As part as Tuesday maintenance today March 8, 2016 CDS system admins will be deploying a new file system ( /Ligo ) the switch over will limit the ability to use any workstation or server that mounts /Ligo until the work is completed; Once the switch over on the MSR has been done, every workstation must be updated and restarted.

Sheila, Jenne, Matt, Rob, Evan, Lisa

Several things happened today, more details will be posted later:
we locked several times in low noise (note: ASC in the old configuration with DC (not RF90MHz) centering, see week-end entries for more details): the best range we saw today was about ~70 Mpc, due to some peaks in the spectrum higher than usual -- the 290 Hz was particularly higher than during O1;
in low noise Sheila made several ISI shaking tests, Robert did some investigations in parallel as well;
we looked at the coupling into the OMC at full power: this measurement needs to be repeated to make sure the conclusion we get is right, as the inferred coupling to the OMC would be significantly lower than what assumed from previous measurements;
Jenne took some DHARD open loop transfer functions as function of the DARM offset;
some off-line investigations to get hints of the mystery noise happened as well, more details will follow.
 
Some of these things are not finished as an earthquake hit us around 10pm local time; we waited for two hours for the noise to go down again, but we couldn't really relock robustly afterwards, even when the ground motion seemed back to normal (to be investigated). 

Some items for our to-do-list that came up tonight (to be merged with what we already have on the control room whiteboard) are:
inspired by Kiwamu's analysis, modulate the vertical position of optics and look for changes in the DARM noise;
(new entry): look at the DARM rms, and see if there is some loop optimization that can be done to minimize it (in particular, check if rms optimization advocated by Jeff at the last commissioning workshop happened or not);
in-depth analysis of frequency noise, in particular look for saturations in the common mode board;
close the loop on this OMC coupling, and if it is real, distinguish between mode mismatch vs misalignment - if it turns out that the alignment into the OMC is bad, resurrect deacon alignment (ECR already submitted and approved).

Lisa, Evan

We repeated the DARM-to-OMC coupling test (25852) at full power.

Tentatively, the change in the violin mode heights with the OMC locked and unlocked suggests only a 75 % coupling into the OMC (i.e., a 25 % loss).

We are not sure why the violin mode at 502.8 Hz is fatter with the OMC locked, so we would like to repeat this test with a calibration line.

I made a quick "noise budget" which accounts for most of the H1 noise with just shot noise, coating thermal noise, a 1/f mystery noise, and a 1/f^4 "other noises" curve.  This is a much poorer version of the real noise budget, but it is enough to help with the mystery noise search.

State of H1: locking well, and made it to Low Noise multiple times

Commissioning:

• noise hunting

Site activities:

• Gerardo to CP3

Current Status:

• waiting out an earthquake, which arrived around 6:05UTC
• Commissioners here - planning to relock and continue working

Even if H1 had been brought back to low noise before the week-end, the SensMon was not properly showing the range. This was due to a change in the whitening filters in CAL_DELTAL_EXTERNAL_DQ that happened last week (see  Sheila's entry ). John Z updated SensMon to take the new filters into account (thanks John), so the range monitor is back, and the summary pages show it correctly. 

WP 5765  See T1600062 for details of all updates.

SVN UP'd:

hugh.radkins@operator3:models 0$ svn up
U    isi2stagemaster.mdl
A    ISI_to_SUS_library.mdl
Updated to revision 12797.
hugh.radkins@operator3:models 0$ pwd
/opt/rtcds/userapps/release/isi/common/models
 

hugh.radkins@operator3:src 0$ pwd
/opt/rtcds/userapps/release/isi/common/src
hugh.radkins@operator3:src 0$ svn up
A    WD_SATCOUNT_vb.c
Updated to revision 12797.

Top Level Model edits:

Added Paths to all BSC top level models to calculate the SUSPOINT motion in the ISI.  Once these are working in the ISI model, the calc done in the SUS model and the IPC to the SUS will be removed.  See the attached for a before (left) and after (right) look at the model changes.
 

This morning we had a combination of moderately high winds (gusts up tp 30-35 mph) and microseism above the 90% percentile, this is a combination of ground motion conditions where we had trouble durring O1.

We attempted to lock several times, and probably would have been able to if we had just kept trying, although we had random locklosses at diffrent stages of the CARM  offset reduction. 

One thing that we know is a weak point in our acquisition now is the ALS DIFF loop, so Matt and I had a look at improving that loop.  We saw that our UIM control filter, which has some modest plant inversion to make the crossover between the ESD and UIM stable, was not quite right.  We had features just above 2 Hz which were causing us to nearly have a second UGF there, and gain peaking was clearly visible in our control signals.  This was predicted by the sus model and our filters, although reality was a little worse than what was predicted.  

The first attached screnshot is the OLG before (blue) and after (red).  You can see that there was a small dip that nearly had multiple ugfs just above 2 Hz, which is improved a little.  THe second screenshot shows the crossover measured by injecting at L1, the third one shows the change to the filter. 

With this filter, we were no longer able to engage the 1 Hz resonant gain in the DARM filter bank.  From our model it isn't clear why that would be, but we also don't see any reason why we need such an aggressive ResG at the moment, so we are leaving it out.  

1/2 open LLCV bypass valve, and the exhaust bypass valve fully open.

Flow was noted after 95 seconds, closed LLCV valve, and 3 minutes later the exhaust bypass valve was closed.

Next over-fill on Thursday, March 9th before 23:59 utc.

It turned out that all my previous analysis did not correct for the time-varying optical gain when calibrating the cross spectra into displacement even though I thought I have done it. I have recalibrated all the O1 data with the optical gain properly corrected.

Fortunately, the conclusions I have arrived so far qualitatively did not change.

Related alogs: 25847, 25768

Here are some plots with the newly calibrated cross spectra, mainly to show there is no drastic changes.

Fig.1 Band limited rms of the cross spectra in time series for the entireO1 run. The old data (without the optical gain correction) are show as "+" symbols while the recalibrated data are shown as dots.

Fig.2 Ratio of the band limited rms, (new data) / (old data). Notice that the high frequency bands (bands 3-8) tend to have larger displacement now. The low frequencies do not fluctuate as big as those for high frequencies as expected.

Fig.3 A naive correlation diagram in which the linear dependency between high frequency bands (bands 5-8) is still visible.

Fig.4 Time series plot of scaled band 8 BLRMS, LVEA temperature and scaled vertical sensors of various suspended optics.

Laser Status:
SysStat is good
Front End power is 32.01W (should be around 30 W)
Frontend Watch is GREEN
HPO Watch is RED

PMC:
It has been locked 12.0 days, 22.0 hr 9.0 minutes (should be days/weeks)
Reflected power is 3.078Watts and PowerSum = 25.24Watts.

FSS:
It has been locked for 0.0 days 0.0 h and 15.0 min (should be days/weeks)
TPD[V] = 1.466V (min 0.9V)

ISS:
The diffracted power is around 8.465% (should be 5-9%)
Last saturation event was 0.0 days 0.0 hours and 15.0 minutes ago (should be days/weeks)

For further in-depth analysis of the trends, please refer to Jason O., Pete K. or Rick S.

FAMIS#4140  closed

I have power-cycled camera 18 and restarted it's server. It appears to be working again.  My first try at just restarting the server didn't work, only after power cycling the camera did it appear to be working.

After the removal of polarization sensors for ITMX HWS an adjusting HWS STEER M10 to center onto ITMX HWS, as reported in alog25718 , we performed CO2 and RH tests on the ITMX HWS. The results show that the ITMX HWS beam is aligned and working as expected.

CO2 Test:

         We performed the CO2 test on March 1, turning up the CO2 laser deliver power to 4W between 1140906458 and 1140908050. The spherical power behaves as expected (see image CO2_ITMX_1Mar_SP.png )

                             - The spherical power increases up until tthe CO2 is turned off with the maximum change in spherical power of about 60 microdiopters

                              -After CO2 laser is turned off, the spherical power can be seen to decrease slowly before the ITMX HWS is stopped streaming

           The gradient plot also shows this change in spherical power:

                             -All arrows are pointing inward towards the location where the CO2 beam is positioned on the test mass (see image CO2_ITMX_Gradient_1Mar.png) , which has an offset towards the +ve y-direction and -ve x-direction from the centre of the HWS beam. 

                             Since the CO2 laser beam alignment is optimized for interferometer beam, an offset is acceptable.

RH Test:

              We performed the RH test on March 6 to check for the alignment of the ITMX HWS beam on the test mass. The HWS ran between 1141342135 and 1141351367. Both upper and lower RH's on ITMX is turned on to 1W for two hours between 1141342544 and and 1141349746. The recored spherical power also behaved as expected (see image RH_ITMX_5Mar_SP.png):

                               -The spherical power starts decreasing slowly as the RH is turned on.

                               - After  RH run,  the maximum decrease in spherical power is approximately 70 microdiopters before starting to increase back to 0 again. The time scale between after RH is off and increase in spherical power is about 30 minutes.

               The gradient plot shopws the evidence of this change in spherical power. All arrows grow outwards from the center and distributions of dx and dy change are more or less uniform around 0 (no apparent skewness) , which also imply that the ITMX HWS beam is correctly aligned on the center of ITMX. (see image  RH_ITMX_Gradient_6Mar.png ).

For a long time we have not been offloading the green wfs from ETMY, because doing so would with the same code we use for END X would cause the optic to get a big kick.  This morning Jim and I gave this another try, and saw that the main difference between the test masses is that ETMY had some plant inversion from 1-10 Hz, when we turned this off we could offload ETMY without a problem. 

Apparently the current arrangement of ETM WFS used durring ALS locking needs these plant inversions to be on. 

Plotting the cross-correlated DARM noise (band 5) and LEVA temperature on the same plot doesn't show any obvious relationship.  The .fig is included in case someone has a good idea of how to use this data.