Each main turbo pump (MTP) has an adjoining box containing (4) ea. 12v 18Ah sealed lead acid (SLA) batteries connected in series that provide 48VDC for pump rotor levitation during loss of AC power.  These only get charged when the turbo controllers are energized.  As preventative maintenance during the prolonged periods of pump inactivity, we would energize the controllers for a few hours during Tuesday's maintenance period.  We now will keep these battery packs centrally located (hallway between AHU1 and AHU2 in the Corner Station Fan room) and on a battery tender.  The trade off is that we now will need to remember to take a battery pack with us when activating an MTP at an outbuilding.  

This morning, Chandra and I weighed an empty BSC LTS container. After weighing that container, we decided to check the weight on a loaded BSC LTS container. The loaded container never lifted off the floor. The crane capacity is only 10,000 lbs. and another 380 lbs. would not have lifted the container.   The results are in the photos here. 

(Kyle, Gerardo)

Today compressors #3, #4, and #5 were all greased and pressure tested.

All compressors passed their compression test, #3 at 120 psi, #4 at 120 psi, and #5 at 130 psi.
Then all compressors and electrical motors were greased.

All compressor assemblies were run tested after service was performed.

Work performed under WP#6257.

(See WPs #6221 and #6255)

Will need to make daily check each morning.  Plan to run through 10/23 inclusive unless too egregious for commissioners

M. Pirello

This FPGA code ( E1200034 ) disconnects the 1pps signal from the 4 internal LED's and grounds them.  All four timing comparators at LHO were updated to v5.

S1107952 in the CER

S1201224 in the MSR

S1201886 at X end

S1201222 at Y end

Work Permit 6256

Work Permit Number: 6252

The DMT calibration has been updated to gstlal-calibration 1.0.6-2.el7. Because of dependencies GDS was also updated to: gds-2.17.10-2.

John Zweizig has restarted the DMT monitors.
 

The medm SYS_CUST_SHUTTER_SUMMARY.adl shows the ALS shutters, but the names are wrong.  Attached is a map of what each shutter did today.

DCS verified all H1_R frames were copied from the CDS "science" directories into the LDAS archive up to the GPS endTime 1160847040.

LDAS has started copying the new larger H1_R frames from the CDS "full" directories, with the first larger H1_R frame with the "full" channel list starting from 1160854656.

Hiro asked me about LHO BRDF measurements like LLO (https://alog.ligo-la.caltech.edu/aLOG/index.php?callRep=28662).

Using numbers measured by Vinny (https://dcc.ligo.org/T1600085) when the arm power was about 100kW back in January, the corresponding BRDF numbers are:

There's no evidence that this changes with power: alog 28449

I ran a BruCo scan of last night's lock (GPS 1160787977 + 600s). The full report is available here. As pointed out by Sheila et al, the low frequency region (below 100 Hz) doesn't show much coherence with anything (low coherence with MICH/SRCL, fig 1 and 2, a bit with angular controls, fig 3 and 4, but lower than usual.)

In the jitter region, there are the usual coherences with IMC WFS and signals. However, I found interesting coherences with a few more channels in this region

• coherence is quite high on the peaks with PSL-ISS_PDB_REL_OUT (fig 5), while there is a kind of broadband lower floor of coherence with PSL-ISS_PDA (fig 6)
• coherence similar to PDB is present with PSL-ISS_AOM_DRIVER_MON_OUT (fig 7)
• high coherence also with LSC-REFL_SERVO_CTRL_OUT (fig 8) and related error signals (LSC-REFL_A_I/Q_ERR, not that there is coherence with both I and Q, although lower in Q, figs 9 and 10)
• also there is coherence, at similar levels, with the PMC control: PSL-PMC_HV_MON_OUT (fig 11)

I'm not sure what to make of all those coherences, since coupling through intensity or frequency noises were almost ruled out...

Finally, the DBB channels are not available in the science frames that are read by BruCo, so I separately computed the coherence with the DBB QPDs. Figure 12 shows the usual coherence with the DBB_QPD_1QY signal.

Jenne and Sheila concluded that the noise in the auxiliary length loops was keeping the IFO from locking on DRMI and had me set it to down for the night.

07:15 UTC Paused at PRMI_LOCKED for Jenne and Sheila
07:43 UTC Set to down for Jenne
07:45 UTC Starting initial alignment
08:24 UTC Initial alignment done
09:24 UTC Set ISC_LOCK guardian node to DOWN for the night
13:42 UTC Peter to H2 PSL enclosure and transitioning LVEA to laser safe
13:56 UTC Peter done
14:09 UTC Bubba to LVEA (WP 6254)
14:30 UTC Portable toilet service through gate

Peter has transitioned the LVEA to laser safe.

We're really struggling to acquire DRMI lock. It looks like our aux length loops suddenly have way more noise than they did before our last long lock stretch.  We're not at all sure why this is, but may want to look into it more, in case it hints at why we have more noise in the aux loops now than we did before we did the grouting / realignment in April. We can lock PRMI, but it is very noisy, and if we try to improve the buildups the noise gets worse.

We had a nice long lock, but then struggled to relock.  Nutsinee did an initial alignment, during which we decided to move IM2 and IM3 closer to their nominal positions, in acknowledgement of the warnings that have been on DiagMain lately.  However, we still couldn't aquire lock, so started to look at the noise.

Sheila and I found a time from earlier today (17Oct2016 16:03:00 UTC) where we were locked on PRMI for a few minutes, and saw that the MICH and PRCL noise was quite good.  In the attached screenshot that time is labeled "10+ hours ago".  When we first caught the PRMI, we had noise that looked like the "really bad" time in the screenshot.  This is more than 2 orders of magnitude worse than the quiet time for MICH between 10Hz-200Hz.  For PRCL the noise is only worse below about 150Hz, but it is still egregious.  By moving the alignment of the recycling cavity mirrors and the input steering mirrors, we could reduce the noise to the third set of traces, at the cost of losing at least a third or so of our sideband buildup. 

Thinking that this could be somehow related to our restoration of the IM2 and IM3 positions, we restored all suspensions (except RMs and OMs) to their witness or oplev values from 14 hours ago.  Patrick then did a careful initial alignment, but unfortunately our noise is still the same.  We can acquire PRMI but not DRMI.  At this point we're going to leave things as-is for now, and look into it again tomorrow after maintenence. 

We wonder though if this is a clue as to how / why we have so much extra noise in our aux length loops since April.

Looking at the coupling of carrier jitter with misaligned RF sidebands in REFL:

Jitter (alog 30237): 10^-6/√Hz (level) to n x 10^-4/√Hz (peaks)
IMC suppression (alog 30124): ~¹⁄200
⇒ at IFO: 5 x 10^-9/√Hz to ⁿ⁄2 x 10^-6/√Hz

Fixed misalignment of RF sidebands: Δα < 0.3
DC power in reflection with unlocked ifo at 50W: REFL_DC^unlocked ~ 300 mW
Error offset in REFL = jitter * REFL_DC^unlocked * Δα
⇒ 5 x 10^-9/√Hz  * 0.3 W * 0.1 ~ 1.5 x 10^-10 W/√Hz (low)
⇒ ⁿ⁄2 x 10^-6/√Hz * 0.3 W * 0.3 ~ ⁿ⁄2 x 10^-7/√Hz (high)

Frequency noise coupling into DARM (alog 29893):
⇒10^-10 m/W at 1kHz (approx. f-slope)

at 1kHz: 10^-20 m to 10^-17 m
at 300 Hz: n x 10^-18 m (high) with periscope peak n ~ 4.

Summary

Daniel points out that the behavior of REFL LF during the 9 MHz modulation depth reduction does not make sense:

• The measurement implies that during lock acquisition, at 50 W of PSL power there is 0.76 mW of 9 MHz light on the REFL diode.
• On the other hand, assuming a 9 MHz modulation depth of 0.22 rad, and a splitting ratio of 0.0066 W/W for the diode, and assuming 100% of the 9 MHz light is reflected out of the interferometer, we should instead expect 8.0 mW of 9 MHz light on the REFL diode.
• Additionally, AS_C sum indicates that we have about 100 mW of 9 MHz light leaking out the dark port at 50 W of PSL power, compared to 1.2 W of 9 MHz light being sent into the interferometer (assuming 0.22 rad of modulation depth). So we are not losing a significant amount of 9 MHz light through the dark port.

One possible explanation is that the 9 MHz depth is a factor of 3 lower than we think it is. However, based on single-bounce OMC tests (described below), this seems to not be the case. So the discrepancy remains unexplained.

Details

For the OMC test, I first turned up the modulation depth by 3 dB (the slider value is normally 16.8 dB during lock acquisition, so I turned it to 19.8 dB).

Then I locked the OMC on the carrier, and then each of the 9 MHz sidebands, and recorded the following data:

I assign an uncertainty of 10% to the OMCR and OMC trans sum values. The OMC visibility is not perfect here, but we can nonetheless roughly infer the modulation index. If the carrier measurement had been done at 47 W, we would have seen 70.6 mA of sum photocurrent. Since Psb/Pc ≈ Γ²/4, this implies Γ = 0.25 rad during this measurement. This implies a value of Γ = 0.17 rad during normal lock acquisition. This is within 30% of the old value measured with the PSL OSA (0.22 rad). In other words, we are not missing a factor of 3 in the modulation depth, so the behavior of REFL LF during lock acquisition does not make sense.

J. Kissel, D. MacLeod

Duncan had noticed that Omicron triggers for the H1 PCAL Y RX PD (H1:CAL-PCALY_RX_PD_OUT_DQ) had failed on Oct 13 02:51 UTC (Oct 12 18:51 PDT) because it was receiving too many triggers. 

Worried that it might have been a result of the recent changes in calibration line amplitudes (LHO aLOG 30476) or the restoration of the 1083.7 kHz line (LHO aLOG 30499), I've trended the output of the optical follower servo, making sure that it has not saturated, and/or is not constantly glitching.

Attached is a 3 day and 30 day trend.

There is indeed a feature in the trend at Oct 13 02:51 UTC, but it is uncorrelated in time with the two changes mentioned above. Indeed, the longer trend shows that the OFS has been glitching semi-regularly for at least 30 days. I'll have Detchar investigate whether any of these correspond with heightened period of glitching in DARM, but as of yet, I'm not sure we can say that this glitching in a problem.

 Possibly after some changes made durring maintence, the lockloss tool stopped working. I can use lockloss plot, but not select. 

sheila.dwyer@opsws4:~/Desktop/Locklosses$ lockloss -c channels_to_look_at_TR_CARM.txt select