The original PSL chiller has been fitted out with the vortex style flow sensor.  In
turning the crystal chiller on, we found that the controller unit was faulty and did
not display the Termotek logo on start up.  The controller was replaced and the chiller
powered up okay.  We ran the chiller with the outlet connected to the inlet without any
problems.  The flow sensor calibration factor was changed to 0970 to account for the
vortex sensor.

The exercise was repeated with the diode chiller.

At the moment the chillers are in the large item access area, waiting for a convenient
time for us to roll them back to the chiller room.  The crystal chiller needs another
pigtail cable to be made.



JeffB, Peter

No real changes from the report yesterday afternoon.  That data was from the afternoon after things quieted down in the LVEA.  Data from this morning ~0030pdt, look pretty much the same.   There are bands of elevated signal compared to the references: ITMX & BS ST2 Verticals below 20Hz.  The BS Stage2 Corner2 signals are lower now by factors or 2 & 3 above 20 Hz (good thing.)  The ITMX sees increased noise above 20Hz on V1 both stages and on ST2 H2 above 10Hz.  In general, ITMY looks little changed and pretty good.

Happy if RichM or another well studied would look at these too.

10 day trend.

Noticed it on the way out...

Evan, Stefan

We fine-tuned the MICH correction todonight.
- Added the SB300vio BS violin stop band filter to MICH_FF to cancel their effect.
- Measured MICHFF_OUT to DARM_IN twice:
    1) drive disconnected at the ITMY. This measures the MICH_OUT to DARM_IN path.
    2) MICH_FF input off, driving MICH_FF. This measures the MICHFF_OUT to DARM_IN path. 
  This data is in plot 1.

- 1)/2) is the desired filter, shown in  plot 2.

- Finally, we used a p:60:z:80 filter to fine-tune the phase a bit. (Plot 3) This significantly improved the achievable subtraction.

Evan, Stefan,

Our late night work was hampered by repeated lock-losses engaging SRC2 loop during the DRMI phase. The few times we made it through that stafe, we lost it in the IFO ASC stage, when the SRCL2 loop gets extra gain.

We tried both a high SRCL offload and low SRCL offload configurations (Gain of 1 and 0.1 respectively in SRM M2 stage.) The high SRCL offload configuration resulted in a 18sec oscillation, growing to a lock-loss.  The low configuration (the default) also broke the loss several times, but we are not sure why.

Sheila, Evan, Stefan

We remeasured the required SRCL FF filter today. The transfer function changed significantly.
The only thing we know we changed was the POP_45 phase (H1:LSC-POP_A_RF45_PHASE_R) from 66deg to 58deg - this minimized a SRCL drive in MICH.

The fit functions are roughly:

May 11: p:0,0  z:2.28571+31.9183i,2.28571-31.9183i,-180    (M1)
May 12: p:0,0  z:2.28571+47i,2.28571-47i,-600              (M2)

The 1st attached plot shows these two measurements, overplayed with the models M1 and M2.
The 2nd plot shows the 4 raw measurements (2 yesterday, 2 today).

We didn't try to engage this SRCL FF yet.

Sheila, Stefan,

We noticed the H1:ALS-X_TR_A_LF_OUT signal (Xarm green transmission) drop to zero with the cavity aligned without good reason. The first time this happened, the signal came back after a few minutes. One lock-loss later the same thing happened, and didn't come back.

We went to ISCT1, and as soon as we touched the BNC cable of the x arm Green transmission photo diode, the signal jumped back.

We replaced the T that was in between the PD and the BNC cable with an L. The T was removed from circulation.

Both the bounce and roll mode were rung up on ITMY.

Roll: freq 13.934Hz damped using AS WFS, a gain of -100dB, bandpass 13.9Hz, and a negative gain around 1.  This was done at a CARM offset of 10 pm since the IFO wasn't stable if we tried to go on resonance.

Designed new filters for compensating the ITM PUM->TST P2P and Y2Y drive path.

- There filters were originally designed starting with Jeff's suspension model. They were then tested and fine-tuned using an optical lever feed-back.
- They include inversions of the two suspension poles - slightly offset in frequency to guarantee stability.
- They also have a notch to kill a rung-up suspension modes a 3.1Hz and 3.3Hz. That will prevent high BW feed-back, but that's currently not planed for the ITMs.
  (I rang up the 3.31Hz mode in ITMX PIT, and thus copied that everywhere. ITMY YAW I actually rung up 3.12Hz, so I moved the notch for that one.)
- They were gain-matched to the old filters at low frequencies.

- The filters were installed in FM10 of the ASC filter banks for DSOFT and CSOFT (see below). They should replace the old lead filters in FM2.

DSOFT_P (ITMX_PIT):
zpk([0.034375+i*0.548925;0.034375-i*0.548925;0.0700002+i*1.39825;0.0700002-i*1.39825],
    [6.52535+i*17.507;6.52535-i*17.507;7.32113+i*15.9155;7.32113-i*15.9155],0.236209,"n")
 notch(3.311,30,20)
gain(12.044,"dB")

DSOFT_Y (ITMX_YAW):
 zpk([0.035625+i*0.568886;0.035625-i*0.568886;0.0650001+i*1.29837;0.0650001-i*1.29837],
    [6.52535+i*17.507;6.52535-i*17.507;7.32113+i*15.9155;7.32113-i*15.9155],0.236209,"n")
 notch(3.311,30,20)
gain(13.06,"dB")

CSOFT_P (ITMY_PIT):
 zpk([0.034375+i*0.548925;0.034375-i*0.548925;0.0700002+i*1.39825;0.0700002-i*1.39825],
    [6.52535+i*17.507;6.52535-i*17.507;7.32113+i*15.9155;7.32113-i*15.9155],0.236209,"n")
notch(3.311,30,20)
gain(12.044,"dB")

CSOFT_Y (ITMY_YAW):
 zpk([0.034375+i*0.548925;0.034375-i*0.548925;0.067+i*1.33832;0.067-i*1.33832],
    [6.52535+i*17.507;6.52535-i*17.507;7.32113+i*15.9155;7.32113-i*15.9155],0.236209,"n")
notch(3.12,20,30)
gain(13.06,"dB")



Attached is a plot of old vs new TF for ITMY YAW.

Jeff, Evan, Kiwamu,

We changed the delay cycle between the actuation and sensing paths from 4 cycles to 1 cycle in CAL-CS in this evening at around May-12-2015 1:00 UTC. This is going to more correctly reshape the DARM spectrum at around the UGF.

According to the model that Jeff has been working, the expected time delay between the two paths is 40.1 usec which is about 0.657 cycles for a 16 kHz frontend model. This has been consistent with the measured DARM open loop within a phase error of 1 or 2 degrees. Since the CAL-CS accepts only an integer mupltile for the delay cycle, we put 1. Historyically, the previous factor of 4 came from Livingston when we copied their calibration setup (llo 16475).

For more details, see H1DARMmodel_preER7.m in CalSVN/aligocalibration/trunk/Runs/PreER7/H1/Scripts.

Nutsinee, Elli

Both CO2 lasers tripped, about 10 minutes from each other, the H1:TCS-ITMX_CO2_INTRLK_RTD_OR_IR_ALRM had tripped, due to Filberto's working near Ham4 (the temperature sensor which will eventually be attached to the viewport is currently on the electronics rack next to the CO2 laser tables and is sensitive to people working near it.  CO2 X power on the IMTX has been returned to 0.22W. 

HWS X was working.  Then we touched the picomotors on the periscope mirrors and lost the alignment due to hysteresis. Dang.  HWSY SLED is aligned to irisis, green beam still clipping somewhere.

We have decided to leave EY HWS plugged into its separate power supply for the time being.

See D1400363 for overall scheme and cable details.

The 71 MHz sine is ported to D1400155 in TCS-X1-R2-27 SE of BSC1.  From there sync signals go to the three BSCs corners 1 & 3 satellite racks.  At each BSC, the corner 1 signal is passed on to corner 2 with a local cable.

Attached are three plots with the three BSCs showing reference traces from early this morning before the big EQ.  Current traces are from later today.  There are no combs popping up suggesting there are no cross talking sync signals.  There is variablilty between the reference and current noise floors.  Some are lower a few are slightly higher but nothing standing out affecting an entire corner (see ITMX ST2 H2.)  I suspect when the middle of the night comparison is done with similar conditions, they will look even better and that cables are okay.

SudarshanK, DarkhanT

We introduced two Pcal lines at 240 Hz and 310 Hz on photon calibrator at Y end.  The Pcal lines are about a factor of 10 above the DARM sensitivity at those frequencies. We will look into any changes in the amplitude and phase of these lines to determine the the position of cavity pole frequency. The cavity-pole has been observed at frequencies listed in  alog LHO #18360.