Got the IFO to lock at high power (@ 23W) for about 3 minutes before Lockloss. Winds are in the high teens to low 20MPH. Will bring the IFO to DC-Readout and then adjust the power up manually.
07:53 Christina opening OSB receiving rollup door
08:00 Peter to H2 PSL enclosure (WP 5233)
08:00 Karen and Christina to mid and end stations to clean
08:08 Jodi moving 3 boxes of TCS equipment in LVEA
08:12 Richard to end X to replace wireless router (WP 5236)
08:26 Bubba checking on RO alarm, then replacing nitrogen regulators on LTS containers in LVEA (WP 5238)
08:31 Jodi back
08:31 Richard called from end X to test phone
08:39 Jodi to mid X to look for mirror
08:43 Joe to LVEA to flush eyewash stations, put water in lift trucks, etc.
08:49 Filiberto to end Y to test cabling (WP 5103)
08:52 Peter done
08:58 Richard back
09:01 Jodi back
09:05 Jodi, Nutsinee to LVEA to get viewport guards
09:18 Karen, Christina leaving end Y, going to mid X then end X.
09:25 Jodi and Nutsinee back
09:39 Kyle to end Y to turn RGA bakeout on, then end X to run up turbo (WP 5237)
09:40 Mitchel going to mid and end stations (not VEAs) to get serial numbers
09:40 Joe back
Jim B., Dave pulling fibers under floor tiles
09:55 Karen and Christina leaving mid X, going to end X
09:56 Hugh checking HEPI fluid reservior levels
09:58 Filiberto back
10:06 Bubba back
10:08 Nutsinee and Rick taking pictures of ETMX (WP 5240)
10:20 Joe back to continue previous work in LVEA
10:26 Dave updating h1calcs model (WP 5241)
10:26 Bubba pulling tubing for TMDS
10:27 Karen and Christina leaving end X
10:36 Jim B. done with floor tiles
10:50 Dave, Jeff K. restarting h1sush34 IO chassis for 18 bit dac recalibration
10:59 Joe back
11:09 Hugh back
11:10 Nutsinee and Rick done
11:25 Karen and Christina to LVEA to clean
11:26 Jeff K. restarting h1calcs model
11:32 Kingsoft water through gate, notified Bubba (WP 5239)
11:35 Mitchell back
11:37 Restart of guardian machine
11:54 Karen and Christina out of LVEA, opening OSB receiving rollup door to empty cardboard container
12:10 Pepsi truck through gate
13:28 Kyle done
Karen and Christina report that the phone is not working at mid Y.
Kyle reports that a set of cables is pushed against a pyramid shaped pier at end Y.
Cheryl, Evan, Kiwamu, Patrick, Sheila
Had trouble running through an initial alignment after maintenance. It turned out that the safe.snap files used for h1sush34 had the gains set to 0 for the inputs to MC2 and PR2. We changed these back to 1 by hand. The safe.snap files will need to be fixed.
Sheila enabled optical lever DC alignment feedback on SR3. (alog 18777)
We had trouble getting past the RESONANCE state. We stopped in the CARM_5PM state and Cheryl adjusted the alignment of one of the power recycling mirrors. After this we were able to lock twice on LSC_FF.
After today's reboot of h1guardian0, its load averages are staying in the 6-7 range. We'll see if it ratchets back up as it has done in the past month (see plot).
Duncan, Dave
I installed Duncan's latest version of cal/common/scripts/ext_alert.py and started running it as user controls on h1fescript0 at 15:36PDT. It has been running for an hour so far with no problems, and correclty reported the FERMI GRB event from 20:09UTC (13:09PDT).
You can view the GRB information in the "Latest astrophysical event alert" section of the CAL_INJ_CONTROL MEDM screen, accessible from the SITEMAP via the corner station CAL pull down, "HWINJ CTRL" option.
To view recent GRB events from the LIGO GraceDB database, follow this link
https://gracedb.ligo.org/latest
and Query on the string "External"
All of the SDF monitors are now cleared (show no diffs) except the SUS SR3. As stated in alog 18777 SR3 has optical lever feedback enabled for stability purposes. Since this is new we will keep it on the DIFF list until it proves itself helpful. See attached for snapshot of the 2 OK DIFFs on SR3. OPS will need to open the TABLE in order to see that these 2 DIFFs are the same as the snapshot, and no more, no less.
During the cleaning house, we also updated the comparison snap files on SDFs of the following since there were models/database changes made over the last month+:
IOPSUSEX
IOPSUSEY
IOPSEIH16
OMC
OAF
SudarshanK, DarkhanT
To keep the things similar between LHO and LLO for ER7, the displacement calibration coefficient (volt to meter conversion factor) on Pcal main read out channels TX_PD _OUT and RX_PD_OUT are switched off. The calibration coeffcient for each channel, if needed, can be found at DCC #1500252. These channels will be recorded to the frames in volts for now.
This is work I completed a while ago (the 7th of May if Matlab is to be believed), but I wanted to put this in for comparison with my log 18453. These are the new (as of May 7th) and old isolation filters for ETMY. ETM's are definitely harder to do that ITM's, but loops should be very similar now on all BSC chambers
That is a lot of gain peaking in X and Y (7 and 4.6 for St1 * 4.2 for stage 2, so ~30 and20 over all) worth remembering if there is a problem later on
Dave created a dummy target area where I stuck an autoBurt.req file which will start capturing all of the SUS alignment offsets on the auto-hourly basis. This will aid in realignment after a Tuesday set of reboots. (Recall, the reboots usually preceed a burt restore which often houses old alignment offset values. - And the age of each restore file is different so the alignment settings are from a variety of alignments, not a matched set. Therefore, we have been having to perform major realignments after Tues maintance, such as today.)
In the future - find and restore the latest locked good alignment from the hourly backups in:
/ligo/cds/lho/h1/burt/2015
under the appropriate date /h1ifoalignepics.snap
For ASC modelers, here are screenshots of our matrices in full lock.
Nutsinee, Pat Meyers, Marissa
In the recent LHO locks, we've noticed a line in DARM that wanders around between ~410-420 Hz, consistently appearing in every lock from May 13th to the present. For example, here is a spectrogram of 2 hours from May 15.
There is a peak around that frequency in the Rayleigh plot (This plot shows the standard deviation of the PSD divided by the mean in each frequency bin. For a random Poisson-distributed signal, this ratio should be one.) For example, the Rayleigh plot from May 15 shows this peak, and going back through the summary pages, this non-stationarity in the spectrum appears to have been there since May 13.
Looking further back, we saw that there was a wandering line around the same frequency in the March 27th lock, but its frequency drifted much more slowly; see this 2 hour spectrogram.
Pat has used STAMP-PEM to look for coherence with other channels but hasn't found any obvious culprit. We've also made spectrograms of many other channels, including MICH, PRCL, and SRCL, which don't show the same line.
Nutsinee also did some follow-up to see if this was the same as the "seismic bumbling line" from ETMX (see alog 17681), but found that it is quite different. For example, compare the DARM spectrogram with this 2 hour ETMX spectrogram from May 15 (at the same time as the spectrogram shown above for DARM). At this time, the seismic line wanders between 200 and 240 Hz, with no obvious correlations with the DARM wandering line.
This line (as well as other ones at 166, 235, 250 and 970 Hz) is not new, it was there on a lock on March 25th, see 17464
J. Kissel, J. Betzwieser Joe had uncovered a particularly nasty bug in the wiring of the CAL-CS front end model's reproduction of the digital actuation chain in the SUS (see LHO aLOG 18465). He's committed a bug fix, I've svn up'd and recompiled, reinstalled, restarted, and restored the front end code with the new fix. Details: -------- As you know, in the suspensions, one has the ability to choose between a distributed and offloaded hierarchy for the actuation. In the CAL-CS model, a stripped-down, longitudinal-only version of this hierarchy option has been installed such that we can exactly replicate what's been installed in the actual SUS hierarchy for the DARM / DELTA L calibration. As Joe says, "At some point the tag coming from the LOCK_L3 output (shown in magenta) and the L3_ISCINF output (shown in orange) had been switched" which causes indescribably confusing things to happen with the hierarchical control (at least not without a serious exercise in loop math). The two attachments show the before and after. Yikes! Good catch Joe!
To run timing slaves in the EE shop, a fiber was pulled from port 8 on the MSR timing master to EE.
WP 5219 Pulled excess multimode fiber cable from computer user's room (CUR) to MSR to allow them to be connected to the patch panel in the MSR. The fibers had previously been pulled but did not reach as far as the patch panel, with the excess being coiled up in the CUR. Connected DAQ test stand network switch to MSR using multimode fiber, then to CUR to extend the DTS network allowing a DTS workstation to be used in the CUR. Also pulled one multimode fiber between the CUR and the timing master fanout rack to allow extending timing to the EE shop for timing component testing. Note that this fiber will not be connected to the master fanout until it is needed.
Wasn't able to test set point interlock functionality (maybe next maintenance day?)
Several front ends had partially loaded filter modules. To prepare H1 for ER7 data taking, I ran a script which pressed all LOAD_NEW_COEFF buttons on every model. I'll periodically "load all filters" if we encounter any partially loaded files during ER7.
after doing this I noticed that three filters in the LSC were being regularly reloaded. Evan tracked this down to the ALIGN_IFO.py guardian which was incorrectly writing a 1 to the RSET PV rather than 2 (load coefficients rather than clear history). This was fixed.
Daniel and I looked at three of the locklosses from Travis's shift last night, from 14:40, 14:02 and 11:33 UTC. The earlier two both seem to be related to an alignment drift over 2-3 minutes before the lockloss, which shows up clearly in SR3 PIT. (there is currently not feedback to SR3 PIT) According to the witness sensors, this drift is only seen on M3. No optics saturated until after the lockloss. The DC4 centering loop, as well as both of the SRC alignment loops respond to the drift.
Its unclear what causes the drift to accelerate in the minutes before the lockloss. There is also a drfit of SR3 when we power up, as we noted yesterday, but this happens on a slower timescale than the dirfts that preceed a lockloss (3rd screenshot). Also, there is a longer, slow drift that happens whenever we are locked.
With Patrick and Cheryl I have engaged a DC coupled optical lever for SR3 PIT, we will see if this helps. The last screen shot attached shows the MEDM screen used to turn this on or off.
If the operators need to disable this (due to an earthquake, a trip, or if the optic becomes misalinged for any other reason) you can get to this screen from SR3, M2 OLDAMP.
Turning off:
turn off FM1 (labeled DC), then the input
Turning it back on:
Once the optic has settled and the beam is back on the oplev QPD, turn on the damping loop (with FM1 still off). Average INMON (in a command line tdsavg 10 H1:SUS-SR3_M2_OLDAMP_P_INMON), type -1 times the average into the offset, make sure the offset is engaged, and finally turn on FM1 to make the loop DC coupled.
Since this is just a trial, Jeff is not including these changes in his current SDF cleanup campaign.
Looking at the initial power up, we can see that an increase of a factor of ~10 causes ~0.7 µrad of pitch misalignment. During the accelerated drift in the last 3-5 minutes before the lock loss another 0.4 µrad of pitch misalignment was acquired with only ~10% of power increase. One might wonder, if we see a geometrically induced wire heating run away.
I modeled how much the two front wires have to heat up to casue a bottom mass pitch of 1 microradian. A very small temperature increase is needed to predict this.
* Assuming a constant temperature profile along the wire length (I'm sure this is not the case, but it is easy to calculate), it is
0.003 [C]
* Assuming a linear temperature profile where with the max temperature is in the middle, and the ends of the wire have no temperature increase
0.006 [C]
So we can say an order of magnitude estimate is greater than 1 mC / urad and less than 10 mC / urad.
Calculations:
From gwinc, the thermal coefficient of expansion for C70 steel wire is
alpha = 12e-6 [1/C].
From the HLTS model at ../SusSVN/sus/trunk/Common/MatlabTools/TripleModel_Production/hltsopt_wire.m
wire length L = 0.255 [m]
front-back wire spacing s = 0.01 [m]
The change in wire length for pitch = 1 urad is then
dL = s * pitch = 0.01 * 1e-6 = 1e-8 [m]
* For uniform wire heating of dT, this change comes from
dL = alpha * L * dT
So, solving for dT
dT = dL / (alpha * L) = 1e-8 / ( 12e-6 * 0.255 ) = 0.0033 [C]
* For a linear temperature increase profile (max at middle, 0 at ends), I break the wire into many constant temperature segments of length Lsegment.
The temperature increase profile is a vector defined by
dT = dTmax * TempPrile
where TempProfile is a vector of the normalized shape of the temperature prodile. It is triangular, 0 at the ends and 1 at the peak in the middle. Each element of the vector corresponds to a constant temperature segment of the wire. dTmax is a scalar representing the maximum temeprature increase at the middle of the wire.
The change in wire length is then given by
dL = sum( alpha * Lsegment * TempProfile ) * dTmax
solving for dTmax
dTmax = dL / sum( alpha * Lsegment * TempProfile )
with 101 segments, this gives us
dTmax = 0.0063 [C]
about double the uniform heating case.
* I also considered that since the wire has significant stress due to the test mass weight, the Young's modulus's temperature dependence might cause a different effective thermal expansion coefficient alpha_effective. This appears to be a negligible effect.
From gwinc, the temperate dependence of the young's modulus E is
dE/dT = -2.5e-4 [1/C]
and young's modulus E is
E = 212e9 [Pa]
from https://alog.ligo-la.caltech.edu/aLOG/index.php?callRep=12581, we know that the change in spring length due to the modulus of eleasticity dependence is
dL = -dE/dT * dT * Tension / Stiffness
where Tension is the load in the wire and Stiffness is the vertical stiffness of the wire.
The Stiffness is given by
Stiffness = E * A / L = E * pi * r^2 / L
where A is the cross sectional area of the wire, and r is the radius.
So plugging this in above
dL = -dE/dT * dT * Tension * L / ( E * pi * r^2 )
We get the correction on alpha by dividing this by L and dT, which eliminates both from the equation. From the HLTS model, the bottom mass is 12.142 kg and the wire radius is 1.346e-4 m.
Tension = 12.142 * 9.81 / 4 = 29.8 [N]
The correction on alpha is then
-dE/dT * Tension / ( E * pi * r^2 ) = 2.5e-4 * 29.8 / (212e9 * pi * 1.346e-4^2) = 6.2e-7 [1/C]
This changes alpha from
12e-6 to 12.6e-6 [1/C]
Not enough to matter for the estimates above.
Localizing the heat source:
I made a calculation of the heat absorption by wires.
Based on Brett's temperature estimate, assuming the radiation as the only heat dissipation mechanism, the heat the front wires should be absorbing is about 1uW total per two wires when SR3 tilts by 1 urad regardless of the temperature distribution.
If you only look at the power, any ghost beam coming from PRC power (about 800W per 20W input assuming recycling gain of 40) can supply 1uW as each of these beams has O(10mW) or more.
I looked at BS AR reflection of X reflection, CP wedge AR both ways, and ITM AR both ways. I'm not sure about the first one, but the rest are mostly untouched by anything and falls on SR3 off centered.
The attachment depicts SR3 outline together with the position of CP wedge AR (green) and ITM AR (blue) reflections, assuming the perfect centering of the main beam and the SR3 baffle on SR3. Note that ITMX AR reflection of +X propagating beam falls roughly on the same position on SR3 as ITMY AR reflection of +Y propagating beam. Ditto for all ITM and CP AR reflections. The radius of these circles represent the beam radius. The power is simply 20W*G_rec(40)*(AR(X)+AR(Y))/4 (extra factor of 2 due to the fact that the AR beam goes through the BS) for ITM and CP, and 20W*40*AR/2 for BSAR of -X beam.
I haven't done any more calculations and I don't intend to, but just by looking at the numbers (total power in green and blue beams in the figure is about 240mW, 5 orders of magnitude larger than the heat absorbed by wires), and considering that the centering on SR3 cannot be perfect, and that SR3 baffle is somewhat larger than SR3 itself, and that CP alignment is somewhat arbitrary, it could be that these blobs seeps through the space between the baffle and the SR3 and provide 1uW.
The red thing is where BSAR reflection of -X beam would be if it is not clipped by the SR2 scraper baffle. If everything is as designed, SR2 scraper baffle will cut off 90% of the power (SR2 edge is 5mm outside of the center of the beam with 8mm radius), and remaining 10% comes back to the left edge of the red circle.
Any ghost beam originating from SRC power is (almost) exhonerated, because the wire (0.0106"=0.27mm diameter) is much smaller than any of the known beams such that it's difficult for these beams to dump 1uW on wires. For example the SRC power hitting SRM is about 600mW per 20W input, SRM AR reflection is already about 22uW.
Details of heat absorption:
When the temperature on a section of wire rises, the stretching of that section is proportional to the length of that section itself and the rise in temperature. Due to this, the total wire stretch is proportional to the temperature rise integrated over the wire length (which is equial to the mean temperature rise multiplied by the wire length) regardless of the temperature distribution as is shown in effect by Brett's calculation:
stretch prop int^L_0 t dL = mean(t) * L
where L is the length of the wire and t is the difference from the room temperature.
Likewise, the heat dissipation of a short wire section of the length dL at temperature T+t via radiation is
sigma*E*C*dL*[(T+t)^4-T^4] ~ 4*sigma*E*C*dL*T^3*t
where sigma is Stefan-Boltzmann constant, E the emmissivity, C the circumference of the wire, T the room temperature (about 300K). The heat dissipation for the entire length of wire is obtained by integrating this over the length, and the relevant integral is int^L_0 t dL, so again the heat dissipation via radiation is proportional to the temperature rise integrated over the wire length regardless of the temperature distribution:
P(radiation) ~ 4*sigma*E*T^3*(C*L)*mean(t).
I assume the emmissivity E of the steel wire surface to be O(0.1). These wires are drawn, couldn't find the emissivity but it's 0.07 for polished steel surface and 0.24 for rolled steel plate.
I used T=300K, t=3mK (Brett's calculation for both of the temperature distributions), C=pi*0.0106", L=0.255m*2 for two front wires, and obtained:
P(radiation) ~ 0.8uW ~ 1uW.
ITM AR:
ITM has a wedge of 0.08 deg, thick side down.
ITM AR reflection of the beam propagating toward ETM is deflected by 2*wedge in +Z direction. For the beam propagating toward BS, ITM AR reflects the beam, deflecting down, and this beam is reflected by ITM and comes back to BS. Deflection of this beam relative to the main bean is -(1+n)*wedge.
AR beam displacement at BS is +14mm for +Z-deflection and -17mm for -Z-deflection. Since the BS baffle hole "radius" seen from ITMs is 100+ mm, and since the beam radius is about 53mm, AR beams are not blocked much by BS baffle and reaches SR3.
ITM AR reflectivity is about 300ppm.
CP AR:
Similar calculation for CP except that they have horizontal wedge, thick part being -Y for CPX and -X for CPY.
CP wedge is about 0.07 degrees.
I only looked at the surface of CP that is opposite of the ITM, and assumed that the surface facing ITM is more or less parallel to ITM AR, within an accuracy of O(100urad).
I assumed that S1 is the surface close to the ITM, and took S2 AR numbers from galaxy web page (43.7ppm for X, 5ppm for Y).
BS AR propagation:
BS wedge is 0.076 degrees, with a reflectivity of 50ppm.
Deflection of BS AR reflection of -X beam relative to the main beam is NOT -2*wedge as BS is tilted by 45 degrees. With some calculation it turns out that it is about -0.27 degrees, with a displacement of +48mm (positive = +X).
This beam is not obstructed at all by the BS baffle, hits SR3 and makes it to SR2 baffle edge. What made it to the SR2 surface doesn't go to SRM and instead comes back to SR3 as SR2 is convex and the beam is heavily off-centered.
If there's no SR2 baffle and if SR2 is much larger, the center of the reflected beam is going to be 50cm in -X direction from the center of SRM, which happens to be on SR3.
I don't know what happens to the edge scattering and the reflection from SR2, but both of these are highly dependent on SR2 centering.
We've had three locklosses at 23 Watts in the last 4 hours. The first one of these did coincide with a gust of wind (plot attached), although it might not have been the cause. We've been able to stayed locked with gustier wind in the past at 10 Watts.
In all three of these locklosses there were fluctuations in the POP90 power on 10s of seconds timescales.