Jim and Dave:

we added a new front end to the DTS, the x1iscex system. This completes all nodes on the DTS X-Arm RFM IPC loop. We will now see if we can reproduce the H1 LSC RFM errors on the test stand.

the x1iscex will also be used to make noise measurements using the new IO Chassis DC power supply board. For this purpose, an AA-Chassis was installed above it.

[Dan, Ross, Corey, Keita, Koji]

The ISC work for HAM6 was done mostly along with the procedure in this ALOG entry 17631

We first started from the steps which does not require the laser beam, and then moved on the steps with the beam.

Visual inspection of the fast shutter mirror

- The mirror on the fast shutter was checked. We confirmed that the mirror is well intact and did not show any sign of delamination.
i.e. The toaster does not seem to fly.

Beam diverter lubrication with Krytox LVP

- The two beam diverters (BDs) were removed from the table after marking their positions with dog clamps.
  Corey applied Krytox along with the procedure by Matt H.

- The additional mass is added to the moving element to ensure each BD flips to the ends of the moving range.

- The BDs were returned to the HAM6 table. Their positions were aligned in the later process.

- The motion of the BDs were confirmed with EPICS I/F.

QPD cable strain relief

- QPD cable strain relieves (D1101910&D1101911) were installed to AS_C/OMCR_A/OMCR_B DCQPDs.
Now there is no chance for their ferrules to touch metal parts around there.

Transition to Laser Hazard

- The input power at this point was ~3W.

Initial alignment

- Aligned the beam on the AS_C QPD with SR2
- Aligned the beam on the OMC QPDs
- Confirmed the beam is on the WFS QPDs

OM1 mirror replacement

- The hIgh transmission (T=5%) OM1 mirror was removed from the TT suspension.
- The new OM1 mirror with T=800ppm (E1100056 Type02 s/n15) was installed.

- The old and new mirrors were supposed to have the same dimensions. However, the mirror holder faced down significantly.
  This was actually the same situation as it was seen in LLO.

- I don't want to describe the detail of the TT story. In the end, the clamp units on the mirror mounts were shifted towards the face.
  This let us recover the proper alignment of the OM1.

- The alignment slider values were coarsely debiased by aligning the TT suspension structure.
- All the BOSEMs indicated that the flags are too deep inside the BOSEMs. This was fixed.
- We actually debiased the suspension at the end of the procedure again.

- The AS AIR/AS_C pathes were aligned. The beam was faint and we decided to inclease the input power to the IMC up to 7W.
The beam was aligned to hit the AS_AIR periscope mirror. The AS_AIR beam on the ISCT6 table should be aligned.

- The BD for AS_AIR was aligned. The reflection of the BS was also aligned.

90:10 BS insertion

- A 90:10 BS (E1500009) was installed in the OMCR path. In order to accommodate this new optic, the steering mirror just in front of this BS
was moved back towards the OMC. We made sure the beam is hitting the OMCR periscope mirror. This changes the angle of the beam on
the ISCT6 table. Therefore, the OMCR beam on the ISCT6 table should be aligned.
- A V-beamdump is installed for the reflected beam of this BS.
- The OMCR QPD sled path was realigned.

Power budget

- The optical powers at the various places on the table were measured. Also the AS_AIR and OMCR powers on the ISCT6 were measured.
These measurements allows us to estimate the optical powers in the chamber using the ones on the ISCT6 table.

Double checking

- The optical path was traced from the septem windows to the OMC, AS_AIR, AS_WFS, OMCR paths.

- The shutter mirror was lifted manually to see if the reflected beam is still properly dumped.

- Took photos of the table for updating the table layout.

Contamination control

- At the end, the partice level was checked in the HEPA booth. It shows 0 counts for all particle sizes.

Still to do before closing the door

- It should be checked if the picomotors and fast shutter are still working.

- It should be checked if there is any ground shorting.
Note that BDs are shorted on the table. Also the cable harness on the OMC shorts the shields of the OMC QPD/DCPD cables at the OMC breadboard.

The malfunctioning RF driver on the TCS Y table was swapped today. Unit 210020-20710 was replaced by 208160-20510 which is now coupled with the 20306-204190 laser. A quick test showed > 50W while in pulse width mode. 

TCS X table had the AOM swapped to the Kepco power supply. Both AOMs are now powered from the Kepco power supply and are running at 25V. The X AOM continued to show a fault after it had been turned on, but unplugging and replugging it at the feedthrough cleared the problem  A quick check showed no significant changes in alignment. I'd like to make sure the rotation stage is still behaving like before. 

The laser power feedthrough on X was also bypassed like on the Y table from last week's work.

Dan & Koji

We've finished most of the ISC work in the HAM6 chamber. Details are coming later.

The left-over ISC items are:
1) Cable ground short inspection
2) Checking  functionarity of the picomotors and fast shutter.

These should be done tomorrow before closing the door.

The PSL rotation stage was energized again.
The laser power incident on the IMC was returned to 2.8W.
The PSL laser shutter between PSL and HAM1 is closed.
But technically to say, the LVEA is still laser hazard until it is declared to be safe.

J. Kissel, J. Warner

In summary -- in the "windy" configuration that includes the BRS (described below) we can achieve better performance, as measured by the local T240s, than when just switching to 90 [mHz] blends at almost all frequencies. This is especially true in the 20 to 80 [mHz] band, where ALS lock acquisition is limited by end-station VCO range. In this study, the wind is a consistent 10-20 [mph]. Not necessarily "high," so we'll still need more data during those conditions to confirm if there's an upper limit to performance improvement, i.e. if / when the BRS saturates and it's corrective signal becomes detrimental to the platform motion.

Discussion & Details
---------

I took some more data with H1 ISI ETMX in several configurations, looking to supplement Krishna's data on the performance impact of the BRS during 5-10 [mph] winds (see LHO aLOG 16465), this time with a confirmed consistent wind of 10-20 [mph] and a more-typical ground translation from the microseism. Further, since Krishna's study, Jim, Hugh, and I have made significant improvements to the BSC-ISI performance from beating down unexpected noise sources (see e.g. LHO aLOG 17702, Integration Issue 1004, LHO aLOG 16818, etc.) the results are considerably less confusing. This also serves to show what we get when we'll eventually automate switching between these configurations (see LHO aLOG 17639).

I compare three different configurations of the ISI's ST1 X DOF sensor correction and blend filters, over a short, 2-hour window where X-End wind has a consistent, minute-trend, mean of 10 [mph], and a consistent, minute-trend, max of 15-20 [mph]. The three configurations of the ISI's ST1 X DOF are as follows:
(1) Nominal -- 45 mHz blend; DeRosa's 0.43 Hz only, narrow-band, sensor correction (NB SC); GND T240 alone used for sensor correction, no BRS
(2) Windy when BRS doesn't work -- 90 mHz blend; DeRosa's 0.43 Hz only sensor correction (NB SC); GND T240 alone used for sensor correction, no BRS
(3) Windy with a functional BRS -- 90 mHz blend; Mittleman's broad-band, low-frequency, sensor correction (BBLF SC); Tilt is subtracted from the GND T240 with the BRS, and the super sensor is used for sensor correction.

Recall that plots comparing the X direction 45 and 90 mHz blend filters can be found in LHO aLOG 17595.

Comments:
- Look at 2015-04-07_H1ISIETMX_SensorBlend_Config_Comp_X.pdf first. This shows the X direction.
   PG1: Performance of configuration (1) has a significant amount of gain peaking (about a factor of 4) from the 45 mHz displacement sensor blend filter from 25 to 80 [mHz], as expected. This the sacrifice made to get the awesome performance between 0.1 [Hz] and 0.4 [Hz]. When we move the blend frequency up to 90 mHz, to configuration (2), the factor-of-four gain peaking moves up as well to 40 to 120 [mHz]. However, this shift up an overall RMS displacement reduction of about a factor of 5. In doing so, we lose a factor of 10 in performance between 0.1 [Hz] and 0.4 [Hz], and also some loss between 1 to 10 [Hz]. In configuration (3), The BRS+STS super sensor coupled with the broad-band sensor correction allows us to claw some of that performance back, *and* reduce the gain peaking to essentially zero.
        The trouble with interpreting ASDs is that the contain in coherent noise of the platform as well. Of course (save where the measurement is readout noise limited) this is the real motion of the platform, but it's less easy to see what's going on. Hence, 
   PG2: Comparing the coherent, linear transfer functions in each state, we see much more clearly what's going on: configuration (1) has x4-5 gain peaking between 25 and 80 [mHz]. One might even argue that we could tune the narrow-band sensor correction better, because it's performance is best at 0.35 [Hz] instead of 0.43 [Hz]. When we switch to configuration (2), the performance follows the change in displacement sensor filter, as expected. Finally, in configuration (3) we're basically blending in the tilt-free, inertial ground super sensor at 20-30 [mHz]. So we win back all of the noise introduced when the noisy displacement sensor is used out to high frequency, and in the 0.1 to 0.4 [Hz] band, we're only at most a factor of 2 to 3 away from the best nominal configuration. In fact, the performance is *even* better than the nominal configuration between 0.4 and 2 [Hz].

- Now look at 2015-04-07_H1ISIETMX_SensorBlend_Config_Comp_X_SensCorrSignal_ASD.pdf
    Unfortunately, we don't record the pre-sensor corrected, calibrated, Cartesian displacement sensors. In fact, there isn't even a test point for these channels. As such, there isn't a good way to compare the performance of the NB SC filter and the BBLF SC filter, using the CPS. As a proxy, I took a look at the output of the sensor correction path, just *before* it's subtracted from the CPS. The two signals should be equivalent to the CPS in the band that we use the sensor correction modulo a sign which doesn't affect the ASD. We can see that Configuration (3) has the *least* amount of sensor correction request below 0.1 [Hz], because the BRS has subtracted out the tilt from the GND T240 of this region.

- 2015-04-07_H1ISIETMX_SensorBlend_Config_Comp_RY.pdf shows the RY direction.
    PG1: Shown merely to demonstrate that the ground tilt ASD was essentially the same for all three of these measurement configurations, as was the residual tilt of ST1.
    PG2&3: Shown because I can -- the transfer function between ground tilt and platform tilt. Because we've reduced the HEPI pump servo noise (II 1004) we see now that the platform's RY motion is limited by and coherent with ground RY below 0.2 [Hz] as originally expected. Good!
    PG4&5: This is the transfer function between ground tilt (RY) and platform translation (X). It's pretty scary, but I'm not sure I trust it. I'm not at all confident that DTT is able to handle calibrating the transfer function between these two correctly. Anyways, I include it, again, because I can. Aside from the magnitude, pg 5 does clearly show that platform X is coherent with ground tilt.

This data set settles the question of whether the configuration (3) is better than (1) in 10-20 [mph] winds, especially if just going to configuration (2) during these kinds of winds is enough to lock the IFO. Now we just need to perform the same study at even higher winds. Looks like this Saturday may be a good candidate!

The template and all of the plots for this entry live under
/ligo/svncommon/SeiSVN/seismic/BSC-ISI/H1/ETMX/Data/2015-04-07*

Nutsinee, Aidan, Elli

Today we worked at both end-X and end-Y, working on moving the HWS camera to the image plane of the ETMs.  In the morning we were at EY and in the afternoon we were at EX.  We were planning to make only a small adjustment to the HWS location, but after taking some measurements we decided that we will have make bigger changes to the HWS path.  Most likely we will move the lenses on the HWS path.We have measured the current optic locations and we plan to move the HWS lenses tomorrow.

Details:

We located the image plane by applying a 0.05mHz, 2 microradian yaw to H1:SUS-ETMX/Y_M0_OPTICALIGN_Y_EXC .  We took 200 images with the HWS camera at .5 second intervals.  The images are located in /ligo/home/eleanor.king/HWS_Pictures/HWS_image_plane_X and /ligo/home/eleanor.king/HWS_Pictures/HWS_image_plane_Y.   We plotted the centroid of the beam vs time the images using the script 'find_image_plane2.m', which is attached.  We need to move the camera to where the centroid of the beam moves by and amplitude less than 0.2 pixels.  With the current lens locations, we would need to move the cameras by ~0.5m, which we don't have the room to do.  Instead we plan to move the lenses on the HWS table to move the conjugate plane.

Curernt HWS optic locations:

EY table layout with optics names as per https://dcc.ligo.org/D1400241
-All units are in cm.
-M3 was measured from the back face of the optic.
The distances between the optics at EY are:
BS1:M1    10.7 (cm)
M1:L1       7.7
L1:L2        61.0
L2:M2      12.3
M2:M3     9.6    
M3:M4     82.5
M4:M5     6.3
M5:L3      8.5
L3:M6      55.9
M6:CCD1 33.9

----------------------------------------------------

EX table layout is not the same as that in https://dcc.ligo.org/D1201448.
-  The lenses L1 and L2 are in different positions.  L1 is between M1 and L2, L2 is between L1 and M2, L3 is as drawn in D1201448.
-All units are in cm.
-BS1 is measured from the front face.  BS2 is measured from the back face.  M5 is measured from the front face.
The distances between the optics at EX are:
ALS-M11:BS1 6.5 (cm)
BS1:M1      32.7
M1:L1        10.6
L1:L2          62.6
L2:M2         20.1
M2:BS2      11.3
BS2:L3        62.9
L3:M3         11.2
M3:M4        10.2
M4:M5        63.3
M5:M6        31.1
M6:M7        9.9
M7:CCD1    11.5

The tidal code has been changed by adding a delay trigger to the red lock trigger and by requiring a lock condition to go into the red lock state. This should avoid the problem where the tidal state machine keeps switching states upon cavity flashes after a lock loss.

Prepared a change in the LSC/IMC model to enable the common tidal from MC_F using a switch after the MC_F filter module. This way we can switch on the common tidal feedback independently when the tidal state machine is in the transition state.

New slow controls code was loaded into the remaining EtherCAT systems to support automatic screen generation.

A new feature was added to the auxiliary library to allow momentary switching of its binary outputs. This has been implemented for the ESD power on/off channel to avoid the problem with the 4 second auto-reset when the channel was left in the high state by mistake. A high transition will now generate a one second long pulse which returns to low automatically.

Scott L. Ed P. Chris S.

Relocated lights and equipment to X-1-8 double doors north towards mid station yesterday.

Tested 8 sections as opposed to the normal 6 as this is the last and somewhat longer section from the double doors to mid station. Vacuumed beam tube supports and cleaned those same floor areas. Heavily soiled areas.  Able to clean only 6 meters yesterday and 64 meters of tube today.
Beam tube pressures monitored by control room operator during cleaning operations.  

(Kyle, Gerardo, Bubba, Jeff B., Betsy, Richard M.)

Kyle -> Soft-closed GV5 and GV7 

Kyle, Gerardo -> Connected pump cart to HAM5 annulus -> Vented HAM5/6 annulus volume 

Kyle, Gerardo -> Vented HAM6

Richard M. -> Troubleshot and fixed cabling to PT110A 

Kyle, Gerardo, Bubba, Jeff B., Betsy -> Removed HAM6 East door

8:05 Kyle closing gate valves in vertex

8:10 Gerardo to LVEA assisting Kyle

8:12 Jim loading new isolation filters on HAM 2,3,4

8:21 Fil to EX, EY working on OpLev wiring

8:25 Vern and Richard to LVEA

8:28 Doug to LVEA OpLev test bed, moving to EX

8:33 Elli to EY HWS work

8:33 Jeff B to LVEA dessicant cabinet work

8:35 Hugh to HAM1 for L4C work

8:48 HAM6 picomotors shutdown for vent

9:20 Peter K to H1 PSL enclosure with Corey

9:31 Richard to LVEA checking Pirani gauge

9:33 Jeff B done

9:43 Vern out

9:49 Porta potty service on site

9:49 Betsy to LVEA

10:02 Jeff B to HAM6

10:13 Corey out

10:20 Hanford FD to LVEA

10:27 Cris and Karn to ends

10:52 Koji, Dan, Ross to HAM6

10:54 OMC and OMs to SAFE, HAM6 ISI to OFFLINE

10:55 PR3 light pipe install and align

11:01 Andres to West bay

11:05 Peter K done in H1 PSL, moving to H2 PSL

11:08 Andres done

11:37 Peter K done

11:58 Doug and Jason done at PR3 OpLev

12:03 Hugh done

12:05 HAM6 open for business

12:07 Elli done at EY

12:20 Dan, Koji, Keita, Corey to HAM6

12:37 Fil installing dewpoint cabling LVEA

12:47 Elli to EX for HWS work

12:58 Betsy to HAM6

13:08 Richard to LVEA

13:09 Betsy out

13:33 Sudarshan to EY for PEM work

13:40 Jeff B to HAM6

14:30 Doug and Jason to EY for OpLev work

14:45 Fil to LVEA retreiving tools

   Attached below are the particle counts taken during the removal of the HAM6 East door. Counts were in line with expectations and in chamber counts below expectations. Checks with people working in and around the chamber all showed to be below the clean-100 levels. Last counts taken in the chamber this afternoon showed 10 0.3 micron and 0 for 0.5 and 1.0 micron particles. 

Checked the crystal chiller water level as per the OPS Tues. checklist.  Noted that it was filled on 4/3 (by Peter K, I assume) and that the level was midway between Min. and Max. level.  No water added.

Replaced non-functioning L4C (L4-C) sn L41367 with L41365.  Looks okay, will continue testing.

How?  Deisolated platform.  Locked only corner2 foot to Caging brace (oh yeah, had to adjust rear caging brace to proper position) w/ ~5mil + bias from Ready state--the Actuators tend to pull a few mils (5-10) from the nominal shimmed position.  Disconnected Actuator from brackets but did not loosen brackets hoping this would help retain position.  This won't always work.  Shimmed and locked down actuator.  Disconnected Actuator from Foot.  Powered down Pier Pod, dewired, and removed it and the holder bracket (to get access to L4C Clamp bolts.)  Removed the two Horizontal Actuator Adapters.  Loosened the three L4C holder bolts, loosened the two L4C clamp bolts.  Left the L4C leveling shims in place since we really level the holder, not the L4C.  Pulled the L4C and clamped in the replacement.  Rewired to check spectra--looked okay.  Dewired again.  Reversed process: Actuator Adapters, Actuator to Foot (worked nicely, all the bolts went in smoothly,) Bolted Actuator to Brackets (Housing,) rewired Pier Pod.  Numbers look very similar to before.  Unlocked Actuator and removed shims.  Unlocked Foot--position within 200 counts of position before.  Reengaged Isolation, no problem.

Now the position could actually be different but I really don't think by much (a few mils at the worst) and I don't think ISC is that sensitive here.  But, feel free to drive it to where it is needed.

D. Cook, J. Oberling

ETMx

We moved the recently tweaked oplev laser (SN 197) from our testbed at HAM3 to ETMx.  This laser will thermally stabilize over the course of the afternoon, then we will start monitoring it to perform, if necessary, the final tweaks.  While we were at End X we installed the 50 lb. lead damper assembly onto the ETMx receiver pylon.  Due to the laser swap and the damper install, the oplev needed to be realigned, so we did that as well.

PR3

At the request of commissioners we realigned the PR3 optical lever.  While out there, we installed the light pipe support assembly (see attached picture) to keep the light pipe on the receiver from sagging.

I was taking HAM's 2-4 down this morning to install higher gain control loops. HAM's 2 and 4 went down and came right back up. HAM3 refused to re-isolate, and it took a while to figure it out. It turns out that HAM3 is restoring a large pitch (RY) offset, and Guardian is restoring this offset at roughly the same time it tries to engage the horizontal iso loops. When it does this it sends a large tilt to the GS13's and trips the ISI. Eventually I got around this by switching the GS13s to low gain, and the ISI came right up, whereupon I switched the GS13s back to high gain. A couple thoughts:

1. We should restore fewer DOFs on the HAM's. It wouldn't have prevented this particular problem, but the ISI doesn't wander much, the HAM's don't trip often. I also think that the commissioners probably only care about a few angular DOF's (sadly RY on HAM3 is probably one) and keeping  historical  x/y offsets only make isolating/de-isolating the ISI's and troubleshooting more difficult.

2. HAM3 is restoring a 4000 nrad offset. We should try to offload this to HEPI. Isolating and de-isolating HAM3 ISI is made more difficult by servoing to this position because it sends a big tilt to the GS-13s, which see it as translation.

3. If we can't risk shifting this offset, we should add GS-13 gain switching to the HAM's. Hugh found this sent an impulse to the BS, but that only mattered because it disturbed Mich. We only maybe need this on HAMs because of the need to restore ISI angular offsets (which we don't do on BSCs) and we don't need to switch while operating the IFO. The infrastructure exists, the SEI group may need to do a tiny bit of thought about how to implement it. We only need to switch when transitioning to and from isolated.

I reset the accumulated WD counter for ITMX.  It had a count of 389.

Sheila, Evan

Summary

By increasing the gains on the common-mode and IMC boards, we pushed the CARM UGF up to 35 kHz and saw a reduction in the high-frequency noise floor of DARM.

Some further loop tuning is required to make this viable as a long-term change.

Details

Based on Sheila's earlier measurement of the IMC OLTF, we felt it was safe to increase the gain at the IMC error point (both the error signal and the AO) by 2 dB. Then we increased the CARM gain by 6 dB (using the IN2 slider on the CM board). These changes gave a UGF of 35 kHz with 25° of phase. [See plot and zip file.]

This gave a noticeable improvement in the frequency noise as seen by REFL_A 9I, which is currently the out-of-loop CARM sensor. [See plot.]

Consequently, there was a small but noticeable improvement in the high-frequency noise floor of the DARM spectrum. [See plot with red and gold, taken while still feeding DARM back to ETMX.] In the full locking configuration, the noise floor now touches the GWINC curve from 300 Hz to 3 kHz [See plot with purple.]

Obviously this CARM phase margin is quite thin, and we don't want to run like this as a matter of course. In order to win more phase, perhaps we need to look at the IMC loop and the FSS. Peter K last measured the FSS UGF to be 200 kHz with 30° of phase (on the low end of the phase bubble). In comparison, at LLO the FSS UGF is 500 kHz with 60° of phase.

More details

Nominal gains are 0 dB for CM IN2 [the CARM error signal], 5 dB for MC IN1 [the IMC error signal], and 0 dB for MC IN2 [the AO signal].

The gains used here are 6 dB for CM IN2, 7 dB for MC IN1, and 2 dB for MC IN2.

At the start of the evening, REFL_A 9I had no whitening filters engaged and 0 dB of whitening gain. It now has 1 stage of whitening, 21 dB of gain and a −21 dB filter engaged in FM4 (I and Q). There is some saturation during the lock acquisition, but in full lock the I and Q inputs are now at least a factor of 5 in ASD above the ADC noise floor everywhere. I also changed the digital phase rotation from 77° to 90°, as was hinted at earlier.

[Ed. Merilh, Jason Oberling, Doug Cook, Suresh D]

Doug replaced the diode laser at the HAM3 oplev this morning after it was fixed for reducing glitching (SL No. 197) in the optics lab 2.   We wanted to let it settle for a while and reach thermal equilitbrium before adjustting the power level.  We did that around 12:30PM and I checked the results around 4PM.  The laser is still settling down  as seen in the attached plots.  We plan to monitor it for another day.