Jeff K, Chris Whittle

Following on aLOG 28363 (initial proposal) and 29250 (installation), we measured the open loop gain of the IMC loop (without full CARM) with the AG4395A, both with and without the daughter board 200 kHz pole. The GPIB is still connected to the AG4395A by the Common Mode Board.

TFAG4395A_15-09-2016_140247.txt has the transfer function without the daughter board, TFAG4395A_15-09-2016_140553.txt with the daughter board. The attached plots were generated with daughter_tf_plots.py.

See the attached plots of open loop gain, loop suppression and closed loop gain. Takeaways:

• features around 800 kHz suppressed by 200 kHz pole
• we still have 48° of phase margin compared to our previous 63°
• unity gain frequency has moved from 75kHz to 64kHz
• gain margin has increased from 2.7 dB to 4.6 dB
• maximum gain peaking in the loop suppression has been reduced from 4 to 2.5
• closed loop gain is relatively unchanged below 40 kHz and should not affect CARM loop

Also note some variation in the OLG at about 200 kHz compared to the previous measurement.

Added 200mL to the crystal chiller.

FAMIS#6488

State of H1: unlocked, maintenance activities

Activities:

• 15:10 - Peter - PSL - alignment
• 15:20 - Fil - LVEA vertext - pulling cables
• 15:43 - Kyle - EX VEA - vacuum
• 15:43 - Betsy - LVEA - parts
• 16:00 - Gerardo - MX and EX - ion pump swap
• 16:30 - Dave - restart LSC to load new code
• 16:30 - MikeL - LVEA - tour
• 16:37 - Kiwamu - LVEA - tour
• 17:00 - MikeL - done
• 17:05 - Kiwamu - done
• 17:14 - Betsy - done
• 17:34 - Peter - done
• 17:37 - Dave restarting LSC and ISS code and DAQ
• 17:37 - JeffB - diode room
• 17:43 - JimW - EY - BRS, ion pump might not be on
• 18:25 - Betsy - LVEA - iLigo and 3IFO TCS parts
• 18:43 - Betsy - done - found two
• 19:00 - ChrisWhittle and JeffK - LVEA - GPIB

As of 20:29UTC:

• ChrisWhittle and JeffK - done
• JimW - done
• JeffB - done
• Dave - done
• Gerardo - done
• Kyle - done
• Fil - done

Commissining Work:  LSC and ISS

Daniel, Keita, Dave:

we installed new versions of h1psliss and h1lsc. This required a DAQ restart.

A brief history of IP10, the controller for IP10 had A channel go somewhat bad on 9/3/2016, controller was set to output 5k volts but its output was only able to do about 2k, then we had a power glitch on 9/10/2016, that caused the current output to go down and the pressure to go up (see attached graph).

Since IP12 is currently valved out, where the pump is pumping on a small volume, we decided to swap controllers between pumps.  So for now IP12 will show some alarm values until the controller is fixed.  And to keep the small volume at IP12 good, we are pumping with one channel despite of what the signal says.

The factory flanged flange containing the inadequate fasteners was "gappy" enough that I tried the easy in-situ replacement of its fasteners but unfortunately it didn't work (2x10-8 torr*L/sec leak) and I had to vent the RGA volume and replace the gasket along with adding the good fasteners -> pumped down RGA volume and leak tested new joint -> No leak detected (Leak Detector baseline signal 3.5 x 10-9 torr*L/sec helium).  I didn't have the RGA laptop so I'll need to go out again at the next interferometer (IFO) downtime to verify the the RGA works after having being withdrawn from and reinserted into its protective nipple (this exercise can result in a grounding of some of the tight clearance electrodes upon re-insertion).  

Leaving work area shut down, i.e. there are no pumps running or related electronics energized etc. 

I have increased the chilled water set point by 5 degrees F to 45 F on the corner station chiller.

After tweaking the alignment into the pre-modecleaner, I measured the power noise spectra
for both photodiodes PDA and PDB when either was used as the in-the-loop sensor.

    The plot PDA.png is for when PDA was used as the in-the-loop sensor.  PDB.png is for when
PDB is used as the in-the-loop sensor.  When the ISS is off, in both cases the free-running
power noise measurements agree quite well.  However the in-the-loop and out-of-the-loop spectra
disagree quite badly when PDB is used as the in-the-loop sensor.  The in-the-loop noise suggests
there's enough gain in the loop in this case with the level being ~1.0E-8.  The out-of-the-loop
spectrum is more than a factor of 10 higher, which suggests there's a difference in the two optical
paths (most likely beam pointing).

    Not sure why at this stage.  I would probably use PDA as the photodiode to be used as the
loop sensor (for now).

The BRS at EY has had a long term drift requiring periodic recentering. That drift seems to have stopped or changed sign, following the power outage on Saturday. Attached image is a 60 day trend for H1:ISI-GND_BRS_ETMY_DRIFTMON. The black streaks are from when the BRS went out of range and when it was recentered during Krishna's last visit. The little blip up to zero at the end is from the power outage, before the commissioners recovered the BRS code. Second image is the last 6 days, outage is when the signal goes to zero. Definitely looks like the drift has changed sign.

Dave, Patrick

Restarted all web medm screenshots on script0.

And all other driver dofs are quiet as well.  Remember, Monday night 29667, this channel, H1:ISI-BS_BIO_IN_CD_ST1_V3_STATUS, was dropping to zero, indicating a thermal problem.  Checks suggested the coil driver was not actually sending the bad signal and the BIO Chassis was responding appropriately to simulated state changes.  The I/O computer cards were reseated and by default, all the machines were power cycled.  Maybe we've seen the last of this issue for the time.

Sheila, Matt, Lisa

The ISS has been oscillating a couple of times when reaching 50W in the last two locks. Sheila fixed that by turning off the AC coupling.

We leave the IFO locked at 50W with the ISS AC coupling off, at Sep 15, 9.45UTC. It has been locked for about 20 minutes, powers are stable, no PIs.

Matt updated SDF with the latest PI settings.

We just noted that the PSL NOISE EATER is oscillating -- so please fix that in the morning.

Sheila, Lisa, trying to summarize the work of many people today

* More  Intensity Stabilization Science   made possible to engage all of the ISS loops and lock several times at 50W;

* The lock at 50W had been broken earlier today due to the inability to damp the ETMY Mode 27 (18041 Hz). This triggered the decision to turn off the EMTY ring heater (see  Terra's elog ). After that we had a couple of stable locks at 50W, when Terra and Matt were able to keep all the Pis damped, and the sideband power and the recycling gain were stable. As Kiwamu already observed, it looks like the current combination of ITM ring heaters and CO2 powers is good (enough) to prevent the sideband power and the recycling gain from dropping (note: Corey and Kiwamu noticed a drop in AS90 in another 50W lock later in the evening (see   Corey's entry ) and they had to deal with some PI damping, but that lock was done with no CO2 X power, instead of 400 mW, as Kiwamu was exploring CO2 tuning);


* After more than 2 hours at 50W we started some low noise steps. Evan engaged the OMC whitening filters, but that didn't help at all unfortunately, as we are entirely dominated by intensity noise above 300 Hz. Looking at the noise budget from O1, a by-eye estimate tells us that the current level of intensity noise is at least ~300 times worse than during O1, even more at some frequencies. The noise is also worse than what it was during ER9 (when the HPO was operational). Sheila's entry  shows indeed that the intensity noise coupling to the interferometer is about 3 times worse than it was during O1; also, the ISS out of loop sensor is about 3 times higher than previously measured, showing coherence with PSL accelerometers. If you add that the current ISS loop has a factor of 2 less gain than during O1, while the intensity noise with the HPO is 30 times higher, well..the factor of 300 worse noise than during O1 makes sense.

So the bottom line is:

* we are close to a stable 50W configuration, it looks like PIs can be controlled, and the sideband power can be stable; need to work on robustness from lock to lock;

* the intensity noise is huge, and it dominates the noise above 300 Hz; trying to get more gain out of the current ISS loop didn't prove successful tonight, so we need a better strategy. Probably we should start by going in the PSL and realign the PMC and see if it improves the ISS out of loop PD spectrum.

Lisa, Sheila

We have had 2 more incidents of locklosses where the ISS autolocker unlocks the interferometer in response to an ISS saturation. (described last night as well)

Here is a plot very similar to last nights, showing one of these locklosses. 

Sheila, Lisa, Keita, Daniel, ...

Here are a few plots ilustrating our intensity noise situation.

• The first attachment is the spectrum taken after 1 hour at 50 Watts, with ASC in the high bandwidth state, so the ASC noise dominates up to 300 Hz.  You can see that there is a high coherence with intensity noise (yellow) above a few hundred Hz, and frequency noise coherence is large above a few kHz. At the peaks of intensity noise there is coherence with all the PSL accelerometers, microphones, ect.
• The coupling of intensity noise (measured passively) is shown in the second attachment. This is about a factor of 3 worse the the coupling measured by Evan durring O1 (25476)
• The alingment of the PMC was better in July than it is now. (last attachment).  This may explain some jitter to intensity noise coupling on the PSL table which shows up as more noise in the ISS loop.
• The intensity noise from the first loop is worse than when Evan and Keita measured it in February 26773.  (last attachment, PDB is now the out of loop sensor, this was measured with the second loop off so it should be comparable to the attachment from February).  There are several broad accoustic peaks in the new spectrum that aren't in the February spectrum, and have coherence with PSL table accelerometers between 100Hz and 1 kHz.  The out of loop sensor is a factor of 5 more noisy at 100 Hz, and there are frequencies where it is a factor of 10 worse, after the IMC things are a factor of 3-5 worse. 

It seems possible that a worse alingment on the PSL table since July (ER9) is contributing to our worse intensity noise.  It might be worth considering a PSL incursion to align through the PMC better to take care of some of these peaks, as seen by the first loop PDs at least. 

Walked in to a locked H1 and several tests going on.  After a while H1 dropped out & then Daniel/Keita ran some ISS arm power scaling tests.  

After these tests I wanted to get H1 locked up at High Power.  Similarly to last night DRMI & PRMI locking looked quiet.  So I went & used Sheila's trick of pushing the BS (see note in her alog about this & how to end the excitation).  This seemed to work in that PRMI was able to lock up...but I also tweaked the BS to bump up the PRMI flashes.

Took H1 up to INCREASE_POWER (I assumed it would take H1 to 30W, but it actually kept on going....at around 54W, I went ahead and selected 50W.).  I kept H1 at 50W for some high power locking.  Here are some notes from the lock thus far:

• After a few minutes, the PI MODE27 rung up, but it went back down without any action.
• MODE26 slowly started to ring up.  Since I had never dealt with PIs before, I grabbed Kiwamu for help.  This mode was using PLL to damp the mode.  When we looked at the mode, it wasn't large enough to lock the PLL so it could damp it out....BUT, Kiwamu noticed that if the PLL were to lock it up, it would excite the mode, because it had the wrong sign (+1.00).  Kiwamu changed it to -1.00 and then this damped out (after a quick test which Kiwamu showed me regarding the sign).
• MODE25 & MODE17 then rung up.  After some sign changes, Kiwamu determined that MODE17 did not have a small enough band pass & was observing crosscoupling from the true culprit:  MODE25.  Kiwamu worked on damping this guy out, but then we lost lock surprisingly (we had been noticing AS90 drifting down over our 90min lock.

FOM/Nuc5 Note:

I tried to fix nuc5, but after reboot, the seismic DMT viewers  were not getting data from correct time.  Is this a kerberos ticket issue?  Do we have instructions on this?

Seismic Config Note:

EX was taken to Windy NO BRS because Nutsinee was going to go in the VEA & just wanted to be safe.  EX ISI was returned to Windy config after she exited the VEA.  In hindsight, looks like we didn't need to do anything (her incursion wasn't seen on the STS).