Overall message:

• We had trouble powering up today because of the CSOFT radiation pressure instabilty (dPdtheta).  I reshaped the ASC control filter so we should have 20dB of supression, and this seems to have taken care of the problem.
• We have tried to do the coil driver switching twice today, and broken lock both times, seemingly because of a 2 Hz instability that only rings up durring the coild driver switching.  We might want to separate the test mass coil drivers from the triples, so we can narrow down what the problem is.
• We decreased the gain of PRC2Y from -2000 to -14000 to avoid a not very stable ugf at 2 Hz.
• When we power up to 50 Watts with a recycling gain of around 31, the lock only lasts about 20-30 minutes.  There is a slow drift of sideband powers that cannot be fixed by moving PR2 yaw or BS pit or yaw.  It could be a X arm soft yaw drift based on oplevs, we can try using a dither line to monitor the spot position on ETMX and try adjusting the soft offsets this way.

More about CSOFT PIT:

We were using a control filter that had a pair of complex zero compensating the 0.4 Hz resonance, which meant we had very little gain to supress the instability using ASC.  I changed this to a single real zero, which gives us 20 dB gain at the instability frequency. The filter comparison is attached, and a measurement taken at 2 Watts.  In the green measurement I had made a msitake in the filter at 1.5 Hz, the red measurement is with this fixed and the phase should be unchanged from the old design at these frequencies.

Here are some plots to illustrate the alignment progress described in Jenne's alog 29457

The first attachment shows various powers plotted against input power for a power up with the old PRC alignment (blue) and the new PRC alingment (orange). 

You can see that we are still loosing recycling gain as we power up, but less so than with the old alignment.  We know that we can move the PR2/POP offsets a bit more; we stopped where we did last night because we started to rail the POP PZT and had to realign on the in air table.  You can also see that the sideband powers are not dropping quite as much as with the old alignment, although we start with POP 18 lower. 

The bottom row shows REFL normalized by the input power; the plot below shows normalized refl power vs recycling gain.  (Time during the power up goes from right to left on this plot).  You can see that as the alingment gets worse the interferometer is approaching critically coupled, with the old PRC alignment the reflected power starts to increase again for recycling gains below about 27. 

After one of the locklosses in the morning the IMC would not relock. Clearing some of the IMC WFS DOF histories brought it back.
I often had to adjust the BS in pitch to lock on DRMI.
At some point the X arm alignment ended up such that engaging the WFS would drive the green alignment off. Jenne and I trended the optical levers back for ITMX and ETMX and tried bringing these optics back to those values. This did not seem to help so Jenne suggested that I go through an initial alignment. I did and was able to lock both arms on green without difficulty after that.
After the initial alignment we kept losing lock engaging the DRMI ASC loops. Jenne and I stopped at LOCK_DRMI_1F and minimized the ASC loop error signals by hand. Eventually this allowed us to move on.

16:26 UTC Betsy to LVEA west bay
16:31 UTC Kyle to LVEA to take RGA scans
16:51 UTC Betsy done
17:48 UTC Kyle back, not able to take RGA scans
18:51 UTC Chris sending excitation to ITMX
18:53 UTC Kyle back
20:14 UTC Chris sending excitation to ITMX
21:40 UTC Kyle retrieved computer from LVEA
21:49 UTC Starting initial alignment
22:14 UTC Done initial alignment
22:42 UTC Kyle to mid Y to fill CP3

The laser tripped again.  Suspected cause is the same as the trip from earlier this morning.

    Maintenance Tuesday will most likely be quite invasive.

~1550 - 1615 hrs. local -> Kyle to and from Y-mid 

Opened exhaust check-valve bypass-valve, opened LLCV bypass-valve 1/2 turn -> LN2 @ exhaust in 18 minutes 28 seconds -> restored valves to as found configuration.  

NOTE: I increased CP3's LLCV %open value from 20% to 21% in response to the time needed to fill today

I've been looking at the changes in H1 alignment during O1 (13 August 2015 to 5 January 2016) and after O1 (post O1, 5 January 2016 to 27 August 2016).

The chart below shows changes in MC1 alignment drives and OSEM readbacks for pitch and yaw for both time periods.

During O1, MC1 OSEMs change by 33urad and 52urad, pitch and yaw, while the alignment drives change 12urad and 24urad, pitch and yaw.

Post O1, MC1 OSEMs change by 10urad* and 25urad, pitch and yaw, while the alignment drives change 82urad and 46urad, pitch and yaw.

* MC1 OSEM readback for post O1 max - min = 95urad

I'm using MC1 as the measure of the PSL beam pointing, since MC1 is servo'd to center the beam on MC2.

However, the MC1 signal also contains information about the relative positions of HAM2 and HAM3.

HAM3 oplev shows essentially no change in position.

HAM2 oplev shows -26urad change in pitch, and -10urad change in yaw for 45 of the 145 days.  

HAM2 oplev yaw was railled at -39 until November, an then shows a real signal.  Using the 45 days of good data, and applying the change to during that time to the 145 days of O1, the change in HAM2 yaw is -29urad.

Combining MC1 alignment changes and HAM2 alignment changes (measured and calculated):

This suggests the input pointing of the PSL beam changed by +7urad in pitch and +33urad in yaw during O1.

Jenne, Sheila, Patrick

While at ENGAGE_REFL_POP_WFS we took the ISI configuration state from windy to earthquake. This made the cavity power buildup signals noticeably worse. We therefore took the ISI configuration state back to windy.

This occurred around 18:12 UTC.

   These are the 7 day trends for the OpLevs. FAMIS Task #4691. 

The pump diode current readout for diode box 3 has been mis-behaving for a while now.  This time it was caught in the
act.  The set diode current is 50.2 A.  The readout is clearly wrong, not least of which the power supplies cannot
deliver more than ~65 A but also the laser power does not vary during this time.

    Might be an intermittent fault with the Beckhoff terminal that reads the output of the power supply.

Please when the laser trips, disable the locking for the PMC, FSS, and ISS.  It doesn't make
much sense to keep ramping the NPRO PZT when there's no chance of any of the cavities acquiring lock.

CDS:
Continuation of framewriter debugging
Tues: reinstall common mode board

SEI:
Tues: offload BS HEPI DC bias to large springs

VAC:
h0vaclx restarted to fix annulus ion pump channels. Richard reset ITM ESD high voltage.
Kyle turning off pumps

When CO2Y laser had an issue (alog2856) I added a 1 degree offset to the rotation stage calibration to trick it to deliver the right amount of power. That offset has been removed and the CO2Y RS now delivers the right power again.

For higher accuracy the RS random walk script has to be run.

Attached is a capture of the PSL's TwinCAT status screen.  Same problem as previously, namely a flow error in the
AMP cooling circuit.

    In bring the laser back up, I took the opportunity to reboot h1pslctrl0.  This has temporarily fixed the problem
with the diode current readout of diode box 3.

[Sheila, Jenne, Kiwamu, Terra]

We have reset the initial alignment offsets, including realigning several paths on ISCT1, to match the alignment that we liked from yesterday (alog 29430).  So far, we think that it's good.  We have powered up part way twice since, and the power recycling gain no longer drops very much!  It still drops a bit, so we could consider going a bit farther, but this is probably plenty good to move on and focus entirely on low noise efforts.  Now at 40W it is something like 31, rather than something in the mid/low twenties.  Plots coming tomorrow.

In order to do this, we did the following (hardware alignment changes noted in bold):

• Lock using old alignment, at DC Readout move most of the way to the new alignment using PR2 sliders and POP_A offsets.
• Relieve the POP_X centering loop PZT on ISCT1 by *very slowly* moving the knobs on the steering mirror that goes to POP_X.  We were able to do this while locked, and PRC2 was using POP_X in-loop. 
• We then tried to power up with the new alignment to ensure that it was good.  It seemed pretty good (PRC gain stayed roughly constant), but we lost lock due to dPdTheta. 
• For our next lock, we had to lower the threshold at which the POP_X centering loop triggers on, since the beam was partly off the WFS.  (spoiler alert: once we finished all alignment work for the night, this is no longer necessary.  POPX is already quite centered before the centering loop comes on.)
• Once we were relocked with our PR2 slider motion and POPA offsets in place, we set the green input pointing QPD offsets such that the green beams were maximally co-aligned with the IR in the arms, and the green WFS signals were all zero.  This was done at DC Readout, 2W.  We also reset the green ITM camera setpoints.
  • We lost lock while doing this, but the Yarm was already complete.  Sheila did a test InitialAlignment of just the green Yarm and saw that the test masses didn't move according to their oplevs from where we wanted them by more than a few tenths of a microradian.
  • For the Xarm, we put the test masses back to the locations that the oplevs said they wanted to be from the 2W DC Readout lock, and then finished setting the QPD and camera offsets.  The test masses had to be moved by several microradians each in both pitch and yaw to get the unlocked mirrors pointed the same way that they were while being controlled by the ASC loops.
• We centered the green beams on ISCT1 on the green transmission PDs and on the transmission cameras.
• We put PR3 and BS back to the places that their oplevs said they were during our 2W DC Readout lock, then aligned both the ALS Comm and ALS Diff beatnote PDs.
• TJ did an initial alignment for us using the new set points.
• We aligned POPAIR_A and POPAIR_B, although neither was very far off.
• We checked that the DRMI ASC works using the POP_A offsets that we like.  This is now in the guardian, but at some point we should picomotor to recenter POPA in this new place.
  • PRC1 and SRC1 and SRC2 are once again turned on in the DRMI ASC guardian.
  • This makes CHARD come on much more nicely (although we have still had a few locklosses trying to engage these loops).  The gain has been redistributed in the guardian so it also comes on more slowly, but it's apparently still not perfect yet.  At least engaging CHARD makes the recycling gain go up rather than down, which it had been doing until this afternoon (the recycling gain would come back once the PRC1 loop was closed around POPA).
• On our first power up with the new alignment, we lost lock due to the dPdTheta instability.  Kiwamu measured the suppression at the resonance frequency, and increased the gain of the ISS 3rd loop by a factor of 3.
  • Upon our next power up, it seems as though we can't increase the power quite as fast, without causing trouble.  Tomorrow we will try with the ISS 3rd loop gain only up by a factor of 2, and we will also try increasing the power more slowly.
  • Sheila tweaked the CSOFT pitch loop shape so that we no longer have a marginally stable point around 0.45 Hz - this will allow us to increase the gain such that we can help hold against the instability.
• On our next power up, we lost lock with an ISS saturation.  We think this is due to the 3rd loop gain being too high / increasing the power too fast.
• A few minutes later, the PSL shut off.  Commissioning to be continued tomorrow when more photons are available.

Not that this is a surprise or anything, but I was noticing that the light on the OMC trans camera changes noticeably as the IFO thermalizes. 

I've temporarily increased the exposure of the camera to 7000 (usually 569).  You can't see much at 2W, but you start to see it at 20W and 35W - again not so surprising.  What is perhaps more interesting is the way the light there changes after we've been at 50W for a while.  The titles of the attachments include how long we were at each power.  All images were taken during the same lock, so the 2 min at 50W image is after 5 min at 20W, and then 5 min at 35W, so it's not straight 2W->50W on this acquisition.

Since the original images are .tiffs, I've included a screenshot of all 6 images.  Top row, left to right:  2W, 5min@20W, 5min@35W.  Bottom row, left to right:  2min@50W, 6min@50W, 30+min@50W.

S. Dwyer, J. Kissel, C. Gray

After successfully recovering the IMC's VCO and recovering the IMC (29264), we were able to get up through LOCKING_ARMS_GREEN in the lock acquisition sequence. However, we found that ALS COMM failed caused lock losses during the next step (LOCKING_ALS), when the input for IMC length control in its Common Mode Chassis was switched from the IMC's PDH output to the ALS COMM PLL output. The ALS COMM PLL output is connected to IN2 of the IMC chassis that had a new daughter board installed in the star-crossed ISC rack H1-ISC-R1 today (LHO aLOG 29250). After fighting through MEDM screen confusion* at the racks, we found that OUT2 (an analog pickoff pick-off just after the input gain circuit) indicated a ~2.5 [V] offset, even with IN2 terminated with 50 [Ohms]. 

Suspecting that this symptom was indicative that the input gain circuit (circled in red in MEDM screen capture) was yet another causality of the unfortunate rack power mishap today (LHO aLOG 29253), we've replaced the entire chassis (which lives in U14 of H1-ISC-R1) with a spare we found in the EE shop -- S/N S1102627 (or Board S/N S1102627MC). 

Notably, this spare does not have one of the new daughter boards on which Chris has worked so hard.

We're not suggesting this swap be permanent, but we make the swap for tonight at least, so we can hopefully make forward progress. We suggest that IN2 and/or the input gain stage of SN S1102626 be fixed tomorrow, and the chassis restored so we can employ the new daughter board.

Other Details:
- Before removing the chassis, we powered down the entire rack using the voltage sequencer around the back at the top of the rack. 
- After installing the rack, we were sure to have all cables connected appropriately before turning the rack power on again (via the sequencer again).
- We added a few labels to the IMC's PDH output and the ALS COMM PLL output cables such that they're easier to follow and reconnect in the future.

*MEDM Screen Confusion -- whether IN1 or IN2 is fed into OUT2 of all common mode chassis is selectable on their MEDM screens. For the IMC's common mode board (at least for SN S1102626), the MEDM screen's indication of the status of that switch is exactly backwards. When the screen indicates that IN1 is feeding OUT2, IN2 is feeding OUT2, and vice versa. #facepalm