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.

This is really the next big watchdog issue: regular IFO commissioning activity is causing the SEI watchdogs to trip.  We need to investigate the issue further, but what we definitely know is that when we lose the ALS locks the ETM ISI watchdogs trip.  It's usually just in stage 2 actuators, but also sometimes both ISI stages and more than just the actuators.  This is reducing efficiency during commissioning, so we need to back off on the saturation count for the SEI watchdogs some more.

SR3 measurements will be running overnight on opsws1.

Guardian states "undamping/undamped" were added to sus.py. It basically set the correct switches for testing purposes (undamped tfs). This state can be called from matlab before running a TF using (e.g for SR3):

system('caput H1:GRD-SUS_SR3_REQUEST UNDAMPED')

Only SR3 guardian was restarted

Greg, Thomas, David

Corner HWS table:
- both end-X and end-Y in-air optics have been aligned (using the fibre coupled 532nm source) from the source to the periscope. Slight tweaking may be required once the SLED is connected up.
- air lens and collimator temperature sensors for both end-X and end-Y are connected up and are working
- HWS for both end-X and end-Y are yet to be assembled/installed
- image of the corner HWS table attached

TCSX:
- laser has been operating all day. Thomas working on connecting up FLIR camera computer. 
- laser will be left running again overnight to allow performance monitoring

TCSY:
- alignment confirmed through the AOM, while the picomotor mirrors were repositioned. Alignment is now through the second pick off optic, which is just before the HWP and polarisers. 
- CP power control polarisers were removed and checked for pitching using the reflection from a HeNe (set up to be at a flat 4" beam height). Initially the first polariser had pitched the beam down 0.25" at a distance of 20". This pitching was removed by loosening and retightening the bolts that secure the polariser mount to the mounting bracket. Polariser plate was also observed to move in this mount, further changing this pitch. This polariser plate is secured in the mount using a nylon screw, and when tightened improves this a bit. Second polariser appeared to be slighly better. Further investigation required. 

A representative from Electric Utilities Dispatch called the control room to report that they are having power issues, but he stressed that we should not be affected.  He did mention, though, that if we experienced and power glitches today they could have been associated with the fault that they experienced.

He signed off by saying "I hope you understand the gravity of the situation", followed by a brief pause, then harty laughter.  Thos jokers...

F. Clara, R. McCarthy and R. Weiss
We used the capacitance bridge circuit to establish the wiring of the ETMY. We found (as Keita had guessed)
that the common bias line was connected to cable 1 and not cable 3. The capacitance change between the bias trace
and the individual quadrant control traces was measured as the recoil mass and the test mass pendulated 
driven by the ground noise. The seismic system and all suspension damping was turned off during the
measurement. The accompanying figure shows the voltage spectrum at the output of the lock-in amplifier
for each quadrant. The number at the right is the amplitude of the pendulum peak for each quadrant. The smaller
value for the capacitance change between cable 1 and 5 is somewhat worrisome. If this measurement needs to be repeated
to validate a difference in the force/voltage^2 ratio for the quadrants, it would be best to deliberately apply a force
to the penultimate mass at the resonance frequency of the pendulation rather than to rely on the ground noise. The
peak measured in all the quadrants is at 0.4297 Hz

Yesterday I edited the ALS diff guardian in order to add new states which automatically find an IR resonance. The requestable state is called IR_FOUND. The concept is the same as that of ALS comm. It tries two specific DARM OFFSET places and checks the arm build up in Y arm. If it doesn't find a high buildup, it times out and falls to a failure state, called NO_IR_FOUND. At this point the user should manually find a resonance to get out of this state.

The power code for the EY laser was found to be disconnected. According to a trend, this happened at 9:20 AM this morning. Probably people working around there accidentally disconnected it.

I made a new BSC-ISI overview screen, with a related display, to support Fabrice's new Z drive to RZ T240 decoupling.

The use of the feature requires a model change which has only been installed on BSC-ITMY so far. It will be installed on the other units uppon re-compile/restart once the related ECR is filed and approved. Hence, the sitemap was modified to load the new display for ITMY only -r8044

The new BSC-ISI MEDM screens are commited in the svn:
opt/rtcs/userapps/trunk/isi/common/medm -r8045

• ISI_CUST_CHAMBER_OVERVIEW_Z_to_RZ_Decoupling.adl 
• ISI_CUST_CHAMBER_ST1_Z_TO_RZ_DECOUPLING

For some reason, the fonts look good on the editor, but not in run-mode (see attached screenshot)

8:38 am, David H. to CS VEA, Hartman table work.
8:53 am, Betsy to CS VEA, looking for parts.
9:00 am, Richard, Rai and Filiberto to Y-End VEA, ESD testing.
9:30 am, Keita and Daniel report a moth problem at X-End Station, no success on trapping the insects.
10:05 am, Cyrus and Adrian to Y-End VEA, upgrade CDS computers.
10:35 am, Bubba and crew CS VEA, remove HAM arm from HAM5 north entrance.
10:45 am, Betsy to CS VEA, West bay area looking for parts.
11:45 am, Cyrus and Adrian to Y-End VEA, install mice on CDS machines.
1:29 pm, Richard, Rai and Filiberto to Y-End VEA, ESD work.
2:47 pm, Received a call from power company, power glitch/outage on grid, reported to Richard M.
3:10 pm, Filiberto moving ESD test equipment from Y-End station to X-End station.
3:30 pm, Cyrus and Adrian to H1CER, upgrade CDS computer.
4:15 pm, Kiwamu to Y-End VEA, checking laser status, no light.

Did the same thing as X (3Hz injection to ESD each quadrant, with various offsets in DC and quadrants, measured Oplev response). And it didn't make sense (first attachment), nothing looked like a nice simple function of voltage difference.

That's until you notice that at least UL, UR and LR behave as if the bias voltage stayed the same for the entire measurement. In the second plot, I used the same data as the first one but assumed that the bias stayed at zero volt, and you see that UL, UR and LR looked quite nice. The only odd thing is LL.

So I assumed that LL was somehow cross-wired to the DC bias. I give LL -377, 0 or 377 volt, and repeated the same measurement (I used "DC" as a replacement for LL).

This time it makes much more sense (3rd plot). Comparing it with X ESD, assuming that the oplev sign convention is the same for X and Y (which should be the case), the conclusion is that:

1. LL is connected to the DC bias.
2. DC is connected to UR.
3. UL is connected to LR.
4. UR is connected to UL.
5. LR is connected to LL.

Or, if the oplev sign for P is the same but Y is the opposite of EX (which should not be the case)

1. LL is connected to the DC bias.
2. DC is UL.
3. UL is LL.
4. UR is UR.
5. LR is LR.

Anyway, the effective bias voltage etc. are:

Seems like the slopes are about the same as EX though DC is somewhat weaker.

Also, DC has a crazy offset which, if due to the charging, is equivalent of -842V (PIT) and -460V (YAW).

I manually measured the equivalent bias voltage of ESD caused by the charging for ETMX by looking at the oplev.

I changed the bias voltage (-377V, 0, 377V) and measured the transfer coefficients from the drive to the quadrant to the oplev at 3Hz.

In the case of UL and LL, I also put some offset in the quadrant output so I have a larger dc voltage difference between the bias and the quadrant.

As you can see, though it's not a perfect line as you can see in UL and LL, it looks very reasonable in that the absolute value of the slope of four quadrants are quite similar, plus PIT/YAW makes perfect sense.

The effective bias voltage obtained from PIT data and YAW data are different because it is dependent on where the charge is.

For each quadrant I fit the three data points that correspond to no offset in the quadrant itself and obtained these:

I found ETMY-ISI drive going up to huge numbers with the masterswitch off. Nothing was going out to the DAC since the masterswitch was off, but the Guardian should have turned the ISO loops off to prevent sending a big kick into the ISI when the master switch is turned back on. Jamie is going to provide a fix for this: The ISI will go into the "Offline" state, and turn back on from there, anytime its masterswitch is truned off.

As a side note, we should not turn the ISI off using the masterswitch while it is running. In this situation, the "Offline" state should have been requested from the ISI's Guardian menu.

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.

Cyrus, Adrian

We've changed the OS on the workstations at EY (eyws0, wyws1) from Mac OS to Linux, matching the current setup at EX (now that the bugs seem to be mostly worked out).

(John W., Gerardo M.)
The cold cathode was turned off in an attempt to extend its life.
Pressure before turning it off was 6.10x10^-05 torr.
The CC will be turned on and reading will be posted to keep track of the pressure.
However the CC will be off over the weekend.

Minutes taken by Corey G.

alog down
TCS:  have light on cameras, hartman work this morning & laser hazard in afternoon

HAM4
OFI:  installed & roughly located
Apollo:  request to remove HAM4 installation arm when convenient
Baffle installation remains
SEI:  balanced, may be unlocking HEPI soon

HAM5
sei awaiting final payload

HAM6
sled work in Optics Lab
will be Laser Hazard intermittently

ACB finished yesterday, will start CPB

Apollo:  HEPI plumbing

EY ESD testing (swinging etmy) this morning Rai/Richard/Filiberto

ISS PD Array cont. (Peter King)