H1 SR3 in chamber (HAM5 locked) undamped transfer functions for the three stages were measured yesterday night and are attached below. Overall they look good. Damped transfer functions are currently running.

Attachments in order :

1) M1-M1 undamped tfs compared with the model
Clean tfs, excellent match with the model.

2) M2-M2 undamped tfs compared with the model
Data is noisy, which is probably as good as we can get for now.
Pitch seems to couple with the first top mass vertical mode at 1.06Hz, yaw seems to couple with the second top mass roll mode @1.97Hz. Those coupling should be reduced with damping. 

3) M3-M3 undamped tfs compared with the model

Data is noisy, but gives a good idea of the tf shape. The only odd thing in the results was the factor of 4ish discrepancy between the model and the measurement for the pitch dof (meas=4ish*model). After spending some time trying to understand, it appeared to be a wrong euler to osem basis matrix. The pitch to osems factor (8.3) was 4ish times higher than the nominal value (2.4) (from make_sushlts_projections.m under HLTS/Common/MatlabTools/). Screenshot attached shows the corrected matrix.

I doubled check for PR3, which was also wrong. The new values were saved under a safe.snap for both suspensions and commited under the svn.

Not sure I saw this reported before. Today, I tried to align the y-arm. When I hit a certain angle in TMS, ETM or ITM, pitch or yaw, the lock would go bi-stable. When moving even further, it would stay at the lower value. However, the higher value could be regained by adjusting the PDH demodulator phase. As a matter of fact a phase change of ~20º can be used to switch between the states (see attached plot). Looking at the transmitted camera both modes look like 00.

Day's Activities

• SR3 measurement continues from last night (Arnaud)
• Running long term storage purge air (low pressure) over weekend (Greg)
• Hartman work begins (David H)
• Switched to Laser Hazard
• Looking for "leaky  valve"  (Ski)
• ISS went into oscillations at about 3am last night, switched from PD-A to PD-B
• Swapping out computers on the floor (cyrus)
• Diode Chiller low flow tripped PSL Watchdog
• Cyrus added memory to some of the video monitor computers.

This afternoon the following items tripped/went down: 

• PSL
• HAM2 ISI / HEPI
• HAM3 MC2 / PR2 / ISI / HEPI

After much head-scratching, ultimately pointed our focus to the PSL (the PSL was completely down, no light coming from the PSL, Gerardo noted an Error on the Diode Chiller).  Luckily Rick was here and was already on his way up to the OSB.  Justin & I accompanied him to the Chiller & Diode Room. 

[(1)Before heading to Diode Room, we turned the ISS AutoLocker OFF.  (2)When heading to Diode Room, Kissel took the IMC Guardian to DOWN]

In the Chiller room, we noticed an Error light and message on the Diode Chiller (the one on the top which has a clear spout on it); the water in the spout wasn't moving much--it's generally more turbulent.  We couldn't clear the error at the Chiller, so we garbed up & went into adjacent Diode Room.

Here we had the Beckhoff computer to work with.  On the System Status screen we saw the following Trips (in red):

• Interlock
• Diode Chiller Flow

We hit a RESET here, but the Diode Chiller Flow was still tripped.  We then went to the Chiller screen & clicked on the RED Chiller button to bring it back.  We also clicked on the red Watchdog button.  At this point we were GREEN, and done in the Diode Room.  On the Diode Chiller the Error light was OFF (but we still saw the Error message on the LCD screen).

When we walked back into the Control Room everything was good, green, & we had PSL light.  The ISS Diffracted Power Was a little low, so we clicked it more positive (i.e. made absolute value of voltage a coule hundredths smaller.].

[when we had PSL light, Kissel requested "LOCKED" for IMC Guardian]

Lisa

At Livingston they have to realign the arms very frequently in order to mantain high power build up. It seemed like we were not seeing the same problem here, but we didn't really have any numbers for Valera.

So, I left both arms locked on green last night. The plot shows a 6 hours trend of the green transmission power for both arms, and amplitudes of the beat notes. The guardian was left on, and it was automatically recovering lock.

The Y arm power dropped by ~10-15% over 6 hours. For whatever reason X was drifting much more than Y. Still, on a 1 hour timescale, you can't really see any significant drift; over 6 hours, the X arm drift was ~50%. I don't know if it has been already observed in the past that X drifts more than Y, or if it was just an isolated event.

I've upgraded the memory in all of the wall display computers in the control room from the woefully inadequate 2GB, up to 8GB.  This should make them run much better and prevent swapping and the general malaise that makes things quit working or otherwise grind to a halt on them after a while.

TCSY:
- continued with CO2 beam alignment... transmitted beam through the second beam splitter (1% pickoff) is now aligned to the two quad thermopile position sensors.
- temperature sensors run to the water cooled beam dump, AOM driver and cooling water manifold. Tested and appear to be operational. Once the clamps are received back from LLO these can be fixed in position.
- AOM driver power cable re-routed

TCSX:
- CO2 laser turned off at 2130 UTC
- chiller and power supplies for both TCSX and TCSY were turned off at 2135 UTC
- FLIR camera/screen cover removed. Camera front face to screen distance is 8" (rather than the 13" on the design). Photo attached. 

TCS install checklist was also updated.

After the PSL went down, MC2 IOP watchdogs tripped this afternoon, which cascaded to HAM2/HAM3 ISIs.

It tripped because of a large ISC length control offset signal applied on the left and right osems of the top mass.

Similarly as what Jeff did on the sus WD models (cf his alog), the trigger on DC osem values in the iop models (upper path of screenshot) should be removed to avoid this kind of situations.

This could be done during the vent period in two weeks. 

[Justin Corey Arnaud]
Even though the ISIs/HEPI were working fine, guardian has been reporting errors on ST1 and ST2 of each bsc chambers, cf screenshot. After reloading all of them, guardian is not reporting errors any more.

Authentication for ligo.org accounts in the control room started to fail at about 1:40PM (or at least that was when it was first reported).  I followed it as far as cdsldap0 logs stating slapd couldn't contact the remote server; rock.ligo-wa.caltech.edu was not pingable.  So I called Jonathan and he was able to walk me through reconfiguring slapd to use the alternate server, quartz.ligo-wa.caltech.edu which is still up and reachable.  ligo.org logins should now be functional in the control room again - Jonathan will investigate further remotely later in the day.

I've swapped out the workstations located by the test stands, they were no longer useable as configured.  The new workstations, lveaws1,2 are iMacs and connect via the wireless AP.

Reading before turning it off, 1.34X10^-04 torr.

Left the CC on for 1.5 hours.

It is off now.

(Corey, Gerardo, Patrick)

Two days ago (about 4am Thurs morning) the ISS diffracted power started to drift down from about 6.7% down to 2.0%.  Once at 2%, it started to go into oscillations (roughly around 3am this morning); see attached 2-day trend.

Without instructions on how to address this (and no recent alogs noting this behavior), we scratched our heads a bit, moved some gains and hit buttons to no effect.  We returned back to the original state.  Then Patrick suggested we try switching from PD A to PD B, and this appeared to stop the oscillations.  It took us to a value of about 5%.  Unfortunately, it looks like the power is still sloping down however.  (Curious to see if the ISS goes back into oscillations at 9pm tonight).

After checking with commissioners to verify no one was performing any measurements on h1lsc, I manually cleared the test point list to avoid overloading the awgtpman process.  Test points had apparently been orphaned at some point, corresponding to the following channels:

H1:LSC-REFLAIR_A_RF45_I_ERR_DQ
H1:LSC-REFLAIR_A_RF45_Q_ERR_DQ
H1:LSC-REFLAIR_B_RF135_I_ERR_DQ
H1:LSC-REFLAIR_B_RF135_Q_ERR_DQ
H1:LSC-PRCL_EXC

The long term storage Nitrogen purge system has started testing today. It will be venting through a regulator and hose near HAM12 over the weekend. This purging shouldn't have an impact on any activities inside the LVEA. CP2 levels may need increased attention until we can see the impact that the purge line has on the LN2 dewar.

This evening Lisa pointed out that the low carrier buildup can be explained by misalignment in the Y arm.

I spent an hour to carefully adjust the alignment. Indeed, after the alignment, I got a cavity flash of 45 (normalized for a single arm build up) which is the highest we ever obtained. Also, the funny REFL9I offset disappeared and I could see a PDH-looking signal there when CARM passed through a resonance.

What I did:

• Aligned ETMY to maximize the IR in Y. (CAREFUL: This is an opposite way of the proposed global alignment procedure)
• Then steered TMSY and added an offset in the TMSY QPDs to recover a high buildup for the green light.
  • The resultant green buildup is now 10% smaller than the usual, but optimized for the infrared. Not terrible.
  • ALS-Y_QPD_A_PIT now has an intentional offset of 0.8. This gave a high buildup for the green light.
  • I did not steer ITMY or BS at all in this process. In other words, I relied on the PRMI local alignment.
  • Then I did a mode scan of the Y arm to see how good the alignment is. The spatial HOMs are now small. Their power are roughly 10-20 times smaller than the carrier 00. Good.
• I tried the locking process again, starting from a CARM offset of 700 Hz with REFL45 for PRMI. This worked fine.
  • The funny offset in REFL9I was much smaller this time. It was about 10 times smaller than yesterday. Good.
• I reduced the offset to let CARM resonate while holding PRMI with 135I and Q.
  • I didn't have to re-adjust the demod phase at all this time. It was robust until the arm cavity started building up the carrier light.
  • Apparently PRMI was not able to survive through the arm cavity resonances.
  • However if the sweep through a resonance is fast enough, PRMI does not drop the lock since the carrier does not build up so high.
• I disconnected the REFL_DC_BIAS cable from the common mode board and connected the REFL9I signal in order to try self-lcoking.
  • It seemed that a good control sign is positive at the input2 of the common mode board because this brought CARM closer to the resonance.
• I tried self-locking a couple of times with no success.
  • I was not able to approach the resonance as close as 100 Hz because of the fragile PRMI before introducing REFL9I. So I tried to add REFL9I when CARM was as far as 150 Hz or so.
  • Self-locking tends to push CARM to the resonance as expected, but IMC unlocked every time. The arm power went up to 3 or 4 before IMC unlocked.
  • I tried different gains (almost randomly) in input2, but no luck. I guess that CARM is basically too far from the resonance and therefore self-locking can not squash such a big offset by its gain.

Daniel and I restarted green WFS effort.

WFSA and WFSB were rephased using an injection into PDH CM board. Apparently somebody tried to compensate the signal differences across the quadrants when doing a similar injection as mine, and I followed that same path such that seg1 and seg3 are matched as well as seg2 and seg4.

Then I dithered PZTs at 2, 8, 11 and 13.5Hz to measure the sensing matrix, inverted the matrix, and put them in the input matrix, such that WFS_DOF3 becomes PZT1 and DOF4 PZT2. Note that both WFSs are much more sensitive to PZT2 than PZT1.

I didn't put any filter in DOF3/4 nor IP PITOFS and IP YAWOFS, but set the gain to some negative numbers.

In the input matrix of QPD alignment servo, I added a straight-through matrix to add the WFS signal.

I had a hard time working with state definition thing and maybe the guardian, so I still don't know if it works or not, but the intent is to do a high BW feedback to the PZT.