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. 

TITLE: 10/18 Day Shift: 15:00-23:00 UTC (16:00-00:00 PST), all times posted in UTC
STATE of H1: Lock Aquisition

SHIFT SUMMARY: Locking has been better today, but ITMY bounce modes16:00 Kyle to EX

2:30 pm local

Took 3 min. 30 sec. to overfill CP3 with 1/2 turn open on bypass LLCV. Newly installed thermocouples in exhaust pipe (a few feet up the vertical run) responded well to LN2. On Friday let's overfill by doubling LLCV setting (to ~34% open) and see how long it takes for LN2 to trickle out. Meanwhile I've increased LLCV from 16% to 17% open.

3600 second trend attached. As soon as I opened the bypass valve I saw a {small} dip in temperature. 

Sheila, Terra, Jeff K, Patrick, Nutsinee

Tonight we continued with the PRMI locking difficulties of yesterday.  Nutsinee managed to lock PRMI by lowering the MICH gain and commenting the boost and offloading out of the guardian. 

Patrick tracked down some differences between the "good" PRMI time that Jenne mentioned (Oct 17 16:03 UTC) and now, there was a filter missing in the BS top mass offloading, and two whtening stages (with the anti whitening) were engaged in the middle of the lock yesterday afternoon.  We don't know why this happened, but just undoing it actually makes it impossible to lock at all. 

To match the PRCL loop shape to a reference, I had to add 6 db of gain (PRCL digital gain of 16 rather than 8).   However it looks like we still missing some kind of boost in PRCL (1st screenshot).  The second screenshot shows the MICH loop measured today on the left, before and after the PRCL fix, and an old measurement on the left. 

We have commented out the boost and offloading of MICH in the guardian for PRMI, and nutsinee created  new prmi_mich_gain_als and prmi_prcl_gain_als parameters in lscparams, and we have set them to 0.7 and 16 for now, although the nominal values should be 1.4 and 8.  You will have to reduce the MICH gain by hand to get it lock. 

Could who ever did some measurements that required changing the REFLAIR whitnening gain triple check that whatever they did is not causing us problems in the morning?

Evan G., Chris B., Rick S.

Summary:
We started the INJ_TRANS guardian node, but due to a time zone issue in the gpstime python module, we couldn't schedule injections to verify the code was doing the right thing. We will come back to make the final tests once the time zone issue is sorted out. 

Details:
To do this test, we logged into the guardian machine and updated the guardian SVN to get the latest and greatest updates from Chris.

Then, because the guardian node for INJ_TRANS was not running, we started it by
$ guardctrl create INJ_TRANS; guardctrl start INJ_TRANS

We added a test injection to the new schedule file, set an injection time in the near future, and verified it by the following:
$ PYTHONPATH=/opt/rtcds/userapps/release/cal/common/guardian:${PYTHONPATH}
$ CAL_USER_APPS=/opt/rtcds/userapps/release/cal/common
$ python ${CAL_USER_APPS}/scripts/guardian_inj_schedule_validation.py --schedule ${CAL_USER_APPS}/guardian/schedule/schedule_1160692574.txt --min-cadence 300 --ifos H1

The state of the guardian never changed as it should have, so after some debugging, we found the difference in the GPS time the node thinks it is versus what GPS time it really is, is about 7 hours. It is likely due to the fact we got the following warning when starting the guardian node:
/ligo/apps/linux-x86_64/gpstime/lib/python2.7/site-packages/gpstime-0.1.2-py2.7.egg/gpstime/__init__.py:220: RuntimeWarning: GPS converstion requires timezone info.  Assuming local time...
  RuntimeWarning).

Chris is going to investigate how to set the time zone info for the GPS module before we try again to fully test the infrastructure

As mentioned in alog 30663, we have a slightly new infrastructure for balancing the OMC DCPDs.  I used the method that JeffK et al. used in alog 29856 to measure the imbalance between A and B. 

I'm not sure why I'm getting a different value for the imbalance than they did (I get that the ratio of B/A = 0.969 rather than their 0.958).  Perhaps we should look at how this number is actually changing over time, if it is.

Anyhow, the balancing matrix is now populated.  See screenshot for values.

Don't have remote monitoring and will need to enter X-end VEA to make measurements sometime this afternoon.

The first attached screenshot is a series of DCPD spectra from the last several months.  When we first turned on the HPO, the noise in DARM did not get any worse.  The noise stayed similar to O1 until July 16th, the lump from 200-1kHz started to appear in late July, when we started a series of changes in alignment and TCS to keep us stable with a decent recycling gain at 50 Watts.  

PMC

Last night, Gabriele pointed out that the noise in DARM is coherent with the PMC HV.  The HV readback had been mostly some white noise (probably ADC noise), until the last few weeks, but has been getting noisier so that some of the things jitter peaks show up in it now (SEcond attached screenshot, colors corespond to the dates in the DCPD spectrum legend.  This may be related to the problem described in LLO alogs 16186 and 15986.  The PMC transmision has been degrading since July, which could be a symptom of misalingment.  Since July, the REFL power has nearly doubled from 22 to 38 Watts, while the transmission has dropped 28%.  The PMC sum has also dropped by 4%, roughly consistent with the 3% drop in the power out of the laser.  Peter and Jason are planning on realigning the PMC in the morning, so it will be interesting to see if we see any difference in the HV readback.  

TCS + PRC alignment:

The other two main changes we have had in this time are changes in the alignment through the PRC, and changes to TCS.  These things were done to improve our recycling gain and stability without watching the noise impact carefully.  In July we were using no offsets in the POP A QPDs.  We started changing the offsets on August 1st, after the lumpy noise first appeared around July 22nd.  We have continued to change them every few weeks since then, but generally moving in the same direction.  

The only TCS change that directly coresponds to the dates when our noise got worse was the reduction of ETMY RH from 0.75 W each on July 22nd, the other main TCS changes happened September 10th.  It would be nice to undo some of these changes before turning off the HPO, even if it means reduing the power to be stable.  

Work Permit Number: 6252

The DMT calibration has been updated to gstlal-calibration 1.0.6-2.el7. Because of dependencies GDS was also updated to: gds-2.17.10-2.

John Zweizig has restarted the DMT monitors.