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ID Date Authorup Type Category Subject
  741   Fri Jul 25 19:57:18 2008 JenneUpdatePSLRef Cav & PMC
"PMC is in, but is still being worked on. Leave it alone." ---Rana

Ref. Cavity is locked again. Still a work in progress. I think we're ready to mode match on Monday. ---Jenne
  746   Mon Jul 28 11:20:13 2008 JenneUpdatePSLWork on the FSS and Reference Cavity
[Yoichi, Jenne, Koji]

The Reference Cavity's saga continues....

Thursday, Yoichi and I worked to change the beam that we chose from the 2nd pass through the AOM, to the first order beam rather than the 2nd order beam (see elog #726). After choosing the correct beam, we get 29mW incident on the reference cavity (compared with 4mW before any work began). We adjusted the angle of the AOM in the plane of the table, and got up to 30.6mW. We adjusted the tip/tilt of the AOM and got to 30.7mW (the tip/tilt adjustment made a more significant difference in the work described in elog #726, but after that work, it was probably already pretty close to optimized). We noticed that for the above measurements, we had 2 beams through the Polarizing Beam Splitter and Waveplate (one very dim), so after excluding that beam, the power meter read 30.4mW. We adjusted the curved mirror a little, and got 30.8mW incident on the reference cavity.

We then put a triangle wave into the offset of the MC Servo Board using the "trianglewave <channel> <center> <amplitude> <period> <runtime>" command in a terminal screen. This changes the voltage to the VCO, and thus the frequency response of the AOM. We watch the diffracted spots from the second pass through the AOM, and confirm that the beam we have chosen is not moving, and all the others are. By symmetry, if we chose the first order beam after the first pass through the AOM, and then again chose the first order beam after the second pass, the resulting beam will not move with the frequency change of the AOM.

We saw 1.50V (Refl. PD, unlocked) on the 'scope after aligning the optics to make the newly chosen beam hit the input mirror of the reference cavity. Order of operations for this alignment:
  • Recenter the beam on the 2 lenses that are just after the PBS and the waveplate
  • Adjust pitch and yaw of the two steering mirrors until the beam reflected off the input mirror of the reference cavity is parallel to the incident beam
    • Use a sensor card to check the alignment of the incident and reflected beams, and adjust the steering mirrors to get the alignment close
      • Note the amplitude of the DC output of the Refl. PD with the iris completely open. Close the iris until the signal decreases by ~50%, then adjust the steering mirrors until the original amplitude is regained. Repeat until the iris can be almost completely closed but the Refl. PD signal doesn't change
    • Watch the DC output of the Refl. PD, and maximize the signal on a 'scope
    • Sweep the PZT of the laser using a function generator into the RAMP input on the FSS board (~10Vpp at ~1Hz), OR sweep the temperature of the laser using the trianglewave function on the SLOW FSS channel (amplitude~0.5, period~50)
    • Watch the modes that resonate in the cavity, and adjust pitch and yaw of the steering mirrors to get closer to the TEM00 mode
    • When the TEM00 mode appears in the sweep, stop the sweep, and lock the cavity
    • Watch the DC output of the Transmitted PD, and maximize the signal on a 'scope
  • Celebrate!

After all of this adjusting,
Refl. PD (unlocked) = 1.48V
Refl. PD (locked) = 680mV
Trans. PD (locked) = 6.28V
Power reflected (unlocked) = 26.28mW
Power transmitted (locked) = 13.89mW
Thus, 53% transmission

Next: check the amount of power transmitted by reducing the amplitude of the RF modulator. This reduces the amount of power used by the sidebands, and so should increase the transmission.
Power incident = 27mW
Power transmitted = 17.2mW
Thus, 64% transmission
We then put the RF modulator back where it was originally.

We then replaced the lens mounts for the f=802 and f=687 lenses between the AOM and the reference cavity, to the new mounts that Yoichi bought. Koji helped me realign into the reference cavity, and we got:
Refl. PD (unlocked) = 1.48V
Refl. PD (locked) = 880mV
Trans PD (locked) = 4.64V
Power incident = 26.97mW
Power transmitted = 10.39mW
39% transmission
Since more mode matching etc. is in the works, we left this for the night.

On Friday, we changed the setup of the cameras and PDs for both reflection and transmission, to avoid saturating the PDs and cameras.

On the Refl. side of the reference cavity, we put a W2-PW-1025-UV-1064-45P pickoff between the last mirror and lens before the camera and PD. We moved the camera to the pickoff side of the new optic. We then replaced teh 45UNP beam splitter that split the beam between the PD and the camera with a Y1-1037-45P highly reflective mirror, and put the PD in the old camera location.

On the Trans. side of the ref. cavity, we replaced the BSI-1064-50-1025-45S with a W2 pickoff, and replaced the Y1-1037-45-P highly reflective mirror with the 50/50 beam splitter that was replaced by the W2.

Now we have:
Refl. PD (unlocked) = 1.68V
Refl. PD (locked) = 640mV
Trans PD (locked) = 4.24V
Power incident = 25mW
Power transmitted = 14.48mW
58% transmission

Koji pointed out that when remounting, I had put the f=802 lens ~2cm away from its original position (along the z-axis), so I moved the lens back to where it should be, and realigned into the reference cavity. Since Rana was working on the PMC at the same time, the laser was turned down by about a factor of 100, so my starting measurements were:
Refl. PD (unlocked) = 23.6mV
Refl. PD (locked) = 10.2mV
Trans PD (locked) = 56mV
Power incident = 0.35mW
Power transmitted = 0.16mW
46% transmission

Since it was late on Friday by the time everything was realigned into the ref. cavity (I'm still working on my optics aligning skills), I forgot to measure the transmission after all of my work. I'll do that today (Monday) as soon as Sharon/Koji are done working with the IFO this morning. Also, I'll put up before/after pictures as soon as I find the camera...it seems to have walked off.

UPDATE:
Ref. Cav. measurements after Friday's alignment (and after turning the laser power back up to normal):
Refl. PD (unlocked) = 1.58V
Refl. PD (locked) = 304mV
Trans PD (locked) = 3.68V
Power incident = 24.96mW
Power transmitted = 16.45mW
66% transmission


To do: Start the actual mode-matching into the reference cavity.
  754   Tue Jul 29 11:50:01 2008 JenneUpdateEnvironment5.6 Earthquake
Earthquake Details
Magnitude 5.6
Date-Time

* Tuesday, July 29, 2008 at 18:42:15 UTC
* Tuesday, July 29, 2008 at 11:42:15 AM at epicenter

Location 33.959N, 117.752W
Depth 12.3 km (7.6 miles)
Region GREATER LOS ANGELES AREA, CALIFORNIA
Distances

* 3 km (2 miles) SW (235) from Chino Hills, CA
* 8 km (5 miles) SE (127) from Diamond Bar, CA
* 9 km (5 miles) NNE (23) from Yorba Linda, CA
* 11 km (7 miles) S (178) from Pomona, CA
* 47 km (29 miles) ESE (103) from Los Angeles Civic Center, CA

Location Uncertainty horizontal +/- 0.3 km (0.2 miles); depth +/- 1.3 km (0.8 miles)
Parameters Nph=144, Dmin=8 km, Rmss=0.42 sec, Gp= 18,
M-type=local magnitude (ML), Version=1
Source

* California Integrated Seismic Net:
* USGS Caltech CGS UCB UCSD UNR

Event ID ci14383980

All the watchdogs tripped. I'll put them back after lunch, after the optics have had time to settle down.
  811   Thu Aug 7 17:32:23 2008 JenneUpdateSUSAfternoon PRM activities
Rana, Jenne, Yoichi, Dmass

After Yoichi confirmed this morning that the wire was in both grooves, Rana attempted to lift the PRM a tiny bit, and twist it around (very gently of course) to see if we could make the wire slip back to its nominal position underneath the optic. On the first attempt, the wire ended up slipping the wrong way, causing slightly more tilt. On another attempt, the wire came out of the groove nearest the chamber door by about 0.5mm. We got the wire back in the groove by slightly lifting the optic, and pushing the wire back in. Then, on further attempts at making the wire slip back to its nominal position, the wire came out of the groove farthest from the chamber door. It is very difficult to get at that side of the PRM, because the table is crowded, and it is on the far side of the optical table from the chamber door. We decided to pull the PRM out of the chamber. Rana clamped the mirror into its cage using the earthquake stops and removed the OSEMS, and then we pulled the mirror out. We put it on a cart that was covered with foil and had a little foil house for the optic cage. We rolled the mirror+cage over to the flow bench at the end of the y-arm.

We saw that the wire is no longer even on the standoff (~3mm away from the groove) on the side that was farthest from the chamber door.

Since we have not confirmed that we have spare wire and spare magnets (and due to the time of day), we have decided to cover the cage with some foil, while it is sitting on the flow bench, and we'll fix the wire in the morning.
  818   Fri Aug 8 17:54:52 2008 JenneUpdateSUSStandoffs and Guide Rods
After closer inspection of other small optics, it is clear that the guide rods should be above the standoffs on our small optics. Yoichi took a picture of the SRM that shows this clearly. This makes sense since the tension of the wire will make the standoff 'want' to go up during pre-epoxy adjustment, so the guide rod prevents the standoff from popping up and out.

Looking at the side of the PRM without the groove, it looks like there is lots of space between the guide rod and the alignment etch in the glass, so we can just place a standoff directly under the guide rod that is present.

A spare standoff is being shipped tomorrow morning, so we should have it by Monday for installation on the PRM.
  826   Mon Aug 11 19:09:28 2008 JenneDAQPEMSeismometer DAQ is being funny
While looking at the Ranger seismometer's output to figure out what our max typical ground motion is, Rana and I saw that the DAQ output is at a weird level. It looks like even though the input to the DAQ channel is being saturated, the channel isn't outputing as many counts as expected to Dataviewer.

Sharon and I checked that the output of the seismometer looks reasonable - sinusoidal when I tap on the seismometer, and the the output of the SR560 (preamp) is also fine, and not clipping. If I stomp on the floor, the output of the SR560 goes above 2V (to about 3V ish), so we should be saturating the DAQ, and getting the max number of counts out. However, as you can see in the first figure, taken when I was tapping the seismometer, the number of counts at saturation is well beneath 32768counts. (16 bit machine, so the +-2V of the DAQ should have a total range of 65536. +2V should correspond to +32768counts.) The second figure shows 40 days of seismometer data. It looks like we saturate the DAQ regularly.

I did a check of the DAQ using an HP6236B power supply. I sent in 1V, 2V and 2.2V (measuring the output of the power supply with a 'scope), and measured the number of counts output on the DAQ.

Input Voltage [V]Counts on DataviewerExpected counts from 16 bit machine
11898316384
22933132768
2.22934732768


I'm not sure why the +1V output more than the expected number of counts (unless I mis-measured the output from the power supply).

Moral of the story is...when the DAQ is saturated, it is not outputting the expected number of counts. To be explored further tomorrow...
  829   Tue Aug 12 19:48:24 2008 JenneUpdateIOOPRM standoff is in....mostly
Yoichi, Jenne

The missing PRM standoff is now partially installed. The standoff is in, and the wire is in the groove, but we have not finished adjusting its position to make the PRM stand up straight. It turns out to be pretty tricky to get the position of the standoff just right.

We have set up a HeNe laser as an oplev on the flow bench (which we checked was level) in the clean assembly room, and are using it to check the pitch of the mirror. We set a QPD at the height of the laser, and are looking at the single-reflected light. When the single-reflected light is at the same height as the center of the QPD, then the mirror is correctly aligned in pitch. (Actually, right now we're just trying to get the single-reflected light to hit the diode at all...one step at a time here).

We'll continue trying to align the PRM's standoff in the morning.
  837   Thu Aug 14 19:35:54 2008 JenneSummaryIOOPRM in the chamber, ready to pump!
Rob, Yoichi, Jenne, Steve

Summary: Everything is back in the chamber, we just need to put on the big doors, and start pumping in the morning.

After letting the PRM's standoff epoxy cure overnight, it was time to put the optic back in the BS Chamber. Rob put the optic cage back in the chamber, as close to the guide points that Rana had placed as possible. A handy technique was discovered for pushing the cage into place: put a long screw into the table, leaving an inch or so above the table, then use that as a push-off point so that you can push the base of the cage with your thumb. According to Rob, this is probably just about as effective as using a pusher-screw.

The guides were helpful in getting the PRM back to its original position, but one of them was placed in such a way that it could move when pushed against. The clamp that was used as a guide point was placed with one of the screws half on the edge of a hole, so that when the cage was pushed against the guide point, that screw could wiggle around, causing the clamp to rotate thus no longer being a definite guide point.

Just after putting the PRM in place, Rob found the standoff that had gone missing. (see elog #835)

Once the PRM was back in place, we put the OSEMs back, and reinstalled the satellite boxes that had been removed (PRM's, which Ben has fixed - an op-amp was blown, and BS's, which we used over in the clean room with the spare OSEMs). We found a problem with the LR PRM OSEM reading on Dataviewer. It was saturating when the OSEM was just sitting on the table, with nothing between the LED and the sensor. We measured the output from the satellite box with the octopus cables, and measured 2.3 volts, which is too much for the DAQ. It seems fine when we install it in the cage, and the magnet is blocking part of the light. We should investigate the gain of the satellite box when convenient. This is not something that needs to be done prior to pump-down. Also, when we put an allen wrench to block the light while checking which OSEM was which, we noticed that the Dataviewer reading would go down to -2V, then come back to 0V when the light was completely blocked. This may be some incorrect compensation for some whitening. Again, we should look into this, but it is not terribly time-sensitive.

Once the OSEMs were centered, we tried to turn on the damping for the PRM. This was successful, so we are confident that we have put all of the OSEMs back in their correct places.

We found that we were easily able to get the PRM's oplev back on the QPD, so we ~centered the oplev, and then centered all of the PRM's OSEMs. This assumes that the oplev was in a good place, but I think we've determined that this is the case.

We did the same thing for the SRM and the BS, to check the OSEM values before we close up for good. We found that some of the SRM OSEMs were reading low (magnet too far in), and that all of the BS OSEMs were low, perhaps as if the table were tilted a tiny bit after removing and replacing the weight of the PRM. We recentered all of the OSEMs for both of these optics.

We checked that all of the pigtails for the PRM OSEMs were anchored to the PRM cage using some copper wire as tie-downs.

We checked that all of the earthquake stops were within 1mm or so of each of the 3 optics in the BS chamber. The SRM's earthquake stops were fairly far out. One of the bottom ones was far enough that when Yoichi turned it the wrong way (accidentally), it fell out. He put it back in, and adjusted all of the earthquake stops appropriately. This 1mm distance comes from Seji, and the specs for the optics' cages.

We did a look-through of the chamber, and took out all of the tools, and other things that were not bolted down to the table.

We have left the damping of the PRM off for the night.

To do: put the doors back on, and start the pump down.
  851   Tue Aug 19 13:12:55 2008 JenneUpdateSUSDiagonalized PRM Input Matrix
NOTE: Use the values in elog #860 instead (20Aug2008)

Using the method described in LIGO-T040054-03-R (Shihori's "Diagonalization of the Input Matrix of the Suspension System"), I have diagonalized the input matrices for the PRM.

Notes about the method in the document:
  • Must define the peak-to-peak voltage (measured via DataViewer) to be NEGATIVE for PitLR, PitLL, YawUR, YawLR, and POSITIVE for all others
  • As Osamu noted in his 3 Aug 2005 elog entry, all of the negative signs in equations 4-9 should all be plus.

New PRM Input Matrices:

POSPITYAW
UL1.0001.0001.000
UR1.18771.0075 -1.0135
LR0.8439 -0.9425 -0.9653
LL0.9684 -1.05001.0216
  860   Wed Aug 20 12:04:47 2008 JenneUpdateSUSBetter diagonalization of PRM input matrix
The values here should replace those in entry #851 from yesterday.

After checking the results of the input matrix diagonalization, I have determined that Sonia's method (described in LIGO-T070168) is more effective at isolating the eigenmodes than Shihori's method (LIGO-T040054).

So, the actual new PRM input matrices are as follows:

POSPITYAW
UL0.96781.0000.7321
UR1.0000.8025 -0.9993
LR0.7235 -1.1230 -1.0129
LL0.6648 -1.04521.0000


Attached are plots of the spectra of the eigenmodes, using both Shihori's and Sonia's methods. Note that there isn't a good way to get the side peak out of the eigenmodes.

I've put these into the SUS-PRM MEDM screen.
  869   Fri Aug 22 10:39:41 2008 JenneUpdateSUSTaking Free Swinging spectra of PRM, SRM, ITMX, BS
I'm taking free swinging spectra of PRM, SRM, ITMX and BS, so I've turned off their watchdogs for now. I should be done around 11:15am, so I'll turn them back on then.
  874   Mon Aug 25 10:07:35 2008 JenneUpdatePSLNumbers for the PMC servo board (Re: entry # 873)
Jenne, Rana

These are the numbers that go along with Rana's entry #873:

The existing notch in the PMC servo is at 31.41kHz.

The power spectrum of the PMC has a peak at 14.683kHz when it is just sitting on the PSL table (no extra mass). When we put a pile of steel and aluminum (~20lbs) on top of the PMC, the body resonance moves to 14.622kHz, but is decreased by about 40 dB!

Rana has ordered a lead brick + foil that should arrive sometime this week. To complete the mechanical part of this installation, we need to extend the earthquake mounts around the PMC so that the lead brick can't fall off of the PMC onto the rest of the table.
  878   Mon Aug 25 12:13:49 2008 JenneUpdatePSLBroken PMC Servo Board
I broke the PMC servo board (on accident).

I was trying to measure the resistance of the extra resistor that someone put between the board and the HV OUT connector, since this is part of an RC filter (where C is the capacitance of the PZT on the PMC) that I need to know the values of as part of my mission to make a 14.6kHz notch for the PMC body mode. The resistance is 63.6k. I had to pull the board to get in to measure this resistance.

This resistor between the board and the center pin of the panel-mount HV OUT connector made a rigid connection between the board and the panel. When I was putting the board back in, I must have strained this connection enough that it broke. We don't have any of the same kind of resistor here at the 40m, so I'm waiting until after lunch to go to Wilson house and see if they've got any. The IFO is down until I get this sorted out.
  879   Mon Aug 25 14:18:36 2008 JenneUpdatePSLPMC servo board is fixed
The PMC servo board is back in place, all fixed up with a shiny new resistor. The PMC locks, and the MC locks (I'm not saying anything either way about how long the MC will stay locked, but it is locked for now). The resistor is connected to the connector using a short piece of wire, so this problem won't happen again, at least with this connector on this board.
  886   Tue Aug 26 12:00:45 2008 JenneSummaryPEMTransfer function of Ranger seismometer
This finishes up the calibration that Rana started in elog # 881.

The calibration of the Ranger seismometer should also include:
2 zeros at 0 Hz
2 poles at 1.02 Hz

This comes from finding the transfer function between the mass's motion and the motion of the ground.
    ..
m * x  = (x_G - x) * k  + d(x_G - x) * b
                          dt

where
  • m = mass
  • x = displacement of the mass
  • x_G = displacement of the ground
  • k = spring constant
  • b = damping constant

This gives
x               w0^2  +  i*w*w0/Q
----    =    -----------------------
x_G           w0^2 + i*w*w0/Q - w^2

where
  • w0 = sqrt(k/m) = natural frequency of spring + mass
  • w = frequency of ground motion
  • Q = q-factor of spring + mass system = 1/2 for critically damped system

The readout of the system is proportional to
d  (x - x_G)          (    w0^2  +  i*w*w0/Q          )    .                    w^2               .
dt                 =  (  -----------------------  - 1 ) * x_G   =      ----------------------- * x_G
                      (   w0^2 + i*w*w0/Q - w^2       )                w0^2 + i*w*w0/Q - w^2
Since we read out the signal that is proportional to velocity, this is precisely the transfer function we're looking for. With w0 = 1.02 Hz and Q = 1/2 for the critically damped system, we have 2 zeros at 0 and 2 poles at 1.02.
  921   Thu Sep 4 10:13:48 2008 JenneUpdateIOOWe unlocked the MC temporarily
[Joe, Eric, Jenne]

While trying to diagnose some DAQ/PD problems (look for Joe and Eric's entry later), we unlocked the PMC, which caused (of course) the MC to unlock. So if you're looking back in the data, the unlock at ~10:08am is caused by us, not whatever problems may have been going on with the FSS. It is now locked again, and looking good.
  924   Thu Sep 4 14:43:58 2008 JenneUpdatePSLPMC Open Loop Gain
I have measured the PMC's open loop gain. UGF is 629.7Hz, with a phase margin of 53 degrees.

I injected into FP2 on the front panel, and measured MixOut/Source from 100Hz to 100kHz using the SR785. I did this both when the loop was open, and when the loop was closed (open the loop by enabling FP1, which breaks the loop).

We have 2 transfer functions involved: The actual open loop gain of the PMC servo loop (G1), and the gain between FP2 and the MixerOut monitor point (G2). This gives us:

TF(closed loop) = G2*(1+G1)
TF(broken loop) = G2

G1 = TF(closed)/TF(broken) - 1

This G1 is the final open loop gain, and it is plotted below.
  978   Mon Sep 22 18:54:54 2008 JenneUpdatePSLPMC transfer functions with various brick-on-top configurations
Attached below is a graphical summary of different things that I have tried putting on the PMC to reduce the noise in the loop. The motivation behind these measurements is the current inability here at the 40m to increase the UGF of the PMC. This is part of a broader ISS loop/gain/noise problem that we are having, which is causing Rob's locking efforts to have trouble. (The ISS is next on the to-do list, after we find the best configuration for the PMC, if we are still having problems). Right now, it looks like we are being limited by the gain of the PMC (as mentioned by Rana in elog #968).

Anyhow, Rana and I had noticed that piling heavy things on top of the PMC seemed to reduce the noise. What follows are the transfer functions that I took with the different items on top of the PMC, so that we can compare their effects:
  • Nothing on the PMC (like it used to be)
  • New ~14kg lead brick wrapped in copper foil on top of the PMC
  • A stack of a piece of aluminum, a chunk of steel, and then the lead brick on top of the PMC
  • The lead brick + Rob pushing on top of the PMC

Unfortunately, I need to retake the power spectra in these configurations, but from eye-balling it, as one might expect, pushing on the PMC with a hand added more noise than the nominal nothing-on-PMC configuration.

Also unfortunately, none of these configurations seems to have significantly helped our noise reduction situation. We need a new plan. Rana is currently trying out some other configurations, including just aluminum+brick.

Attached is an open loop gain TF from 100Hz - 100kHz. Below that is a zoomed-in version from 5kHz - 30kHz. As you can see more clearly in the zoomed in version, the notch that Rana put onto the board at ~14.5kHz is working, but we need to make the notch deeper, to catch more of that 14.5kHz peak. We're going to try removing the resistor or reducing it's value in the RLC filter on the board (see elog #906). Also, we see that there is a giant peak at 18.3kHz. This is probably much more limiting to our stability at this point than the 14.5kHz peak. We need to add another filter to take care of this, or find another way to reduce this peak. Note that it is present even when there is no brick on the PMC, so it is not an artifact of the new brick.
  995   Fri Sep 26 00:19:54 2008 JenneUpdatePSLFilter-action with the PMC
Written, but not posted on 24Sept2008:



PMC adventures for this evening



Today's mission was to make more progress on increasing the bandwidth of the PMC servo.



First order of business was to improve the performance of the 14.6kHz notch that Rana put in the PMC servo board a few weeks ago to remove the 14.6kHz body mode resonance of the PMC. Looking at the zoomed in TF that I posted Monday (elog #978), we see that there is still a remnant of a peak near 14.5kHz. A first gut-reaction is that the notch is not tuned properly, that we have just missed the peak. As previously noted in the elog, the peak that we are trying to notch out is at 14.68kHz (elog #874). By unlocking the PMC and measuring the transfer function between FP2 and OutMon (OutMon is the monitor for the high voltage going to the PMC's PZT), I measure the transfer function of the notch, and find that it is notching at 14.63kHz. So we're a teensy bit off, but the Q of the notch is such that we're still getting improvement at the peak frequency. After checking that we are hitting the correct frequency, I put a short (just some wire) around R21, which is the R in the RLC notch filter, to increase the depth of the notch. At the peak frequency of 14.68kHz, we see a 2.5dB improvement of the notch. At the actual notch frequency of 14.63kHz, we see a 3.2dB increase in the depth of the notch. So, shorting R21 helped a little, but not a lot. Also, it's clear that we don't get that much more improvement by being on the resonant frequency, so there's no need to go in and tune the notch on the board.



Second order of business was to investigate the 18.34kHz peak in the transfer function. (Rana spent some time Monday night measuring this peak, and determined that it was at 18.34kHz) We decided that the best plan was to re-implement the Pomona Box notch filter that had previously existed to remove a higher frequency body mode, but tuned for the 18.34kHz mode. I am still not entirely sure what this mode is, but clearly it's a problem by about 20dB (on the TF, the next highest peak is 20dB below the 18.34kHz peak). Unfortunately, while the components should, by Matlab calculations, give me an 18.3kHz notch, I ended up with something like a 21.7kHz notch. This notch is approximately -30dB at 21.7kHz, and -20dB at 18.3kHz. I still need to take transfer functions and power spectra of the PMC servo with this new filter in place to (a) confirm that it did some good, and (b) to determine how important it is that the notch be right-on. More likely than not, I'll take the filter out and fiddle with the capacitors until I get the correct notch frequency.



Third on the list was to lock everything back up (FSS, PMC) after my tinkering, and see what kind of gain we get. Rob and I fiddled with the PMC gain, and it looks like the servo oscillates just before we get up to the max slider gain of 30dB. Looking at the power spectra in DTT, we do not see any significant peaks that suggest oscillation, so it is likely that there is some investigation to be done at frequencies above the 7kHz that we were able to look at with DTT (which isn't surprising, since all of this work has been at 14kHz and higher).



A final note is that we see a feature around 9kHz in the transfer function, and it is not at all clear where it comes from. At this time, it does not seem to be the dominant feature preventing us from increasing the gain, but at some point if we want the bandwidth of the PMC servo to be 10kHz, we'll have to figure this one out.



Still on the PMC todo list:


  • Measure the new transfer function, see if 18.34kHz peak is reduced

  • Tune Pomona Box notch filter to 18.3kHz instead of the current 21.7kHz

  • Retake power spectra of different items on top of PMC, compare to see if there is any one configuration that it obviously better than the others.

  • Find out why the PMC still oscillates when we try to take it up to the max slider gain, and fix it.

PS, is anyone else having trouble getting to the elog from laptops on other parts of the Caltech network (but not LIGO network)? My laptop won't go to the elog, but I can get to the rest of the internet using the Caltech wireless. My computer stopped seeing the elog on Tuesday or so. Joe, do you have any inspiration? Thanks.
  1000   Fri Sep 26 18:35:17 2008 JenneUpdatePSLPMC filter is out for tuning
The PMC's new Pomona Box filter is out for tuning. I'd like to get the notch right on the 18.3kHz, rather than being off in 21.7kHz land.
  1002   Fri Sep 26 19:18:39 2008 JenneUpdateIOOMC2 is having a bad day
As Steve mentioned earlier in today's elog, MC2 keeps ringing up for no clear reason. It is definitely only MC2 that is ringing up, since it's sensors will read several hundreds of counts, while all the other optics are at regular 2 counts and below on the Watchdog screen.

Preliminary investigation results: Around the time of these "kick up" events, the Ranger seismometer does not see any motion, nor does the set of accelerometers under the MC1 chamber. The set of accelerometers under the MC2 chamber do see activity that is at the same time as these events. These events are not caused just by someone walking around, since Rana went inside and clunked around near MC2 while I watched the sensor levels. MC2's watchdog did not trip.

For further investigation: Why is it that only the MC2 accelerometers are seeing the motion? Similarly, why is MC2 the only optic being kicked? Has anyone done anything lately to the MC2 stack?
  1010   Tue Sep 30 19:50:27 2008 JenneUpdatePSLQuicky Summary - more details later
Quicky summary for now, more details later tonight / tomorrow morning:

PMC notch: It's tuned up, but it is out, and it is staying out. It looks like the 18.3kHz junk isn't being helped by the brick, in fact the brick makes it worse. And the notch isn't enough to make the peak go away. Rana's and my conclusions about the PMC: the 18.3kHz resonance is associated with the way the PMC touches its mount. Depending on where we push (very gently, not much pressure) on the PMC, we can make the peak come and go. Also, if the PMC happens to be set nicely on its ball bearings, the peak doesn't appear. More notes on this later.

PMC's RF modulation depth: Since with the PMC's brick off, and the PMC sitting nicely on its ball bearings, we don't see any crazy oscillations, we were able to take the gain slider on the PMC screen all the way up to 30dB. To give us more range, we changed the modulation depth of the RF to 2V, from its previous value of 1V.

Phase of PMC servo: Since the phase of the PMC servo hasn't been set in a while, I eyeballed it, and set the phase to: Phase Flip = 180, Phase Slider = 4.8000 . I measured many points, and will plot a calibration curve later.

I also measured the actual value of the RF out of the PMC's LO board, when changing the RF output adjust slider. Again, will post the calibration later.

The attached PNG shows the PMC spectra from now and from Aug. 30 (ref). As you can see there's been some good reduction in the acoustic noise (red v. orange). The large change in the error signal is because of the much higher gain in the servo now. We'll have to redo this plot once Jenne measures the new UGF.
  1089   Fri Oct 24 21:49:15 2008 JenneConfigurationPEMShort Seismometer Cable
Bad news regarding the cable that goes between the Guralp seismometer and the box that I've been working on: it's too short by about a factor of 2. Dang it. I've placed the seismometer underneath the Beam Splitter Chamber (where it needs to go), and started running the cable toward the ADC rack where box was planned to go, and as Rana guessed earlier tonight, the cable isn't nearly long enough. We have some options: the seismometer can go back into the half-height rack near the BS, SRM, PRM oplev's optical table where I think it used to be, or it can go into the rack with the Kepco high voltage power supplies and the laser's supply. The cable won't reach any farther than that.

I think that we can just add BNC extensions onto the octopus cable that Bob made for the Guralp box, so all we need to figure out after we decide on a rack is the power for the box.
  1100   Wed Oct 29 12:54:28 2008 JenneUpdatePEMCalibrated Guralp Noise compared to average ground motion
Here is a calibrated noise plot of the Guralp seismometer box. This is the same noise measured on Friday, measured at TP3 (just after the first gain stage), with the inputs shorted.

The Guralp calibration is:
                TP3 noise
noise in m/s = -------------------
                 10 * 802(V/(m/s))
The 10 is from the gain of 10 between the output of the seismometer and the input of the breakout box, and the 802 V/(m/s) is from the calibration data that came with the seismometer.

From elog 881 by Rana, in the ~1-50Hz band, the calibration of the Ranger seismometer is 488*10^6 counts/(m/s). Using DataViewer, I estimated that the nighttime ground motion measured by the Ranger is ~3500 counts, and the max daytime ground motion is ~8000 counts. This is what was used for the nighttime/daytime lines in this plot.

It seems like the noise of the Guralp box is fine just as it is, and we don't need to worry about replacing the first gain stage (differential instrumentation amp) with a lower-noise op-amp, since at even the lowest freqs, we have almost a factor of 100 at night, and better than that at higher freqs.

NOTE about the plot: the legend isn't showing the correct colors for the night and day motion - obviously the nighttime motion is the lower RED line, and the day is the higher GREEN line.

Yet another note: When I was measuring the counts on the Ranger, I forgot to subtract the mean, so these numbers are overestimating the ambient ground motion. The blue curve is correct however.
  1131   Wed Nov 12 11:36:13 2008 JenneUpdatePEMGuralp Breakout Box is ~50% hooked up
The Guralp box is about halfway hooked up now. The seismometer is under the BSC, and the long cable from the seismometer to the breakout box is connected to "Guralps 1 Input" on the front panel. This corresponds to the set of 3 channels that Caryn stuffed with the new fancy-pants resistors few weeks ago. (When we finally get the other Guralp back from the company, we'll have to stuff the next set of 3 channels).

The Breakout Box is on the very top of 1Y1, sitting on top of the black power supplies. This should be fine, but it's pretty toasty hot up there, so if we find that there are problems with running the box at higher-than-room-temperature, step 1 will be to find a new spot for the box. (I'm not at this time anticipating a problem, but you never know....) Steve put a little foot between the Guralp box and the power supply to get some air circulation.

The ADC Octopus cable that Bob made is connected, and going up through the top of the rack. I am now going on a BNC cable hunt to extend this cable over to the PEM ADC. The PEM ADC is in 1Y7, so I'll need some medium-long BNC cable to get there.

The power cable is also ready to be connected to the rack's +/- 15VDC. I'll talk to Bob about getting this done.

Next step: pick some channels on the PEM ADC, and create them in the .ini files
  1135   Fri Nov 14 17:41:50 2008 JenneOmnistructureElectronicsSweet New Soldering Iron
The fancy new Weller Soldering Iron is now hooked up on the electronics bench.

Accessories for it are in the blue twirly cabinet (spare tips of different types, CD, and USB cable to connect it to a computer, should we ever decide to do so.

Rana: the soldering iron has a USB port?
  1141   Mon Nov 17 16:59:22 2008 JenneUpdatePEMSeismometer hooked up, reading channels on DataViewer
Alberto, Jenne

The Guralp Seismometer is (finally) hooked up to the PEM ADCU. Alberto helped me make channels in the c1pem1 .ini file, which correspond to:

Guralp1 VERT = channel 9 on PEM ADCU = C1:PEM-SEIS_MC1_VERT
Guralp1 NS = channel 10 on PEM ADCU = C1:PEM-SEIS_MC1_NS
Guralp1 EW = channel 11 on PEM ADCU = C1:PEM-SEIS_MC1_EW

We also renamed the Ranger seismometer's channel to C1:PEM-SEIS_MC2_Y from C1:PEM-SEIS_MC1_Y, since tomorrow I'll move the Ranger Seismometer to be underneath MC2's chamber (it's currently sitting somewhere in the middle of the Mode Cleaner).


I can see the VERT and NS channels with dataviewer, but EW looks dead. I need to figure out if this is a bad cable thing, or if the ADC channel is no good, or if something in the box on that channel is no good. All 3 channels were tested and working after all the soldering was completed by Caryn, but something may have come undone while putting the box into its new place in the top of 1Y1. (In dataviewer, it looks like the EW channel is just floating, and not connected to anything.)

Plan of Attack:
* figure out why EW looks dead on Dataviewer
* redo Rana's static Wiener filter analysis, now that we have 2 seismometers (1 Ranger and 1 Guralp)
* work on adaptive Wiener filtering with the Guralp
  1152   Fri Nov 21 16:52:48 2008 JenneUpdatePEMGuralp seismometer's Channel Problems are solved
PROBLEM noticed earlier this week: It looked like one of the seismometer channels (VERT-1) wasn't working, no matter how I put which channel into which input of the PEM ADCU. Watching the channel on Dataviewer, it looked like the ADC was measuring VERT-1 to be zero (actually measuring zero, not digital noise-type zero). I had checked the ADC by putting in a sine wave with a function generator, and saw on Dataviewer the wave I expected, so I knew that I had the correct channel, and that the channel was good.

SOLUTION: This afternoon I took the box out of the rack and opened it up. As soon as I opened it, I saw that I had left something inside the box which was causing the problem. Back when we were measuring the noise of the box, to ensure that it is lower than the ADC's noise, Rana and I had shorted the test points on the input of the VERT-1 channel with a little piece of wire. It turns out that I had closed up the box without remembering to remove the wire.

CONCLUSION of the story: I took out the piece of wire, and now all three seismometer channels (VERT-1, N/S-1, E/W-1) all work, and all detect me jumping around near the BSC. Since the seismometer breakout box reads a differential measurement, and since the input test points were connected, it was indeed measuring zero. Zero equals zero is all well and good, but it's even better now that it's measuring actual seismic motion.
  1153   Fri Nov 21 17:27:47 2008 JenneUpdatePEMGuralp noise measurement
Here is the data from the Guralp Seismometer for the past day or so, before I fixed the VERT-1 channel. The NS and EW show what's going on in the world, and VERT is measuring essentially the noise of the box, through the ADC, in counts.
  1174   Thu Dec 4 13:49:39 2008 JenneUpdatePEMMore of: Comparing Wiener subtraction using different sensors
Here is another version of the same type plot I put in the elog yesterday. This plot is looking at the 7200 seconds after 04Dec2008 08:45:00 UTC. This time was last night, when there was no crazy seismic activity, and well after the Ranger seismometer was moved to its new place under MC2.

This plot includes all possible combinations of the accelerometers, Guralp seismometer and Ranger seismometer (taking all 6 accelerometers as a set, and all 3 Guralp channels as a set). It is good to see that for the set of traces which do not include the accelerometers - brown, dark green and light blue - the subtraction at higher frequencies isn't all that great. Thus, the accelerometers are doing their job, and work well with the Wiener subtraction.

Still under investigation is why we don't see a whole lot of improvement at low frequency.
  1275   Thu Feb 5 16:21:07 2009 JenneFrogsComputersBelladonna connects to the wireless Martian network again

Symptoms:  Belladonna could not (for a while) connect to the wireless network, since there was a driver problem for the wireless card.  This (I believe) started when Yoichi was doing updates on it a while back.

The system: Belladonna is a Dell Inspirion E1505 laptop, with a Broadcom Corporation Dell Wireless 1390 WLAN Mini-PCI Card (rev 01)

Result:  Belladonna now can talk to it's wireless card, and is connected to the Martian network.  (MEDM and Dataviewer both work, so it must be on the network.)

 

What I did:

0.  Find a linux forum with the following method:  http://www.thelinuxpimp.com/main/index.php?name=News&file=article&sid=749

The person who wrote this has the exact same laptop, with the same wireless card.

1.  Get a new(er) version of ndiswrapper, which "translates" the Windows Driver for the wireless card to Linux-ese.  Belladonna previously was using ndiswrapper-1.37.

$wget http://nchc.dl.sourceforge.net/sourceforge/ndiswrapper/ndiswrapper-1.42.tar.gz

2.  Put the ndiswrapper in /home/controls/Drivers, and installed it.

$ndiswrapper -i bcmwl5.inf  3.  Get and put the Windows driver in /home/controls/Drivers/WiFi

$wget http://ftp.us.dell.com/network/R140747.EXE
4. Unzip the driver $unzip -a R140747.EXE

5.  Make Fedora use ndiswrapper

$ndiswrapper -m

$modprobe ndiswrapper

6. Change some files to make everything work:

/etc/sysconfig/wpa_supplicant      CHANGE FROM: DRIVERS="-Dndiswrapper"     CHANGE TO: DRIVERS="-Dwext"

/etc/sysconfig/network-scripts/ifcfg-wlan0      CHANGE FROM: BOOTPROTO=none      CHANGE TO: BOOTPROTO=dhcp

/etc/rc.d/init.d/wpa_supplicant        CHANGE FROM: daemon $prog -c $conf $INTERFACES $DRIVERS -B        CHANGE TO: daemon $prog -c$conf $INTERFACES $DRIVERS -B

6.  Restart things

$service wpa_supplicant restart
$service network restart

7.  Restart computer (since it wasn't working after 1-6, so give a restart a try)

8. Success!!!  MEDM and Dataviewer work without any wired internet connection => wireless card is all good again!

  1337   Wed Feb 25 11:48:02 2009 JenneUpdatePEMWiener filtering update - work on filtering some S5 DARM_CTRL data

Quick update on my wiener filtering status:

Joe has been helping me get on the GRID, so I now have  a grid certificate, and accounts on most/all of the clusters.

Joe also helped me get menkar to get S5 data so that I can do wiener filtering to the back-data. 

 

I've been running the wiener filtering algorithm, and right now, it doesn't do anything to improve the DARM_CTRL data.  I am confident that this is because something is funky in the wiener filtering algorithm somewhere.  The indicator of this is that the wiener filtering calculation takes the same amount of time (~95 seconds) to calculate a filter for 64 seconds of data as for 1 hour of data (both for N = 2000 taps). 

 

For reference, attached are my plots for the wiener filtering result for (1) 64 seconds of S5 data, and for (2) 3600 seconds of S5 data.

These plots were made using H1:DARM_CTRL as the signal to minimize, with 4 seismometers as the witness channels (EX_SEISX, EY_SEISY, LVEA_SEISX, LVEA_SEISY)

 

I'm working on figuring out what's going on with the filtering algorithm, and why it does work for C1:MC_L minimization, but does not work for H1:DARM_CTRL minimization.

 

 

 

  1392   Thu Mar 12 00:29:39 2009 JenneOmnistructureDMFDMF being whiny again

Quote:
The seisBLRMS has been running on megatron via an open terminal ssh'd into there from allegra with matlab running.


[Yoichi, Jenne]

seisBLRMS was down again. I assumed it was just because the DMF Master Enable was in the 'Disabled' state, but enabling it didn't do the trick. Rana's green terminal window was complaining about not being able to find nodus.ligo.caltech.edu. Yoichi and I stopped it, closed and restarted Matlab, ran mdv_config, then ran seisBLRMS again, and it seems happy now.

On the todo list still is making the DMF / seisBLRMS stuff happy all the time.
  1422   Tue Mar 24 13:54:49 2009 JenneUpdateSUSOp Levs Centered

ITMX, ITMY, BS, SRM, PRM op levs were all recentered.  ETM's looked okay enough to leave as-is. 

  1423   Tue Mar 24 19:55:24 2009 JenneUpdateLSCNew PO DC

[Rana, Jamie, Jenne]

SPOB DC hasn't been so good lately, so we installed a new PO DC PD on the PO table.  We used a 30% reflecting beam splitter (BS1-1064-30-1025-someotherstuff).  We didn't check with a power meter that it's a 30% BS, but it seems like that's about right.  The beamsplitter is as close as we could get to the shutter immediately in front of the regular POB/SPOB PD's, since that's where the beam gets narrow.   The new picked-off-pickoff beam goes to a Thorlabs 100A PD.  We haven't yet checked for reflected beams off the PD,  but there is a spare razor blade beam dump on the table which can be used for this purpose.  The output of this PD goes to the LSC rack via a BNC cable.  (This BNC cable was appropriated from it's previous "use" connecting a photodiode from the AP table to a bit of air just next to the LSC rack.)  Our new cable is now connected where the old SPOB DC cable used to be, at the input of a crazy Pomona Box tee.

For reference, the new levels of POB DC and SPOB DC, as measured by their BNC DC out connections is ~4mV each.  Since the beamsplitter is 70% transmissive, we used to be getting about 5.7mV on each PD.

The new photodiode puts out about 40mV, but it has an ND1.0 filter on, so if more gain is needed, we can take it off to get more volts.

 

  1429   Wed Mar 25 20:41:43 2009 JenneUpdateIOOMode Cleaner Servo Board Transfer Functions (to be updated)

When all things fail (netgpibdata.py is giving me weird data.  When I plot the data it has saved from the 4395A, it's some wierd other universe's version of my transfer function.  I don't really know what's up.  I'm pretty sure I'm getting the 'correct' data, since each TF looks vaguely like it should, but with some crazy humps.  I'll talk to Yoichi in the morning about it maybe.) (also, we're low on emergeny floppy discs), you can always take a picture of the Agilent 4395's screen, as shown below.

* Mode cleaner and PMC are both relocked after my shenanigans, and I'll try again in the morning (I assume locking is going on tonight) to get real TF's with real data, as opposed to the photo method.

Note to self:  post the data of the TFs in the elog along with the plots, for posterity.

 

These TFs are of the Mode Cleaner servo board, exciting IN1 (or the 3.7MHz notch pomona box which is connected to IN1), and measuring at the SERVO out of the board.

One with the box, one without the box, and one of just the box for good measure.

  1430   Thu Mar 26 00:45:24 2009 JenneUpdateIOOMode Cleaner Servo Board Transfer Functions (to be updated)

Quote:

netgpibdata.py is giving me weird data.  When I plot the data it has saved from the 4395A, it's some wierd other universe's version of my transfer function.  I don't really know what's up. 

 Yoichi, in all his infinite wisdom, reminded me that the netgpibdata script saves the data as the REAL and IMAGINARY parts, not the Mag and Phase.  Brilliant.   Using that nugget of information, here are the TFs that I measured earlier:

The last attachment is the .dat and .par files which contain the data and measurement parameters for the 3 TFs in the plots.

  1453   Fri Apr 3 14:52:38 2009 JenneOmnistructurePEMGuralp is finally back!

After many, many "it'll be there in 2 weeks" from the Guralp people, our seismometer is finally back!

I have it plugged into the Guralp breakout box's Channel 1xyz (so I have unplugged the other Guralp).  Both of the Guralp's are currently sitting under the MC1/MC3 chamber.

Before we can have both Guralps up and running, I need to stuff the next 3 channels of the breakout box (back in the fall, I only had Caryn do 1x, 1y, 1z, and now I need 2x, 2y and 2z done with the fancy low-noise resistors), so all the gains match between the 2 sets of channels.

I'm leaving the new Guralp plugged in so we can see how it behaves for the next couple days, until I take out the breakout box for stuffing.

  1455   Mon Apr 6 19:09:15 2009 JenneUpdatePEMOld Guralp is hooked back up to the ADC

Old Guralp is hooked back up, the new one is sitting next to it, disconnected for now.

  1470   Fri Apr 10 18:11:18 2009 JenneUpdatePSLISS has a bad cable?

[Rob, Jenne]

I noticed that the ISS Mean Value and CS Saturation were both RED and unhappy. (The alarms were going off, and they were both red on the MEDM screen).  None of the MEDM settings seemed off kilter, so we went out to take a look at the PSL table. 

Rob checked that light is indeed going to both of the ISS photodiodes (Morag and Siobhan).  Next we checked that all the cables were good, and that the power to the ISS box was plugged in. In this process, Rob wiggled all the cables to check that they were plugged in.  Just after doing this, the Mean Value and CS Sat were happy again.  Rob thinks the current shunt connection might be bad, but we don't really know which one it was since all of the cables were jiggled between our checking the screens. 

Right now, everything is happy again, but as with all bad-cabling-problems, we'll probably see this one again.

 

 

I don't know why in particular the connection decided to spaz out this afternoon...I don't think anyone opened the PSL table before Rob and I went to investigate.  I was working on the PMC servo (checking the LO levels...to be posted in a couple minutes), but didn't have anything to do with the ISS. After I was done, I put everything back, and locked the PMC and the MC, and everything was good, until some time later when the ISS started flipping out.

  1471   Fri Apr 10 19:09:48 2009 JenneUpdatePSLPMC LO Calibration
I measured the RF LO output level from the PMC's LO board which goes directly into the LO input on the PMC Servo board. This goes hand-in-hand with Rana's thoughts
that we might be giving the PMC mixer a too-low LO value, and we might need to switch out the mixer. Steve ordered some new mixers today to try out.

The RF Output Adjust slider (on the C1:PSL_PMC_PS screen) goes from 0-10V; The nominal value (or at least the value I found it at today) is 2.014V.

To measure the RF level: I unlocked the Mode Cleaner and turned off the ISS servo per Yoichi's suggestion. I then unplugged the input to the PMC servo board's LO input,
and put that cable into a 300MHz 'scope, with 12dB attenuation. The 'scope was AC coupled, with the input set to 50Ohms.

I then changed the RF Output Adjust slider in increments of 0.5, and measured the peak-to-peak values on the scope. In the table and on the plots, I've taken into account
the 12dB attenuation. i.e I actually measured 964mV, so 964mV*10^.6 = 3838mV.


RF Output AdjustOutput measured on scopeOscillator Output Monitor
[V]
[Vpp]
[no units given on MEDM screen]
All \pm 0.0159 all of this column is NEGATIVE
0.00003.8380.007
0.50003.8540.007
1.00003.8380.006
1.50003.8380.007
2.00003.8380.006
2.50003.8380.007
3.00003.8380.007
3.50003.8380.007
4.00003.8380.007
4.50003.8220.007
5.00003.8220.012
5.50003.7900.076
6.00003.7580.257
6.50003.6940.555
7.00003.6150.931
7.50003.5351.277
8.00003.4561.532
8.50003.3921.709
9.00003.3441.829
9.50003.3121.908
10.00003.2961.966


I think it's kind of funky that it's so flat for ~half the slider. Also, the third column includes the Oscillator Output Monitor value from the MEDM screen at various RF Adjust slider values. All of these should be negative (i.e. -0.007), but the TABLE function doesn't like "-" signs. I don't know if this information is degenerate with the 'scope measurements, or if it's an indicator of what (might be) wrong.

After finishing, I plugged the cable back into the PMC servo board as it was, turned back on the ISS and relocked the PMC and the MC.
  1472   Fri Apr 10 19:10:53 2009 JenneUpdateGeneralXarm locked?

I don't know who left the X arm locked, but I just ran the Align Full IFO script, so everything is good in case Yoichi/someone comes in to lock the IFO this weekend.

  1478   Mon Apr 13 17:55:37 2009 JenneUpdatePSLPMC LO Mon Calibration

I have calibrated the PMC LO Mon (C1:PSL-PMC_LODET) on the PMC's EPICS screen, by inputting different RF LO levels into the LO input of the PMC servo board.

 

Since the RF output adjust slider on the PMC's Phase Shifter screen doesn't do a whole lot (see elog 1471), I used a combination of attenuators and the slider to achieve different LO levels. I measured the level of the attenuated RF out of the LO board using the 4395A in spectrum analyzer mode, with the units in dBm, with 50dB attenuation to make it stop complaining about being overloaded.  For each row in the table I measured the RF level using the 4395, then plugged the cable back into the PMC servo board to get the EPICS screen's reading.

The last 2 columns of the table below are the 'settings' I used to get the given RF LO level. 

RF LO Input to PMC Servo Board [dBm] LO Mon on EPICS Screen [no units] RF Output Adjust Slider [V] Attenuators used [dB]
16.004 +- 0.008 0.1200 +- 0.0003 0 0
15.001 +- 0.004 0.0708 +- 0.0008 0 1
14.079 +- 0.008 0.0318 +- 0.0001 8 1
13.002 +- 0.006 0.0126 +- 0.0004 0 3
11.992 +- 0.010 0.0024 +- 0.0008 0 4
10.994 +- 0.010 -0.0024 +- 0.0003 0 4+1=5
9.993 +- 0.008 -0.0047 +- 0.0007 0 3+3=6

 

When the new mixers that Steve ordered come in (tomorrow hopefully), I'll put in a Level 13 mixer in place of the current Level 23 mixer that we have.  Also, Rana suggested increasing the gain on the op-amp which is read out as the LO Mon so that 13dBm looks like 1V.  To do this, it looks like I'll need to increase the gain by ~80.  

  1487   Wed Apr 15 17:11:37 2009 JenneUpdatePSLEdited c1psl.db to calibrate PMC's LO mon


Following the method in Peter's Elog, 

I edited c1psl.db to include the following: 


grecord(calc, "C1:PSL-PMC_LOCALC")
{
        field(INPB,"C1:PSL-PMC_LODET")
        field(SCAN,".1 second")
        field(PREC,"4")
        field(CALC,".955*LOGE(B)-17.11")
}

 

I restarted c1psl (had to go hit the physical reset button since it didn't come back after telnet-ing and "reboot"ing) to make this take effect.

Next step is to tell the PMC screen to look at this _LOCALC rather than _LODET, and the screen will be calibrated into dBm. 

Right now, the screen is as it always has been, because after relooking at the calibration, I no longer believe it.  This calibration claimes -19dBm for an LOmon value of 0.1200, when I actually measured +16dBm for this LOmon value.  So I've screwed something up in doing my MatLAB calibration.  I'll fix it tomorrow, and put in the correct calibration before I change the PMC screen.

 

RefCav, PMC, MC are all back and locked after my shenanigans. 

  1488   Thu Apr 16 11:17:56 2009 JenneUpdatePSLEdited c1psl.db to calibrate PMC's LO mon

Quote:

I edited c1psl.db to include the following: 


grecord(calc, "C1:PSL-PMC_LOCALC")
{
        field(INPB,"C1:PSL-PMC_LODET")
        field(SCAN,".1 second")
        field(PREC,"4")
        field(CALC,".955*LOGE(B)-17.11")
}

 

 As it turns out, I apparently can't tell X from Y when fitting a function in a rush.  The real calibration stuff which is now in c1psl.db is:

 

 

grecord(calc, "C1:PSL-PMC_LOCALC")
{
        field(INPB,"C1:PSL-PMC_LODET")
        field(SCAN,".1 second")
        field(PREC,"4")
        field(CALC,"1.004*LOGE(B)+17.76")
}

I restarted c1psl (again, had to go hit the physical reset button since it didn't come back after a telnet-reboot) to have it take in the changes.  The psl.db file that was in place before yesterday (before I touched it) is saved as psl.db.15Apr2009 just in case.

I edited the PMC EPICS screen to have the LO mon look at C1:PSL-PMC_LOCALC, which is the calibrated channel in dBm.  I also stuck a little label on the screen saying what units it's in, because everyone likes to know what units they're looking at.
  1502   Mon Apr 20 19:51:51 2009 JenneConfigurationPSLPMC has new Level 13 Mixer installed

The new Level 13 mixer on the PMC servo board is installed (minicircuits SRA-3MH).   Since the RF output of the LO board was ~16dBm, I put a 3dB attenuator between the LO board and the LO input on the servo board.  Since the previous cable was *just* the right length, this required adding a tiny bit of cable.  I found a very short cable, which worked out nicely, and didin't leave bunches of extra cable between the two boards.  One of these days if I have time (i.e. if it is necessary), I'll make a new cable for this purpose, so that we don't have 2 cables daisy-chained. 

A note on the Mixer-replacement:  The mixer on the PMC servo board is soldered in a set of 8 through-holes, not stuck in a socket.  So I had to desolder the old Level 23 Mixer (minicircuits RAY-3) which was a total pain.  Unfortunately, in this process, I lifted one of the pads off the back side of the board.  Once the old mixer was removed, it became clear that the pin for the pad I had lifted was shorted via a trace on the front side of the board to the pin directly across from it.  So when installing the new mixer, I did my best to get some solder into the through-hole for the lifted-pad-pin, and then tied it using a jumper wire to the pin that it's shorted to on the front of the board.  You can't see the trace that shorts the two pins because it's underneath the mixer, when the mixer is installed.  (Sidenote: after talking with Rana, this should be okie-dokie, especially if these are ground pins).

The PMC and MC locked nice and happily after I replaced the board and turned all the HV supplies back on, so I call this a success!

I also measured the OLG of the PMC servo after today's adventures in mixer-land.  I get a UGF of 1.4kHz, with 66 degrees of phase margin.  The method for this is in elog 924.

I checked the phase slider setting of the PMC phase screen by putting 30kHz at 100mV into the Ext DC input of the servo board, and looking at the 30kHz peak output of the Mixer Out.  I fiddled with the phase slider, and chose the value for which the 30kHz peak was maximized.  The phase slider is now set to 5.0V. 

  1566   Fri May 8 16:03:31 2009 JenneUpdatePEMUpdate on Jenne's Filtering Stuff

To include the plots that I've been working on in some form other than on my computer, here they are:

First is the big surface plot of all the amplitude spectra, taken in 10min intervals on one month of S5 data. The times when the IFO is unlocked are represented by vertical black stripes (white was way too distracting).  For the paper, I need to recreate this plot, with traces only at selected times (once or twice a week) so that it's not so overwhelmingly large.  But it's pretty cool to look at as-is.

Second is the same information, encoded in a pseudo-BLRMS.  (Pseudo on the RMS part - I don't ever actually take the RMS of the spectra, although perhaps I should).  I've split the data from the surface plot into bands (The same set of bands that we use for the DMF stuff, since those seem like reasonable seismic bands), and integrated under the spectra for each band, at each time.  i.e. one power spectra gives me 5 data points for the BLRMS - one in each band.  This lets us see how good the filter is doing at different times.

At the lower frequencies, after ~25 days, the floor starts to pick up.  So perhaps that's about the end of how long we can use a given Wiener filter for.  Maybe we have to recalculate them about every 3 weeks.  That wouldn't be tragic. 

I don't really know what the crazy big peak in the 0.1-0.3Hz plot is (it's the big yellow blob in the surface plot).  It is there for ~2 days, and it seems awfully symmetric about it's local peak.  I have not yet correlated my peaks to high-seismic times in the H1 elog.  Clearly that's on the immediate todo list. 

Also perhaps on the todo list is to indicate in some way (analagous to the black stripes in the surface plot) times when the data in the band-limited plot is just extrapolated, connecting the dots between 2 valid data points.

 

A few other thoughts:  The time chosen for the training of the filter for these plots is 6:40pm-7:40pm PDT on Sept 9, 2007 (which was a Sunday night).  I need to try training the filter on a more seismically-active time, to see if that helps reduce the diurnal oscillations at high frequency.  If that doesn't do it, then perhaps having a "weekday filter" and an "offpeak" filter would be a good idea.  I'll have to investigate.

  1569   Sat May 9 02:20:11 2009 JenneUpdatePSLLaser head temperature oscillation

Quote:
After the laser cooling pipe was unclogged, the laser head temperature has been oscillating in 24h period.
The laser power shows the same oscillation.
Moreover, there is a trend that the temperature is slowly creeping up.
We have to do something to stop this.
Or Rob has to finish his measurements before the laser dies.


How's DTEC doing? I thought DTEC was kind of in charge of dealing with these kinds of things, but after our laser-cooling-"fixing", DTEC has been railed at 0, aka no range.

After glancing at DTEC with Dataviewer along with HTEMP and AMPMON (my internet is too slow to want to post the pic while ssh-ed into nodus), it looks like DTEC is oscillating along with HTEMP in terms of frequency, but perhaps DTEC is running out of range because it is so close to zero? Maybe?
  1606   Tue May 19 15:54:29 2009 JenneUpdatePEMMore Plots for the S5 H1:DARM Wiener Filtering....

Even more plots for the Wiener filtering!

We have a set of spectrograms, which show (in color) the amplitude spectrum, at various times during a one month stretch of time, during S5. Each vertical data-'stripe' is 10min long.

We also have a set of band-limited plots, which take the spectra at each time, and integrate under it, for different frequency bands.

Each set of plots has the following 3 plots:  The raw DARM spectrum, a ratio of residual/raw, and the residuals, normalized to the first one (on which the wiener filter was trained).

The residuals are the DARM spectrum, after subtracting the Wiener-filtered seismometer witness data.

 

From the ratio plots, it looks like the wiener filter is pretty much equally effective at the time on which the filter was trained, as one month later.  Static filters may be okey-dokey for a long period of time with for the seismic stuff.

  1662   Tue Jun 9 11:29:07 2009 JenneUpdateoplevsMeasured ETMY oplev beam size...put everything back

I measured the ETMY oplev beam size at a couple different distances away from the HeNe by taking out the steering mirror and letting the light propagate a ways.  I put the steering mirror back, aligned the oplev, and was able to relock the Yarm, so I think it's all back as it has been the last couple of weeks.

 

Now I need t o do some geometry and ray-tracing matrices to decide what focal length lens to buy, then we'll have  a shiny new ETMY oplev. 

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