Jonathan, Satya, Jim, TJ, Dave:

This morning we installed the new x509 certificate on h1fescript0 to replace the expired cert. We were then able to restart the ext_alert code on h1fescript0. This runs under monit  management.

I have created an external alert overview medm screen, it is called from the SITEMAP via the SYS->'GRB/SN External Alert' pull-down. I pulled out the ext_alert parts from the CAL overview screen to make the screen (screenshot attached).

TJ verified that the audible alarms at the operator station are announcing these alerts.

Updated Virgo logbook links at top of page per FRS# 6465.

Measurements of the pre-modecleaner high voltage monitor with the pre-modecleaner locked and
unlocked (see plot legend).

Per FAMIS #6868, ran & checked ISI CPS signals for the BSCs & HAMs.  On both measurements (attached), no high frequency noise was observed.

Lost lock 3 times briefly after reaching NLN. Possibly ASC related. No PI modes seen ringing up on striptool. Decided to try an initial alignment and have not been able to get past ENGAGE_DRMI_ASC since.
At different times both H1:LSC-TR_X_QPD_B_SUM_OFFSET and H1:LSC-TR_Y_QPD_B_SUM_OFFSET got bad values that hindered finding and fine tuning IR.

07:18 UTC Terra turning on ETMY ring heater for PI test later today (Thursday)
09:15 UTC NLN
09:18 UTC Lock loss. EY saturated and ASC signals (mostly DHARD pitch?) started ringing up before lock loss.
10:02 UTC NLN
10:06 UTC Lock loss. Again ASC signals started ringing up before lock loss.
10:48 UTC NLN
10:52 UTC Lock loss. Again ASC signals started ringing up before lock loss.
10:56 UTC Starting initial alignment.
11:56 UTC Initial alignment done. Kept losing IMC lock. Had to redo input align. SRC also had trouble locking.
12:22 UTC Despite initial alignment had to check MICH fringes and lock on PRMI. Locking on PRMI took moving PRM around. PRMI to DRMI transition worked, but lost lock before DRMI_LOCK state.
12:36 UTC Stopped at DRMI_ASC. Signals fell and loss lock again.
Happened again. Stopping at LOCK_DRMI_1F. Seems stable here. Definitely ASC.
13:54 UTC Still can't get past DRMI_ASC. Starting another initial alignment.
14:09 UTC Peter to LVEA to take dark noise measurements and needs PMC unlocked. Stopping initial alignment after INPUT_ALIGN_OFFLOADED and set ISC_LOCK to DOWN.
14:57 UTC Peter done

Unless otherwise noted all powers measured with the water-cooled 300 W Ophir power meter.  The ISS was
unlocked but still diffracting light, whilst this does distort the beam it should be constant over the
time scale of the measurements taken.

    Using the locking photodiode over a 5 minute observation time:
  locked: -260 mV to -262 mV
  unlocked: -1.001 V to -1.004 V
Calculated visibility using the locking photodiode is thus: (74.0 +/- 0.4)%

    Using the power meter:
  locked: 30.5 W to 30.6 W
  unlocked: 121.6 W to 122.2 W
Calculated visibility using the power meter is (74.9 +/- 0.3)%

    The power transmitted by the pre-modecleaner was 105.7 W to 106.1 W.  Which suggests a pre-modecleaner
cavity transmission of (86.9 +/- 0.2)%.

    The errors listed above are okay to the precision of the measurement and not its accuracy.
Bearing in mind that the accuracy of the power meter is +/- 3%, the visibility measurement and
transmission measurement are on the edge of agreement.

    Taking accuracy into consideration the visibility is then (75 +/- 4)% and the transmission is
(87 +/- 5)%.  The two measurements are in general agreement but are not very accurate nor precise.

Turning the ETMY ring heater on 0 --> 0.55 W top, 0 --> 0.55 W bottom at 7:25 UTC. 

This is to revert alog 29702, bringing us back to a stronger optical mode overlap with the 47kHz ETMY mechanical mode so we can test the effectiveness of ESD damping at 50 W. 

TITLE: 10/19 Eve Shift: 23:00-07:00 UTC (16:00-00:00 PST), all times posted in UTC
STATE of H1: Commissioning
INCOMING OPERATOR: Patrick
SHIFT SUMMARY: Struggled to lock a few times but eventually made it to NLN. Noise hunting continues on the commissioning side.

Sheila Kiwamu Jenne Daniel

We measured the OLG of the PMC loop with the interferometer unlocked, and saw that it is aroun 500Hz while it is supposed to be at around 5kHz.  Plotting the measured OLG as closed loop supression, we predict that this loop should have gain peaking approximately around the frequency of our lump in DARM.  (second attachment).  We tried increaseing and decreasing the gain by 6dB, and didn't see much of a change in DARM.  

However, a driven measurement using the newly amplified HV mon as a readback predicts that this noise is about a factor of 2 below DARM in our lump.  The third and fourth attachments are the same noise injections that Jenne and I posted on monday for MICH SRCL and PZT jitter, with projections based on PMC PZT HV mon.  Kiwamu found an alog from april, 26538 indicating that the gain should be set to 30 dB (it has been 16 dB for the last several months).  The third attachment shows the noise projection with the PMC gain at 16dB, while the 4th one shows 30dB.  The 5th screenshot shows the difference in the DARM spectrum with the increased gain.  

People are still invesitgating the coupling mechanism, we think that intensity noise (which we think was the explanation for the simliar noise at LLO in  2014 16186) is ruled out by the intensity noise injection, although it is interesting to note that the spectrum of this PMC HV lines up fairly well with the ISS control signal.  

Last night the water level was at 7.7cm so I didn't add any water. Today I went out and it fell to 6.9 cm. That's less than 1 cm! Will continue to keep an eye on it.

1. Noise

When DBB HPO shutter was closed, DARM noise decreased. I did open/close/open/close and this was quite repeatable (first attachment, red/green are shutter closed, blue/brown are open). Some of the jitter-ish peaks subsided and the DARM looked much smoother when the shutter was closed.

These days DBB shutter is open most of the time (it seems to have been in local mode most of the time for jitter FF). Now we're in half-working remote mode where the MEDM screen says "local" all the time but we can close/open the shutter by pressing buttons.

This should be some kind of scattering problem, e.g. optical feedback into HPO and/or even to the frontend.

Inside DBB the reflection from DBBPMC is received by photo diodes, there's one transmission received by CCD camera but the DBBPMC was not resonant. There's a thing called "TFP low power attenuator" that seem to attenuate the power going into DBBPMC, which is between DBB breadboard and the DBB HPO shutter.

Anyway, I wonder how many other significant scattering sources are there on the PSL table. There are other TFP low power attenuators as well as thermal type power meters which might receive some non-negligible power. I don't know which one is essential, but non-essential ones I'd like to temporarily block using black glasses.

2. Power

Stupid thing about this excercize was that the PSL power increased by about 3W when closing the DBB shutter (second attachment, left bottom is PSL power, left mid is the light the DBB REFL diode receives).

Even if you think the scatter causes some problem to the intensity, it should be taken care of by ISS.

It turns out that this doesn't have anything to do with the scatter, it's probably shoddy electronics (design or implementation).

The 1st loop PD actually changes even though the 1st loop is DC-coupled. REF signal is not changing. TRANSFER1_A is just the DCPD scaled and reference voltage added, i.e. PDA_CALI_DC/5+REF.

The "error signal" of the 1st loop is actually TRANSFER1_B (CH10), which is the sum of TRANSFER1_A and TRANSFER2_B.

TRANSFER2_B is the second loop output measured by the 1st loop board, and this should be proportional to the secondloop output measured by the second loop board (CH13). But the second loop was AC-coupled during this measurement.

If you look at all these signals, it's clear that the analog signal downstream of the second loop AC coupling point is pulled by a tiny amount by opening/closing of the DBB shutter (because of the current the driver has to supply?), amplified by the boost stage of the second loop, injected into the first loop, and the first loop dutifully responded by changing the power.

This is not a huge deal as far as we always close the shutter but it's disappointing.

Added 150ml to the crystal chiller.

Diode chiller didn't complain. No water added.

The CW injections have been restarted remotely (after checking with the control room).
I discovered that because of a sign convention change in actuation functions
between S6 and O1, the CW injections with explicit actuation correction were
being injected with a default sign flip. That sign flip has now been removed.

In addition, the amplitudes of pulsar injections 0, 1, 2, 4, 7, 9 and 14 have now
been doubled over what they were in O1. (This amplitude change was supposed
to take effect several months ago, but I had neglected to change a symlink to 
make it so.) 

In detail, the above amplitude changes were accomplished by changing the symlink RELEASE
pointer in the hinj account from O2test to O2_H1_test2 (it was supposed to be
O2_H1_test1 from early summer until now.) The removal of the sign flip was accomplished
by adding an argument --actuationScale=1.0 to the call to lalapps_Makefakedata_v4 for
each of the 15 injections. Previously, the default value for actuationScale was -1.0, a vestige
of iLIGO sign conventions.

I tried for a while today to go back toward our July 16th alignments, as suggested by Sheila in alog 30648.  I put offsets in POP_A and the SOFT loops to try to make the witnesses/oplevs go back toward their July16th values. 

I only made the DARM spectrum worse, not better.  In the attached screenshot, green is the spectrum before I started doing anything, pink is after my alignment work, and red is after taking the offsets out again. 

I also attach a screenshot showing that the buildups and the recycling gain all deteriorated while trying to go back to July's alignment.  To be fair, I was not able to get all optics' witnesses back to their July values, so it's still not really the same alignment, but I think it's closer than what we usually run with.  I don't really think that this is a fruitful direction to continue to persue unfortunately, especially in light of what has just been discovered about the noise improvement when we close the DBB. 

https://alog.ligo-wa.caltech.edu/aLOG/index.php?callRep=30631

Satisfies FAMIS asset 364 maintenance