At 5:20am local time we saw a significant range drop (from about 70Mpc to 60Mpc) that seems to be due to a signicant increase of the line structure in the bucket that always lingers around the noise floor.

Attached are two spectra - 1h12min apart (from 11:18:00 and 12:20:00 UTC on 2016/10/24), showing that structure clearly.

Plot two shows the seismic BLRMS from the three LEAs - the corner shows the clearest increase. We are now chasing any particularly bad correlations around 12:20 thgis morning in the hope that it will give us a hint where this scatter is from.

Laser Status:
SysStat is good
Front End power is 34.7078746276W (should be around 30 W)
Frontend Watch is GREEN
HPO Watch is GREEN

PMC:
It has been locked 2.0 days, 13.0 hr 31.0 minutes (should be days/weeks)
Reflected power is 30.1950603235 Watts and PowerSum = 138.878561539 Watts.

FSS:
It has been locked for 0.0 days 12.0 h and 16.0 min (should be days/weeks)
TPD[V] = 3.53977605389V (min 0.9V)

ISS:
The diffracted power is around 1.43660487293% (should be 5-9%)
Last saturation event was 0.0 days 12.0 hours and 16.0 minutes ago (should be days/weeks)


Possible Issues:
(Be sure to look into these, as they will not be printed in the report)
PMC reflected power is high
ISS diffracted power is Low
 

Nothing out of the ordinary.

Tuesday will be TIGHT,LIMITED maintenance.

SUS- FE changes for tomorrow. Charge measurements.

SEI- Everything seems to be running fine. Tomorrow - Quarterly check of HEPI fluid pressure accumulation.

PSL- Today - picomotor installation for remote aligning of PMC

CDS - (Electronics) HWS camera power, BIO repairs

           (Software) Investigationsinto disk space issues

VAC- scroll compressor maintenance at EX. RGA bake will be a couple more days.

FAC- Fan lubing

COMMISH- Timing measurements at end stations.

Attached are oplev trends (thus closing FAMIS #4698).

NOTEs:

• BS has values beyond -10 (pit at -12 & yaw at -15)
• ITMy yaw is approaching -10.
• Nothing blaringly obvious with the SUMs.

J. Kissel for S. Karki

I've moved the roaming high frequency calibration line driven by PCAL X from 2001.3 to 1501.3 Hz at Oct 24 2016 15:26:57 UTC (1161358034, 08:26:57 PDT).

Here's the status: 
Frequency    Planned Amplitude        Planned Duration      Actual Amplitude    Start Time                 Stop Time                    Achieved Duration
(Hz)         (ct)                     (hh:mm)                   (ct)               (UTC)                    (UTC)                         (hh:mm)
---------------------------------------------------------------------------------------------------------------------------------------------------------
1001.3       35k                      02:00      
1501.3       35k                      02:00                   39322.0           Oct 24 2016 15:26:57 UTC
2001.3       35k                      02:00                   39322.0           Oct 17 2016 21:22:03 UTC    Oct 24 2016 15:26:57 UTC      several days (at both 50W and 25 W)
2501.3       35k                      05:00                   39322.0           Oct 12 2016 03:20:41 UTC    Oct 17 2016 21:22:03 UTC      days     @ 50 W
3001.3       35k                      05:00                   39322.0           Oct 06 2016 18:39:26 UTC    Oct 12 2016 03:20:41 UTC      days     @ 50 W
3501.3       35k                      05:00                   39322.0           Jul 06 2016 18:56:13 UTC    Oct 06 2016 18:39:26 UTC      months   @ 50 W
4001.3       40k                      10:00
4301.3       40k                      10:00       
4501.3       40k                      10:00
4801.3       40k                      10:00  
5001.3       40k                      10:00

Ops Shift Log: 10/24/2016, Owl Shift 07:00 – 15:00 (00:00 - 08:00) Time -  UTC (PT)
State of H1: IFO is locked at 26.9W, with 69.6MPc.
Intent Bit: Observing
Wind: Gentle to Moderate Breeze (8-18mph)
0.03 – 0.1Hz: EY at 0.01um/s, EX at 0.07um/s, CS at 0.09um/s
0.1 – 0.3Hz: All around 0.3um/s
Outgoing Operator: Nutsinee
Incoming Operator: Ed
 
Activity Log: Time - UTC (PT)
07:00 (00:00) Take over from Nutsinee
08:55 (01:55) PI Mode-18 ringing up. Changed Phase from -100 to -350 to suppress the ring up
09:00 (02:00) PI Mode-28 ringing up. Changes Phase from 60 to -80 to suppress the ring up
11:13 (04:13) PI Mode-18 ringing up. Changed Phase from -350 to -200 to suppress the ring up
15:00 (08:00) Turn over to Ed


Shift Details:
Support: Sheila (by phone)
Shift Summary: IFO locked in NOMINAL_LOW_NOISE	 for the past 2 hours. All appears normal. PI Mode-18 started to ring up. Changed Phase from -100 to -350 to suppress it. Mode-28 is elevated bit still below 1. Changes it’s phase from 60 to -80 to suppress the ring up.  
IFO has been locked in Observing mode all shift. Environmental conditions are good. The wind has dropped off to near zero and microseism is low. The 0.1-0.3 band has been ringing up for the past two hours, but is still below 0.5um/s.  

Attached is the voltage noise spectrum of the Kepco BHK 500-0.4MG power supply that provides the high
voltage for the pre-modecleaner and injection locking.

    I need to check with Marc to see what the voltage monitor divider ratio was.

TITLE: 10/23 Eve Shift: 23:00-07:00 UTC (16:00-00:00 PST), all times posted in UTC
STATE of H1: Observing
INCOMING OPERATOR: Jeff B.
SHIFT SUMMARY: Commissioning most of the evening. We were down for a bit due to an earthquake. No problem locking tonight. Intent bit has been set.

LOG:

2:41 Daniel and Stefan going to end stations to bang on the beam tube

~3:50 Daniel, Stefan back.

6:36 Intent bit set. Enjoy the data!

Sheila, Terra

We changed the bias on ETMX and watched the 60Hz and 120 Hz lines in DARM. The 60 Hz line was reduced by 50% by switching from +400V to -400V, which the 120Hz line was reduced by almost a factor of 2.  Apparent changes in other parts of the spectrum weren't reproducible. 

We set it back to +400V

Daniel, Stefan,

With the interferometer in a decent noise state at 25W, we went to both end stations with a calibrated rubber mallot (actually a shovel a rubber cover on the handle).

We first shuttered the PCAL lasers because we didn't want to short-circuit scatter measurments.

Upon banging the vacuum vessel the noise increased in a fairly broadband manner. On top of that some individual beaks at ~90Hz and ~110Hz also were rung up.

The worst spot in both end stations was the periscope supporting PCAL and camera. ETMX seemed to be slightly more sensitive.

Attached is a reference spectrum showing the sensitivity when we did the injections, including references from the best H1 the recent best L1.

POP_A_RF9_I to SRCL matrix element is no -0.025. This cleaned up at least the SRCL error point a little. THe change is in the guardian.

We've been locked at 26 Watts looking at low frequency noise, so just to make things easier I cut the HARD pit loops off a little bit lower. 

I lowered the gain of DHARD P from 30 to 20, I lowered CHARD P from -0.15 to -0.14.  I replaces the JLP25 filters with second order elipticals at 10 Hz.  I put this in the guardian to happen when we are locked below 45 Watts.

This helps DARM from about 15-27 Hz.  In the attached screenshot you can see how DARM and the coherences changed. 

In the past few weeks and months it has been becoming increasingly clear that we are limited by beam jitter when going to higher power. The beam jitter requirements were derived assuming an rms misalignment of the test masses of 10^-9 rad rms in units of divergence angle or beam radius; see T0900142. The coupling mechanism is through the symmetric alignment matrix which mixes TEM₀₀ and TEM₁₀ modes. This transforms jitter in the first order mode back to zeroth order where it beats against the carrier field to produce an intensity fluctuation. This mechanism is independent of the OMC, since the intensity noise is generated in the interferometer. The jitter requirement into the input mode cleaner is:

We can compare this with the measurement from alog 30237 in the attached pdf. The solid olive curve represents the requirement which is a factor of 10 below the level (dashed olive line) one would expect the noise to be visible in the gravitational wave readout at full power and assuming a 10^-9 rms misalignment.

The following observations can be made:

• Even during O1 we have observed the periscope peak to be a factor of a few above the noise level. This would indicate the the assumption of a 10^-9 rms misalignment is about right for a cold interferometer. Keep in mind that the rms includes any static offset errors.
• In the current laser configuration (HPO on with ~5 l/m cooling flow) we are above the requirement for all frequencies between 50 Hz and ~1 kHz; typically by a factor of a few and a factor of ~40 in the worst case.
• The first order jitter out of the HPO meets the requirements. We would need a close to 2 orders of magnitude larger coupling to see the HPO jitter around 500 Hz.
• At high power with thermal loading the coupling typically gets worse—presumably because of higher order modes introducing a larger misalignment.
• It is basically impossible to explain the observed jitter coupling from the HPO using the exact same mechanism.

Possible alternative explanations to the visible HPO jitter in the gravitational wave readout at 50 W input:

• An unlikely Gouy phase conspiracy where the jitter after the PMC couples much weaker than the HPO jitter. In principle, the rms misalignment angle and spot position could be far different from each other. However, this would require two orders of magnitude difference and a required Gouy phase accuracy of ~1°.
• The HPO might also generate second order jitter at the TEM₂₀, TEM₁₁ and TEM₀₂ modes. This second order jitter would couple with arm cavity curvature and beam size mismatch back into the zeroth order mode. Under thermal load it is unlikely that we have a match at the 10^-9 level of beam size and curvature. It could be 100 times larger easily.
• Some other unknown mechanism—even so direct coupling through intensity noise, frequency noise or error point offset in the reflection port have essentially been ruled out.

16:44 Begin bringing back IFO from computer crash.

17:06 Begin aligning/locking process

17:48 on the hone with Dave Barker about a ALS_XARM guardian node I was having trouble restarting. Ezca connection error to H1:ALS-X_WFS_SWITCH channel

22:00 Damping ITMY bounce mode. Flipped sign on gain and added .1 gain

22:40 damped PI mode 27 by flipping the sign and then adding 30 degrees to the phase.

22:58 PI Mode 27 needed another sign flip

22:47 NLN ≈60MPc. Handing off to Nutsinee

Plot 1 shows the DC signals of all 4 I segments of ASA36. Note that seg 3 is ~2.5 times larger than the others.

Plot 2 shows the updated AS_A_RF36_I matrix - the gains for seg 3 have been dropped to -0.4 from -1.

Plot 3 shows the resulting error signal - it now cresses zero where the buildups and couplings for SRCL are good.

Closed the SRC1 PIT and YAW loops with a gain of 10, and input matrix element of 1. I will leave this setting for the night - although it is not in guardian yet.

Keita, Sheila, Kiwamu

This afternoon Keita and I did another test of opening and closing DBB shutters, since Keita realized that there are multiple shutters that matter.  The results are in the screen shot.  We only see two shutters on the PSL layout, (SH01 in the 35 W path to the DBB and SH02 in the 200W path) and on the photos documenting the table, but there must be a third shutter, perhaps inside the DBB box. We did not test switching to the 35W beam because that caused a lockloss last night. Apparently the shutters used here are Thorlabs SH05, which has an aluminum blade according the the thorlabs website. 

When changing between shutter states today we saw a broad band change in the DARM noise throughout our 200Hz-1kHz lump, (this is a little different from what we saw last night).  However, we saw 3 different noise states in DARM depending on the shutter requests, shown in the attachment.  

We guess that the shutter which is controlled by the epics channel "PSL-DBB_SHUTTER_DBB" is inside the DBB box itself and not on the layout.  It is hard to explain the table above.  For example, if no beam is selected, and both beams are really blocked before they reach the DBB, why would closing the shutter inside the DBB matter?  

Kiwmau and I went inside the PSL, placed beam dumps in the paths to the DBB.  We placed a "black hole" beam dump (no cone in the middle) in the HPO path (a 250 mW beam between M3 and M12 on the layout).  Looking at that beam with an IR card, we could see a corona around it, pictures will be attached to this alog.  This corona is scattered around, hitting the black baffle near the DBB apperature and other things.  We also placed a black glass beam dump upstream of the front end laser beam path the the DBB, just before the shutter. 

Update:

After waiting out the Japanese earthquake, we relocked.  The lump was smaller in the first moments of the lock.  After a few minutes the peaks reappeared, but the peaks still changed when we opened and closed the shutters, in a way that is repeatable although the plot is confusing since the overall level of noise was changing probably with the thermal state.  (each time we opened the shutter, things got worse than they had been).

We do not understand how changing the shutter state impacts the DARM noise, although we think we have ruled out scattered light.   Kiwamu thought that perhaps the change in the noise could be due to the change in the diffracted power when we move the shutter (see Keita's alog 30679). We tried a test of changing the diffracted power, which unlocked the IFO.  It could also be through the same electrical coupling that means the diffracted power changes when we open the shutter.