Richard warned me that the Fiber polarization had probably drifted at EY due to some work done around the table. Indeed it had drifted to up to 33% for the wrong polarization. However, Stefan had increased the threshold to 36. I returned the threshold down to 30 and adjusted the controller. I also had to adjust the EX polarization when I turned the controller on, which forced both polarizations to drift. All is good now.

Craning activity in the LVEA at the moment. A cleanroom is being moved - Apollo

model restarts logged for Wed 14/May/2014
2014_05_14 12:37 h1fw1

unexpected restart of h1fw1

Kiwamu, Stefan,

Both ALS_DIFF and ALS_COMM were straight forward today, and we got them locked literally in minutes. I.e. the ESD is still working fine.

We misaligned the arms, and verified that 3f locking works just fine without the arms.

We locked the arms and parked them 1kHz off resonance. I this configuration the the RF27_I signal worked fine, but the REFL27_Q signal had significant contamination from the COMM noise at 70Hzish (periscope peak). Thus we designed a broad notch filter in the mich loop, which kept the BS from saturating.

However it seems that MICH is still too strongly contaminated by the low frequency COMM noise. As a result the MICH loop seems to drift out of its linear range.

Ideas:
 - divide REFL27_Q by POP_18 to expand the linear range
 - rephrase REFL27 to reduce the coupling

Either way, an earthquake told us to get some sleep.

David H, Greg G, Thomas V

- Corner Hartmann table now has the Y-arm in-air optics mounted and positioned, ready for alignment using the visible laser. Components for the HWS were tracked down and staged.
- TCSX CO2 laser continued to run all day. Once going to laser hazard we realigned the CO2 beam that is transmitted through the output beam splitter. This transmitted beam passes through another 50/50 beam splitter, with the (second) transmitted beam aligned to the output power meter, while the reflected beam was expanded and aligned to the FLIR camera screen position. This required the repositioning of some cables and mounts located near the CO2 laser and RF driver.  

TSCX laser will continue to run overnight. Rotation stage set to 44 degrees (with interlock cable removed to prevent changes to this angle). Table doors are locked. 
TSCY chiller and power supplies continue to run, TCSY laser is turned off.

Richard showed me that there is a liner coupling from any of the electrodes to the OPLEV even when there's no bias anywhere, and the bias-less coupling is on the same order as the coupling with bias.

I started flipping the bias of the common ("DC") electrode while keeping all four quadrants at zero count output, and indeed there's a linear coupling, and the effect is not subtle.

In the attached, I changed the DC bias from 125000 to 0 to -125000, then to 0 and finally back to +125000. The ETM points up by 0.3urad in the first step, then further up 0.5urad in the second step (instead of going back to the original position). It's 0.8 urad peak to peak!

OTOH, when I set the four quadrants such that top two outputs -50900 counts and the bottom +50900 to tilt the optic legitimately while the DC bias is kept at 125000 counts, I can only move it by -0.5 urad peak to peak (second attachment).

This could still be electronics offset, so I looked at the ESD readback. The readback is not calibrated, but four quadrants always read from -75 to -200 counts when I'm outputing zero, the 300volt-ish thing reads 30000-ish counts, so the voltage offset for the quadrants should be 2V-ish at most. That's not large enough, I think.

J. Kissel, for F. Clara, and R. McCarthy

After investigating further, Richard and Filiberto found that source of failure in the chassis was the mysterious loss of the +18 V power supply to the ESD driver chassis between rack power strip and the the back of the chassis. This was confirmed after disconnecting, to find the positive leg without continuity. However, after "pulling the cable apart" to find the source of the discontinuity, he was not able to reproduce it. After reassembling the cable, and restoring the connection, the driver came alive again. Further vigorous attempts to recreate the disconnect were unsuccessful. It appears the gremlins inside the driver chassis are creeping there way out to the power supply.

This 18V power cable came with the ESD driver from Strathclyde, so Richard plans to replace it with one commercially made in house.

As soon as I get the arm from fellow commissioners trying to finish gathering data for her thesis, I'll try to grab the data I'd originally set out to get this morning.

While working on EX suspension, I realized the yaw motion was big on the oplev, so I tried switching the Rz blends on the ISI to see what's a good config. Moving the Rz blends of both stages from Tcrappy to Start seem to have helped (~0.6urad peak to peak -> ~0.2urad). Green curve in attached plot is the oplev yaw signal (urad)

Day's Activities

• 6:30am ETMy measurement ran (was done early morning)
• MY low pressure sensor still valved off causing alarm
• SRM Install work begins (Jeff, Andres, Betsy)
• 9:10am Pulling cable at end stations (Aaron)
• 9:15am David/Greg working on Hartman table
• Kyle will be doing Vacuum system work today
• 9:20-11:44am SRM Alignment set-up (Jason)
• 10:05am Travis/Mitch ACB work
• ~10am Dust Monitor #5 went to a few thousand counts (but didn't receive an alarm for it)
• 11:20am Richard/Fil heading to EY for ESD work
• KEPR film crew on-site.  (will broadcast at 5 & 6pm)
• afternoon--EX ESD work (Richard/Kissel)---swapping out chasis
• High dust counts in the Beer Garden (Jeff investigated)
• ISS PD Array in the H2 Laser Enclosure Room (they will be going to Laser Hazard in their room)
• Since EX & EY are closed up, I increased the Dust Monitor Alarm levels to 500counts (MIN) & 1000counts (MAJ)
• Transitioning to Laser HAZARD after Safety Meeting

J. Kissel, for K. Izumi, S. Ballmer, and S. Dwyer

One of the tricks to get ALS DIFF working without saturation was to tweak the distribution filter design. I attach a comparison between the filters installed on 2014-05-08 vs. those tweaked last night (2014-05-14). Only two small changes: 
(1) To the UIM-TST LP, whose composition included 
    (a) two poles at 6 [Hz], three poles at 150 [Hz] 
    (b) elliptic filter of (freq,order,ripple,stopDB,zQ) = (9, 3, 1, 20, 1.4)
    (c) elliptic filter of (freq,order,ripple,stopDB,zQ) = (19, 3, 1, 20, 1.4),
now has the second elliptic filter's corner frequency much lower, at 6 [Hz], i.e. a new (c) of 
    (c) elliptic filter of (freq,order,ripple,stopDB,zQ) = (6, 3, 1, 20, 1.4),

(2) To the TST-UIM HP, whose composition included
    (a) (1 - UIM-TST LP) 
    (b) an elliptic high-pass of (freq,order,ripple,stopDB,zQ) = (.7, 2, 1, 10, 3)
now has an additional high-pass filter,
    (c) two zeros at 0 [Hz], two poles at 0.2 [Hz], normalized to unity at high frequency, i.e. zpk([0;0],[0.2;0.2],1,"n")gain(25)
Note that this extra low-pass has been installed, ignoring its affect on the complementarity with the UIM-TST LP. This needs to be fixed if we desire complementarity.

These tweaks served to (1) to move the elliptic filter's gain peaking bump out of the way of the 10 [Hz] features in the input noise, and (2) roll off the low-frequency end of the test mass drive faster.

-------------
Details 
The New H1 SUS ETMX Filter Configuration:

H1:SUS-ETMX_M0_LOCK_L (same as before)
FM1 "invL2L1" (part one of plant inversion filter)
FM2 "invL2L2" (part two of plant inversion filter)
FM3 "top/tst" (gain only filter to compensate for the gain ratio)

FM5 "blendLP"

H1:SUS-ETMX_L1_LOCK_L 
FM6 "invL2LNEW" (part one of plant inversion filter)
FM7 "patch" (part two of plant inversion filter)
FM8 "LISOfit" (part three of plant inversion filter)
FM9 "uim/tst" (gain only filter to compensate for the gain ratio)

FM3 "blendHP" (UIM-TOP HP complement)
FM4 "blendLP-2" (UIM-TST LP complement, with lower frequency elliptic filter)

H1:SUS-ETMX_L3_LOCK_L
FM6 "MatchedinvL2L" (part one of plant inversion filter)
FM7 "patch" (part two of plant inversion filter)

FM4 "blendHP-M0" (TST-TOP HP complement)
FM5 "blendHP-L1_2" (TST-UIM HP complement)
FM9 "hp.2" (extra high-pass for TST-UIM HP complement)


In order to create these modifications to the UIM-TST LP, Kiwamu grabbed my design script from 
/ligo/svncommon/SusSVN/sus/trunk/QUAD/Common/FilterDesign/HierarchicalControl/DARMmodel_ALS_20140428.m
copied it to his home directory, 
/ligo/home/kiwamu.izumi/
to play around,
/ligo/home/kiwamu.izumi/Desktop/farm/matlab/
modified the filters mentioned above, and then used a fancy new script,
/ligo/home/kiwamu.izumi/Desktop/farm/matlab/fofon.m
which takes in a continuous zpk filter, and produces a foton design string to be copied and pasted into Foton. If the filter is a high-pass, the only other step is to use the "Gain" field to set the gain to be unity at high-frequency.

The modification to the TST-UIM HP was done later in the evening after I'd left, but by the simplicity of its design, I think it was just added directly without testing any stability or complementarity in Matlab prior to install. 

[[elliptic filters are generated using ${SeiSVN}/seismic/Common/MatlabTools/myellip_z2.m]]
[[hp elliptic filter is generated by ${SeiSVN}/seismic/Common/MatlabTools/myhpellip_z.m]]

Andres R., Margot P., & Jeff B.

   We installed H1-SRM into HAM5 today. The installation went smoothly. Will start on alignment work in the morning.  

Betsy, Mitchell, Margot, Myself

Today we finished assembly of the ACB suspension and mounted both the suspension and the baffle box to the test stand.  We will continue adding the last few remaining bits to the assembly and proceed with suspending and balancing tomorrow.

Because of physical restriction on the TMS ISC table real estate, pico mirrors for IR QPDs (M4 and M14) are mostly degenerate, i.e. if you rotate one mirror the beam position on both of the QPDs change by similar amount in the same direction.

Using nominal QPD sled parameters and as-built TMSY parameters (that is not that different from TMSX),

QPDA position shift = [3.2105,    3.1256] * [M4 rotation, M14 rotation]'
QPDB position shift = [4.8555,    4.9264] * [M4 rotation, M14 rotation]'

where [A B]' means a column vector. As you can see this is mostly degenerate.

For example, to keep the beam position on QPDA fixed while moving QPDB position down by 1mm, you PIT down M14 by about 5.0 mrad and then PIT up M4 by about 4.9mrad:

QPD diameter is 3mm, so as far as we see the beam on one QPD when the other is centered and the beam is not close to the edge of the clear aperture for viewport-TMS path, it should be possible to center both without losing the beam on ISCT.

I think that's the case for Y, but it's not clear if that was the case for X at some stage.

Since both end stations are closed up, I increased the alarm levels for both of these monitors to 600cts (MINOR) & 800cts (MAJOR) for 0.3 & 0.5um (they had been set at 100 & 200 cts, respectively).

J. Kissel, K. Kawabe, R. McCarthy, A. Pele

At ~11:30a PDT (~18:30 UTC) I began trying to drive the H1 SUS ETMX ESD in Pitch, to replicate a driven, optical lever ASD (e.g. LLO aLOG 12512). To my dismay, I found no coherence. We performed several other excitation tests, including repeating Keita's measurement from yesterday (LHO aLOG 11872), also to no avail. Finally, after obtaining Richard who was valiantly battling the ESD at EY, he told us to check out the monitor read-backs, 
H1:IOP-SUS_EX_MADC1_EPICS_CH0 - 5
which can be found from the A1 (the second ADC ) screen off of the H1SUSEX IOP GDS_TP screen. These channels showed values frozen at ~2050 [ct], which (though spurious) would correspond to a voltage of 
2050 [ct_ADC] * 40/2^16 [V_MON/ct_ADC] * 40 [V_ESD/V_MON] =  50 [V_ESD]
Richard immediately recognized these values as indicative of a failure of the driver.

I started my drive at 18:32 UTC (11:32 PDT), and the bias channel falls from ~30000 [ct] (ADC), to 2050 [ct] at 18:20 UTC (11:20 PDT).

There was activity in the XVEA (between 9:30a PDT - 11:30a PDT), around the racks that the ESD driver is installed, but it was with seemingly unrelated network cabling. So it appears as though the failure was a result of some closeout activity.

However, when Richard and I drove down to investigate,we found that even the driver's +/-18V LEDs were off. After a quick investigation, including a full high-voltage power cycle, with limited tools, Richard concluded that the ESD Driver needs to be swapped with its spare, and is doing so now with Fil. 

Welp -- we got *one* promising night of ALS DIFF locking under 1 [nm] rms...

We looked at a spectrum of the Optical levers while we were locking DIFF with low bandwidth. The ETMY pitch was 2 orders of magnitude above all the others, so we switched this back to the legacy decoupling fitlers, and the excess noise went away.  The dashed lines in the attached screenshot are with the new filters, solid lines with the legacy filters for ETMY UIML2P only. 

Some other things that we noticed tonight:

on the ops overview screen the ETMY suspension watchdog can be green even when ETMY is tripped.

We also have had several times that the mode cleaner locks on a wrong mode, where the transmitted counts are low.  In this case we need to unlock it manually, maybe we need to check some thresholds in the guardian. 

I think that the ISI trip happened before the suspension trip, this was while we were locking diff.  I also thought that the T240s were green before I untripped the watchdog, but maybe they weren't because the ISI tripped again as it was isolating. 

Added a ZFL-500HLN amplifier to the ALS DIFF RF path.