TITLE: 08/15 Day Shift: 15:00-23:00 UTC (08:00-16:00 PST), all times posted in UTC
STATE of H1: Aligning
INCOMING OPERATOR: Jeff
SHIFT SUMMARY: Commissioning work all day. HAM6 chamber manager is currently paused and the ISI is set to Robust Isolated.
LOG:
Am baking Vertex RGA whilst HAM6 pumps run this week. 1200 hrs. local -> Heating of Vertex RGA started
Comparison of Calibration Epics Values (Calibration parameters at t = t0) during O1 and ER9. Param. Description 2015/09/29 2016/08/03 2016/08/10 ---------------------------------------------------------------------------------------------------------
EP1 ~1/Atst0 (ftst) 2.2005e+16 2.1066e+16 4.9121e+17 EP2 ~Delta C/(1+G) 0.9895 0.9934 0.9934
EP3 1/Apu0 (fctrl) 2.1115e+16 2.1077e+16 2.1077e+16 EP4 Atst0 (fctrl) 5.4972e-17 5.6354e-17 5.6354e-17 EP5 Apu0 (fctrl) 4.7360e-17 4.7446e-17 4.7446e-17 EP6 Cres(fpcal2) 1.1307e+06 8.9859e+05 8.9859e+05
EP7 D0(fpcal2) 1.7599e+07 1.5871e+11 1.5871e+11 EP8 Atst0 (fpcal2) 1.2178e-18 1.13718e-18 1.13718e-18 EP9 Apu0 (fpcal2) 2.0898e-19 2.0235e-19 2.0235e-19
Kyle reported on Aug 12 that he thought there was a correlation between his RGA signal and locking attempts.
https://alog.ligo-wa.caltech.edu/aLOG/index.php?callRep=29079
On July 19 there was a programming change to the FPGAs;
https://alog.ligo-wa.caltech.edu/aLOG/index.php?callRep=28535
During this process there was a pressure burst in PT410 at the YEND. Dave believes that as the system was brought back, dacs railed while connected to the ISI. This caused all actuators in the chamber to go to their maximum output. We believe this caused some heating which resulted in the pressure bump.
Perhaps Kyle saw pressure changes related to ISI activity?
Dont forget to get work permits in today for work tomorrow. Let's try to make tomorrow a short maintenance day so comissioners can get to work early.
SEI - HAM6 will trip with often the shutter now. HAM6 now runs in Damped for the beginning of locking then then switched later but is a WIP. SDF will be red.
CS HEPI pump maintenance tomorrow.
SUS - HAM6 sus look good.
CDS - ISS outer loop work, FRS work.
New version of GDS code (DTT updates).
PSL - PSL seems good. TCS has CO2 laser swap planned (Alastair on his way). BS OpLev investigation.
Vac - Fire up pump to bake out RGA at vertex, Yend worked well. A couple of days of pumping for HAM6
Facilites - LED lights along walkway need to be coiled up (broken?)
Ran through work permits.
Julia Kruck and I buried the high-sensitivity LEMI magnetometers this week near the vault. This is at the approximate location for which trial spectra were taken (https://alog.ligo-wa.caltech.edu/aLOG/index.php?callRep=12525), and determined to be good enough to study subtraction of the effects of globally correlated fields due to, for example, Schumann resonances.
We buried them directly in the soil at a depth of about 18 inches. We used a bubble level to ensure that they were not tilted in Z, and aligned them with beam tube X and Y using lines constructed and measured on Google satellite images. We think that this alignment technique was more accurate than could be made with the simple compass that we had, though we made sure that the compass agreed with our alignment. The connector to the X-axis magnetometer is 17m in the -X-direction from the +Y corner of the electronics vault, and the magnetometer extends in the -X direction beyond the connector (see photos). The Y-axis magnetometer has its connector 1.22 meters +X and 1.22 m -Y of the connector for the X-axis magnetometer, so the closest parts of the magnetometers, the connectors, are 1.72 m apart. The connector is on the +X or +Y end of the magnetometers so that the signals will have the proper phase relationship. 1.22 meters of cable is buried directly in the ground before the point where the cables come together to enter the conduit (yet to be installed) in order to damp any cable vibrations. The LEMIs lie between the lines of orange stakes that parallel them to either side (see photos). The electronics had not arrived so they have not yet been tested.
Absolute location: X-axis magnetometer is 1020 m +X, 188 m +Y of the vertex
Robert Schofield, Julia Kruck
Evan, Sheila
This morning we had truoble with DRMI ASC. THere are a few things that seem to have helped (in addition to intal alingment and some by hand alignment), and how the guardain is reliably getting to analog CARM.
Currently we are in a similiar situation as the last two nights, we can lock the interferometer but loose lock within a few minutes. We have lost lock even while sitting on analog carm, we have been able to switch PRCL and MICH to POP sensors but suddenly lost lock about a minute latter.
The sudden locklosses seem to happen only after switching the CARM sensor to REFL9 (the digital or analog version). We can set at 5 pm CARM offset seemingly indefinitely, but any full-resonance lock (after the sensor is switched to REFL9) is a few minutes or less.
The LSC OLTFs (including the digital CARM) all look fine on resonance --- no evidence of loop instability. Debugging REFL9 seems like the next logical step.
There are a few things that still needed worktonight with the fast shutter, and will need more work:
A few other things:
The ISS diffracted power has been at around 4% since August 2nd (the first day of the vent). Before the vent it was around 16%, but DIAG_MAIN thinks the diffracted power should be between 1 and 6%. I moved it up to about 14%, so DIAG main is complaining.
There is a problem with switching DRMI to POP signals in full lock. We can stay locked stably for ~10 minutes at ANALOG CARM, but lose it shortly after transitioning DRMI to POP signals each time. Before transitioning off the 3F signals, the MICH UGF is about 5 Hz. I manually changed the digital gain from 1.4 to 3.6 to restore the loop to a 10 Hz ugf, although I don't know why the gain would be low. The PRCL and SRCL UGFs were normal. After adjusting the MICH UGF I was able to transition to POP, but did this in the middle of an earthquake. I don't know if the lockloss about a minute latter was due to the DRMI problem or due to the earthquake.
Regarding the ISS diffracted power, on August 2nd we re-calibrated the percentage diffracted power display; see the 4th paragraph of Peter's August 2nd alog here. Previous to this the ISS diffracted power percentage was displayed incorrectly, so when the display said 16% in reality it was diffracting around 2-3%. We want the ISS diffracted percentage to be around 3-4%, which results in ~6W diffracted by the AOM; at 14% the AOM is diffracting ~24W, which is much more than necessary. This change was discussed in the 8:30am meeting on August 3rd and DIAG_MAIN must have been updated to reflect this new ISS diffracted % value (I'm assuming this is the case, as I can't find an alog detailing this change to DIAG_MAIN). Please set it back to around 3-4% (I believe this is a reference signal value somewhere in the neighborhood of -1.70V).
Thanks Jason. I've reset the Ref Signal to -1.7 which gives a diffracted power of 3.2%
Our DRMI lock times have been a little long in the last 2 days, it seems like the beam splitter optical lever is glitching. The attached screenshot shows a PRMI lock where the BS oplev damping is on for the first minute, you can glitches in both POP90 and POP18, when the oplev damping gain is ramped to 0 the glitches go away although there are some oscillations in the build up. Turning the oplev back on brings back the glitches.
The BS oplev was getting worse and making locking worse, so we went to the floor and adjusted the knob a little but (about 1/10 th of a turn clockwise). It seems to be better but is probably worth checking on tuesday.
After decoupling the pumping components used during the recent bake out of the Y-end RGA, I exposed the RGA to the Y-end vacuum volume, energized the filament and let it come into equilibrium for an hour or more. I then let the RGA scan continuously with the multiplier (SEM) on for an additional hour or so while I gathered up my mess(es). I periodically checked the scanning as I walked past the screen. At one point, I noticed that the spectrum was changing rapidly towards the "dirty". I monitored the scanning and noted that after reaching a temporary maximum, the amus which had increased then returned to near their original values. After consulting with the Jeff B. (the operator on shift), I feel that the observed changes in partial pressures were likely the result of IFO locking attempts as they coincide closely in time. Perhaps something gets hot when the IFO is locked or when mirrors are steered? See attached scans
If true that could be kind of scary (!) Can we set an RGA in MID (stripchart) mode and run time series following the main peaks through a locking attempt?
I could imagine baking the adsorbed water off the ETM and perhaps nearby baffles. But this should not persist (or repeat) after the first good cavity buildup.
Mike - Chandra's stated goal is to eventually continuously trend 7 AMUs (max allowed by software) at each building. The observance cited in this aLOG obviously would have been missed while in Faraday. Too bad that the RGAs don't live long with their SEMs on 24/7. As we install/commission the RGAs and as she works out the issues with the CDS and/or GC folks this trending will eventually be happening. J. Smith - The partial pressures that are changing are too small and not expected to show up on the total pressure gauges. From the graphic scans and knowing that the total pressure at the Y-end is 2 x 10-9 torr, we see that the partial pressures that changed are small (10-12 torr) - but still interesting because they are measurable and even more interesting if the changes can be shown to be tied to some IFO locking activity. (Science interesting? Who knew?)
Doh!!! Here are the .txt versions of the ASCII data
The indicated currents for these scans are typical of the SEM @ 1300 volts (which is the factory default). I have noticed in the past that setting the SEM voltage value in the EDIT tab does not change the value displayed in the device status screen or vice versa - so, though I set this to 1500 volts in one of those two fields, it may not have taken effect.
The attached is just one instance and is fairly representative of the trips. Most of the time, the ACTuator is called to blame, but as I reported in 29056, I'm not sure the Last Trip is absolutely robust.
The 2 seconds of full data show the ISI in Full Isolation (GRD STATE) when Stefan throws the shutter (FASTSHUTTER A MODE.) You can see a fraction of a second later, the Actuator MASTER DRIVEs going very large. All the actuators are contributing to the saturation counting as the threshold is only 32760 counts. The watch dog trips near the end of the two seconds (WD MON STATE.) It was going to happen anyway but I can't be sure why the WD tripped because none of the counters (iii SAT COUNT) actually reached the trip threshold. This is a mystery to me, still. The SAFE COUNT is 8192, 4096, and 10 for the ACT, GS13, and CPS. None of the counters reach the SAFE COUNT level.... Regardless, the Actuators where going to reach it so that is another problem to figure out.
Unless the shutter softens its blow on the ISI, the trips are going to happen almost everytime. For now, we are running with HAM6 in the DAMPED state. There the HAM6 sees a few saturations on the GS13s when the Shutter triggers but literally just a few. The HAM6 will be transitioned to ISOLATED by the ISC after the FAST SHUTTER is tested.
We could have the HAM6 ISI in damped while we are testing the shutter, but we want it to beisolated when we are running the IFO, so when we loose lock and the shutter triggers we will stil be frequently tripping the ISI.
In an effort to eliminate the need to connect and disconnect shutter cables during vent we have moved the shutter logic controler to the rack from the table. Also replaced the BNC cables with Yellow BNC cables so they can be easily identified. See attachment.
Evan H., Darkhan T.,
Details
SUS-ETMY_LKIN_P
(see LHO alog 28164). Later we found that the amplitude of this line in the DARM spectrum recorded during ER9) was unsufficient for tracking the ESD actuation strength. So, the EPICS values for time-dependendent factors were recalculated on Aug 10 for using a calibration line injected fromSUS-ETMY_L3_CAL_LINE
.The transfer function for the
SUS-ETMY_L3_CAL_LINE
line includesDRIVE_ALIGN
filter, which is not the case for a line injected fromSUS-ETMY_LKIN_P
. The gain of this filter at cal. line frequency is ~22, this explainsEP1
value change.EP6
).EP7
(D0 at 331.9 Hz), could be that during ER9 we, by mistake, did not turn on the notch at 331.9 Hz. In O1 run this notch was inLSC-DARM
, FM7 (see LHO alog 20075). After adding a second set of filter modules (nowLSC-DARM1
andLSC-DARM2
) the notch was moved toLSC-DARM2
, FM4, but was not turned on during ER9.Note:
LSC-DARM2
, FM4 will be turned on during nominal low-noise operation in ER10/O2 (must not forget to include this into Matlab DARM model).