.  Kiwamu traced this down to a rung up violin mode for ETMy.  I remember watching others damp violin modes, but I have not done it before.  I tried looking through wikis and alogs for instructions but could not find any.  

H1 taken to a DOWN state for the night.

Summary:

By looking at the XARM HWS signals, I can see that we're overestimating the response of the CO2 central heating. As a result, we are underapplying the preheating to stablize the total value.

Also: the H1:TCS-SIM_XARM_POWER estimate is now wrong following some recalibration work on the X_TR SUM signals the other day.

Details:

I looked at 24 hours of HWS and SIM data from two days ago. Aside from glitches, there were systematic discrepancies between the measured HWS signal (when scaled by 0.5 to convert it from double pass to single pass) and the sum of the CO2 and SELF heating SIM channels.

• SELF: I spoke to Kiwamu and he suggested that some whitening filter changes may be responsible for the change in calibration of X_TR_B_SUM (here?).
• CO2: it's clear by comparing the lenses measured by the HWS and predicted by the CO2 SIM in the period between 650 and 750 minutes that the CO2 lens is overestimated
  • A best fit between the SIM and HWS suggested that this needs to be dropped by a factor 0.573
  • So: 6.23E-5 diopters per Watt * 0.573 = 3.57E-5 diopters per Watt in H1:TCS-SIM_ITMX_SUB_DEFOCUS_CO2_GAIN

This means that the TCS Guardian function for calculating CO2 power will need to be adjusted. 

The attached plots show (a) the time series from the HWS, the CO2-SIM and SELF-SIM, (b) the HWS measurement minus the optimally scaled CO2-SIM measurement and (c) the second plot minus SELF-SIM calibrated to give the smallest RMS on the whole time series.

Keita, Kiwamu

We spent some time today trying to figure out what made the engagement of the ISS second loop so hard recently.
We conclude that the SR560, which has been served as a summing point for the second and third loop signals, is the one hindering the ISS second lopp. In order to for us to be able to lock with a low noise ETMY for the planned PI measurement, we bypassed the SR560. This means that the ISS first and second loops are in the same configuration as O1 and therefore no third loop is available.

If necessary, one can reconnect the SR560 and resurrect the third loop.

[Issues with SR560]
The SR560 caused two major issues. First, it limited the range of the auto reference adjuster to +/-3V. Second, when it saturates, the output of the SR560 sticks to a negative voltage value (-3 ish volts), regardless of which sign the input signal is. Therefore, when we request the engagement of the second loop, it tried to catch a linear signal within a smaller range. If fails, it can run into a region where the error signal has a wrong sign which drives the auto reference adjuster to the opposite direction. We think this is what has been going on with the second loop engagement in the past several days.

[A large offset]
Apart from the SR560, we found one thing which appeared to be an indication of a broken op-amp or some sort; the output from the second loop circuit board was measured to be -1 V, when the inputs were all disconnected. We thought this was another issue which had prevented the second loop to engage, but as we leaned later, this offset is not critical. By the way, this relatively large offset seems to be a function of the variable gain value. What is strange is that the offset becomes large when a smaller variable gain value is requested. We pulled the second loop servo box out of the rack and checked the behavior of the circuit in the EE shop. However, we could no find any failed op amp or anything. In the EE shop, since we did not supply an external signal to set the variable gain to a certain value, the gain value stayed to be 20 dB which, as mentioned, gave us a smaller output offset of -0.1V. We measured the transfer function of every active stage and confirmed that nothing was wrong. The circuit was then put back to the rack.
Although this issue (or perhaps feature) still remains, we are able to close the auto reference adjusting loop without the SR560. This means that probably this large offset is not the one preventing the second loop from engaging it. We may check the behavior of this variable gain stage at some point. 

TITLE:  5/20 EVE Shift:  23:00-07:00UTC (16:00-00:00PDT), all times posted in UTC     

STATE of H1:   Taken to DC Readout.  

Outgoing Operator:  TJ

Quick Summary:  

• Kiwamu at PSL racks.  Sheila investigating 3Hz noise at different power levels.  Ross, Tega, & Sheila are doing ETMy ESD/PI work.
• BRS is ACTIVE for EX/EY with 90mHz Quite Blend Sensor Correction with BRS.
• Environment:  decent with us recovered from earthquake of a few hours ago, low useism, and winds generally under 20mph.
• Observatory Mode is at PLANNED ENGINEERING

TITLE: 05/20 Day Shift: 15:00-23:00 UTC (08:00-16:00 PST), all times posted in UTC
STATE of H1: Planned Engineering
INCOMING OPERATOR: Corey
SHIFT SUMMARY: A few earthquakes prevented locking for a some hours, but Jim got some SEI testing in and commissioners are doing their thing now.
LOG:

• 16:37 - Richard to MY.
• 16:42 - Gerardo to LVEA to check on ion pump.
• 17:09 - Gerardo out.
• 19:40 - Sheila, Evan H, Hoacun to LVEA near HAM6.
• 19:52 - Keita, Kiwamu to LVEA PSL racks.
• 20:31 - Keita, Kiwamu out.
• 21:34 - Kiwamu to LVEA PSL racks.
• 22:10 - Gerardo to CP3.
• 22:11  -Sheila to LVEA PSL rack.
• 22:20 - Sheila out.
• 22:26 - Gerardo back.
• 22:46 - Kiwamu to LVEA.

Measurements done on IMs with damping loops turned off, and step functions put into the test alignment offsets in pitch and yaw.

Yaw shows yaw peaks.

Pitch shows pitch peaks, and yaw peaks when yaw is given a step function.

I could not locate historical Q measurements for pitch and yaw, only length, bounce, and roll.

For completeness, I've included resonant frequancy measurements from LHO and LLO.

(Chandra, Gerardo)

The annulus ion pump crashed early this morning, the plan is to replace it next Tuesday.

It appears that the pump was last replaced sometime in February of 2002.

1/2 open LLCV bypass valve, and the exhaust bypass valve fully open.
Flow was noted after 80 seconds, closed LLCV valve, and 3 minutes later the exhaust bypass valve was closed.

the h1psliss system was reporting a false difference in the filtermodules loaded vs the chans file. This was tracked to the rcg3.0 problem (reported https://alog.ligo-wa.caltech.edu/aLOG/index.php?callRep=27247) with repeating filters in the working file if a filter is loaded whose name is the core for other filters. In this case ISS_SECONDLOOP_REF_SIGNAL_SERVO was loaded which is the core name for ISS_SECONDLOOP_REF_SIGNAL_SERVOINF. After verifying that the diff being reported was solely due to multiple copies of the same filters, we performed a full filter load on h1psliss to clear the error. Since at all times the filters were being overwritten with identical filters, no runtime changes were made.

The ITMX and ITMY RH SIM SUB_DEFOCUS and SURF_DEFOCUS filters

• H1:TCS-SIM_ITMX_SUB_DEFOCUS_RH
• H1:TCS-SIM_ITMY_SUB_DEFOCUS_RH
• H1:TCS-SIM_ITMX_SURF_DEFOCUS_RH
• H1:TCS-SIM_ITMY_SURF_DEFOCUS_RH

were all reporting infinite/NaN outputs. I reset the histories on these to remove these NaNs.

We restarted the psinject CW hardware injections on h1hwinj1 last Wed 11th to see how stable this system is now. All was well until yesterday (Thu) when it stopped running for no discernable reason. Here is a summary:

We were not running under monit control so that a restart would be easy to spot. Now we have seen a restart, we'll put psinject back under monit control. Remember that the monit script smoothly ramps up the injection to prevent jarring.

Again, it looks like the drift down of the BRSY continues and the trend continues to ease albeit quite slowly.  The latest trend extrapolation still puts the 15000ct crossover around the 3rd of June:  The upper plot shows most of the BRSY life and the bottom I've zoomed in and eyeballed a line out to rebalance time.

SEI - Jim would like to start locked IFO to test some configurations.

Vac - Ion pump work at the diagonal.

Fac - Chiller showing up today for staging building.

These are the serial numbers for the in-service chillers:
P325-18636-1 S/N 44801 (crystal chiller)
P625-18637   S/N 44807 (diode chiller)

The old chillers had serial numbers:
P325-18636-1 S/N 44800
P625-18637   S/N 44806

When pulled from service the chillers had accumulated 30716 hours and
30790 hours respectively.  To my knowledge this cannot (as yet) be reset
from within TwinCAT, so the "new" chillers will have an artificially high
number of hours displayed.  To find the real number of operating hours,
one needs to interrogate the chiller control panel.

All 4 chillers have a date of manufacture of 07/2011.

TITLE: 05/20 Day Shift: 15:00-23:00 UTC (08:00-16:00 PST), all times posted in UTC
STATE of H1: Planned Engineering
OUTGOING OPERATOR: None
CURRENT ENVIRONMENT:
    Wind: 10mph Gusts, 4mph 5min avg
    Primary useism: 0.02 μm/s
    Secondary useism: 0.18 μm/s
QUICK SUMMARY: Unlocked, environment seems calm.

 

• Attempts made at Nominal Low Noise, but fell out at various points.  
• Restroed IMs to a pre-HAM2ISI WD trip & ran an Initial Alignment
• Kiwamu worked on high power investigations.
• 10:22 pm a GRB was acknowledged

Toward the beginning of the shift, the HAM2 ISI watchdog tripped (as well as all of the optics on this table).  After a few hours of locklosses, went ahead and checked/restored all Input Mirrors (IMs) to their OSEM values before the HAM2ISI WD trip (per instructions here).

Some of the mirrors required big slider moves for recovery. 

Have run an Initial Alignment on H1 and making attempts at locking.  Attached are trends of the IM OSEMs.

[Corey, Jenne, Kiwamu]

The DC Readout state checks whether the ISS first loop is on or not before allowing the IFO to increase power.  However, the state_word value for the ISS isn't matching what is in the guardian (it wants 32700), so it doesn't pass this check.  Both the integrator and the autolocker are on, which are the primary things that I thought were required.

Previously, the run state would check the ISS, and if it was okay, check ASC convergence, and then turn off the SRC1 loops.  However, since we're not passing the ISS check, I had Corey go to manual mode and request IncreasePower, which ended up skipping the SRC1 turn-off step. This caused our friend the SRM-runs-away lockloss.

So, we have modified the run state of DC readout a little bit so that the ISS and ASC convergence checks are separate if statements, not an if/elif combo.  If the ASC is converged, it will turn off the SRC1 loops, regardless of what the ISS is up to.  If both the ASC and ISS are happy, it'll return True like normal, and carry on.

Operators:  If you are stuck at DC Readout and the guardian log says "ASC converged" but you're getting the message that "ISS first loop may be off", then you should check on the ISS first loop*.  If it's okay, then go to manual, and select Increase power.  Go back to auto, and select whatever state you were trying to get to.

* I think that the only check for ISS first loop at this state that really needs to happen is that the "First Loop" light in the small blue box under the strip chart on the PSL_ISS screen is green (sorry Jim).  This indicates that the integrator is on.  If it's yellow, click the "On+Int" button on the ISS manual mode sub-screen.  Clicking the "On+Int" button to ensure it's on shouldn't cause any trouble, so you can do that if there's any ambiguity.

Sheila, Jenne, Evan

We have suspected for some time that the POPAIR B diode (which we use to extract POPAIR18 and POPAIR90 signals) is saturated in full lock, because these signals do not scale appropriately when increasing the PSL power. Now that we are seriously trying to use POPAIR90 to diagnose DRMI angular behavior during power up, we would instead like to use a signal that we can trust.

We tried a few different things today:

• Take the rf monitor for POP45 (in-vac) and feed it into the POPAIR90 demodulator. This seems to give a signal that scales appropriately with the PSL power (good), but the SNR is worse (bad).
• Take the rf monitor for POPAIR45 and feed it into the POPAIR90 demodulator. Same performance as above.
• Insert a 12 dB coupler directly into the POPAIR45 line. Feed the coupled output into the POPAIR90 demodulator. This gives a signal that scales appropriately with the PSL power and has comparable SNR to POPAIR90.

The last of these is the configuration that we have now. Whitening and dark offsets were set to give appropriate signal levels.

Careful examination will actually show that there appears to be a bit of saturation with this POPAIR45 signal as the power is increased. According to the POPAIR_A_LF channel, there is 83 mW (!) of dc power on this PD at 25 W. Probably we should be closing the POP beam diverter at this power, or else we need to swap some optics on the table.

Ideas for how to improve:

• Put the coupler on POP45 instead, since the POP PD has four times less light than POPAIR A. Requires rechecking the phasing of POP45 for MICH and SRCL in full lock. Has the advantage of giving us POP90 information even when the POP beam diverter is closed.
• Investigate whether POPAIR B can be made to give sensible signals. Perhaps we should modify it, just as we did in order to make REFLAIR B give sensible signals.