The ref cav transmitted light kept decreasing over this weekend. I had to set the threshold further down to 0.3 yesterday while the nominal is 0.9. This needs an investigation at some point.
Sheila, Kiwamu,
Today we realized that the centering on MC3 that we did on friday night resulted in a bad mode cleaner alingment. We used DOF 4 to minimize the angle to length coupling of MC3, but this resulted in operating close to the edge of the osem range. While Kiwamu and I were trying to align IM1+IM2 to get through the faradat this afternoon, the mode cleaner got into a state where MC3 was constantly tripping. We plan to go back to the mode cleaner alignment as of friday afternoon, live with the clipping in the IM1 trans path and move on to aligning the IMs and PRM tomorow.
The good news is: we know how to look through the veiwport and align the beams through the Faraday, and IM1+IM2 give us plenty of actuation range to do this.
Our mistakes were:
The beams on the wall are IM4 trans, not IM2 trans. The rumor I started that they were IM2 trans caused us to think we didn't have enough range on IM1 on friday, which is why we started the centering on MC3 in the first place.
We centered on MC3 by introducing an offset to DOF4, which changes more than just the centering on MC3.
We might want to measure the spot positions on all 3 MC mirrors and compare to Jax's measurement in alog 6676, to see if this makes sense.
Just to note: on saturday Stefan and I realigned the IM1 trans path on IOT2L, when we revert the MC to friday afternoon we will have to realign that. This afternoon I restored the PZT to where it was friday afternoon, and restored MC1 to where it was friday afternoon using the witness sensors. After that we realigned the refl path on IOT2L roughly. The next steps are to restore MC2+3 using the witness sensors, and fine tune the alignment on the refl WFS once the MC is locked.
On Friday:
- Apollo finished staging the cleanrooms/garb/work tables/sticky mats, etc.
- Apollo did thorough cleaning of the cleanrooms/receivings/VEA.
- Travis and I staged the EQ needed to remove the lower structure (Ergo arm/pump/monitor box, scissor lift with 5-axis table, stool, tools, LSAT)
- We transported the new PUM, the new Test Mass, and an empty cake tin to Ex.
- Travis started staging the welding EQ - ran into a snag with missing chiller hose fittings (!)
- I started prepping the lower structure for removal (dropped the x-braces, vib absorbers, wedges, and most of the bolts holding the sleeve up). There was a reason the procedures always called for SUS work to take place prior to TMS install. Removing the LS with the TMS in place is a challenge.
It will take Angus, Travis, me, and Jeff or Andres all of Monday to get to the point where we are swapping in the new optics on Tuesday morning. Slow as she goes.
Sheila, Kiwamu, Stefan, Alexa, Arnaud, keita.
Today we started out by projecting the spot on IM2 trans on the wall, and saw that it was so high that we were unable to steer it to the reference (from Oct 4th 2013) with our range (after the coil driver change). After some investigation, we set things back to what we thik the alignment was in late september, using both HEPI and using the BOSEM readbacks for the suspension alingments. After that we saw that the spot was still too high on the wall.
We then started measuring the beam centering using the A2L coupling of MC3. We used the A2L coupling to adjust the offset in the uncontrolled DOF (DOF4 pitch). We have reduced the coupling by a factor of 10.
As a result of the spot position adjustment on MC3, the IM1 trans light moved by this much:
This is a picture of the IM1 trans -- the camera itself is on IOT2L -- and the red sharpie mark at the center of the monitor was for the spot position recorded in this morning. So the beam spot went upward on the monitor i.e. the beam went down because the camera view is up side down. Interestingly, the beam shape improved and becoming more round-ish, indicating we are getting less clipped. Indeed, H1:IMC-TRANS went up from 800 to approximately 1100. Good.
New safe snapshots have been saved for MC1 MC2 MC3 with updated "correct state" for the lock bank (cf screenshot 2), updated bit masks (Bitmasks 8 and 9 were turned off) (cf screenshot 1), and updated alignment offsets during the lock. The ODC status has now its bit 1 to 7 turning green when necessary.
Bitmasks 8 and 9 were turned off using caput from the command line :
caput H1:SUS-MC3_ODC_CHANNEL_BITMASK 254
For x1work, installed nfs server and exported /usr1 for mounting as /ligo. For x1ws0 (iMac), mounted x1work:/usr1 as /ligo to allow native OS X software to run on workstation.
Jim and Dave. We continued the investigation of the problem of incorrect slow channel data in the DAQ from Front Ends following the upgrade to RCG2.8.
The problem is more widespread that just h1hiitmy. We have also seen it in h1susitmy. It appears that only the non-filter-module floating-point slow channels are affected. The problem is related the channel list defined by the INI file. There is a point in the slow floating-point channel list at which channels above do not have the problem, channels below all have problems. The problem is actually a channel shift. For h1susitmy the channels are shifted by 3, for h1hpiitmy the channels are shifted by 2. The point at which the shift starts varies from model to model. It is after a few hundred floating point channels for h1susitmy, and immediately for h1hpiitmy.
Finding the break point is not trivial. Many of the slow channels are zero, or have rapidly changing signals. We are getting the data from the NDS and comparing it with a direct EPICS channel access read of the data.
We will work on scripts over the weekend to get more data on the problem. Hopefully when Rolf is here next week we can implement a fix. The silver lining is that little data has actually been lost, the data is being acquired by the wrong channel name.
Alexa, Stefan, Sheila and Kiwamu
Yesterday, we set up an optical spectrum analyzer on the PSL table to measure the characteristic of the EOM. The results look good except for the 24 MHz resonance . The resonance for the 24 MHz sideband is apart from the modulation frequency by 250 kHz or so. However the IMC doesn't need a large modulation depth and the IMC locking has been OK, we are good. Also, I took some impedance data and will put those data together into a DCC document for a record purpose.
The plots below are the measured modulation depth when driven hard as a function of the modulation frequencies. The vertical dashed-lines represent our actual modulation frequencies i.e. f1 = 9099471 Hz , f_mc = 24078360 Hz and f5 = 5 x f1.
A document summarizing the measurements and their results is now available in DCC (https://dcc.ligo.org/LIGO-E1300966).
I kept forgetting to report the important information regarding to the modulation depths. Here are the estimated modulation depths:
| Modulation depths [rad] | Peak height measured with OSA | RF power at the input | |
| 9 MHz | 0.1 | 20 mV | 12.3 dBm |
| 24 MHz | less than 0.04 | less than 3 mV | 13.8 dBm |
| 45 MHz | 0.07 | 10 mV | 10.8 dBm |
The peak height of the carrier light was about 7.3 V. I used 2 * sqrt(V_sideband / V_carrier) to derive the modulation depths.
LVEA Laser Hazard 08:28 Justin To End-Y to check on laser setup 08:45 Mark Moving ARGO arm to End-Y 08:45 Thomas Optical lever work at ITM-X 09:00 Sheila Removing viewport cover for IM2 09:15 Mark Craning ITM-Y lower structure over beam tube 09:25 Filiberto Pulling cables by BSC3 09:40 Richard Out to End-Y 10:30 Scrap metal recycler on site to swap recycle bins 12:55 Cyrus At X-Arm spool area to terminate Cat-6 cables 13:15 Corey Out to End-X TMS lab to recover tools for End-Y 14:30 North Gate Electrical on site to deliver part
Removed gasket from 4.5" CFF blank on BSC9 (location of to be installed ESD interlock gauge) and left flange loose to exhaust wet purge air over the weekend -> Started QDP80 and Turbo -> Began pumping on BSC9 annulus
Safe.snap files were updated for every SEI platform involved in PRMI.
Soft links were checked, and safe.snap files were commited in the svn.
ISI
HAM2, HAM3 - r6572
BS, ITMY, ITMX, ETMX - r6576
HPI
HAM2, HAM3 -r6574
BS, ITMY, ITMX, ETMX - r6577
Every plateform involved was turned back on to its current optimal settings.
Below is a summary of the available controls on SEI platforms, for PRMI. Platforms should run under their preferred configuration at all time.
HAM1:
HAM2:
HAM3:
Note: The HEPI-BS position loops are in the second set of filter banks. One should use the isolate BS lv2 command button, instead of lv1, for this chamber only.
work of warning - the level 2 filters attempt to turn on Filter modules 2 and 3, and module 9 for boost (level 1 uses FM1 for isolation turn on + FM 10 for boost) one should check that the boost module is OK. It used to be true that attempting to turn on an empty module (FM3) makes no difference, but we should check... -Brian
A set of matlab transfer functions has been ran on the TMSX this afternoon after BSC9 was closed out, and while the ISI was damped. The pitch degree of freedom shows some excess noise between 0.7Hz and 3Hz, which is something I was not expecting to see since the measurement after the last work accomplished on TMSX was clean.
It might be related to some excess motion at the time of the measurement during the afternoon, which I will check by running undamped and damped TFs overnight in a quiter environment. We will see how repeatable the measurement is tomorrow morning.
It might also be the position of the cables that could have changed by themselves because of their weight. Or maybe some work that I'm not aware of that was done after the last measurement taken. In those cases we would probably need to physically check what is going on.
Results attached are described below :
(1) Comparison between the model and last TMSX TF
(2) Comparison between TMSX after the work done on Nov 20th (Orange trace), after the last time work has been done on Nov 22nd (black trace), and today (pink trace).
See the 5th page of (1) and (2) for the pitch dof
Looking at the new results from this morning, everything seems fine, and tf from overnight are not showing any problems. Plots pending.
In fact, after investigating a little bit more, and looking at the pitch motion at the suspension point of the TMSX, it looks like the ISI was moving in Pitch at low frequency during that measurement. The 3rd attached pdf shows in blue the pitch input motion during yesterday afternoon's TF (noisy measurement), and in green during the overnight TF.
The other two pdfs are showing the results with :
(1) a comparison between yesterday afternoon's TF and the one taken overnight
(2) a comparison between and LLO and LHO undamped TMSX tfs
Results are very clean and similar to model and LLO's data.
Hugh noticed that some HEPI ITMY slow channels were not correct in the DAQ. I did some investigation and found:
Of the slow channels (datarate=16) in H1ISIITMY.ini :
channels associated with the FEC were correct
channels associated with Filter Modules were correct
other slow channels were incorrect, either showing zero or other data (like channel hopping)
Fast channels appear to be OK (within the limited sample I used)
The problem is not seen with HEPI BS or ETMX. Looking at the models they all look identical.
Reboot/Restarts:
I first restarted h1hpiitmy. Then tried restarting all models on h1seib1. Then tried a restart of the mx-streamers. Then recompiled and reinstalled the h1hpiitmy model and restarted it, followed by a DAQ restart (DAQ status was good, so this should have been unnecessary). All to no avail.
The only thing I haven't done is reboot the computer.
It appears this problem appeared when we upgraded to RCG2.8 on Tue 12 November.
We'll have to look at those channels here at LLO (once I figure out which ones they are...). A contributing factor may be that mx_stream driver update was not explicitly listed in the RCG 2.8 upgrade instructions. There were changes from 2.7.2 (but none appear linked to 2.8). This driver can be updated now, but would require mx_stream restarts (or even front-end restarts to load new kernel image).
Celine has checked some of those channels here at LLO and is not seeing the same issue, either on MEDM screens or values on the DAQ.
[Jeff B, Andres R, Rich A, Jeff L, Koji A]
We successfully resolved the grouding issue of the OMC preamps, thanks to the help provided from Peter K, Rick S, and Betsy B
for the necessary isulating materials. Here is the note for ourselves and someone who may work on this insulation for L1 and 3IFO.
The grounding of the ISC cables were caused by the mounting of the preamps (attached figrue, left). The PEEK washers
were used to isolate the bracket from the structure. In order to fit the wahsers, we had to trim them (only for the outer one) with crimpers.
In order to isolate the 1/4-20 screws from the hole walls, we used Kapton tubes. Since the diameter of the tube was too big
for the hole, we had to open the tube and trim it to reduce the number of turns. In addition, the metal washers should have
been removed as they sneakily caused the grounding with the preamp.
Additional note (Dec 8)
The preamps are touching the cable for the PZT signals. Therefore the installation of the isolation kit should be done
without removing the adapter plate in order to avoid misalignment of the glass breadboard.
This can be done by installing the isolation kit one side at a time:
1. Loosen the two 1/4-20 caps
2. Remove one of the screws while the adapter plate was kept at the installed position.
3. Insert an unmodified PEEK washer between the SUS structure and the adapter plate.
4. Put a trimmed PEEK washer on a screw. Roll a kapton tube around the screw.
5. Insert the screw combo into the screw hole.
6. Turn the inserted screw (not fully)
7. Repeat 2 to 6 for the other screw
8. Tighten the two screw.
9. Check the isolation between the preamp housings and the SUS structure.
Arnaud and Kiwamu
We looked back the past data of the MC3 OSEMs. We found that the IOP DACkill had been triggered by MC3_T3 OSEM as it was hitting the open light value of 22000.