Richard, Jim, Dave:

We programmed all the remaining IO Chassis timing slave FPGA's today. In the morning we did MY and EY. This afternoon Jim did all the corner station chassis (SUS, SUSAUX, SEI, PSL, ISC)

We replaced all18bit DAC cards with new firmware versions in: h1susey, h1susb123, h1sush2a, h1sush34. Remaining SUS to do, h1sush56, h1sush2b. We have enough modified cards to do h1sush56 tomorrow, using the one card which fails on autocal* for the OMC DAC.

We had to shuffle some DAC cards around to make space for the new DC power supply. Details will be posted tomorrow.

We powered up all frontends. There is a problem with h1seib3, looks like the 16chan Contec BIO card is not being seen by the front end (it was in the slot we needed to use for the DC power supply). Will fix this tomorrow.

Some FECs have large positive IRIG-B values which will eventually come back down.

* 18-bit DAC card S/N 101208-05 fails its autocal. I replaced its firmware chipset and re-tested on DTS, it still fails. Jeff and Dan H suggest for now we install on h1sush56 for the OMC drive.

Dan, Greg, Jim, Dave:

Dan found that one of the LDAS Q-Logic fiber channel switches is reporting receive errors. These errors correlate to the SATABOY RAID controller reported errors, and in turn to the fw0 restarts.

We first changed which the long-haul single mode fiber optics pair which is used between buildings. Instead of using the first pair of the A-Block, we moved to the first pair of the B-Block. The change was done at 15:00 PDT this afternoon. This did not fix the problem, h1fw0 restarted 50 minutes later and Dan saw errors on the Q-Logic switch.

Following the philosophy of "one change at a time", we are swapping out the single mode fiber optics cable in the LDAS server room which connects to the Q-Logic switch to the LDAS patch panel. It that does not improve the situation we will do the same in the MSR.

Sudarshan, Dave:

After the PSL front end restart following the DC power and FPGA reprogramming, we manually burt restored all four models to 13:10 PDT. The safe.snap files for the PSL most probably should be updated.

Summary:

Now the ISS second loop  RPN signals  ( H1:PSL-ISS_SECONDLOOP_SUM14_REL_OUT_DQ and   H1:PSL-ISS_SECONDLOOP_SUM58_REL_OUT_DQ) are normalized using the DC signals from the photodiodes.

Before:

The original electronics on the photodiode readout for ISS second loop had a whitening so we were not able to get the DC signals.    Temporary arrangments were made to monitor these DC signals by using testpoints but they were not included in the front end model.  To calibrate the output signals we were using  a  constant number (12 V in our case) which was obtained by taking the DC signals from the test point when the ISS was operating at its nominal configuration at about 2.8 W.  However, this calibration factor changes with the change in laser power.

After:

On our last  ISS second loop model update (see alog18381)  we included these DC channels into the front end model so we can acquire the DC signals from the photodiodes.  Now the ISS output signals are calibrated (normalized) using these newly acquired DC signals.  See attached filter module to see the changes that have been implemented.

LVEA: Laser Safe
Observation Bit: Commissioning 
  
07:00 Karen & Cris – Cleaning in the LVEA
08:17 Hugh – Going into the LVEA
08:28 Party Rentals on site to setup
08:30 Jodi & Bubba – 3IFO work in LVEA
08:30 S & K Electronics – Electrical work at End-Y and End-X
08:33 Cris – Going to End-X and Mid-X
09:00 Richard – Going to End-Y
09:05 Audio/Visual person on site to setup
09:10 IO Power Supplies & 18-bit DACs (Richard)
09:15 Reprogramming of IO Chassis Timing at EY (Dave & Jim)
09:20 Beckhoff Code Change (Patrick)
09:28 Praxair on site for Nitrogen delivery
09:52 Jim & Dave – At Mid-Y for PEM chassis swap
10:15 Jim – Shutting down Seismic computers for Work Permits 5207, 5205, 5204
12:10 Jim & Dave – Going to End-Y
12:30 Jim & Dave – Back from End-Y
12:56 Jim & Filiberto – Shutting down SUS computers for Work Permits 5207, 5205, 5204 
13:49 Jeff K – End-X doing SUS measurements
14:00 – 15:30 – Tours in LVEA and Control Room
15:02 Jim & Dace – Shut down PSL & ISC frontends for Work Permits 5207, 5205, 5204
15:03 Catering group on site to clean up after lunch

Burtrestored to 7:10 this morning.

Daniel, Dave, Patrick

Daniel added 100 to the list of acceptable Duotone firmware code revision numbers. I added 133 to the list of acceptable IrigB firmware code revision numbers.

Restarted PLC1 on h1ecatc1, h1ecatx1 and h1ecaty1. Burtrestored each to 07:10 this morning.

WP 5216

WP 5202

Updated nds2-client software to nds2-client-0.11.6 for Ubuntu 12, Ubuntu 14, and Scientific Linux 6 computers.

J. Kissel

I'm heading down to the X end to begin measurements of the QUAD's AI and Coil Driver Chassis. I've brought the QUAD to SAFE in prep. 

At some stage last night, or this morning the laser tripped.  Since the laser is not needed
right now, I have not reset the laser as we're trying to debug why it is the laser is
tripping in the first place.

  PLEASE DO NOT RESET THE LASER.

Summary: Coupling of ambient sound is predicted to approach the DARM noise floor below 100 Hz and in the ISI-transmission bands of 350-550 and 850-1000 Hz. Twice the ambient vibration level causes a peak to appear in DARM in the 850-1000 Hz band. At several times background, injections produce nonlinear intermodulation effects, possibly with the OMC length dither, causing DARM peaks in the 100-200 Hz region and at much higher frequencies. The coupling in the 850-1000 Hz band depends on table motion, not vacuum enclosure motion.

I began studying acoustic coupling in the LVEA using the standard iLIGO LVEA injection (speaker in the X-arm of the LVEA, far from interferometer parts except the ITMX optical lever) and immediately noticed strong features in the 850-1000 Hz ISI-resonance band that suggested up-conversion. I then began injecting in narrow bands to study coupling; Figure 1 shows the up and down conversion produced by injections in the 850-1000 Hz band. The 500-700 Hz injection in blue produced only features in that band of DARM. But the red injection, 850-1000 Hz produced features in DARM near 100 Hz and in the region of the first harmonic around 1800, in the region around 2400 Hz, and near 4200 Hz.

Predicted noise from acoustic background

Figure 2 shows the estimated noise floor for ambient acoustic levels. It relies on the assumption of linearity, that is, that 10x the ambient sound will produce 10x the effect in DARM. Linearity is clearly not met in the 850-1000 Hz band. However, Figure 2 is made from 6 narrow injection bands (such as in Figure 1), at 10 to 100 times background sound pressure levels, and, except for the 850-1000 Hz band, none of the other bands showed evidence of non-linear coupling. The predicted ambient noise level for the 850-1000 Hz band is better estimated for the shaker injections below. The predicted ambient points have a wide spread mainly because the microphone is not exactly at the coupling site and, for example, at certain frequencies, the microphone may be at a node or antinode while the coupling site is not. More focused coupling measurements can be more precise. All LVEA beam diverters were closed for acoustic injections except the REFL port.

Figure 2 shows three bands where the predicted ambient noise approaches the noise floor: below 100 Hz, in the 350-550 Hz band, and the 800-1000 Hz band. The later two are familiar ISI transmission bands, which suggest that the coupling is at HAMs. I have not yet measured acoustic coupling at higher frequencies than 1100 Hz because I was not able to make the sound loud enough over a wide band (generally the coupling is low), but it is likely that there is significant coupling at specific higher frequencies because it was observed in shaker injections at HAM6.

Shaking at HAM6 (which excites only locally in contrast with the previous acoustic injections) confirmed that coupling at HAM6 could account for the acoustic coupling in the 850-1000 Hz band, though it doesn’t eliminate the possibility that there is comparable coupling at other sites. To make these HAM6 measurements I mounted a shaker on a blanked off door port and another on a blue cross beam.

DARM amplitude depends on table motion not vacuum enclosure motion

I compared the response of DARM for shaking of the vacuum enclosure (which is a candidate reflector of scattered light), and for shaking of the blue cross beam, which doesn’t shake the vacuum enclosure much but does couple well to table vibrations. Figure 3 shows that, in order to produce a peak in DARM as large as the one I produced by shaking the blue cross beam, I had to shake the vacuum enclosure so that it moved ten times as much as it moved during the cross beam injection. While the enclosure motion varied by 10, the table motion indicated by the GS13 signal was about the same for both injections. This suggests that , in the 850-1000 Hz band, the important motion is the table motion not the vacuum enclosure motion.

Increasing HAM6 table motion to twice ambient produces features in DARM

Figure 4 shows that increases in table motion of two times ambient background (black = ambient), in the 700-900 Hz band, produce features visible in DARM, and non-linear effects become obvious at 5-10 times ambient.

Non linear effects in DARM at higher frequencies and the OMC length dither

Shaker injections at higher frequencies also make peaks, e.g. a 2875 injection produces a peak in DARM at that frequency and another peak at 1220. To demonstrate the nonlinear effects, I injected a slowly swept sine with a shaker on a blue cross beam, and made a video of the DARM spectrum:  http://youtu.be/t6zlUlckuEI  I apologize for shooting video of the control room screen; we don’t yet have software that makes a movie from sequential screen shots, though it is available and might be useful for operator training videos as well as projects like this. 

It is hard to imagine mechanical nonlinearities that could account for these observations, but if the excited motion modulated the beam, I could imagine intermodulations. One possibility, based on the video, is that mechanical oscillations that modulate the beam could be intermodulating with the OMC length dither. Notice in the video that upward and downward travelling peaks are centered on the peak at 4100 Hz (or its sub-harmonic at 2050). The 4100 Hz peak is from the OMC length dither.

Robert

Jeff, Richard, Jim, Dave

WP 5205,5207

Today we performed the following upgrades at EX:

• Install the 18bit DAC cards with the upgraded firmware into h1susex
• Install the new DC power supplies into the IO Chassis for h1susex, h1seiex, h1iscex and h1susauxex
• Program the IO Chassis timing slaves with firmware version 100 for all four chassis

One of the new 18bit DACs caused problems when starting h1susex. At the point where the autocal should have completed, the front end computer froze up. We identifified the bad unit and replaced it with another new card which resolved the problem. The potentially bad card has S/N 101208-59 and was returned to the corner station for DTS testing.

The interface board on h1seiex had a connector issue when the old DC power supply was disconnected. We exchanged it with the I/F board from the DTS x1sush34 unit (a tried and tested board).

The DAC card layout in h1susex did not provide enough room for the new DC power supply. We shifted the DAC cards to the left (as seen from front of unit), and while diagnosing other issues moved all DACs to higher slot numbers than the one ADC card. We may undo this and keep the DACs in a block of five.

here is the current card layout for h1susex:

Where: U=unused, nu=not used, BIO=64,64 Binary IO, E=Empty, bio=16,16 Binary IO, PWR=new DC power supply

We also experienced startup issues with the Dolphin network. We tried power cycling the switch, but restarting the Dolphin manager and then restarting the front ends resolved the issue.

We had to start_streamers on the Dolphin machines as well to sync up the DAQ.

At this point in time all is running at EX, the only problem is h1seiex has a run away IRIG-B which may take several hours to come back down.

Jeff activated the HEPI, ISI and SUS systems at EX, all is operational.

AA AI chassis swap will continue tomorrow morning. We are currently working on PSL, so not all chassis are connected or powered on.

Today started off with VEAs being transitioned to Laser Safe and many activities beginning with the AA/AI Chassis swap being the prime activity.

• 7:00 Cris/Karen cleaning
• 7:55 Turning off ALS lasers (Richard/Peter)
• 8:45amPowered off TCS CO2 Lasers via medm (Peter turned key on power supply)
• 10am:  ISCT EX Access System Sensors (Ken)
• 10:20:  EX HEPI Pump station started alarming.  Looks like it's noise from a poorly grounded Sensor (noted by Hugh).
• 10:30 A Bing Car (with camera on roof) zipped around the LSB/Front Gate (attached)
• 10:33-11:01 Jodi sealing up 3IFO containers.
• 11:17 Travis running hardware to AA/AI crew at end stations
• 11:25 Tomorrow tour prep in LVEA (Hugh)
• ISS instable, RefSignal moved from -1.95 to -1.93.
• Jim/Richard - shutting down EX, so offline - went offline before we could complete the change to SAFE/OFFLINE.  Cheryl set Guardian to request SAFE/OFFLINE for SUS and SEI.
• Filiberto called - we changed all corner station and EY SUS and SEI to SAFE/OFFLINE, EY may not have been necessary for today, but with everything else down, it made sense to do EY also.
• 1:30-3:30 Jeff checking garb at all VEAs
• 3pm Mid-stations were getting warm (received FMCS alarms), so Bubba turned on the Air Handlers.
• 3:05:  Bubba off to EX Lab room to check on HVAC unit
• 3:11-3:30 Jodi in LVEA for 3IFO again
• 3:30 CDS crew came to take a break from EX work, but will be heading back out to continue working on power supply stuff.
• 3:20 AA/AI crew continue work in H1 Elec Room & are now working on PSL (Filiberto, Richard, et. al)
•  

Peter F, Kiwamu,

We looked into the DARM cavity pole tracker signals from the 13 hrs lock stretch from this weekend (alog 18489). Here are summary points:

• The DARM cavity pole showed a long-term drift (on a time scale of 13 hours). The frequency degraded from 350-ish Hz to 328-ish Hz.
• We did not find a high coherence between the cavity pole tracker signals and the following channels:
  • SUS_SRM_M1_LOCK_P(Y)
  • SUS_SRM_M3_WIT_PIT(YAW)
  • SUS_SR2_M1_LOCK_P(Y)
  • SUS_SR2_M3_WIT_PIT(YAW)
  • SUS_BS_M1_LOCK_P(Y)
  • TCS-ITMX_HWS_PROBE_SPHERICAL_POWER
  • OMCR
  • TRX and TRY
• No idea what caused the change in the DARM cavity pole.

[DARM cavity pole tracker signals]

The plots below are the results from the cavity pole tracker:

In both plots, the long stretch started at t = 9.5 hours or so and died at the very end of the plots. The first plot shows the cavity pole location as a function of the time. In addition to the raw data, I also plot a moving-averaged version of the cavity pole location. The movng average currently avarages with 360 data points or for 6 minutes to smooth them out. The same moving-average was applied to the optical gain as well for visiualization purpose.

As shown in the first plot, the DARM cavity pole tends to start from a frequency as high as 350 Hz at the beginning of every lock stretch and then sink down to about 340 Hz after an hour or so. This probably is thermal transient of ITM substrates on the local beam area. Also there clearly is slow drift in the cavity pole which resulted in a low DARM cavity pole frequency of about 328 Hz at the very end of the long lock stretch. According to Elli, the test masses reach the equilibrium point on a time scael of 6 hours, where the heat absorbed from the laser light equilibrate with the entire thermal bath including the chambers and etc. But, since the cavity pole kept drifting for more than 6 hours, it is not clear if we can conclude that this is the thermal lensing. On the other hand, the DARM optical gain increased in the longest lock stretch on the same time scale as the stretch itself. It increased by 1 or 2 %. Since the arm power also slowly increased by roughly 1 %, this may be just an indication of the change in the arm power (and perhaps also degradation in the signal-recycling gain).

[Searching for coherence]

One test we came up with was to take coherence between the cavity pole tracker signals (LOCKIN_I and LOCKIN_Q output signals) and various channgles in order to identify what channels contributed to the cavity pole frequency most. Since we knew that the alignment of SRC was important (alog 18436), we looked into the ASC feedback signals of SRM, SR2 and BS on their top stages,  witness sensors or oplev of SRM, SR2 and SR3 and OMCR as listed in the very top of this alog entry. In addition, since the ITMX Hardtman wavefront sensor was active during this period, we searched for the coherence with it as well.

However, we did not find a high coherence from any of these channels. We used diaggui and picked a time which was roughly in the middle of the stretch. We did a Fourier analysis down to 1 mHz with a number of average of 20. I attach second trends of some relevant channels. Notably we clearly see slow drift in the ITMX HWS by roughly 6x10^-6 [1/m] (there was a secret calibration fact of 0.00326 [1/m/counts]), but this was not coherent with the tracker signals. We also found a slow drift in OMCR which increased by roughly 2%, but no coherence either.

Josh Smith, TJ Massinger, Andy Lundgren, Laura Nuttall

We've taken a look at the ~8h lock stretch on 15th May where the intent bit was active. We've specifically looked for evidence of DAC (for example 17555) and whistle (17452) glitches which have been present in the past. We find no sign of whistles glitches correlated with IMC-F (could be other sources but we haven't seen any yet) and we also find no evidence of DAC glitches. 

The glitch rate for this lock is some of the best we have seen for aLIGO (at either site). Attached is the glitch rate plot for the 15th, which shows the glitch rate to slowly decrease throughout the lock. We'll continue to investigate this lock.

A snapshot of the IFO alignment, in case it is useful later.

I did some broadband intensity noise injections from about 05:04:00Z to 05:32:00Z, 2015-05-17. I also took another frequency noise coupling TF. Noise projections forthcoming.

I widened the BS violin stopband filter (FM5 in BS M2 LOCK L, 80 dB elliptic). In the course of doing MICH noise injections, I saw a wide response around the beamsplitter violin mode, as was seen at LLO (see Brett's post and the posts linked therein for a discussion). The stopband used to go from 297 Hz to 307 Hz; now it goes from 250 Hz to 350 Hz. These injections seem to indicate that the beamsplitter roll mode is also quite wide, but since this is so close to the UGF of the MICH loop I left the bandstop filter alone.

I took OLTF measurements of PRCL, MICH, and SRCL. PRCL UGF is about 45 Hz and SRCL UGF is about 25 Hz. The MICH UGF was about 12 Hz, with 12 degrees of phase (!). It seems the compensation filter from a few weeks ago is no longer necessary in the full, low-noise 23 W configuration. I'm not sure whether it's necessary at some earlier point in the locking sequence, so I've left it in the guardian for now.

We have seen for a while now that when we transition control of DARM from rf to dc readout, the fluctuations in OMC DC can be as bad as 30% pkpk. We've also seen that the interferometer sometimes loses lock either on the transition step, or on the subsequent step of switching actuators from ETMX to ETMY. For the record, one can do the final DARM stabilization steps (bringing the UGF up to 50 Hz, and engaging the boost) before transitioning to dc readout. This reduces the RIN in OMC DC to less than 10% pkpk. Then, in order to switch actuators, ramp the drive of ETMY ESD on simultaneously while ramping the drive of ETMX ESD down. I used a 30 s ramp, but I suspect we could get away with 10 s or less. I have not put this in the guardian.

I have seen the same 0.4 Hz oscillations in full lock, as Jeff reported earlier. To get around this tonight, I left the ITM oplev damping on. Removing the damping even in full lock leads to instability.

Just posting data that Fabrice had requested for a talk. The setup: I wanted to measure the performance of sensor correction on ETMX. I turned off the feed forward (which I've seen add some noise at .5hz, not much, but I've been meaning to investigate) and got .001 bw measurments with the sensor correction on and off. The ISI was fully isolated, with 45mhz blends in Y and 90mhz blends in X. On the first 3 spectra (X,Y &Z) black (ground),orange(st1 t240's) and red(st2 gs13's) are sensor correction on, brown (ground), blue (st1 t240's) and grey (st2 gs13's) are sensor correction off. In X&Y, we are using Ryan's .5hz notch sensor correction on the ISI and in Z we are using RichM's broadband low frequency sensor correction on hepi (fourth & fifth plots).