PR3 - 2 rounds of noise hunting

The spectra taken since the M2 stage AOSEM bracket swap last Friday (15th) show slightly anomolous peaks (not glaringly wrong, but not great).  This morning we attempted to remedy the mis-centering of the M1 UL AOSEM which we thought might be brushing the magnet.  After deeming it ok, Arnaud's spectra revealed it still to be bad.  This time I went in and played with both the UL and LL attempting to center the AOEM with it buried over the magnet blocking all of the light.  This old standby technique was not very helpful though because as you draw the AOSEM back out to 50% open light, the AOSEM walks all over in the bracket nulling the alignment.  The stackup of brackets at this stage are not very nice (putting it nicely).

The picture below shows how all 4 AOSEM brackets are crooked relative to the structure and the suspended mass with the "modified" brackets.  We needed to make new brackets here.  Too late.  (Although I have Tyler making a fresh set for SR3, now that I am aware of the problem.)

I also found that one of the 4 top mass EQ stops was brushing the top mass.  This could have been the culprit the whole time, but nevertheless, the M2 stage brackets don't look right.

PRM unplugged and ready for transport to HAM2

Yesterday, Travis did this.  PR3 is the first one we need, however but it's good to get this work done.

Ops review

- 8:15 meeting Richard mention alarm ITMY OSEM3 was on

- 10:00 Filiberto shut down ITMY electronics - turned on at 12:00, followed by oscillation on OSEM5 and OSEM6, solved by Pele and Mark

- 11:30 Patrick activated DUST monitor 9

Yesterday, I powered down the ITMY coil drivers. I disconnected and reconnected field cables at the SAT units inside SUS H1-R6. This was done to help finish dressing cabling inside the rack. When units were reconnected and powered up, we saw a high frequency oscillation as described by Pablo. We were able to remove the oscillation by power cycling the AA units.

Installation of the ALS periscope mirrors done

 Both the upper and lower mirrors of the ALS-PSL periscope were installed this morning.
Also I have spent some times to align the entire ALS path on the table so that the beam can nicely climb up the periscope and hit the center of the penetration hole and duct on the PSL enclosure wall (see attached picture). This work required the WP #3723 and the metal cap of the penetration hole was put back on afterward. The ALS beam is ready to enter the HAM1 chamber (although a light pipe will be required).

/* some notes on the beam power */
before ALS-Faraday = 125.8 mW
after ALS-Faraday =  123.9 mW

started dust monitor 9 in the LVEA

It is in the clean room in front of the west door of HAM1.

HEPI Plumbing Leak Testing Update

Since Wednesday when the welder completed the gross leak fix, the system had been losing about 1psi per day.  On Saturday all the valves to the distribution manifolds (at Chambers) were closed.  The pressure loss trend continued and yesterday a small leak was found and stopped on a Swagelok fitting under BSC1 where a 1/4" valve provides bleeding at a high point.  This morning the pressure was found to be holding so the main line valves have again been opened.  No pressure drop was observed so I am optimistic things are now leak free.  I may vent a couple small sections to install pressure transducers.  Otherwise will monitor the pressure for another day or so before calling it good.

plots of dust counts

Attached are plots of dust counts > .3 microns and > .5 microns in particles per cubic foot requested from 5 PM Feb. 18 to 5 PM Feb 19. Also attached are plots of the modes to show when they were running/acquiring data. I'm not sure why dust monitor 4 in the LVEA stopped. I have restarted it.

Data was taken from h1nds1.
2880 seconds worth of data was unavailable on this server
1440.0 minutes of trend displayed

CDS Maintenance Summary

lhocds. changed nat routing for ports 22 and 2222 such that SSH now routes to the 2fa server.

h1seih16. IO chassis power supply swap out and restart of front end. Dolphin problems meant we had to restart almost all MSR models which have Dolphin IPC.

h1dc0. went down a few times this morning in order to clone its boot disk in order to build h1dc1.

worked with PSL and HAM ISI groups to revert some recent SVN file changes.

Changed the NAT configuration of marble/h1dmt0 to route to the new ligo.org auth login server as part of its install process

Performed OS upgrades of some CDS servers.

Inspection in HAM2:

Jodi and I inspected HAM2 withness plates and surfaces, and found a lot of articulate.  Wafers also have visible finger prints, that I put there installing them - good reason to use our nifty wafer tweezers.  Particulate found on all wafers.  Examples include but are not limited to white fibers, black flecks, white flecks, metal flecks, bright red stuff, and a bit of First Contact.

- Jodi, Cheryl

Observations of witness plates and other in-chamber surfaces goes as follows:

Every surface we looked at had particulate, including table top, optic structures, etc.  Optics, both small fixed 2" and the larger 4" IM2 and IM4, show particulate.

Witness Plates:

- Worst contamination: 
One 4" witness plate on the HAM2 table top:
Exposed during IO installation, pump down and vent.  
Significant particulate, and my gloved hand print.

- Competing for the next worst contamination:
Two 4" witness plates in the beam tube, North and South of HAM2:
Exposed during pump down and vent.  
Large particulate easily seen from about 1.5m away.

Two 4" witness plates in the bottom of HAM2:
Exposed during pump down and vent.  
Large particulate easily seen from about 1.5m away.

- The winners, showing the least contamination:
4" witness plates in the beam tube, West side of HAM2 on ISI level-0, positioned North, Center, and South:
Exposed during pump down and vent.  
Small particulate easily seen by eye.

- The three 1 optics had some particulate but were very hard to evaluate in-chamber, so hard to say how much contamination is on their surfaces until we can pick them up.  There was a piece of First Contact, about 1mm square, on one of the 3 optics - it was missed by at least two sets of eyes before pump down.  The up-side is that this does show that FC stayed put on an optic during pump down and venting.

Current State of Witness Plates in HAM2:
We did not have containers to remove wafers or 1" optics, so new wafers were installed along side the old wafers, (in every position, the new wafer is installed in the counter-clockwise direction from the old wafer).  Two new wafers replaced the old table top wafer, and the old wafer was moved across the table, to prevent it from contaminating the new wafers.

Apollo crew

Moved cleanrooms in south bay per request from Betsy with approval from Jodi. Started ICC at BSC 10, documented chamber, pictures, wraped support tubes, covered RGA per instruction from Kyle. Ran compressor to blow out cobwebs and ready to start brushing tomorrow. John and I glued measurement spheres for reference before and after removal of coupon on sample beamtube and started setting up for coupon cut with plasma cutter.

HAM2 dummy payload removed

HughR, JimW, some Apollo

This afternoon, after Jodi and Cheryl did their in-chamber cleanliness assessment, we removed the dummy payload from the HAM2 optical table (6x 50lb masses and 3 10kg masses). No other components were touched, so there maybe other components to be removed from the table before PR's are installed.

Phase 1b M1 Transfer Functions for I1-MC2

   Attached are the plots for the M1 level transfer functions for MC2. This is the first of the India HSTS suspensions to be tested. The plots look good. While Stuart Aston and Jeff Kissel are reviewing these results, we will install the AOSEMs and prep MC2 for the power spectra tests.      

PR3- M2 AOSEM Brackets swapped

Late last week, Deepak and I precariously swapped the problematic and AOSEM brackets described in my previous alog:

https://alog.ligo-wa.caltech.edu/aLOG/index.php?callRep=5499

 

I use the word precarious because the operation meant that tools, small fasteners, and hands were wedged inside of the suspension above the optic and extremely close to fragile wires in order to replace the 4 brackets.  This did not make me happy.  See some pictures below, but the collection is also posted  ResourceSpace: https://ligoimages.mit.edu/?r=23901

HAM3-ISI - Level 3 Controllers

HAM3-ISI level 3 controllers were designed on Jan 16th 2013. Controllers are shown in the first .pdf attahcement of this post, and saved in the SVN under: /seismic/HAM-ISI/H1/IMC_Test/Isolation_Filters/HAM3/

Those controllers were designed on in-air measurements. In-air VS In-Vacuum comparisons show that the major resonances we account for during ISO loops design are not affected by switching from in-air to in-vacuum.

cdsfs0 and h1seih16

cdsfs0 was reset. I verified from the control room that I could recover this system "remotely" via the administration port. If it fails again before Tue I'll try to remotely recover it, but for now it appears to be a Saturday problem.

h1seih16 When I got to the control room at 15:30 I noticed that h1seih16 had been frozen from 13:15. I took it out of the Dolhin fabric and tried restarting the models, but no I/O cards are detected. I took a quick look at the IO Chassis and found it without power (front panel switch is ON, 24V power strip has +24V LED ON). It looks like  a power supply issue so I'm leaving this till Tuesday. I'm running the models to "green up" the EDCU, but no useful data is coming from HEPI HAM1.

/ligo file system is in read-only mode

For the second saturday in a row the /ligo file system at LHO has issued a scsi error and switched to read-only mode. I'll drive to the site later this afternoon to reboot it. We will work on replacing the scsi controller card next week to see if we can fix this problem.

The error occurred at 08:06 today, at at 00:05 last sat.

Friday Summary

• See the entry by Kyle and Gerardo about their MX vacuum gauge changeout
• The HAM 2 east door appears to be off
• Rick and Kyohei operated the 10W laser in the LSB lab
• Three alarms from dust monitor 4 occurred mid-morning while Cris was cleaning the work platform and the floor in the BS test stand clean room
• Betsy:  Changeout of PR3 SUS brackets
• Sheila:  Worked on picomotors at EY
• Justin:  Heavy lifting at clean and bake
• Keita, Kyohei, Gregorio:  Inspected the OMC in the H2 PSL enclosure
• The CDS channels listed in the morning entry remain yellow
• Work permits signed by ops today:  3717 (HAM 2 cleanings), 3718 (10W laser), 3719 (MX vacuum gauge)

PR3 Phase 2b Power Spectra

Attached phase 2b power spectra for PR3.
The two first pdfs show a comparison of the power spectra between L1-PR3 (June 2012),X1-PR3 (June 2012) and H1-PR3 (Feb 2013) respectively damping off and damping on.
The three others show the effect of damping for the top, middle and lower masses of PR3

New power spectra will be taken tomorrow since Betsy has to change some of the OSEMs.

IMC pole measurement

[Rodica, Kiwamu, Dick, Michael R., Keita, Paul]

Last night and today we finally managed to get what looked like a good measurement of the IMC pole response. Here is a brief description of the measurement setup:

Swept sine signal applied directly from the SRS785 to the AOM driver box inside the PSL. Frequency range was 1kHz to 100kHz, signal amplitude was 400mV pkpk. 1000 intergration cycles, and 101.56ms integration time. Measurement was a transfer function from the DCPD on the PSL installed recently (PDA55) to the DCPD on the IOT2L table (DET100A). ~200mW injected to modecleaner.

The PDA55 on the PSL table didn't give us an observable signal from the amplitude modulation previously when we tried on Wednesday. Rodica checked the Thorlabs recommendation for best linear performance, which states that the maximum intensity should be less than 10mW/cm^2. Even with a very low beam power we may have been exceeding this value due to the very small beam size. The PD was therefore moved to have a larger incident beam size.

We were struggling to get a decent signal on the SRS785 until Kiwamu suggested reducing the light power reaching the PDs to less than 1V. Once we brought the power down to less than 600mV, we were able to see a decent signals on the SRS785 and began taking TFs. 

The first attached transfer function is directly from the PSL PD to the IOT2L PD. In the event that the response of both PDs is linear, this should just give the cavity response. However, we noticed that the phase dropped below -90deg on the TF, indicating the presence of another pole - likely that of one of the PDs. We therefore took a TF from the PSL PD to the IOT2L PD, with the IOT2L PD repositioned in the IMC REFL path and the cavity misaligned (as Giacomo did previously). This TF is the second attached plot, and shows the pole of the IOT2L PD. Finally, we then divided the first transfer function by the second to eliminate the different PD response, leaving us just with the cavity response. This transfer function, along with a fit, is shown in the third attached plot.

For now, I just fitted the phase of the pole measurement, which gave the result 8812.36 Hz for the cavity pole. I'll try a complex data fitting routine soon and post the result.

IMC noise

Attached is a plot of the calibrated IMC control signals for the following relevant control loop settings:

- Common Mode Board: common gain = 20 db, compensation and 1st common boost on, fast gain = -2 db.

- MC2_M3_LOCK_L filters: gain -1000, FM5 (150:4) and FM8 (CLP100) enabled, limt to 400k.

- MC2_M2_LOCK_L filters: gain = 0.03, FM1 (0.01:0.1), FM2 (0.03:1), FM3 (Stab8:2), FM4 (300:1) and FM10 (ELF80) enabled, limit to 300k.

 

The signals have been calibrated following L1 example. Details on the calibration follow (both for clarity and to check that I correctly interpreted what they has been done at L1).

---- IMC_F ----

- The fast path control signal is directly acquired from the Common Mode Board and becomes the input to the H1IMC-F filter bank (H1:IMC_F_INMON)

- the filter bank contains the following (enabled) filters:

   - "cts2V" that converts ADC counts in volts (0.000610016 V/ct)

   - "InvGenFilt" that compensates for the withening filter at the output of the Common Mode Board (double pole at 10 Hz, double zero at 100 Hz, DC gain = 0.5)

   - "VCO" that accounts for the VCO DC gain (365714 Hz/V, obtained from the test report of unit D0900605-S1200558 and multiplied by 2 to account for the AOM double pass) and filter (pole at 1.6 Hz, zero at 40 Hz)

   - "FtoL" (I added this at H1) that converts the frequency variations dF into equivalent modecleaner round-trip variations dL using dL = dF * L * lambda / c, where L is the length of the IMC (16.47 m nominal), lambda = 1064e-9 m, c=3*10^8 m/s.

 

---- IMC_X ----

- the output of the MC2_[M3/M2]_LOCK_L filters are input in the IMC-X_[M2/M3] filters bank, respectively

- the MC3 filter bank contains the following enabled filters:

   - "dc_cal" that converts the length actuation into mass displacement at DC

   - "sus_d" that accounts for the TF from force on M3 to displacement of M3 (rescaled for 0 dB DC gain because of the existence of "dc_cal"). Note that this TF has been calculated for L1 in the case of velocity damping; although we are still using velocity damping here at H1, it need to be verified that we are using the same setting that L1 was using when the TF was calculated.

   - "white", a whitening filter (two 0.2 Hz poles and two 1000 Hz zeros) used to get rid of digitization noise. It need to be tken into account when analyzing data.

- the MC2 filter bank contains similar filters, except that "sus_d" is replaced by the combination of "sus_d1" an "sus_d2", that account for the TF from force on M2 to displacement of M3.

- the outputs of both filter banks are summed to estimate the actual M3 motion.