Per the weekly Tues Maintenance task, the chiller was topped off to the MAX level mark (needed ~250ml to do this).  The stopper for the Chiller isn't ideal (seems a bit big and sheds a bit to make it seat in the inlet).  Last time the chiller was filled was on 9/15/14.

I measured the beam pointing sensitivity of all the eight ISS second loop diodes. The naming is the one corresponding to the new slow channel acquisition, we'll check tomorrow the correspondence to the PD1-8 signals. For some diodes, in pitch, I was not able to see any significant modulation

For those not familiar with the meaning of these numbers, the typical values measured for the ISS array before installation were between 1 and 30, depending on the array and on the diode. So the numbers I got are in general quite large.

This beam position on the PD is maybe not the best one, since we are not at the maximum power for all the diodes simultaneously. For each diode, it is possibile to find a beam position that gives maximum power. This also corresponds to undetectable coupling of beam motion to dP/P (at least at this level of excitation). However, the good position is different for each diode, and the non optimal one can have a significant loss of power and large coupling of beam motion to dP/P. The table above is representative of what we normally get.

Here is the procedure in details

1. Move the beam using the picomotors to center the QPD. Dither IM3 with an amplitude of 100 counts at 1 Hz in both pitch and yaw (H1:SUS-IM3_M1_OPTICALIGN_P_EXC and H1:SUS-IM3_M1_OPTICALIGN_Y_EXC), and measure the normalized signal on the QPD. I got 0.14 peak to peak in pitch and 0.22 peak to peak in yaw. The beam size on the QPD should be 250 um. The normalized signal should be given by sqrt(8/pi) * deltaX / w where deltaX is the beam motion on the QPD and w is the beam size. Therefore, 100 cts at 1 Hz of IM3 correspond to 22 um in pitch and 35 um in yaw of beam motion on the QPD. I assume that the motion on the photodiode is the same. 
2. With the dither on, I measured the mean value of each of the photodiode and the peak to peak oscillation at the dither frequency, separately in pitch and yaw. I had to move pitch of 300 counts (70 um beam motion on the diodes) and yaw of 100 counts (35 um of beam motion on the diodes). Larger amplitudes were giving weird signals.
3. From the photodiode signals I computed the dP/P and then the dP/P/x reported above

Comparable to other Level3s.

Weekly report of various things.

There are daily spikes in the H1 chiller and diode room relative humidity.  The spikes also occur in the chiller room temperature but not in the diode room,
or at least the ones in the diode room are not as large.

Relative power noise looks nominal.  Better than the reference measurement below 10 Hz and a factor of a few worse between 10 Hz and 4 kHz.  The ISS was locked at the time with a diffracted power of ~9%, REFSIGNAL -2.03 V, and output DC of 10.01 V on PDA, 10.19 V on PDB.  Gain slider on 10 dB.

Frequency noise is better than the reference measurement above ~500 Hz, worse below.  Otherwise the same as per previous weeks.

Beam pointing looks nominal.  All better than the reference measurement.

Mode scan looks nominal.  Higher order mode count slightly higher than last week, 55 cf. 56.  Higher order mode power slightly higher too, 4.7% cf. 4.6%.  Nothing to worry about.

ISS relative power noise looks good.  The out of loop measurement (PDB) is flat from 3 Hz to ~100 Hz, at ~1.3E-8.  Rising to ~2E-8 at 1 kHz.

no restarts reported

Kiwamu, Jenne, Alexa, Sheila, Daniel,

Today we locked ALS COMM.  We chaanged the locking sequence compared to our old sequence.  One difference is that we have moved the notches in MC2 to M2, so we can have a higher crossover between the slow and fast actuators (CARM gain is 240 now, instead of 80).  We also got rid of a z5 p20 filter we had in the CARM filter module.  The rest is the same as it was in late May.  This seems to be locking fairly robustly.  The ugf is 1 kHz, with a phase of -80 deg.  A measurement of the cross over is attached.

We also aligned the DIFF beatnote, 800mVpp.  We have locked this at low gain a few times.  We need to feedback to the top mass of the ETMs to keep the DIFF PLL within the VCO range, but we have had trouble engaging the tidal feed back.

[Jim, Fabrice]

To help comparing and finding the best of the blend configurations used at each sites, we loaded the LLO blend configuration on ITMY.  Unlike for previous transfers of filters from site to site, we did not export the filters from LLO foton files into different continuous or digital forms before to re-convert them, simplify and re-install them into LHO foton file. We directly copied and pasted the second order sections from one foton file to another. [We used the filter file logged in the repository Keith has set up (very useful!): https://daqsvn.ligo-la.caltech.edu/websvn/]. A few blend filters take two banks,  we left it that way.

We performed measurements with the initial configurations (called "before" in the figures) and with the LLO filters configuration (called "after" in the figures). The blend configurations are summarized at the end of the report.

- The first two figures show the ISI motion for each configuration. Using the LLO config (after), the X and Y motion is lower at the suspension resonances at the cost of more motion at higher frequencies (good compromise). The rotational motions appear higher at most frequencies.

- The next two figures show the suspension point motion for each configuration. In the initial configuration, the suspension point motion is dominated by ISI longitudinal motion at almost all frequencies. With the LLO blend, the RZ motion takes over around 1 Hz.

- The last two figures show the optical lever motion for each configuration. In this example the Pitch RMS motion went from 5.8 nRad (before) to 4.1 nRad (after).  The Yaw RMS motion went from 6.6 nRad to 4.2 nRad. [These numbers seem very small (calibration issue?) but the relative comparison is probably fair.] 

We leave it on for tonight for making a comparison over a longer stretch of time.

---------------

Blend configuration used for the "before"  and 'after" measurements.

DOF:            Before  /  After

Stage 1 X : Tbetter  / 45mHz

Stage 1 Y: Tbetter / 45mHz

Stage 1 RZ: TCrappy / Off

Stage 1 Z: T750mHz / 90mHz

Stage 1 RX: Tbetter  / [250a & 250b for CPS and T240, 250 for L4C]

Stage 1 RY: Tbetter  / [250a & 250b for CPS and T240, 250 for L4C]

Stage 2 X : T750mHz  / 250 mHz

Stage 2 Y: T750mHz  / 250 mHz

Stage 2 RZ: T750mHz / Off

Stage 2 Z: T750mHz / Off

Stage 2 RX: T750mHz / Off

Stage 2 RY: T750mHz / Off

After finding good whitening setting, the arm was aligned, I walked the beam on WFSB to find a good offset.

Demod phase was set after finding a good position on WFSB (PIT offset = -0.15, YAW=0). For WFSA I never set any offset.

See the first attachment for the demod phase.

See the second for the spectra after an offset of -0.15 was set for the WFSB PIT centering servo to balance the demod signal peak generated by an excitation to the PDH board EXC A.

Sudarshan, Gabriele

We significantly improved the beam centering on the ISS array: now we have good powers on all diodes, centered QPD and lower coupling of beam motion to dP/P

The procedure

1. We wrote a python script that uses the picomotor 1 to maintain the beam centered on the QPD. 
2. We moved picomotor 8, mainly in the LEFT direction. After each motion, we ran the script to recenter the beam on the QPD. We then checked that we were improving the power levels.

After a lot of steps in the LEFT direction and few in the UP direction (for picomotor 8), we could get the beam centered on the QPD and good power levels on all diodes. Actually, we believe we are quite close to the maximum power for each diode.

The results

The following table compares the power levels (in counts) before our adjustment and at the end.

Then, we measured again the coupling of beam motion to dP/P, and we got much improved numbers:

At this level it is difficult to find a better position looking only at the power levels. We might have to optmize the centering looking directly at the beam motion coupling.

Summary:

Some whitening settings for EY green WFSA  I3, Q3 and WFSB Q2 channel don't work. It's probably the whitening chassis itself as the whitening request and the readback agree with each other.

For now I'm leaving both of the chassis in place as there are some usable settings, but note that these guys have a history of many troubles due to chassis and crappy cablings (12159,  12138, 12127).

Details 1:

For WFSA I3 and WFSB Q2, the measured whitening gain doesn't match the request and the readback (attached).

You can see that in both cases one of four stages (+3dB, +6dB, +12dB and +24dB) is failing. It's the 12dB gain stage for WFSA I3 and the 6dB stage for WFSB Q2.

These were measured injecting 20mVpp signal at 100Hz using a function generator and a breakout board.

Details 2:

For WFSA Q3, the third whitening filter doesn't turn on.

For now:

I set the gain to +27dB and turned all filters off.

Alastair & Greg

Greg is running the TCS x-arm laser for a couple of hours (from 16:41 onwards) so we can start to get some data on stability at LHO.  The beam to the CP is blocked so there is no output, and the laser is being run with the table closed.

Performance plots later.  Lvl2 will be quick but later too.

9:20 am Jeff B and Andres R to X-End lab area, retrive 3-IFO TMS components.
9:35 am Danny S to CS VEA, West bay area, quad work.
12:58 pm Karen to Y-end VEA, cleaning.
FIRE DRILL.
1:25 pm Danny S to CS VEA, West bay area, quad work.
1:28 pm Richard M and Patrick T from CS control room, Beckhoff work.
1:30 pm Jeff B and Andres R to Y-End.
1:45 pm Rick S and Peter K to CS VEA, pull cables from CER to HAM2 area.
3:14 pm Danny S to CS VEA, West bay area, quad work.
3:29 pm Travis S to CS VEA, west bay area, quad work.
4:06 pm Greg G to CS VEA, TCS work.
4:12 pm John W and Bubba G to Y-End VEA, walk/inspection.

PSL Check: 9/29/2014

Laser Status:

• SysStat is good
• Output power is 33.6 W (should be around 30 W)
• FRONTEND WATCH is active
• HPO has multiple red, LOCKED, LRA, WATCH and WARNINGS.

PMC:

• It has been locked 2 days, 20 hr , and 56 minutes (should be days/weeks)
• Reflected power is 2.0 Watts and PowerSum = 25.6 Watts.
• (Reflected Power should be <= 10% of PowerSum)

FSS:

• It has been locked for 1 min (should be days/weeks), keeps glitching.
• Threshold on transmitted photo-detector PD = 1.753 V (should be at least 0.9V)

ISS:

• The diffracted power is around 9.75 % (should be 5-15%)
• Second loop is RED.
• Last saturation event was 1 d, 23 h and 20 minutes ago (should be days/weeks)

Now with added "damped" plots.  Note, the damping loops on the electronics test stand are hodge podge and so damping was poor for some regions of many loops.  As well, like I mentioned in earlier logs, the coherence of this in-air QUAD is poor at lower frequencies.  I spent some time trying to work out better excitation filtering/boosting but to no avail.  Damping works on both M0 and R0 chains of Q6.

This morning I adjusted the x-arm alignment to obtain green locking. First I misaligned ETMX, and adjusted TMSX using the ITMX baffle PDs. See table below for configuration:

NOTE: he baffle PDs read 2.4V at 0dB gain.

Then, using the ETMX camera I centered the beam on ETMX by adjusting the ITMX alignment. I found ITMX (P,Y) = (74.7, -8.2). Finally, I maximized the flashes by aligning ETMX. H1:ALS-X-TR_A_LF_OUT reached about 0.85 cnts. With this alignment we were able to lock the green beam to the arm. The alignments are saved to the guardian.