Set the local audible alarm on dust monitor #1 at End-Y. The 0.3 alarm is set for 18 particles (@500 MEDM counts) and the 0.5 alarm is set for 10 particles (@300 MEDM counts). These values may need adjusting as more data points are collected.    

Green team:

• Stabilize the red/green difference using a slow feedback path.
• Hand-off to red.
• Noise measurement between red and green locked on red.
• Make a mode scan of the red resonances.
• ETM drive diagonalization for length and angle..
• ITM drive diagonalization for angle.
• Centroid fit for ITMX camera..

Red team:

• Commissioning of the initial dither alignment system.
• Fix: BS feedback triggering an ISI trip.
• Center the red QPDs in EX.
• Investigate the robustness of the 3f lock in presence of an arm cavity
• Start commissioning the alignment system.
• REFL_A calibration.
• Optimize the thermal compensation of ITMY.
• Investigate the REFLAIR45 whitening filter issue.
• PRC length measurement.

Blue team (ALS WFS):

• Stability investigation.
• Re-measure sensing matrix.
• Beam quality investigation.
• Diagonalization of dither alignment feedback.

Blue team (ISCTEY, delayed):

• Prepare second set of WFS Complete the feedthrough panels.
• Install the on table cabling.
• Prepare for move to the end station.
• Check out ALS electronics in EY.
• Add WFS.

TMS:

• Ground loop investigation.
• Beam alignment in final position.

SEI/SUS team:

• Install optical lever damping for vertical and roll modes.
• Improve stability under high performance for ETMX.
• Fix: TwinCAT reboot trps HAM ISI.

Kyle will be craning the portable RGA over the Y-arm in the vicinity of the elevated slab and test stand areas. Work should be complete by noon. See WP 4455.

Summary: Acoustic coupling at HAM6 (dark port) is likely to be a borderline noise source for aLIGO, near the expected noise floor in the several hundred Hz region, as it was at the end of eLIGO. As risk mitigation, I began investigating the resonance features that couple acoustically driven external vibrations to the table surface with transfer functions approaching unity in the several hundred Hz region. The resonance features consist of broad resonances that are likely ISI blade spring and flexure and/or table resonances, with higher-Q resonances riding on them that are likely from components: the GS13 pods, the mass pegs, the individual panels, and the optic structures on the table. The damping planned for other reasons is unlikely to significantly change the Qs of the peaks. We may want to begin developing damping schemes in case this coupling is a problem at HAM6 or elsewhere.

Vibrational coupling, driven by external acoustic noise, was a problem in eLIGO, requiring us to suspend HAM6 steering optics and install blade springs on tip tilts (reduction in 400-550 & 750-900 Hz peaks with suspension). Even with this work, DARM was still somewhat contaminated by acoustically-driven vibrational coupling at the end of S6 (here). Figure 1 shows that there was coherence between the HAM6 geophones and DARM in the 400-550 and 750-900 Hz band late in S6 after our HAM6 interventions. I had hoped that the passive damping planned for the HAMs (for other reasons) would also help reduce the higher frequency motion. However, Guillermo Valdes (UTB), took a recent look at LLO HAM3, which had the damping installed, that made me want to conduct a damping experiment at HAM4.  I found little or no decrease in the Qs of the high-frequency peaks even after I more than doubled the planned tabletop damping (7 dampers instead of 3). Thus I wanted to gain a better understanding of the source of this vibrational coupling in case it is a problem in aLIGO.

The ISI transfer functions from ground motion to table motion suggest an isolation of less than 10 at certain bands in the several hundred Hz region (for example see 500 Hz here). The ISI transfer functions typically show broad horizontal resonances in the 400-550 and 750-900 Hz regions, even before the tables are populated (Figure 2). Modeling by High Precision Devices (G-0701156-00-R) suggested lowest table resonances between 300 and 400 Hz. There are resonances in this region, but the higher frequency resonances are typically more pronounced on the geophone signals. A competing, and, to me, more likely possibility, is that the broad resonances are resonances of the blade springs and flexures, possibly matching table resonances (see resonances of the BSC ISI blade springs here). Geophone spectra show these broad resonances, as well as more narrow resonances riding on top of them (Figure 3). Thus the tallest peaks, the ones that are most likely to contaminate DARM, could be reduced by damping either the broad resonances or the peaks that ride on them. As an example of how the features appeared in DARM during early eLIGO, Figure 4 shows DARM from early S6 with the broad ISI resonances and narrow peaks riding on top. While reducing the broad ISI peaks would have been the best option, reducing the narrow peaks looks like it might have reduced the maximum peak height by a factor of 2 or 3.

In an effort to identify the sources of some of the narrow peaks that ride on the broad resonances, I did a series of tap tests on HAM4. Figure 5 shows that taps on the ISI side pegs for balance masses, the centers of the “X” shaped cutouts in ISI side panels, optic supports on the tables and GS13 pods all excited individual peaks or families of peaks that rode on top of the broader resonances. Figure 6 is a photograph showing these structures. 

Figure 7 shows that each GS13 pod has its own characteristic family of several high-Q peaks. The pods consist of GS13s inside vacuum enclosures. The vacuum enclosures can be heard ringing long after they are tapped. These pod peaks are evident in geophone signals even when there is no tapping. The resonance peaks for a particular pod are largest in signals for the geophone in the pod, but are also evident in signals from other geophones. Fortunately, the frequencies of the geophone pods are, typically, slightly below the broad 400-550 Hz resonance, so it is likely that only a few of the higher frequency pod peaks will be among the highest amplitude peaks that could show up in DARM. Nevertheless, we may want to consider a passive damping scheme for the geophone pods, or a scheme to move the resonances a little lower in frequency.

The individual panels that make up the body of the ISI also have resonances that may coincide in frequency with the broad 400-550 and 750-900 ISI resonances. I took two of the several panel types and suspended them by “strings”. One had resonances at about 400, 700 and 800 Hz, the other at 490 and 670 Hz. Some of the resonances may be associated with the “X” shapes left by the cutouts (see Figure 6). Fabrice and I imagined a couple of passive damping schemes for these, if needed, but access to all of them would be tough and we might just want to instead put damping that is tuned to the 400-550 and 750-900 Hz resonances onto the tabletop structures that touch the beam.

Finally we might want to be thinking about a simple scheme for passive damping  of individual optic structures or the ISI mass pegs.

There may also be ways to damp the broad resonances, such as tuned damping on the blade springs, as the SEI group developed for the bucket peaks in eLIGO, or even active schemes. I would like to repeat my HAM4 work at HAM6 just before it is closed up, so that we have a record of the frequencies of the pods and optics on the surface of HAM6 in case features show up in DARM. It might also make sense to investigate whether blade spring and flexure resonances could produce such high transfer functions. In conclusion, I think we should begin to consider mitigation routes in advance in case this coupling is a problem at HAM6 or elsewhere.

I've made several changes to the TwinCAT code and medm screens for ALS friday and this morning.  The most important thing is that I added the slow feedback from the COMM PLL contrl signal to the IMC VCO.  At the bottom of the COMM PLL screen now there is a section for the Sow feedback, if this is running it replaces the IMC-VCO_SETFREQUENCYOFFSET with an error signal that cancels the error signal from the frequency comparator and replaces it with the PLL control signal, multiplied by a gain.  The gain is currently 10000Hz/V.  This also checks to see if the arm cavity is locked, if the SHG status is OK and if the beatnote stength is above some minimum, and will stop the feedback if there are error conditions.

This seems to be working well as long as the arm cavity has the slow feedback to the top mass active. 

Other updates were adding an error conition to the end station laser locking pll for the noise eater oscillation, fixing the corner state machine, and adding an option to the PDH autolocker to allow it to control the second boost.  medm screens updated were mostly in ALS, except for ISC_CUST_DUAL_PFD.adl

First attempt failed.

• First input/output matrix was put in place by Jax.
• WFS demod dark offset was set.
• Briefly closed the servo and things didn't make sense.
  • WFSA error was zeroed but WFSB not. Cavity was apparently misaligned.
  • Even without the servo, I couldn't flip the sign of WFSB error by tilting ETM and/or ITM.

OL whitening.

See Thomas's entry. ITMX and ETMX are good now.

Demod phase and sensing nonsense.

After Thomas was done with OL, we had to measure sensing matrix again as it uses OL data. Found that demod phase changed, not reliable from measurement to measurement. In the end, I've found that:

• WFS demod phase and the sensing matrix is highly dependent on the cavity alignment or the WFS centering or both.
• I needed to  align the cavity by hand really well and center the WFS to obtain a reliable demod phase.
  • Even then, it looked as if the amplitude of sensing matrix elements varied by maybe a factor of 1.5 or more over 10 minutes time.
• WFSB beam position moves more than WFSA.

The measurement was done by wiggling ETMX at 3.5Hz and ITMX at 1Hz, first in YAW, measuring the demod phase and the sensing matrix for segment 1 and 3, then switch to PIT for 2 and 4. Angle to length shouldn't be a problem as PDH should have a large gain there to squash the length error.

New sensing matrix.

The attached shows one snapshot of demod phase itself on the left screen and the demod phase/sensing matrix measurement on the right.

Two dtt sessions show PIT and YAW. In each dtt window, left is ITM and right is ETM, top shows how Q phase is minimized, middle shows the sensing matrix amplitude in cts/urad (WFS/oplev), bottom shows the sensing matrix phase (should be 0 or +-180) as well as relative phase between diagonal elements (should be +-180).

The sensing matrix phsae still has 10 deg-ish systematic at 1Hz (ITM) and 25 deg-ish at 3.5Hz (ETM). Maybe a decimation filter for OL DQ, maybe something else, definitely not 1:10 whitening, I don't worry about this for now.

PIT.

YAW.

That was it for Friday. I will not work over the weekend at the site.

I added a new GUARD_OVERVIEW screen to the sitemap, accessible from the blue GRD button on the sitemap.

Each block represents a guardian node.  There are place holders for nodes that I expect will show up eventually.  I also expect that more nodes will eventually be added that I haven't accounted for yet.

Each block has a button at the left that will open up the guardian control panel for the node.  The overall background color of the block represents the MODE of the node:

• orange: LOAD
• yellow: PAUSE
• blue: EXEC
• purple: MANAGED
• red: ERROR

There are three indicator lights, which, from left to right indicate:

• is there a notification in the node or not (yellow/green)
• does the current state equal the requested state (orange if not, green otherwise)
• the run status of the current state (various colors depending on the run status)

Blocks that are white indicate nodes that are current not running.

Keita K. informed me that whitening for OLs were off for both ITMX and ETMX and after looking at the spectra, I also agreed. So I went out to the field racks to check that the settings were correct.  

The OpLev whitening boards use a binary I/O daughter board to enable the gain stages.  They looked like they were on the correct settings for two levels of whitening, which matched the de-whitening filters set in software so I unplugged and plugged the board back in and this seemed to solve the problem.  I'm happy that this solved the problem, but I'm perplexed on how it happened.  The daughter boards just plug into the front of the chassis with no screws so it may have been bumped loose, not good.

I'm still investigating when this might have happened but it has some pretty big implications for the relatively new damping scripts that Stefan made, I've sent him an email.

As reported earlier, the IMC guardian code was upgraded.  This upgrade is now fully complete and committed.

The new IMC guardian module is located at:

USERAPPS/ioo/h1/guardian/IMC.py

This new guardian follows a newer paradigm, whereby we follow a slightly less scrict heirarchy:

Rather than three nodes controlling the IMC locking (ISC_IMC, SUS_MC2, IFO_IMC (manager)), we now have just one: IMC.   The SUS_MC2 module is now identical to all other suspensions, without additional controls states for IMC locking.  The IMC guardian module instructs all IMC suspension nodes (SUS_MC{1,2,3}) to go to their ALIGNED states, and monitors those states.  It then controls all of the "LOCKING" filters in the SUS MC2 controller directly.  The result is much simpler code and simpler control.  I expect that we'll use this paradigm for the rest of the ISC control as well.

The trade off is that we need to be much more carefull about defining which channels are under SUS control and which are under ISC control.  Two different guardians should still never touch the same channels.

The new IMC guardian also adds more sophisticated fault checking (for PSL, ISI, and SUS fault conditions), falling into a FAULT state if there is a problem.  This state then uses the new notification feature of guardian to notify the operator of what the problem is.  Once the fault has been cleared, it proceeds back to the state that was previously requested.

Relieving Corey G for a few hours.

- Fil and Luis moving cabling from test stand to BSC10 1:35 PM PT

- Karen cleaning at EY 1:15 PM PT

- Kiwamu doing a DAQ restart 3:01 PM PT

Evan, Yuta, Kiwamu,

Commissioning of the dithering system is underway.

A summary of the red commissioning from this morning:

• We locked the PRMI with the 1f signals and noticed that the lock was fragile.
• Then we realized that the demodulation phase of REFLAIR_RF45 was set back to 133 deg which should be 144.6 deg (see alog 9930) to make the two loops decoupled.
  • This was missing in the guardian
• Once we confirmed that the PRMI can stay locked, we moved on to PRX.
• We started commissioning the dither system (ADS = Alignment Dither System).
  • This is still an ongoing task.

(Alexa, Jeff)

The IMC-X_M1 and IMC-X_M2 wresg calibration filters are off by a minus sign. I have attached the plots depicted in foton and those produced by Jeff's model. The phase is 180 deg in foton, but should be 0 at DC. I have not updated foton, but an email has been sent out to the relevant parties.

The BSC-ISI watchdog plotting software was reported disfunctional by Hugh earlier this week.

I looked into the scripts and they were fine. What I had missed is that Charles had updated the BSC-ISI WD screens, wich thus needed to receive an svn up at the site to match the latest wd_plotting software update, performed when updating the HAM-ISI models last week.

I run the the svn up on: /opt/rtcs/userapps/release/isi/common/medm/ISI_CUST_CHAMBER_WATCHDOg.adl remotely.

The WD plotting software now works on all the SEI platforms of H1.

HAM2 and HAM3 as well as the HEPIs tripped at the exact same time (actuator trip for all of them) @ gps 1077061619 (15:46 PT)

15:47 DAQ Restart. Support of h1lsc model change.

(Jax, Keita)

Yesterday morning we measured the sensing matrix for the ALS WFS. We did this by Injecting 30000cts at 5Hz into H1:SUS-L2_(I/E)TMX_L2_TEST_(P/Y)_EXC, then measuring the transfer function between H1:ALS-X_WFS_(A/B)_I_(PIT/YAW)_OUT and H1:SUS-(I/E)TMX_L3_OPLEV_(PIT/YAW)_OUT. 

In cavity basis:

Pitch Sensing Matrix: (WFS ct/uRad)

Pitch Input Matrix: (uRad/WFS ct)

Pitch Output Matrix:

Yaw Sensing Matrix: (WFS ct/uRad)

Yaw Input Matrix: (uRad/WFS ct)

Yaw Output Matrix:

Raw data: 

Useful information for determining sign conventions from raw data:

1. ETM/ITM Yaw is defined with positive as a counter-clockwise rotation of the optic around the z-axis. 

2. ETM/ITM pitch is defined as positive pitch "down", but ITM oplev is set such that an increase in pitch gives a decrease in oplev measurement.

ETM Yaw:

ETM Pitch:

ITM Yaw:

ITM Pitch:

(Alexa, Sheila, Rana)

PLL Servo Board as per previous alogs..

PDH Servo Board Settings:

• Input 1 enable: ON
• Input 1 polarity: POS
• Input 1 gain: -7dB
• Common Comp: ON
• Boost 1: ON
• Boost 2: ON unless specified

Transfer Functions:

1. Frequency: 24.407363 MHz, Demod phase: 120.7 deg (228 steps): SCRN0343.TXT (mag), SCRN0344.TXT (phase)
2. Frequency: 24.407363 MHz, Demod phase: 140.7 deg (266 steps): SCRN0345.TXT (mag), SCRN0346.TXT (phase)
3. Frequency: 24.407363 MHz, Demod phase: 100 deg (190 steps): SCRN0348.TXT (mag), SCRN0347.TXT (phase)
4. Frequency: 24.407363 MHz, Demod phase: 80 deg (152 steps): GIF 349  ---- each measurement was different
5. Frequency: 24.402363 MHz, Demod phase: 120.7 deg (228 steps): SCRN0354.TXT (mag), SCRN0355.TXT (phase)
6. Frequency: 24.401363 MHz, Demod phase: 120.7 deg (228 steps): SCRN0356.TXT (mag), SCRN0357.TXT (phase)
7. Frequency: 24.387319 MHz, Demod phase: 120.7 deg (228 steps): SCRN0358.TXT (mag), SCRN0359.TXT (phase) --- bistable mode, hops to 01 mode

I have attached two plots summarzing the above results. One plot consists of OLTFs where the modulation frequency was held at 24.407363 MHz and the demon phase as was adjusted (EX_PDH_OLTF_DiffDemodPhase.pdf), while the other plot has the demod phase held at 120.7deg (228 steps), while the modulation frequency was adjusted (EX_PDH_OLTF_DiffModFreq.pdf).

Amplitude Spectrum (from IMON) --- Freqency: 24.407363 MHz, Demod phase: 120.7 deg (228 steps)

1. Boost 2 Off: EX_PDH_NoiseSpectrum_BoostOff.TXT
2. Boost 2 On: EX_PDH_NoiseSpectrum_BoostOn.TXT, EX_PDH_NoiseSpectrum_BoostOn_Low.TXT

The BS IS tripped on GS-13 watchdog at 1328 utc this morning.  Traffic, wind, something--plotting scripts still not functioning...

Anyway, I brought it back to lvl2 with 750mHz blends on stage2 and T250s on all Stage1 blends except T100mHz_0.44 blends on X & Y dofs.

I reset the target positions, there was about 700nrads on RX and <4um on Z, all other shifts were less.   Please let us know if this impacts any alignments.  This allowed for a one button isolation.