Manasa and I have been wondering why the low frequency seismic noise has been different in the last few days/weeks. I went over to visit the Rock Monster, a.k.a. the Earth Surface Dynamics Laboratory next door, and the grad student turned it up for me (increased water flow significantly) for a few minutes. Then I came back to look at the BLRMS, and you can see the low frequency increase a few minutes ago, when he turned it up on high. He said that they run it on low almost all the time, 9am-5pm ish, and on high for an hour or so at a time periodically during the day.
The air cond is out of order at the area covered by racks 1 X 1 through 1 X 7
The arm X and Y AC units are working.
Granite base 20" x 20" x 5" locations are on the CES side of our IFO arms: as shown ETMY_ south-west, ETMX_north-east, ITMX_south-east . No height limitation. This side of the tube has no traffic.
SS cover McMaster# 41815T4 (H) SS container cov
This is my interpretation of where Steve is proposing to place the seismometers (he wrote ITMX southwest, but I'm pretty sure from the photo he means southeast).
I think his point is that these locations are on the less-used side of the beam tube, so they will not be in the way. Also, they are not underneath the tube, so we will not have any problems putting the covers on/taking them off.
Outside air quality at 8:30am 1.1 million of 0.5 micron particles cf / min with MET counter #2
AC unit output measured directly at the outlet of east end 6,000 and south end 3,000 of 0.5 micron particles cf / min with counter #2
Lab measurement at the top of IOOC 20K of 0.5 micron particles cf / min with MET #1
HEPA filters: 2 mobile units at the middle of the east arm at speed 100%, PSL enclosure 20% and south end flow bench are running.
The PSL, south flow bench and mobile unit (Envirco sn69406003 ) measured zero counts of 0.5 & 0.3 micron particles
Envirco HEPA filter unit sn 69406001 measured 50 particles of 0.5micron and 320 of 0.3 micron particles cf / min with counter #2
This filter will be replaced.
NOTE: inside air quality peaks we can not control. It depends on the weather and our house keeping.
When your work is particle sensitive keep your eyes on the particle counter.
We got granite bases today from the manufacturer. We plan to set them up on Wednesday, 8 am. Please note, there will be an installation mess at Xend, Yend and corner during ~4 hours. Let us know if you have any objections to do this at this particular time.
Installation locations are specified in elog 8270, scheme attached is valid except for Xend. Instrument will be installed on the place of nitrogen containers.
( next to the wall at corner sout-east of the south end )
The carpenter shop finished the installation of the 3 granite bases.Rapid Set Cement All high strength non-shrink grout was used.
Compressive strength 3000 PSI at 1 hour and 9000 PSI at day 28 The janitor is still cleaning up after them at the south end.
The soft silicon gas kits are working well with the SS can. Den is making the adaptor plate drawing for the feedthrough.
I moved the two Trillium seismometers that Den left on the electronics bench out onto the new concrete blocks in the lab that will be their final resting places. I moved one onto the slab at the vertex and the other to the slab at the Y end. I left them both locked and just sitting on the concrete.
The pile of readout electronics that were sitting next to them I moved on to the yellow foam box half way down the MC tube, between the MC tube and the X arm tube. This is obviously not a good place to store them, but I couldn't think of a better place to put them for the moment.
To put everything in one place I add a final drawing of the base to this elog.
Next time we continue with wiring and putting temperature and pressure sensors inside the box. Connector support plate drawing is attached. We'll have sensors inside the kit with STS-2 or Trillium as their connector is small enough (19 pin vs 26 pin for Guralps) that we can put an additional 4 pin lemo connecor (2 pins for each sensor). I think EGG.0B.304.CLL is good for this application. Temperature and pressure sensor we can by from omega.
Something that I want to look at is the coherence between seismic motion and PRM motion. Since Den has been working on the fancy new seismometer installations, I got caught up for the day with getting the new corner seismometer station set up with a T240. Later, Rana pointed out that we already have a Guralp sitting underneath the POX table, and that will give us a good first look at the coherence. However, I'm still going to write down all the cable thoughts that I had today:
The cables that came with the electronics that we have (from Vladimir and tilt meter -land) are not long enough to go from the seismometer to 1X7, which is where I'd like to put the readout box (since the acquisition electronics are in that rack). I want to make a long cable that is 19pin MilSpec on one end, and 25pin Dsub on the other. This will eliminate the creative connector type changes that happen in the existing setup. However, before making the cable, I had to figure out what pins go to what. So.
25pin Dsub 19pin MilSpec
4 No conn
6 R and V
9 No connection
13 No conn
16 R and V
17 No conn
23 No conn
I am not sure why R and V are shorted to each other, but this connection is happening on the little PCB MilSpec->ribbon changer, right at the MilSpec side. I need to glance at the manual to see if these are both ground (or something similar), or if these pins should be separate. Also, I'm not sure why 19 and 20 are shorted together. I can't find (yet) where the short is happening. This is also something that I want to check before making the cable.
Den had one Female 19 pin MilSpec connector, meant for connecting to a T240, but the cable strain relief pieces of the connector have 'walked off'. I can't find them, and after a solid search of the control room, the electronics bench, and the place inside where all of Den's connectors were stored, I gave up and ordered 2 more. If we do find the missing bits for this connector, we can use it for the 2nd T240 setup, since we'll need 2 of these per seismometer. If anyone sees mysterious camo-green metal pieces that could go with a MilSpec connector, please let me know.
Evan brought the Guralp handheld readout paddle and cables back from the ATF (Zach is using GUR2 and one of the T240s for gyro stuff this week), and we recentered the GUR1 masses. N/S and Vert were okay (within 0.1 V), but E/W was at -0.5 V, so we set it at zero. We then plugged the Guralp back in, and turned on the readout box.
There isn't much of a change on the BLRMS on the wall, so it's possible that we weren't actually having any trouble anyway.
For quite a while (no one knows how long), we've seen fluctuations in the 10-30 Hz seismic motion. This shows up as the purple trace on the seismic BLRMS on the wall projector.
The second plot shows that this is not only a periodic increase in the usual 29.5 Hz HVAC peak, but also an anomolous 32.2 Hz peak. Probably some malfunctioning machinery - maybe in the 40m or maybe on the roof.
The BLRMS are totally crazy today! I'm not sure what the story is, since it's been this way all day (so it's not an earthquake, because things eventually settle down after EQs). It doesn't seem like anything is up with the seismometer, since the regular raw seismic time series and spectrum don't look particularly different from normal. I'm not sure what's going on, but it's only in the mid-frequency BLRMS (30mHz to 1Hz).
Here are some 2 day plots:
Particle counts were measured inside the PSL enclosure at 40VAC variac setting.
Directly under HEPAs, on the east half of the optical table : 0.3 micron 20 particles / cu ft, 0.5 micron 0 p / cu ft, 0.7 micron 0 p / cu /ft
Away from the HEPAs, on the west edge of the op table: 0.3 micron 960 particles / cu ft, 0.5 micron 50 p / cu ft, 0.7 micron 20 p / cu ft
We may want to increase the RPM a little bit.
Checked our counters against recently calibrated Met One GT-526:
#1 is right on, #2 measured 25% less (it will go for calibration)
Flow bench at the south end : zero particle for all 3 sizes
IOO chamber particle logging measures 0.5 and 1 micron. Chamber opening limit is set to 10,000 particles max of 0.5 micron
At 10,000 p of 0.5 micron means ~100,000 - 180,000 p of 0.3 micron
We may have to lower the limit.
Its an increase in the microseismic peak. Don't know what its due to though.
Keven and Steve,
The 3 cranes tested and wiped off as preparation for upcoming vent.
Once you install a matlab newer than 2012a, you can install ligoDV as a matlab app and get the NDS2 client software for free. So you can easily get the 40m data from the outside world now and do the analysis on your own computer rather than login through nodus.
1)Power to the seismometers were turned down,
2)Guralp2 was moved to North side of POX table
3)Guralp2 was aligned in N-s Direction and leveled before connecting
4)Power to seismometers was turned on once Guralp2 was connected
An exercise of optimally subtracting one seismometer signal by another using weiner filters was done. Results have been summarized document attached.
I used MC_L signal from the Mode Cleaner as the desired signal with GUR2_X as witness signals. I observed good subtraction where coherence is high. But there was noise added in other frequency bands. I am not sure how to avoid that.
Please find attached documents that contains relevant plots.
Our fluorecent lights became obsolete. We'll have change fixtures over to some more energy efficient one. Do you have any recommendation regarding to less noise performer unit?
We may go this direction of LED fluorecent lamps ?
~Vancuver, Canada earthquakes: magnitude 6, 5 and more shaking
Local m3.8 eq shakes PRM lose.
After seeing all of these spikes in the BLRMS at high frequency for awhile, I power cycled the Guralp interface box (@ 10:21 PM) to see if it would randomly recenter in a different place and stop glitching.
It did - needs to be better centered (using the paddle). Plot shows how the Z channel gets better after power cycle.
How can we improve the cleanliness of the 40m IFO room 104 ? May be Mario Batali crocs if you chief chef of the lab likes it. We can do more effective things.
Atm 1 is showing the lab air quality dependence on outside air measured at the top of the IOO chamber. This made me to measure the differential pressure between lab and out side.
Properly sized air conditioner is over pressurizing it's room by 0.05 [" Water] like clean assembly room.
The 40m at Vertex location is barely getting pressurized to 0.01 " W
The control room is OK with 0.04 " W but it's air quality is very bad! It is 10x worse at 0.5 micron than IFO room.
Every entry from well pressurized control room into barely pressurized IFO pumps dirty air to our "clean room."
This door should be closed.
The drill- room entry is ideal because it is using the same air conditioner as the main lab, therefore it has cleaner air.
Things to do: seal holes of CES walls, seal paint wall at south end so it will shed less, replace gas kits on doors.
I have plugged the cable tray space entering the control room above Rosalba.
Probably more important is to establish quantitatively how particle counts affects the lock acquisition or noise in the interferometer.
We don't want to adopt a "Sky is Falling" mentality as was done previously in LIGO when people were trying to outlaw burritos and perfume.
Dust monitor counts and human noses do not correlate well with the interferometer's nose.
When the vacuum system is closed, we might check to see if particle counts correlate with losses in the PMC or excess scatter on the ISC tables. If not, we should move on to other concerns.
This was the second week without wet mopping the floor and wet wipe down of the vacuum envelope.
We changed filters on the 40m "HEPA" vacuum pump. It still has very dirty exhaust. Do not use it in clean room!
[Alan, Koji, Manasa]
Record number of 50 freshmen were given tour of the 40m this afternoon.
Sunday evening fireworks. Manasa heard it.
The 4th week of no wet mopping of the floor and no wet wiping the vacuum envelope.
We cleaned the intakes of the south arm IFO air condition. The bottom duct have quite a bit accumulation Atm1
See wet wiped contrast on Atm2
We found 3 holes around pipes ( coming from CES ) on the east wall that has to be sealed.
After closer examination of these holes, they are sealed off well.
As you may recall, Den designed some nice seismometer stations for us with the help of Steve. The granite base was installed : elog 8461. The point of these is to have nice solid bases for our seismometers to sit on, rather than the flimsy linoleum flooring. Also, they are covered (and will be insulated) to help prevent air currents and temperature fluctuations from affecting our seismometer measurements. Even though these seismometer stations have been in place for a few months, we are not yet taking advantage of them. This is a status elog, so that we know what needs to be done.
Recently, Den finished up the design for, and Steve ordered, and we received, the small aluminum plates that go on the side of the granite slabs, so that we can feed the connectors for the seismometer through the baseplate, in an airtight way.
The current plan is to use one Guralp at each end station, and the Trillium at the vertex. As of this moment, we have 1 Guralp at ETMY, 1 Guralp at ITMX, and a Streckeisen at ETMX, and the Trillium is sitting to the south of the POX table.
Most of the work that's left to do is just to place the seismometers on the new stations, and to make cables.
I have taken an inventory of all the things that I think we need to buy (or I need to find in the lab) in order for us to finish this project up.
We need to buy a LEMO connector for the T-240 plate.
We need to buy 6 O-rings: 3 to go between each aluminum plate and the granite slabs, the other 3 between the plate and the milspec connectors for the seismometer cables.
We need to buy or confirm that we have screws to attach the plates to the granite slabs.
We need to buy or confirm that we have screws to attach the milspec connectors to the plates.
I need to confirm that I have another 37-pin dsub for the Xarm Guralp cable, and a 25-pin dsub for the Trillium.
Assuming that I am reusing the existing Yarm Guralp cable, we have all the milspec connectors necessary.
I have a 30m long spool of 19-pair cable that I will use to make the Trillium cable. I have a long cable, formerly a Streckeisen cable, that I will cut the ends off of, and make into a Guralp cable. (We had 3 of these incredibly long, maybe ~50m cables - one became the Yarm Guralp cable, one is waiting to be the new Xarm Guralp cable, and the 3rd one is connected to the Streckeisen that we still have).
Work to be done:
* Make long cables for Xarm Guralp and Vertex Trillium. Check pinouts for the milspec -> dsub connections on each cable.
* Make small cables that go inside of the granite and seismometer station. These are to connect the sensor to the aluminum plate, and then the long cables go from the plate to the readout box. Unfortunately, the holes in the granite are not large enough to pass a connector through, so these will have to be soldered in-situ.
* Plug in the Trillium readout box and confirm that it's working / makes sense.
Longer term modifications and add-ons:
* Lemo connector with wiring for temperature and pressure sensors inside the vertex station. I believe that Den was looking into what sensors we might want.
* Needle valve for slow pressure equalization on vertex station (all stations should have this, but only the Trillium plate has a hole for this).
Is there anything else that I'm forgetting?? Please reply with thoughts.
I attach the drawings for Guralp and T-240/STS-2 connector plates. Drawings contain all information about the screws, O-rings and connectors.
Basically, box mounting receptacle for seismometer cable is attached to the connector plate with 6-32 screws. Inside cable should be ~ 1m long and connect the plate with seismometer.
For T-240 realization we have an additional LEMO connector for temperature and pressure monitoring inside the station. We should buy sensors and plug them into some machine with slow controls.
LEMO connector has 9 pins. 4 will be used for temperature and pressure sensors and spare 5 can be used for future ideas.
Also I think it might be better to put two T-240 into isolation stations.
It would be nice if we could use the existing seismometer cable and place a 2-terminal temperature sensor within the stainless-steel can. A device like the AD590/592 can drive current over a long cable run without pickup issues since its a current source. Inside of the seismometer breakout box we should make a circuit to scale the signal to be close to zero at 25 C and have a slope of 1 V/deg. There are example circuits in the application note - we can just make them on a piece of vector board and glue to the inside of the breakout box (where we connect to the regulated power).
This is not a test. Life can be dangerous in the 40m Control Room.
It looks like there was a 4.4 magnitude earthquake near Fontana, CA around 1:30am today. This tripped all of the suspension watchdogs, which Q has just now re-enabled.
Earth quake shake down yesterday Atm1
Atm2, today's shake
Please wet WIPE before opening chamber or optical table ! !
with methanol soaked kimwipes.
The Met One particle counter is located on CES wall, just behind ITMX chamber.
The numbers are not so bad, but have you ( ...a) asked the IFO lately?
The floor was cleaned under the east arm tube with hand held wet towel. We moved staff around and mopped. I did at the bottom of rack 1Y1, 2 and 3.
Last week we did the south arm tube floor.
Next week we 'd like to clean under rack 1X1,2,3, 4, 5, 6 and 7
1Y4, 1X1,2,3,4 & 5 instrument racks floor space were cleaned.
Last night we noticed an excess in the GUR1Z seis BLRMS on the StripTool. It was in the 0.1 - 0.3 Hz band. The rumor in the control room was that "this kind of noise has been showing up at night recently".
AS it turns out, this was not some environmental noise around the 40m at night, but instead its some internal servo oscillation in the GUR1 Z channel. In the Guralp seismometers, each channel is a different mechanical sensor (unlike the STS or T240), so when a single channel gets noisy it doesn't always implicate the others.
My guess is that the oscillation came from the Z channel needing to be recentered. I power cycled the interface box just now. The oscillation had already gone away, but I thought this might reduce the excess noise. Maybe it did, but the effect is tiny. You can see in the oscillation reference that the low frequency noise is high, but in the new trace its still kind of high. Needs to be re-centered correctly with the paddle. Or add a centering button to the interface box.
1X6, 1X7 and 1X9 instrument racks floor space were cleaned today
Please take a look at the table top with the flashlight before removing it. If it is dusty, wipe it down with dry lint free cloth in the box.
There is one box with flash light and wiper at AP, ETMY & ETMX optical tables.
Koji locked the MC, arms, and PRMI, with no troubles, after the M8.2 earthquake off the coast of Chile, that happened about 4 hours ago.
Atm2, Chilean 8.2M eq arrived to the 40m 16:57 in 10 minutes. Our OSEMs did not see them. Hanford got it 2 minutes later.