Alexa, Keita, Evan

Alexa and I performed our usual loss measurement: P_on = 1257(5) ct, P_off = 1304(2) ct, giving a loss of 140(16) ppm in the Y arm.

Next, we wanted to assess the amount of scatter in the arms by looking at the amount of IR light on the baffle PDs. With the arm locked to IR and the IR WFS running, we misaligned the green light and looked at the ITM/ETM baffle PDs, both with their 40 dB and 60 dB gain settings. Then we removed the IR from the arm by unlocking the modecleaner and misaligning PR2. This allows us to get the dark counts on the baffle PDs.

Relevant times are as follows, all on 2015-01-09 UTC:

• 18:25:15 to 18:26:15 – Y arm locked on IR, PD gains are 40 dB
• 18:27:35 to 18:28:35 – Y arm locked on IR, PD gains are 60 dB
• 18:31:10 to 18:32:10 – no IR, PD gains are 60 dB
• 18:33:00 to 18:34:00 – no IR, PD gains are 40 dB

We're still working on analyzing the data.

Alexa, Kiwamu, Sheila, Koji, Evan

DRMI ASC

Finally we were able to lock DRMI with the high-bandwidth ASC loops.

The key here was to move IM4 so as to center the forward-transmitted beam on POP B. In addition to reducing the amount of offset for the INP error signals, we believe (based on camera images) that this reduced the amount of light scattered on the PR2 baffle.

After moving IM4, we then adjusted PRM and PR2 so that PRX would lock again. We then proceeded with the usual initial alignment of the corner optics.

Once DRMI had locked, we engaged the MICH, SRC1, and SRC2 loops without issue, and then transitioned them to high bandwidth (by turning off the -20 dB filters and ramping down the BS oplev damping).

Then we were able to engage the PRC1_P and PRC2_P loops without issue, and transition them to high bandwidth (by turning off the -20 dB filters, and turning on the PRM M1 and PR3 M1 locking filters).

Initially we had difficulty turning on PRC1_Y and PRC2_Y. However, we found that we could get them to work by engaging them in close succession. Kiwamu conjectures that there may be some gain heirarchy at work here.

Then we were able to engage INP1_P. Initially we put in an offset at the error point so that the loop would not immediately try to integrate away the error signal dc value. However, we were able to turn the offset off without issue.

The only tricky business here was INP1_Y. At one point (before working on the PRC loops), we turned it on (with an offset) and found that we had to flip the sign of the gain (from 300 ct/ct to -300 ct/ct) to keep the POP buildup stable. However, once we engaged it last (after all the other loops), we found that the original gain works fine. It's still unclear what's going on here.

The new slider values for IM4 are outside the "safe" range found by Keita and Alexa (LHO#). But since the IMC pointing has been changed since then, it's not clear that these safe values are still valid.

We started a (hopefully) long DRMI1f+ASC lock at 2015-01-10 05:21:00 UTC.

DRMI lock acquisition

When DRMI locking becomes sluggish, we found it is helpful to misalign the SRM, then wait for PRMI to lock, then adjust PRM and BS to maximize POPAIR_B_RF18. Then upon breaking the lock an realigning SRM, DRMI appears to lock more quickly.

Suspension clearance issues require BSC9 incursion to correct -> Aborted pump down 

Kyle, Gerardo -> 

4 hr. vent of X-end  

Kyle, Gerardo, Bubba -> 

Removed BSC9 West door -> Installed BSC9 West door 

Kyle -> 

Decoupled purge/vent line -> X-end "Blow down" air dew point measured -11C -> Began pumping BSC9 annulus -> Expect to begin "attended" rough pumping of X-end late Saturday morning for ??? duration and finish on Sunday 

With a fresh set of expert eyes on site in the form of Brett Shapiro, we embarked on evaluating ETMx in search of the pesky rubbing EQ stop.  Having theoretically narrowed the possibilites down to the PUM stage of the main chain, I started by evaluating the bottom barrel stops of the PUM on the right side (SUS convention, looking from reaction chain down the arm).  While the stops looked closer than the recently adjusted test mass stops (as was expected), I did not see anything glaring.  I then moved to the left side of the suspension and very quickly identified the possible culprit.  The bottom barrel stop on the left side nearest the reaction chain was very close to the mass, although not touching in the in-air state (as has been verified multiple times via in-air TFs), it was ~0.1-0.2mm from the mass.  I also noted that the lock nuts on neither of the left side lower barrel stops were tight, in fact they were several millimeters from the EQ stop mount bar.  We continued to evaluate the remaining bottom-side stops at all stages looking for other possible sources of rubbing but did not find any.  As per guidance from SYS/SUS representatives, we readjusted ALL bottom-side EQ stops at the PUM, UIM, and Top Mass stages to the erring-on-the-larger-side of the 1mm spec.  We also re-verified that the Test Mass and ERM stops were set to the 1.5mm spec set by Betsy earlier this week.  Fingers crossed!

The above narrative focuses on the main goal of the incursion, finding the rubbing source.  The step by step checklist summary is as follows:

• Particle counts prior to door removal: 60@0.3um, 20@0.5um.
• Evalutate HR surface of TM pre-work.  Nothing egregious.
• Adjusted EQ stops as described above.
• Evaluated HR surface of TM post-work.  No noticeable change vs. pre-work.  Cursory N2 blow.
• Particle counts in-chamber post-work: 750@0.3um, 410@0.5um.
• Removed tools and stool.
• Particle counts in-chamber post-exit: 140@0.3um, 70@0.5um.
• Took quick TFs of V and P for both M0 and R0 (since both had been touched).  TFs look good.
• Handover to door crew.

Betsy plans to run remote TFs on this SUS over the weekend to evaluate it's health on an ongoing basis.  Hopefully she will NOT call Kyle's cell!

Linking some BSC-ISI modeling notes from SEI log 672.

I got the LLO test mass charge measuring script running here at LHO. There was an NDS error initially that Dave Barker magically made go away. Otherwise, the script required no modification other than some missing commas in the bias voltage definition. There is a timing error that seems to pop up at pseudo random times. In these cases, the excitation appears shifted from the oplev response by 9 sec. See UR_timing_err.pdf.  Of all the ESD quadrants it most often occurs on the UR, though I saw it once on upper left. Not sure if it has something to do with the settings of the script. The way it is now, the timing error has appeared in 3 to 5 out of 20 measurements in each run. I have run the script in the current configuration 7 times.

In any case, I was able to get a 2 hour trend of the ESD charge. See ETMY_Charge_Trend_9Jan2015.pdf. The charge wanders a bit, but has some consistency.

The charge measuring script is:

.../SusSVN/sus/trunk/QUAD/Common/Scripts/ESD_UL_LL_UR_LR_charge_07-H1.py

The analysis script, which I am still updating for LHO is:

...SusSVN/sus/trunk/QUAD/Common/Scripts/ESD_UL_LL_UR_LR_analysis07_BrettTest.m

A lot of work has been done on HAM3-ISI for the past month. I'm trying to summarize here what we know and which path we should follow.

Situation before the SEI meeting

. We see a high Q peak around ~0.65Hz in all the local sensors (GS13+CPS) and all the DOFs, except RZ.

. This peak is present only when the Z sensor correction is ON. It doesn't matter if the Z sensor correction is coming from HEPI or the ISI, the peak is present when one of them is ON (see here and here). It doesn't seem to have any link with the X,Y sensor correction.

. The peak seems non-stationary. First of all, the peak is not the same if the sensor correction is done with the ISI or HEPI (see first attachment). Second of all, the amplitude and frequency of the peak vary with time (see second attachment and here).

Progress made

. The problem doesn't come from the ground STS. We checked the electronic chain (swapping distribution chassis) and tried another ground instrument (see here). The problem is independant (see here).

. This is not mechanical/rubbing issue. We did a driven transfer function around this frequency with a perfect coherence/no sharp peak.

. The problem doesn't come from HEPI. We turned OFF the HEPI loops with no improvement (see here)

. We don't think it comes from a specific sensor. Everything looks fine wihtout sensor correction, plus the problem shows up in all the sensors (if it was , let's say, a CPS issue, it wouldn't appear in the GS13).

. It might come from the blend: by switching to a 750mHz blend, the peak seems to disappear. However, we know that the 750mHz blend is obsolete, so I wouldn't draw solid conclusions from that...

. It might come from the drive (see here)

New situation after the SEI meeting

Now it seems that the peak appears even when the sensor correction is OFF (see third attachment)! I don't know if it's a good or bad thing, but that's the first time we've seen that. The only thing I did this afternoon is switching blend filters on all DOFs and turning the Z sensor correction ON and OFF... The ground motion doesn't seem any different than usual.

Action item for Sunday

. Keep investigate to see if the sensor correction is the cause of this peak

. Implementation of a slighty different blend in Z to see if it makes a difference.

. PR2 and MC2 have a mode at 0.67Hz. Could it be a weird coupling between the sensor correction and suspension? We'll try to turn the damping loops ON and OFF to see if it makes a difference

. The ISI model has been restarted before, but we haven't tried to restart the actual computer

Since we rolled out the sensor chains from our investigation (I'll do a summary alog about that in a minute), I've looked at the actuation chain.

I took the transfer function between the actual ouput of the actuators (counts) and the related voltage read by the coil driver readback channels. This is the same information in different units, so except some color coming from the electronics, we shouldn't see any sharp peak in the transfer function. I did this exercise on HAM3 (HEPI Z sensor correction ON and OFF) and HAM2 (Sensor correction OFF) for the comparison.

The results are interesting. First I'm not sure I understand why we don't have a perfect coherence (noise?), but I don't think that's linked to our issue. More interesting, we can see a small peak around 0.66Hz on HAM3 when the sensor correction is OFF (which is not the case on HAM2).

This might be an indication that the problem is coming from the actuators.

With Kiwamu's blessing, I modifed the following LSC common files to ground all unused inputs of filter module with control parts

lsc/common/models/lscpsl.mdl

lsc/common/models/lscimc.mdl

These are common parts, so I have not committed the changes to SVN as this may break l1lsc. There appears to be a mismatch between the sites for these files which I'll let the ISC team resolve.

h1lsc0 now compiles with RCG2.9

The BSC-ISI sensor correction screens were updated based on Jeff's request (SEI aLOG #666). A screenshot of the new screens is attached. A link to the old screens is still available on the bottom right of the new ones. Jeff already gave his approval. I will wait for feedback from the other commissioners before commiting to the SVN.

Work was performed under WP #4998 which remains open so the same changes can be applied to the HAM-ISI and HEPI.

I wrote a script which compares a target's autoBurt.req file against its safe.snap file. This is a channel list check, verifying that the safe.snap has no more and no less channels compared to autoBurt.req. I am not checking channel values or channel read-only-status.

I ran the script on all the H1 models (100 of them). For models I manage (IOP and PEM) I fixed any mismatches.  For any system which was missing a safe.snap, I created one by snapshotting the system.

The end result is that all safe.snaps are concurrent with the exception of:

certain SUS safe.snaps still retain the GUARD channels which were removed this Tuesday, Jeff K is going to resnap these this weekend

h1pslfss.snap is missing some DINCO channels, I'l work with PSL to resolve this

LVEA: Laser Hazard
Observation Bit: Commissioning  

08:00 Jodi & Rodica – In LVEA looking for IO parts
08:13 Manny – Removing test stand cables from LVEA west bay
08:30 Jodi – Out of LVEA
09:00 Jodi – In LVEA working with Rodica on IO
09:12 Hugh – In LVEA working on 3IFO HAM storage retrofits 
09:18 Elli – Working on IOT2R table
09:20 Mitch – Going to LVEA for HAM 3IFO storage work
09:25 Filiberto – Going into LVEA to help Manny with removing cables from the west bay
09:29 Jodi – Out of the LVEA
10:30 Kyle – At End-X to start vent
10:31 Peter & Rick – Going to End-Y to work on PCal camera focus
10:31 Hugh & Mitch – Out of the LVEA
10:34 Travis – Going into the cleaning area to get tools for End-X vent
11:24 Doug – Checking TCS chiller alarm
11:49 Filiberto – Out of LVEA
11:49 Filiberto – Going to End-Y and End-X to check on TCS equipment
12:00 Electrical inspector on site to inspect work at VPW
12:00 Manny – Out of the LVEA
12:05 Doug – Out of the LVEA
12:08 Jodi & Rodica – Out of the LVEA
12:35 Jodi & Rodica – Going to Mid-Y to check on 3IFO IO parts 
13:17 Filiberto – Back from end stations
13:20 Jodi & Rodica – Back from Mid-Y
13:36 Sudarshan – Working on PCal cameras at End-Y
13:45 Kyle & Gerardo – At End-X working on BSC9 vent
14:05 Corey – Going to squeezer bay
14:40 Kyle & Gerardo – Back from End-X
14:56 Dale – Taking tour into LVEA 
14:57 Bubba & Kyle – Going to End-X to remove BSC9 door
14:57 Travis & Betsy – Gathering tools and heading to End-X for EQ stop work
15:17 Elli – Going to IOTC2R to check on fan noise
15:35 Corey – Out of the squeezer bay
15:43 Betsy – Going to End-X for Quad EQ stop work

Conlog searches unavailable for duration.

The TFs I took this morning show that the rubbing is back on the ETMx main chain now that we are back down to 7 Torr in pressure.  The rubbing TF looks exactly like the rubbing TF we had before I opened up the gap of the EQ stops around the test mass.  While we knew that the rubbing could have been possibly due to the barrel stops around the test mass OR the PUM mass above the test mass, we assumed it was specifically the stops around the test mass since those were the only ones adjusted during the Dec vent.  I did not check the PUM stops (or any other stops further up the chain) yesterday.  Darn it, I should have!  The temp+buoyancy effect is the same on the PUM as it is on the Test mass, so the gap of the EQ stops should be bigger around the barrel there too.

So, we are re-venting today to now:

- Inspect other EQ stops, look for outliers in gap settings further up the main chain

- Open up the gap around the barrel of the PUM to the 1mm (top stops) and 1.5, (bottom stops)

We'll employ the same stripped down version of the entry/exit checklist as yesterday, namely to inspect and DI Nitrogen blow the HR face of the ETMx on the way out.

The reaction chain TFs continue to look healthy, so no problems there.

The sensor correction is installed and ON on all the chambers, but with a nominal matching gain of 1.

I made a small script to calculate the correct matching gain for X, Y, Z. The script works only for the HAM-ISIs for now, but it will be pretty easy to adapt. What it does:

- Grab the ground seismometer and GS13 data in X, Y, Z.

- Calculate the ASDs and calibrate them in m/rt(Hz).

- Calculate the GS13 over Ground ratio.

- Take the mean of the ratio for a [0.1Hz 0.4Hz] bandwidth.

Before running this process, the ISI needs to be in High blend mode (750mHz) on all DOFs with sensor correction OFF.

I've done this exercise for HAM4-ISI. The numbers seem a little small (Gain for X: 0.8784, gain for Y: 0.8702, gain for Z: 0.8574) but brings some improvement (see plot attached).

This has been done during the day, we might want to do it overnight for better tuning.

I'll do the other chambers ASAP. The script that I made is for now commited in the HAM4 folder of the svn:

/ligo/svncommon/SeiSVN/seismic/HAM-ISI/H1/HAM4/Misc/gain_matching_calculation.m