Den, Patrick, Evan
During IX coil driver investigations yesterday, we rang up some violin modes to very high amplitude (~4×10−14 m rms in DARM, about 4 orders of magnitude higher than our optimal, damped mode height).
The existing violin mode damping settings, which consisted of a few wide filters meant to actuate on multiple modes simultaneously, were damping some of the modes while causing others to ring up.
This is not the first time we have been hoist with our own wide-bandwidth pitard. Additionally, we have more the enough filter modules per test mass to damp each first harmonic individually, which alleviates the problem of having to find a filter to damp multiple modes simultaneously.
There were five IX modes visible in DARM on rf readout. For these five modes, we constructed narrow, individual damping filters (8th order butterworths). The settings are as follows:
Freq. [Hz] | FWHM [mHz] | Phase | Gain [ct/ct] |
500.054 | 100 | 60° | 100 |
500.212 | 100 | 0° | 100 |
501.208 | 30 | 0° | −10 |
501.256 | 30 | 0° | 10 |
501.452 | 100 | 0° | 100 |
Note the narrow bandwidth of the filters for the two 501.2 Hz modes.
These use the IX L2 damping SFMs, numbers 1 through 5. The corresponding OAF monitor filters have been updated as well.
That means there are three other first harmonics on IX that are yet to be damped.
I have increased the CO2 Y laser from 0 to 110 mW as a part of the tuning of the differential lensing. No obvious imporvements or degradation were observed so far.
I am leaving CO2 Y as it is. If this setting turns out to make some noise performance worse, one can feel free to decrease the power.
[Background]
We have three tests/adjustments to do in this week and perhaps the coming as follows:
This alog reports an activity related to the first topic. The work has not been concluded yet. So we need to return to this point at some point.
[RF9 3rd HOM?]
There was a theory that the differential heating may be efficiently sensed by monitoring a 3rd order HOM of the 9 MHz rf sidebands. We obtainted this idea from a measurement that Dan did a while ago (alog 22175). However, according to today's test with PSL at 2W, this theory does not look promising. We should repeat this at 20 W.
[The test]
I have increased CO2Y from 0 to 110 mW. According to Aidan's simulator (alog 25587), this introduces a defocus of about 6 uD. Also, from the experience on this Monday, 400 mW of CO2 Y makes some part of the interferometer unstable and eventually unlocks. So this time, I chose 100 mW.
The interferometer stayed locked with AS RF45 Q with a nominal DARM offset (a few 10 pm) throughout the test. The PSL power was at 2 W. The OMC alignment was first optimized by engaging the length and dither alignment loops then I updated the QPD loops' operating points. I unlocked the OMC and changed the PZT voltage until I found the 3rd order HOM of RF9. The alignment was servoed bt the QPD loops. The 3rd order HOM was as high as 0.1 mA while the carrier was about 20 mA in OMC DCPD SUM. I wanted to lock on the HOM but unfortunately this was not practical. As the alignment chnages the peak height of this particular mode changes and also there was a 2nd order HOM of RF45 which is more stable and high. So for these reasons, the loop was not stable. I instead decided not to lock the OMC length and continuously adjust the pzt voltage by hand every few minutes or so. By the way, this mode was able to increase its power by a factor of 3 by changing the OMC alignment. Not great.
The attached trend shows some relavant channels over 1 hour. I do not see any obvious change in the carrier power (i.e. TRX, TRY and REFL_LF). The RF9 3rd HOM stayed constant throughout the test which is visible in OMC DCPD SUM since the OMC length was set such that it resonates with this mode. There was a slight change in POP RF18 which slightly increased by 6% or so with some amount of rf phase rotation. The interferometer stayed locked throughout the test. I have done a OMC scan after and before the test. I will process the data and post the results later.
Ideally, I should have monitored the laser noise couplings at the same time, but I did not do that this time. So, perhhaps next time.
15:56 UTC Bubba to LVEA to work on crane. 16:13 UTC Took ISC_LOCK guardian to down. Paused ALIGN_IFO guardian. Put guardian for each optic in HAM2 to SAFE. 16:15 UTC Richard powering down SAT amps for optics in HAM2. 17:11 UTC Richard done. Started relocking. 17:17 UTC Bubba done. 18:22 UTC Nutsinee to mechanical room to check TCS cable width. 18:29 UTC Nutsinee done. 21:21 UTC Sheila and Keita to racks near HAM6 to look at PZT voltages. 23:17 UTC Kyle to mid Y to fill CP3. 23:35 UTC Kyle back. Support: Sheila, Kiwamu IFO locked at NLN upon arrival. Took ISC_LOCK to down and put HAM2 suspensions in safe mode to allow powering down satellite amps for capacitor fix. Repeated lock losses at FIND_IR during recovery. ETMX HEPI tripped (see Jim W.'s alog). Ran through initial alignment after trouble locking DRMI. Left locked at ENGAGE_ASC_PART3 as requested by Kiwamu. Evan H. working on violin mode damping.
1517 - 1532 hrs. local -> To and from Y-mid LN2 at exhaust 40 seconds after 1/2 turn open. Next overfill to be Friday, Feb. 26th. before 4:00 pm local.
The beam tube cleaning crew departed for LLO this morning to help out down there. The beam tube cleaning will be on hold until they return. The crew should be back at LHO on 03/07/2016.
This morning ETMX HEPI tripped again after a lock loss. Sheila and I looked into it and it looks like there is some difference between the tidal controls between the two arms. The first screen shows a number of signals related to the X arm tidal. After the lockloss (where the TRX power green(?) trace goes to zero in the center left) HEPI starts bleeding off the tidal offset. It looks like some flash makes the ALS think the arm is locked again, and it sends an 80 micron kick to the HEPI ISC offload (the big downward jump in the red trace, bottom left). The next two, traces are the request and states for the ALS X and Y for 5 seconds around the time of the HEPI trip. The second screen shows the state and request for Y, the notch in the black trace is the lock loss. The red trace shows the request going from (I think) Locked to Transition to Down (or something like that). The third screen shows the same time for the X arm. The state goes from Locked to Down, then 2 seconds later the Request goes from Locked to Down, which cause the State to jump back up to Locked, then immediately back to Down. This jump lines up with the big kick to the EX HEPI that causes the trip.
Updated the tidal code to add a 5s delay before engaging. Still needs to be activated.
200 ml added. This seems to be about 50 ml too much. The water level is beyond MAX line but not overflow.
FAMIS#4139 closed
TITLE: 2/24 eve Shift: 00:00-08:00 UTC (16:00-00:00 PST), all times posted in UTC
STATE of H1: Planned Engineering
OUTGOING OPERATOR: None
QUICK SUMMARY: Commissioning work for the entire shift. Letting the WFS settle at DRMI and Locking_Arms green, seemed to help things lock.
To try an combat the rising secondary microseism, we changed the ends to the 45mHz blends to match the CS.
We lowered the DARM gain by a factor of 2 when we transition from ALS DIFF to AS45Q, we had some gain peaking around 90 Hz that was causing locklosses. This has reduced the RMS drive to ETMX L3 from nearly 100000 cnts to about 20000 snts in this state.
Added 296 channels. Removed 8 channels. (changes attached)
(Keita Daniel)
We installed the amplitude stabilized RF EOM driver in the PSL. In the process the phase of the 9.1MHz modulation signal flipped by 179.3°. The measured RF power was 16.7dBm which requires H1:LSC-MOD_RF9_AM_RFSET to be set to 16.8dB.
The new controls/DAQ cables were used for both the 9.1MHz and 45.5MHz units. For the 9.1MHz unit we are using H1:ISC-430 (DB9/DAQ) and H1:ISC-432 (DB25/ctrl), whereas the 45.5MHz unit is using H1:ISC-431 (DAQ) and H1:ISC-433 (ctrl), respectively. The old cables have been pulled out of the PSL enclosure.
The RF readbacks of the 9.1MHz are currently shwoing around 18.3dBm. This is a calibration error which needs to be corrected in TwinCAT.
(All time in UTC)
15:20 Chris S. to X-arm (150 yards from corner station)
16:04 Jeff B. to Y end (Test Dust Monitor)
16:17 Let pest control in
16:30 Transitioned LVEA to LASER SAFE. Bubba to LVEA.
16:35 Joe escorting pest control through LVEA and VEAs.
16:37 Richard + Calos was up on the roof, not anymore (WP5743)
16:50 Hugh to both end stations (HEPI pump maintenance)
17:00 GRB/Supernova alarm
17:07 Brought MC1 and MC3 to SAFE for Richard's work
17:15 Bubba out of LVEA
17:29 Carlos rebooting NUC machines
17:30 Jim rebooting Guardian machine
17:42 Rick to PSL enclosure
17:47 Hugh back
Let Hanford fire dept. in -- to X arm
17:52 Richard going on the roof
Guardian restart seems to be completed but all the HPI have 'CODE ERROR'. Can't be cleared with LOAD or by restarting Guardian.
18:02 Joe and pest control done in all the VEAs.
18:10 Another Hanford fire dept. came to do some testing.
18:19 Jeff B. back from EX
18:27 Rick left the laser room in the "commissioning" mode
18:30 PRM, PR3 to SAFE. Put MC1 and MC3 back to SAFE.
Bubba closing GV5, GV7 for heavy crane work.
18:38 Richard back to LVEA
18:43 Rick done
18:49 Dave restarting ISC node Guardian
19:06 Dick to Electronics rack by PSL.
19:41 Dave rebooting Guardian machine
19:53 Dave done
Bubba out of the LVEA. GVs are opened.
19:54 Pest control done everywhere.
20:25 Keita and Daniel out of PSL. Going back after lunch.
20:40 Richard done for now. Put PRM, PR3, MC1 and MC3 back to ALIGNED
20:47 Let another fire dept. in.
21:03 Karen and Christina back to LVEA + open rollup door.
21:04 More fire dept. in. Joe taking them to EX and EY.
21:05 Keita's going back to the floor.
21:22 Richard going back out on the floor. Putting PR3, IM1, IM2, IM3, IM4 to SAFE
21:29 Bubba out to do more crane work.
22:39 Bubba out.
22:55 Richard done.
23:22 Let a delivery truck in And sent them back out to LSB.
23:58 Joe done escorting fire dept at VEAs.
00:00 IM3 WD tripped. After untripped there's no counts going out. Richard is working on it. Hand off to TJ
Replaced our aging NTP server with an new unit that has the ability to provide more protocols. New Antenna on roof also.
Per work permit 5741 began the process of modifying all Suspension Satellite Amplifiers. Drawing D0901284-v4 calls for the addition of Cap C601(10uF) and C602 (.1uF) between the -17V to Ground around U503 the Negative Regulator VEE1. Today with Ed M. Soldering away in the lab we were able to complete all of Han2 units. Complete are: MC1, MC3, PRM, PR3, MMT1, MMT2, SM1, SM2 All Stages. We did have a problem with two Sat Amps. One shared between MC1 and MC3 and the one for MMT2,a trace blew when it was powered up. So replaced SN 1100117 with SN S1000287 and SN1100068 with SN1100066.
Tracking Names: SM1 = IM1, PMMT1 (MMT1) = IM2, PMMT2 (MMT2) = IM3, SM2 = IM4
UPDATE:
As of today all HAM3, HAM4 and EX Amps have been modified. HAM2 amps will have to be re-addressed due to an error in installation of the mod. 3IFO boxes are in process.
- Ed
Peter Shawhan, Carlos, Jim, Dave:
FRS4412, WP5740
Summary of problem, IERS (international earth rotation and reference systems) web page which announces future leap seconds addtions to UTC (called the Bulletin C page http://www.iers.org/SharedDocs/News/EN/BulletinC.html) was being accessed by LHO CDS several times per second.
We had two problems: h1hwinj1 machine accessing the web page every 10 seconds, h1guardian0 machine accessing the web page on average several times per second. In both cases it was a non-bash-shell process calling the tconvert program.
tcleaps.txt data file
A new location outside of the apps area is now used to hold the tcleaps.txt datafile which provides tconvert with the history of leap seconds. The new location is /ligo/data/tcleaps/tcleaps.txt. This directory is referenced by the environment variable TCLEAPSDIR.
h1hwinj1:
Fix was to change the standard environment as defined by the files /ligo/cdscfg/lho/h1/stddir_linux.sh and stdrc_linux.sh. Rebooted h1hwinj1 machine.
h1guardian0:
Guardian nodes call tconvert via the cdsutils-gpstime utility. Fix was to change /ligo/apps/linux-x86_64/cdsutils/etc/cdsutils-user-env.sh. Rebooted h1guardian0 machine.
Verification:
Before and after the changes we ran tcpdump on the main CDS NAT router to verify web access to the Bulletin C page went from several per second to zero. During normal operation, this web page should only be accessed twice a year.
This morning I closed GV 5 & 7 so I could crane the snorkel lift over the Y beam tube in the LVEA. Valve closure and opening times are as follows: GV5 closed @ 10:34 PT GV7 closed @ 10:36 PT. GV 5 opened @ 11:24 PT and GV 7 opened @ 11:26 PT.
Attached are 7 day pitch, yaw, and sum trends for all active H1 optical levers. Closing FAMIS #4393.
Notes:
Everything here looks good. We need to keep an eye on the HAM2 oplev (assuming anyone is actually using it), it is getting close to the edge of its linear operating range (~±30 µrad).
We'll keep an eye on ETMy yaw as well. Its linear operating range is large (on the order of ±50 µrad) so a re-zeroing is strictly necessary, but it is used for weekly SUS charge measurements so a tighter operating range might be desirable.
Den, Sheila, Evan
~> We tried reverting to the old QPD offsets (the ones we used throughout O1) for the soft loops and the PRM pointing loops. These seemed to make the recycling gain slightly worse, and did not improve the jitter coupling. This indicates that (as we had suspected) these offsets are no longer good to use.
~> We measured the 9 MHz oscillator phase noise coupling into DARM. This had been done previously (19911), but with a suspicious calibration and in a way that also drove the 45 MHz phase. This time, we used the OCXO to drive both the harmonic generator (bypassing the 9 MHz distribution amplifier) and to serve as a reference for an IFR/OCXO PLL with a >40 kHz bandwidth. The IFR is used to drive the 9 MHz distribution amplifier. The error point of the PLL was offset in order to maintain the relative time delay of the 9 MHz and 45 MHz signals. When we relocked, we found that the 18 MHz and 27 MHz signals had flipped sign, but otherwise the interferometer locked normally. However, there was a great excess of 45 MHz noise in DARM (worse even than before we installed the 9 MHz bandpass). Nevertheless, we were able to drive enough to see the effect of 9 MHz phase modulation in DARM. The coupling is roughly 2–4×10−6 mA/Hz above 100 Hz.
Also, twice last night (while locked on the IFR) we were battling a 900 Hz line in DARM that increased over the duration of the lock, and eventually caused EY to saturate.
We suspected PI, but this line was also present at 900 Hz in the DCPD IOP channels. So it is not folding around the 8 kHz Nyquist of the digital downsampling.
This line does not appear in the IOP channels for the end station QPDs. (2 W, dc readout)
It's the third harmonic of the beamsplitter violin mode. Den added a stopband filter to the BS M2 length drive, and the line went down.
Unclear why this had not been a problem before.
The damping phase of the mode at 501.208 Hz seems to have flipped sign at the start of the most recent lock. We'll have to keep an eye on this one.