J. Kissel, A. Pele, B. Shapiro, J. Warner

In attempts to measure/calibrate the ETMY actuation function from each stage to the arm cavity with high precision (using the Red/Green beat-note when locked on Red), why tried again to get the Green/Red light locked in the arm cavity. However, we failed to get the arm locked. Queue sad trombone -- we lose the end station first thing Monday morning.

Why we think we failed:
- For some reason we couldn't figure out, ISI-ITMY would not isolate at either level 2 or level 3.
    In order to assist long term studies, we decided to isolate to level 2 tonight. ISI-ETMY and ISI-BS came up just fine.
    - Checked that CPS offsets were in the right place
    - Followed the detailed instructions (many times).
    - Trips on bringing up Stage 1 (on the actuators, since we disabled the inertial sensors during the turn on process).
    No dice. Both levels were functional and stable yesterday.

- Poor alignment of the IFO
    - After noodling around with SUS-BS, SUS-PR3, and SUS-TSMY and getting H1:ALS-Y_REFL_B_LF_OUT_DQ no lower than 11000, I realized that, though the ISI-ITMY offsets are small, the table may not be in exactly the right good place I had last night when both ISI-ETMY and ISI-ITMY isolated. After tweaking the ITM alignment, the REFL_B came down to 9000-10000. However, I could not get H1:ALS-C_COMM_A_DEMOD_RFMON to ever go above -29 dBm -- the most I could get was -30 dBm (though this was true last night as well). Further, at some point of the alignment of ITM, I was able to get the REFL_B signal to "bottom out," in that the characteristic 0.4 [Hz] QUAD motion would disappear. So... maybe I'm on the hairy edge of a diode some where?

Where/How it fails: at the end of the CARM_handoff script, and it blows the reference cavity (and subsequently the mode cleaner). 
- During some of the lock losses, the RefCav would take a few minutes to catch lock again, so I thought the IMC Gaurdian was fighting the RefCav, as Stefan / Rick / Kiwamu had diagnosed yesterday. So, I'd switched the IMC Gaurdian to manual for a bit, and the RefCav would come up fine ... but this may just be a red herring.
- Also, I remember Kiwamu / Alexa having trouble with getting past the stage of the CARM_handoff because of the issues with demod phase rotation of the IMC vs. input polarity of the IMC Common Mode Board.


So, we leave the HIFO-Y in a rather sorry state tonight. Note that the red light is still flashing in the arms; I'm not sure what effect this has on the green cavity performance.

Cavities Locked: Input Mode Cleaner, Arm on Green 
Chamber    HEPI                                   ISI                               SUS
HAM1       Locked                                 n/a                               n/a
HAM2       Floating, Alignment Offsets Only       Level 2 Isolated                  MC1, MC3, PRM damped Level 1.5; PR3 damped Level 1.0
HAM3       Floating, Alignment Offsets Only       Level 2 Isolated (eLIGO Blends)   MC2, PR2 damped Level 1.5 
BS         Level 2 Isolated (Position Locked)     Level 2 Isolated                  BS damped Level 2.0
ITMY       Locked                                 Damping Only                      ITMY damped Level 2.1
ETMY       Level 2 Isolated (Position Locked)     Level 2 Isolated                  ETMY damped Level 2.1, TMSY damped Level 2.0


Tonight's BSC-ISI Level 2 is brought to you by:
Blends at ST1 "750mHz" and ST2 "250mHz"
GND to ST1 STS2 Sensor Correction is OFF
ST1 to ST2 T240 Sensor Correction is OFF
ST0 to ST1 HEPI L4C Feed-Forward is ON (with "FF01_2" filters)
The Input Gains for the L4Cs and GS13s are OFF (I *think* this means they're in low -gain mode). They're ON for the T240s.

These are measurements of the loop gain transfer function of the IMC cavity loops running on MC2. The first pdf shows the loop gain transfer function on M2, the second is the loop gain transfer function on M3. Note the good agreement with the model.

The UGF of M2 is about 3.2 Hz
The UGF of M3 is about 6.5 Hz

The data for the M2 plot live in
/sus/trunk/HSTS/H1/MC2/Common/Data/2013-07-26_H1IMC_M2-M3_Crossover_OLGTF_TF_Export
The data for the M3 plot live in
/sus/trunk/HSTS/H1/MC2/Common/Data/2013-07-26_H1IMC_MCL-MCF_Crossover_OLGTF_TF_Export

The matlab function that makes these plots is
/ligo/svncommon/SusSVN/sus/trunk/HSTS/Common/FilterDesign/IMCmodel_H1_MC2_M2M3hierarchicalfeedback_26July2013.m

Work on OSB Optics Lab – Andres Medinas
Testing HLTS PR3 (Transfer Functions) – Arnaud
Work on LVEA (by the beam splitter) – Richard
Doing Testing on the IMC (Running TFs) – Jeff K.
Taking equipments to End X – Justin
Finished TFs on IMC – Jeff K.

J. Kissel, B. Shapiro

We're trying to compare measurements of the input mode cleaner loop crossovers to a model, and got stuck because the userapps repository's copy of the H1LSC.txt filter file was out of date. We've copied over the latest version of the file from
/opt/rtcds/lho/h1/chans/H1LSC.txt
into the userapps repo here
/opt/rtcds/userapps/release/isc/h1/filterfiles/H1LSC.txt
and committed the new version. Note that there were many more differences between the chans version and the userapps version, most likely associated with all of the HIFO-Y work.

We really need to make the chans copy of every foton file a soft-link to the userapps repo version for every foton file. Currently, this is only true for the SUS, a few IOP, and the ISCEY filter file.

Also -- the LSC model is still running with an IMC block in its top level, so even though the channel names for the IMC filters are, for example H1:IMC-L, there is not foton file called "H1IMC.txt," as one would expect. Instead, its filters are buried in the H1LSC.txt file.

After a long morning, I was able to check out HAM6's sensors, re-gap a couple CPS's, float the ISI, adjust lockers and plug everything in. Surprisingly, no locker shim adjustments were needed (every aLIGO ISI has needed small adjustments) and all other adjustments went smoothly. No major issues, but the corner 2 and 3 GS-13's are swapped. I didn't check to see if the in-air cabling at the chamber is swapped, yet, but I'm pretty sure of the in-vac cables. I've attached power spectra for CPS's and GS-13's, as well as an MEDM snapshot.

After many iterations of testing to narrow down the problem.  It would appear the with the SAT AMP attached to the Coil driver was when the oscillation appeared in the OSEM readbacks.  Putting the Test box in place of the SAT AMP did not show the problem.  Odds are it was an oscillation on the power that caused a problem on the PD circuit.  After shutting off the Coil driver and re-installing all of the cables there is no oscillation.

Here is the current status of the aLIGO SEI work regarding the HAM chambers. Everything in red is a change from last week's status. Everything in green is available.

Thursday, 25 July 2013 - The Manifold Cryopump Baffle was installed in H1 End-X!!! (pic 7)

The baffle was lifted and positioned between the Spool and the Gate Valve. It was a tight fit; there were inches of clearance (pic 3). We were stopped once to move the cable trays on the top of the Spool for the Assembly Fixture to insert the Baffle (pic 1 & 2). The Baffle was inserted into the Spool with less than 1 inch clearance around the Baffle (pic 4) and it went in SMOOTH! There were 2 men in chamber. After a few trial attempts to attach the Flexure Rods, the L-Brackets were removed to facilitate the install. Once the Flexure Rods were attached, the Assembly Fixture was removed. One blade released as expected and the z- was set with the Spacing Bar. There was some twist which was corrected at the Flexures. Final measurements to the end of the Spool have the baffle position ~3.25" on the East side and ~3.5" on the West side. Baffle rest 0.5" spacing to the Compression Rings all around. The Copper Plates with o-rings were attached and spacing to magnets set. The cut-out around the Ion Pump (pic 5) looks really good.

The problem of attaching the Flexure Rods will be discussed to see if we can reduce the amount of effort needed for future installs (pic 6).

All photos are available in Resource Space - https://ligoimages.mit.edu/?c=1346&k=434c8ef92c
(Resource Space has pictures of the life of the baffle starting at oxidation, to assembly, ending with installation, but not in any order.)

Many thanks to those who participated in this effort -
Apollo's Bubba, Mark, Randy, Scott & Tyler, Doug Cook, Joe DeRenzis, Jodi Fauver, Gerardo Moreno, Mitchell Robinson, Scott Shankle, Mike Smith, Chris Soike, Calum Torrie, Mike Vargas, Thomas Vo, Nichole Washington, John Worden and the entire Hanford Family!

Looked at electronics for HAM6 Cap Position Sensors. Hugo and Jim reported signals were not stable. 
When only corner 1 and 2 were powered up, signals behaved as expected. When corner 3 was powered up, all signals became unstable, some jumping about -2000 counts every few seconds. Looked at electronics in CER but could not find any issues. Disconnected CPS field cables in CER and placed a dc voltage on all inputs. Looked at outputs and could not find any offsets or oscillations. Went out to the floor and disconnected the following:
All grounding cables
CPS sensors going to the satellite racks next to the chamber
timing sync cable
Communication cables going back to CER
power cables

Reconnected all cabling, and looked at looked at signals with Hugo. Everything was within range, and seems to be responding. We are suspecting we might have had a grounding issue. 7-25-2013

Curious as to why the BSC-ISIs had tripped last night, I used the awesome "plot last WD trip" feature on the ISI watchdog screens. They had tripped at the following times:
ETMY: Jul 26 2013 06:02:08 PDT (Jul 26 2013 13:02:08 UTC, 1058878944)
ITMY: Jul 26 2013 06:02:10 PDT (Jul 26 2013 13:02:10 UTC, 1058878946)
BS:   Jul 25 2013 18:52:17 PDT (Jul 26 2013 01:52:17 UTC, 1058838753)

The HAM-ISIs and all HEPIs survived the night.

J. Kissel, H. Paris, A. Pele, B. Shapiro

After spending all afternoon getting all the chambers up into their best (local) performance, I've used Stefan's instructions to lock the Y ARM on Red. So easy -- even I could do it! Thanks to all of those who've written scripts to automate the ALS and IMC :-). Interestingly, and I forgot to ask about it, but there's no need to run any down script when the lock is lost. One just runs the two scripts again (assuming your Beam Splitter alignment remains good).

OK, I wrote the aLOG too soon. There have been several lock stretches, and the ISI-BS has tripped. I detailed time line is written below, for as long as I stayed here.

Here's the configuration of the SEI/SUS during these stretched:

Cavity Lock: 
Chamber    HEPI                                   ISI                               SUS
HAM1       Locked                                 n/a                               n/a
HAM2       Floating, Alignment Offsets Only       Level 2 Isolated                  MC1, MC3, PRM damped Level 1.5; PR3 damped Level 1.0
HAM3       Floating, Alignment Offsets Only       Level 2 Isolated (eLIGO Blends)   MC2, PR2 damped Level 1.5 
BS         Level 2 Isolated (Position Locked)     Level 3 Isolated*                 BS damped Level 2.0
ITMY       Locked                                 Level 3 Isolated                  ITMY damped Level 2.1
ETMY       Level 2 Isolated (Position Locked)     Level 3 Isolated                  ETMY damped Level 2.1, TMSY damped Level 2.0

* I noticed ISI-BS had tripped around 2:53 UTC, but it may have been down for some time. I didn't bother bringing it back up, 'cause I didn't want to blow the cavity lock. Or another three hours.

All Optical Levers are well centered.

All BSC-ISIs have been brought up to the configuration outlined in LHO aLOG 7226, but just for posterity, this means:
Level 3 Isolation Filters
Blends at ST1 "T250mHz" and ST2 "250mHz"
GND to ST1 STS2 Sensor Correction is ON (The corner station ISIs are both using the beer-garden STS2)
ST1 to ST2 T240 Sensor Correction is ON
ST0 to ST1 HEPI L4C Feed-Forward is ON (with "FF01_2" filters)
The Input Gains for the L4Cs and GS13s are OFF (I *think* this means they're in low -gain mode). They're ON for the T240s.

----------
Time Line (all times UTC, Jul 25 2013)
2:27 Locked on Red
2:46 Lost Red Lock
2:47 Regained Red Lock
    2:50 Glitch in CARM_IN1!
    2:53 Noticed ISI-BS had tripped. All other ISIs are still fully operational
    2:57 Glitch in CARM_IN1!
3:00 Lost Red Lock
3:06 Regained Red Lock
    3:11:23 Glitch in CARM_IN1! 
    3:24:47 Glitch in CARM_IN1!
3:27 We begin to ignore the IFO and go home, be cause there's enough data in the can to get a 0.01 [Hz] measurement in the past (assuming those glitches don't spoil the spectra)... but may the lock last through the night!

[Richard Dave Jeff Brett Arnaud]

Following aLog 7055

Today and yesterday we tried to understand why the beamsplitter suspension looks to be moving so much. In order to see higher frequency contents, we took a spectra with this time, test points channels (sampled at 16kHz). A large peak appears at 1900Hz for M1 top mass osem (2nd plot of the attached pdf) and M2 middle mass osem (3rd plot), as we saw few weeks ago on the TMSY after the power outage (see aLog 6338). The first and last plots are showing respectively the BS ISI motion (X and Y direction projected at the suspension point calibrated in um) and etmy suspension osem top mass signals, and none of them are showing such a feature.

To solve this, we tried fruitlessly several things

- power recycled IO chassis and front end h1susb123

- unplugged/replugged cables between satellite box/coil driver/AA chassis

to be continued [...]

While trying to get he ISI-BS up and running (to either Level 2 or Level 3) we saw instabillity whenever turning the isolation loops on, and has been so for most of the week.

Judging by the high DC content of the supersensor signals coming out of the Blend filters, we deduced that there was some offset that was (not?) accidentally applied.

The CPS typically have some level of bias voltage, we compensate for this with a digital offset, so the error point of isolation loops -- which are DC coupled -- is small. Those offsets used to be set in the local basis. We are preparing (see E1300548) to roll off a new update to set those offsets in the cartesian basis. The latter way allows to keep track of the platform's alignement over time, in the basis of interest.

Looking more into the ISI-BS screens, we found that offsets were set in the "current" block of the blend filters. Those offsets are the equivalent of the upcoming update's "cartesian biases", and were probably set there to get the benefits of the update earlier. However, some BURT restore had left the local basis offsets on as well.

Having both offsets on at the same time, created a huge DC offset at the input of the isolation loops, which the actuators had a very difficult time pushing to zero, and eventually causing the (or many) watchdog(s) to trip, usually very early in the ST1 turn on process.

Local CPS biases were turned off. It was then possible to turn on Level 3 isolation loops on ISI-BS. 

One can still determine the alignment of the ISI by looking at the input to the CPS input to the blend filters.

(Jeff, Kiwamu, Stefan)

With the H1:LSC-REFLAIR_A_RF9_I calibrated in Hz, and the open loop transfer function measured, here is the noise it sees: Input Mode Cleaner transmitted frequency noise.
Also plotted is dark noise (shutter closed).

We do not know yet what the ugly noise ~1/f^3 noise is.