We now see ETMY PI 18059 Hz (aliased down from 47477 Hz) MODE 28 ring up. It's been successfully damped several locks now with gain +10000, phase +90. These settings have been added to the guardian and SDF. 

I believe this is the same pringle mechanical mode as the 18056 Hz which was originally seen back in July; there's no peak at 18056 Hz now and I was able to ring and damp this by driving ETMY ESD equally in opposite quadrants. 

We've also been battling MODE 27 ETMY 18041 Hz (aliased down from 47495 Hz) the past two nights. Wonderfully, Slawomir just posted a study on these modes earlier this evening. Indeed, we do see both modes ringing up essentially simulataneously (attached: spectrum of three snapshots during the ring up last night. 18041 was being actively damped and 18059 had no damping).

So far we've been unsuccessful at damping MODE 27. MODE 27 ring up very rapidly but for the past few months we've been quickly passing over it during the transient before it had a chance to ring up very much; the recent ring heater changes have shifted the optical mode so that's no longer the case. We had three tries to damp tonight, once with the usual BP + Damping filter set-up, once with PLL, once trying both. All were unsuccessful and we lost lock due to this PI. During this last lock, MODE 27 grew just enough that the drive started to saturate, consequently ringing up MODE 28. I was able to damp the latter by decreasing the gain of the former (and thus not saturating). During this time I tried PLL but it couldn't turn it around. After both seemed damped, MODE 27 rapidly rang up and broke lock. We need to find a smart way to handle stepping the gain to avoid saturation while balancing the need for strong drive. The PLL can do this (we can set a fixed number of counts out so as to avoid saturation) but the PLL doesn't seem to lock onto the modes until too late in the game. Perhaps we consider sending the OMC signal to the PLL for a try?

The fast shutter test that checks that the shutter fires by look at the GS 13s at the time of a lockloss where we had more than 14kW gave us one false alarm tonight. 

(It correctly reported that the shutter did not fire in a lockloss where the circulating power dropped).  Not enough of the power was sent to the AS port for H1:SYS-MOTION_C_SHUTTER_G_TRIGGER_VOLTS to get close to its threshold of 2 Volts.  (screenshot attached)

We probably want to increase this threshold to avoid false alarms so people don't get in the habit of ignoring the warning.  For now I have increased it to 25kW, and committed to the SVN.

Lately we have been aligning DRMI by hand before letting the ASC come on because the ASC engagement has been rough and caused many locklosses. 

Tonight I watched WFS signals while Corey alinged by hand (and the BS drifted in pitch while cooling off from a 50W lock).  It looked like AS45Q was a better signal for the BS than the 36 WFS, with much less sensitivity to other optics.  Hoping that this would help DRMI ASC acquire more smoothly, I tried it out by eyeballing the relative gain.  (where ASB36Q using a 2 in the input matrix, we used a -100 for AS45Q). 

This seems to be working quite well, we have acquired lock with bad alingments about 3 times durring these earthquakes,  and let the gaurdian handle the ASC without aligning by hand. 

We need to switch back to AS36 before we do the CARM offset reduction.

I've moved the DRMI ASC offloading, fast shutter testing, and waiting for BS ISI out of the CARM on TR guardian state (this state was getting crowded with things that are not related to CARM.)  There is now a new state called DRMI_ASC_OFFLOAD that switches MICH to AS36, waits for the ASC to converge, tests the fast shutter if needed, and waits for the BS ISI to isolate stage2.  This happens before CARM on TR. 

Keita, Sheila, Terra

We have had 3 locklosses today caused by saturations of the ISS 1st loop.  There are 2 main messages from this alog:

• ISS diffracted power has been drifting lower and has been adjusted (REF level moved from -1.6 to -1.53, diffracted power now around 3.8%) .  There is a test for ISS diffracted power in DIAG main, but it was compalining today that the diffracted power was too high (rather than too low).   The first attached trend shows a 2 week trend of the diffracted power, the second shows the DIAG main log from today. 
• It looks as though the ISS autolocker might not be helping us (it might be hurting us)

Earlier today, Keita and I had a look at the logic in the ISS autolocker.  It seems that it watches the channel H1:PSL-ISS_TRANSFER1_B_OUTPUT,  if this is above H1:PSL-ISS_SAT_THRES (currently set to 5 V) for more than 10 seconds, it opens the first loop.  In the third attached screnshot you can see this in action right before one of our locklosses.  At just after -14 seconds, TRANSFER1B (bottom row) becomes large and the AOM DRIVER monitor (top right) flatlines.  The PD sums become slightly more noisy for 10 seconds, after which the ISS is opened by the autolocker.  This causes the PD sums to become much noisier, and the hugh glitch in power visible in IM4 TRANS.  Is there any gentler way to deal with a saturation?

Corey, Sheila

Tonight we have very low ground motion (useism band 10^-1 um/second earthquake band 10^-2um/second)

We have been using awggui to add an 8000 count sine wave at 0.1 Hz to the BS M1 LOCK L filter bank (which has a gain of 0.1).  This is helping us to catch fringes more often tonight, and we are manually ramping it off once DRMI locks.   This would be a good idea for operators who find themselves havign trouble locking DRMI in low ground motion.

To do this, use a terminal and type awggui.  Set it up like the attached screenshot.  It is a good idea to start with the gain (bottom middle) set to 0, hit set/run, then ramp the up to 8000 by hitting set in the gain box. 

(Sheila, Terra, Jenne, Matt, Lisa)

Locking Notes:

Had some grief with H1 locking.

• DRMI would lock, but had issues with engaging ASC (so we would tweak up the alignment by hand, enter Guardian commands by hand, and then skip the actual Guardian step to get to DRMI_LOCKED.
• Had issues with a very dead looking Michelson (small ground motion).  Tried various things (PRMI, pushing the BS, lowering trigger values for MICH, etc.)

Before the issues above, managed to get some high power locks to Terra for PI work.

SEI_CONFIG State Change Due To EQ

Additionally, while attempting to lock we had a 6.0 EQ in Colombia which peaked at 1um/s.  I was a few minutes slow, but took the SEI_CONFIG to EARTH_QUAKE_V2 before the noise got to 1um/s.

• 7:32 EARTH_QUAKE_V2 selected (from the default WINDY state)
• 7:55 WINDY selected

Facilities Note:  Noisy Air Conditioning Unit (one closest to entrance) was making a bit of noise.  Bubba was contacted, and this should be addressed tomorrow.  (he said we could turn it off and open the hallway doors if it was too noisy....but we never got to that point.).

I report short analysis on 18038 Hz and 18056 Hz instabilities which  have been frequently observed on both OMC output and the arm transmission QPD.  As it’s been pointed out this instabilities most probably corresponds to the ETMY mechanical modes which are aliased from 47498Hz and  47480Hz.  
In order to observed instabilities around f0 = 47.5 kHz the optomechanical interaction must involve either 2nd or 9th order optical transverse modes. (for FSR = 37.5 kHz and transverse mode spacing, TMS ~ 5.3 KHz, we get f0 ~ FSR +2*TMS kHz or f0 ~ 9*TMS kHz which is the requirement to observe instabilities). Following this argument, optical modes TEM02, TEM10, TEM17, TEM25, TEM33, TEM41 or TEM09 should be considered. I can rule out the 9th order modes since they have large diffraction losses and thus very small chance to cause instability.  According to my FEA model of ETM, there are two spider-like modes: mode #533 and mode #535  (see attachment) which have large overlapping factor with TEM10 (see figure). Computed resonant frequencies are 47454 Hz and  47469 Hz, respectively. Note, these two modes are 16 Hz apart from each other what makes them very interesting. They should ring up at the same time. The overlapping factor for mode #533 is 0.13 on ITM and 0.22 on ETM, whereas for mode #535, the overlapping factor is 0.25 and 0.39 on ITM and ETM. TEM02 gives overlapping parameter of order ~0.001 and can be ignored. 
A larger beam spot size of TEM10 on ETMs is responsible for larger overlapping factor on ETMs than on ITMs.  It is expected that modes #533 and #535 of ETMs are more susceptible to instabilities than ITMs counterparts.
 
Estimated Q-factor for mode #533 is 22e+6 and for mode #535 is 23e+6. Q-factor was estimated based on losses due to HR coating, AR coating, silicate bond, and bulk loss of the substrate.

The last figure (Gain) on the right shows parametric gain as a function of the ETM RoC in the IFO arm where instabilities occur. To compute this figure I used nominal values for aLIGO and P_arm = 200 kW.     

The attachment shows several plots of the CARM error point (as measured by the monitor on the common-mode board) along with the monitor of REFL9I. Both have been referred to volts out of the REFL9 demod board. The left-hand plots show the situation during O1, when there was –13 dB of gain between the summing-node input and the CARM error point monitor. The right-hand plots show the situation as of last night, when the gain was instead +3 dB.

My initial guess is that the improvement in the error point noise is simply due to the gain redistribution between O1 and now, though I have not gone through and budgeted the noise.

[Jenne, Daniel, Ed, JeffB]

While recovering the IFO, Jeff and I could not engage the WFS centering for the AS WFS which needs to happen for us to engage the DRMI ASC.  After some confusion about what the problem was, Daniel suggested that probably the high voltage supply for the fast shutter was off.  We went to the CER mezzanine, and indeed both the OMC PZT and the fast shutter's HV were both off.  This likely happened as a result of some vac/Beckhoff restarts that happened today, which probably triggered the interlock that shuts off the HV when the pressure in HAM6 is too high. As soon as we turned on the high voltage, everything was good again.

So, on the one hand, this is not a situation we expect to run into very often.  On the other hand, we should probably put a test into the DIAG_MAIN guardian indicating that the HV is off so that we don't spend an hour confused again.  There is a test in DIAG_MAIN for the OMC PZT's HV, but that doesn't start looking until we're close to DC readout.  We could just use this, since both HVs will be turned off at the same time.

Some features were added in the model (first attachment):

• Indivisual digital PD signals are fed to PSL-ISS_OUTERLOOP_PDSUMINNER, PDSUMOUTER, RIN_INNER and RIN_OUTER via an input matrix.
  • The input matrix needs to be matched to the analog connection anyway. But this feature would be useful in case we decide to use just one diode, for example.
• PSL-ISS_OUTERLOOP_PWR_NORM is now generated from PDSUMINNER (this used to be changed either manually or by a script).
  • PWR_NORM is used by the AC loop. This is not new, but we don't have to babysit it anymore (second attachment top).
• RIN of inner- and outer-loop sensors are generated by normalizing PDSUMINNER and PDSUMOUTER by PWR_NORM and an appropriate scaling constant.

Closed loop response of the AC coupling was calculated and a filter that mimics its behavior was put in FM6 of the third loop ("ACcpl") (second attachment bottom). Together with FM10 ("white") which mimics the analog whitening of the outer loop error point (which is basically zp=(78mHz^2,3.6^2)), this will make the outer loop transparent when viewed from the 3rd loop.

Kyle R., Joe D.

After years of tolerating "hit or miss" micro-production runs of made-when-ordered vendor spec'd wire seals for Vacuum Bake Oven D (VBOD), we finally convinced them to make a custom batch using our own, in-house, specifications.  No leaks now, so far so good.  The defining difference is that now the seals are slightly undersized and require a slight "stretching" to snap into place on the female flange.  The vendor spec'd ones are fabricated to the final design length and then annealed to the point that they are so soft that they can't be handled without causing them to become elongated during packaging so, by the time we receive them, they are too long and are usually so loose as to be unreliably captured between the flanges.  These, then, and end up leaking 1/2 of the time after the bake cycle (which is very expensive in time and labor to gamble). 

Title:  09/13/2016, Day Shift 15:00 – 23:00 (08:00 –16:00) All times in UTC (PT)
State of H1: IFO is unlocked. Scheduled maintenance day.  
Commissioning: Daniel & Keita commissioning the ISS Second Loop
Outgoing Operator:  N/A
 
Activity Log: All Times in UTC (PT)

14:45 (07:45) Chris – Going to both end stations VEAs
15:00 (08:00) Christina & Karen – Cleaning in the LVEA
15:00 (08:00) Jeff B. & Peter – Forklift old chiller to Mechanical Building (WP #6147)
15:07 (08;07) Chris – Back from End Stations
15:20 (08:20) Jeff & Peter – Finished with chiller move
15:25 (08:25) Alfredo & Elizabeth – Going into Biergarten to make measurements
15:38 (08:38) Alfredo & Elizabeth – Out of LVEA
15:41 (08:41) Filiberto – Going into LVEA to swap ISS Second Loop chassis
15:42 (08:42) Cintas on site to swap mats
15:45 (08:45) Ed – Transitioned LVEA to laser safe (WP #6156)
15:52 (08:52) TJ – Guardian BCS work (WP #6152)
15:55 (08:55) Hugh & Jim – LVEA ITMX HEPI work (WP #6140)
15:56 (08:56) Alfredo – Going into LVEA to look for boards
16:00 (09:00) Filiberto & Marc – Going into CER
16:00 (09:00) Mike L. – Safety audit inspection tour (WP #6150)
16:11 (09:11) Alfredo – Out of the LVEA
16:12 (09:12) Jason – Going into the PSL to reset Power Meter & Check DBB PD
16:15 (09:15) Travis – Going to both End Stations to reset P-Cal camera
16:23 (09:23) Christina – Out of LVEA – Going to End-X to clean
16:43 (09:43) Kyle – Going to End-X for RGA work (WP #6157)
16:44 (09:44) Karen – Finished in the LVEA – Going to End-Y
16:55 (09:55) Filiberto & Marc – Out of CER
17:10 (10:10) Filiberto – Going to Mid-Y to recover cards
17:13 (10:13) Richard, Ed, - Working on BS Binary IO problem
17:15 (10:15) Elizabeth & Alfredo – Out of the LVEA
17:19 (10:19) Jenne – Taking a guest on LVEA tour and to the roof observation platform
17:23 (10:23) Karen – Finished at End-Y
17:30 (10:30) Dave – DAQ restart
17:35 (10:35) Norlco – Delivery of Nitrogen to End-X
17:37 (10:37) Christina – Finished at End-X
17:39 (10:39) Mike L. – Safety Audit finished in LVEA – Going to End-Y
17:40 (10:40) Jason – Out of the PSL
17:47 (10:47) Filiberto – Back from Mid-Y
17:48 (10:48) Filiberto – Pulling cable around HAM4
17:50 (10:50) Hugh – Finished in LVEA
17:53 (10:53) Hugh – Going to End Stations to check HEPI pump stations
18:14 (11:14) Karen – Going to Mid-Y
18:16 (11:16) Jenne – Finished with tour – Out of the LVEA
18:22 (11:22) Karen – Finished at Mid-Y
18:22 (11:22) Christina – Forklifting pallet into the OSB Receiving 
18:25 (11:25) Travis – Finished with P-Cal cameras
18:31 (11:31) Filiberto – Finished in the LVEA
18:41 (11:41) Patrick – Updating user accounts on h1brsex & h1brsey (WP #6154)
18:57 (11:57) Hugh – Back from End Stations
19:52 (12:52) Dave – DAQ restart
20:00 (13:00) Kyle – Leaving End-X
20:10 (13:10) Dave & Nutsinee – TCS Chiller card upgrade
20:50 (13:50) Nutsinee – Going to restart TCS Chillers – Then to LVEA to check TCS
21:00 (14:00) Nutsinee – Out of the LVEA
22:21 (15:21) Ed – Going into CER to check HV power Fast Shutter supply
 

Title: 09/12/2016, Day Shift 15:00 – 23:00 (08:00 – 16:00) All times in UTC (PT)
Support:  Jenne, Dave   
Incoming Operator: Corey

Shift Detail Summary:  Working on relocking after maintenance window.  

WP 6140 FRS 4650 II 1151

DeIsolated ITMY HEPI and cranked on the DSCW Springs to put platform close to target position.  Succeeded generally; 1/12 turn of spring does ~30um shifts--about as small a turn as we can repeatably do (must turn multiple springs the same amount to get desired result.)  But, reduced the 4 horizontal Actuator Drives from ~5000 cts to 10s & few 100s, and, 3 of the 4 vertical drives a good bit.  See 1st attachment.

Different from the BS last week, looking at the local IPS positions, the local postions are pretty much what they were before the drag and drop.  All the IPS readings are within 2 or 300 counts, < 0.0005", see 2nd attachment.  Hmm, now that I revisit the BS numbers, the BS verticals maybe moved 2 or 3x the ITMY...  So maybe all in all not too big a deal given the overcontrolled/constrained nature of the HEPI.

MarcP, Fil, Hugh

This morning, the 'additive' Jameson gave to H1:ISI-BS_BIO_IN_BIO_IN_TEST was still in place and giving a fault to Stage1 V3 Status.  I removed it and it has remained good since except during our testing.

Historically, this has not been glitchy for the past 60 days.  The CD BIO IN must be bad for 10 seconds before the ISI WD triggers and that first occurred at 1230 PDT yesterday.

Around 9am today, monitoring the output from the BIO Chassis going to the I/O computer, the indications were that the V3 channel responds the same as others with very similar logic voltages when the input from the CD was present and absent.  Not terribly satisfying but maybe suggesting the BIO Chassis is okay and implicating the I/O Computer.

Our best test would be to actually have the fault state and repeat this check of the BIO Chassis outputs.

Meanwhile, I hear Richard instructed EdM to power things down and reseat the I/O Computer cards but I haven't heard that directly or seen a log.

FRS 6203

I did not run the matlab plots, if I get a chance later I'll run and post them but no guarantees.

The CO2 heating power was calculated based on Aidan's CO2 power vs. PSL power plot (alog25932). With the new thermal lensing measurement (alog28799) I fine-tuned the equation.

CO2 power = slope * PSL power + offset

ITMX slope was -0.01, now -0.012

ITMY slope was -0.01, now -0.014

ITMX offset was 0.5, now  0.6

ITMY offset was 0.3, now 0.4