Morning Meeting Minutes

SEI - All good. Progress was made with the shutter last week; different filter, too high gain settings (see alog29149).

SUS - All good.

CDS - Running.

    Pulling chasis at ends for Beckhoff tomorrow.

PSL - All good.

Vac - HAM6 still coming down slowly.

    Tomorrow terminate the cables for the ion pumps. Software needs an update. RGA baking.

Facilities - HVAC system contractors here.

    Tomorrow moving items around in LVEA.

Interview and PNNL tour tomorrow in LVEA

Please finish maintenance by NOON tomorrow.

locking today

Sheila Terra Evan

This afternoon we made some progress on things that were making locking difficult, and only a little progress on getting to low noise.  

• DRMI asc engaging changed a little (the input for the MICH ASC filters is turned on earlier) so that the guardian can now be allowed to run without intervention and turns on MICH, PRC2, INP1 loops.  
• Added a state to ISC_LOCK (ADJUST_OFFSETS) that adjusts the POP and MICH offsets to that is currently used after powering up to 50 Watts.  We tried to move the offsets before powering up, but found that at 2 Watts these offsets reduce the recycling gain. 
• Fixed a problem with the way the ISS 3rd loop was turned on that meant guardian did not recognize some locklosses.  (This caused unforseen problems and cost us some time, but is fixed now.)  The third loop is now handled by the IMC guardian. 
• ITMs are using offloaded control now, for some reason the ITMs and ETMs had been different.  This is accepted in SDF. 
• We rearranged the order of some guardian states, and took PREPARE_ISS out of the coil drivers state.  (We need to do low noise ASC before we swtich coil drivers if we are adding the quad switching to coil drivers.)
• We found that LOWNOISE_ASC did not work because for some reason the gain at high frequency of the 40 Watt compensation in CHARD P was -10 dB, while it should have been 0dB.  This seems like it must have changed since last time we used this state, the rest of the 40 Watt compensation filters were fine, with 0 dB at high frequency.  
• With this fixed we could do the first several steps of lownoise ASC, but broke the lock at the end.  I am not sure why
• PI stuff has been good tonight, we are going to leave the IFO locked at 50 Watts in a high noise state.  

Checking recent timing system interventions with folded magnetometer data

Summary: The interventions in late July and early August to disable blinking LEDs and isolate timing system power supplies
have made some difference in the periodicities that emerge when folding magnetometer data from the end stations, with the largest
difference seen with the initial firmware updates done in late July. 

Details:
Weigang Liu has been cumulatively applying his folding algorithm to magnetometer data from January through
early August, including periods before, during and after recent attempts to mitigate leakage of periodic
(1 Hz and 0.5 Hz) transients seen in magnetometer channels into DARM. [Recent clogging of the Caltech 
cluster nodes with sufficient memory has delayed the automatic production of these plots, so Weigang did
a bunch of jobs manually on head nodes for this report.]

Summary of recent interventions:

July 19 - Upgrade of timing slave card firmware to disable alternating on/off blinking of LEDs with 2-second periodicity (on 1 second, off 1 second), suspected to lead to alternative positive / negative current transients that affect DARM.
August 2 - Upgrade of EX timing fanout card firmware for same reason
August 5 - Isolation of timing card power supplies 
August 9 - Upgrade of EY timing fanout card firmware 
August 16 - Additional timing card firmware upgrades in LVEA, EX, EY


The following table includes links to summary pages for most of the days to date of 2016 (some condor jobs still pending)
for six end-station magnetometer channels, along with comments on changes visible from July 16 to July 21, then to August 6, then to August 18,
along with figure attachment numbers showing the folded data plots for those days.


Channel / link to 2016 web pages
Figure attachments
July 16 to July 21 changes
July 21 to August 6 changes
August 6 to August 18 changes
H1:PEM−EX_MAG_EBAY_SUSRACK_X
1-4
Improved
Higher peaks
Similar
H1:PEM−EX_MAG_EBAY_SUSRACK_Y
5-8
Improved
Higher peaks
1-Hz structure different (not better)
H1:PEM−EX_MAG_EBAY_SUSRACK_Z
9-12
1-Hz structure worse
Similar
1-Hz structure reduced
H1:PEM−EY_MAG_EBAY_SUSRACK_X
13-16
Improved
Similar
Similar
H1:PEM−EY_MAG_EBAY_SUSRACK_Y
17-20
Worse
Even worse
Similar
H1:PEM−EY_MAG_EBAY_SUSRACK_Z
21-24
2-Hz structure smaller, 1-Hz structure worse
Similar
Improved

PI work

PI damping working, though all gains required a sign flip. Successfully damped ETMX mode while ETMX ESD was in HV mode thanks to recent mod.

Modes 17 (ETMX), 25, 26, 27 (all ETMY) rang up. All four have been in guardian and were damped tonight with a sign flip of the gains. I was able to check some phase optimizing but locks were too short for much investigation. I've saved these changes to the guardian and they auto damped the next lock successfully. 

back to 50 Watts

• Terra aligned the POP GigE camera. 
• We had no problems with DHARD tonight, it is back at the nominal gains of 30 for pitch and 40 for yaw durring power up (this is in guardian). 
• We can improve the recycling gain to about 30 (according to POP/IM4) at 50 watts using the POP A offsets that worked before the vent:  0.5 in POP_A_PIT and 0.4 in POP A yaw.  We found that putting these offsets in moved the beamsplitter and decreased the sideband build ups as we saw before the vent.  By adding an offset of 1300 to ASC_MICH_P and 500 to ASC-MICH_Y we were able to recover the sideband build ups. 
• We lost lock due to the CSOFT instability when the coil drivers state turned off the ISS 3rd loop to prepare for turning on the second loop. The easist way around this may be to use the new electronics. 
• DRMI ASC has been difficult, and I have had to hand adjust alignments and turn on loops by hand every lock. The alignment is bad after every lockloss, which could be due to some heating.  I commented out PRC1, SRC1, and SRC2 from the guardian, this worked once after hand tweaking in PRMI.

Ops Evening Shift Summary

Title:  08/19/2016, Evening Shift 23:00 – 07:00 (16:00 – 00:00) All times in UTC (PT)
State of H1: Relocking after PSL back in operation.   
Commissioning: 
Outgoing Operator:  Ed
 
Activity Log: All Times in UTC (PT)

23:00 (16:00) Start of shift
23:12 (16:12) Filiberto – Powered on ITM HV power supply
00:11 (17:11) Kyle – Into LVEA to adjust RGA in Vertex
00:19 (17:19) Kyle – Out of the LVEA
04:58 (21:58) Sheila & Terra – Going to IOTC1 to work on camera alignment
05:20 (22:20) Sheila & Terra – Out of the LVEA


Title: 0819/2016, Evening Shift 23:00 – 07:00 (16:00 – 07:00) All times in UTC (PT)
Support:   Sheila, Terra, Evan
Incoming Operator: N/A

Shift Detail Summary:  Commissioning work continuing.

Framewriter stability investigations

This week we were put h1fw0 back into an unstable configuration by asking it to write out all the frames (full, science, strend, mtrend).

We were able to extract some useful information from the crashes.  The main point is that for some reason IO starts to become unstable and the raw frames end up taking too long to write.  This eats up all the internal buffers, and the system crashes.

I did some tweaking of nfs settings which brought the frame writing threads to have more stable write times.  Even with that a hiccup was observed which allowed the science and full frame to get a cycle out of sync, with the full frame writer being unable to catch up.

Today after looking at the code I have a new build of the framewriter running on h1fw2. This splits the framewriting thread into two parts, to allow parallel execution and allow the full frame writing threads the chance to catch up if they fall behind.  So far h1fw2 is stable.  We will test it on h1fw0 next week.

CP3 overfill

4pm local

45 sec. to overfill CP3 with 1/2 turn open on LLCV bypass valve

LLCV is currently as 20% open

ITM ESD High Voltage Power Supplies

The ITM ESD HV power supplies were powered on this afternoon ~4:15 PM. I believe the units have been off since the HAM6 vent.

Shift Summary - Day

• mostly opportunistic maintenance
• LASER back on. revovery/alignment process begun

Opitcal Lever 7 Day Trends

This was done using JIm W's new script! (More on that another time)

All OpLevs look good, except ITMX Pit. Seems to be slowly drifting off, current value at 13.

 

FAMIS#4689

HAM 6 turbo spun down

Kyle, Chandra

Isolated turbo on top of HAM 6 and spun it down, turned off scroll pump, decoupled foreline piping. Left turbo energized until bearing if fully de-levitated. 

NOTE: climbed on top of HAM 6 to do this work. 

Will de-energize turbo by Monday.

I had intended to shut down the pump cart pumping the Vertex RGA (also de-energize the HAM6 turbo controller) on Saturday morning, decouple it and then combine (valve-in) the RGA to the Vertex volume.  However, I forgot to get a Work Permit approved for this prior to people exiting for the weekend.  I confirmed with Keita, Sheila and Terra that their activities would not be hindered by leaving this noise source running over the weekend so, I will do this on Monday morning.  

PSL Recovered from Water Leak

P. King, J. Oberling

Short Version:  The PSL is now up and running following the HPO water leak (first reported here, repairs reported here).

Long Version:  This morning, after giving the HPO ~48 hours to completely dry, we inspected the HPO optical surfaces.  The only thing found was some water spots on the head 1 4f lens (this was drag wiped clean); all other optical surfaces look good.  We then slowly brought up each head individually to ensure no contamination was causing the optical surfaces to glow; all good here as well.  The HPO was then successfully powered up an allowed to warm up for several minutes.  The front end came on without issue and the injection locking locked immediately.  After allowing the system to warm up for ~1 hour, I attempted to lock the PSL subsystems (PMC, FSS, ISS).  The PMC did not want to lock; according to Peter this was likely due to a slight horizontal misalignment (this is seen in a trend of the QPD that lives in the ISS box.  I unfortunately don't have a copy of it).  I returned to the enclosure and tweaked the beam alignment into the PMC and it locked without issue.  I then tweaked the PMC alignment further to maximize the power throughput.  PMC now has a visibility of ~80% with ~122W transmitted (with ISS on).  The FSS and ISS both locked without issue.  The PSL is now operational and fully recovered from the water leak.

Information about the mis-alignment was obtained from the reflected spot CCD image,
not the ISS QPD.

TCS Y arm laser

[Alastair, Jason, Ben, Vern, Dave]

Thanks to everyone for their help getting this work done.  The Y-arm TCS laser is now running full power, and the table is fully aligned.  The in-loop photodiode is also now working again.  Details below.

Tuesday we discovered the laser on the table (SN 20306-20419D) had previously been paired with the driver that went with the spare laser ( 20816D-20510).  The laser had been outputing 40W at the time.  When the Hanford team had swapped in the 'spare' driver they actually were putting in the one that matched up with the laser (SN 20419D-20306) and the power went down to 16W.  First thing we did on Tuesday was to add irises to the table to define the optical axis after the laser.  We added blocks to the table to define laser position We then swapped in the spare laser (20510-20816D) and aligned to the blocking, and we found the power outputs were ~14W with its mating driver, and ~40W with the driver SN20419D-20306.

Checks on as much of the electronics as we could test showed no problems (RF distribution system, controller voltages, power etc).

Wednesday we decided the fastest way to diagnose the drivers was to swap them in to the working X arm table.  Driver SN 20419D-20306 gave a power output of 58W.  Driver  20816D-20510 gave 42W.  Swapping back to the original X arm laser (SN 20706-21015D) and driver combo gave 60W so at this point we left the X-table in its previous working condition.  Conclusion was that driver SN 20816D-20510 has now given output of ~40W on three separate lasers and appears to have some issue.

Moving back to the Y-table, two issues were noticed.  Firstly there was very minor discoloration on one pin of the power cable for the laser.  Ben also said that the pin looked badly seated and did some corrective work on this (we should check with him if he thinks this needs further work).  Secondly the power meter height was adjusted to make sure the aligment to the laser gave the largest apeture possible - this could with a little misalignment oclude part of the beam.

We repeated measurement of spare laser SN20510-20816D with driver 20419D-20306 getting 49W output.  We then completed the cycle of tests by putting in laser 20306-20419D with its matching driver 20419D-20306 and getting 58.6W output.  It's not clear what fixed the problems - the power cable seems a likely candidate but behavior of the laser still doesn't seem totally consistent with this (if one half of the driver was getting no current we would expect ~25W output).  We also might want to test driver  SN 20816D-20510 to check whether the power connector (which looked okay when visibly inspected) might be a cause for its performance drop.

After the laser swaps the final laser configuration was aligned to the blocking on the table and then to the optical axis with some minor tweaking of the actuators on the first mirror on the table.  The laser was aligned through the whole table.  At the mask we aligned by maximizing transmitted power, then using the FLIR camera on remote desktop (yes this works now - thanks Dave Barker) we tweaked the alignment to make the beam symmetrical after the mask.  We then aligned to the irises at the output of the table which define the optical axis into the vacuum system.  We changed the alignment onto the power meter that gives the power output to the CP because the head was too close to a focus.  We checked the calibration of the power output to the CP and this was confirmed accurate.  Finally we aligned to the two photodiodes on the table.  Inloop was not giving an output but we swapped cables with outofloop and were able to get a signal to align to.

The problems with the in-loop photodiode were traced to being a bad ADC board which has now been swapped for the spare (thanks Ben & Jason for tracking this down).

The Y-table will have the output to the vacuum system unblocked so the system is ready to go.  The laser will be left keyed off, with the rotation stage set to minimum power.  When the system is needed it just needs keyed on at the rack in the LVEA, and then power increased at the rotation stage.

some ASC work

Terra, Sheila

Tonight we had trouble engaging the ASC again.

• We still have trouble turning up the gain in DHARD, and didn't get a chance to look at this tonight. We did try reverting the ETMX notches but that doesn't solve the problem. 
• We also had trouble with our MICH error point being wrong, which might have been related to TCS being off durring maintence.  Now that TCS has been on for several hours the MICH loop seems to be working OK. 
• We had to restore OMC QPD offsets that weren't in SDF before today's boots.  We are now back in DC readout. 
• Once we reached DC readout we manually tried the CARM gain redistribution that we had commented out of the ANALOG_CARM state yesterday, and we did not see glitches reappear in the MCL drive.  We left this uncommented in the guardian, so we can try this in the morning.
• Jenne reset the soft offsets for our new alignment, and we also got rid of the POP A yaw offset.

Losing optical gain in POP X

We rang up what we think is a PR3 bounce mode when engaging the ASC the same way as last night.  We found that we could avoid ringing this mode up by keeping the PRC2 gain low (digital gains of -500).  Right before the OMC damage/vent, the POP X path was reworked and the optical gain seemed suspiciously low. 

Tonight we found that the optical gain has decreased even more.  Terra changed the demod phase by dithering PR3 pit (500 counts to M3) and rotated the phase positive 65 degrees, (Q1, Q2, Q3, Q4 from 55, 53, 54, 51 to 120, 118, 119, 116 ) to maximize the signal in I (minimize the Q signal).  The 2 attached figures show Terra's before and after OLG measurements (excitation gain of 50), both with Jenne's gain of -5000, showing a 10dB increase in optical gain which is about what we expected based on the dither amplitude change. 

After optimizing the phase, we did not see the 28 Hz mode get rung up, but this seems to come and go because we also didn't see it yesterday.  We quickly tried moving L2 on the POP X path, while watching the amplitude of the PR3 dither line in the POP X signal.  We moved the lens about 4 inches closer to POP X and about 3 inches further away, and didn't find any location that had more signal for PR3 so we replaced it as we found it. 

We are going to leave the IFO locked in DC readout 2 Watts with the request set to down so that it will not try to relock. The noise is bad as expected. 

PI dark region

I have been taking spectra from the SR785 (WP6005) whenever I get a chance over the last week to see if there is any evidence of three mode interactions in the 60kHz to 70kHz region that we will not be sensitive to with the aliased OMC DCPD HF channels that we normally analyze.
There is a consistent peak at 62935Hz, this peak is present with no optical power in the arm cavities.
There are several other more transient peaks, one of the times several had large amplitudes is shown in the first figure.
The largest peak is at 63776Hz  The maximum amplitude seen was 5E-6  This is about the same as the 18040Hz mode when it is 2 orders of magnitude above thermal noise and 2 orders of magnitude under unlocking the cavity.
The second largest is at 70160Hz and the third largest at 62336.

There is no evidence of peaks in DARM at this time at the expected aliased frequencies 1760Hz,  3200Hz or 4624Hz and the peaks that appear in the HF channels that do not appear in the normal DCPD channels do not coincide in frequency, see the second image.

J. Kissel, T. Hardwick

We've taken the liberty of rifling through Carl's home directory in hopes to find the raw data from this entry to re-plot for clarity. We found it!

The newly attached plot now highlights the PI modes that Carl mentions in his aLOG, and also shows the anticipated ADC noise. Thus, any modes below 6.3e-6 [V/rtHz] should not be resolved by the ADC, and therefore will show up aliased into digitized signals in the detection band. 

Terra notes that the mode Carl mentions at 70160 Hz is the largest of several peaks at 69.84, 69.95, and 70.03 kHz (not highlighted), which is likely a mode cluster.

Other details:
The raw data lives here (determined by Terra knowing that Carl keep his GPIB data in his home folder, then lining up the data on the figure with the filename): 
/ligo/home/carl.blair/gpib/netgpibdata/dataSPSR785_24-07-2016_212424.txt

This data (as described in the referenced work permit 6005), is the raw analog output of the TMSY's red QPD's whitening chassis.

This data also happens to cover the frequency region surrounding the 65536 [Hz] native sampling frequency of the General Standards ADC, and the corresponding notch in all Anit-Aliasing (AA) chassis. One can see, delightfully, that there is very little noise or lines in this frequency band on this channel that might also otherwise be aliased down to low frequency. 

We should perform a similar spectral analysis of the OMC DCPD whitening chassis output voltage to check if their AA chassis is also sufficiently notched so as to not contribute noise in to the DARM sensitivity.

Low-noise DARM loop retuning

I removed the 300 Hz and 600 Hz stopband filters in DARM, along with the 950 Hz low-pass filter.

I increased the gain from 840 ct/ct to 1400 ct/ct, giving a UGF of 55 Hz. This seems to have improved the gain peaking situation around 10 Hz (see attachment).

The new settings have been added to the guardian (in the EY transition state), but have not been tested. The calibration has not been updated.

Tagging CAL Group. Evan Goetz has also been working on a better PUM roll-off. He'll be installing those improvements soon as well, and a full loop design comparison.

Another CO2 differential lensing test

This is a quick summary of today's TCS joy. I ran another differential lensing test today. I went to the other side of the differential lensing (CO2X goes higher power).

The highest cavity pole was 352 Hz in this test.

• CO2 X 500 mW --> 700 mW --> 500 mW
• CO2 Y 230 mW --> 80 mW --> 230 mW

This time, I also took many measurements of the intensity and frequency noise couplings periodically throughout the test using Evan's automated measurement script (20470). I will analyze and post them later. The second attachment is trend of some relevant channels.