The following electronics were installed at EY and EX. 18 Bit AI Chassis S1203483 - EX 18 Bit AI Chassis S1203519 - EY Anti-Alias Chassis S1400574 - EX Anti-Alias Chassis S1400575 - EY Still waiting on cables from vendor that still need to get pulled.
8:17 am, Peter K and Rick S working inside the H1 PSL laser enclosure.
8:20 am, Hugh to CS VEA, survey of different chambers for CPS grounds.
8:50 am, Patrick from CS CR, conlog work, see his entry for more information.
9:28 am, Hugh to visit both end stations, continue with survey for CPS grounds.
9:30 am, Dave and Jim from somewhere in the CS, work per WP#4887.
9:37 am, Filiberto to visit both end stations, work on WP#4892.
9:48 am, Cyrus to Y-End station VEA, work on HWS computer.
10:10 am, Travis and Betsy to CS VEA, West bay work.
10:52 am, Aaron to CS VEA, install camera cable for TCS-Y, close to BSC1.
12:10 pm, Hugh to CS VEA, to add/install CPS ground @ BSC1.
12:15 pm, Krishna to X-End VEA, UW-PEM work.
1:30 pm, Filiberto to visit both End Stations, new location of cables need new labels.
1:56 pm, Betsy to CS VEA, work @ West bay, drill on hand.
2:12 pm, Jason and Doug to CS VEA, retrieve equipment.<---did not retrieve it but equipment was located.
2:35 pm, Filiberto to X-End station, power cycle equipment.
3:10 pm, Dave and Jim to X-end station, bring up equipment after power cycle.
3:21 pm, Andres and Jeff to visit both end stations, retrive parts/components.
3:52 pm, Travis to CS VEA, locate and retrive missing laser power meter that someone swiped.
Reloaded the iscex/ey and asc models to enable the new camera channels.
The attached snap shows
When the Y-arm is locked on green this should now give an error signal to the green alignment system.
The script didn't work until I swapped H1:VID-CAM24_X and H1:VID-CAM24_Y:
#!/bin/bash
while [ true ]; do
ezcawrite H1:ALS-Y_CAM_ITM_PIT_POS 'ezcaread H1:VID-CAM24_Y|awk '{print $3}''
ezcawrite H1:ALS-Y_CAM_ITM_YAW_POS 'ezcaread H1:VID-CAM24_X|awk '{print $3}''
ezcawrite H1:ALS-Y_CAM_ITM_SUM 'ezcaread H1:VID-CAM24_SUM|awk '{print $3}''
done
The first figure attached shows the optical levers motion, Monday at 1 am, with Stage 1 Z under 90 mHz blend.
The second figure attached shows the optical levers motion, Tuesday at 1:15 am (there were some offsets applied around 1:00am), with Stage 1 Z under 750 mHz blend hoping to reduce the Yaw motion at the microseism.
The input motion was very similar for the two measurements.
- Results: All units except (ETMX) show more motion in the Z 750 mHz blend configuration, as summarized in the table below; I recommend to revert the Z blend back to 90 mHz configuration to see if the results are repeatable. This can be done any time as both configurations provide similar performance anyhow (-> when it is the least disruptive for IFO locking activities),
- Other comment: it would be good to find out why ITMY and ETMY rms are dominated by features below the micro-seism (poor tilt decoupling? noisy sensor?). This is true in both blend configurations shown in these plots.
RMS value of the optical levers down to 10 mHz:
Pitch (90mHz Z blend) Pitch (750mHz Z blend) Yaw (90mHz Z blend) Yaw (750mHz Z blend)
ITMX 8 nRad 16 nRad 11 nRad 20 nRad
ITMY 29 nRad 35 nRad 63 nRad 71 nRad
ETMX 15 nRad 11 nRad 16 nRad 12 nRad
ETMY 37 nRad 43 nRad 53 nRad 62 nRad
Last week, RobertS and I determined that the North and South PSL table temperature sensors are mislabeled. North is really South, and vice-versa. The South sensor (EPICS channel calls it North) was mounted close to the two major heat sources in the Laser Room that are not water cooled: the TTFSS servo electronics and the ISS AOM driver (see "before" photo below). Today, I moved it approximately 2 ft. to the West so that is not located on the South-West corner of the table, and away from the heat sources (see second photo attached below).
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.
Isomet AOM 1205C-843 S/N 120684, purchased under P/O S127984. Replaces the AOM purchased during the Initial LIGO era.
Plot of the reference cavity transmission and pre-modecleaner output after the work on the AOM. There are two discontinuities in the reference cavity transmission. The first probably coincides with the FSS oscillations noted by Kiwamu earlier today. The second change might be due to the common gain being reduced to 18.8 from 30.0.
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:
Also, I had the modified L2P decoupling filter engaged on the M2 stage of SRM (see alog 14304) all the time tonight.
Here is a lockloss science. Not clear what exactly was going on.
I looked at three different lock loss events from yesterday. All of them were associated with very large saturation in the M2 stage of SRM which seemed to trigger instability in SRCL and destroy all the LSC loops eventually within a 2 sec or so.
The attached plot is the one from Oct-07-2014 09:24:22 UTC. In this example, PRCL and MICH had been already controlled by the 3f signals (i.e. RF27_I and RF135_Q respectively). In the middle of the plot, the SRCL 3f signal was ramped up (though it actually ramps down because of the control sign. The 1f signal was ramping down at the same time which is not shown in the plot.) Apparently the SRM M2 stage saturated quite hard. Following the M2 stage, the SRM M3 stage hit the DAC range as well. The BS and PRM M2 stages did not saturate until the loops became completely broken. An oscillatory behavior was seen in all three length signals and it was roughly at 13 Hz. Hmmm...
Alexa, Sheila, Kiwamu
we were able to lock ALS diff somewhat stably tonight, with a ugf around 5.5 Hz.
(free-swinging and in-loop spectra)
After playing with some gain settings and enabling LSC filters, I became able to robustly close the loop with a UGF of 10-ish Hz. I ended up with a L3_LOCK_GAIN of 1 for both ETMX and ETMY. In order to avoid DAC saturation I intentionally decreased the input element to 0.8. This seemed to help reducing DAC saturation events. I edited ALS_DIFF guardian accordingly. The attached below is ALS DIFF spectra of tonight:
(Red): in-loop spectrum, calibrated in um. (Blue): (almost) free-swing spectrum, calibrated in um. The blue curve was measured by conrolling ALS DIFF with an extremely low UGF. The in-loop RMS was about 600 pm which is almost the same as what we had in the HIFO-XY time (see for example, alog 11878). However, we are having 0.5-ish Hz feature in the in-loop spectrum which maybe due to some kind of angular coupling. I have not investigated this yet. Anyway, we are essentially back to the HIFO-XY performance.
(Out-of-loop measurements)
I was able to let the Y arm be on top of a resonance. A DARM offset that I found good was -0.0651.
Short term stability:
Please look at the red-ish and cyan curves which are IR_TRX and TRY respectively when the arms were held by ALS comm and diff.
Long term stability:
Things drifted on a time scale of 5-10 min. Also I noticed that the IR alignment in Y arm was not optimum. It should be roughly twice higher than it have been. Also, ETMY L2P was obviously worse than ETMX. Maybe the green alignment in the Y arm was simply not good ?
This lock strech can be found between 22:50 and 23:12 in PDT.
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.
Plots from ITMY last night with high blend on Z.
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.
switched to hi gain ~0730pdt Tuesday.
