{Gerardo, Chandra}

Replaced faulty PT-110 pressure gauge (SN 217) on HAM6 today with SN 214; however, the hot filament will not come on after some pressure transitions. I've asked Patrick to try to force it on through software when he is on shift tonight. Here is what we did:

1. isolated gauge from HAM6
2. connected aux cart and hung turbo
3. vented gauge tee with room air
4. replaced gauge
5. pumped back down
6. pressure fell as expected into low e-5 Torr range
7. helium leak checked 2-3/4" CF (no leaks beyond 6e-10 Torr-L/s background)
8. valved out turbo and then valved in gauge to main volume
9. pressure is flat lined at 8e-5 Torr, suggesting the filament is not turning on after a pressure spike from isolating "wet" gauge/tee
10. reset gauge, rebooted power, increased gauge pressure --> none triggered the filament
11. next Patrick will run emissions command in software
12. if that doesn't work we will replace with a different model gauge

Gauge is Inficon BCG450-SE and was tested on pump cart prior to installation. IP14 and small 10 l/s IP on RGA both remain stable.

The TSOP for the 520nm laser that was installed a few weeks ago is up. I went down to the end station and removed the power cable, as well as the key. I will remove the entire laser at a later time.

I stopped the HWS code to save a bit of disk space as well.

I added bootstrapping to LASER_PWR node to help us keep our power a bit better. My quick tests to 10W and 25W both worked well, getting under 0.1W  of the target each time.

Include all the measured and modeled transfer functions (with calibrations) taken between this week and last week. This should be pretty much where we operate for the rest of O3. Didn't retake TTFSS transfer function recently but the loop was already well modeled (and had compared it with the real data at one point). The modeled pretty much all checked about except the CLF loop that's missing a factor of ~1.5. 

Fast gain is 0dB unless noted otherwise. Guardian should have all the correct filter settings.

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LO loop (taken with IFO locked)

Calibration: 1.12Vpp at RF3 -14.66dBm.

Common mode board gain (common path): -5dB

Boosts: 0Hz/10Hz, 20Hz/2kHz

Input: In1 for OMC, In2 for HD

CLF loop

Calibration: 2.9Vpp measured at RF6 -2dBm. RF6 was -3dBm during the measurement. Probably close enough.

Common mode board gain common path -9dB, fast path 6dB

Boosts: 0Hz/10Hz, 20Hz/2kHz

Input: Use In2 (Q)

OPO loop

Calibration: 164mVpp measured at 0.4mW input power to the OPO. 3.57mW input power to OPO during the measurement

Common mode board gain (common path): -13dB

Boosts: 0Hz/10Hz, slow path 4Hz/400Hz

SHG loop

Calibration: 79mVpp measured at 1.8mW transmitted power

Comments: Low UGF because the loop inject (possibly) mechanical noise that shows up in CLF spectrum (alog52755). So far this hasn't been a problem.

Common mode board gain (common path): 7dB

Boosts: 0Hz/10Hz, slow path 4Hz/400Hz

TTFSS (Beckhoff control)

Attached below are the results for the charge measurements performed on the ETMX and ETMY (post Oct 2019 vent break).

ETMX: There has been a definite rise in the charge accumulations on all 4 quadrant for the pitch and yaw mode. The first and the 4th quadrant for the pitch mode shows an average bias voltage of +40V and +20V respectively. The  bias voltage on the 2nd, 3rd and 4th quadrant for the pitch mode has jumped by 10-20V.  For the Yaw mode, the 1st and the 3rd quadrant are at 50V, which is quite high. The 3rd quadrant is just above 40V.

I will discuss these results with J. Kissel to see if we need to flip the sign yet.

ETMY: There hasn't been a huge change and the effective bias voltage on most of the quadrant has remained the same or declined. The biggest fall has been seen on the 2nd quadrant (Yaw). The rest of them are between 0-20V.

The slider values were restored after the measurement was complete, and any SDF difference was removed.

Continuing from conclusion of aLOG.

I have sought to import SUS models into foton using the foton.py library linked in the last alog, which was written by Lee McCuller.

I have produced a script which takes the TST transfer function to update the foton filters for Pcal via a python script, avoiding the need to 'quack' the filter with matlab scripts.

The quack scripts have a lot of error handling so that filters are compatible with foton. Here I directly input the filters with foton, with all its built in error handling.

I produce a filter that is arguably more accurate than what matlab is putting into foton... since I handle the DC gain with more precision.

I compare how matlab and my script fare against the original intended TF, by comparing the TFs that foton sees the inputs to be. You will note that the TF's have a bit of an error in magnitude at high frequency, I suspect that is due to the fact that the 1/f^2 filter (titled '1:1') is built within foton, and there is some difference from the system modelled in matlab.

Caveats of this process:
Until there is an update to the python control library, there is no clean way of recovering to true DC gain of a ZPK TF, without importing the SS model generated by matlab. One also needs to import the ZPK model generated by matlab, because the python control library doesn't make the same changes to the SS to produce the ZPK, and I get a bit of a magnitude error at around 2 Hz.
Hence, I end up importing both the SS and ZPK models that matlab spits out, which is not great.

If you want to play with this, be concious that you must change paths to things.

I will be putting this in the relevant places in the CalSVN, and writing up some more robust documentation going forward.

We have been chasing the reason for th3e range drops all day today. Here is another negative:

Suspecting something like "microwhistles" I made a 30sec spectrogram before and after the range drop. I don't see any difference in the statistics.

Good: GPS 1256894801
Bad:   GPS 1256914735

Plot 1: Range, the date in the spectrogram corresponds to the first 30seconds (good) and the last 30 seconds (bad).
Plot 2: Spectrogram of the good time.
Plot 3: Spectrogram of the bad time.

==============

Plot 4 and plot 5 show spectrogram centered around the range drop at GPS 1256913467. (plot 4 GPS start 1256913437, plot 5 GPS start 1256913452,)
Note the slight increase in the noise level, but no associated pattern whatsoever. The range indeed dropped within 1 second.
Finally, plot 6 shows histograms of the PSD values before and after the range drop, renormalizing with the mean. Both histograms are indistingushable from an exponmential distribution.

Ethan, Sheila

We ran BruCo over 10 minutes worth of data during yesterday's unexplained range drop. No channels had significant unexpected coherence with DELTAL_EXTERNAL.
The summary of results is located here.

An analysis with LASSO is next on the agenda.

TITLE: 11/05 Day Shift: 16:00-00:00 UTC (08:00-16:00 PST), all times posted in UTC
STATE of H1: Preventive Maintenance
OUTGOING OPERATOR: Jeff
CURRENT ENVIRONMENT:
    SEI_CONF state: SC_OFF_NOBRSXY
    Wind: 1mph Gusts, 0mph 5min avg
    Primary useism: 0.01 μm/s
    Secondary useism: 0.13 μm/s
QUICK SUMMARY: Killed the lock to start measurements and Maintenance Day.

   Dropped out of Observing from 15:12 (07:12) to 15:24 (07:24) to run the PEM injections. 

   Posted below are the plots from the weekly ISI CPS noise spectra. BS_ST2_CPSINF_V1_I is reporting elevated high frequency noise. The other plots look OK. 

Closing FAMIS #12872

   At Mid-shift all is well. 

In the movie linked in alog 52927 we saw the phase camera begining to fail in a way we hadn't seen before, around 35s into the movie. We ran it again during throughout the lock acquisition today and it lasted much longer into the lock however it started to happen again. It seems the resonant circuit used to drive the pockel cell has reached some temperature limit after prolonged use. When we reduce the driving voltage by half we start seeing the same images as we did before, except with 50% reduction in amplitude. Leaving it to cool down also seems to fix the problem for the first few images but the it starts up quickly again. Something to be fixed in the next version.

We also wanted to try the CO2X test again (agreed with Keita) where we drop CO2X and then raise it up again to see how the carrier+sideband mode matching changes. The change will be small +-100mW left over an hour. Short jumps out and back into observing will be required, I'll comment GPS times when we start.

However we just had yet another GRB event so we're standing down again, hopefully can try this later.

earlier today I tried loading a new PRCL FF filter, which I did not load.  That is why there is an orange block on the CDS overview for LSC, but it has no impact on the interferometer. 

TITLE: 11/04 Day Shift: 16:00-00:00 UTC (08:00-16:00 PST), all times posted in UTC
STATE of H1: Observing at 115Mpc
INCOMING OPERATOR: Patrick
SHIFT SUMMARY: H1 in Observe, instrument air pumps for LVEA are working, SQZ just fixed itself, causing an increase in range
LOG:

VACUUM:

• 15:06:24 - first vacuum alarm for PT199
• 15:19:42UTC - JeffB turns on the pump(s)
• 15:20:16UTC - JeffB turns off the pump(s)
• 15:25:44UTC - preassure levels off at 41.7PSIG
• 15:28:31UTC - JeffB turns the pump(s) on, at 41.6PSIG
• 15:43:15UTC - JeffB turns the pump(s) off
• 15:54:09UTC - Kyle is here, turns the pumps on, pressure 75.2PSIG
• 16:02:290UTC - Kyle turns the pumps off, valves out the LVEA, pressure 98PSIG
• 17:01:12UTC - Kyle turns the pumps back on, valves the LVEA back in, pressure 89PSIG
• 17:23:57UTC - pressure is at lowest point, 62.9PSIG, and pumps come back on
• since then pumps running between 62PSIG and 88PSIG

SQZ:

• 17:24UTC - H1 range drops
• 17:46UTC - H1 out of Observe, I take all SQZ guardians (except beatnote) through INIT to DOWN
• 17:48UTC - SQZ is relocked, no change in range
• 17:56UTC - SQZ guardians  to down, cleared SQZ ASC, would not recommend
• 18:13UTC - SQZ relocks, after I restore ZM1 and ZM2 pointing, not exactly, but close
• 18:17UTC - H1 back in Observe
• 23:44UTC - H1 range goes up, ZM1 yaw changes direction

We were seeing "frequency noise" become very apparent in DARM again.
("frequency noise" is in quotes because it is the underlying cause, but probably not the direct agent actually putting noise into DARM.  That honor belongs to intensity noise.)

We've seen a continued plummet in the reference cavity transmission over the last week.  We are now at the point where the ref cav transmission has dropped 47%.  (Attachment 1)
Jason posted in alog 52882 about trying to fix up the alignment, with some success in recovering some transmitted power (seen in attachment 1 between -200000 and -100000 seconds ago), but not resolving the underlying issue.
Probably the best witness of FSS health is the IMC_REFL_DC signal (red trace, first and second attachment).  When signal goes above ~10 mW, we are likely to be having frequency stabilization problems originating in the FSS, high high-frequency noise in DARM, and worse range.

I increased the FSS common gain from 23 to 25 dB
In the first PDF attachment, we see DARM and laser noise coherence at FSS gains of 23, 24, and 25.  
After increasing from 23 to 24 dB, pretty much all the "frequency noise" we were seeing in DARM went away.  There is no apparent change in laser noise coupling when increasing from 24 to 25 dB.

ASDs:
In the second PDF attachment, I plot DARM, CARM, and ISS secondloop ASDs before and after the FSS gain increase.
It's clear that the noise levels of all go down significantly. 
 
I expected there to be significant coherence between the ISS and CARM, but this is not the case.

Coupling:
In the third PDF attachment, we see there is high coherence between the ISS secondloop and DARM with lower FSS gain, and much smaller coherence after the gain is increased by one dB.
In the fourth PDF attachment we see low coherence between DARM and CARM at all times, likely because the true frequency noise is drowned out by the high intensity noise apparent in DARM.
However, at no time is there coherence between CARM, IMC, or FSS error signals and the ISS loop. (fifth, sixth, seventh PDF attachments)

Jury is still out on why falling FSS gain causes high intensity noise.  I would have thought this sort of intensity noise would be generated by the frequency noise incident on the IMC.  
It is possible that this noise coupling is nonlinear, or I have looked at the incorrect witnesses.

The end station laser locking ran away when the reference cavity was unlocked earlier today. When PSL tries to relock the reference cavity it searches for a resanance by changing the PSL frequency substabtially. The end station lasers try to follow but eventually lost it and went into lala land.

In the past this didn't happen because the end station laser locking would automatically pause, when the reference cavity was unlocked. When we changed the PSL fiber pick-off, we moved the monitor PD as well and it now just monitors the power after the PMC. The PD after the reference cavity is still there, so we should conect it to a spare channel in the auxiliary signals concentrator 3.