Kiwamu, Stefan, Dave O,  Elli

Power spectrum from last night's lock attempt as detailed in alog entry 15323.

Comparing BSC and SRM control signals at cavity buildup of 75 at GPS 1101128136 and cavity buildup of 115 at GPS 1101128173.

There is a broadband increase in both control signals, including an increase at the 60Hz periscope peak.

no restarts reported.

conlog frequently changing channel log attached

Kiwamu, Stefan, Matt, Lisa

Since Valera called us to announce the LLO 50 Mpc and kindly encouraged us to catch up, we didn't want to let him down, and we decided to keep going.

Details are in  the previous entry , here are a couple of plots with the latest CARM offset reduction and power build up (TR_Y_QPD is 1 for single arm). REFL DC is going down and REFL 9I is going up as they should (first plot). BS control becomes unhappy in the latest step of the CARM offset reduction (see second plot). We were greedy (and sleepy) and we didn't measure anything on our way up, some loop measurements are the next thing in the list. 

Getting close..tomorrow there could be even more to be thankful for.

P.S.: We still need to check our power and offset calibration.

Kiwamu, Lisa, Matt, Stefan

- First we verified that the CARM to transmitted light transition still works today (arm power 0.32*single arm).
- Next we repeated the transition to AS_45_Q, and turned on the gain scaling (arm power 2.0*single arm).
- We also immediately turn on AS_45_Q gain scaling with TR_X  (arm power 2.0*single arm).
- Then we turned on the DHARD WFS  (arm power 2.0*single arm):
   whitening gain of 9dB: H1:ASC-AS_B_RF45_WHITEN_GAIN 3
   H1:ASC-AS_B_RF45_Q_PIT_GAIN and H1:ASC-AS_B_RF45_Q_YAW_GAIN gain to 0.1
   input matrix AS_B_RF49Q to DHARD H1:ASC-INMATRIX_P_8_6 1e-4, same for yaw
   H1:ASC-DHARD_P_GAIN 0.3 , same for yaw
   control filter modules FM1 (integrator) and FM5 (Low pass LP0.2)
   output matrix: H1:ASC-OUTMATRIX_P_7_8 = 1   ,  H1:ASC-OUTMATRIX_P_8_8 = -1  ,  H1:ASC-OUTMATRIX_Y_7_8 = 1   ,  H1:ASC-OUTMATRIX_Y_8_8 = 1
- Then we went to a hgher arm power (arm power 32*single arm).
- We noticed that TR_X starts saturating right around there, so we intended to switch to the QPDS, but had an unreasonable amount of trouble for this simple operation.
- Still trying...

Attached is a plot of the CARM transfer function. It also includes a transmitted power ratio of the QPD's and the LSC PD's.

The ALS_COMM and ALS_DIFF FIND_IR algorithms have not been working over the last few days, but they have been taking a lot of time to fail.

This evening we rewrote them both.  ALS_DIFF has a nice algorithm which tries the known good locations quickly, and if that doesn't work it searches around those locations.  Unfortunately, the search part has only been tested a few times, because the initial quick check of known locations usually works.

For ALS_COMM, we didn't bother with a search feature.  The known good locations are checked, and if that fails (which is rare) it asks for help from the user.  It would be good to better test the search functionality of ALS_DIFF, and then make ALS_COMM have something similar just to deal with the rare cases in which the known locations fail.

For initial alignment, and transmon pointing onto the baffle PDs in particular, we have a new script.

in /opt/rtcds/userapps/release/asc/h1/scripts there is

• ditherAlign.py which has top level functions for TMSX and TMSY (and place holders for the ITMs) - this can be called from the command line e.g., ./ditherAlign.py TMSX
• baffleAlign.py contains functions for aligning optics to baffle PDs - it includes a very coarse spiral search, a dither alignment, and higher level combinations of these
• slowDemod.py contains ultility functions for dithering and demodulation using EPICS (yes, I know its bad, but what else?  and it works for freqencies below 4Hz...)
• testDemod.py for testing slowDemod.py

When the TMSs are close to the correct position, the dither alignment takes less than 1 minute.  When they are way off, it takes a few minutes.

This should be extended to the ITMs and ETMs to help find them when they are really lost.  Once it is working well, we should move these into the IAS guardians.

Summary:

There are some strange things, but in summary,

WFSA is more sensitive to the hard mode (arm axis rotation at around the center of the arm) than the soft (arm axis translation).

WFSB's sensitivity to the hard mode is smaller than WFSA by a factor of 5 or so. Also, WFSB is somewhat more sensitive to the soft than WFSA.

This means that we can use WFSB as the soft mode sensor and feed back to TMSX (because TMS causes the soft and the hard mode with comparable normalized amplitude at the same time), while using WFSA as the hard mode sensor to feed back to e.g. ITMX. Then we can use the ITMX camera image to slowly feed back to the ETMX to fix the beam position on ITMX. Or you can do fancier diagonalization but you get the idea.

Details:

In the attached, the right most plot shows the response of WFSA and WFSB against EX and IX PIT motion.

You can see that WFSA's response is much larger than WFSB. You also see that WFSA only goes down when you tilt EX, but that's not the case for IX (why?).

The middle plot shows you both PIT and YAW response. Again WFSA is much more sensitive than WFSB.

The left plot is the response against TMS in YAW (didn't have time to do PIT), and you see that the WFSB response is about twice as large as WFSA.

Both ETM and ITM causes mostly the hard mode motion because the cavity is close to concentric.

OTOH TMS causes both the hard and the soft mode motion at the same time.

So, all in all, these appear to mean that WFSA is more or less the hard mode sensor, and WFSB is the soft one.

SEI working on BSC2
Commissioning work on X-arm
Working happening over the break will require work permits
Apollo working on cabling outside and in the VPW
EE working in H2 building

9:30 Corey Craning in LVEA, done 13:30
10:00 Sudarshan to LVEA
10:45 Richard to LVEA
13:45 Corey back to LVEA
14:00 DaveB to CER, both Mids, back at 14:30
14:00 Richard and Vern to CER

Vern and Richard re-installed the TCS X  rotation stage interface board with the protection diodes removed.

Dave Ottaway, Elli

 For the X-end green WFS, we adjusted the WFS autocentering gain to match the Y-end WFS.  The updated values are:

H1ALS-X_A_AUTOC_PIT_CTRL_GAIN: 200,000

H1ALS-X_A_AUTOC_YAW_CTRL_GAIN: -150,000

H1ALS-X_B_AUTOC_PIT_CTRL_GAIN: 70,000

H1ALS-X_B_AUTOC_YAW_CTRL_GAIN: 70,000

The unity gain frequency at the for the X-end WFS is:

WFS A PITCH: 15 Hz

WFS A YAW: 15 Hz

WFS B PITCH: 6 Hz

WFS B YAW: 7 Hz

And the unity gain frequency at the Y-end:

WFS A PITCH: 10 Hz

WFS A YAW: 10 Hz

WFS B PITCH: 7.5 Hz

WFS B YAW: 7 Hz

Ed, Keita, Jeff

So, a quick and nasty coherence check just to find possible dead monitor channels using a couple of frequencies reveals apparent bad channels:

ETMY M0: SD - voltmon, fastimon

           R0: F1 - noisemon

           L2: All Channels? - noisemon

ITMY  L1: UR fastimon

All suspensions in Y-Arm from TMS back to ITM were tested. Any not specified here measured good.

The fact that ETMY L1 shows apparent DC offsets, in the -4300 ct range in all noisemon channels, UL voltmon and LR fastimon, is not revealed by this measurement.

The contractors will not be working on the new DCS addition during the Thanksgiving holiday, 11/27-11/30. They will return on 12/1.

The frontend laser watchdog was re-activated.  For reasons unknown it was switched off around
midnight on 11/11.

I'll go through and review to make sure nothing has been reverted or missed but this should be the last HEPI matrices to be corrected, at least those that really affect current operation and positional studies.

The rotation and pringle dofs had magnitude errors of x2 & x4 and the output (CART2ACT) matrix was all 1s.  See the first attachment for the before (left) and correct (right) values.

The second attachment shows the times series as the platforms were taken down, the matrices corrected (shifting the Cartesian readings) and bringing things back up.  No issues in that process: the ISI ST2 was already just damping, ST1 was brought down to damping and then the HEPI deisolated.  Matrices updated, RZ Reference Location corrected, new filters loaded, HEPI and ISI reisolated.  I tweaked the yaw position a few 100nrads to recover the exact OpLev output.  Brough the system backdown to take a safe.snap and then reisolated. By the way, the Pitch & Yaw are correct.

The final two attachments are the before controllers and the new 4hz UGF generic controllers.  The TF data going into these are from H2 ETMY but I still looked at them and with some phase margins in the lower 20degrees and some gain peaking near 3 using a 5hz UGF, I lowered the UGF to 4hz and now the phase margins are lowest in the upper 20s and the worst gain peaking is just over 2.

Updated safe.snap and new foton file committed to svn.

Initial attempts to take undamped TFs on ITMX & ITMY exhibited rung up P & R modes (see LHO aLOG entry 14653). For the next attempt, fine tuning of excitation amplitudes was necessary to avoid ringing up these modes.

Phase 3b (in-vacuum) undamped TF measurements have been taken for ITMX & ITMY (QUAD) suspensions as follows:-  

- ITMX M0-M0 undamped results (2014-10-30_0700_H1SUSITMX_M0_ALL_TFs.pdf)
- ITMX R0-R0 undamped results (2014-10-30_0700_H1SUSITMX_R0_ALL_TFs.pdf)
- ITMY M0-M0 undamped results (2014-10-28_1200_H1SUSITMY_M0_ALL_TFs.pdf)
- ITMY R0-R0 undamped results (2014-10-28_1200_H1SUSITMY_R0_ALL_TFs.pdf)

ISI Status: ISI's damped and FULLY_ISOLATED via Guardian.

ITMX & ITMY undamped TFs above have been compared with other similar QUADs at the same phase of testing (allquads_2014-10-30_AllQUADS_Doff_Phase3b_ALL_ZOOMED_TFs.pdf). The plot key is as follows:-

Blue Trace = Model Prediction (fiber/thincp).
Orange Trace = L1 ITMX (fiber 2013−09−04), Phase 3b.
Black Trace = L1 ITMY (fiber 2013−09−05), Phase 3b.
Magenta Trace = H1 ITMY (fiber 2014−10−28), Phase 3b.
Cyan Trace = H1 ITMX (fiber 2014−10−30), Phase 3b.

Summary:

M0-M0, main chain TFs are a very good fit to the model, for all DOFs, with only some minor cross-couplings from P2V.

R0-R0, reaction chain TFs agree with the model predictions and are consistent with similar QUADs. The largest deviation from the model can be seen with the ~1.45 Hz P mode, a consequence of the harness routing stiffening the suspension, seen before. Some minor cross-couplings are also present: from P2L, P2R, and P2V only for ITMY. Damped TFs should be taken to verify that damping loops suppress these cross-couplings.

All data, scripts and plots have been committed to the sus svn as of this entry.