We resumed analysis of MC3 Phase 2a data taken Sept 27 and found that now the sus ails from pretty severe yaw to vertical and transverse coupling.  Travis eye-balled the suspesnion and sees that it is not well aligned in Yaw.  Note, the alignment procedure during the build phase of HXTSes is all done "by eye".  I think we possibly have been aligning suspensions to the crocked side flag mount (a recent discovery).

Note to self, our recent issues with processing the plothsts_dtttfs.m script was due to file naming convention.  Watch for dash and underscore locations in the name!

A couple of incorrect sign conventions were identified in the EUL2OSEM and OSEM2EUL matrices. This affects the Transverse -> SD OSEM coupling elements and Vertical -> T1T2T3 OSEM coupling elements. These elements incorrectly possessed a positive (+) rather than negative (-) sign.

This was previously corrected for at LLO (see LLO aLOG entry 4023), and has now been corrected at LHO, using a similar method.

The following H1 suspensions had their matrix elements rectified: MC1, MC2, MC3, and PR2.

Safe BURT snapshots were taken of each of the above suspensions.

The above safe snapshots were then committed to the svn.

N.B. This change should be checked for future H1 suspensions too, i.e. PRM and SR2, since HLTS's are unaffected.

I consulted with Patrick, and the dust monitor at EY that was alarming this morning had alarm levels that are used for sampling inside a clean room.  The dust monitor may still be in the clean room, but the clean room is off, so I set the alarm levels to the nominal "outside" a cleanroom numbers.  This change is to EY dust monitor 1.

In cleanroom: for both 0.5u and 0.3u 
Minor = 100.0
Major = 200.0

Outside cleanroom:

for 0.5u:
Minor = 20000.0
Major = 100000.0

for 0.3u:
Minor = 10000.0
Major = 50000.0

The 9/27 ISI move and BS suspension takedown (partial) photo collections now sit in ResourceSpace. 

I installed the HAM-ISI control loops level-2 on HAM2-ISI. To do so, I had to implement the notches I already added to the level-1 loops. I also added a couple other notches to respect the gain margin requirements.
Simulation Plots

Switching from level-1 to level-2 with the MEMD command window worked well, without tripping the ISI watchdogs.

I took sprectra on HAM2-ISI with those loops on. I compared those spectra with the ones measured yesterday, in the following configuration:
  - no active control
  - Damping only
  - Cotrol level-1 with boost and notches

Data is under the SVN. Spectra are attached.

[Stuart A, Jeff B and Andres R]

The following OSEMs have been installed into the SR2 (HSTS) suspension, as well as entering gains and offsets into the OSEM INPUT filters:-

BOSEMs
M1-T1, s/n = 076, open-light = 26125.3, offset = -13063, gain = 1.148
M1-T2, s/n = 423, open-light = 27116.1, offset = -13558, gain = 1.106
M1-T3, s/n = 646, open-light = 25764.8, offset = -12882, gain = 1.164 (c)
M1-LF, s/n = 150, open-light = 31458.2, offset = -15729, gain = 0.954
M1-RT, s/n = 098, open-light = 25390.6, offset = -12695, gain = 1.182
M1-SD, s/n = 668, open-light = 25655.6, offset = -12828, gain = 1.169 (c)

AOSEMs
M2-UL, s/n = 232, open-light = 26261.4, offset = -13131, gain = 1.142
M2-LL, s/n = 213, open-light = 27884.6, offset = -13942, gain = 1.076
M2-UR, s/n = 279, open-light = 25761.6, offset = -12881, gain = 1.165
M2-LR, s/n = 366, open-light = 26451.8, offset = -13226, gain = 1.134

AOSEMs
M3-UL, s/n = 312, open-light = 26656.6, offset = -13328, gain = 1.125
M3-LL, s/n = 424, open-light = 25976.2, offset = -12988, gain = 1.155
M3-UR, s/n = 285, open-light = 25678.3, offset = -12839, gain = 1.168
M3-LR, s/n = 304, open-light = 25379.6, offset = -12690, gain = 1.182

Stemming from an incorrect ICS entry regarding BOSEM #646's characterisation status, SR2 currently has two characterised BOSEMs installed on M1. The M1-T3 BOSEM will be swapped out at the earliest convenience.    

It should also be noted that the M1-SD BOSEM has been re-located to the opposition side of the structure, as requested by systems, and already implemented at LLO. The change of sign then had to be accounted for in the COIL OUTPUT filters (by flipping gain sign from -1 to +1).

Firstly, a set of M1-M1 TFs were taken, with damping loops OFF, for all DOFs (see 2012-10-01_0900_X1SUSSR2_M1_ALL_TFs.pdf), which show good agreement with the model. These TFs were then repeated, but with damping loops ON.  

Secondly, both damped and undamped TFs obtained have been compared to all other LHO HSTSs tested at Phase 1b (see allhstss_2012_10_01_Phase1b_SR2_ALL_ZOOMED_TFs.pdf). 

Thirdly, power spectra have been taken with damping loops both ON and OFF for each stage (see 2012-10-01_1700_X1SUSSR2_M*_ALL_Spectra.pdf).

Power spectra data, with both damping ON and OFF can then be compared to a similar HSTS, PRM, during Phase 1b testing (see allhstss_2012-10-01_X1_SR2_Phase1b_ALL_Spectra_Don.pdf and allhstss_2012-10-01_X1_SR2_Phase1b_ALL_Spectra_Doff.pdf).

In addition, power spectra for specific degrees of freedom (L, P and Y) can be more conveniently compared across multiple stages (M1, M2 and M3) of the same suspension in the final plot found below (see allhstss_2012-10-01_X1_SR2_Phase1b_X1SUSSR2_M1M2M3_Spectra_ALL_Don.pdf).

Finally, all data, plots and scripts have been committed to the SUS svn as of this entry.

This should now be sufficient to complete Phase 1b testing of the SR2 suspension.

Tim N., Gerardo M., Bob A., Thomas V.

Today we assembled the support table (D1101953) with lab jacks and brought down the box portion of the Arm Cavity Baffle.  Since we were waiting for a few tooling parts to be baked (they did not fit in the bake oven on Friday), we will assemble the installation lift stand (D1101957) tomorrow in order to bring down the suspension portion of the ACB.  

Both the suspension and the box portion will be laid down in the tube while the cartridge is being removed, then the suspension and box will be extracted afterwards.   

HAM2-ISI features an unusual high Q resonance at 96.1Hz. This resonance is due to the top payload mass that still needs better boundary conditions with the ISI (see aLog comment #4025).

The seismic team uses generic controllers for the first level of the HAM-ISI controls.  The watchdogs of HAM2-ISI would trip on the actuators' signal when turning on those controllers. Indeed, the generic controllers did not account for such feature and the unusual resonance would consume most of the gain margin (Simulation Plots - No Notches), causing the controllers to amplify motion at 96.1Hz (see p.4-9 of the attached pdf), and thus to only be stable on their own (see p.2 of the attached pdf).

In order to get HAM2-ISI under active-control, we decided to apply temporary notches on the level-1 controllers of HAM2-ISI. We started with the most unstable controllers: X and RY.
Simulation Plots – Notches on X and RY

After implementing the new X and RY isolation loops, we were able to have all HAM2-ISI controllers running at the same time.  We took comparative spectra for the various configurations of the ISI: not damped, damped and controlled with the new controllers. They showed that the motion of the ISI was still amplified at 96.1Hz (Image #1).

In oder to correct that, we went through all the other controllers of HAM2-ISI and applied proper notches to them. The only one that did not need any was RZ.
Simulation Plots – Notches on all DOF
We then got rid of the excessive motion amplification at 96.1Hz (Image #2). 

HAM2-ISI is now under control Level 1 with the generic 900mHz blend filters ON.

Note 1: HAM2-ISI is loaded with dummy masses only. This control work was made in anticipation of the future Control & Commissioning of the unit, and in preparation of the Control & Commissioning that will soon be performed on HAM3-ISI.
Note 2: The iquiery described above involved looking into te details of the HAM-ISI generic routines, and revealed the need for minor corrections. Routine #7 was corrected twice: SVN revisions 6028 and 6077

IAS looked at the position of the Optical Table and gave us the deltas from perfect.  We looked at the Support Table level and found it level to +-0.1mm.  We did need to shift the payload on the Optical Table however, I had adjusted it to correct the overload I had found in aLOG 4242.  We leveled the Optical Table now to +-0.1mm at an elevation of -200.2mm global, 0.2mm low.
IAS gave us a correction for horizontal of 0.7mmN, 3.1mmE & 369urad cw but I decided not to do this.  We've already pulled the Support Table 5mm east and I'll likely already have to shift some HEPI piers around.  Our position spec for this table is +-3mm and tht was what we told ISC after they gave us a spec of +-6mm so I think we are OK.

Thanks to Scott & Ed

• Thomas, Gerardo, Tim working on arm cavity baffle

We finally swapped the M3 stage UL AOSEM which had a cracked filter (s/n 242).  The new unit (s/n 212) has an OLV of 26640.  Stuart reset the PR2 M3 UL OSEMINF offset to -13320 and the gain to 1.126.

As per Travis' alog yesterday, we indeed did hop into BSC8 this morning and finish checking and stowing the FMy and ITMy suspensions.  We put C3 socks on each.  Travis then started detaching the SUS cables at the internal feed-thrus.

Restarted h2 data concentrator to add h2isitst channels at 10:53 PDT.  The daqd process on h2nds0 failed to restart, so I started it manually.

On Friday, 28 Sep, the cleanroom was rolled to the north, then the solid stack was craned off the test stand and preserved clean. This morning, the test stand was wiped down. After lunch, the cleanroom was moved back over the test stand: the cleanroom/test stand and general area will be cleaned in preparation for the cartridge.

After some examination this morning, I was able to improvise both garbing and staging space in the iLIGO cleanroom atop the e-module. Jim Warner was instrumental in carrying out the plan. Apollo craned garbing/staging accoutrement to the e-module and things are close to ready.

- SEI work at input HAMs
- Ken at X-end
- Apollo installing ladder on mezzanine
- Vincent install a test model on the BSC8 Test Stand
- Cleaning of the optics table in Squeezer area

Both the ITMy and FMy suspensions in BSC8 have been fully locked down for transport, with the exception of the vibration absorber locker pins on FMy.  Optics caps are on both the ITM and TCP exposed faces and the inter-chain temporary transport stops (fingers) are in place.  On Monday, I will have Betsy take a second look and add any additional protection and C3 covers to the structure deemed necessary.  We should then be ready to proceed with ACB deinstall, decabling at the feedthrus, and SEI offloading of mass in prep for cartridge extraction. 

35W beam. Fans were on during these measurements.

B. Bland, J. Garcia, J. Kissel

Attached are plots comparing the recent H1 SUS PR2 Phase 2B measurements against other HSTS in various stages (completing the data package) in order to give a final answer on Phase 2B testing.

As of this entry H1 SUS PR2 passes Phase 2b and is go for install into HAM3, with the following caveats:
(1) Late in the game, the assembly team found an IR filter is missing on an M3 (Bottom) stage AOSEM. The spectra comparisons show that there's little-to-no difference in the response of sensor, i.e. it's functional (as far as you can tell in the noisy chamber-side environment). Regardless, the assembly team are aware of the problem, and will replace that AOSEM once in chamber, as there's plenty of room to play around in there, and it's a simple fix.

(2) It's a long story (so I'll save it for a subsequent comment to this log), but we discovered the same small T to Y cross-coupling at 1.1 and 2.05 Hz on PR2 as was recently discovered on X1 SUS MC3. At the time, (we thought) X1 SUS MC3 was the only SUS that had such cross coupling, and (we knew we) still had lots of chances to debug the issue before install, so we approved his Phase 1b results and agreed to move forward. However, due to the hectic/scattered measurements and turn-on blips of getting the HAM SUS up and running at LHO, the cross coupling in H1 SUS PR2 (formerly X1 SUS PR2) has fallen under the radar up to this point. So, in light of several things:
- (As in seen in the attached TF comparisons, specifically pg 2, the M1 to M1 T to T TFs), ONLY X1 SUS MC3 and H1 SUS PR2 show this particular cross coupling, out of Nine other HSTS that have been built project wide (again further clues, a better zoom, theories, and conjectures to come).
- We will move X1 SUS MC3 chamber-side, and the install team will spend an extended amount of time identifying/debugging the problem where there's plenty of room, and less pressure. Once the problem is solved, they will retroactively make the same changes to H1 SUS PR2 in chamber, where (at least in HAM3) there's a comfortable amount of room to make adjustments.
- Again, the coupling is small, and goes away with damping -- the concern is the model, which we use extensively to predict motion estimates, may not be as accurate.
 
Ease of later documentation, the individual measurements that compose the rest of the package are aLOGged here:
Damping Loops OPEN M1 to M1 TFs: LHO aLOG 3851
Damping Loops CLOSED M1 to M1 TFs: LHO aLOG 3855
Amplitude Spectra of All Stages: LHO aLOG 3861