Maybe moot, because it looks like there might be problems with an OM, but the ISI looks ok. I took tf's in DTT, and they look similar to measurements taken under vacuum. HEPI is still locked, not sure of the state of the optics, but the ISI doesn't seem to care much. See attached.
J. Oberling, S. Doravari
With the HAM6 activity closing out, we took advantage of the window and tweaked another laser and swapped it into SR3. The SN of the new laser is 199. This was installed in the SR3 optical lever so we will have data for a direct comparison between the stabilized diode laser here at LHO and the fiber-coupled HeNe in use as the LLO SR3 optical lever. We will begin monitoring this laser tomorrow after it thermally stabilizes overnight so we can perform, if necessary, final tweaks to the laser power to finally stabilize the laser.
Just attaching images associated with this work.
1) SR3 Oplev laser currently installed is Sl. No. 199
2) The binary switch state for setting gain and whitening. Currently there is just 3dB of gain and no whitening
3) power spectra of adc noise floor and sum signal to show that the signal is atleast ten times larger than the noise floor at all frequencies of interest
It seems there is a discrepancy between the SR3 pitch slider and the SR3 oplev motion. I move the pitch slider by what I think is 0.5 µrad, and the oplev reports that SR3 moves by 0.2 µrad. Not sure about yaw.
Daniel, Jim, Dave:
Following our discovery yesterday that the LSC receive errors of ISC RFM IPC data was zeroed when the ASC computer was removed from the RFM loop, this afternoon we changed the h1asc.mdl model to remove the 16 obsolete RFM channels to see if that changed the LSC error rate. It did, it has zeroed it. The attached strip tool plot shows the LSC error rate for the 4 ISC RFM channels (2 per end station). The ASC change was made at the 35 minute mark in the 1 hour long X-axis. I have a cron job running on sysadmin0 which clears the errors every minute, the strip tool is updating every 15 seconds.
This is a temporary band-aid fix for the LSC. If we were to put the 16 IPC channels back into the ASC (8 per arm) the error will re-appear. We will attempt to reproduce the error on the DTS and work at a long term solution.
Here are the ASC sender RFM IPC channels which were removed. I verified that no other model is showing RFM receive errors, confirming these are senders with no associated receviers.
H1:ASC_PZT[1,2][X,Y]_[PIT,YAW]_ISCE[X,Y] 8 in total
H1:ASC_ISCE[X,Y]_QPD[1,2]_[PIT,YAW] 8 in total
After the ISC crew were finished, Jim unlocked the ISI and made a small adjustment to it's balance. I wiped a few of the surfaces of the ISI and chamber that I could reach near the door. I placed a witness plate on the ISI table in the middle of the sea of ISC mirrors nearest the east side of the table. Kyle, Gerardo, Bubba and I then tacked the door on with 4 bolts. Kyle turned off the purge air. Dan/Keita and Jim are running OM/OMC and ISI TFs to see how we fair for pumping down tomorrow. We're not yet out of the woods. TBC...
PS Particle counts at the door interface while the door was going back on was
0.3um 10
0.5um 10
1.0um 0
Here's a picture of the HAM6 table as viewed from the end (East) door. The new CC wafer is now inbetween the sea of mirrors/BDs/TTs.
07:50 Jeff B. to HAM6 08:00 Daniel S. restarting h1lsc model, errors 08:12 Daniel S. restarting h1ecatc1 08:41 Elli and Nutsinee to end Y 09:13 Rick, Travis and Sudarshan to end Y to work on PCAL 09:25 Filiberto and Koji to HAM6 to check grounding 09:31 Rick to end Y 09:34 Peter K. to H2 PSL enclosure 09:38 Hugh de-isolated HEPI on HAM1, going out to check clearances 09:52 Jeff B. to 3IFO storage area to put optics in the desiccant cabinet 10:03 Hugh back 10:12 Betsy to HAM6 10:18 Jeff B. done 10:20 Karen to mid Y, Cris to mid X 10:49 Jeff B. to HAM6 to check on dust monitor reporting low battery alarm 10:55 Jeff B. back, dust monitor plugged back in 11:01 Richard to LVEA to check on Filiberto 11:08 Richard back 11:12 Karen leaving mid Y 11:30 Koji and Filiberto out, found short 11:44 Peter K. out of H2 enclosure 12:12 Greg G. turning on TCS X laser 12:47 Tour in CR 13:18 Elli and Nutsinee back from end Y 13:31 Rick, Travis and Sudarshan back for lunch 13:32 Hugh reisolating HAM1 13:33 Richard to LVEA to look at dewpoint sensor and check on Filiberto 13:50 Elli and Jeff running excitation on etmy 13:54 Jeff and Elli stopping etmy excitation, starting etmx excitation 13:56 Jeff stopping excitation on etmx 14:13 Peter K. transitioning LVEA to laser safe 14:21 Richard to LVEA to look at dewpoint sensor and check on Filiberto 14:36 LVEA transitioned to laser safe 14:42 Richard back door being tacked on 14:54 Elli and Nutsinee to end X 15:25 Dave restarting ASC model 15:36 Jason and Suresh replacing SR3 optical lever laser
Looking at the RF distribution system for corner and end stations there are only 3 units which show an error:
There is also an error associated with the green WFS demodulators where the hardware for the readbacks is still in the works.
The 90MHz demod problem was traced to a crosswiring of the demod readbacks of ASAIR_A and ASAIR_B. Decided to swap the DB9 cables.
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.
Re Linearity & ROM. Looked at V3 and V4. From the free hanging position, it appears the platform is hanging low at V4 and the Actuator Plate will run into the Bellows Shield hence the low V4- ROM. To fix this we'd have to get on the Big DSCW Springs and raise the platform. I think the install process needs to change to ultimately address this: after Initial Alignment, run ROM and excitations etc. letting the platform settle to its ultimate resting place. Raise the platform with the Springs and repeat until it sits where we want.
For V3, remember, the slope on the Linearity plot appears to roll over at the positive side of the curve. I checked and although V3 also hangs low like V4, this is a positive (up) issue. Looking closely, the top of the Foot at the back rib looked pretty close to the notch in the Rear Caging Brace. For a vertical motion, this contact would be a glancing impact and the Foot could shift sideways and get further vertical displacement. I raised the Rear Caging Brace and reran the Linearity measurement. See attached and compare with the above plot. The slope is restored and shows no roll over. Nice when something works as expected.
Given the magnitude of these tests and the actual motion we need for ops, these interferences would not have impacted performance. However, we could over time possibly walk the platforms to a point where it does matter.
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.
[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.
Regarding 90:10 BS, note that a thicker 2" Siskiyou lens holder instead of mirror holder was used, as was the case at LLO.
Since we have 36 dB less power on the ASAIR diodes, I have compensated for this in the ASAIR RF filter modules.
ASAIR_RF_90 had 18 dB of analog whitening gain. It now is maxed out at 45 dB, and there is 9 dB of gain inserted into FM8.
ASAIR_RF_45 had 6 dB of analog whitening gain. It now has 42 dB of analog whitening gain. Since we are going to remove the ND filter in front of the PD, this will have to be redone.
In both cases I also retuned the dark offsets.
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
We were going to wait until we had a year of data before putting in corner station plots and the plots for tilt perpendicular to the beamline, but since Krishna asked, here are the CS plots for the same storms as Fig. 3.
Thanks for the study! I know it is very time consuiming but I thought I'd say that it would also be very interesting to compare the tilt of the corner-station against the end-station during these wind-storms. If I remember right, the corner station slab moves roughly factor of 2-3 less than EX. If so, then once tilt at the end-station is corrected for (by factors of 5-10), the corner-station tilt would limit the low-frequency ISI motion.
Added Figure5 showing 4 months CS-X and CS-Y tilt plotted against wind speed measured at EX.
Added four new figures which are Figures 2,3,4 and 5 above recast with their y-axis converted from 0.03-0.08 Hz band velocity in [nm/s] into tilt [nrad] using the model from Figure1 (replotted and attached in this comment). Note that x and y in the fit equation and model of Figure1 are in the units of nm/s and nrad, respectively.
