J. Kissel, H. Radkins, R. McCarthy, A. Pele [remotely]

A brand new T240 has arrived from Nanometrics; the first of several over the next few year to replace our aging GND STS population. Yay, thanks Ken! 

The (order?) number on the outside of the 3 boxes we've received is 53341-2, and the serial number of the instrument itself is 953.

Our plan (eventually) will be to replace the ill-performing ETMX GND STS with this new instrument.
and then take the ill-performing STS and bury it outside to support wind-fend testing a la LHO aLOG 25842, and G1600548.

Arnaud has graciously offered to update the DCC's inventory E1200068. 

For now, I've put the T240 back in its box, and left it with the other two boxes in the shipping-and-receiving area. We still need to figure out the appropriate readout electronics situation, since we'd borrowed from 3IFO the *last* time we used a T240 at EX, and we'll now need both an STS readout (for outside) and T420 readout system (for inside).

Michael, Krishna

Right on cue, winds picked up today and we got a good chance to test out both BRS-2 at EY and BRS-1 at EX. The wind speeds were in the 20-30 mph range during the following measurements.

EY: The first pdf shows the ASD of Ground seismometer (STS-2) and BRS-2 data and the online tilt-subtracted Y super-sensor data. The magnitude of Y ground motion at ~ 50 mHz is 10 microns/rt(Hz) while the tilt-subtracted Y channel is at ~1 micron/rt(Hz). The second page shows three lines - the first is the coherence between the ground seismometer and BRS-2 showing ~99% coherence in 10-100 mHz region. The second is the coherence between BRS-2 and Stage 1 Y and the third is between Stage 1 rX and BRS-2, showing significant coherences between them.

With BRS-2, we modified the damping scheme to have the damping set at Q of ~50 in the quiet state and Q of ~5 if driven up to a very large amplitude state (>5000 counts). We expect that we won't reach this large amplitude state under wind-speeds of < ~60 mph. The Q=50 state seems to not add any additional noise so far. We will do a more detailed analysis on this soon.

EX: The second pdf is for BRS-1, the ground STS-2 and a similar tilt-subtracted X super-sensor. The magnitude of Y ground motion at ~ 50 mHz is ~4 microns/rt(Hz) while the tilt-subtracted X channel is at ~0.7 micron/rt(Hz). On the second page,  the coherence between the ground seismometer and BRS-2 is ~96% in 10-100 mHz region. The coherences between BRS-2 and Stage 1 X and Stage 1 rY is smaller, especially that between rY and BRS-1 near the microseism. This last part is worrisome and I suspect that the rY sensor may have some problems - (I've noted this in the past - see 14426). Jim has promised to help look into this more by designing some high-frequency CPS-only blends for Stage 1. The idea is that by locking the platform as rigidly as possible to the ground, we can calibrate  the on-board rY sensor by comparing it to the ground (match T240 scale-factors). This may also prove useful for all other chambers which can be roughly calibrated by ensuring that the rY signal is small under quiet conditions.

The second minor issue with the EX data is that the coherence of BRS-1 with the ground seismometer data, and hence the subtraction is not as good as it was with the T240. Jeff tells me that this was the least reliable seismometer they had and will be replaced with a T240 very soon. A third issue is that the ~35 mph wind-gusts occasionally triggered the damper at EX. We will increase the large amplitude threshold for this damper, soon.

Summary: The tilt-subtraction at EX and EY is working reasonably well.

   First cleaning and vent prep staging are complete. Dust counts in the HAM6 cleanroom are excellent. They have been below 100 all day, even with the high level of activity around and in the cleanroom. There was one very high spike (18k both 0.3 and 0.5u particles), while there was cleaning going on inside the cleanroom. These cleared quickly after the crew left the cleanroom. Posted below are trends of the HAM6 dust monitor for the past 12 and 24 hours.   

   I did a compassion check of the new dust monitors and my HHPC-6 hand-held. No more than 10 count difference between the two monitors over several samplings.       

Gerardo, Kyle, Chandra

Vented HAM6 this morning, after soft closing GV5 & GV7. Removed all but four bolts from each of three doors. Vent lasted ~ 1 hour.

Averaging Mass Centering channels for 10 [sec] ...


There are 3 STS proof masses out of range ( > 2.0 [V] )!
STS EY DOF X/U = 3.345 [V]
STS EY DOF Y/V = 2.25 [V]
STS EY DOF Z/W = -4.708 [V]


All other proof masses are within range ( < 2.0 [V] ):
STS A DOF X/U = -0.337 [V]
STS A DOF Y/V = 0.17 [V]
STS A DOF Z/W = 0.584 [V]
STS B DOF X/U = 0.888 [V]
STS B DOF Y/V = 0.928 [V]
STS B DOF Z/W = 0.072 [V]
STS C DOF X/U = -1.081 [V]
STS C DOF Y/V = -0.328 [V]
STS C DOF Z/W = -0.434 [V]
STS EX DOF X/U = 0.55 [V]
STS EX DOF Y/V = -1.05 [V]
STS EX DOF Z/W = 0.414 [V]
 

This closes FAMIS task 4605.

Today I went to EY to investigate the issues with the PCALY OFS described in aLog 26229. The first thing I noticed upon approaching the PCAL TX module were a pair of cables (red and yellow) coiled underneath the TX module enclosure.  Upon first inspection, I didn't notice anything else egregious.  Everything was powered on and appeared to be functioning.  I then opened the TX module and verified that the PCAL beam was making it to the OFS PD.  As I was closing the TX enclosure, I noticed that a cable was exiting the TX module at a non-perpendicular angle.  I then noted that this particular cable was the OFS PD cable.  It practically fell into my hand as I went to check it.  I then plugged the cable back in and secured the fixing screws on the connector to the module.  For peace of mind, I then checked ALL cables on the TX module and chassis for security.  Satisfied I had fixed the problem, and unable to log into the workstation adjacent to the PCAL module, I returned to the control room.

While the signals on the PCALY MEDM appeared to be reasonable, Kissel suggested that I turn the 3 PCALY exc. lines back on the verify.  When I did so, I saw that the oscillation monitor railed.  Turning them on one at a time, I could get the first two on, but the third (1kHz, 15000 amp.) line caused a rail.  I gradually stepped up the amplitude of the 1kHz (3rd) line, and saw that at ~4000, it railed.  I began playing with the OFS offset, which was set to 0.56V, and saw that by increasing by a factor of ~3, I could turn on the 1kHz, 15000 amp. line without issue.  Trending the offset, I saw that it changed from 4V to 0.56V on Mar. 23.  I could not find an aLog referencing this change, so I have restored it to 4V. 

After finding an OPS shift aLog referencing Fil and Peter doing table access system work on Mar. 17, I asked Fil if they were doing similar access system work at PCALY on the 18th.  He told me that they had replaced the key switches on the PCAL setup that day.  He also told me that the pair of cables I had noticed coiled under the TX module were for the access system, but had been done further in the past.  Mystery 1: What could have happened to the OFS? SOLVED.  Mystery 2: Why does LIGO always have a loose cable? Unlikely to ever be solved.

J. Kissel, D. Barker
WP #5812

I'm continuing to work on filling out and debugging the recently installed SUSPOINT path (see LHO aLOGs 26363, 26321, 26320). 

I realized the part of that path which resides inside the OAF front-end model which projects the optic's Longitudinal displacement into the IFO Cavity Basis will need AI filtering for the corner station IPC channels (the ISI models send at 4096 Hz and the OAF model receives at 16384 Hz). Where there had previously only been test points and epics outputs to monitor the received channels, there are now full filter banks. Screens and details of filtering to come.

Also, while playing with the OAF model, Dave suggested we get rid of some more unused IPC connections. So, the "CONN" block -- some vestigial attempt at a monitoring system for the inter-process communication -- and its corresponding IPC senders (on of each flavor, Shared Memory SHMEM, Dolphin PCIe, Reflected Memory RFM) which had no receivers, have been removed. Attached is a screen shot of the block and senders we removed.

The latest version of the h1oaf model has been committed to the svn repo.

This required a frame-builder restart, but we've made no change to the DAQ channel list.

h1oaf, addition of filter modules and removal of connection monitor part with IPC channel. WP5812

Jeff, Jim, Dave:

h1oaf was modified to add more filter modules and remove the unused "connection monitor" system, which frees up an RFM channel per arm. After the DAQ restart, h1fw1 panic crashed with:

Kernel panic - not syncing: Fatal execption in interrupt

This time I power cycled h1fw1 (after lessons learnt Friday) and it has been running for 20mins so far.

HAM 8:   6 mA  @ IP and 2.6e-6 Torr at turbo
HAM 9:   8 mA and 6.0e-7 Torr at turbo
HAM 11:  10 mA+ (still with red light) and 2.1e-6 Torr at turbo
BSC4: 6.8e-6 Torr at turbo

   Cleanroom over HAM5 & HAM6 has been patched up and is powered up. A first cleaning was done this morning. Clean crew (give them a big thanks for the phenomenal job of maintaining cleanliness in the LVEA and at the Ends) gave the floor an extra scrub. Initial dust counts do not look too bad considering the activities this morning around HAM6.

   Staged two small cleanrooms on the south wall ahead of the doors coming off. Several work tables have also been staged.

   Will do a second cleaning tomorrow morning before the doors come off.     

Since HAM5 will be in the cleanroom and likely HAM5 will be bumped almost as much as HAM6, locked up HAM5 HEPI as well.

Position, relative to normally isolated:

-7um X, +15 Y, +31 Z, -10urad RX, -0.1 RY, +3 RZ.  The ISI remains isolated.  If the operator finds  either HAM5 or HAM6 tripped, maybe best to just put it in DAMPED.  The Chamber Manager has been paused since the HEPI can't isolate, so, you'll have to use the ISI Manager to change the guardian state.

Results are that three proof masses are out of range - I've emailed Hugh to make aware.

Averaging Mass Centering channels for 10 [sec] ...


There are 3 T240 proof masses out of range ( > 0.3 [V] )!
ETMX T240 2 DOF X/U = -0.387 [V]
ETMX T240 2 DOF Y/V = -0.399 [V]
ITMY T240 3 DOF Z/W = -0.303 [V]


All other proof masses are within range ( < 0.3 [V] ):
ETMX T240 1 DOF X/U = 0.041 [V]
ETMX T240 1 DOF Y/V = 0.063 [V]
ETMX T240 1 DOF Z/W = 0.083 [V]
ETMX T240 2 DOF Z/W = -0.251 [V]
ETMX T240 3 DOF X/U = 0.063 [V]
ETMX T240 3 DOF Y/V = -0.13 [V]
ETMX T240 3 DOF Z/W = 0.027 [V]
ETMY T240 1 DOF X/U = 0.011 [V]
ETMY T240 1 DOF Y/V = -0.069 [V]
ETMY T240 1 DOF Z/W = -0.02 [V]
ETMY T240 2 DOF X/U = -0.192 [V]
ETMY T240 2 DOF Y/V = 0.011 [V]
ETMY T240 2 DOF Z/W = 0.123 [V]
ETMY T240 3 DOF X/U = -0.028 [V]
ETMY T240 3 DOF Y/V = -0.026 [V]
ETMY T240 3 DOF Z/W = 0.071 [V]
ITMX T240 1 DOF X/U = -0.197 [V]
ITMX T240 1 DOF Y/V = 0.24 [V]
ITMX T240 1 DOF Z/W = 0.186 [V]
ITMX T240 2 DOF X/U = 0.201 [V]
ITMX T240 2 DOF Y/V = 0.244 [V]
ITMX T240 2 DOF Z/W = 0.227 [V]
ITMX T240 3 DOF X/U = -0.091 [V]
ITMX T240 3 DOF Y/V = 0.186 [V]
ITMX T240 3 DOF Z/W = 0.212 [V]
ITMY T240 1 DOF X/U = 0.165 [V]
ITMY T240 1 DOF Y/V = 0.027 [V]
ITMY T240 1 DOF Z/W = 0.095 [V]
ITMY T240 2 DOF X/U = 0.166 [V]
ITMY T240 2 DOF Y/V = 0.259 [V]
ITMY T240 2 DOF Z/W = 0.184 [V]
ITMY T240 3 DOF X/U = 0.037 [V]
ITMY T240 3 DOF Y/V = 0.194 [V]
BS T240 1 DOF X/U = 0.033 [V]
BS T240 1 DOF Y/V = 0.049 [V]
BS T240 1 DOF Z/W = 0.178 [V]
BS T240 2 DOF X/U = 0.12 [V]
BS T240 2 DOF Y/V = 0.196 [V]
BS T240 2 DOF Z/W = 0.205 [V]
BS T240 3 DOF X/U = 0.089 [V]
BS T240 3 DOF Y/V = 0.074 [V]
BS T240 3 DOF Z/W = -0.026 [V]


Assessment complete.

This closes FAMIS task 4367.
 

Completed locking around 0615.  Ready to tolerate rambunctious activities.

Position is pretty good wrt nominal: +19um X, +15 Y, +38 Z, +5urad RX, -3 RY, & +7 RZ. Plenty level for ISI work.

...at 7:20 am local time. Pressure reads 1.2 psig.

If you'd like to move the table, you need to do the following:

• Mark the position of the table on the floor using plumb bob or straight edge and sharpie.
• Disconnect the cables. (Cable connections are already documented.)
• Drop the lexan covers in the viewport cover slots and remove the duct materials connecting the viewports and the table.

PT243 - 1.17 x 10-9 torr 
PT244 - 1.57 x 10-9 torr 
PT210 - 1.57 x 10-9 torr 

I know, I know :)

Related alogs 26264. 26245

I did some follow-up tests today to understand the behavior of the DARM cavity pole. I put an offset in some ASC error points to see how they affect the DARM cavity pole without changing the CO2 settings.

I conlude that the SRC1 ASC loop is nominally locked on a non-optimal point (when PSL is 2 W) and it can easily and drastically changes the cavity pole. The highest cavity pole I could get today was 362 +/- a few Hz by manually optimizing the SRC alignment.

[The tests]

This time I did not change the TCS CO2 settings at all. In order to make a fair comparison against the past TCS measurements (26264, 26245), I let the PSL stay at 2 W. The interferometer was fully locked with the DC readout, and the ASC loops were all engaged. The TCS settings are as follows, TCSX = 350 mW, TCSY = 100 mW. I put an offset in the error point of each of some ASC loops at a time. I did so for SRC1, SRC2, CSOFT, DSOFT and PRC1. Additionally, I have moved around IM3 and SR3 which were not under control of ASC. All the tests are for the PIT degrees of freedom and I did not do for the YAWs. During the tests, I had an excitation line on the ETMX suspension at 331.9 Hz with a notch in the DARM loop in order to monitor the cavity pole. Before any of the tests, the DARM cavity pole was confirmed to be at 338 Hz by running a Pcal swept sine measurement.

The results are summarized below:

• SRC1, offset = from +400 to -300 cnts, cavity pole = from 350 Hz to 275 Hz
• SRC2 , offset = from +0.2 to -0.2 cnts, no change
• DSOFT, offset = from -0.03 to 0.03 cnts, no change in cavity pole, but a noticeable drop in the power recycling gain (41 --> 39).
• CSOFT, offset = from -0.03 to 0.03 cnts, no change in cavity pole, but a noticeable drop in the power recycling gain (41 --> 38-ish).
• PRC1, offset = from -0.1 to 0.1 cnts, no change in cavity pole, but a noticeable drop in the power recycling gain (41 --> 38-ish).
• IM2, some large offset, no change in cavity pole.
• SR3, offset = +/- 50 urad, no change in cavity pole or recycling gain.

The QPD loops -- namely CSOFT, DSOFT, PRC1 and SRC2 loops -- showed almost no impact on the cavity pole. The SOFTs and PRC1 tended to quickly degrade the power recycling gain rather than the cavity pole. I then further investigated SRC1 as written below.

[Optimizing SRC alignment]

I then focused on SRC1 which controlled SRM using AS36. I switched off the SRC1 servo and started manually aligning it in order to maximize the cavity pole. By touching PIT and YAW by roughly 10 urads for both, I was able to reach a cavity pole of 362 Hz. As I aligned it by hand, I saw POP90 decreasing and POP18 increasing as expected -- these indicate a better alignment of SRC. However, strangely AS90 dropped a little bit by a few %. I don't know why. At the same time, I saw the fluctuation of POP90 became smaller on the StrioTool in the middle screen on control room's wall.

In order to double check the measured cavity pole from the excitation line, I ran another Pcal swept sine measurement. I confirmed that the DARM cavity pole was indeed at 362 Hz. The attached is the measured DARM sensing function with the loop suppression taken out. The unit of the magnitude is in [cnts @ DARM IN1 / meters]. I used liso to fit the measurement as usual using a weighted least square method. 

By the way, in order to keep the cavity pole at its highest during the swept sine measurements, I servoed SRM to the manually adjusted operating point by running a hacky dither loop using awg, lockin demodulators and ezcaservos. I have used POP90 as a sensor signal for them. The two loops seemingly had ugf of about 0.1 Hz according to 1/e settling time. A screenshot of the dither loop setting is attached.

B. Weaver, H. Radkins, V. Sandberg

LHO WHAM6 Vent Plan for 2016 April 04 - 08

DCC Document: E1600092, “HAM6 - ISI Damper Install”

https://dcc.ligo.org/LIGO-E1600092

APPROVED work to be done in order of importance:

Install HAM ISI Dampers assemblies (Jim W., Nutsinee K.). 

Retune Tuned Mass Dampers (TMDs).

DCC Vent Documents referenced in this plan:

• E1600084, “Installation and Testing Procedure for HAM ISI Dampers”

a)   D1500469 Drawing documents for ham blade dampers

b)   D1600085  Drawing documents for GS13 dampers

c)   D1500200  Drawing documents for flexure dampers

d)   D0900703  Drawing documents for Tuned Mass Dampers (TMDs)

e)   E1100963  Retuning the TMDs

f)   T1500580 HAM ISI Damping Study - Mittleman

g)   G1500880  Damping Tests on Flexture Demo - Lantz

• E1100742 Payload layout update for HAM6
• D0901822 HAM6 Top Level Chamber Assembly
• E1201035 aLIGO Chamber Entry & Exit Procedures
• M1100039 Hanford Checklist - HAM Door Removal
• M1300464 Procedure for preparing aLIGO IFO for pumpdown

SCHEDULE

MON  April 4, 2016  (possibly prior if time allowed)

1)    Transition to LASER SAFE

2)    Turn cleanrooms on around HAM6

3)    Mark and move ISCT6 out of the way to facilitate door removal

4)    Clean area, door flange, and cleanrooms

5)    Stage supplies and equipment

a)     Contamination control kit

b)    B&K hammer setup and computer

c)     Various ISI damper assemblies

d)    ISI tool kit, TMD table setup

e)     ISI parts as per E1600084

f)     Septum viewport cover D1200448

6)    Confirm dust monitor is working

7)    Lock HEPI

8)    Confirm purge air is on at HAM6

9)    Vent HAM6

TUES  April 5th, 2015

10)     Remove ALL 3 CHAMBER DOORS – Review and follow M1100039 “ Hanford checklist – HAM Door Removal”

11)     Entry chamber checklist items: Pick up floor CC wafers.  Take particle counter measurements and record:

12) SEI Lock ISI 

13) Entry chamber checklist items: Pick up table top CC wafers. 

14)Install Septum Window Cover

15) Evaluate, mark and Move Beam Diverter ONLY IF ABSOLUTELY NEEDED for ISI work.  IF CABLES of Beam Diverter get removed, a test of the Beam Diverter function will need to be made before closeout.

16)     Start ISI damper install work. 

a) ISI Wall units need to be moved for this work. 

Note, DO NOT REMOVE ANY TABLE TOP OPTICS.  Confer with Keita before hand if this is needed.

b) Remove Tuned Mass Dampers (TMDs)

c) Install new spring damper assemblies

d) Measure new spring modes using the B&K System

e) Retune TMDs with new info

f) Reinstall TMDs

WED  April 6th, 2016

17) Continue ISI damper install work.

18) Take particle measurements and record:

THUR  April 7th, 2016

19)  Finish ISI damper install work

20)  Check Beam Diverter functionality

21)  Quick check of ISI Balance and clean TF

22)  Remove Septum Window Cover

23)  Chamber closeout – perform applicable exit checklist tasks E1201035.

24)  Take particle count measurements and record:

25)  Replace 1 HAM6 door if possible

FRI,  April 8th, 2016

26)  Replace remaining HAM6 Doors

27)  Begin pump down

              28)  Reset ISCT6