(Aidan B, David H, Thomas V, Alastair H, Matt H)

 (Note this is talking about TCSx table)

So finally some success. The first polariser after the laser was moved from before the AOM to after the AOM (and positioned such that the transmitted beam from the AOM goes through the polariser but the first order beam does not). It was then quite easy to alter the polarisers so that I got a minimum power reflected of off the 2nd polariser after the Beckhoff controlled HWP of 4.5 mW when in CW mode (HWP setting of 36.4 degrees gave this maximum power). The power transmitted onto the high power, power meter was 44W. (see top drawing on attachment).

We now can begin aligning in earnest again. However as we want to start running the laser around the clock soon, we started putting some other provisions in place first.

• The manifold was modified so that we could use the water cooled beam dump and the water cooled beam dump is now positioned after the first polariser after the HWP, so we can now dump all the power there as designed.
• One of the quadrant thermopiles has been placed on an x,y, z, translation stage so we can start calibrating these quadrant thermopiles
• Temperature sensors were placed on the AOM, AOM drive, RF drive and the water cooled beam dump. One will also go on the manifold also once I get a bracket modified to hold the thermistor in place. To see these temperatures go to the main CO2 screen, click on the ethercat tab and you will see 6 temperature sensors (see pic 1 and pic 2). Temp sensor 1 is the AOM, Temp senosr 2 will be the manifold (not plugged in yet), Temp sensor 3 is the AOM drive, Temp sensor 4 is the water cooled beam dump, temp sensor 5 is the RF drive and Temp sensor 6 is a spare (not plugged in). I have asked that these be relabelled with something sensible (apparently names are generted in Beckhoff).
• We have started putting up laser barrier shields at the edge of the table near the laser

I also was going to put in the PD's that will be used for the Intensity stabilisation as they arrived today. However they dont physically fit. So we are going to have to come up with a different layout. Aidan is currently looking at what we will do. We also tried to put a breaker box supplied by Ben Abbott between the ISS box and the feedthrough. We had some issues with the connectors at the feedthrough working so we reverted back to the old setup. David was modifying so that we can try again tomorrow to connect this up

We have continued aligning after the polarisers and now have the 1st flipper mirror, lens and 2" steering mirror aligned. I thought this to be a good stopping point for the night as I am confident I can get the rest aligned tomorrow now. I have put a beam dump after this mirror to dump the beam into, so the laser can be started up at any stage if I am not here and all beams should be dumped. (see second drawing in attachment of sketch what done thus far).The Beckhoff controlled HWP has also been set to 36.4 degrees and so should dump the majority of the power into the water cooled beam dump.

Pic 3 shows the table layout as currently done

Pic 4 the water cooled beam dump (note hose clamp holds temperature sensor in place)

- Stood up CSD for H1LSCAUX, H1LSC, and H1ECATC1PLC2.
- Updated the xml files for H1LSC and H1ECATC1PLC2 to handle ALS and PRMI states.
- In particular, for the purpose of setting its control state, I split the LSC in four separate systems:
  - The IMC part (H1:LSC-IMC_STATE)
  - The central interferometer part (H1:LSC-PRMI_STATE)
  - The ARMS & ALS part (H1:LSC-ARMS_STATE)
  - The photo diodes (H1:LSC-PD_STATE)
- The xml file easily allows to merge them later or add more / different states.
- The H1:LSC-PRMI_STATE variable currently can be set to PRX, PRY or PRMI
- In addition there is a H1:LSC-PRMI_PD_SELECT variable, which has values of VAC_PD, AIR_PD and 3f_PD.
- In addition I added
  - H1:LSC-MISC_STATE and H1:LSC-PSL_STATE for some additional junk.
  - H1:LSC-MATRIX_LOADING, which punches H1:LSC-PD_DOF_MTRX_LOAD_MATRIX if set to automatic (or does nothing in manual)

One Warning:
 - I spent some time trying to make sure that the H1ECATC1PLC2 does not interfere with guardian or Beckhoff auto-locking. But it is possible that I missed some channels (since there is no channel declaration available in either). So if we have issues tomorrow, we should set H1ECATC1PLC2 into dryop mode and watch for differences.

A dtt measurement was started for the test mass to test mass L2L transfer function of ETMX (using ESD drive) on opsws2. It is saved under QUAD/H1/ETMX/SAGL3/Data/2014-04-30_H1SUSETMX_L3_L2LPY_SweptSine.xml
An other one was started on opsws6 for ETMY UIM

On monday night, we were able to measure the top mass to test mass L2L transfer functions on ETMy and ETMx, using the ALS-{X/Y}_REFL_CTRL signal for the response. The idea is to measure and invert the plant for each of the following stages (TOP UIM and TST).

We did the measurement in two configurations :

1- oplev damping feedback to UIM on
2- oplev damping feedback to UIM off

In both cases, the slow feedback was ON (using the inverted fit from the model) and the length to pitch and length to yaw decoupling filters were engaged (gain of -1).

The L2L measured plant is sligthly different when oplev is on/off. With oplev on, the Q of the first QUAD resonnance is higher.

The data was fitted for the 4 measurements (using the script fit_topLong2tstLong.m under QUAD/Common/FilterDesign/Scripts), and the inverted plant was installed in the LOCK filter banks FM1 (tuned for oplev damping on : "invL2L") and FM2 (tuned for oplev damping off "invL2L2"). The fitting is summarized in the attached plots.

The phase of EX measurement is off by 180 degrees for some reason.

The results were saved under
EY
/ligo/svncommon/SusSVN/sus/trunk/QUAD/H1/ETMY/SAGM0/Data
2014-04-28_H1SUSETMY_M0_L2LPY_OL_OFF_SweptSine.xml
2014-04-28_H1SUSETMY_M0_L2LPY_SweptSine.xml

EX
/ligo/svncommon/SusSVN/sus/trunk/QUAD/H1/ETMY/SAGM0/Data
2014-04-28_H1SUSETMY_M0_L2LPY_OL_OFF_SweptSine.xml
2014-04-28_H1SUSETMY_M0_L2LPY_SweptSine.xml

The higher temperatures pushed the 7805 of the EX CFC into thermal shutdown. We swapped the regulator, added a large heatsink and run without a lid. At a more opportune time we need to hammer in the copper heat pipe.

Some seconds after I and Arnaud started the EX ESD TF measurement, EX PLL failed. VCO frequency readback was giving some nonsense numbers like 65MHz and such (should be about 79MHz), beat note was going around 0, PDH modulation readback was also nonsense, and we were even reading some frequency out of unused ports.

Daniel was suspicious about the DC regulator (7805) thermally overloaded, because that chip is without any heat sink (and, as it turned out, it was not even screwed down to the board itself).

We went to the EX, shut it down, and after a while powered it up again, and it read the frequencies fine. We pulled the unit, Daniel swapped the chip and put a heat sink on it, which unfortunately made it impossible to put the top lid of the chassis, but anyway we left it like that for the moment.

After putting it in the rack, it seems like it's working fine again.

Note that a proper modification should be made to this unit later, as well as all 3IFO and spare units.

Conlog is back up and running and monitoring the channel list that Dave generated yesterday. I disabled the crontask that logs the disk usage and number of database rows because I know that the latter is a long query. I also disabled the MySQL binary logging that is used to report the frequently changing channels. I'm not sure if this has helped, the CPU usage for the conlog task is still at 100%. There is also a high I/O wait.

Attached is a plot of the queue size over the last two days. I stopped conlog when I found it high and plateaued yesterday afternoon. The queue size seems to take a while to come down after startup now, but it remains low afterwards.

I've done some tests on ITMY, trying to reduce the excessive YAW motion seen by the OPLEV. Our guess is that there is some magnetic coupling/interaction between the actuators and the T240s: we can observe some pickup in RZ when the Z controller is ON.

I've tried 3 different configurations:

1) ISI controlled with Tbetter blends everywhere

ref config

2) ISI controlled with T750mHz on Z (stage 1 & stage 2)

By putting a higher blend, we relax the force induces by the actuators and therefore the pickup in RZ

3) ISI controlled with T750mHz on Z, HEPI Senscor Z turned ON

By turning on the sensor correction on HEPI we improve our performance in Z at the microseism.

See plot attached

In the third configuration, we obviously degraded PITCH, but improved a little YAW. More tuning might lead to a better trade off.

- 9:02 am, Jason to CS VEA, HAM6 area, SR2 alignment setup.
- 9:05 am, Justin to X-End VEA, inspect ALS table.
- 9:05 am, Jodi to CS VEA, West bay area "to cause trouble".
- 9:09 am, Aaron to CS VEA, to pull cables for TCS cameras and fiber for hartmann sensor (Jodi said it and Aaron did it).
- 9:17 am, Thomas and David to CS VEA, assembly of periscope for Hartmann sensor.<-- done 10:45 am.
- 9:21 am, Corey to CS VEA, squeezer area to retrieve components.
- 9:23 am, alarm! alarm! BSC1, BSC2 and BSC3 SUS screens DOA, they were all frozen, we blamed Aaron and his pulling of cables, Jim B restarted all models.
- 9:50 am, Justin to X-End VEA, found something out of order on ALS table, tape on hand to fix it.
- 9:41 am, Betsy to CS VEA, inspection of HAM4 area.
- 10:12 am, Hugh to CS VEA, West bay area hunt for parts.
- 11:13 am, Jeff and Andres to CS VEA, work around HAM4 area.
- 11:42 am, David and Thomas CS VEA, TCS X-arm cabling and electronics.<-- done 12:08 pm.
- 1:18 pm, David and Thomas to CS VEA, more TCS work.
- 1:21 pm, Karen to Y-End VEA, to clean.
- 1:31 pm, Justin to CS VEA area transitioning to Laser HAZARD.
- 3:45 pm, David and Alastair to CS VEA, TCS Y-arm table inspection.

(Sheila, Alexa)

We had thought that maybe the 1/f noise seen in COMM came from the PFD. Today we have ruled that out. We did this by replacing the PFD with the spare IQ demod channels of the IMC. In this confirgaution we measured the beatnote signal to be 250mVpp, and set the COMM PLL Input gain to 31dB. This resulted in a loop with -18dB less gain than the nominal configuration. We then used the control signal to measure the noise.

I have attached a DTT with the following traces:

• REF 2-3: signal with demod and input 1 gain 31dB (corresponds to UGF of ~3kHz)
• REF 4: signal with PFD and input 1 gain 27dB (nominal configuration corresponds to UGF ~30kHz)
• REF6: signal with PFD and input 1 gain 9dB (corresponds to UGF of ~3kHz)
• REF10: signal with PFD and input 1 gain 18dB

Clearly, the PFD does not seem to be the culprate. These measurements also suggest that we should lower the UGF of the COMM PLL loop.

With the demod in place and the input gain at 31dB, I also measured the amplitude spectrum out of the IMON of the demod. I have attached the data.

Betsy, Jason

After rounding up step stools and tooling needed to be able to work in HAM4, I went into the chamber in order to mount the corner cube in front of the SR2 suspension for the first IAS sight shots.  In order to set the corner cube mount into place I had to move:

1) 1" witness plate and assy that was vertically mounted on the front of the SR2 structure

2) 2 SR2 dog clamps of course

3) The large steering mirror (HWS?) parked in front of the sus structure and some of it's dog clamps.

As well, the witness plate that also in front of the sus structure will need to be moved as it is in the line of tool fire.  I've removed the 1" witness optic and put it in a holder to ship back to CIT (presumably).  We're still apparently sorting out what to do with the witness plate and optic which was placed by Kate on her last visit.

Other CC note: The particle counter in the SW corner of the cleanroom was consistently reading 14 or 25 for 0.3um particles, when I happened to look at it.

Jason will post X,Y,Z measurements of the optic position in HAM4.  We've already started to tool up the SR2 sus to make the shifts he notes, but ran out of time to switch over to laser hazard.  WIll resume tomorrow.

Jeff B. brought to my attention that the purge-air flow in the combined volume of HAM4, HAM5 and HAM6 seems to be fluctuating in a periodic fashion -> I investigated and found that the low pressure output pressure regulator supplying purge air to the LVEA is stuck -> As such, the output pressure of the regulator (to the LVEA) is fluctuating between the nominal 1 psig and 1/2 psig as the input to the regulator fluctuates between the nominal band of 120 psig and 80 psig -> I'll order a part and get this fixed but in the meantime, in-chamber work can continue. 

(Aidan B, David H, Thomas V, Matt H....Alastair H (remotely))

We have been trying to align the table the last few days, but ran into an issue with trying to get a good extinction of the beam reflected off the two "wavelength" branded polarisers that are after the Beckhoff controlled HWP.

First for a little bit of history. For the two table builds at LLO, the reflection off the 2nd of the polarisers after the Beckhoff controlled HWP could be minimised to a couple mW as measured by a power meter.  (in fact I think I even heard could get down to 0.2mW). However, the two tables at LLO were built up only in "phase 1" build. Thus they do not have things like the AOM installed (which will be used for intensity stabilisation).

Here at LHO we are trying to do the phase 1 and phase 2 builds at the same time to work out as many issues as we can before trying to build up the other table at LHO, and do the phase 2 builds at LHO.

When doing the alignment the first time around, we found that for ~10W (about 20%) CO2 power we couldnt get the power reflected off the polariser to be anything less than ~10mW. We tried various times to fine tune the rotational angle of the polarisers as the power reflected is very sensitive to angle. However no success. We decided to simplify the setup to have a look at what was going on.

Firstly we put another HWP right after the ouput of the laser and then we looked at the performance of the very first polariser (II-VI brand) that is right after the laser. At an angle of 60 degrees on the HWP we got maximum transmission through this first polariser, and by fine tuning the angle of the polariser, we can get an extinction ratio of around 200:1 (p to s polarisation) which is what we roughly expected for the laser output (and double checked this was the case by removing the HWP and seeing that the results for what is transmitted and refected from the polariser essentially stays the same). So we are getting what we expect from the laser.

We then experimented with what we see when we placed wavelength type polariser after the AOM (so setup is laser, HWP, polariser, AOM, polariser). In this simple setup we couldnt get the reflection off the polariser after the AOM to be at a low power level like expected (we got around 0.43W  at only 20% power level). Removing the AOM decreased the reflected power off the second polariser by around half this amount. We even tried moving the HWP to between the two polarisers and playing with it and looking at what we see, but minimum reflected power could get was still around 200mW (at 20% power setting of laser on PWM mode).

So decision was to make a real simple experiment and mimic what essentially LLO has (except for a bunch of steering mirrors between first polariser and Beckhoff controlled HWP). So we had a setup of laser, polariser, HWP (mimicking beckhoff controlled HWP), polairiser, polariser. With this setup we were able to get roughly the results see at LLO (ie a few mW of power reflected off the last of the polarisers when laser running in CW mode at full power). 

So now went back and went for broke and put everything back as should before phase 2 layout (ie AOM back in, polarisers after beckhoff controlled HWP), and after realigning/checking alignment of everything, the minimum power we could get off the reflection of the 2nd of the polarisers after the Beckhoff controlled HWP when laser is in CW mode is ~95mW AAAAArrrrrggggghhhhhhh. At a hunch I ripped the AOM out (it only transmits the beam so should not affect the alignment pulling it out), and immediately the power reflected off the second of the polarisers after the HWP went down to a few mW. 

Thus it seems the AOM is affecting the polarisation of the beam. We are going to look further into it (may be due to some kind of stress being induced to the AOM in someway), we may also look at changing the layout (move the first of the polarisers to after the AOM) to mimimise the affects of what the AOM is doing to the polarisation of the beam. The hunt goes on..................

All the BSC-ISIs foton files have been updated with the good switch output coniguration, according to the list posted in the SEI log (https://alog.ligo-la.caltech.edu/SEI/index.php?callRep=439)

I had to restart the h1guardian0 machine. Commissioners reported that the guardian IOC was still running, but the guardian processes were unresponsive and the log windows would not open. I was able to ssh into the machine, but could not run any command with the error "fork: no memory". Since I could not execute the "reboot" command, I rebooted the machine by pressing the front panel RESET button.

I am setting up sysadmin monitors on this machine to report processor space and memory usage. The machine had only been running for 7 days. Stefan reported that he was running a guardian in dry-run mode recently, other than that regular operation of guardian over the past week.

Kiwamu, Arnaud, Sheila

We spent this evening trying to get UIM to test mass length to length measurements.  We do this with no slow feedback to the top mass.  With optical lever damping on, we saturate the PUM at high frequencies, so it has been easier to make the measurements with OpLev damping off.  We have reasonable coherence from 5Hz down, saved as 2014-04-29_H1SUSETMX_L1_L2LPY_SwpetSine_OLDamp_Off_5Hz_to600mHz.xml

We are leaveing one measuremetn running on opsws6 with an envelope that we have tuned to get the low frequency part, saved as 2014-04-29_H1SUSETMX_L1_L2LPY_SwpetSine_OLDamp_Off_1Hz_down.xml.

We briefly tried using the UIM for feedback, with a theoretical plant inversion filter, with no obvious sucess. 

Kiwamu fixed the calibration of REFL_Y_CTRL, makiing it identical to REFL_X_CTRL. 

Mark B. and Gerardo

Yesterday (4/22/14) Gerardo and I measured the vertical mode Q of the OFIS for three different positions of the ECD block to try to get the Q in the specified range of 25-30.

The OFIS was set up on the optical bench in the H2 laser enclosure. The ECD block sits on a tray below the payload which is supported by four groups of vertically pointing screws at accessible positions around the edge of the structure. Gerardo had earlier attempted to set the ECD block at the nominal height using the spacer tool provided but found that this was too high and caused interference. He therefore lowered the block until it was just barely clear plus approximately an extra two turns of the 1/4-20 screws. This was our starting point for further adjustments.

To measure the vertical Q, we used the laser pointer and QPD from the monolithic violin mode setup and used a convenient screw on the top of the payload to partially block the beam. We displayed the "pitch" output of the QPD box on a digital oscilloscope with a 1 sec/div timebase and photographed the screen to capture the data. I read off the peak positions with GraphClick, and worked out the logarithmic decrement and Q with Mathematica.

For the initial position, the Q was 10.7. We lowered the ECD by one turn on all the screws and got Q = 18.9. We lowered the ECD another half turn and got Q = 23.3. Finally, today (4/23/14) we lowered the ECD another 3/4 turn and got 27.8, which is in spec.

Attached is a JPG of the setup, a PDF of all the screenshots, and for the fourth and final run, the Mathematica notebook, PDF thereof and the raw data.