Daniel, Sheila, Keita

This morning Peter King realinged the PMC again. The attached plot shows the PMC HV mon recorded yesterday afternoon, and now after the alingment, the peaks have gone down by about a factor of 3, and the noise in the ISS first loop out of loop PD also decreased.  We can further reduce the peaks in the HV mon by increasing the loop gain to 27dB.  We saw the loop start to oscillate with a gain of 30dB, which might explain the braodband noise in DARM we saw when we went to 30dB the other night. (30682)

In the attached plot, LSC-EXTRA_AI_1, which is calibrated into volts at the ADC.  There is a SR560 with a 10 Hz high pass and a gain of 100 between the monitor point and the AI input, so combined with the 1/50 gain of the monitor, 1 V here is 2 Volts applied to the PZT.  The PZT is a custom made PZT, PI PAHH-0013, the capacitance is 63nF, travels 4um/kV.  We have a 3.3k resistor, so the pole is about 770 Hz.  So to calibrate this channel into meters:  V LSC_EXTRA *2(Volts to PZT/Volts LSC_Extra)*4um/kV= 8e3pm/Volt, with a pole at 770 Hz. 

The measurement from yesterday was made in full lock, with the ISS second loop at full bandwidth (PDB is out of loop).  This morning's measurements were made without the ISS second loop on. 

after being stable since 11am Wednesday, h1fw0 restarted itself at 16:24 PDT Friday afternoon. This did not look quite like a slow-disk error, but I decided to do a pre-emptive power cycle of the h1ldasgw0 solaris computer before the weekend break. Sequence was:

• h1fw0: stop monit
• h1fw0: stop daqd
• h1fw0: umount /ldas-h1-frames
• h1fw0: power off
• h1ldasgw0: power off
• h1ldasgw0: power on, wait about 10 mins
• h1ldasgw0: mount /ldas-h1-frames
• h1ldasgw0: source /etc/dfs/dsftab.qfs
• h1fw0: power off, wait for everything to auto start

460 day trend shows IM3 moved in yaw and what looks like a corresponding move by IM4 yaw of about 50urad.

IM4's yaw history:

• July 2015, about -610urad
• Aug-Nov 2015, about -590urad
• a brief stint at -575
• Nov 2015 to Sept 2016 a climb from -630 to -610
• Sept 2016, a move to -540urad, a change of 50urad, that could be in response to the move of IM3

[JimW, Jenne]

We were really struggling to lock PRMI.  When it would catch for a second or two, we could see on dataviewer somewhat slow oscillations before it would lose lock.  This indicated that maybe the gain was too low.  So, we put a factor of 2 more gain, and it seems to be okay so far.  

- 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.

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.