J. Kissel, K. Venkateswara, M. Ross, J. Driggers

We've built the control infrastructure for the newly installed Compact BRS. This stuff now lives in the h1ngn (the Newtonian Noise model on the h1oaf computer) front-end model. The control scheme follows the diagram as described in T1600325. Screen shots of the various models attached.

Also, because the DAC_0 card on the OAF machine is shared with the (we think the H1 Only) AUDIO infrastructure in the h1oaf model, we've also modified that model aesthetically to indicate that this DAC card is shared.

The models have been successfully compiled and committed to the userapps svn repo here,
/opt/rtcds/userapps/release/isc/h1/models/
h1ngn.mdl
h1oaf.mdl

Measured 167.3W at the output of the high power oscillator.  162.5W at the input to the pre-modecleaner
with the ISS off.

    The diffracted power versus offset slider position was measured.  Combined with the power out of the
laser, this gave the percentage diffracted power.  The free-running peak-to-peak power fluctuations
measured by the ISS photodiodes as reported by a trend of the PDB EPICS was 0.2Vpp with a mean value of
8.3V.  So the 0.1Vp fluctuations represent ~1.2%.

    Allowing for some margin, we wish to diffract 2%.  2% of 162.5W is 3.25W.  With the digital support
loop on, this corresponds to an offset slider of ~2.5.

    The polynomial fit calculating the percentage diffraction was: 220.159x**2 - 97.169x + 11.293.
This was changed to match the measurements done earlier to day to: 97.6751x**2 - 63.548x + 11.458.  The
MEDM screen now correctly reports the amount of light diffracted by the ISS AOM.



Jason/Peter

Bubba, Chandra, Gerardo, Kyle

HAM 6 took one hour to vent to atmosphere, The north & south doors were removed before lunch. GV 5 & 7 were soft closed prior to vent. Attached is vent pressure plot from today and also from April, for comparison.

NOTE: in addition to powering off all HV in HAM 6, we also powered down the ITM HV.

Y2-8 ion pump not operational 

[Betsy, Koji] @Bonding lab

The OMC is sit in the bonding lab for curing of the epoxy. Otherwise, it is ready to be moved to the chamber side.

- 3rd OMC optics cleaning

Attachment 1:
We applied FirstContact cleaning of the optical surfaces. The optical side of the breadboard was wiped with IPA-soaked cloth (without touchting the optics).
The FCs will be left until the OMC is brought to the chamber side.

- PD replacement

Attachment 2:
The original OMC DCPDs were replaced with the new high QE DCPDs. The PDs at the BS transmission and reflection sides are from the PD cage A slot 3 (A3) and A4, respectively. They correspodns to the PD serials B1-01 and B1-16. The final testing at Caltech showed the QEs of 0.980 and 0.981 respectively.

The FirstContact seals are attached on the PD apertures to prevent particulates come into the PD surfaces.

- Mounting blacket bonding reinforcement

Attachment 3:
We added a glass prism to reinforce the bonding of one of the mounting blackets on the top (suspension) side of the OMC breadboard. A small amount of glue residue form the existing bond was removed by a razor blade to clean the place for the new prism. As small amount of glue as possible was applied to have round glue foot print, particularly on the glass-glass joint. The glue on the Invar-glass joint looks round. The glue on the glass-glass joint looks square inspite of our effort (We really don't think it is an issue). A steel block was added to hold the prism until the epoxy is cured.

I was bit again by buzilla bug 1013. The changes I made yesterday (alog28775 =) did not take effect since the change was in common code and I forgot to restart the nodes. I ended up restarting all of the SEI configuration nodes, but really only had to do all of the BSCs. No harm, everything came back nicely.

Illuminators for ETMx and ETMy have been turned off for PCal camera work.

so as to monitor the bouyancy lift of the vent.  Plus, it will likely trip anyway once aggresive activities start.  If the operator and well anybody that notices, keep the ISI OVERVIEW border green by reseting the watchdog whenever the border is not green.  Thanks!

This is in reponse to LLO alog 27053  : " .....  Would be helpful if DetChar can tell us if the OL lasers have been glitchy in the last several months.  ...."

Summary:

I dont think the ITMX laser is mode hopping.  I did not notice any step like changes in the SUM signal, though it is hard to tell due to the periodic pulses.  

The latter can be fixed by tweaking the PID setttings of temperature controller and its set point, I think.

Both ITM oplevs have large resonances at ~60 and ~90 Hz. These are much attenuated in ETMs.  The mounting of ITM oplevs could perhaps be examined to see if there is something out of place.   

QPD Sum calibration:

  At the laser wavelength 632 nm, Si QPD efficiency is ~0.35 A/W; Transimpedance=10kOhm according to D1100290 ; Differential Ouput gives x2 ; 16bit-ADC gives (2^16)/20 counts/V;  

  Using these factors : 1mW of incident light on the QPD would give us ~23k counts.  Since ETMX, ITMX and ITMY oplevs  have 18dB, 21 dB and 15 dB whitening gain,

the incident power on these QPDs is

And 1/4 of that per quadrant !!   

As Hugh noted in his July 19th alog (https://alog.ligo-wa.caltech.edu/aLOG/index.php?callRep=28525) when we reprogrammed the site-wide timing systems on 19th May 2015 and 19th July 2016 the HEPI pump controller units saw a bogus drop in hydraulic fluid pressure. On 19th July of this year the drop at EY was sufficient for the PID controller to attempt to correct, resulting in an excess of presssure which caused problems.

At these times we also saw a bogus increase in cold cathode gauge readings from the vacuum controls system (Kyle put in an alog). Initially I thought more systems were being affected, but today I did some more in depth investigation and the problem appears to be limited to hepi pressure and vacuum cold cathode signals.

At EY I trended all the raw ADC channels in the Beckhoff Vacuum system (terminals M12-16 chans 1-4). The only channels which saw an increase were M11-chan2, M12-chan1 and M12-chan3. These are the input signals for the three cold cathode gauges. When we trend these same signals from May 2015 (back when the computer was the orignal VME system) these same signals show bogus deviations. I looked at the slow-controls Beckhoff system and the weather station, but could not see the problem there.

There are some exceptions to the rule (for example in 2015 hepi-EX did not see a change) but generally when we reprogrammed the timing system the Cold Cathode and Pump Controllers saw a change of input voltage. The question is why only timing reprogramming causes the problem and not the many reboots we have done over the years. I suspect the powering of the 12V units (fanout, comparator, RF Amp, IRIG-b) which we rarely do as opposed to the more frequent powering of the 24V IO Chassis may be a clue.

Tomorrow, under WP 6035, we will go to EY and repeat the power cycling sequence we followed on 19th July. We will repeat everything except for the actual reprogramming. We will be closely monitoring the ADC inputs for these signals. At the end of the excercise Ansel will upgrade the FPGA on the EY fanout using Daniel's latest code.

The alignment into the reference cavity was tweaked.  Mostly a vertical adjustment followed by a
minor adjustment to the yaw.  The transmission as reported on the MEDM screen went from ~2.6V to
~4.6V.

    Measured the power before the lens located in front of the ALS fibre to be 33.4 mW.  At this
time MEDM reported 4.62V.

    With a DMM, the DC output of the locking photodiode was measured.
 - locked: 0.124 - 0.134 V
 - unlocked: 0.772 - 0.777 V
So the reference cavity visibility is 83.3%.  The gain of the filter yielding the DC output of the
locking photodiode was changed from -0.050 to +0.500 as this agreed better with the value measured
with the DMM.  Not sure why the big change other than I had noticed that since the CDS reboot of a
couple of weeks ago, the reflected DC was different.  Perhaps this gain setting wasn't saved?

    For the transmission photodiode, when the FSS was unlocked the DMM measured -1.8mV.  MEDM
reported ~0.121V at the same time.  When the FSS was locked and MEDM reported ~4.6V in transmission
the DMM measured -2.766V to -2.777V.



Jason/Peter

Kiwamu, Nutsinee

A code is scheduled to run at 9 pm tonight. The code will power up CO2 to 1.3W and power it back down to 0W after 6 hours. Please do not touch ITM optics.

I started to look into a faster ASC UIM to TOP stage offloading.

The DC gain ratio of the DRIVEALIGN filter outputs is about PUM:TOP = 23:20000 (pitch) and 30:20000 (yaw). There is a slight mismatch between the optics, but that seems to be taken care of with the CAL filter (FM1 in M0_LOCK).

With that gain ratio, and with FM1, FM4 and FM5 on in the MO_LOCK banks, the current x-over between TOP and PUM is about 0.002Hz (pitch) and 0.0029Hz (yaw).

This is very low. I verified that with 10x the gain in all 4 soft loops (gain=0.45 instead of 0.045) and 10x the offloading gain to top, the soop[s still seem stable. I believe the reason we are not running with that during the angaging these loops tax the SRC loops.

I added 0Hz:0.1Hz AC couplers into the L2 DRIVEALIGN P2P and Y2Y banks, as well as 0.002Hz:0.1Hz lead filters into Mo DRIVEALIGN P2P  banks ( 0.0029Hz:0.1Hz lead filters for Y2Y). These filters were successfully engaged in full lock. Somewhere however the guardian turns up the offloading gain by 10dB, making these filters unstable... So for now they are not in guardian.

Unfortunately, the pwer-up is still failing randomly. Not sure whether that's the 40mph wind, the numerous locked-down hepi's or the increased noise on RF DARM.