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.

QED

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.

I will look for more bad soldering tomorrow. How many cables did she make?

We have to redo this cable also

OMG

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!

​

In previous elogs, we saw that the X and Y spectra out of GUR2 (X end Guralp seismometer) looked strange (i.e. inconsistent with the GUR1 spectra). 

This morning, Steve and I brought the handheld control unit to the Guralp to center the test mass, by adjusting the centering potentiometers inside the unit while monitoring the voltage readout corresponding to the DC mass position (manual has instructions). 

At first glance, this seemed like the likely culprit, as the offsets for the horizontal directions were much larger than the vertical one. We zeroed all three to within a mV or two. Unfortuntately, the spectra look the same as they did 10 hours ago. 

Since we already had the kit out, we checked the offsets for GUR1. Only the "East/West" had an offset over 50mV, so we zeroed that one, but left the others alone. 

Atm1, Before cable swap

Atm2, The long cables were swapped at the input of the interface box.

We can conclude that the problem is in the interface box

I wonder if interface box input 3 is wired?

Let's dismantle the I/F unit from the rack and connect the cable with the lid open.
We need to trace the signal.
 

IIRC, the Guralp box's 3rd set of channels do not have all of the modifications that were made on channels 1 and 2.

We found the same wasp in the 40m. Megan found it walking behind Steve desk!

The Guralp ADC  interface box  D060506 is ready for inspection. It is in front of 1X1 with open top and running.

Obviously c7 as 1 miroF cap is missing.

Koji and Steve,

We took transferfunctions of each channel yesterday. They were identical ?. I will check the cables from ADC to DAQ next.

As reported previously, the transfer functions of the channels look fine. (i.e. All channels almost identical.)
I checked the chain from the unit input to the DAQ BNC connectors. They were all OK.

Today I have been checking the signals on the unit with the long DB37 cables connected.
I could not see anything on the Gur2 channels on the board. I looked at the DB37 for Gur2 and felt something is wrong.

I opened the housing of the cable and realized that all the pins are not fully inserted.
The wires were crimped improperly and prevents them to be fully inserted.

=> We need to redo the crimping to insert them.
=> We need to check the other side too.

I'm making a new long cable. Both connector ends of this X arm long cable were terrible. It was removed from the cable tray yesterday.

The Y arm Guralp is running fine. The interface box is open in front of 1X1 on a cart and it is alive!    Please be aware of it !

Steve ordered about two weeks ago a roll of 0.5 mm thick copper foil to be used for the inside of the seismometer cans. The foil was then waterjet cut by someone in Burbank to the right dimensions (in two pieces, a side and a bottom for each of the three cans).

Today, we glued the copper foil (sides only) inside the three seismometer cans. We used HYSOL EE4215/HD3561(Data Sheet) as our glue. It is a "high impact, low viscocity, room temperature cure casting" that offers "improved thermal conductivity and increased resistance to heat and thermal shock." According to Steve, this is used in electronic boards to glue components when you want it to be thermal conductive.

We are going to finish this off tomorrow by gluing the bottom foil to the cans. The step after this involves soldering the side to the bottow and where the side connects. We have realized that the thermal conductivity of the solder that we are using is only ~50. This is 8 times smaller than that of copper and wil probably limit how good a temperature gradient we will have.

Some action shots,

Ara! Onara suru tsu-mori datta keh-do, un-chi ga de-chatta...

The new cable was made this way:

Pins were located with ohm meter for locations and both ends were cut off.The Belden 1424A cable than was soldered to DB37 and Guralp circular connector " IKPT06F16-26S-ND "

This cable will connect the ADC interface box CCD# DO 60506 to Guralp seismometer at the sout end.

The Guralp's each 3 axies will be connected through a twisted pair to the differential input op amp

Gur  ouput  vertical axis + -  on circular connector   A, B  to DB37 pin 1 &20

Gur output        N/S axis + -  on circular connector   C, D to DB37 pin 2 & 21

Gur output       E/W axis + -  on circular connector   E, F to DB37 pin 3 & 22

Power +12 VDC  from DB37 pin 29 to Gur circular connector pin c (lower case)

Power -12 VDC  from DB37 pin 24 to Gur circular connector pin  M Note: this connection was absent at the first test of this cable!

Ground              from DB37 pin 10 to Gur circular connector pin b (lower case)

Summery: I may destored the opamp  at the Guralp A at the south end.

To help find out if Steve really melted the inside of our precious seismometer, lets hook it up using the handheld seismo wand and see if it produces volts when we shake the ground.

Also, please stop using names like GurA or Gur1 or GurSuzy. We have GurX and GurY because they are at those ends. Anything else is confusing.

I moved Gur A from ETMX to ETMY . Gur B at ETMY was disconnected and its cable  connected to Gur A

It seems that Gur A is alive. I will stop using A and B names after we stop swapping components.

As it turned out, the "STS" BLRMS filters were all a mess, so I fixed them up today:

• BP and LP filters were non-existent for the 2 low frequency bands: 0.01-0.03 & 0.03-0.1 Hz. The 0.01-0.03 is just seeing tilt noise (its big in X & Y, but not in Z), but the other band is able to cleanly see the primary microseism at 0.06 Hz.
• There was some mixup and some BP filter banks had low pass filters while one of the LP banks had a BP filter.
• There were different filters between the X, Y & Z directions.
• The low pass filters had enough ringing in the impulse response that their outputs could sometimes go negative and make the SQRT block output NaN.

After tuning:

• All bandpass filters are 4th order Butterworth bandpass with the corners at the band edges (e.g. 1- 3  Hz)
• All low pass are the same, just scaled by the frequency band. They have a pair of real poles and a pair of 35 deg poles. The pole frequencies are set so that there is 40 dB of attenuation at twice the frequency of the low end of the bandpass. i.e. for the 1-3 Hz band, the low pass has > 40 dB atten at 2 Hz.
• The 3-10 and 10-30 Hz bands use the same low pass as the 1-3 Hz band, since I don't want to see aliasing in the EPICS readouts. I don't think we need faster than 1 Hz readback of the RMS.
• Confirmed with FOTON that the impulse response for the LP filters are positive for all t >0.

The "C1:PEM-SEIS_STS_1" filter banks are currently empty, so the signal is just in ADC counts. However, by amazing luck, this seems to be the right gain (within a factor of 2) to put the signal into units of microns / second. According the the schematic (D1000749), the default gain of 110 can be switched to make the whole box just have a gain of 2 (differential in, differential out). I wonder if anyone, like Jenne, knows if this is what we have? There's no elog I found about setting the gain switch.

According to the manual, the gain is ~1175 V/(m/s). Our ADC gain should be (2^16)/(40). So:

cal_gain = 1175 * 2 * 65536 / 40  ==>> 0.26 (m/s)/counts

I have put this into the STS_1_X,Y,Z filter modules in c1pem so that these channels are now calibrated. I also put the first few s-domain poles/zeros into the filter based on the manual so that the magnitude in the 10-30 Hz band is correct-ish now.

* Does anyone know how to center the masses on this thing?

Our online subtraction filters for PRC angle and MC length were trained on the raw ADC signals, so I've inverted the filters that Rana installed in the PEM filter banks in the OAF signal conditioning filter banks (C1:OAF-WIT_STS1X, etc.)

It's not perfect, since the inversion would be unstable, and thus needs a low pass. I used an ELP at 800Hz. The error in the inversion is then something like half a degree at 5Hz, which is the highest frequency we really ever subtract at. It should be ok.

No damage. The BS sensor UR 0.220 V has been low for some times.

Dataviewer does not work for long term trend.

ETMY - Guralp (B-MIT) was covered with copper lined can yesterday afternoon. It's long cable is connected to ADC interface box input 1

The vertex Trillium was covered just ~2 days before Ignacio left.

ETMX - Guralp (A-Caltech) is not covered. The long 40m cable is disconnected at the the south end.

Cable numbered #53 from Accelerometer 4 to 1X7 / DAQ input c26 was squased while removing network card from Sun Fire x4600 today.

This cable has to be tested.

ETMX was not much effected by this 8.3 M Chilian earthquake. It was kicked up and it was kicking for hours after it. This is a sign of instability but it maintaind it's position.

The 24 hours plot follows the tempeerature.

Building:         San Pasqual walkway East to West

                  (Between Holliston & Wilson)         

Date:             Thursday 11-12-15 to Wednesday 11-18-15

Time:             Between 6:00 a.m. and 4:00 p.m. each day        

Notification:     Possible Noise Vibration

Contact:          Ken Lewis (626) 298-2037       

* Plumbing contractor will be inspecting and water jetting Storm drains

Type of interruption: (Some vehicle noise and small vibrations limited to close surrounding area)

Areas effected: San Pasqual walkway from Holliston Street to Wilson)

Potential effects: storm drain loss of use

Reason for interruption: Storm drain cleaning in preparation for rainy season

Two mechanical and two sticdky traps were set to catch univited visitor.

Absolutely no food or food remains into inside garbage cans!!!!!!!!!!!!!!!!!!!!!!!!!

Our janitor confirmed that Q was not hallucinating about this animal. The dropping size indicating a good size one in the IFO room.

One of the mechanical traps moved from the control room to the east arm, close to the " machine shop " door.

I'm going to get more traps.

IFO restored after 4.5 Mag Banning, Ca earthquake.

Air condition maintenance is happening. It should be done by 10am

The noisy fan belt on the roof of the control room was finally replaced on Friday, Jan 22 2016

Objective:  measure the noise floor on the optical table and the floor so we can decide if the table needs better anchoring before swapping in

                   the larger optical table

The accelerometrs labeled as MC1 ( just north east  of IOO chamber floor ) and MC2 ( north east leg of MC2 table floor ) were moved:

MC1 to the floor at the north west leg of optical table.

MC2 is in the north east corner of the optical table

Atm2 was taken after table leg bolts were tighed at 40 ft/lb

The spectrum looks similar to ETMY     (Guralp for below 3 Hz )  except  the Z direction 

ETMY  .

Conclusion: up to 20 Hz this set up is good.

I didn't really appreciate this measurement until just now. IF you can save the DTT .xml file with all the traces in it (i.e. NOT just the plots), we should save this data for comparison plotting later. Perhaps Gautam can post the gzipped xml file for you into the log.

The accelerometers don't read any real noise below ~3 Hz, so we can't judge the difference down low, but this seems like a good measurement in the 5 - 100 Hz band.

Unfortunately I had closed all the DTT windows that Steve had used for the earlier plots. So I took the spectra again - there may be minor differences given that this measurement was taken at ~11pm at night. Anyways, plots and the xml data file are attached.  

We got it! Traps are removed.

It rained hard yesterday. We have not had this strong downpoor for years. We got 0.7" and the roof did not leak.

I measured the guralp raw outputs and the TFs using the handheld unit and an FFT analyzer.

[Setup]

The handheld unit was connected to each guralp with the same cable which is confirmed t be functional with the Yend Guralp.

The signal for Z, N, and E directions are obtained from the banana connectors on the handheld unit. Each direction has mass, low gain velocity, and high gain velocity output. The PSDs of the signals were measured with an FFT analyzer. The transfer function from the mass signal to the low/high gain signals were also measured for each direction.

The adjustment screw for the E output of the Xend does not work. I had to tilt the Xend Guralp using the leg screws to bring the E signal to zero.

[Result]

Attachment 1: Raw voltage PSD for all outputs
Attachment 2: Comparison of the low gain vel outputs

- All of the mass output show similar PSDs.
- Low gain velocity outputs shows somewhat similar levels. I still need to check if the output is really the ground velocity or not.
- High gain velocity outputs are either not high gain, broken, or not implemented.

- We need to calibrate the low gain output using signal injection, huddle test, or something else.

Attachment 3: TFs between each mass output and the low or high gain outputs

- TFs between the mass signal and the low vel signals show the similar transfer functions between the channels.
- The high gain outputs show low or no transfer function with regard to the mass signals.
 

Johannes found dripping water at the vac rack. It is safe. It is not catching anything. Actual precipitation was only 0.62"

We have one calibration sheet of GUR- B, from 26 June 2008,    model CMG-T40-0008,  sn T4157       at  ETMY  east,  interface box input 1

I'm looking for calibration paper of GUR- A,                                model CMG-T40-0053,  sn T4Q17      at ETMX   south, interface box input 2

Calibration Data

All Guralp instruments and digitisers are provided with calibration documentation. Should you require a copy of calibration information for any product, email caldoc@guralp.com with the serial number of the product in the subject field and calibration information will be sent to you through email.

See data in the 40m wiki

Calibration of Guralp Seismometers

Objective

• Estimate transfer functions of Guralp A ( near ETMX) and Guralp B ( near ETMY)
• Calibrate the instruments by estimating Velocity Sensitity Parameter
• Convert previously measured Voltage Spectrum to Velocity Spectrum

Instruments Used

• Guralp CMG-40 T Seimometers  : Guralp A (Serial Number: T4Q17)
• Guralp CMG-40 T Seimometers  : Guralp B (Serial Number: T4157)
• Guralp Handheld Control Unit (HCU)
• FFT Spectrum Analyzer: Model SR785: 2 Channel Dynamic Signal Analyzer
• Oscilloscope: TDS 3014B
• Function Generator: DS 345

Procedure & Results

Sinusoidal current of known frequency and amplitude was injected to the Seismometer calibration coil using signal generator and handheld control unit & corresponding Magnitude and Phase response were recorded.  For  Guralp B, system response was also estimated with a FFT Spectrum Analyzer. 

Frequnecy Range: 0.1 Hz to 45 Hz.

Equivalent Input Velocity was derived from the Input Voltage measurements using the relation: v = V/ (2*pi*f*R*K) , V is the peak to peak Calibration Signal voltage, f is the calibration signal frequency, R is the calibration resistor and K is the feedback coil constant.  [See Appendix for R & K values]                                     

Velocity Sensitity at the required frequency is obtained by dividing the Output Response Voltage by the Equivalent Input Velocity.

The obtained Velocity Sensitivity is used to convert the recorded Volatge PSD to Velocity PSD as shown below. The obtained results are compared to gloabl high noise model [NHNM] and USGS New Low Noise Model [NLNM,Peterson 1993] which gives the lowest observed vertical seismic noise levels across the seismic frequency band. Plot legend NLNM shows both the high & low levels.

                                                                    Guralp A [X Arm] Low Velocity Output                                          

                                                                    Guralp B [Y Arm] Low Velocity Output                                          

                                                                            DTT Power Spectrum                                                             

Both the Seismometers were connected to the 40 M Control and Data Acquisition System (CDS) and Power Spectrum was estimated for the Vertical, North/South & East/West Channels using Diagnostic Test Tool (DTT) software.

Comments

•  The transfer function from Guralp A [ETMX] looks similar to that of Guralp B [ETMY] in both magnitude and phase but with a lower gain.                                                                                                                                                                                                  
• Velocity Sensitivity of Guralp A is comparable to the value provided in the Calibration Data Sheet [~ 400] for all the channels [Vertical, North/South, East/West] after 1 Hz. For Guralp B, Velocity Sensitivity is a factor of 2.5 higher [all channels] than the specification [~ 400] after 1 HZ.Below 1 Hz Sensitivity drops down for both sensors. I am not ruling out a missing common factor in the calculation, but anyway, test shows that Guralp B has ~2.5 times better Velocity Sensitivity than Guralp A.                                                                                                                                                               
• The Calibrated Seismic Velocity Spectrum for Guralp B is within the Globally Observed High and Low Noise Seismic Spectrum while Guralp A's Spectrum is more noisier above 1 Hz [Anthropogenic Activity normally contributes the most in 1 Hz to 10 Hz frequency band].                                                                                                                                                                                                                                                                          
• Concurrently acquired Power Spectrum using DTT [Diagnostic Test Tools] shows that Guralp A Spectrum behaves rather strangely. The system response seems to be completely different from the one we obtained locally using signal generator. While Guralp B functionality seems normal. One reason for this erratic beahvior might be faulty cables used for data acquisition from Guralp A. This needs to be verified.                                                                                                                        

Appendix

                                                                            CMG-40T Guralp A Calibration Sheet                                                           

Calibration Resistor: 51000

                                                                            CMG-40T Guralp B Calibration Sheet                                                           

Calibration Resistor: 51000 

Something seems not right. The Guralp response should be flat in velocity from 0.05-30 Hz. Why is there any feature at 1 Hz? Saturation of some kind?

It is worth wiping table top covers. Use isopropanol soaked lint free wipes.

Dan sealed the leak today.