- Started with checking the ISC guardians into svn.

- Designed a set of arm ASC filters for 25W using the following simple interpolation for the filter zeroes and Qs:
   f^2 = (f_0)^2  + [(f_50)^2-(f_0)^2]*P/50W  (Frequency squared should be linear in power, with the offset given by the stand-alone suspension.)  
   Q  =interp1([f_0,f_50],[Q_0,Q_50],f,'linear')  (Linear interpolation for the Q's between the stand-alone frequency and 50W frequency)
  The same procedure was applied to both resonences in each transfer function. The detailed frequencies and Qs are in the attachement.
   Looking at Jenne's full model, this should be relatively close to the truth.

- Then I rewrote the LOWNOISE_ASC guardian state to choose the new 25W filters below 40W, and the old 50W filters above 45W.

- We'll test all this as soon as the IFO is back.

J. Kissel, D. Barker, S. Aston
Work Permit 6263
Integration Issue: 1193
ECR E1600028

As a result of us now computing the suspension point projections in the SEI front-end models, we no longer need to waste Dolphin IPC connections or SUS computation cycles calculating these projections in the SUS front-end models. As such, with the help of updated library parts from LLO, I've removed the calculation from all SUS models. Thanks to all the hard work Stuart put in, all this required was a slow and steady update to the following library parts:
/opt/rtcds/userapps/release/sus/common/models/
        *    14081   HLTS_MASTER.mdl
        *    14081   BSFM_MASTER.mdl
        *    14081   SIXOSEM_T_STAGE_MASTER.mdl
        *    14081   TMTS_MASTER.mdl
        *    14081   QUAD_MASTER.mdl
        *    14081   QUAD_ITM_MASTER.mdl
        *    14081   SIXOSEM_F_STAGE_MASTER.mdl
        *    14081   MC_MASTER.mdl
        *    14081   OMCS_MASTER.mdl
        *    14081   HSSS_MASTER.mdl
        *    14081   HSTS_MASTER.mdl
and shifting all top-level connections to these library parts up to recover from the missing input ports. Note, I did have to make my own modifications to the 
/opt/rtcds/userapps/release/sus/common/models/
M            14081   RC_MASTER.mdl
part, in the same fashion as the HSTS and MC master parts. Not too bad, and this *wasn't* done at LLO, because none of their triple suspensions have the increased drive range (see E1400369).

I've test compiled all of the following top-level models that have been changed:
/opt/rtcds/userapps/trunk/sus/h1/models/
M       h1susetmy.mdl
M       h1susetmx.mdl
M       h1susitmx.mdl
M       h1susitmy.mdl
M       h1sushtts.mdl
M       h1susprm.mdl
M       h1sussrm.mdl
M       h1suspr2.mdl
M       h1suspr3.mdl
M       h1susbs.mdl
M       h1sussr2.mdl
M       h1sussr3.mdl
M       h1susomc.mdl
M       h1susmc1.mdl
M       h1susmc2.mdl
M       h1susmc3.mdl
M       h1sustmsx.mdl
M       h1sustmsy.mdl
M       h1susim.mdl

and have committed them to the userapps repo. These model changes will not be installed until next Tuesday.

TITLE: 10/21 Day Shift: 15:00-23:00 UTC, all times posted in UTC
STATE of H1: Locking
SHIFT SUMMARY: Mostly down for maintenance for today, DRMI is being difficult

16:00 Peter to PSL area, out 19:00

WP6262

Picomotor control signal cable (ISC_293) was disconnected from ISCT1 along with panel D1101691 and pulled outside the PSL enclosure. Inside the enclosure both D1101691 and D1101738 will be used to transistion from DB25 to DB9 to RJ-9 connections. Picomotors signal paths tested good.

F Clara,  M. Pirello

We measured the noise spectrum on the Primary Mode Cleaner (PMC) power supply in the CER mezzanine, per WP#6261

The raw scans are attached to this log, the probe is 10x attenuated, and the raw data does not take this into account.

2:20 pm local

Took 90 sec. to overfill CP3 by doubling the LLCV setting to 34% open rather than cracking the bypass valve. I am dissatisfied with the TC readings. Temps never registered below 0degC. But there is still a decent delta.

On Monday I'll fill the same way and allow LN2 to exhaust a little longer to see if the TCs eventually read appropriate temps. 

I connected the second SR560 to the HPO injection lock HV monitor with the same setting as the PMC length PZT monitor. Blue is the injection lock, red is the PMC length PZT.

Known peaks in PMC PZT, i.e. 240Hz, 320, 480, 600 and 1kHz are all much more prominent in the injection lock feedback.

Unsurprisingly, opening/closing DBB shutters, plugging off the shutter cables, turning off HV of DBB, and completely powering off the DBB crate didn't affect the peak height of the PMC PZT as well as injection lock. (green and brown are when the DBB crate was fully powered and the shutters were closed, red and blue are with the DBB crate totally powered off and the shutter cables disconnected.)

I left DBB crate unpowered and shutter cables disconnected.

I left the injection lock monitor connected to the SR560 and the second LSC-EXTRA_AI channel.

Peter installed a cable running into the PSL and into the excitation port of the 9 MHz RF driver, so we can now excite 9 MHz RFAM with the DAC.

J. Kissel, B. Weaver,

Betsy had taken measurements on Tuesday 10/18, but we've only gotten around to processing and posting the trend now. Measurements show the same story as last week -- we're ready for a bias sign flip; all effective bias voltages are around 10 [V], and we 'd like to keep it that way. We'll make the change at the earliest convenience (it's never convenient). 

Summary:

There is a broad peak in the DARM spectrum around 5kHz which is consistent with the TEM10 being rung up at that frequency. 

• The transient behaviour is consistent with the simulated change in g-factor (and HOM spacing) of the cavity due to self-heating of the optics causing the ITM and ETM surface curvatures to change
• The observed peak in DARM shifted down in frequency after the ETMY ring heater values were changed (as expected).

Details:

The attached MATLAB file produces an animation that shows the DARM spectrum around 4700 - 5500 Hz. It updates this spectrum for 50s intervals around the time that the IFO is locked. Very quickly we see a broad peak (around 50Hz wide) form in DARM around 4900 Hz. This peak moves up in frequency as the lock is maintained.

I have the online simulation of the HOM spacing (frequency vs time) shown in the top plot. As the anmation steps forward in time, we can start to find the maxima of the broad peak in DARM. I've taken the location of these maxima and plotted them in the FREQ vs TIME plot (I've only picked the location of the maximum value of the broad peak and tried to exclude all times before the lock is acquired and the frequency starts to change). The transient behaviour is quite consistent with what the simulation predicts. 

The two figures correspond to two recent locks but different ETMY ring heater settings:

1. GPS TIME: 1160974817: ETMY RH = 0W
2. GPS TIME: 1161055457: ETMY RH = 1.1W (aLOG 30685)

After the ETMY ring heater is turned on and stabilizes, we expect the HOM frequency to shift down by about 60Hz, according to the simulation. We see a commensurate change in the location of the peak in DARM.

If this is the TEM10 mode in the arm, then what is ringing it up?

Time 2:

More to come ...

(Download and run the MATLAB file to see the animation).

model restarts logged for Thu 20/Oct/2016 No restarts reported

model restarts logged for Wed 19/Oct/2016
2016_10_19 09:33 h1fw0
2016_10_19 10:13 h1fw0
2016_10_19 10:22 h1fw0
2016_10_19 10:59 h1fw0

Unexpected fw0 restarts, logs indicate slow file system access problems. Power cycled h1ldasgw0 (not shown) and h1fw0. No subsequent restarts as of time of this alog (49+ hours).

Made a small modification to a pre-modecleaner servo that reduced the boost gain by
lowering its corner frequency.  Installed the servo and couldn't lock the pre-modecleaner.
After about ~15 minutes of trying, I gave up.  The original pre-modecleaner servo was
re-installed.  With it I noticed on the CCD camera that the alignment had shifted.
Re-aligned the beam into the pre-modecleaner, checked alignment onto the locking
photodiode, re-locked the pre-modecleaner.

Bake of RGA is going good thus far, still "inching" toward 180C < temperatures < 200C everywhere excepting the tapering-off to 90C at turbo inlet.

Lock loss at NLN, same as last night, DHARD pitch went into oscillation. Since Terra only needed high power and not NLN, stopped there for subsequent locks.

07:10 UTC Sheila to LVEA to check PSL enclosure air conditioning
07:15 UTC Sheila back
07:28 UTC Attempting to lock
08:00 UTC Stopping at INCREASE_POWER (50W) for Kiwamu and Sheila
08:26 UTC Moving to NLN
08:32 UTC NLN
08:36 UTC Lock loss
08:53 UTC PRMI to DRMI transition worked
09:06 UTC Lock loss almost immediately upon reaching DC_READOUT
09:12 UTC I'm trying to turn off the ISS autolock, but something keeps turning it back on.
09:41 UTC DC_READOUT. Waiting for roll modes to damp.
09:49 UTC Moving on
10:01 UTC NLN
10:05 UTC Lock loss. DHARD oscillation before hand.
10:10 UTC Turning off ISS autolock turns on the first loop integrator? Turning on the ISS autolock turns off the first loop integrator?
10:30 UTC Stopping at INCREASE_POWER (50W). Terra taking PI measurements.
11:00 UTC Lock loss (PI mode 27)
11:21 UTC Stopping at INCREASE_POWER (50W). Terra taking PI measurements.
12:10 UTC Lock loss (PI mode 27)
12:14 UTC IR not found for diff. Found by hand.
12:34 UTC Lock loss just after reaching DRMI_LOCKED.
13:00 UTC Stopping at INCREASE_POWER (50W). Terra taking PI measurements.
14:16 UTC Changed ITMY ring heater upper and lower requested power from 1.25 W to .25 W per Terra's request.
14:23 UTC ETMY violin mode 9 rang up. Terra changed the damping gain to damp it.
15:03 UTC Lock loss. Trouble locking PRMI. Catches but does not hold.

Summary: ETMY PI 18041 Hz - aliased down from 47495 Hz, Mode27 - is (more readily) dampable if the OMC DCPD is used as error signal.  ESDs provide adequade force if actuating on mode while it is < 4 orders of magnitude above OMC-PI_DCPD noise floor (~10^4 magnitude in OMC-PI_DCPD channel), ~2.5 orders of magnitude above QPD noise floor.  

- - -

Previously we had been unable to damp Mode27 (alog 29685) and turned off ETMY ring heater (alog 29702) to have less optical mode overlap with this 47495 Hz mechanical mode. Wednesday night I turned the ETMY ring heater back on to revert back to the bad zone and more thoroughly test our ESD damping capabilities. This mode has the highest gain during the transient time.

Over the past 20 hours and about 10 locks, I've found we have the actuation force to damp this mode if it is caught early ( < 4.5 orders of magnitude above noise floor in OMC signal ) which is much more likely when using the OMC DCPDs. All PI damping nominally uses error signal from TransMon QPDs. The OMC DCPDs also see mechanical modes and with an SNR ~15x the QPDs (see here for example from tonight of Mode27 seen in both error signal paths). We have avoided using DCPDs as error signal becaues the coupling path is not well understood and we see gain sign flips and much less steady phase changes. However, the high SNR seems necessary for PI with high gain that rings up quickly so that the damping loop can actuate against it more immediately while the mechanical mode amplitudes are still lower. This and other PI in the 47kHz ring up especially quickly (and twice) during the first hour transient sweep. Mode is very responsive and easily damped with a gain sign or phase change under 4 orders of mag above noise floor (1k magnitude in H1:OMC-PI_DCPD_64KHZ_AHF_DQ); above 4 is gets less responsive and is essentially non responsive by 5 (10k mag). So while we do have an error signal from QPDs within the effective damping range, the smaller window combined with high PI gain/rapid ring ups make the QPD signal inadequate. 

Operators: I've left Mode27 in the new OMC DCPD scheme. Patrick and I found a pattern of needing to change the gain sign twice during the beginning of the lock and adjust phase after that during the next hour or so. This mode responds very quickly, so be ready to immediately revert gain signs if it turns out to be the wrong direction. 

Note: Rang up with single quadrants (LL or UR) a few times and saw slightly less effective actuation than with LL+UR, though still need to process actual ring up time constants to compare effect. I switched once to LR, UL drive but many modes went crazy and broke lock so didn't try again tonight. Will repeat at lower power to get relative quadrant coupling for a given mode. 

NPRO pump diode output power and NPRO output power for the past 12 months.  The power decay for the pump diodes
has more or less levelled out.  We no longer really have any margin left for the pump diodes.  At this stage of
their life, increasing the diode current might precipitate their demise.

    The NPRO power may have levelled off too.  We should still plan on replacing the NPRO during the mid-run
break.

We had the 4735 Hz violin mode ring up bigly ~13:30 UTC. Was able to damp by flipping the sign; it's still fairly rung up so incoming operator should keep an eye. This is ETMY MODE 9.

Per Sheila's request, we just reduced ITMY ring heater 1.25 W --> 0.25 top, 1.25 --> 0.25 bottom at 14:16 UTC.

Keita, Sheila, Kiwamu

This afternoon Keita and I did another test of opening and closing DBB shutters, since Keita realized that there are multiple shutters that matter.  The results are in the screen shot.  We only see two shutters on the PSL layout, (SH01 in the 35 W path to the DBB and SH02 in the 200W path) and on the photos documenting the table, but there must be a third shutter, perhaps inside the DBB box. We did not test switching to the 35W beam because that caused a lockloss last night. Apparently the shutters used here are Thorlabs SH05, which has an aluminum blade according the the thorlabs website. 

When changing between shutter states today we saw a broad band change in the DARM noise throughout our 200Hz-1kHz lump, (this is a little different from what we saw last night).  However, we saw 3 different noise states in DARM depending on the shutter requests, shown in the attachment.  

We guess that the shutter which is controlled by the epics channel "PSL-DBB_SHUTTER_DBB" is inside the DBB box itself and not on the layout.  It is hard to explain the table above.  For example, if no beam is selected, and both beams are really blocked before they reach the DBB, why would closing the shutter inside the DBB matter?  

Kiwmau and I went inside the PSL, placed beam dumps in the paths to the DBB.  We placed a "black hole" beam dump (no cone in the middle) in the HPO path (a 250 mW beam between M3 and M12 on the layout).  Looking at that beam with an IR card, we could see a corona around it, pictures will be attached to this alog.  This corona is scattered around, hitting the black baffle near the DBB apperature and other things.  We also placed a black glass beam dump upstream of the front end laser beam path the the DBB, just before the shutter. 

Update:

After waiting out the Japanese earthquake, we relocked.  The lump was smaller in the first moments of the lock.  After a few minutes the peaks reappeared, but the peaks still changed when we opened and closed the shutters, in a way that is repeatable although the plot is confusing since the overall level of noise was changing probably with the thermal state.  (each time we opened the shutter, things got worse than they had been).

We do not understand how changing the shutter state impacts the DARM noise, although we think we have ruled out scattered light.   Kiwamu thought that perhaps the change in the noise could be due to the change in the diffracted power when we move the shutter (see Keita's alog 30679). We tried a test of changing the diffracted power, which unlocked the IFO.  It could also be through the same electrical coupling that means the diffracted power changes when we open the shutter.