The h1nds0 computer died with a kernel panic, fatal exception to interrupt. Rebooted.

J. Warner, K. Venkateswara

This morning we tried X and Z sensor to HEPI. The results on Z are very positive. The first plot of the first pdf shows the ground Z motion / Stage 1 T240Z motion without and with Z sensor correction. It shows an improvement of ~10 at the microseism, with a factor ~2 reinjection between 20-50 mHz. The next plot of the first pdf shows the Pitch motion without and with Z sensor correction, which again shows an improvement of ~10 at the microseism.

With X, things are a bit different. The first plot of the second pdf shows the ground X motion / Stage 1 T240X motion without and with X sensor correction. It shows an improvement of ~2-5 between  a large range 20 mHz to 2 Hz, with maybe a factor ~2 reinjection at 10 mHz. This was similar to the increase in performance when we tried sensor correction to Stage 1. The next plot of the second pdf shows the Pitch and Yaw motion without and with X sensor correction, which looks the same above 50 mhz, but shows a factor ~5 increase below that frequency. We saw a similar increase when doing the sensor correction to X as described in 14570. Jim and I suspect that the tilt and yaw decoupling from X at Stage 1 (or HEPI) might not be good enough so we will repeat that measurement later.

Bottomline: Z sensor correction to HEPI works great. It works better than Z sensor correction to Stage 1. X sensor correction to HEPI/Stage 1 produces similar results - It improves performance at Stage 1 X but increases Pitch and Yaw motion at low frequencies, probably due to tilt and yaw coupling with X drive/sensing. Better tilt decoupling may help.

Edit: I had a calibration error in the plots, which has now been corrected.

LVEA: Laser Hazard
Observation Bit: Commissioning

08:46 Betsy – Quad work in LVEA West Bay 
11:46 Rick & Joe – End-Y PCal transmitter installation
11:53 Betsy – Out of LVEA
12:50 Jonathan – Restart of Mobil Authentication System
12:56 Krishna – Going to End-X to work on BRS
13:57 Betsy & Travis – Quad work in LVEA West Bay
14:06 Filiberto – End-Y install PCal power supplies in rack
15:41 Betsy & Travis out of LVEA

Hugo & Hugh

With new ISI TFs from Sept 16 when the ISI was Under Vacuum with the HEPI Position Loops closed, I made new Level 3 control scripts for HAM2.  I took the ISI down with Guardian pausing the manager and putting the ISI in READY.

In this state, the local 2 cartesian (& back) matrices were corrected--the X Y RX & RY signs were incorrect-- using the Populate_Matrices_HAM_ISI.m function.  As expected, the cartesian sign of these dofs switched and the Target Position was correspondingly changed (by hand.)  I then loaded the new filter file.  Everything as expected so far.  When the ISI Guardian was set back to High Isolate, it performed as expected until it was changing the horizontal dof gains from 0.01 to 1.0.  At this point it trips in a fraction of a second on the GS13.  In subsequent attempts it almost always repeats this behaviour although sometimes the trip was the actuator rather than the GS13, see the attached for example and zoom in.

OK so I screwed up the controllers.  We tried level 2 controllers. Wait Guardian isn't set up to do level 2 so I try the old ISI Command scripts: yes it works on level 2 & level 1...

So Okay, I must have screwed up the controllers.  I reverted back to the achive file that was made Oct2 10:16: still Guardian trips the level3 attempt at the same spot... revert back to Oct2 10:13 (what's up with that?.)  Same result.

We try some manual turn on, that is 1 dof at a time, hey we can isolated this way.  Then we take it down again and try with Guardian, no, it still turns on the Vertical Dofs fine but trips when switching the Horizontal dofs from0.01 to 1.0 gain.

Then! Then we try level 3 with the old ISI command scripts--it works!  We turn Guardian back on, take the ISI down to ready and then attempt to get back to Isolation, nope, sorry, still trips.  Back up to level 3 Isolation with the old ISI command scripts.  This is where it sits...Strange.

Strange in that the ISI command script turns RX & RY dofs on first while Guardian does Z RX & RY first.  Then when the command scripts have to do Z X Y & RZ, Guardian only has to do X Y & RZ.  Plus, guardian does everything sequentially as in it waits for boosts to be on before he next step whereas the old command scripts are often doing more things at once such as engaging the boost while starting the Alignment bias servoing.

So we have to conclude that something must be up with Guardian although it seems unlikely.  I restarted all Guardians 16 October and all went back to high isolate with no problem.

We have a before these changes performance plot.  We'll take another look after things settle down and compare.

Summary

Matrices and Controllers reverted but ISI will not Isolate with Guardian.  It does Isolate using the old ISI Command Scripts.

Looked at EY seismometer yesterday morning and found unit disconnected from power supply. Re-terminated cable ends with appropriate banana connectors. Robert S. reports spectrum for unit looks good.

model restarts logged for Wed 22/Oct/2014
2014_10_22 08:29 h1fw1
2014_10_22 09:25 h1fw1
2014_10_22 19:28 h1fw1

all restarts unexpected

Rana, Evan, Kiwamu, Alexa

Tonight we worked on the ASC WFS again. We noticed that the P,Y had different integrators loaded even though they were named the same thing. There was also a high frequency gain of -30dB in the integretor. We have adjusted this filter (see attached photo of the new filter FM1, and second image with FM1 and FM2 on). We also aborbed some of the overall filter gain in FM1, so that the gains are not as small as before. We can now close the loops for PRMI, and they are stable. The configuration is as follows:

We noticed that there is a bit of coupling between the REFL_A_RF9_I pitch and yaw signal; however if the DC alignment is suffeciently good the loop is still stable. The ASC WFS then bring POPAIR_B_RF18_I_MON to ~170cts. These changes are reflected in the guardian. (The old gains are commented out, and the old FM1 filters remain in the SRCL loop in case we need to revert anything).

We continued on to DRMI. The PRCL loop worked fine. However, the above configurations for MICH failed. The loops would drive the BS cntrl too far off too quickly, and we would lose lock. Unfortunately, the DRMI lock acquisition time is extremely long, and trying to adjust this loop was difficult. We got tired....

Rana, Kiwamu

In order to study why the DRMI seems to lock faster at 1 Watt (see alog 14508), we checked the RF level of REFLAIR_A which is the one we use for acquiring lock of the DRMI.

The RF level at the output of the PD can be as high as -5 dBm and 3 dBm at maximum for 9 and 45 MHz respectively. This may be a bit too high, but certainly not outrageously too high.

(some details)

We hooked up a 300 MHz oscilloscope to the RF mon of the demod boards and checked the RMS value of the RF signals when the DRMI was flashing. Using the trigger on the scope, we captured two incidents where the RF level was high as follows:

• case 1 (triggered by the 45 MHz signal):
  • 9.29 mV rms or -27.6 dBm at 9 MHz
  • 21.8 mV rms or -20.2 dBm at 45 MHz
• case 2 (triggered by the 9 MHz signal):
  • 9.32 mV rms or -27.6 dBm at 9 MHz
  • 8.78 mV rms or -28.1 dBm at 45 MHz

Since the attenuation from the RF input to the RF mon on the demod board is 23 dBm, the real input signals must have been bigger by 23 dB than what we observed on the scope. Therefore the highest signals we expect at the output of the RFPD are -5 dBm and 3 dBm at 9 and 45 MHz respectively.

Note that when the DRMI was locked, there was almost no RF signals. We occasionally saw small signal of about -40 dBm at 45 MHz which we think was some kind of seismic excitation.

Jeff, Rana, Alexa, Kiwamu, Evan

Rana noticed that the BS oplev spectra (pitch and yaw) were suspiciously flat, perhaps indicating that they were dominated by ADC noise.

To fix this, Rana and I attached a DIP-switch jumper board (D1001631v2) to the 37-pin dsub on the BS oplev whitening board. This allows us to set bits that control the gain and whitening.

For each of the four segments, we flipped bits 2 and 4 (which increases the gain) and bit 5 (which engages a single whitening stage) to high; all others are low. Then we engaged the antiwhitening filters for each segment.

The first attachment shows the BS oplev spectra before (green, brown) and after (cyan, magenta) the gain+whitening+antiwhitening, with the loop off. We now appear to be resolving more features in the spectra.

The second attachment shows the BS oplev spectra after gain+whitening+antiwhitening, with the loop off (cyan, magenta) and on (red, blue).

J. Kissel

I've installed the refined alignment slider gains from 14405, and subsequently measured the optical lever calibration gain refinement for H1SUSETMX and H1SUSETMY using the method described in LHO aLOGs 14387 and 14312. I attach fits to the data points. The newly refined oplev calibration gains are 
EX P = 81.2  [urad/ct]
   Y = 115.2 [urad/ct]
EY P = 77.94 [urad/ct]
   Y = 53.55 [urad/ct]
Further, I've installed the already-computed, refined optical lever calibration gains for H1SUSBS from LHO aLOG 14387, compensated for the change in the optical lever damping loops, and confirmed the loop is still functional.

I've captured new safe.snaps for all three suspensions to ensure these values stick.

As such, all core-optic, BSC suspensions have optical lever gains refined precisely to a few hundredths of a percent (i.e. the separation of the baffle diodes, ~30 [cm] over the length of the arms 4 [km].)

Details

The ETMX P fitted correction factor is:
0.8805 ["urad"/urad]
The new ETMX oplev P calibration should be:
71.5 ["urad"/ct] * 1.136 [urad/"urad"] = 81.2 [urad/ct]
The ETMX Y fitted correction factor is:
1.058 ["urad"/urad]
The new ETMX oplev Y calibration should be:
121.8 ["urad"/ct] * 0.9455 [urad/"urad"] = 115.2 [urad/ct]
The ETMY P fitted correction factor is:
1.225 ["urad"/urad]
The new ETMY oplev P calibration should be:
95.5 ["urad"/ct] * 0.8161 [urad/"urad"] = 77.94 [urad/ct]
The ETMY Y fitted correction factor is:
1.295 ["urad"/urad]
The new ETMY oplev Y calibration should be:
69.33 ["urad"/ct] * 0.7724 [urad/"urad"] = 53.55 [urad/ct]

The raw measurement data and script to process it can be found here:

/ligo/home/jeffrey.kissel/2014-10-22/
calibratebsoplev_20141021.m
2014-10-22_H1SUSETMX_OplevCalibration_P_Offsets_10sec_avg.txt
2014-10-22_H1SUSETMX_OplevCalibration_Y_Offsets_10sec_avg.txt
2014-10-22_H1SUSETMY_OplevCalibration_P_Offsets_10sec_avg.txt
2014-10-22_H1SUSETMY_OplevCalibration_Y_Offsets_10sec_avg.txt

9:23 am, Filiberto to X-End station to pick up tools then to head to work at the Y-End station, also fix the seismometer.
9:30 am, Aaron to the X-End station to terminate a cable.
10:17 am, Karen to Y-End and Y-Mid stations, cleaning duties.
11:10 am, Betsy to the CS VEA, look for items by the PSL area.
11:30 am, Betsy exits CS VEA.
11:43 am, Kyle to Y-End station VEA area, working with purge air system.
11:48 am, Karen heading back from Y-Mid station.
12:12 pm, Kyle leaving Y-End station.
1:26 pm, Kyle to Y-End station VEA area, continue with work.
2:25 pm, Kyle leaving Y-End station.
3:35 pm, Kyle heading back to Y-End station, continue with work.
3:54 pm, Doug to the CS VEA, looking a small circuit board.

Following the measurement of the power recycling gain (alog 14532), I made an estimation of round trip loss in the power recycling cavity.

In order to explain the recycling gan of 21 for the 45 MHz sidebands, round trip loss needs to be 2.3%.

The plot shown above is power recycling gain for the 45 MHz sidebands as a function of round trip loss. The blue curve represents the one without losses but with the effect of the Schnupp asymmetry. The green one is that with all the known losses included.

For more details, see the attached python code. Also, the highest gain we can achieve is 42 for the 45 MHz without round trip losses. Note that I assumed both ITMs to have the same curvature and also I have not included the mode matching effect.

• Work permits update.
• Pcal group:to work on both systems the rest of the week, at both end stations, including laser activity.
• OpLev group: setting up assembly area, and assembly of damping components to be installed on piers.  Jeff K. to work on OpLev calibration.
• Report of Y-End station seismometer out, part of the LHO PEM system, Filiberto to look into it.
• SEI group: commissioning of sei-systems.

I restarted the DAQ at 10:40PDT Tuesday morning to connect the EDCU to the new Beckhoff channels (PCAL at EX,EY, OMC renaming at C1). After the restart we noticed that the ALS_COMM guardian was stopped. The log file gives the error "no NDS servers available" at 10:40.

Looking into the code, the DOWN state of ALS_COMM calls the cdsutils.avg for the DAQ channel H1:ALS-C_TRX_A_LF_OUT_DQ to average this channel over 0.1 seconds. This NDS call failed when the DAQ was restarted and ALS_COMM remained stopped until a RELOAD was performed at a later time.

Looking at the guardian logs, two other systems have shown "no NDS servers available" errors: ISC_DOF and LSC_CONFIGS. In these cases they were not associated with an NDS restart, and were immediately followed by a guardian RELOAD (within a minute).

J. Warner, K. Venkateswara

We tried sensor correction in Z direction on HEPI using the GND_STS, while keeping the X direction sensor correction on Stage 1 using the ground super-sensor. The two attached pdfs show the result before and after. The result is almost the same level of performance in both X and Z with some improvement in Oplev YAW motion at ~0.15 Hz with HEPI sensor correction. This probably reduces the Stage 1 Z actuation, hence reducing the Z to RZ coupling.

We will try the X sensor correction to HEPI in the afternoon, after install activity at EX is completed.

model restarts logged for Tue 21/Oct/2014
2014_10_21 09:42 h1isietmx
2014_10_21 09:44 h1hpietmx
2014_10_21 10:36 h1dc0
2014_10_21 10:41 h1dc0
2014_10_21 10:41 h1nds0
2014_10_21 10:43 h1fw0
2014_10_21 10:43 h1fw1
2014_10_21 10:43 h1nds1
2014_10_21 10:54 h1broadcast0
2014_10_21 15:43 h1fw0

one unexpected restart of h1fw0. Maintenance day modification of SEI ETMX and associated DAQ restart. Beckhoff duplicate channels resulted in two dc0 restarts.

Took the ITMX ISI down to load proper filters for the ISI-HEPI L4Cs.  Corrected the L4CtoCartesian matrix and made a new safe.snap.  Back and running under Guardian.  Safe.snap committed to svn.

Alexa, Kiwamu

We did three items tonight:

1. We tried the good IM4 YAW bias that Keita found out today (see alog 14567) by steering PR3/PR2 and IM4.
   • => failed and got confused. We set these biases back to the usual values.
2. We made a comparison of the DRMI spectra with and without the BS yaw oplev damping loop
   • => found that the BS yaw oplev loop was contaminating the length signals and also increasing the chance of the SRC hopping.
3. We checked tolerance in the angle of the SRC-related optics by intentionally introducing offset.
   • => BS was the most sensitive optic which let the DRMI enter the 01 mode instability with misalignment of about 0.2 urad.

(IM4 angle)

We aimed for -8000 counts in IM4 yaw bias which is the value that Keita found out to be good from the point of view of cavity loss. We did this by steering PR3 while keep closing the IM4+PR2 ASC loops for the input pointing with respect to the arm cavity. This resulted in yaw biases of -162.70 and 762.99 urad for PR3 and PR2 respectively. The original biases were -177.30 and 629.26 urad respectively. Since this resulted in misalignment in the POP beam, we had to steer some optics on ISCT1 to recover the light on the POP diodes.

However this resulted in a weaker light at the POP path, due to a clipping somewhere in chambers. The POP beam did not like a Gaussian beam any more and looked enlongated vertically. See the attached movie for getting idea of how it looked like. The movie shows the POP beam in front of the top periscope mirror on ISCT1. The power build-up in POPAIR_RF18 was smaller by more than a factor of 5. I think this is a clipping in somewhere in the POP path at the outside of the PR cavity because we could lock the DRMI without changing the LSC gains -- the optical gains stayed almost the same.

We decided to go back to the nominal angles and set PR2 and PR3 back to the usual values. We realigned the optics on ISCT1 again. 

One thing we got confused is that, after restoring PR2 and PR3 back to the usual values, the IM4 YAW bias did not have to move at all in order to get a good pointing toward the X arm. Maybe we simply do not understand what we are doing.

(DRMI length signals are contaminated by BS YAW oplev damping)

During the IM4 anlge study, we came up with a hypothesis that somehow the BS oplev damping loops were kicking the BS and let the SRC hop to some other modes. So we made a comparison with and without the oplev loops running. We found the following two facts:

1. BS YAW oplev damping loop was contaminatong the length signals at around 10 Hz
2. Engaging the yaw damping loop seemed to increase the number of hopping.

The plot below is the DRMI spectra with and without the YAW oplev damping loop. Note that the PIT loop was untouched and left on all the time during this measurement:

The ones in vivid colors (red, blue and green) are the spectra with the oplev loop running. The other curves are the ones without the oplev loop running. It is obvious that the noise between 4 and 20 Hz increased by some amount. In particular, the noise level in SRCL increased by roughly an order of magnitude. This contaminatin was repeatable.

(Tolerance in optics' angle)

We introduced intentional misalignment in the SRC optics in order to see how big misalignment they can tolerate. The below are the measured tolerance that gave us the 01-mode instability:

• BS = 0.2 urad
• ITMX = 0.5 urad
• SR3 = 0.5 urad
• SR2 = 4 urad
• SRM = 16 urad

All the numbers shown here is for the yaw direction. We did not measure it in pitch.

I found that the HAM2 ISI had been tripped at around 22:00 PDT probably because of me leaning against the HAM2 HEPI peer on the east side.

After I untripped the watchdog, the ISI had a difficulty coming back on its own under the control of the guardian. One time it failed during the X/Y/RZ gain ramping for some reason. I did not look into the detail. Also, in another time, it failed because GS13s saturated during the engagement of Z/RX/RY. Again I did not look into the details and don't know what specific state it was at when failing. Eventually, I decided to go through the process step by step by pausing the guardian at each step. However at this point, it smoothly went and it did not fail. Anyway it is back and running fine now.