Attached are plots of dust counts > .5 microns in particles per cubic foot.
I and Daniel measured the WFS sensing matrix by a very slow (0.1Hz) excitation. This is because POS signal is much smaller (it's naturally smaller for a given mirror angle, and WFS placement is unfortunately such that both WFSA and WFSB are more sensitive to ANG).
Originally before the beam path change, I think Bram and Arberto measured the sensing matrix by giving a large offset to either ANG or POS. I also briefly tried this, but in order to have anything for POS, the offset needed to be so huge that the beam almost comes inside one segment, so I decided that this is not a good method.
Anyway, at 0.1Hz I was able to have a very good coherence for both PIT and YAW, POS and ANG. (Data file is /ligo/home/controls/keita.kawabe/OAT_2012/WFS_sens_20120831.xml)
Sensing matrix for PIT was OK:
WFSA = -0.313*POS -5.056*ANG
WFSB = +0.620*POS - 3.930*ANG
Sensing matrix for YAW was hopeless:
WFSA = +0.139*POS + 2.754*ANG
WFSB=+0.091*POS + 3.751*ANG
Thing is, for YAW, the sign of POS signal for WFSA and WFSB are the same, and in order to subtract large ANG signal we also need to subtract a large portion of POS, making the POS signal even smaller.
We think that the problem is that the beam parameters on the table is different from what was assumed when designing the Gouy telescope. We might try something on Tuesday.
In the mean time, I inverted the sensing matrix and put them in the input matrix:
PIT = [-0.9004, 1.1580; -0.1420, -0.0717]
YAW = [14.5307, -11.2063; -0.3703, 0.5656]
We turned PIT on and it seems to be doing fine. Didn't bother to do YAW.
Checking the beam path for WFS2 we noticed that the beam is fairly astigmatic. This beam path employs a converging lens which produces a focus ahead of a second diverging lens in order to pick up Gouy phase. There is a clear focus vertically. However, it appears that the horizontal focus would be behind the second lens. The beam is also still too large on WFS2. The easiest solution would be to remove the second lens altogether and make sure there is a focus in the horizontal plane. The beam may be somewhat small, but WFS2 can be moved backwards to compensate.
(Keita K., Daniel S.) We changed the reflection path towards the wavefront sensors on the ALS table. Previously, they were picked up through the rejected return beam out of the Faraday isolator. Unfortunately, this Faraday isolator uses a wedged calcite as a polarizer which generates numerous ghost beams which were impossible to separate. Instead, we placed a 10% beamsplitter just before the first PZT mirror to pick-up a fraction of the return beam. We then duplicated the lens in the return path and steered the beam towards the wavefront sensor setup. The beam size on the two wavefront sensors was still too large, so we moved them as close to the last steering mirror as we could. Hopefully, this will yield a more reproducible sensing matrix.
This means that the injected beam power was reduced by 90%.
Everything in the Hartman sensor path including the REFL_B_PWR diode is receiving 90% smaller light.
Offset of the REFL_B_PWR was adjusted so that it becomes zero when the cavity was unlocked.
Faraday-rejected light see the 90% splitter twice, and PDH diode is the only thing that receives 0.9^2 = 81% smaller light.
Using the picomotors interferes with cavity locking and seems to introduce glitches which are clearly visible in the cavity power (see circled regions in the attachment).
[Alex, Cheryl, Deepak, Giacomo]
Yesterday morning we couldn't work to the suspensions due to drilling going on in the LVEA. We used the morning to debug the binary IO: now it is working properly and both the LP status and the Coil Output can be enabled and disabled from the front-end as expected.
In the afternoon we carried a large HxTS barrel from the staging building, changed the disposition of HAUX and cover all of them with the barrel, to ease the effect of air turbulence when taking transfer functions and PSDs. The suspensions were left covered and undamped (and no ECD)for the night. Note that we found the position of many of the OSEMs to be offset by couple hundreds um (or more), while they were initially set to be centered better (sometimes much better) than 100 um. Later investigation (this afternoon) suggested that this was due to a combination of:
- the table not being completely leveled (or flat), so that when you move the suspensions around the position of the optics slightly changes
- the frames being unevenly clamped (we only used 3 clamps yesterday as we didn't know where to find others...)
- the OSEM being not very well tightened, so some of them may have moved during handling of the cables and the suspensions to fit them under the barrel.
We also found that leaving the uninstalled ECD close to the base (instead of putting them further away) did not noticeably affect the position of the optic, as initially suspected (however, installing the ECD does change the pitch, as observed before).
Today we adjusted the pitch of all suspensions to 0+-0.5 mrad (assuming the table levelled to this precision, that we were unable to check) using an optical lever (actually IM4 should be adjusted to +4.1 mrad, but since all the suspensions will need to be balanced again once we put he ECD in, we didn't bother).
We centered the OSEMs (intial centering was well within +- 50 um, but after moving them around it degraded to a little better than +-80), cleaned the setup a bit, clamped the suspensions with 4 clamps each and left them under the barrel.
I took TF of Y, P and L (attached), applying small actuation offsets to make the OSEM work around the central position. The transfer functions show no sign of problems, although the peaks are not exactly all in the same place (as already observed at LLO and expected, as the HAUX design does not include any mechanism to fine tune the resonances' position).
At about 22:05 I left the suspensions quiet and with damping off for the night, so tomorrow we can retrieve data for PSDs.
Thomas V I measured the output voltage out of the RH drivers for both ITMY and ETMY for different values of input currents (ranging from 0 to 1 amp). Attached is a spreadsheet of my measurements. Analysis soon to come, along with calibration parameters.
Eric A. - feedthrough protection install on HAM chambers Thomas V. at End-Y Keita at End-Y man-lift work in LVEA. completed by 10:30am Bubba running crane in LVEA ~2:00pm QUAD L2-stage coil output filter modifications in the morning hours before noon.
Updates to the QUAD L2 coiloutf filter modules were installed today on both ITMy and ETMy. The previous filter files were modified via foton and saved to the usual directory. The files were committed to the "cds_user_apps" SVN locally under: '/opt/rtcds/userapps/release/sus/h2/filterfiles/H2SUS*TMY.txt'. The following is the excerpt from the "H2SUSITMY.txt" file where the L2_COILOUTF_* filters are coded. The changes were to the FMs 5,6, & 7 for all four coils on ITMY and ETMY. The filter coefficients for both user models were loaded via the GDS medm for each suspension. The attached pdf is a transfer function of the filter modules with the original and updated pole/zero pairs. OLD: # DESIGN ITMY_L2_COILOUTF_LL 5 zpk([13],[129.973],1,"n") # DESIGN ITMY_L2_COILOUTF_LL 6 zpk([1],[99.9877],1,"n") # DESIGN ITMY_L2_COILOUTF_LL 7 zpk([0.5;249.809],[5;19.9999],1,"n") NEW: # DESIGN ETMY_L2_COILOUTF_LL 5 zpk([12],[110],1,"n") # DESIGN ETMY_L2_COILOUTF_LL 6 zpk([1.35],[80.5],1,"n") # DESIGN ETMY_L2_COILOUTF_LL 7 zpk([0.5;250],[6;20],1,"n") ------------------------------------------------------------------------------------------------------- ################################################################################ ### ITMY_L2_COILOUTF_LL ### ################################################################################ # DESIGN ITMY_L2_COILOUTF_LL 0 zpk([129.973],[13],1,"n") # DESIGN ITMY_L2_COILOUTF_LL 1 zpk([99.9877],[1],1,"n") # DESIGN ITMY_L2_COILOUTF_LL 2 zpk([5;19.9999],[0.5;249.809],1,"n") # DESIGN ITMY_L2_COILOUTF_LL 5 zpk([12],[110],1,"n") # DESIGN ITMY_L2_COILOUTF_LL 6 zpk([1.35],[80.5],1,"n") # DESIGN ITMY_L2_COILOUTF_LL 7 zpk([0.5;250],[6;20],1,"n") ### ### ITMY_L2_COILOUTF_LL 0 21 1 0 0 SimAcqOffL2 0.1022381444281 -0.9950269485578308 0.0000000000000000 -0.9513581602053965 0.0000000000000000 ITMY_L2_COILOUTF_LL 1 21 1 0 0 SimAcqOnL2 0.01018979855460631 -0.9996165783185160 0.0000000000000000 -0.9623720057438665 0.0000000000000000 ITMY_L2_COILOUTF_LL 2 21 1 0 0 SimLPL2 1.198428225279573 -1.9083200482101859 0.9083375891754886 -1.9904437581736589 0.9904583948159983 ITMY_L2_COILOUTF_LL 5 21 1 0 0 AntiAcqOffL2 8.999262730598492 -0.9586809127066087 0.0000000000000000 -0.9954086141798147 0.0000000000000000 ITMY_L2_COILOUTF_LL 6 21 1 0 0 AntiAcqOnL2 58.74299131244113 -0.9695955355155262 0.0000000000000000 -0.9994824154540793 0.0000000000000000 ITMY_L2_COILOUTF_LL 7 21 1 0 0 AntiLPL2 1.000393883340034 -1.9900610320883918 0.9900785927850526 -1.9082531975983987 0.9082707513809170
Greg, Jim, Hugo,
We huddle tested the GS13s intended to retro-fit eLIGO HAM6-ISI. Test results are attached.
(corey, greg, jim, justin, mitchell)
This morning we boxed up HAMISI#7 (destined for HAM#4). This took about 2-2.5hrs.
Eric J, Thomas V, Apollo The holes to set pylons and giraffes are drilled on the input side of H1, this includes the HAM2 and HAM3 optical lever transceivers as well as the PR3 transmitter and receiver(giraffe). We also set the dwarf pylons down on the anchor bolts and are currently looking to have viewports placed in before installing more delicate components. The H1 output side is being laid out and drilled today as well.
Mag 7.6 earthquake (or an aftershock) in the Phillipines tripped the BSC8 HEPI & ISI and BSC6 HEPI.
Unit 3 HAM had its cabling and pods removed on the 28th and was resealed in a storage container. A purge was started shortly thereafter. Interestingly the time it took to drop below -25 td°C was very similar to Unit 6 which had cabling and viton.
Attached are plots of dust counts > .5 microns in particles per cubic foot.
About 50% of the H2 front ends were upgraded to RCG 2.5.1 last week, this week I cleanly rebuilt and restarted all H2 frontends against 2.5.1 in conjuction with the timing change.
All of H2's timing signals were moved from the old h2 timing master to the new h1 timing master. The old h2 timing master is being decommissioned.
errors in the burt restore of the safe.snap files were seen on h2peml0, h2tcsitmy and h2pemey (my problem, I'll fix these).
Problems with a large ADC input on h2hpietmy is being tracked to a HEPI pump issue at EY.
The 24MHz RF amplifier at EY is showing a timing problem on the fanout, and its fpga led is blinking red sometimes.
Fixed timing synchronization of the EY RF source by power cycling the unit.
We measured the transfer functions to the cavity length from M0 POS, L1 POS and L2 POS, when the cavity was locked and only M0 was damped.
At the same time we also measured the transfer functions from the same actuation points to the OPLEV signals.
Two main goals of this were:
1. To see if L2 stage (penultimate mass) drive was working fine. There has been speculations but no definitive answer.
2. To provide a set of measured data for SUS so hierarchical control effort could be accelerated.
Anyway, if you're only interested in the plots see attached. Frequency points are kind of sparse and not even (the former is constrained by time, the latter is by the fact that I'm throwing away low coherence data).
Plots as well as data files etc. are all under /ligo/home/controls/keita.kawabe/OAT_2012/ETM_M0_L1_and_L2_POS_to_L3
Everything was checked into svn: /ligo/svncommon/SusSVN/sus/trunk/QUAD/H2/ETMY/Common/Data/2012-08-27_H2SUSETMY_M0_L1_L2_POS_to_L3
[Update 13:30-ish 28/Aug/2012]
The plots are now normalized by the L2L element of the drivealign matrix, as that was 1 for M0 and L2 (as it should be) but 10 for L1 for whatever reason.
Two things that are obvious from the plots:
(Updated 13:30-ish Pacific, 28/Aug/2012) 1. L2 drive is working. It is about a factor of 120 or so weaker than L1, and L1 is about a factor of 6 weaker than M0 (see page 1).
1. L2 drive is working. It is about a factor of 12 or so weaker than L1, and L1 is about a factor of 60 weaker than M0 (see page 1).
2. Cavity length to angle coupling could be problematic at resonances (see page 4). At DC for M0, it seems to be 0.1rad/m in a ball park, and and even if we feed back 1um RMS this is 0.1urad RMS, which sounds OK.
One thing that is not obvious from the plot:
For L2 drive, I had to use a ridiculously large excitation (+-120000 counts, half about a quarter of the range of 18bit DAC considering the output matrix of 0.25) with ridiculously long integration time (e.g. 160 seconds) to get a good coherence for f>1Hz. The background noise is too large.
This practically means that, as others pointed out, L2 is going to be railing if the ALS signal is fed back to L2 with a UGF of 1 Hz.
0.1Hz might be possible, but 1Hz, not likely.
Other things:
When the measurement was done, L2 stage driver FM2/3/5/6/7 were on while FM1 was off.
EUL2OSEM output matrix elements for M0 (for two lower face coils F2 and F3) were (0.5, 0.5).
EUL2OSEM output matrix elements for L1 and L2 (for all four coils) were both 0.25*(1, 1, 1, 1).
Update Aug/31/2012
In the above entry,
"When the measurement was done, L2 stage driver FM2/3/5/6/7 were on while FM1 was off."
this was incorrect but I cannot edit it any more, it seems. It should read
" L2 stage driver FM2/3/6/7/8 were on while FM1 was off."
J. Kissel, B. Shapiro I attached plots comparing Keita's transfer functions to what I expect from the model. Executive summary: 5 of the 9 transfer functions measured match my model exquisitely -- All L to L TFs, and the TOP to TST, and PUM to TST L to P TFs. Of the remaining TFs: I don't expect the model to predict the L to Y coupling well at all, but I'm still baffled as to why the UIM to TST L to P transfer function doesn't match up. Comments / questions / concerns welcome. I really haven't yet been able to get a warm and fuzzy feeling about a lot of this data. So, take it with a grain of salt. You'll notice that among the series of plots is the predicted maximum range for each stage. Please don't read too much into these numbers, I haven't yet verified them against Norna's numbers (see T1100595), taking into to account the differences between her numbers and mine (mostly the maximum range of the coil driver, updated to use the real, recently measured, transconductance of the coil drivers times the 10 [V] DAC range.) BUT I know that frequency response is accurate, because it uses the latest and greatest measured responses. Notes / Details: - There are fudge factors that I don't yet understand. They're explicitly called out in the legend, but they're summarized here: %L P Y driveAlignGain = [-1 -1 -1;... % M0 -5 -5 -5;... % L1 1 1 1]; % L2 meas(iStage,iDOF).tf = meas(iStage,iDOF).tf / driveAlignGain(iStage,iDOF); As Keita mentions, I expect the L1/UIM fudge factor to be 10 not 5, from the driveAlign gain. I'm NOT really that surprised that we got the sign wrong on M0 and L1, but I don't know yet where it lies. - The modeled M0-only damping loops are not *exactly* representative of what Matt tuned a month or 3 ago, but they should be close enough. I expect the overall gain to be different, and I expect the low frequency bump filters to be different, but otherwise they should match pretty well.
