Evan, Alexa, Sheila

We went through the DRMI initial alignment today. We were able to run PRM_ALIGN fine. When we ran SRM_ALIGN we noticed that we were not feeding back to SR2 eventhough the asc wfs were designed to do so. This was something in guardian that was not properly updated. We fixed this problem, and also adjusted the guardian offloading script to clear history of the M1 locking filters since some of these now have integrators.

DRMI locked on 3f @ 12/06/2015 16:09:55 PST. We were able to engage all the ASC wfs loops except INP1, PRC1 which feedback to PRM. At this point we took transfer functions of each loop. We found that the PRCL UGF was low, and we had to increase the PRCL gain from 11 to 22. The MICH loop was comparable to previous measurement. Meanwhile the SRCL loop seemed to lose phase on the low frequency side of the phase bubble and be a bit flatter near the UGF. Comparing the times of the two SRCL transfer functions on conlog, it appears that the switch status for the SRCL filters has been changed. More invesitgation is required. We also noticed that the BS roll mode at 25 Hz had been rung up based on the DRMI spectrum, but not enough to disturb our lock.

After about 15 min we lost lock (most likely from an excitation). We could recover the lock; however, it only stayed locked when engaging the PR3 ASC wfs feedback this time; all other loops had to be turned off. DRMI was not staying locked for long periods of time, making it hard to take measurements. We took a BS oplev spectra and saw a peak at 19.6 Hz. The oplev damping has a large notch at 19.48 Hz. According to the SUS model awiki page it doesn't seem to correspond to a particular mode ... We are not totally sure if this is what is keeping us from locking.

Jim, Sebastien

We've been investigating a little more on the HAM3-ISI issue. Quick sum up: we see a 0.6Hz sharp peak on all DOFs when the Z sensor correction is on (see logs here and here).

First we checked the electronics. We swapped the STS input cables of the AA chassis between HAM2 and HAM3. This didn't do it, and the issue stayed on HAM3. This exclude the whole STS electronics chain except the AA chassis and ADC.

But, back in the December, the sensor correction was implement with a different seismometer (which means different AA chassis and different ADC), and the peak was already here. Thus we can say with confidence that it's not an electronics issue.

From there, couple of observations:

- The unity gain frequency of the nominal blend filter is 0.6Hz.

- When we switch from the nominal blend filter to a 750mHz blend, we don't see the peak anymore.

Given that, the nominal configuration of HAM3 is the same that the other ISIs, and the problem appears only on HAM3...

Also, by looking at the local transfer functions of HAM3, we see a lost of coherence around 0.6Hz (see files attached). Rubbing might explain the whole story... A soon as we have access to the platform, we'll do a driven transfer function in this bandwitdh and double check that hypothesis. In the meantime, we keep investigating on the blend configuration.

Expect to remove BSC9 West door in the morning for a brief incursion by others followed by door install and pump down.

WIth Rick's help, we have created a composite image of ETMy before, after, and before-minus-after using Matlab.  Due to saturation of the camera's photodetector in the 'after' photo (we believe due to higher power in the arm), the particles we removed during cleaning appear magenta.  Tomorrow, I hope to do the same with the IR photos. 

I repeated the measurement from alog 15783, just checking coherence between HAMs 2&3 after we changed HAM3 to look at the right seismometer. Nothing obvious, but I found something interesting. The FIR_IN signals should all be the exactly same at this point, and so should be 100% coherent, between the chambers. The Z signal is not, but the difference is only below 50 mhz, at around .6hz the coherence is almost 100% again. Attached plot shows measurement from the middle of last ni.

LVEA: Laser Hazard
Observation Bit: Commissioning  

07:30 Karen & Cris – Cleaning in the LVEA
09:05 Aaron & Filiberto – In LVEA cabling work at HAM3 & BS
09:25 Mitch – Working in LVEA West Bay cleanroom
09:43 Hugh – Working in LVEA West Bay area
09:44 Jim & Sebastien – In CER working on HAM2 Electronics
09:53 Andres & TJ – Working on 3IFO Quad storage modifications
10:25 Manny – Cable work around H2 electronics test stand
10:37 Filiberto & Aaron – Finished pulling cables at HAM3/BS. Started terminating these cables
10:50 Sheila – Transition End-X to laser safe  
11:36 Jim & Sebastien – Back in CER working on HAM2 Electronics
11:45 Mitch & Hugh – Out of the LVEA
12:48 Manny – Pulling cables around H2 electronics test stand
14:35 Kyle – End-X to prep for vent
15:16 Kyle – Going to End-Y 
15:28 Kyle – Going back to End-X

The attached plots are from the period when there were 4 people working in the PSL enclosure on Monday (01/05/15) between 09:00 and 13:00.    

Took DBB scans of the PSL this afternoon. Plots are posted below

I had to restart the replication of the h1conlog database on h1conlog3. The replication thread timed out waiting to acquire a lock. The reported errors are attached. I am investigating.

We communicated the major crane movements with the control room commissioners.  No unusual problems.  Two BSCs and five HAMs to go.

Alexa, Thomas, Evan

Conclusion: it appears that we are at a good low loss point for the IR without having to adjust the green QPD offsets.

I locked both the IR and green to the Yarm. The alignment steps I took were the following:

1. I ran the ditherAlign.py script to center the TMSY pointing using the ITM baffle PDs.

2. I had to walk ITMY, ETMY to get high enough flashes in the arm cavity, and then was able to lock the arm on green and engage the green wfs (all 6 DOFs). This brought the green TR buildup to 1.024 cnts.

3. I then locked the IR to the Y arm and engaged the input pointing wfs to PR2, and IM4. This brought the IR TR buildup to 11 cnts.

At this spot, I measured the LSC-ASAIR_A_LF _OUT counts and found Poff = 1304(5) and Pon = 1262(4), this gives an equivalent ETM loss of L = 125(19) ppm. This was calculated following the equations in alog 15874 and 15470. This is a low enough loss spot, and both the IR and green TR buildups are high. I did not have to adjust the QPD offsets (i.e. adjust the green input pointing).

Evan and I were trying to figure out why these results are better than the previous ones in alog 15874. For one the green wfs were not enabled, although the green TR buildup was similar.  We are going to repeat this measurement over a few mornings and see how consistent of a loss we get with this alignment procedure.

Attached is a plot of EX over the past 30 hours.

Most of the meeting focused on discussion for a possible EX vent.

• SEI:  nothing to report
• 3IFO:  BSC4 moved to LVEA yesterday, Rodica here for IO eIFO, grounding plugs for SEI "cans" in LVEA (Mitch)
• CDS:  Taking down y-beam manifold electronics test stand (Richard & crew), cabling in beer garden/HAM6
• Briefly talked about PSL maintenance & some drift mysteries

Majority of meeting spent on discussion about OSEM issue at EX, gaps for EQ stops, will decide about EX incursion after SUS meeting.

No Such thing as a "Quick Vent":  Even for a QUICK task in-chamber, EVERY vent has BIG effects (time, contamination, making things worse, etc.)

Will go over Work Permits on Fri

Jim and Dave.

The SUS team brought a DAQ problem to our attention. When viewing minute trends vs second trends for a time period covering yesterday morning/afternoon the two plots did not have the same data. The minute trends are complete, the second trends have data loss. We determined the second trends showed data up to the DAQ restart at 12:36PST and then for part of the last hour. Strangely, only channels from the FE computers showed this data loss, channels from the EDCU showed second trend data over the entire time period. If the second trend time period does not include the DAQ restart, data is shown (i.e. no data is actually lost). Jim determined that this appears to be an NDS and not a dataviewer problem, we are investigating. The work around is to get the second trends in two requests, up to the DAQ shutdown (12:30 PST) and from the DAQ restart (12:40PST).

Kiwamu, Alexa, Koji, Evan

MICH dark locking adjustments

For the past few days, it has been difficult to lock MICH on a dark fringe; the velocity of the BS quickly becomes too high. Kiwamu found that turning down the gain from −500 ct/ct to −200 ct/ct during lock acquisition helps this situation; also, once locked, engaging FM2 and FM3 (rather than FM3 and FM6) seems to have a higher probability of success for keeping the Michelson locked.

DRMI ASC degredation

Trying to transition to DRMI_1F_LOCKED_ASC in the ISC_DRMI guardian will blow the lock. This appears to come down to the INP1 and PRC1 loops; the others (PRC2, MICH, SRC1, SRC2) can be engaged by hand just fine. INP1 controls PRM and IM4, and PRC1 controls just PRM. I tried locking with lower gain, with opposite sign, with the PRM M1 bleed-off disengaged, etc., but could not close either loop stably. We'll need to take a deeper look at why these loops no longer work.

BBPD spectrum

With DRMI locked on 1f, Koji and I took an RF spectrum of REFLAIR_B, using the −12 dB coupler on the diplexer (as in LHO#14796). This is the first measurement of the RF spectrum of REFLAIR_B after its modification (LHO#14925).

Using the newly setup PCal capabilites from the Control Room (thanks Dave!), I took some new photos of the ETMy optic post FC cleaning.  Although the IR only image is out of focus (I will take a new one tomorrow after refocusing the camera), the improvement if fairly evident.  The first photo is with green only locked, second photo is with IR only locked.  I used the same camera settings as were used pre-cleaning (F8, ISO 200, 30 sec. exposure, WB-cloudy).

Sheila, Thomas, Elli, Evan

We locked the Y arm in IR, and then turned on WFS loops which feed back to IM4 and PR2 in order to keep the buildup in the arm maximized. We measured the dc counts on ASAIR_A_LF. Then we unlocked the arm and measured ASAIR_A_LF again. The results are as follows:

• ASAIR_A_LF_OUT, locked: P_on = 1205(5) ct
• ASAIR_A_LF_OUT, unlocked: P_off = 1300(10) ct
• LSC-Y_TR_A_LF_OUT, locked: 11.4(1) ct

Using the formula in LHO#15470, the locked and unlocked values of ASAIR give an equivalent loss of 267(31) ppm on ETMY.

To account for the power in the sidebands, we use the modulation depths given in LHO#15674: Γ₉ = 0.219(12) and Γ₄₅ = 0.277(16). Then the power in the sidebands is P_SB = P_off × (Γ₉²+Γ₄₅²)/2 = 81(7) ct. Then using our new value for the power fraction, A² = (P_on − P_SB)/(P_off − P_SB), we get an equivalent loss of 286(33) ppm on ETMY, not accounting for mode mismatch.