PeterK and RickS

- FSS AOM replaced.  Heat sink, aluminum baseplate, kapton insulators, nylon screws added. (see photo below)

- Measured RF power at input to AOM: 22.5 Vp-p -> 7.96 Vrms -> 1.27 W.  About right.

- Aligned AOM.  Power just upstream of AOM: 68 mW; Power just downstream: 58 mW.  85% efficiency.  Very good.

- Second pass, measured just upstream of EOM: 47 mW; 81% efficiency.  Good.  Double-pass efficiency 69%.  Good.

- Power downstream of EOM, downstream of RC modematching lens L12: 47 mW.  Good.

- M27, first turning mirror downstream of EOM was not locked, now is.

- Aligned into reference cavity using two periscope mirrors.  Max Tx PD DC out: 2.37 V.  Locked both periscope mirror mounts.  TxPD DCout after locking mounts: 2.35 V.

- Centered beam on RFPD.  Locked all three actuators on first steering mirror upstream of RFPD.

- FSS RFPD unlocked: 360 mW; locked: 37 mV -> 90% visibility.  Not too bad.

- TTFSS gains (FAST/Common): 15/30 dB; measured UGF 340 kHz; phase margin > 50 deg.  Notch at 770 kHz.  Peaks at 1.77, 1.93, and 2.48 MHz up to within 2-3 dB of unity gain (see photo below).  Probably should be addressed by rolling the loop off more aggressively above 1 MHz, or so.

- Frontend watchdog disabled at start of work, enabled at close of work.

Overall, loop seems to be functioning well.

Relative power noise measurement looks nominal.

The frequency noise looks similar to that of previous weeks.  The low frequency (sub 100 Hz) part of the spectrum is higher than the
reference measurement.

The beam pointing measurement looks different to the previous week's.  Everything is higher by a factor of ~10.  Measurements are worse
than the reference measurement above 100 Hz.

The mode scan looks nominal.  Higher order mode count 53, higher order mode power 4.6%.

The first loop relative power noise looks where it should now.  Flat down to about 3 Hz at ~1.4E-7/Sqrt[Hz].  Average diffraction
percentage is 9%.  A little larger due to the second loop being commissioned.

I bagged & tagged items which I assume were left over from various installations over the summer.  I left bags in cleanroom for owners to put away.

There is a cleanroom between HAM4/5 which is still powered on (not sure what this is being used for nowadays...TCS?).  Of course, the big cleanrooms in the West Bay are being used for SUS 3IFO.

Top View Photos were taken for ISCT1, IOHT2L, IOHT2R, & ISCT6.

Incursions were from 9:00-10:00am.

Added water to the chiller, 210 ml.

Reset of HEPI L4C Accumulated WD Counters for HAM2 10:48 am.

Stopped the slave replication process on h1conlog3.
Ran mysqldump -u root -p h1conlog > h1conlog_dump_7oct2014.sql on h1conlog3.
Started the slave replication process on h1conlog3.
Took about 10 minutes or so.

Tarred the backup file and moved it to:
/ligo/lho/data/conlog/h1/backups/h1conlog_dump_7oct2014.sql.tgz
The size is 356M.

I also added Dave B. to be emailed the hourly list of frequently changing channels. However, he does not seem to be receiving them yet. When this gets sorted out I will close WP 4891.

Last week we were wondering about possible ITMX excess motions. I reploted the optical lever motion from last friday including the calibration correction factors that Jeff posted yesterday. The first figure is the initial plot. The second one includes the correction.

While ITMX still show a large half-hour notion, the RMS values of  the ITMs tends to be very similar dowm to 10 mHZ.  In this measurement, the RMS values were around 20 nRad rms, both for pitch and yaw.

model restarts logged for Mon 06/Oct/2014
2014_10_06 01:32 h1fw1
2014_10_06 11:44 h1fw0

unexpected fw restarts

Weekly trend figures.

PeterK RickS

We are about to go out to the Laser Area Enclosure early today to swap out the suspect AOM in the FSS optical path to the reference cavity, peak up the alignment, lock down mounts, etc. in an effort to reduce the alignment drifts we have been observing almost since the system was installed (see work permit).

I have had a difficulty transitioning the SRCL signal from the 1f to 3f signal. Not solved yet.

After playing with ALS DIFF, I went through the initial alignment process and then moved onto the DRMI. As tested before (alog 14283), the 1f locking with REFLAIR was fine with a laser power of 10 W incident on IMC. However I kept failing in the transition from the 1f to 3f signals tonight. It was due to the SRCL loop which did not like the 3f signal tonight for unknown reason. The PRCL and MICH loops could be transitioned to RF27_I and RF135_Q respectively without a problem. But SRCL seemed to saturate the M2 stage DAC every time (??) when I tried to engaged RF135_I. I tried adjusting the demod phase, but did not seem to help. Also checked the optical gain by exciting SRCL and confirmed that the input element of -2 which was taken care by the guardian is right. Also tried it with two whitening stages on in REFL135, but this did not help either.

Note that the build up of the sideband power looked high tonight:

• ASAIR_RF90 = 3700 cnts
• POPAIR_RF18 = 220 uW

Also, I had the modified L2P decoupling filter engaged on the M2 stage of SRM (see alog 14304) all the time tonight.

Alexa, Sheila, Kiwamu

we were able to lock ALS diff somewhat stably tonight, with a ugf around 5.5 Hz. 

• by comparing our settings with those in alog 11877 Alexa found that we were missing a high pass in the L3 lock filters for ETMX.  We copied this, as well as FM6 and FM 7 (part of our plant inversion) to ETMY. 
• L1 LOCK_L filters of ETMY were changed to match the ETMX filters. 
• we were then able to lock with the 2 boosts on, and a gain of 0.4 in the input matrix.  This was stable, and stayed locked, but it seems as though we must not have had much phase margin with such a low ugf (1Hz) and both boosts on.
• With the DARM offset set to 0.0195 we locked the 01 and 00 mode of the IR to the Y-arm.
• We eventually rung up the bounce and roll modes of both quad, making locking difficult for some time.
• We added an L2P filter for ETMY L1 drive align (FM 8 z0.5, p10), that has the same gain at high and low frequencies as the previous filters (FM1 + FM2) but without the high Q resonances in between. This filter seemed to help ... ??
• Kiwmau changed the coild driver state request for L1 from 2 to 1 for both ETMs, so that the low pass filters are off. This allowed us to set the input matrix gain of DARM to 1 and brought the UGF up to 5.5Hz for DARM (for this scenario the two boosts of DARM were off).

J. Kissel

Following a similar procedure as was done for the ITMs (see LHO aLOG 14265), I've refined the calibration for the H1 SUS BS optical lever. The new calibrations are
BS P 6.9522 [ct/urad]
BS Y 3.8899 [ct/urad]

They've not yet been installed; will install tomorrow during maintenance.

DETAILS
------------
Currently, the alignment slider calibration gains are 
4.714 [ct/"urad"]
4.268 [ct/"urad"]
based on dead-reckoned knowledge of the actuation chain (see LLO aLOG 5362).

Sheila and Alexa recently found the alignment values for the beam splitter which gets red light onto the ETMY baffle PDs:
            P ["urad"]    Y ["urad"]
ETMY PD1      184.0        -255.0
ETMY PD4      237.1        -287.7
or a displacement of 
BS P    53.12 * 2 = 106.2 ["urad"]
BS Y    23.70 * 2 =  65.4 ["urad"]
where the factor of two comes from the single bounce optical lever effect.

I spoke with Gerardo who informed me that the numbers Keita had posted (LHO aLOG 9087) for the locations of the baffle PDs on the Arm Cavity Baffles are slightly off from reality. He gave me links to D1200296 (ETM) and D1200313 (ITM), which indicate that the PD locations are identical between an ITM and ETM baffle, and are 11.329 [inches] = 0.288 [m] apart in vertical, and 11.313 [inches] = 0.287 [m] apart in horizontal. Again using 3994.5 [m] for the length of the arm (LHO aLOG 11611), and adding 4.847+0.100+0.020+0.200 = 5.167 [m] for the distance between the HR surface of the BS and the back of the CP, through the thin CP, through the ITM QUAD's reaction-to-main chain gap, and through to the HR surface of ITM, respectively (D0901920), that's a lever arm of 3999.7 [m]. Hence, a displacement of
BS P   0.288 [m] / 3999.7 [m] = 72.01 [urad]
BS Y   0.287 [m] / 3999.7 [m] = 71.76 [urad]

The alignment offset slider gains should therefore be corrected by 
BS P  72.01 / 106.2 = 0.67806 [urad/"urad"]
BS Y  71.76 / 65.4  = 1.0972  [urad/"urad"]
or
BS P  1.4748 ["urad"/urad]
BS Y  0.91141 ["urad"/urad]

The new slider gains should therefore be
BS P    4.714 [ct/"urad"] * 1.4748 ["urad"/urad] = 6.9522 [ct/urad]
BS Y    4.268 [ct/"urad"] * 0.9114 ["urad"/urad] = 3.8899 [ct/urad]

We're now storing 4 alignments for the BS, 
                      P ["urad"]       Y  ["urad"]
BS Aligned              210.6             -271.4
   Misaligned           236.5             -287
   To EY ACB PD1        184               -255
   To EY ACB PD4        237.1             -287.7

which should therefore become,

                         P [urad]     Y [urad]
BS Aligned                142.8        -297.3
   Misaligned             160.3        -314.9
   To EY ACB PD1          124.76        160.77
   To EY ACB PD2          160.7         315.66

To do:
- Update calibration in OPTICALIGN gain
- Update calibration in M1 LOCK bank
- Update, confirm, and save corrected alignments
- Capture new safe.snap

K. Venkateswara

This week, I will be installing and testing the "damping turn-table" to actively damp the beam-balance in the BRS whenever it gets driven to large amplitudes.

BRS had stopped working a few days back, so I took a look at the BRS-DAQ laptop today. Just as before 13817 the CCD had temporarily stopped working causing the program to freeze up. Still not clear on why this happens but it looks like the crashes are irregular.

After restarting the program on the laptop, I noticed that the main-mirror pattern had barely drifted off the CCD (it was missing one peak out of 38). To correct this I adjusted the left-right center of mass (COM) of the balance using the small flexible adjuster located in the front face of BRS. The correction was an iterative process and took about 30-45 mins. For future reference, moving the moveable rod (located on the balance) towards the right (or south) shifts the center of the pattern to the right and vice versa.

After damping the balance and turning on the program, I noticed that there was some excess noise visible in the output going to the CDS which seemed to be due to the lack of an anti-aliasing low pass filter in the code. I had bypassed the low-pass filter to save computation cost, but apparently there is more high-frequency noise in the CCD output than before. After enabling the anti-aliasing filter, the output going to CDS looked clean again.

Over the next few days Jeff and I'll also try to resume where he left off here: 14047. I've attached a pdf showing the BRS, GND_STS and ST1_T240 measurements for comparison. This data set was measured this afternoon starting at: 1096665586. ST1 motion is smaller now in 10-100 mHz band after improvements to the configurations over the last several weeks, but there is still a lot of coherence with the GND sensor.

(Keita Daniel)

We are setting up the feedback paths for the EY WFS servos. Simple 1/s filters are currently loaded into DOF_3 and DOF_4.

We noticed that the IPCs for feeding back to the test masses were set up in the ISCEY model, but that they were only connected for EX in the ASC model. The ASC model was changed on disk but no yet committed.

The cameras with the green filters blocking the 1064nm wavelength are working on the ITMs. Exposure set to 30,000. The images look rather different between X and Y, so.

Added additional offsets and normalization capabilities to the camera position code in the ISC end station models. Needs to be loaded. A new medm screen was also added.

LVEA is Laser Hazard

09:15 Ken – Finished installing power receptacles in LVEA. Going to do same at the end stations. 
09:39 Betsy & Travis – Working in LVEA west bay on 3IFO Quads
09:57 Kyle – At Ham6 to turn off rotating pumps and start Ion pumps
10:04 Krishner – Going to End-X to install BRS sensor turntable
10:10 Filiberto – Recovering electrical equipment from the Ham2 area
11:50 Karen – Cleaning at End-Y. High dust counts (+10k range) and a lot of moths
13:20 Gerardo & Peter – Working on OFI optical alignment in H2 PSL enclosure
13:20 Cris – Cleaning at End-X
14:38 Betsy – Working at SUS test stand LVEA west bay
15:28 BFI on site to pick up recycling at staging building
 

Trying a small modification to the ITMY blends tonight. Because the Z/RZ is suspected to be caused by actuator drive currents, Sheila has allowed me to switch the Z on St1 to a higher blend. If this proves unworkable for arm work tonight, the blend can be switched back easily enough to Tbetter on Z. Getting Ryan's 90mhz blend is possible, but right now would require turning off the Z isolation loop, a bunch of extra clicks( switch each of the individual current blends), then turning the loop back on.

I'm attaching some data that prompted the change. Fabrice made a script last week that plots the coherence of the ISI St1 T240's to the Oplev signals. I messed with it this morning a little to look at all degrees of freedom, shown in the attached plots. The first 2 pages show ISI to oplev pitch, the last 2 are ISI to oplev yaw, from Sunday night, with ITMY in our new <a href="https://alog.ligo-wa.caltech.edu/aLOG/index.php?callRep=14284">"standard configuration"</a>. Basically, red means high coherence, meaning the ISI is strongly coupled to the motion the oplev is seeing, or something. We think that Z isolation is not strongly coupled to optic motion, so reducing isolation there won't negatively affect the optic. But, reducing the amount of drive on Z, I hope, will reduce the amount of RZ/yaw that is induced.

Unless someone is running a configuration test, this state is not nominal and should be corrected.  Usually, we can switch this with out too much stirring up of the platform.