Looking at the RF distribution system for corner and end stations there are only 3 units which show an error:

• The RF divider for the 40MHz indicates a problem with the power supply. After swapping some cables this was traced to the RF Amp concentrator where channel 1 seems busted.
• The RF amplifier for TCS where the field cable is missing.
• The 90MHz LO for ASAIR_B which indicates no signal.

There is also an error associated with the green WFS demodulators where the hardware for the readbacks is still in the works.

When Fil was checking for electrical shorts on HAM6 after the ISC work, he found one of the ISI actuator cabels was shorted to the chamber. Before I went in chamber to unlock and rebalance the ISI, I checked the cable and found that the V3 actuator cable was plugged in upside down. I flipped the cable, Fil checked the pins again, the cable was no longer shorted. 

[Fil, Keita, Dan, Koji]

The ISC tasks in HAM6 was all completed.

Ground short check

FIl and Koji checked the ground short for ISC, SEI, and SUS. We found the shield of the OM1 TT cable had shorting. Also one of the ISI coil driver cables on D4-2B feedthrough had a shorting.

Resoution for the OM1 TT shield shorting

We went to the chamber again and check the shorting for the OM1 TT. The shield for one of the quadrupus cable was touching the table.
After a light touch, the shorting disappeared. We scurptured the shape of the cable such that this shorting won't happen spontaneously and
the beam is not blocked by the cable at the same time.

Picomotor check

The function of the 10 picomotors on HAM6 were checked. They are all good.

Fast shutter function check

The fast shutter test was done and it poped up and down although the response time of the shutter should be checked again
once the beam is back wtih vacuum pressure. Note that we retreated from the chamber to activate the HV for the fast shutter.
And the HV is deactivated again after the test was done.

Beam diverter final test

We doubly checked if the BDs moves or not. We found no problem.

Daniel, Jim, Dave:

Daniel restarted the h1lsc model this morning, but it did not run. The reason is that its safe.snap file is missing from the target's burt directory.

I have created a symbolic link from

/opt/rtcds/lho/h1/target/h1lsc/h1lscepics/burt/safe.snap

to

/opt/rtcds/userapps/release/lsc/h1/burtfiles/h1lsc_safe.snap

The latter file is under SVN control, last modifed Friday 13th March.

I have also noticed that h1calex and h1caley models are also missing their safe.snap files.

GV5 spontaneously hard closed -> ~26 hours after 10psi soft-close -> This valve has done this before at 15psi 

A

Yesterday ran Range of Motion and Linearity Tests.  Took Spectra as well and then ran TFs overnight.

For the ROM, which evaluates based on the free hang position, not from zero, H1- was limited to 0.8mm.  This is not necessarily running into anything as the sensor (IPS) was just running into the sensor max.  In other words, the sensor position could be adjusted (along with the cartesian Isolated-to position) if the true centering of the Actuator could tolerate that.  Also for V4-, it was hitting something and the range was limited to 0.7mm.  I have not investigated this.

The linearity tests are possibly within spec (don't have a number of what that should be) but here V4 is also an outlier having a lesser slope than the others.  See attached, V3 also looks weird here but the range of motion is fine for V3 which drives further than the linearity test so if it is running into something it must be compliant.

The new L4C looks good though.  Attached are Spectra from last October and Yesterday.  I collected Isolated spectra yesterday and the data from October is 'Undamped' but the improved health of this L4C is apparent.  I can get Isolated from a few days ago before the swap.

TFs to come.

I came in early to finish the model changes started yesterday. First, I restarted the LSC front-end. This failed with the error message "-1 Operation no permitted". Being stumped, I decided to restart the DAQ to update the channel list for the end stations ALS systems. This worked fine as far as the DAQ and the ALS systems were concerned. However, it also crashed sush2b with an IRIG-B error! At this point the DAQ overview screen looked like a Christmas tree. I am amazed.

The h1lsc model would not restart and needed to have the burt restore button pushed (which is no longer on the GDS_TP screen).  

The data concentrator had been restarted earlier, which caused the mx_stream to fail on h1susauxb123. Restarted the streamers on the front end and the data was restored.

There was a large IRIG-B timing error on h1iopsush2b, so I restarted the models on the h1sush2b computer.

HAM6 in chamber work
Check grounding and fast shutter, transfer functions

SEI
HAM1 L4Cs replaced, looking at transfer functions
New isolation filters tested, not ready to leave in

CDS
LTS humidity sensors cabling

Jeff B. moving optics into desiccant cabinet

RFM errors investigation

Jim, Dave:

during the Ham6 vent, we further investigated the LSC RFM receiving errors. We remotely bypassed several nodes in the Y-Arm RFM loop (except for the h1iscex sender and the h1lsc0 receiver). We found that the Y-Arm errors disappeared when h1asc0 was bypassed. We then bypassed h1asc0 on the X-Arm loop and ran for 50 minutes without a single LSC receive error (error rate is typically 50 per hour).

Bottom line, h1asc0 is somehow causing the ISC to LSC errors. We found that of the 16 RFM channels the ASC is sending per arm, only 8 have receivers. Clearly we should start by removing the 8 obsolete senders (per arm, 16 in total). We have scheduled this with Daniel for such time as when the DAQ can be restarted.

We are investigating this further on the DTS.

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 optimal location for  a single version of Krishna’s BRS (intermediate frequency tilt sensor), or, if it would be better to have two of them, depends on the tilt spectrum in the beam direction. We suspected that wind-induced tilt is worse at EY than EX, where the BRS is currently located, because, for typical wind storm directions, the building is being pushed roughly along the beam axis at Y-End and roughly perpendicular at X-End (the tumble weeds usually roll down the Y-Arm). But we aren’t sure whether a single sensor at EY would make sense (e.g. if EY is 10x worse than EX) or if two BRSs would be better.  Since we have only the one BRS, we used the 0.03-0.08 Hz band of STS seismometers to compare the two stations. This frequency band was selected as a proxy for tilt because this band is below the microseismic peak frequency and, in windy conditions, ground motion in this band is usually dominated by tilt. Figure 1 shows the strong correlation between the 0.03-0.08 Hz seismometer band and the tilt measured by the BRS at EX for one wind storm. Each of the small points in the plots in this log represent a 60s average of the wind speed and a 60s fft of the ground motion.

Figure 2 shows 4 months (Aug 15, 2014 - Dec 15, 2014) of the 0.03 to 0.08 Hz beamline seismic band at EY and EX plotted against wind speed measured at EX.  The large red and blue dots show the median of minute points in 2 MPH bins. Dipongkar has plotted the median because large earthquakes, which also appear in this band, would bias the mean. Roughly speaking, for a particular wind speed, the signal at EY is twice the signal at EX when averaged over many storms in 4 months. This data suggests to me that we may want a second BRS at EY rather than moving the sensor from EX to EY, because the difference is, on average, only a factor of 2.

The differences between the stations can change for different wind storms, possibly because of different wind directions. Figure 3 shows the effects of individual storms (each storm is a different color, the same color on both plots) at the two stations. One of the storms produced about 5 times more beam-line tilt at EY than at EX.

Caveat: Getting this data is very time-consuming, so we are putting in this log even though we have obtained only 4 months of data. Dipongkar will continue to increase coverage to include the spring windy period and we will update if necessary.

Robert Schofield, Dipongkar Talukder