Ran HEPI pressure sensor cables from mechanical room to BSC chambers at both end stations. 

IM4 was scanned in YAW while the DC SUM of various sensors were recorded, and it's apparent that there's a clipping.

In the attached, red, blue and green represent normalized DC SUM of the POP_A, POP_B and AS_C respectively plotted against IM4 YAW slider offset. Blue vertical line at -8520.7 shows the alignment we were at this morning.

There appears to be a hard edge on the left side on the plot that is common to the sled and the AS_C, and I guess that's the baffle in front of the PR2.

We're already very close to the edge. From the red and blue data at the blue vertical line, the single trip loss is either 0.3% (red) or 0.7% (blue), and you need to double the number for a round trip loss.

If we go somewhat to the left on the plot, you're already dead. I propose to move somewhat to the right.

The fact that AS_C shows somewhat different pattern means that there's some other clipping going on for the SRC path, on top of the PR2 baffle.

In the plot, Relative power=1 simply means that the measured power was the highest.

Ran field cables for PCAL electronics at EY including power cables. Items that still need to be completed:

1. Install in-rack cabling at Pcal Transmitter Pylon
2. Finish terminating field cables

08:28 - 08:53 cdsfs0 down
08:56 Joe G. to LVEA to retrieve PCAL viewport protector from shelf
09:02 Aaron to pull cables for PCAL (WP 4896)
09:03 Filiberto to end X and end Y to pull cables for HEPI pressure sensors (WP 4905)
09:04 Ed to end X and end Y to check ESD AI chassis filter board versions (WP 4902)
09:11 Jeff B. and Andres looking for parts in optics lab
09:14 John hard-closing GV18 for PCAL viewport protector replacement work (WP 4903)
09:17 Joe G. and Rick to end Y to replace PCAL viewport protector (WP 4903)
09:28 Hugh troubleshooting sensor problem at ITMX (WP 4899)
09:31 Sudarshan and Shivaraj to end X to work on PCAL cabling
09:36 Jeff K. making changes to end X ISI and HEPI models, restarting models
09:40 Contractor to see Bubba and John
09:54 Jeff B. and Andres done in optics lab
10:01 Jeff K. done with model changes and restarts, ready for DAQ restart
10:13 Joe G. and Rick done replacing PCAL viewport protector
10:22 Richard to LVEA to trace HEPI pressure sensor cables
10:29 Unifirst delivery
10:29 Cyrus working on h1broadcast0, restarting
10:31 Kyle reopening GV18
10:35 DAQ restart, error from duplicate channels in Beckhoff
10:58 Richard routing HEPI pressure sensor cables
11:00 Ed done, replaced both boards
11:00 Hugh back to BSC2
11:23 Cyrus done work on h1broadcast0
11:24 Richard done routing HEPI pressure sensor cables
11:44 Daniel done making Beckhoff changes (WP 4904)
11:48 Hugh done in LVEA
13:09 Kyle and John running purge air compressor at end Y (WP 4907)
13:09 Doug and Jason retrieving parts from LVEA
13:42 Doug and Jason done retrieving parts
13:44 Doug and Jason to end Y to realign optical lever
14:08 Ed to SUS test stand, checking UIM chassis
14:20 Doug and Jason done aligning end Y optical lever
15:18 Shivaraj and Patrick updating PCAL Beckhoff code at end X
15:20 Kyle and John done running purge air compressor at end Y

J. Kissel, K. Venkateswara

As described in LHO aLOG 14521, we've added an IPC connection from top-level of ISI to HPI for the GND super-sensor to be used for sensor correction to the h1isietmx and h1hpietmx front end models. In addition, we've cleaned up the few channels:
-  H1:ISI-GND_BRS_ETMX_DAMPCTRLMON1 --> H1:ISI-GND_BRS_ETMX_DAMPCTRLMON
-  H1:ISI-GND_SENSCOR_ROTVELCORR --> H1:ISI-GND_SENSCOR_ETMX_STS_X_ROTVEL
-  H1:ISI-GND_SENSCOR_TORQUECORR --> H1:ISI-GND_SENSCOR_ETMX_STS_X_TORQUE
Finally, we've updated the BRS OVERVIEW screen to reflect the new channel changes, and confirmed that both ISI and HPI see the tilt-corrected ground super sensor in STSC,
H1:HPI-ETMX_STSINF_C_X_OUT   or
H1:ISI-ETMX_ST1_GNDSTSINF_C_X_OUT
calibrated into 1 [(nm/s) / ct] (above 4 [mHz] is you really care that low). Note that this requires the calibration filters in the GNDSTSINF X bank to be turned OFF.

This change required 
- Making sure the current configuration sticks
     - Capture of a new safe.snap
     - Commit the current filter file
- Recompiling, Reinstalling, Restarting, Restoring the h1isietmx and h1hpietmx models
- Restart of the frame builder / data concentrator / h1dc0
- Committing h1isietmx and h1hpietmx top-level models to the userapps repo.

This opens and closes Work Permit 4906.


P.S. Unfortunately, I didn't realize until writing this aLOG that because of our "store the GND STSs once and only once" policy, we're not storing any of the ETMX STS C channels separately in the frames. The only version of the tilt-corrected GND super-sensor stored in the frames (and regrettably only in the commissioning frames) is 
H1:ISI-ETMX_ST1_SENSCOR_GND_STS_X_IIRHP_IN_DQ   or
H1:HPI-ETMX_SENSCOR_X_FIR_IN1_DQ
which is after the H1:HPI-ETMX_STS_INMTRX, or H1:ISI-ETMX_ST1_STS_INMTRX, so it relies on the matrix being selected to use STS C in the X direction. This is currently the case, but we'll most likely consider added a separate test point and channel in the GND_SENSCOR bank next week.

Testing modifications to the purge-air system in preparation for Rai's ionizer work at BSC10 next week

Krishna pointed out last night/ this morning that the new IIR filter we are using for sensor correction at ETMX was designed around an STS-2. We have a T240 at EX, so we needed to adjust the filter some. Basically, we just divided all of the frequencies of all poles/zeros by 2 to approximate the shift from a 8mhz sensor to a 4mhz sensor. This was done for X and Z on the ISI, but just X on HEPI. If we use Z senscor on HEPI, this change will need to be copied over. If we use this filter at the corner or EY, we will have to remember to reverse the change to work with STS's again.

Basically we turned the original istalled IIR:

zpk(-2*pi*[0 0 0 0.01 pair(0.09,50)],-2*pi*[0.005 pair(0.03,65),pair(0.01,70),pair(0.07,50)],1)

into:

zpk(-2*pi*[0 0 0 0.005 pair(0.045,50)],-2*pi*[0.0025 pair(0.015,65),pair(0.005,70),pair(0.035,50)],1)

Latest news from the OMC:

==== Beam stabilization at the dark port ====

To keep the beam centered on the both the AS WFS and the OMC, I recalculated the actuation matrix for the OMC alignment loops, following Koji's calculations in T1400585.  Instead of using OM1 and OM3 for the alignment control, now we use OM1 and OM2, so that all of the control is upstream of the WFS.  This works very well; the low-frequency beam motion on the WFS is suppressed by 10x or more.  In the first plot attached the solid lines (references) are without the OMC alignment loops engaged, the dashed curves are with the OMC QPD servo on.  It doesn't look as though ASC-DC loops from the WFS --> OMs are necessary, but this may change when the dark port is dominated by higher-order modes (all this work was in a single-bounce configuration).  In principle any motion of the OMC suspension relative to the WFS will not be suppressed, from the point of view of the WFS, since the OMC QPDs are on the OMC breadboard, and the WFS are fixed to the table.

Anyways if you want to keep the beam centered on the AS WFS, you can set the OMC guardian to the 'ASC_QPD_ON' state.  The guardian control should be robust in the event of locklosses (if there's no light on the QPDs it will run the OMC down script and wait for the beam to return).  Note that if cavities are moving through fringes this will screw everything up, so maybe it makes sense to have the OMC guardian managed by the DRMI when ASC loops are being tuned.

==== Offset locking state for the OMC (also some gain swapping) ====

To measure the length noise in the OMC I added another state to the OMC guardian, OFFSET_LOCK, that moves the lock halfway off-resonance.  The procedure follows what Zach outlined at LLO.  I found some gotchas that had to be solved: the high-pass filter on the input to the LSC demod needs to be turned off, and the DCPD normalization has a *lower* saturation limit at 0.1 that will totally ruin the DCPD NORM signal for small transmitted power on the DCPDs.  (The overall dc gain in the DCPD A and B filter banks is -122.4dB, so we hit the lower limit pretty easily.)  To keep us from hitting the lower rail, I moved a gain factor of 1000 from the DCPD SUM filter bank to the DCPDs themselves, this keeps the output of DCPD_NORM_FILTER above the lower saturation limit.  The NORM channel is used for the OMC LSC and the SUM (which previously had the 1000x gain, now moved upstream) is sent to the IFO LSC, but the change is common to both DCPDs, and the overall SUM signal hasn't changed, so this adjustment should be transparent downstream of the DCPD conditioning.

==== OMC stability over several hours ====

Last night the OMC was locked on a single bounce from ITMY for about eight hours.  The PZT control drifted by 2V, slowly approaching an equilibrium state, and there was no change in the transmitted power.  (There was a small earthquake just after 0900 UTC that caused some noise in the DCPD SUM.)  It relocked a couple of times on its own in the morning.  This is with the QPD servo enabled, not the dither, so the alignment stability is somewhat better than what we'll use for the full IFO.

A 2V change in the PZT drive corresponds to a 28nm change in the cavity length (from T1000276).  The DCPD SUM channel should be calibrated for mA (I think), and for a single-bounce beam with 10W input to the IMC there should be about 19mW at the dark port.  To do: calculate the expected change in cavity length and the time constant to see if this 2V shift in drive is what we expect from thermal expansion of the breadboard.

==== OMC LSC demod phase ====

I repeated Nic's measurement of the demodulation phase for the OMC LSC dither loop.  With the OMC LSC loop open, I moved the PZT slightly off resonance, turned on a 100Hz excitation in PZT1, and adjusted the demod phase so that the ratio of the I-phase / Q-phase was maximized.  I found a phase of 70deg was optimal; this is quite a bit off from Nic's observation of 120deg.  I'm not sure how different our methods were, or whether a drift of ~50deg over ~2 months is something we should expect.  We'll keep an eye on this phase and see if it keeps changing.

Patrick, Shivaraj

Opened remote desktop to h1ecatx1
Ran svn update for C:SlowControls
Opened TwinCAT Target Configuration GUI
Selected H1ECATX1, PLC3
Ran 'Stop', 'Update from source', 'Compile' and 'Activate and run'. No errors.
Noticed all channels went white/invalid for end X Beckhoff
Ran 'exit' in the IOC.
Ran 'Restart EPICS database' in the TwinCAT Target Configuration GUI. Channels recovered.

Burtrestored h1ecatx1 PLC1, PLC2 and PLC3 to 14:10 today.

re 14488, I switched the ITMX H1 L4Cs and saw that the large L4C offset stays with the channel and not with the sensor itself.  With the Pier Pod powered off, the epics reading remains at -4300cts so the problem is down stream of the Pier Pod.  McCarthy and I will revisit this next week or whenever we can.

The IPS problem noted in 14488 has not resolved although I thought I had found a problem.  The sensor flag stands between the IPS sensor element pair and it looked like the flag was touching the Sensor Holster wall--I was unable to slip a piece of paper between them.  I've spotted this on a few Actuators and thought rubbing was the problem.  However, attached is Spectra taken at 1230 today and there is little changed even though I had made sure it was well clear.  There is another potential rubbing spot (right near by) but I failed to look this morning.  See the second attachment here where I point to the two rubbing locations.

Reset HAM2, HAM3, HAM4, HAM5, BS and ETMY.

The UIM Chassis S0900300 was removed from the Quad test stand to be modified in compliance with E1400164. It will be returned after a full set of TFs and Noise measurements have been recorded.

Doug, Jason

Re-aligned the ETMy optical lever this afternoon, approximately 1400 PDT.

The BSC-ISI overview screen was updated to add a missing column on the STS2CART matrix display. The new screen was commited under the svn:

/opt/rtcds/userapps/release/isi/common/medm/bscisi/ISI_CUST_CHAMBER_OVERVIEW.adl  -r8929

Added 660 channels (including guardian channels)
Removed 36 channels

Goals:

I have been looking into recent data in order to:

- compare the performance form units to units

- correlate ISI stage 1 performance with optical lever motions

- compare winday times with regular times

Plots Desciption:

There are 4 figures attached. Each one display one hour of data.

- The first figure is for the windy afternoon on Saturday October 11th reported by Sheila

- The second figure is for Sunday October 19th at 3am

- The second figure is for Monday October 20th at 3am

- The second figure is for this morning, October 21st at 3am

In each of the four plots attached:

- the three plots in the top row show the ISI longitudinal motion (along the arm axis). Left plot is time series, middle is ASD, right is RMS.

- the three plots in the middle row show the optical lever pitch motion. (Left plot is time series, middle is ASD, right is RMS.)

- the three plots in the Bottom row show the optical lever pitch motion. (Left plot is time series, middle is ASD, right is RMS.)

Comments:

Windy day (first plot):

In the first plot (windy day), the ISI stage 1 RMS motion is about 10 times higher than usual, around 1000 nm/s RMS instead to about 100 nm/s in normal days. The Stage 1 motion is dominated by features below 50 mHz, most likely tilt as reported by Krishna.

The optical lever pitch motion is about a factor of 3 or 4 higher than usual (around 100 nRar instead of a few tens). Though the ISI is shaking at 50 mHz, the RMS of the optical lever is still dominated by the suspension mode at 0.5 Hz. 

ETMY test mass pitch is moving twice as much as the others. This can clearly be correlated with the ISI motion at the suspension modes. We need to look into ETMY (something wrong in the blend? not enough loop gain? sensor noise?)

The test masses Yaw motion is dominated by features at the micro-seism, that are probably self inflicted (see comments for the third plot). ISI low performence on ETMY between 0.2 Hz and 1 Hz also affects the performance of the Yaw motion of this test mass.

Regular input motion, night time (second plot):

The ISI motion is pretty consistent from chamber to chamber, except for ETMY that should perform better above 0.25 Hz.

The Pitch motion of all test masses is dominated by the 0.5 Hz suspension mode.

The Yaw motion of all test masses is dominated by the micro-seism.

ISI off:

the third plot (data taken yesterday night) is quite interesting, as it looks like ITMY ISI was damped only.

In this configuration, ITMY pitch RMS motion is 10 times higher than the other units (near 1000 nrad RMS)

The Yaw motion is much lower (tens of nrad), but the three units isolated don't perform better than the unit damped. The unit damped is dominated by suspension modes features. The units isolated are dominated by micro-seism features.

Fourth plot (this morning at 3 amd);

all ISI are ON. They all perform similarly at low frequencies (below 0.5Hz), but optical levers RMS values are high and not consitent from units to units. Maybe some commissioning activities... to be checked.

Conclusion:

- we need to look into ETMY, and improve its performance at the suspension frequencies

- on windy times, and assuming alignment is the priority: for reducing the test masses pitch RMS value, we might want to try to improve the ISI performance at 0.5 Hz at the cost of further increasing the very low frequency motion. For yaw, we need to reduce the self inflicted amplification at the micro-seism.

- on regular times, we need to reduce the apparently self-inflicted yaw motion at the micro-seism

Alexa, Evan, Kiwamu

We observed some new features which are related to the SRC mode hopping.

• We noticed that when SRM was slightly misaligned from the optimum angle in pithc by approximately 15 urad, it seems to reduce the number of mode hops in SRC.
  • Of course, this reduced the power build up in the signal recycling cavity by some amount, but it was more stable due less mode hoppings.
• We starting putting an offset in the SRC operating point in order to study if the signal really has multiple zero crossings.
  • When LSC-SRCL had an offset of -800 cnts it became much more stable than it was in the 10 W configuration. We could even stably go to -5000 cnts by expanding the linear range by the normalization with AS_RF90.
  • On the other hand, when we went to the positive side in the offset (e.g. ~ 400 conts), we could easily lose the lock due to the instability or the hopping.
  • This indicates that the error signal for SRCL is asymmetrical about 00-mode's zero crossing.
• We checked the same asymmetrical error signal both in 10 W and 1 W configurations and found that the instability seemed to be further away from the 00-mode in the case of 1 W.
• We also checked the level of RFAM in all the REFL detectors by directly detecting the prompt reflection of PRM while the interferometer was misaligned.
  • Even though both in-vac and in-air RF45_I signals showed a discrete jump in the RFAM offset, the amount of the offsets were much smaller -- the biggest offset was about -22 cnts in REFL_A_RF45_I.
  • Apart from REFL_RF45s, all the detectors seemed to have a linar relation in the RFAM offsets with respect to the PSL power.
• Note that we had to re-align the DRMI after three lock or so losses. Otherwise, we were not able to smoothly acquire the lock.