This morning I measured the sensing matrix for the ALS X WFS, using the oplevs:

The result for Yaw looks good:

1177countsWFSA YAW/urad ETMX yaw (61 degrees)

565counts WFS B Yaw/urad ETMX yaw (55 degrees)

-815counts WFS A YAW/urad ITMX yaw

533 counts WFS B yaw/urad ITMX yaw (39 degrees)

For pitch the two sensors are nearly degenerate:

-268 counts WFS A PIT /urad ETMX PIT

-999.6 counts WFS B PIT/urad ETMX PIT

201 counts WFS A PIT/ urad ITMX PIT

898 counts WFS B pit/urad ITMX PIT

Based on these matrixes, we would be able to close two DOFs in YAW and one pitch DOF.  We know that the beam profile is really bad in PIT on WFS B (attachment to alog 10774), so we might want to try fixing this before we try lcking the second pit DOF with high bandwidth anyway. There is also cross coupling from PIT to Yaw, which might become a problem. 

The measurements are saved in home/sheila.dwyer/ALS/HIFOX/WFS/

WFS_sensing_matrix_ETMX_PIT.xml ect.  All measurements were made by sending a fither to PUM at 1.5Hz.

Daniel, Stefan, Sheila

Today we spent some time carefully double checking the calibration of the ALS COMM signal. 

The first screenshot is a repeat of the measurement from alog 10930, locking with the additive offset and then moving the offset over resonance. The current calibration is 0.127, this is loaded in LSC_REFLBIAS_GAIN so that REFLBIAS_OUT is in units of Hz. 

We moved the pole in the additive offset path from 0Hz to 1mHz to prevent the integrator from running away. 

We also changed the gain on the common mode board in1 to 11dB (to avoid saturations in the additive offset path), common comp is on, in2 gain is 6dB and the REFL DC BIAS gain is 50. 

in this configuration we measured the gain in the additive offset path, and got a 3Hz ugf. 

We are now using the ALS-C_REFL_DC_BIAS_OUT calibrated because this is a DQ channel. This calibration has a gain of 0.g and a zero at 3Hz, the ugf of the additive offset path.

Using this measurement we get an rms of 50-200Hz depending on the time of the measurement.  The variation is below 1 Hz, and seems to change with the seismic noise. 

Aidan. Thomas. Dave H.

We've received the remaining parts for the CO2 laser projectors + assorted HWS parts. Currently I've unpacked 22.5 boxes out of 26.

I also added some calibrations to a selection of front-end channels. These have been safe snapped so we can burt restore them. See the attached status PDF for details.

Decoupled RGA from Y1-1 port -> Opened GV10

Pressure alarms along y1 from accumulation experiment

900 Hugh and Mitch payloading HAM5

915 Jim Correy Jeff working ETMY

919-1200 Aaron working on noise eater at EY

940 Fil making repairs t board in ISC_R2_RACK to facilitate PRC measurement

948 SUS working up test stand area for welding prep

1030 Jodi working at MY

1300 Arnaud taking tf's at EY

1317 Fire maint and HFD onsite

1345 Jeff/Andres working on SR2 at HAM5

1427 Gerardo and David O going laser hazard in H2 enclosure

Not sure how I did it, but I accidentally hit the back button on my browser while making an entry, and went back to see that the entry I was just about to post had vanished.  :(

Here is the list of commissioning task for the next 7-14 days:

Green team:

• Generate a new calibrated spectrum covering the very low frequencies.
• Look for clipping in green transmission.
• Make a mode scan of the red resonances.
• Test the length feedback path to the ETM top suspension point to suppress microseism.

Red team:

• Center the red QPDs in EX.
• RF REFLAIR45 whitening.

Blue team (ALS WFS):

• Remeasure alignment sensing matrix.
• High bandwidth WFS.
• Automate drift alignment.

Blue team (ISCTEY):

• PLL fiber locking.
• Prepare noise eater remote switch.
• Add WFS.

SEI/SUS team:

• ETMY diagonalization.

The ITMy lower ring heater had a busted edge as well as busted macor element connector. These pieces had broken during an adjustment earlier, but I suspect it was because the glass former is oversized compared to the macor element. The glass former and nichrome measured out at 0.281" while nominally the macor element that it seats in is 0.256". Trying to fit the pieces together caused the macor to start chipping and was going to obviously require a lot of force. It seemed like it would just cause the same problem all over again.

Jax, Stefan

We verified that the whitening stage 1 of REFLAIR_A_RF45_I is indeed not switching on the analog side. We checked that the command bit (pin 25 / GND=pin 20) makes it to the board. Thus Jax will pull the board tomorrow and debug it..

Details:
Rack: ISC R2 slot 32
S/N: S1101590
Assembly: D1002559 (board2)

On Friday I replaced the glass former that had broken on ITMx. After the glass former was replaced the ring heater was flushed and run in the airbake oven. The lower ring heater attached to the quad structure without incident. Cables were re-routed and tied down with stainless steel strips. Attached are the install photos. 

The ITM03 test mass and it's PUM-ETM01 have been installed in the lower structure and the lower structure has been parked in the fiber weld cleanroom.  Equipment setup is almost complete.  We anticipate firing up the CO2 welder tomorrow.

Laser Status:
Output Power : 28.2w
FRONTEND Watchdog green
HPO WATCH is red (High Power Oscillator Offline)

PMC: 
Locked for : 0d 23h 16m
Reflected power : 1.3w
Power Sum : 11.7w

FSS: 
Locked for : 0d 0h 1m

ISS:
Diffracted power : 5.8% (recovering from sat event)
Last Saturation Event : 0d 0h 8m

Mitchell and I added 200lbs to the HAM now holding 800 lbs.  The 50lbs in the middle is sitting on the 600lb leg element on four 1/16" thick viton pads.  The three other 50s are on the ISI Optical Table but we couldn't get them to be non-rocking, two imperfect planes...  So we turned the masses over and set them on just three pads.

Next step, unlocking, torquing, cabling, TFs.

On friday, I had a chance to test the Y2Y UIM filter, by taking an open loop transfer function driving in yaw from uim and looking at the test mass optical lever. The open loop looks as expected, falling at 1/f^2 after a resonnance at 0.6Hz. The attachement shows the open loop without vs with the filter.

[Stuart A, Jeff B]

Templates have been committed to the sussvn for the H1 TMSY (TMTS) suspension, derived from L1 TMSX, as follows:-

2014-03-24_0900_H1SUSTMSY_M1_WhiteNoise_L_0p01to500Hz.xml
2014-03-24_0900_H1SUSTMSY_M1_WhiteNoise_T_0p01to500Hz.xml
2014-03-24_0900_H1SUSTMSY_M1_WhiteNoise_V_0p01to500Hz.xml
2014-03-24_0900_H1SUSTMSY_M1_WhiteNoise_R_0p01to500Hz.xml
2014-03-24_0900_H1SUSTMSY_M1_WhiteNoise_P_0p01to500Hz.xml
2014-03-24_0900_H1SUSTMSY_M1_WhiteNoise_Y_0p01to500Hz.xml

These can be made available by svn'ing up the /ligo/svncommon/SusSVN/sus/trunk/TMTS/H1/TMSY/SAGM1/Data/ directory.

Let me know if there are any issues with their use.

n.b. the reference included in these templates is for L1 TMSX at Phase 3b (in-vacuum) of testing.

Measuring the COMM noise with the refl DC bias path engaged gives repeatable results, while we did not repeatable results without it.  However, something seems to be wrong with our calibration.  Today, when the refl bias path is not engaged we wander over the peak in about 10 seconds, and all th way off resonance, so we know that the COMM noise is at least a fwhm of the IR resonance in the arm, 164Hz. 

When we lock the refl bias path, measure a spectrum and correct for the gain of the refl DC bias path, the rms should be the noise of the refl bias path.  However, we are consistently measuring a noise around 35 Hz (with cavity pole corrected for) or around 9 Hz without taking out the cavity pole.  However, we know this is wrong. 

At least with a repeatable measurement we can evaluate what make the noise worse and better, even if we don't yet trust the calibration. Attached is a plot of the COMM noise measured with refl DC bias engage, the gain of that path corrected for but not the cavity pole.  In the blue trace the OpLev damping was on for both pitch and Yaw, in the green trace the pitch damping was off on both the ETM and ITM.  The coherence are shown in the bottom panel, the solid lines were measured with no damping, the dashed lines with damping.

With the damping on, the noise at 0.45Hz is reduced by a factor of 5.5, although it doesn't seem to change the rms much in this plot. 

The green trace was measured with lower bandwidth because the lock was not lasting more than a few minutes today, especially with the damping off.

Dave O, Stefan

While attempting to lock the PRC we noticed that POB_Air_B_RF_I_Err was low on signal. We traced this back to a low de-mod signal (see attached plot). We traced this down to a tripped fused in the ISC_R2_Rack. This tripped on the 17th March. We tried to reset it but it simply re-tripped again.

When we locked PRX and PRY, we were also surprised that we needed to flip the feed-back sign in PRCL to lock on the carrier (compared to the settings the LSC guardian uses).

(Sheila, Daniel)

We used the normalized PDH signal to feed back to the additive offset of the common mode servo which in turn moves the mode cleaner and the laser frequency. The loop bandwidth was 20Hz with a 1/f shape. This kept the red laser light on resonance in the arm cavity for good. We then swept the offset of the normalized PDH error signal to scan the cavity resonance. The attached plot shows the sweep. It took about 20 seconds. The FWHM as measured by the red transmitted light corresponds to 49.7 units. However, it should be 165Hz. The calibration factor was set to 0.208 (from 0.063).

We mounted the second green Faraday on a 4-axes mount and reworked the Green injection path to make the beam shape less clipped. We needed to go close to the edge of the EOM and Faraday aperture to get the best beam quality.

As for the EOM, the best beam shape was achieved when the beam is very close to the top edge of the output aperture, maybe it was already touching the hole. We backed off the height adjustment screw (closer to the output) of the EOM mount by half turns so there's no apparent clipping but it's still very close. With this backed off position the beam shape was not as good but we called it good anyway as we couldn't do anything about it.

Anyway, since the center of the aperture for Faraday as well as EOM is NOT the best position as far as the beam quality is concerned, Faraday and EOM should be on adjustable mount. The first Faraday is still fixed, and this means that the beam is not horizontal along the beam path through the first Faraday, which is OK but not ideal (e.g. the beam is not completely centered on the first lens).

We still don't know if this new beam path arrangement is any better  or worse than before.

We took some beam profile measurements, which Sheila will post later. Quality of the injected beam is better, the beam coming back to WFSA looked better than before, WFSB was worse.