Log:

• 1500 (800 PST) - IFO --> DOWN
• 1503 - Bubba starting Grouting, he will be going in and out of the southwest door of the South Bay.
• 1504 - Karen rolling up receving bay door
• 1515 - Karen/Christina heading to ends to clean
• 1519 - Peter to Diode room to turn on laser WD on the PSL Beckhoff computer
• 1520 - Patrick restarting Conlog
• 1520 - Peter back
• 1526 - Ken in the MSR to repair UPS
• 1531 - Jim B starting Frame writer work (fw0 & fw3)
• 1534 - Elli taking the IFO to measure SRC Gouy phase
• 1541 - UPS back up and running
• 1616 - Karen/Christina going from EX to EY
• 1616 - Dick G to Optics Lab
• 1626 - Kiwamu transitioning LVEA to laser SAFE
• 1626 - Jeff K to LVEA to pick up some electronics
• 1630 - Jordan/Vinny to EY switching magnetometer filter box
• 1633 - Jim B starting fw1
• 1636 - Ken to LVEA to talk to Bubba
• 1637 - Jeff K out of LVAE
• 1640 - Elli done (because we switched to laser SAFE)
• 1645 - Betsy starting EX charge measurements
• 1650 - Jeff K to EY for UIM measurement
• 1708 - Karen/Christina done with ends
• 1712 - Ken to Y28
• 1712 - Kyle to EX to replace annulus ion pump
• 1716 - Fil/Andres to X vault to look at PEM channels
• 1724 - Jim W BS exc
• 1730 - Jodi to LVEA for 3IFO whatnots
• 1745 - Jim W done
• 1748 - Jordan/Vinny to EX to swap magnetometer filter box
• 1803 - Jodi out
• 1825 - Jordan/Vinny back
• 1832 - Jodi to LVEA to look for function generator
• 1835 - Ken back
• 1850 - Jeff K done at EY
• 1853 - Jodi out
• 1900 - Betsy starting EY charge measurements
• 1911 - Dave restarting Cal/OMC models (the Duotone work)
• 1920 - Bubba/Chris out
• 1931 - Keita/Sheila into PSL to swap PZT LPF
• 2021 - Keita/Sheila out of PSL and done with PZT peri LPF
• 2021 - Nutsinee starting HWS realignment
• 2109 - Nutsinee done
• 2123 - Sheila into the CER
• 2142 - Sheila out of the CER
• 2151 - Kyle done at EX
• 2152 - Start of Locking
• 2208 - Initial alignment

Handing off to Jeff B trying to lock DRMI_1F.

Longer maintenance Day, but no huge surprises.

Pump cart running next to BSC9 until further notice

Note, when the EXC bit in the CALCS CDS overview is in alarm, we tend to open the screen CAL_INJ_CONTROL to attempt to diagnose - This shows a big red light for some ODC Channel OK Latch, leading us to misdiagnose what is actually in alarm.  We have 2 operational problems:

1) If generically, there is a red light on the CDS screen - where do you go?  Normally, we follow the logical medm and are able to get to the bottom of the red status via logical nested reds.  This is not the case for the CALCS screen - the CDS H1:FEC-117_STATE_WORD bit is RED on the H1CALCS line of the overview screen, yet this bit is nowhere on the CALCS screen.

So, where does the info come from for specifically the EXC bit of the H1CALCS state word, such that we can do something about it?

2) Someone should rework the CAL_INJ_CONTROL.adl so that it doesn't cause us to misdiagnose actual reds.  Currently, the HARDWARE INJECTIONS are out of configuration (outstanding issue to still be sorted) and yet, there is NO INDICATION of that on the CAL_INJ_CONTROL screen...  Also, the CW injection appears to be off, but there is no "red alarm" on the screen.

BTW, the HARDWARE INJ appear to be off.  They dropped around 7pm local time last night (20 hours ago).

I went in to have a quick look at the HWSX table and hoping it would be a quick fix to get the SLED beam centered without taking the Hartmann plate off. However, I couldn't get the streamed images to look any better as I move the periscope mirrors so I took the Hartmann plate off to see what the beam looks like. I've attached a picture. The earthquake stops are there so the beam *should* be  roughly centered. Is this a scaling problem? Or do we have dead pixels somewhere?

I put the Hartmann plate back on although the streamed image seems useless...

Taking over from where Leaonid left off, between last Tuesday and today I took the weekly sets of charge measurements during the Tuesday maintenance down time.  Attached are the long trend swhich now include the last 2 weeks of data.

I found that the PSL PZT peri mirror LPF (D1500001) uses 220 Ohm resistors in line with PZTs, each axis having 6uF capacitance. That gives the pole of 120 Hz, which is too high.

It turns out that LLO uses 220 kOhm, which is a bit too big.

After consulting with Peter Fritschel I decided to use 22kOhm, which gives us 1.2Hz pole.

Filiberto fitted the spare (S1500002) with 22kOhm resistors. I and Sheila went in the PSL room and swapped the old one (S1500001) with the spare.

Before the swap we checked the beam position outside of the PSL room, which was maybe 1mm lower than the marks.

After the swap the beam position didn't change and MC locked without problem.

Since IMC WFS DOF5Y loop was NOT doing anything useful these days (as the noise spectrum shape changed), and since I need to measure the TF again if we want to enable this loop, I turned off the output of the loop.

This is the new configuration for now.

Summary: We completed all of the most important PEM injections and I think we are good to go. Ambient magnetic fields are unlikely to produce DARM noise at more than 1/10 of the DARM floor. There is high magnetic coupling at the EY satellite box rack. Coupling of self-inflicted magnetic fields in the CS ebay may keep us from reaching design sensitivity unless corrected. Most site activities will not show up in DARM, but moderate impacts in the control room/EE shop/Vacuum shop etc. can produce DARM signals. Any such events can, like signals from off-site, be vetoed by redundant vibration sensors. Although vibration coupling analysis is ongoing and not presented here, ambient vibrations produce noise at near DARM floor levels at HAM2, 6 and the PSL table and dominate DARM around 300 Hz. Radio signals at 9 and 45 MHz would have to be at least 100 times background on the radio channels before they start to show in DARM. Some sensor issues are also discussed.

Introduction

Between Tuesday and Saturday, we made roughly 100 injections to measure the environmental coupling levels to the LHO interferometer. The table shows the number of locations in each building.

In most cases we attempted to inject from a great enough distance that the field levels at coupling sites would be about the same as they were at the sensors nearest to the coupling sites.  For magnetic and acoustic injections we split the potential coupling sites into regions. In the LVEA, these regions were usually the vertex, the ITM optical lever regions, the PSL, the input arm, the output arm and the electronics bay. At the end stations the regions were the VEAs and the electronics bays. For shaking, we selected particular chambers or sites that had been identified previously as coupling sites or potential coupling sites.

We started with analysis of magnetic coupling because of its importance to the stochastic GW search, and results are presented below. In addition, it is important to set up site rules for the run so analysis of site activity injections is also included here. Other coupling analyses are not yet ready, but preliminary observations are discussed below. 

Magnetic field coupling

Figure 1 summarizes results with single magnetic coupling functions for each station in meters of differential test mass motion per Tesla of magnetic field. In general, our coupling functions are applicable to signals originating at a distance from the coupling site that is large compared to the distance between the sensor and the coupling site. If the signal originates much closer to the coupling site than the sensor is, these coupling functions are likely to underestimate the resulting test mass motion. The magnetic coupling functions of Figure 1 are based on the maximum regional coupling observed at each station.  The highest of the 3 stations should be used for estimating Schumann resonance inter-site correlation.

The lower panel in Figure 1 shows S6 (iLIGO) magnetic coupling functions. At 20 Hz the highest coupling is about an order of magnitude lower than it was in iLIGO. At 100 Hz aLIGO is about 2 orders of magnitude better. This is mainly due to the lack of magnets on the test mass. The coupling functuions are not as linear in a log-log plot as they were for initial LIGO, most likely because test mass magnet coupling is no longer dominant and coupling to electronics and cables are significant contributions.

The much higher coupling at EY than at EX is likely due to coupling to cables and connectors in the satellite amp rack. We used a small coil to track the coupling to the satellite amp rack in the VEA. It was clear that the excess coupling was at this rack, and not, for example, at the rack next to it, but we could not find a specific coupling site within this rack. This is what would be expected for cable coupling and so we should probably check the cable shield grounding for the coil drive signals in this rack. However, even at this elevated coupling level, the estimated DARM noise for ambient field levels is more than 10 times lower than the O1 DARM floor.

Figure 2 shows an example of spectra from an injection. This injection focuses on the vertex, and uses a coil set up about 20m down the Y-manifold. The top plot shows magnetometer spectra and the bottom plot DARM spectra. The injection is a 6Hz ramp, producing a 6Hz comb in the red injection spectra (blue are no-injection). The amplitudes of the peaks produced in DARM are divided by the amplitudes of the peaks in the magnetometer signal to give coupling functions in m/T. Estimates of the noise contribution to DARM are made by multiplying the coupling functions by the local ambient background from the injection-free spectrum. These estimates thus assume linearity. While vibration coupling has usually been found to be linear, we have found that, in certain bands, acoustic coupling can be non-linear, in which case the estimates are upper limits. To minimize the overestimate, we try to inject with as little amplitude over ambient as possible. We have not observed non-linear magnetic coupling.

The estimate of the ambient magnetic contribution to DARM for the injection of Figure 2 is shown as black squares.  Also included in the figure are estimates for the other corner station injection zones. The closest that the estimates come to the O1 DARM noise floor is about a factor of ten below for coupling in the ebay at 12 Hz. The ebay does not have the highest coupling function, but it does have the highest ambient fields. Thus the ebay would not be the most sensitive place for Schumann resonance coupling, but, according to this estimate, coupling of self-inflicted fields in the ebay will keep us from reaching design sensitivity unless we make improvements.

Other environmental coupling

As with magnetic coupling, coupling of ambient RF (including self-inflicted) does not seem to be a problem. However, vibrational coupling noise reaches within a factor of a few of the DARM noise floor at a couple of locations, and in bands around 300 Hz dominates DARM. It is likely that our sensitivity to site activities is due to coupling through the HAM2 and 6 ISIs. We should be able to test this possibility with the coupling functions we measured for GS13s in the HAMs. In addition to HAMs, PSL table/periscope vibrations produce the peaks near 300 Hz via beam jitter, and perhaps contribute more broadly to the DARM floor.

No noise from pre-identified scattering sites

Scattering does not seem to be a problem at current sensitivities. We installed shakers at sites that had been identified through photographs taken from the points of view of the test masses and other optics in order to identify potential scattering coupling sites (here).  We mounted shakers at the GV8 valve seat, the input mode cleaner beam tube, the signal recycling cavity beam tube and the BSC2 chamber walls (connected to the TCS mirror holders), all of which had been identified in photos as potential sites (here). Increasing motion at these sites by 2 orders of magnitude did not produce features that we saw in DARM.

Sensor problems

All identified coupling sites were well covered with sensors, but we found a few sensor problems. The most important of these are problems with the VEA magnetometers at the end stations. These are essential PEM sensors since there is no redundancy. These magnetometers did detect our injected magnetic fields, but the signal conditioning boxes appear to be producing approximately 1Hz glitches that effectively raise the sensor noise floor by an order or two of magnitude. We think that it is the conditioning boxes because we swapped out the filter boxes and set up a separate magnetometer nearby that did not see these glitches. We were unable to replace the boxes because we found no working spares. If we cannot replace these by the run, I suggest swapping them with the e-bay magnetometer setups in the end stations, where there is redundancy.

A more minor problem is that the axes of the input arm magnetometer and the two VEA magnetometers appear to be incorrect. I swapped the axes on the input magnetometer, but did not get to the VEA magnetometers. These should be checked.

Incomplete injections

We ran out of time and were not able to make shaker injections at the end and mid-stations. Perhaps we can do these during the run using the commissioning budget.

Site activities

We should expect coupling of site activites since vibration coupling levels for ambient, non-transient vibration levels are near or at the DARM noise floor. Figure 3 has tables showing all of the site activity injections, with the ones that showed up in DARM marked in red, and a link to Nutsinee’s spectrogram analyses.

The things that showed up in DARM:

·       large super ball dropped in control room from about 5 feet

·       hammer dropped from 4 feet in vacuum lab next to EE shop

·       jumping in LVEA changing area

·       jumping in control room

·       setting car battery down in OSB shipping area

·       sudden braking of silver van (things fly off seat) in high bay area

Some of the things that didn’t show up in DARM

·       sudden braking (things fly off seat) in most other areas,  including just outside of EY

·       car horns

·       crowds walking in control room or halls (no jumping)

·       loud music in control room

·       rolling in chair across control room

·       bouncing on seating/exercise ball in control room

·       airlock and external door actuation

·       slamming doors in office area

·       outer roll up door actuation, OSB shipping

·       quick human movements in the OSB optics lab

In summary, sudden impacts in the control room, EE shop, vacuum lab and all other areas on the lab side of the air lock may cause events in DARM. This includes jumping, dropping heavy (>1lbs) things and quickly setting down heavy packages. I don’t think that we need to dramatically alter our usual activities because of this observation; we just need to be careful. I say this because we can veto all of these events with the highly redundant PEM and SEI vibration monitoring systems, just as we can veto signals from off-site. But impacts in the control room/lab/shop area can produce DARM events, so we should be mindful of minimizing these impacts.

We see no evidence that a drive down the arms and a trip into the mid/end stations will be more likely to produce events in DARM than control room activities. Tour crowds in the control room are also unlikely to produce DARM events, unless they jump around or knock chairs over. Just as for our own activities, we would rely on the sensor systems to veto any events that these tours produced.

We should be able to identify the coupling sites for these site activities once we have coupling functions for vibrational signals (stay tuned). In the mean time, I would speculate that the coupling sites are mainly HAM2 and 6, up through the ISI suspension, and, possibly, increased vibration of the PSL table.

Robert Schofield, Anamaria Effler, Jordan Palamos, Nutsinee Kijbunchoo, Katie Banowetz with help from crowds of others.

Updated the following ODC settings:
ASC: DHARD input range check limit from 1500cts to 2500 to avoid occasional crossing.
ASC: INP1  input range check limit from 1.5cts to 5 to avoid occasional crossing.
OMC: include bit 17 & 18 in subsystem mask (this is effectively an OMC DCPD saturation monitor).
OMC: DARM CTRL input range check limit from 120000cts to 150000 to avoid occasional crossing.
LSC, OMC, ASC: exclude ADC saturation bit from ODCmaster ADC saturation monitor:
     for ASC the CDS saturation monitor is stuck on for unknown reasons
     for LSC and OMC, the parked ALS inputs saturate the ADC constantly. 
TCS: exclude DAC saturation bit from ODCmaster DAC saturation monitor
     for TCS, the DAC saturation monitor is reporting on constantly for two channels - not sure why.

All setting changes have been accepted in SDF.

Left to do: there are some SUS filter status checks that changed their nominal state since I last updated them in August. I can only update them once the IFO is locked.

We have large glitches when we switch the coil driver state for PRM in every example that I've looked at.  This causes locklosses, about 5 over the weekend.  

One thing that we can do to make this less painfull is to move the switch earlier in the locking process (for example, we can try doing this right after DRMI locks rather than waiting until DRMI on POP).  

A real solution might be to change the front end model so that we can switch each coil separately.   

We could try tuning the delay, as described for the LLO BS 16295

Jordan Palamos, Vinny Roma

We swapped some pem magnetometer power supplies at both end stations to fix the 1Hz glitches mentioned by Robert in his alog 21272.  Since we don't have enough working boxes at the moment, both EY and EX have one of their electronics bay magnetometers disconnected. Specifically EX_MAG_SUSRACK and EY_MAG_SEIRACK (all axes) are disconnected.

Each VEA magnetometer was using a 'new style' power supply / signal conditioning box that was causing the big glitches (these glitches seemed go away when the box unplugged and running on batteries, not sure what the battery life is but I think it would be unfeasable to run as such). At both end stations we replaced these boxes with ones taken from the electronics bay (old style). After swapping, the bad glitches disappeared and the noise floors look much better. The glitchy boxes are now in the EE room.

ECR 1500312, WP 5455

The h1fw0 and h1fw1 computers have been replaced with new computers, which were formerly tested as h1fw3 and h1fw2.  The old h1fw0 and h1fw1 computers have been renamed h1tw0 and h1tw1, and have been reconfigured to write raw minute files to the locally attached SSD RAID.

Both h1fw0 and h1fw1 are now writing science, commissioning, minute trend, and second trend files to SATABoy disk arrays through the ldas gateway computers.

The myricom drivers still need to be updated and configured on h1tw0, h1tw1, h1nds0, h1nds1, and h1broadcast0.

The UPS in the MSR is back in service.  The bypass switch which failed a couple of weeks ago has been replaced.  No power glitches occurred, systems are running normally.

Sep  8 03:23:35 h1conlog1-master conlog: ../conlog.cpp: 301: process_cac_messages: MySQL Exception: Error: Out of range value for column 'value' at row 1: Error code: 1264: SQLState: 22003: Exiting.

Also took the opportunity to reconfigure the replica to allow connections from other hosts. (WP 5481)

Dan, Evan

This evening we made a qualitative study of the coupling of beam jitter before the IMC into DARM.  This is going to need more attention, but it looks like the quiescent noise level may be as high as 10% of the DARM noise floor around 200Hz.  While we don't yet understand the coupling mechanism, this might explain some of the excess noise between 100-200Hz in the latest noise budget.

We drove IMC-PZT with white noise in pitch, and then yaw.  The amplitude was chosen to raise the broadband noise measured by IMC-WFS_A_I_{PIT,YAW} to approximately 10x the quiescent noise floor.  This isn't a pure out-of-loop sensor, and since we were driving the control point of the DOF3 and DOF5 loops of the IMC alignment channels we will need to work out the loop suppression to get an idea of how much input beam motion was being generated.  Unfortunately we don't have a true out-of-loop sensor of alignment before the IMC.  We may try this test again with the loops off, or the gain reduced, or calibrate the motion using the IMC WFS dc channels with the IMC unlocked.  Recall that Keita has commissioned the DOF5 YAW loop to suppress the intensity noise around 300Hz.

The two attached plots show the coherence between the excitation channel (PIT or YAW) and various interferometer channels.  The coupling from YAW is much worse: at 200Hz, an excitation 10x larger than normal noise (we think) generates coherence around 0.6, so the quiescent level could generate a few percent of the DARM noise.  Looking at these plots has us pretty stumped.  How does input beam jitter couple into DARM?  If it's jitter --> intensity noise, why isn't it coherent with something like REFL_A_LF or POP_A_LF (not shown, but zero)? 

The third plot is a comparison of various channels with the excitation on (red) and off (blue).  Note the DCPD sum in the upper right corner.  Will have to think more about this after getting some slpee.

Eric, Cheryl

Following advice from D Shoemaker et al., we have disabled the LIMIT on the HWINJ filter bank. The change was made at approximately GPS = 1125361473. The LLO LIMIT was turned off earlier today:

https://alog.ligo-la.caltech.edu/aLOG/index.php?callRep=20249