J. Kissel

Using the refined H1 SUS BS OPTICALIGN alignment offset slider calibration (see LHO aLOG 14321), I've refined the calibration of the optical levers using the same method as with the ITMs (see LHO aLOG 14312), by moving the well-calibrated sliders and tracking the optical lever motion. Attached are the fitted slopes to this motion, which indicate that the new optical lever calibrations should be 

BS P     141 [urad/ct]
BS Y     231.9 [urad/ct]
as with the ITMs, Pitch has been corrected by a factor close to 2, where yaw needs only a ~15% correction.

Because the optical lever damping is actively used, I'll wait until tomorrow morning to install the new calibrations and adjust the loop gains accordingly.

Details:
-----------
- Step through several alignment offset values (in [urad]), record DC optical lever output (in ["urad"], the quotes indicating the to-be-refined units). I chose to get a smattering of offsets between +/- 20 [urad] surrounding the currently saved "ALIGNED" values.
- Fit slope of data points to a line (see attached). The calibration corrections are
       ["urad"/urad]    [urad/"urad"]
BS P        1.901           0.526
BS Y        1.156           0.8654

         Previous Cal  *  Correction          = New Cal
BS P   268 ["urad"/ct] * 0.526 [urad/"urad"]  = 141   [urad/ct]
BS Y   268 ["urad"/ct] * 0.8654 [urad/"urad"] = 231.9 [urad/ct]

re my 14373 entry, I figured I could correct these to the T1000388 even though there is a "Check the signs" Note in the doc as Fabrice says we'll just change the signs in the sym filters.

The matrix had correct elements in the primary transformations; only some of the cross coupling elements were variant.  I went ahead and ran the populate matrices medm script.  It crashed as it tried to load CPSALIGN values which are not in the data file.  Makes me wonder how the GS13 & CART2ACT values got loaded before...  So, I moved the CPSALIGN load section to the end and ran the script again.  I then confirmed all the matrices complied with the T1000388--all good.  Then confirmed the ISI still isolated--yes.

Then with the ISI just damped and HEPI not isolating( no Pos loops,) I drove HEPI in Z with a random noise signal band passed between .1 and 1 hz.  Monitoring the HEPI L4Cs and the ISI Stage0 L4Cs, see attached, it appears that the vertical sensors are out of phase.  So it seems we need that sign change in the SYM filters.

Made and committed safe.snap file.

Commissioners wanted the machine back before I could do other dof measurements, maybe I can do them with passive TFs.  Either way, later.

no restarts reported

Jason, Sheila

There have been some glitches on the ETMX oplev, which don't seem to correspond to motion of the optic, the attached screen shot shows an example.  I think that I have seen glitches like this that were much larger in amplitude, but am not sure. 

One question for detchar is if they have a tool that can search for glitches like these, and give us some information about how often they are happening, how large they are, and maybe monitor to see if they are happening on other op levs. 

Another issue is that sometimes the lasers fail, which is often foretold by a several seconds oscillation in the oplev sum.  Can detchar set up some kind of monitoring for that?

Of course the real question is how can we fix it......

Awaiting discussion with JRollins before committing to svn.

Before the earth quake hit us tonight, (magnitude 6.8 in the pacific) we worked on ASC for DRMI.  We started out using PRMI, but since our DRMI lock was much more stable today than it had been last night, we switched to just locking DRMI.  We suceeding in closing two loops from REFL 9 A to PRM, for PIT we used a gain of -1e-4 for yaw we used a gain of 1e-4.  Then the earth quake hit, now all 4 test mass ISIs are tripped. 

9:15 Krishna & Richard to EX ground BRS
9:15 Jason & Doug to LVEA, cleaning up IAS equipment
13:30 Gerardo & PK to h2 laser enclosure
14:15 Jeff B to LVEA suspensions work done at 15:30
 

The local sensors, both positional and inertial, are converted to Ligo Global Frame (assuming the Z_L & Z_G are collocated, which they are not, quite) via calibration filters and local to cartesian transformation matrices; this is done using the right hand rule, RHR.  Many of the platforms for H1 were commissioned before much thought and diligence was put into these matrices.  The seismic group has finalized these transforms and we can now correct the long standing errors. However, this will require taking platforms off line to load the matrices as well as new cartesian basis controllers and Position Targets for many of the platforms.  We'll attempt to do this systematically during maintenance days and other opportunities.

Meanwhile, as I just finished an update to the state of these matrices, I thought a tabulation of the platforms was in order.

Summary: It works consistently without remeasuring the sensing matrix everyday and some other nonsense.

The current setup (which will change in the future) is this:

• QPD centering is turned off.
• WFS centering is turned on.
• WFS is fed back to PZT mirrors (i.e. the beam is aligned to the cavity).
• ITMY green camera centroid output is copied to the frontend over EPICS using /ligo/lho/scripts/cameracopyY script.
• ITMY centering error signal goes to ASC via ALS WFS_DOF1 (which is strangely named AWFS3 in the ASC MEDM).
• Centering error goes back to the ETM and ITM such that the ETMY beam position is not affected.
• ETMY beam position is uncontrolled, which is not good. Probably some change is necessary.

The screen shot shows the current settings.

Other things:

In the same screen shot, the strip tool shows that the demise of the WFS centering is the demise of this system. Blue trace is one of the outputs of the WFS centering, and as soon as it starts to hit the bottom rail everything becomes ratty and eventually it breaks lock. I'll change the table layout to get more juice out of the PZT mirror range.

When it unlocks, a large transient from the centroid thing hits both ETMY and ITMY, so you need to wait for maybe 30 seconds until it becomes possible to lock again.

You want to reset the WFS centering servo (which may or may not grab) and enable the WFS again, and most of the time it goes back to a good alignment. Sometimes WFS centering never recovers by this procedure. If that happens, you might want to zero the ASC output to the ETMY and ITMY and do it again.

Yesterday I surveyed the CPS grounding systems and found the ITMY racks lacking anything explicit.  There is of course, in theory, grounding by virtue of the rack sitting directly on the unistut attached to the chamber.  However, as per T1300871, the grounding is expected to be from the board 'Target Ground' lugs to the chamber.  At noon yesterday, I added this to the three BSC1 CPS racks.

Below is spectra from Tuesday am and Wednesday am so a before and after view.  The Blends are in the same state (PCOMM JimW) and we are in all ways, in the same configuration.  The ground motion could be different of course.

Please look at the attached pdf file.

model restarts logged for Tue 07/Oct/2014
2014_10_07 08:44 h1iscey
2014_10_07 08:54 h1iscey
2014_10_07 09:07 h1iscey
2014_10_07 09:10 h1asc
2014_10_07 09:21 h1iscex
2014_10_07 09:35 h1asc
2014_10_07 09:35 h1iscex
2014_10_07 09:35 h1iscey
2014_10_07 11:05 h1calex
2014_10_07 11:05 h1iopiscex
2014_10_07 11:05 h1iscex
2014_10_07 11:05 h1odcx
2014_10_07 11:05 h1pemex
2014_10_07 11:59 h1broadcast0
2014_10_07 11:59 h1caley
2014_10_07 11:59 h1dc0
2014_10_07 11:59 h1fw0
2014_10_07 11:59 h1fw1
2014_10_07 11:59 h1iopiscey
2014_10_07 11:59 h1iscey
2014_10_07 11:59 h1nds0
2014_10_07 11:59 h1nds1
2014_10_07 11:59 h1odcy
2014_10_07 11:59 h1pemey
2014_10_07 12:39 h1iopiscey
2014_10_07 12:41 h1caley
2014_10_07 12:41 h1iscey
2014_10_07 12:41 h1odcy
2014_10_07 12:41 h1pemey
2014_10_07 12:45 h1iopiscex
2014_10_07 12:47 h1calex
2014_10_07 12:47 h1iscex
2014_10_07 12:47 h1odcx
2014_10_07 12:47 h1pemex
2014_10_07 12:48 h1broadcast0
2014_10_07 12:48 h1dc0
2014_10_07 12:48 h1fw0
2014_10_07 12:48 h1fw1
2014_10_07 12:48 h1nds0
2014_10_07 12:48 h1nds1
2014_10_07 13:04 h1pemex
2014_10_07 13:06 h1pemey
2014_10_07 13:08 h1dc0
2014_10_07 13:08 h1fw0
2014_10_07 13:08 h1fw1
2014_10_07 13:08 h1nds0
2014_10_07 13:08 h1nds1
2014_10_07 13:12 h1broadcast0
2014_10_07 14:56 h1calex
2014_10_07 14:56 h1iopiscex
2014_10_07 14:56 h1iscex
2014_10_07 14:56 h1odcx
2014_10_07 14:56 h1pemex
2014_10_07 15:02 h1iopsusex
2014_10_07 15:02 h1susetmx
2014_10_07 15:02 h1sustmsx
2014_10_07 15:06 h1hpietmx
2014_10_07 15:06 h1iopseiex
2014_10_07 15:06 h1isietmx
2014_10_07 15:35 h1calex
2014_10_07 15:35 h1iopiscex
2014_10_07 15:35 h1iscex
2014_10_07 15:35 h1odcx
2014_10_07 15:35 h1pemex

No unexpected restarts. A busy maintenance day. Daniel's ASC and ISC model changes. Addition of CAL models to end station ISC. Recovery of EX SEI and SUS after accidental crash. Associated DAQ restarts.

Sheila, Kiwamu,

Our focus tonight were:

• DRMI 3f lock
• DRMI WFS loops

(DRMI 3fs are now stable)

We succeeded in transitioning to the 3f signals in DRMI. We checked the demodulation phase of  REFLAIR_RF135 by exciting SRM and BS at a time. A good demod phase was found to be 56 deg while it had been -2.7 deg since the last week (see alog 14268). This demod phase was the one in which the SRCL signal is minimized in 135_Q. The resultant input elements are:

• RF27_I => PRCL = 1.0
• 135_Q => MICH = 0.7
• 135_I => SRCL = 0.3

I have not measured the open loop transfer functions yet, but so far I did not see a gain peaking. The SRM M2 stage coil output had an rms counts of about 1x10⁴ which is very OK in terms of the DAC saturation. I did not get a chance to see its long term stability. The ISC_DRMI guardian is edited accordingly and we confirmed that the guardian could transition to the 3fs automatically. Note that I enabled two whitening stages in REFLAIR_RF135. This saturates the ADC until the DRMI is locked, but once it is locked, the saturation does not seem to happen any more.

(some attempts on ASC loops)

For some reason, the SRCL mode-hop happened frequently tonight, even though the alignment was not too bad -- both PRC and SRC sideband power could fluctuate as small as a few % depending on misalignment which of course evolves on a time scale of order of 10 sec. So we decided to close the ASC loops rather than manually aligning the optics. We started from MICH which is ongoing.

There is a huge peak at 60 Hz in the damping singals on M0 of the SRM suspension. Also the noise floor seems too high compared with PRM. This must be fixed.

Reloaded the iscex/ey and asc models to enable the new camera channels.

The attached snap shows

• The script which copies the channels from the camera epics to the isc epics channels,
• The new medm with nominal and width fields to normalize the camera position, and
• The configuration file /ligo/cds/lho/h1/camera/H1-VID-CAM24.ini.

When the Y-arm is locked on green this should now give an error signal to the green alignment system.

J. Kissel

Following a similar procedure as was done for the ITMs (see LHO aLOG 14265), I've refined the calibration for the H1 SUS BS optical lever. The new calibrations are
BS P 6.9522 [ct/urad]
BS Y 3.8899 [ct/urad]

They've not yet been installed; will install tomorrow during maintenance.

DETAILS
------------
Currently, the alignment slider calibration gains are 
4.714 [ct/"urad"]
4.268 [ct/"urad"]
based on dead-reckoned knowledge of the actuation chain (see LLO aLOG 5362).

Sheila and Alexa recently found the alignment values for the beam splitter which gets red light onto the ETMY baffle PDs:
            P ["urad"]    Y ["urad"]
ETMY PD1      184.0        -255.0
ETMY PD4      237.1        -287.7
or a displacement of 
BS P    53.12 * 2 = 106.2 ["urad"]
BS Y    23.70 * 2 =  65.4 ["urad"]
where the factor of two comes from the single bounce optical lever effect.

I spoke with Gerardo who informed me that the numbers Keita had posted (LHO aLOG 9087) for the locations of the baffle PDs on the Arm Cavity Baffles are slightly off from reality. He gave me links to D1200296 (ETM) and D1200313 (ITM), which indicate that the PD locations are identical between an ITM and ETM baffle, and are 11.329 [inches] = 0.288 [m] apart in vertical, and 11.313 [inches] = 0.287 [m] apart in horizontal. Again using 3994.5 [m] for the length of the arm (LHO aLOG 11611), and adding 4.847+0.100+0.020+0.200 = 5.167 [m] for the distance between the HR surface of the BS and the back of the CP, through the thin CP, through the ITM QUAD's reaction-to-main chain gap, and through to the HR surface of ITM, respectively (D0901920), that's a lever arm of 3999.7 [m]. Hence, a displacement of
BS P   0.288 [m] / 3999.7 [m] = 72.01 [urad]
BS Y   0.287 [m] / 3999.7 [m] = 71.76 [urad]

The alignment offset slider gains should therefore be corrected by 
BS P  72.01 / 106.2 = 0.67806 [urad/"urad"]
BS Y  71.76 / 65.4  = 1.0972  [urad/"urad"]
or
BS P  1.4748 ["urad"/urad]
BS Y  0.91141 ["urad"/urad]

The new slider gains should therefore be
BS P    4.714 [ct/"urad"] * 1.4748 ["urad"/urad] = 6.9522 [ct/urad]
BS Y    4.268 [ct/"urad"] * 0.9114 ["urad"/urad] = 3.8899 [ct/urad]

We're now storing 4 alignments for the BS, 
                      P ["urad"]       Y  ["urad"]
BS Aligned              210.6             -271.4
   Misaligned           236.5             -287
   To EY ACB PD1        184               -255
   To EY ACB PD4        237.1             -287.7

which should therefore become,

                         P [urad]     Y [urad]
BS Aligned                142.8        -297.3
   Misaligned             160.3        -314.9
   To EY ACB PD1          124.76        160.77
   To EY ACB PD2          160.7         315.66

To do:
- Update calibration in OPTICALIGN gain
- Update calibration in M1 LOCK bank
- Update, confirm, and save corrected alignments
- Capture new safe.snap

J. Kissel

Following the refinement of the ITM alignment slider calibration (see LHO aLOG 14265), I used the sliders as a reference to refine the calibration of the optical levers. As suspected (see LHO aLOG 12216), the correction factor to the ITMX calibration is around a factor of two. The following new calibrations have been installed as of Oct 06 2014 19:00:00 UTC (12:00:00 PDT, GPS 1096657216):
IX P = 30.87 [urad/ct]
IX Y = 25.29 [urad/ct]
IY P = 23.94 [urad/ct]
IY Y = 24.01 [urad/ct]

I still need to capture new safe.snaps for both these suspensions to make sure both the refined slider and optical lever calibrations stick.

The process:
- Step through several alignment offset values (in [urad]), record DC optical lever output (in ["urad"], the quotes indicating the to-be-refined units). I chose to get a smattering of offsets between +/- 20 [urad] surrounding the currently saved "ALIGNED" values.
- Fit slope of data points to a line (see attached). The calibration corrections are
       ["urad"/urad]    [urad/"urad"]
IX P       1.578           0.6339
IX Y       2.233           0.4478
IY P       0.9767          1.024
IY Y       1.031           0.9703
- Correct calibration.

Previous Cal        * Correction           = New Cal
48.6954 ["urad"/ct] * 0.6339 [urad/"urad"] = 30.87 [urad/ct]
56.4889 ["urad"/ct] * 0.4478 [urad/"urad"] = 25.29 [urad/ct]
23.38 ["urad"/ct] * 1.024 [urad/"urad"] = 23.94 [urad/ct]
24.74 ["urad"/ct] * 0.9703 [urad/"urad"] = 24.01 [urad/ct]

I and Dan replaced the bad UL BOSEM unit (SN of bobbin part of that assy is SN250, D0601106-C) with a good one (SN282) pulled out of spare "half-assembled" tip-tilt assy (base plate SN 034).

We also replaced UR one (SN258) with a spare (SN134) that was pulled out of the same half-assembled TT assy simply because we were not sure if the open voltage of SN258 (about 20000 counts) was too small. Later it turns out that 20k counts open voltage is not abnormal.

The newly installed units were of course assembled in the past but without fit check, and it turns out that the gap around the connector was non-existent and I had to loosen some screws and shift things around to make a good gap. I also used aluminum foil shim trick.

After this, we centered BOSEMs for all Tip-tilts to half the open voltage.

WFS DC, AS_C QPD, OMCR QPDs, OMC QPDs and OMC DCPDs all responded to flash light.

Beam diverters moved back and forth.

Picomotors moved. On cable #234, the first, the second and the third channels correspond to WFSA, WFSB and AS_C picomotors. On cable #235, the first channel is the downstream 2" mirror for the QPD sled, the second the upstream 1" steering.

Checked ground loops from outside the chamber, and all cables including SUS were good except beam diverters (we know that they ground inside the chamber) and OMC QPDs (shield grounted to the DCPD signal ground) and OMC PZTs (same as OMC QPDs).