Ed and Kiwamu,

In the morning of today and yesterday, we went through all the initial aligment steps. In the course of the process, we found that there were a few settings that were hidden and not set correctly. So we made a couplle of modifications on the guardians and filter in order to automate them:

• edited LSC_CONFIGS such that it takes out the 160 dB attenuators (alog 16315) out of ASAIR_RF45 in the LOCKING_X(Y)ARM_IR states.
• edited LSC_CONFIGS such that it sets the whitening gain of REFL_A_RF9 back to 0 dB.
• added a new filter in LSC-ASAIR_A_RF45 in order to compensate the 20 dB attenuation (alog 16334).
• also, added another new filter in LSC-ASAIR_A_RF45 which gives another 20 dB. This got rid of the gain factor of 10.

The attached screenshot shows the current good settings in order to go through the alignment sequence. This configuration should be automatically achieved by the guardians.

Kiwamu, Elli, Alexa, Evan, Rana, Daniel, Sheila

Today we were able to reach CARM offsets around 30 pm.  

We transitioned DARM to AS45Q, at a CARM offset where sqrt(TRX+TRY) was -7, we then normalized the signal by sqrt(TRX) (with a factor of 0.23).  One important step in getting there was to implement the ezca servo that adjusts the ALS DIFF offset to bring AS45Q into the linear range.  We are now using that both at a CARM offset of 1 (in SQRT TRX+TRY), and after we transition to the QPDs.  We then change the DARM loww pass filter from a 33Hz low pass to a 80 Hz low pass, to get better phase margin since we are no longer saturating the ESD with ALS noise.  We did this transition several times sucessfully.  As Rana mentioned in alog 16334, we installed an ND1 filter on ASAIR A.  Since this we haven't transitioned to RF DARM again (for reasons that seem to be unrelated to the ND filter), so we will need to check the gain before we transition again. 

After making this transition, Elli, Kiwamu and Rana worked on the DHARD WFS, which we turned on to reduce the fuctuations in AS DC.  This allowed us to go to CARM offsets -25 in sqrt(TRX+TRY), which is about half of the total power we expect in the arms.  If you assume that the recyling gain is 30 (we don't really know) it is something like 30 pm.  In Refl DC we saw the power drop by about 20%.  We saw that the linearized REFL 9 I signal had turned over, and that without linearization the signal had reached the peak.  We made a few attempts to transition, and we were able to turn down the gain of the TR CARM signal to 50% of the nominal and turn the REFL 9 signal to what we think the nominal gain should be (-100 in the input matrix).  We lost the lock when we turned off the TR CARM signal.  Our next plan was to leave the TR CARM engaged with reduced gain, and keep reducing the CARM offset.  

However, we have been having a hard time locking in the last few hours.  We think that it might help to try transitioning to DARM to RF a little sooner, so that we could use WFS.  

The sequence that was working earlier this afternoon is in guardian up to the RF DARM transition, although this might need to be re-worked.  We have added but not tested a state for the DHARD WFS. 

Attached is a screenshot of our striptool durring the sequence, which was all handled by the guardian this time.  

Alexa, Rana, Ellie

We noticed that one of our locklosses during the CARM offset reduction (after we're transitioned onto AS45 -> DARM) seems to be due to ADC sauration in ASAIR 45 so we put in an ND1.0 screwed onto ASAIR_A.

In the attached plot you see that ASAIR_A_45 goes to 0.0003. Since we have a -160 dB digital filter between the ADC and this point, this corresponds to ~32000 counts at the ADC.

OTOH, REFL9 seems to be pretty puny (~500 counts with half of the full buildup), so we're turning up the gain on there by ~10 and turning on the Whitening filter to see if it helps the CARM noise be low.

To get bigger plots in dataviewer (i.e. getting the plot window to auto-scale) for both playback and 'real-time' plots, you can now just set up an option in your GRACE environment:

1) In your user directory make a directory called .grace:      mkdir .grace

2) Change to that directory:                                   cd .grace

3) Copy my gracerc file into your directory:                   cp /ligo/home/rana.adhikari/.grace/gracerc.user .

Now, when you restart dataviewer, you will have autoscaling.

BTW, this is described somewhat in CDS Bugzilla #377 from Tobin Fricke, Jim Batch, & Keith Thorne.

Completed the BSC file modifications today like the HAM-ISI yesterday and HEPIs last Thursday.  Now all SEIs are monitored by SDF with Guardian doing the rest.  There remain red issues (5 platforms) I did not clear to remind us of ongoing questions & issues to address.

Summary:

QE and transimpedance combined for Baffle PD1 and PD4 on all ITMs and ETMs agree with each other within 10%. In the table below, QE/transimpedance combined for each PD is normalized such that the average of all diodes becomes 1.

I haven't done any error analysis, but the biggest error should be the systematic in ITM-ETM comparison that was introduced by an assumption that IR mode matching is perfect.

PD1-PD4 comparison on the same baffle (e.g. ETMX PD1 and PD4) should be quite good.

Details:

This is yet another baffle health check.

The other day I used some short time available to misalign TMS and steer MMT3 to point IR beam on ETM baffle PD4, first on  ETMX and then on ETMY. This could be used to make ETMX(PD4)/ETMY(PD4) comparison, assuming that the IR straight shot beam size is the same on ETMX and ETMY.

Then I proceeded to align MMT3, align ETMs to point the beam to PD4 on ITM baffles. Since ETM reflectivity is basically 1, and since the mode matching cannot be as bad as green, we can use these measurements combined with nominal IR beam size to make ETM(PD4)/ITM(PD4) comparison.

Also, when people do initial alignment they are basically doing PD1/PD4 comparison on a single baffle using green beam. (You cannot make comparison across different baffles using green because of the beam size difference described in my previous alog.)

So, stitching all these together, if we believe that the QE variation of diodes for green is the same as that for IR, we can map out the QE/transimpedance combined for all baffle diodes.

In the table below of the raw data, photo current in mA for straight shot measurements of green on PD1 and PD4 as well as IR on PD4 on all arm cavity baffles are shown.

Green data can be used to make PD1/PD4 ratio on each of the optics.

IR ETM data is used to make PD4 ETMX/ETMY ratio.

IR ITM data, combined with the nominal IR beam radius on ITM and ETM (53.4 and 63.5 mm, respectively), is used to make PD4 ETMX/ITMX and ETMY/ITMY ratio.

After some math we get the table at the top of this entry.

06:45 Karen into the LVEA

07:00 Cris into the LVEA

08:00 set OIB to 'Commissioning'

08:05 unlocked DRMI to start practicing locking Green light to arms (ALS) No luck. Later learned the proper way to unlock DRMI. Thanks Kiwamu

08:30 Morning meeting

08:45 Started working with Kiwamu on getting my first arm locks. SUCCESS!

09:09 Betsy and Mitch to W bay

09:22 Jeff B to LVEA

09:29 Mike L into LVEA

09:30 Jeff B out of LVEA

09:49 Mike L out of LVEA

09:52 McCarthy to EX

10:54 Betsy and MItch out of LVEA

10:55 Caterers on site

11:03 McCarthy back from EX

11:07 Fil to MY

11:43 Fill back from MY

12:15 Vanessa to MY

12:24 S&K Electricians to EY

The temporary barrier originally installed for the DCS construction has been removed. Mechanical is 98% complete with remaining items being plenum grills and dampers, start up of the HVAC system by a factory rep, installation of cable trays and some touch up painting. Electrical is on the order of 70% complete. 

Like the quad model scripts (LHO 16126), I updated the generate_Triple_Model_Production.m and generate_Double_Model_Production.m functions so that you can specify a foton filter for the top mass damping loops.

The generate scripts is in

.../SusSVN/sus/trunk/Common/MatlabTools/TripleModel_Production

and

.../SusSVN/sus/trunk/Common/MatlabTools/TripleModel_Production

If youhaven't done so in the past week, you will also need to svn up

.../SusSVN/sus/trunk/Common/MatlabTools

since this is where the foton file reading functions are located (imported from the SeiSVN)

You can still specify the usual .mat struct file as before. The generate script looks for the .txt extension to determine if you are sending it a foton file.

Here is an example of how to make a model with damping filters read from foton:

hsts_model = generate_Triple_Model_Production(frequency_vector_for_plots, 'hstsopt_metal', [], 0, 1, '/opt/rtcds/lho/h1/chans/H1SUSMC1.txt')

IMPORTANT: The foton file does not know which filter modules are engaged. This information is coded into the function with a variable called medm_engaged_modules, which must be updated at the time of running the script. The script will output to the command line which modules are being used for each filter, and where to change in case you forget. For a variety of reasons I thought it more convenient from a user-point-of-view to have this coded into the function rather than as another input to the function, however this could be modified. This is the same in the quad script.

These functions have more instructions commented into their headers.

Just have the single sus scripts to go.

Summary:

Green straight shot beam size on ITMX is a factor of 0.87 of nominal (i.e. too small) while ITMY a factor of 1.2 too large.

The beam radius ratio is (X/Y)=0.72, which makes the ITMX baffle PD output current to be a factor of 2 larger than that of Y when you hit these PDs using a straight shot beam.

There used to be a factor of 2 to 2.5 unexplained difference between the photocurrent in ITMX and ITMY baffle diodes during initial green alignment, but the beam size explains a factor of 2, so the remaining factor is about 1.2 or so, which I don't care for now.

Background:

This is one of those health check type stuff. Baffle PDs could be used for scattering measurement but the health of some of those PDs were in question.

One of the suspicions came from the fact that, when looking at green straight shot beam during full initial alignment, PD current from X arm baffle is much larger than Y arm. A part of it comes from the laser power (there's about a factor of 2 or so difference) but the baffle PD current is a factor of 4 to 5-ish different, so there always was a factor of 2 to 2.5 unexplained.

Details:

I first used dither align script to point the TMS beam to PD1 and then PD4 of the ITM baffle. Since the horizontal distance between PD1 and PD4 is 11.3", the script allows us to calibrate TMS alignment slider.

Immediately after the script finished, I pointed the beam to PD4 center, move TMS in YAW in one direction by more than the beam radius,  and ran another script to move TMS in YAW, wait and measure PD4 current.

Attached is the YAW scan data (circles and crosses) as well as the fit to Gaussian profile assuming the same radius in PIT and YAW:

current = ofst+ A * 2/pi/w^2 * exp(-2*(X-X0)^2/w^2)

where w is the beam radius and A is an overall factor.

The last column in the above table shows QPDA_SUM+QPDB_SUM. If everything makes sense, and if the beam was at the same height as the PD center during the scan, QPD_SUM ratio should agree with A ratio, but apparently it doesn't at 20%-ish level. This is good enough because the suspicion was that there was something grossly wrong about the baffle PDs.

BTW we can do the same thing for IR beam, scanning MMT3, to assess the IR matching to the arms if we want to (or better yet, do the spiral scan to see both PIT and YAW).

Looks like lock was from about 9:14 UTC to 16:09 UTC. For posterity.

http://earthquake.usgs.gov/earthquakes/eventpage/nc72387946

Ground velocity exceeds 20 μm/s from 0.03 Hz to 0.1 Hz. IMC MC2 transmission is noticeably wobbly.

Added 2 channels and removed 788.

Work Permit review.

SEI - continuing work on SDF system for BSC ISI. HEPI pump servo is ongoing tinvestigation. Maybe Jeff will run some TFs looking at 1Hz to 10Hz at some point today.

SUS - no big news. Thomas will ressurect the Drift Monitor this week sometime.

ISC/Commish - taking small steps in the positivedirection. Had a rather lengthy DRMI lock last night beginning ~01:30.

3IFO - no activities in LVEA. All activities across the street.

Facilities - Beam Tube cleaning is ongoing. Gutter work is don at LSB. Crew has moved to VPW.

CDS - variac installation at End station for Heater. Work in HAM6 area on Fast Shutter. R Abbott will be coming to work with this.

Gary will be moving ISS arrays and using the large airlock door in the LVEA

Sheila, Evan, Rana, Eli, Kiwamu, Alexa

Today we were able to reduce the CARM offset from 800pm to 100pm. We made three major changes to acheive such an offset.

1. We noticed that the sqrt(TRX+TRY) counts into the CM board was only about 100 pk-pk. We increased this to about 800pk-pk by reallocating some gain. We decreased the LSC-REFL_SERVO_IN1_GAIN from 0dB to -16dB, and increased the LSC-REFLBIAS_GAIN from 8 to 50.4.
2. We added a z20:p40 to REFLBIAS in order to get more phase and push the UGF of TR CARM from 200 Hz to 150 Hz. This filter is only engaged after we have already turned off ALS COMM, at which point we do not need to compensate for the COMM PLL VCO.
3.  We noticed that ASAIR_RF45_Q was rather noisy as we were reducing the CARM offset. We added an integrator FM2 (z2:p0) to ALS DIFF to reduce low frequency noise. This helped make TR CARM more stable.

Transition Process from 800 pm to 400pm

To start,

• LSC-TR_CARM FM1(2pm), FM9(z35:p1k^2) ON
• LSC-TR_CARM_OFFSET = -0.5
• LSC-REFLBIAS FM9 (z40:p1.6), FM3 (z40:p1) ON, GAIN 50.4
• LSC-REFL_SERVO_IN1 GAIN -16dB
• ALS-C_REFL_DC_BIAS GAIN 28
• TRAMPs at ~13 s

With some TR buildup (approximately 1ct on LSC-X/Y_TR_A_LF_OUT),

• LSC-REFLBIAS FM6 (z1:p0), FM4(z1:p40) ON, GAIN 28.0
• Ramp down LSC-REFL_SERVO_IN2 Gain from 16dB to -32dB then turn off ALS-COMM

With CARM on sqrt(TRX+TRY),

• LSC-REFLBIAS FM10(z20:p40) ON, GAIN 28 at -0.5 cts offset (Note: the gaurdian does up to this point)
• LSC-REFLBIAS GAIN 39 at -1.0 cts offset

Transition Process from 400pm to 100pm

With all the settings as above, we bring the CARM offset to -3.2 (or ~150pm). At this point we transitioned the in-air TR PDs to the IR TR QPD_Bs.  For reference, ASC-X/Y_TR_B_POW_NORM =1,1  and LSC-TR_X/Y_QPD_B_SUM_GAIN = 0.222, 0.175 respectively. Also, the QPD NSUM was about 400cts here. We continued to reduce the CARM offset to -4.5 cts (or ~80pm). At first,t the ASAIR_RF45_Q looked like a decent signal and responded well to a DIFF offset change. We turned on a servo for about 1.5min to ensure ASAIR was around zero (z servo -r LSC-ASAIR_A_RF45_Q_NORM_MON -g -11111 ALS-C_DIFF_PLL_CTRL_OFFSET).  We measured ASAIR_RF45_Q/DARM_IN1 = 3e7 (at this point DARM_IN1 is just ALS DIFF signal). Note: we added a -160dB FM10 filter in LSC-ASAIR_A_RF45. Then the PD_DOF_MATRIX for ASAIR_RF45_Q is 3.3. So far, we were able to transition from ALS DIFF to RF DARM 50% of the way, and then we broke the lock. We started to reconsider whether we were actually in the linear range for RF DARM. Maybe we should be using AS45Q/SQRT(TRX) at this point? This requires a model change; however, this is already impleneted in the l1lsc.mdl that is in the SVN, so we could just copy that.

A little more ...

The farthest CARM offset we reached was -7 cts or ~60pm on sqrt(TRX+TRY) with the QPDs controlling CARM and ALS DIFF for DARM. Here we had 26 x single arm power, and REFL DC dropped from 80mW to ~75mW.

The stopband filter we put in the ETMX OL servo yesterday seems to have done the job of preventing the ringups:

In the attached trend of the OLPIT 3-10 Hz BLRMS, you can see the ringup start around 6AM local time this Sunday, the 25th.

Around noon on Monday (1800 UTC), Evan and Alexa start damping the mode using the bandpass filter in the OL PIT servo. They stop around 2100 UTC when the mode is small. It then rings up for the next 7 hours until we turn the stopband filter on.

Then it rings down with a 1/e time of ~4 hours (which implies a bounce mode Q of ~440,000 if nothing else is driving it).

We should make sure to install these on all of the test mass OL servos.