We leveled the optical path from the laser to the first MCL PZT mirror, but things didn't improve much.

The first Faraday transmission is fine (first picture, EOM and the second Faraday removed from the path, picture taken in front of the second lens).

EOM transmission is ugly when the beam passes through the middle of the input and output aperture (second picture).

After fiddling around with the EOM alignment using 4 DOF stage, we always ended up with the beam very high on the input side. (no picture).

After the EOM, when the second Faraday was inserted, it makes many ghost beams /halo  in PIT (third picture). This vertical pattern doesn't change much with alignment.

Using an iris, we can get rid of most of the ghost beams (last picture). The central part of the beam is not totally round, this comes from the EOM. This looks somewhat better than OAT days (sadly).

Anyway, since it is convenient to open up the iris to see the retro reflected beam from ETMY, we left all irises wide open.

The Faraday makes many ghost beams for the refl beam too, but all of these seem to fall on the PD.

We measured the power level right at the laser, downstream of the first Faraday, downstream of the EOM and downstream of the second Faraday. Jax will post the numbers.

With approval from Keita to proceed, Kiwamu got the Mode Cleaner locked and tuned up a bit.  We then moved the ISI-in-a-can to as close as possible to WHAM4.  It now sits north of HAM4, I say the center of the load is about 5m away from the center of the chamber.  We monitored the lock state of the IMC and it remained locked through the duration.  The load was lifted and started moving toward WHAM4 at 1456PDT(2156utc) and was set down at the above location at 2201utc.

Damping loops were turned on for the ISIs of the IMC to support locking effort.

The payload screen of the HAM-ISIs now feature links to the MEDM screens of the related suspensions. For example, one can now click on the MC1 button of the HAM2-ISI payload screen, and get re-directed to MC1's MEDM screen. This is especially useful if the suspension(s) tripped the ISI. One can then open the payload sceen, find out which suspension tripped the ISI, and un-trip it in a couple clicks.

Kyle has been pumping the Vertex volume for about 9 days now. The trend is attached. Note that about 1/2 of the annulus systems are under vacuum.  The plot shows the affect of pumping GV2 annulus. This indicates a leak in this annulus system - likely not a serious problem. As pump carts free up they will move to other annulus systems.

Lightpipes (i.e. "light hoses") were installed on ISCT1's (1)REFL/POP & (2)ALS (green) paths.  This completes all (3) light pipes for ISCT1.

The backup file server cdsfs1 required a reboot, it had become unresponsive. It was found that the tape backup machine had also lost connection with its SCSI library, so it was also rebooted which restored the connection.

Since we had not performed a disk-to-disk backup of cdsfs0 nor h1boot since yesterday evening, I did a manual rsync of these at noon. I then checked to see if the rsync of h1boot still causes front end epics slow down problems, and found that this problem is now not seen. So I have increased the frequency of h1boot's backup from daily at 5am to every four hours starting at 1am. We'll see if the epics slowdown problem reappears.

* Because the TMTS is significantly different from the OMCS, I started a new Mathematica model for it, based on the OMCS but with two (not four) blades at the top mass, blade lateral compliance at the top mass blades (just in case, because it's been important for quad blades in the past), and toe-out of the bottom wires in both the front-back and side-side directions (the front-back wire separation sl parameter has been forked to upper and lower values slu and sll). This can be found in the SUS SVN at ^/trunk/Common/MathematicaModels/DualLite2DBLateral .

* As is now my standard practice, I used the Mathematica version to export state space matrix elements in Matlab which I incorporated into the existing Matlab double model - if the flag pend.db is defined and non-zero, the ssmake2MBf.m file uses matrix elements for TMTS, otherwise it defaults to OMCS. The double model lives in the SVN at ^/trunk/Common/MatlabTools/DoubleModel_Production . I suspect there might be a tiny error in the way I allow for the wire stiffness in the Matlab arising from the tricky double toe-out of the bottom wires - the relative error between Matlab and Mathematica mode frequencies is better than 0.00007, but with other models I've routinely gotten 1E-12 or better. The exported matrix elements are correct because when used with no wire flexure correction (pend.stage2=0) they agree at the 3E-14 level with the Mathematica "Stage0A" results (also without wire stiffness). Any problem must be in the ssmake2MBf.m file. I'll revisit this as I have time and inspiration.

* I got Szymon to adapt the OMCS plotting scripts for TMTS ( ^/trunk/TMTS/Common/MatlabTools ) and take some test data (^/trunk/TMTS/H1/TMSY/SAGM1/Data/). Jeff K also helped. An issue we grappled with is that the Mathematica coordinate system is traditionally with +x normal to the plane of the top wires, whereas the natural coordinate system for use in MEDM screens has +L (longitudinal) in the cavity direction. So we put in a 90° rotation at a strategic point in the code.

* I started separate parameter sets for the first article and production builds: ^/trunk/Common/MatlabTools/DoubleModel_Productiontmtsopt_firstarticle.m etc). 

* I quizzed Ken Mailand for mass and MOI data for both first article and production builds. For ease of reference, I rearranged what he sent us and posted it at https://awiki.ligo-wa.caltech.edu/aLIGO/Suspensions/OpsManual/TMTS/Models .

* I got most of the rest of the parameters using the measure tool on the eDrawing at D0900419 for the first article. (The production version may well be different, but we haven't given it any attention yet.) To get the top mass d's (d0 and d1) I assumed the COM was 1.401" above the bottom surface of the bottom plate. To get the telescope d (d2) I assumed the coordinate origin was level with the round bars (where the marker seemed to be in the screenshot). This could very well be a few mm off.

* I put in blade lateral compliance the same as for the UIM blades in the quad model.

* With all of the above, the fit to TF data was pretty good except for the "R" (Mathematica "pitch") DOF. See the attachment at https://alog.ligo-wa.caltech.edu/aLOG/index.php?callRep=6066 , especially p4. The fundamental R mode is predicted a bit too low, and the highest R mode is predicted a bit too high.

* To fix the fundamental R mode, I added a tweak of +4.3 mm to d1 (the blade d). This is plausible because that's what you would get if the blades were sitting a bit lower than expected, but the mismatch could also be due to stiff cabling. See https://alog.ligo-wa.caltech.edu/aLOG/index.php?callRep=6239 . This tweak doesn't make any other modes significantly different, either better or worse. So the top R mode is still about 10% off, and I haven't been able to account for it in terms of plausible perturbations to parameters.

* A summary of the current best parameter set is on the aLIGO wiki at https://awiki.ligo-wa.caltech.edu/aLIGO/Suspensions/OpsManual/TMTS/Models/20130501TMTS_FirstArticle . Parameter values with comments giving sources are listed at the bottom. In particular, the flexure corrections are flex1 -> 0.00450482 and flex2 -> 0.00870794. Updated versions will be linked to from https://awiki.ligo-wa.caltech.edu/aLIGO/Suspensions/OpsManual/TMTS/Models .

This entry is just for a record.
I took a look at the ALS fiber path on the PSL table since I happened to be there for some other works today. The drawing below shows a power budget of the current fiber setup.

Started reworking on EY ALS table.

Green beam was injected into the chamber and PZT servo was enabled to center the beam on QPDs. Whitening gain of QPDs were very high again so we had to decrease the servo gain by a factor of 100. Whitening gain MEDM screen was all white so we left it as is.

After confirming that the beam was centered on all four irises, we started removing the Faraday from Drever lab and realigning.

Some observations:

• EOM transmission is crappier when the beam goes through the center of the input and the output hole. It looks best when the beam is almost clipping high at the input hole and centered at the output hole.
• The steering mirror upstream of the EOM was shooting the beam down significantly.
• When we put the correct Faraday in position (in the tilted beam path downstream of EOM), there're like 12 ghost beams in transmission.

We'll level the beam path and start over tomorrow though we don't know if doing so will improve the transmission quality.

I was hoping this (and power cycling the end link chassis) would get rid of errors on the bridge terminal, but there are still errors on the bridge terminal even in the init state.  

GregG & Hugh

We put the eight HEPI actuators of HAM2 in bleed mode and opened the 4-way valves and then ramped the fluid pressure back up to max.  We did this 4 times to be cautious about fluid leaks--we did this at each pier and carefully checked for leaks before ramping the pressure back down and opening the valves at the next pier.  The introduction of additional resistance has us at 28psi now with the motors running about 92% and the servo on.  We will continue these steps at WHAM3 and possibly HAM1 and/or BSC1 over the next few days.  Additional chambers will allow us to get higher pressure and so more nominal performance.
While the HEPI is locked, we did see some readout change on the IPS.  The signs are all the same and the largest is about 300 counts or ~0.0005".  I suspect this is mechanical distortion of the Actuator itself with the pressure introduction.  Since the IPS is all attached to the actuator both the Flag (unsuspended) and Sensors (suspended), I don't think this can be checked independently.  I would venture that the Platform has not actually moved.  After a couple days of bleeding, we'll switch the Actuators to run mode.  This will likely change the pressure/IPS state again so hold on!  We'll likely want to have enough Actuators on line so that we can servo the pressure at nominal level(80psi, 70diff) so the introduction of additional actuators will not change the actuator distortion/IPS 'zero'.

I created the new safe.snap files for the EY systems. I made the name change to the alarm handler files (both CDS and WATCHDOG). I found I had not actually changed h1iopiscey from PEM to ISC, so I changed that and restarted all models on this front end. Several DAQ restarts were performed for these and user model changes today. The PSL ENV slow controls channels were added back to the frame.

These are the TF/Spectras Test Results for HSTS I1-PR2

The polarization of the IMC REFL beam on IOT2L was measured.
It was found to be about 80 degrees off from S-polarization while pure S-polarization is desired for the optics in the RFPD paths.
This explains the recent funny splitting ratio of the 50/50 BSs in the RFPD branches [1][2].


Background :
 We found that the 50/50 BSs were not splitting the beam with a correct splitting ratio. To understand the current situation we decided to measure the actual polarization.

 
No polarization correcter :
 Apparently there is no polarization correcter in the current setup. This is another reason why the splitting ratio was funny. We used to have a HWP to rotate the polarization to S (see for example [4]). However I found that this had been put aside out of the main path for some reason. I guess this is because the setup is still under the process of rebuilding. Anyway according to the latest diagram [3] there will a calcite polarizer in addition to the HWP which then spatially separates the S and P polarizations. A quick fix would be to simply place the HWP again in the path if necessary.


Measurement:
 I inserted a corner cube PBS (PBSC-1064-50) to measure the polarization in-situ on the IOT2L table. The measurement was done in two places : one right after the bottom periscope mirror and the other after the window (IO_MCR_AR1). I put a convex lens in front of the PBS to make the beam go through the PBS. Note that the measurement was done before I increased the incidnet power on the IMC.

  Measurement 1 : Right after the bottom periscope mirror
  transmitted light (P-pol) = 141.0 mW
  reflected light (S-pol) = 26.6 mW
  polarization angle from S-pol = atan(141 mW / 26.6 mW) = 79.3 deg

  Measurement 2 : After the window (PBS was placed after IO_MCR_M6)
  transmitted light (P-pol) = 4.72 mW
  reflected light (S-pol) = 0.75 mW
  polarization angle from S-pol = atan(4.72 mW / 7.5 mW) = 81.0 deg

So the beam is pretty far off from the desired polarization of S currently. The PBS and lens were removed from the table.


[1] LHO alog 6264 "DC calibration of IMC WFS"
[2] LHO alog 6297 "IMC incident increased to 1 W"
[3] DCC D0902284-v9
[4] DCC D0902284-v7
 

- Vacuum alarm: criopump 5 were refilled, Kyle mention that tomorrow and next Tuesday, Wednesday and Thursday will refilled other criopumps, so, expect this alarm

- PSL alarm: there is a problem with H1:PSL-OSC_LPSCLSD and H1:PSL-OSC_PWRDOGON channels, neither M Rodruck, nor Dale understand what is going on. Will need further study

- FMCS alarm: max temperature of MID X and Y will be set at 85F. The sensor for H0:FMC-CS_LVEA_ZONE4_B_DEGF seems that is broken, Ski will unplug it.

- Dave restarted all DAQ at 11:42

- SUS watchdog alarm: ETMY and SEIB6 were all invalid. Dave, Cyrus, Richard diagnosing network switch problem at EY. All EY DAQ data bad since 9am. Cyrus found a broken fiber. Solved ~13:30.

- LVEA Crane survey continues

- M Rodruck and Filiberto installing cables into H2 LEA for Pcal pre-alignment

- Keita working on the TMSY ~14:00

- Robert S. from ~12:40 to 2:30 working outside, tube's enclosure, between OSB - MX

- Kiwamu increased the laser power into the IMC to 1W

- Thomas working on viewports, laser into HAM1 has being shuttered, contact him before unshutter it
 

-Moved the Genie snorkel lift from High Bay to LVEA so that the LVEA camera could be cleaned for Richard and then moved the Genie back to High Bay so it could be inspected by Mid-Columbia. 
-X End work continued. Test stand cleanroom was rolled out of the VEA to the middle bay so that picking eyes could be fitted and attached. The picking eyes, taken from the "dirty room", required a slight modification before they could be attached. Holes were drilled in the cleanroom frame and the eyes were attached this afternoon. The table that sits on top of the TMS Bosch frame was moved into the lab to clear space in receiving. Work to clear interferences for IAS table placement is on-going.
-Provided support for OpLev work: Mick worked with Thomas and Tyler fabbed a cover for an OpLev camera.
-Provided support to SEI.

The laser power incident on the IMC was increased to 1 W per WP3869.
It will stay at this power level during HIFO.

Preparation
In preparation to increase the power I did the following things:

•  Removed a beam dump which had been in the main PSL path right after the EOM on the PSL table.

This dump was something people put to block the beam during the high power adjustment in the last two days.

• Measured the power of the main PSL

After the EOM = 1.203 W

In front of the bottom periscope mirror = 167.7 mW
(This was then increased to 1.00 W)

• Measured laser power on the IOT2L to make sure that increasing the power doesn't damage the diodes.

Note that I intentionally misaligned MC2 during the measurement on IOT2L by disabling the pitch offset of 407 urad in M1.

This was because I wanted to avoid fringing in the reflected light.

Adjustments.

  The incident power onto the IMC was adjusted to be 1 W by rotating the half-wave-plate in the last attenuation stage in front of the PSL periscope. Note that this rotational stage doesn't give us more than 1.2 W since the power is already limited by another attenuator in the upstream. Then I checked the power on the diodes on IOT2L to make sure they are working OK with the new power level. The power were measured to be :

Length RFPF = 9.3 mW
WFS A = 6 mW
WFS B = 13.6 mW

All of them show reasonably big DC signals in the digital system and seems fine although I didn't check the RF signals yet.

[Dick, Kiwamu]

 We took a look at the IMC demod phase shifter [1] which had been found to be out of Beckoff's control the other day last week [2]. The conclusion is that it magically recovered by itself and became under Beckoff's control again. Anyway we set the delay by the hardware switches and disabled the digital switching as this is relatively safer than setting it digitally. There should be no impact on the IMC locking.


The optimum delay setting
   The delay is set to be 14.4375 nsec (= 1/16 + 1/8 + 1/4 + 2 + 4 + 8 nsec)
 where the I signal is maximized. This corresponds to a step setting of 231=(1+2+4+32+64+128) in the digital system. Note that the IMC modulation frequency is at 24078360 Hz.

The Symptom
 The symptom we saw last week was that the delay time didn't change when we changed the digital values in the corner Beckoff. I don't know what had happened to the electronics and digital system. Somehow we were able to change the delay from the Beckoff today.

The right half of the device is not functioning
 This is not important. A sad thing we found is that the right half of the delay line device doesn't seem working for some reason. We are not going to fix this because we haven't been using it and also we are not going to use it. Dick found that the loss of the circuit heavily depends on the amount of the delay and sometime it can reduce the ~15 dBm input signal down to -20 dBm or even less at the output port. We are guessing that there is some kind of loose contact in the circuit.


[1] DCC S1103425
[2] LHO alog 6265 "IMC locked, relocking well, visibility is good, but not TRANS beam, as it is clipped by it's bellows."