Jenne, Diego, Kate
We want to conduct a huddle test with the three 40m seismometers (2 Guralps and 1 Trillium), so we began to get that set up in order. All three are currently sitting on the large granite slab approximately halfway down the length of the MC tube. We had to move all three seismometers: the Trillium had been next to the BS and the Guralps at the end stations. All three are balanced and aligned and we have put the foam box over them.
The Trillium has not yet been used here, so we had to first wire its power supply. We're now providing its readout box with +/- 20 V. Getting that hooked up required powering down several electronics racks, which involved auxiliary prep work like turning off the suspension watchdogs. We also installed 3 new BNC cables to carry the Trillium x,y,z signals from its box to the CDS AA board. We're using the inputs which had previously been used for recording the STS2 signals.
We could find only one of the two 'short' Guralp cables, so at the moment just one of the two Guralps is powered and connected to CDS. Jenne made (some time ago) new cables so that we could leave the long cables that run from the corner to each end station in place to preserve the nominal setup.
Attachment/edit by Jenne: Seismic spectra. Note that the T240 is connected to the channels that are called STS_1. I compared the Guralp spectra to our seismic_ref, and they match up pretty well. The new spectra is maybe a factor of 2 or so above the reference, at a few Hz. Anyhow, the Guralp seems fine. I am sure that somewhere we have a second short (as in, not 50m long) Guralp cable, I just can't remember right now where it might be. Also, the T-240 has some seriously crazy noise up around 30Hz. What's up with that?? I want to ask Zach if he saw this when he had the Trillium, or if it is new.
In order to do high quality huddle subtraction, we need to align the seismometer axes to high precision. We would need 1000x subtraction to see the instrument noise floor, but are likely to only get 100x. For that we need to align the axes to 0.5 deg (or do a Wiener coordinate transform with the data). To do this, we need to use a high quality bubble level and eventually iterate after trying out.
We should strain relieve the seismometer cables on the slab. It should be a tight clamp so that acoustic vibrations on the cables are terminated at the clamp and don't get to the seismometers. The clamp can be attached to the slab using some strong epoxy.
AC maintenance is scheduled from 8am till 11am tomorrow morning.
IFO air condition maintenance will continue tomorrow morning and it should be finished by 11:30AM
We have new guys taking over this job: Sal and Chris so it takes longer. The units will be shut down for a bit.
They will not enter the IFO lab. The CES housed units will be worked on.
The first real rain of this year finds only one leak at the 40m
Yesterday morning was dusty. I wonder why?
The PRM sus damping was restored this morning.
I have just put the seismometers back into their nominal positions, on the concreted slabs. The T-240 is in the vertex, and the 2 Guralps are at the end stations.
The vertex location doesn't have a spaghetti pot right now. There is an aluminum support for cable trays that is welded to the supports under the beam tube that is in the way. The pot looks like it will fit barely, if it were slid totally horizontally into place. However we can't do that with the seismometer in place. I'll chat with Steve this afternoon about our options.
Since I don't know that we are planning on ever putting a cable tray on the inside of the beamtube, perhaps we can cut ~6 inches of this piece away.
Aluminum support beam removed and seismometer is covered.
I opened up the spaghetti pot over the vertex seismometer, and taped the cable to the slab. The way the cable is coiled, it was touching the underside of the seismometer. Now the only connection is at the cable connector. There is a ~few inch bit of cable, then it's taped down.
Yesterday afternoon at 4 the dust count peaked 70,000 counts
Manasa's alergy was bad at the X-end yesterday. What is going on?
There was no wind and CES neighbors did not do anything.
It's super cold in the control room and EE bench area tonight. I'm wondering if, similar to what happened on Dec 29th (http://nodus.ligo.caltech.edu:8080/40m/10846) the campus steam is off? Or just our heater is broken? The thermostat is cranked up to 80 over by the bathrooms (this is usually ~74F), but we're still cold.
It's 69F in the control room right now (usually mid-high 70s).
EDIT, JCD, 4am: It's 64.3F in the desk area, 67.8F in the control room. It also smells in the control room like some heater has been off for a while, and is turning back on - that burned dust smell that happens after you haven't turned on the heater all summer.
EDIT again: The burn-y smell is getting stronger I think. Security is sending someone over to come check it out.
After some searching, including help from 4 security guys (I think they don't have a lot to do at 4:30am :), we found that Ottavia is super warm, and smelled burn-y. She has been powered down and unplugged. Security guys may call Steve's desk to follow up later today.
The 40m fenced area will start storing this large ~ 8000 lbs chamber on April 14. The asphalt will be cut, jack hammered the next 2-3 days in order to lay concrete.
Their schedule is from 8 to 5 starting tomorrow. We are asking them to work from 6 to 3pm
ETMX is about 12-15 ft away
The 40m fenced area will start storing this large chamber on April 14. The asphalt will be cut, jack hammered the next 2-3 days in order to lay concrete.
Jackhammering was happening around 7:30am
It looks like it did no harm. It is too early to say what may have moved. Rana's worrisome email was late.
The ground preparation is completed.
Unfortunately, this kind of trend plot is not detailed enough to know if something has gone bad in a quantitative way. But at least we can tell that the suspension wire didn't break.
Q is writing the locking elog for the night, but just to reply to this thread: The IFO worked well tonight, so things are at least not broken.
There was a period of short unexpected jackhammering this morning. I asked them to stop.
The good mood of GTRX was not changed.
It is here.
Air cond filters checked by Chris. The 400 days plot show 3 bad peaks at 1-20, 2-5 & 2-19
Looks like some of our seismometers are oscillating, not mounted well, or something like that. No reason for them to be so different.
Which Guralp is where? And where are our accelerometers mounted?
Reward being offered for the safe return of this thing:
COD_Sugar napolion is due to Steve: Item delivered, model CMG-SCU-0013, sn G9536
Today Steve and I tried to recenter the Guralps. The breakout box technique didn't work for us, so we just turned the leveling screws until we got the mass position outputs within +/-50 mV for all DoF as read out by the breakout box.
The attachment shows the 6 channels after our work. You can see that GUR2_X/Y still look deadish. I tried wiggling the cables at the interface box and powering on/off, but no luck. Next, we swap cables.
Tried to bring the weather station back to life, but no luck. The unit on the wall is alive and so is the EPICS IOC (c1pem1). But there is apparently no communication between them. telnet into c1pem and the error message repeating at the prompt is:
Weather Monitor Output: NO COMM
Might be related to the flaky connector situation that Liz and I found there a couple summers ago, but I tried jiggling and reseating that one with no luck. Looks like it stopped working around 8 PM on March 24, 2014. That's the same time as a ~30s power outage, so perhaps we just need some more power cycling? Tried hitting the reset button on the VME card for c1pem1, but didn't change anything.
Let's try power cycling that crate (which has c1pem1, c0daqawg, and some GPS receiver)...nope - no luck.
Also tried power cycling the weather box which is near the BS chamber on the wall. This didn't change the error message at the c1pem1 telnet prompt.
Tried swapping cables at the Guralp interface box side. It seems that all of our seismic signal problems have to do with the GUR2 cable being flaky (not surprising since it looks like it was patched with Orange Electrical tape!! rather than proper mechanical strain relief).
After swapping the cables today, the GUR2 DAQ channels all look fine: i.e. GUR1 (the one at the Y end) is fine, as is its cable and the GUR2 analog channels inside the interface box.
OTOH, the GUR1 DAQ channels (which have GUR2 (EX) connected into it) are too small by a factor of ~1000. Seems like that end of the cable will need to be remade. Luckily Jenne is still around this week and can point us to the pinout / instructions. Looks like there could be some shorting inside the backshell, so I've left it disconnected rather than risk damaging the seismometer. We should get a GUR1 style backshell to remake this cable. It might also be possible that the end at the seismometer is bad - Steve was supposed to swap the screws on the granite-aluminum plate on Thursday; I'll double check.
There was an earthquake: M4.0 - 40km SSW of South Dos Palos, California
No noticeable effects on the IFO. MC did not lose lock; however the arms did unlock.
I was wondering about the design of the BLRMS fitlers for the seismic channels since the STS ones seem to have so little gain compared to the Guralps.
Here are some plots of the Bode magnitude and impulse responses of the bandpass filters (before the low passing). There's a bunch of entries from Masha on this from her SURF summer. Can anyone comment on why they are all so different?
One of the old Masha entries speaks of designing the lowpass filter in an intelligent way: by adjusting the filter order until the power in the stopband is less than 1% of the power in the passband. Seems like we could do that for bandpass too. For now I have made the names reasonable and changed all of the BP filters to 4th order Butterworth.
Also, it turns out that the Vel2Vel (gain ~0.02) filters were mistakenly on in the STS BP filter banks. The GUR inputs have a gain to scale the counts to velocity, but the STS seem to already be in microns/sec (where is this gain?) so I turned off and deleted the Vel2Vel filters; in any case the gain should not be done seperately in each BP bank, but altogether before the BP filtering.
The cable tray holder cross beam is removed and cut short for good access to seismometer.
The Guralps were swapped.
What I did: turned DC power off at 1X1, hand carried them, centered each leveling bubbles, gently locked the jack screws and turned power back on.
ETMY at the east end now has CMG-T40-0008, sn T4157 as channel C1:PEM-SEIS_STS_1_Y_OUT_DQ.........
ETMX at south end now has CMG-T40-0053, sn T4Q17 as channel C1:PEM-SEIS_STS_2_Y_OUT_DQ.........
Conclusion: Guralps are fine. X cable is bad. It was bad 6 months ago when it was made.
We can still swap the 3ft short cables at the granite base if Rana has not done it.
You are plotting the STS channels, not Guralp. These are for the Trillium 240 seismometer.
Also, you cannot tell if the seismometer is working by plotting the MEAN trend. That just gives the average and we need the fluctuations. Better off looking at the spectrum like I did last time.
And....its not good enough to just do the bubble. You have to do the mass centering procedure that you and I did last time with the breakout paddle.
Koji and Steve,
The result: bad Guralp x-arm cable.
I will swap the short cables tomorrow at the base.
Short 46" long cables at the base plates were swapped. Their solderings looked horrible.
This cable actually worked at 5-5-2015
Bad cable at ETMY station now. The new cable should be a little bit longer ~52"
I've set up the Wilcoxon accelerometers on the SP table for a huddle test, to estimate their noise levels.
They're clamped down to the table along the same axis, and their housings are in good contact, in hopes to make them as correlated as possible.
Steve helped me move the DAQ cables from under the BS/PRM oplev table, to dropping from the cable tray above the POX table, so I could get them plugged in at the SP table. This also helps reduce the rats nest by the access connector, and is a fine location for when the accelerometers are attached at MC1 & MC2.
A quick glance at DTT shows coherence of >0.9 from about 2-100Hz for all six. A three-corner-hat deal will provide an easy estimate of the noise floor of each one. If we feel like being fancy / accounting for possible gain differences, we could try some MISO wiener action, but that is probably overkill.
Here are some results for the 3-corner hat subtraction for the six accelerometers, from ~1 hour of data that didn't look to have any sharp features/glitches from human activity in the lab.
I used the python uncertainties package to try and get an estimate of the uncertainty in the subtracted noise floor, by taking into account every possible possible combination of 3 sensors and the fluctuations in the spectrograms of the subtracted signals. I've attached the python code if anyone is interested in the implementation.
I pulled out the accelerometer data sheets to read their slightly varying V/g calibration (which differs on the order of a few percent from unit to unit). This improved the subtraction factor from ~20 to over 100 at some frequencies. I've edited the filter modules such that the OUT_DQ channels are already calibrated into m/s^2.
The accelerometers have been installed at MC1 and MC2. MC2 data is live, I haven't yet run the cables from the MC1 set to the preamp yet, though.
MC1 accelerometer has been plugged in. The modecleaner locking has been intermittent today, but I looked at a 15 minute lock in DTT, looking at the STS1 seismometer and both accelerometer triplets. Plot and DTT xml attached.
For the sake of not cluttering up everything with legends, the coherence plots are organized by direction (x, y, z), and include the coherence of each of the three sensors (sts, acc1, acc2) with the IMC control signal and the IMC transmitted RIN.
To improve our sensor noise estimate, the ACC cables should be clamped using a rubber pad and a big dog clamp on the SP tabletop before exiting the table. Also the sensors themselves should be covered with a foam box or a double cardboard box. The high-frequency acoustic noise may limit the 10 Hz performance since piezos are not very linear.
I've set up the Wilcoxen accelerometers on the SP table for a huddle test, to estimate their noise levels.
Wilcoxon. Not Wilconox or Wilco or Wilcoxen. Have some pity on future keyword searchers.
Keven is our regular janitor is out for a few weeks.
The sub is careful- gentel Mario. We wiped arouind the vertex cambers north side on the floor and east arm racks.
Mario wiped the floor around the ETMX chamber today.
Updated: On Thursday/Friday (sorry for late elog) I was messing with Eric's Wilcoxon 731A accelerometer huddle test data that was taken without the box and cables being adjusted properly. Anyways, I performed the three cornered hat analysis as he had done but I also performed a six cornered hat method as well instead of permuting around in pairs of three accelerometers. The following plots of the ASD's show the results,
It is interesting to note the improvement at low frequencies when six accelerometers are used instead of six while at higher frequencies we can clearly see how the results are worst than the three hat results.
I decided to take a mean of all six accelerometers measured ground signal as well as that for their computed selfnoises, this is plotted below,
Notice the obvious improvement along the entire frequency band of the measurements when all accelerometers are used in the data analysis.
I also performed some Wiener filtering of this data. There was an obvious improvement in the results,
The mean of the signals is also plotted below, just as I did with the cornered hat methods,
I also compared the mean self noise of the accelerometers against the manufacturers calculated selfnoise that Rana put up on Github. Both methods are compared against what the manufacturer claims,
As expected the measured noise curves of the Wilcoxon is not as good as what the manufactures stated. This should improve once we redo the huddle test with a better experimental setup. We have some pretty interesting results with the six cornered hat method at around 5 Hz, it is surprisingly accurate given how rough the calculations seemed to be.
I have attached my code for reference: code_accel.zipselfnoise_allsix.png
SEE attachments for better plots of the six accelerometers...
Pasadena got 0.2" of rain on Saturday. Temperatures were high with high humidity since than.The ants were back in the Control room east side benches.
We have started using TERRO Liquid Ant Baits in January 2015 This worked very well to this point.
Tree new packages were opened yesterday and the ants are gone.
We can conclude that these baits must be replaced after 6 mounts.
The liquid baits contains BORAX and it is safe.
I have moved the MC1 accelerators and cable to the huddle test set up, in order to see how a six witness huddle test with the improved set up will do.
Here is a picture of the accelerometer set up,
Our motivation for doing this is to see if more witness signals used in the Wiener filter really does indeed improve subtraction, as it was seen from previous huddle results, specially in the region above 10 Hz.
We are done taking accelerator huddle test data. So I moved back all six accelerometers and cables to MC1 and MC2. I also relabel each of the accelerometers properly since the labels on them were confusing.
Koji soldered new 50" long cable for the Y station.
Please check the spectra. If something is wrong, please swap the cables between X and Y in order to see if the cable is still the issue. I believe the cable was nicely made as I carefully checked the connection twice or more during and after the soldering work.
Atm1, New short-50" long cable was installed at ETMY end ( Y-station ) between Guralp-B ( MIT ) and granite base.
Interface box input 2 was left connected to cable 1 and input 1 to cable 2. This plot shows no change.
Atm2, Than I swapped the two long cables at the interface box
Now the signal seems to be ok <2 Hz,
>2 Hz some problem exist.
50" short cable
I will look for more bad soldering tomorrow. How many cables did she make?
We have to redo this cable also
The wasp nest will be removed tomorrow from from the out side of the east arm window.
The resonant frequency of the newly arrived gravity bee detector is not known.
The wasp terminator came in today. He obliterated the known wasp nest.
We discovered a second wasp nest, right next to the previous one...
Jessica wasn't too happy the wasps weren't gone!