[Jenne, Jamie]

ETMY is now in its new nominal position, according to the rails that Kiwamu put in the other day.  OSEM voltages are all centered, and the magnets looked pretty well centered in the OSEM bores.  We're taking data for some free swinging spectra, to check the decoupling. 

Next up: Align Y-green to the arm, then move on to fixing the other optics that Jamie pointed out.

Below is the overview of all the core IFO suspension input diagonalizatidons.

Summary: ITMY, PRM, BS are really bad (in that order) and are our top priorities.

UPDATE:

I had originally put the condition number of the calculated input matrix (M) in the last column.  However, after some discussion we decided that this is not in fact what we want to look at.  The condition number of a matrix is unity if the matrix is completely diagonal.  However, even our ideal input matrix is not diagonal, so the "best" condition number for the input matrix is unclear.

What instead we do know is that the matrix, B, that describes the difference between the calculated input matrix, M, and the ideal input matrix, M₀: should be diagonal (identity, in fact):

M = M₀ B

B should be diagonal (identity, in fact), and it's condition number should ideally be 1.  So now we calculate B^-1, since it can be calculated from the pre-inverted input matrix:

B^-1 = M^-1 * M₀

From that we calculate cond(B) == cond(B^-1).

cond(B) is our new measure of the "badness" of the OSEMS.

new summary: ITMY, PRM, BS are really bad (in that order) and are our top priorities.

TM		INPUT MATRIX (M)	cond(M)	cond(B)
PRM		pit     yaw     pos     side    butt UL   -2.000  -2.000  -2.000  -0.345   2.097  UR   -0.375  -0.227  -0.312  -0.060   0.247  LR    1.060   1.075   0.971   0.143  -0.984  LL   -0.565  -0.698  -0.717  -0.141   0.672  SD    1.513   1.485   1.498   1.000  -1.590	75.569	106.756
SRM		pit     yaw     pos     side    butt UL    0.791   1.060   1.114  -0.133   1.026  UR    1.022  -0.940   1.052  -0.061  -1.027  LR   -0.978  -0.987   0.886  -0.031   0.903  LL   -1.209   1.013   0.948  -0.103  -1.043  SD    0.286   0.105   1.249   1.000   0.030	2.6501	3.90776
BS		pit     yaw     pos     side    butt UL    1.420   0.818  -0.069   0.352   1.038  UR    0.276  -1.182   1.931  -0.217  -0.905  LR   -1.724  -0.274   1.940  -0.254   0.862  LL   -0.580   1.726  -0.060   0.315  -1.194  SD    0.560   0.171  -3.535   1.000   0.075	9.8152	7.28516
ITMX		pit     yaw     pos     side    butt UL    0.437   1.015   1.050  -0.065   0.714  UR    0.827  -0.985   1.129  -0.221  -0.957  LR   -1.173  -1.205   0.950  -0.281   1.245  LL   -1.563   0.795   0.871  -0.125  -1.084  SD   -0.581  -0.851   2.573   1.000  -0.171	4.08172	4.69811
ITMY		pit     yaw     pos     side    butt UL    0.905  -0.884  -0.873   0.197   0.891  UR   -1.095   1.088   1.127  -0.252  -1.115  LR   -0.012  -0.028   0.002   0.001   0.030  LL    1.988  -2.000  -1.998   0.451   1.964  SD    4.542  -4.608  -4.621   1.000   4.517	801.453	774.901
ETMX		pit     yaw     pos     side    butt UL    0.344   0.475   1.601   0.314   1.043  UR    0.283  -1.525   1.786  -0.071  -1.181  LR   -1.717  -1.569   0.399  -0.102   0.938  LL   -1.656   0.431   0.214   0.283  -0.837  SD    0.995  -2.632  -0.999   1.000  -0.110	4.26181	4.33518
ETMY		pit     yaw     pos     side    butt UL   -0.212   1.272   1.401  -0.127   0.941  UR    0.835  -0.728   1.534  -0.101  -1.054  LR   -0.953  -1.183   0.599  -0.066   0.827  LL   -2.000   0.817   0.466  -0.092  -1.177  SD   -0.172   0.438   2.238   1.000  -0.008	4.04847	4.33725

Jenne told us that the ADC was +/- 2V for 16 bits so our calibration is wrong. Since, the ADC is +/- 10V for 16 bits we need to change our calibration and now we can also use the purple STS breakout box.

I'm pretty sure that don't have any ADC's with this gain. It should be +/- 10V for 16 bits. 

I modified a set of the automated MC locking scripts which are dedicated for the low power MC.

Currently there are three scripts like the usual MC locking scripts:

(1)mcup_low_power, (2) mcdown_low_power and (3) autolockMCmain40_low_power.

I ran those scripts on op340m as usual and so far they are running very well. The lock acquisition is quite repeatable.

I hope theses scripts always bring the lock condition to the same one and hence the LOCKIN signals don't change by every lock.

- To run the script

  log into op340m and run autolockMCmain40m_low_power

ADC: 2¹⁶counts = 4V Hence, calibration of ADC is 2¹⁴counts/V.

Gain of the AA board, g1 = 0.1

GURALP

Sensitivity = 800 V/ms^-1

2¹⁴ counts/V x 800  V/ms^-1 = 13107200 counts/ms^-1 -----> 7.6294e-08 ms^-1/count

Gain, g2 = 10

Calibration = 7.6294e-08 ms^-1/count x g1 x g2 = 7.6294e-08 ms^-1/count

 STS

Sensitivity = 1500 V/ms^-1

2¹⁴ counts/V x 1500  V/ms^-1 = 24576000 counts/ms^-1 -----> 4.069e-08 ms^-1/count

Gain of the STS electronic breakout box, g3 = 10

Calibration = 4.069e-08 ms^-1/count x g1 x g3 = 4.069e-08 ms^-1/count

We turned off the power of the seismometers and moved the Guralp1 close to the STS. Both are now situated below the center of the mode cleaner vacuum tube.

We oriented the X axis of the STS & Guralp1 along the X axis of the interferometer. Then we turned on the power again, but the STS channels don't give any signal. We think this is, because we didn't push the auto zero button.

We got the results of the wiener filtering simulations (Elog Entry)

We got the power spectra and coherence of the seismic noise measurements from GURALPs and STS seismometers (Elog Entry)

We tried to whiten the target and the input signal for the computation of the wiener filter for the real data, but the results are unsatisfactory. We should not care about high frequencies in wiener filter computation so we will just filter them off in the filter output with a low pass filter.

We just found the right gain for the system seismometer-AAboard-ADC (Elog Entry)

Last night, I attached a metal plate to the Vout faceplate of my photosensor circuit box because the BNC connection terminals were loose. This was Jamie's suggestion to establish a more secure connection (I had originally drilled holes for the BNCs that were much too large).

I have also fixed the mechancial set-up of my shaking experiment so that the horizontal sliding platform does not interfere with the photodiode mounting stage. Koji pointed out last night that in the full range of motion, the photodiode mounting stage interferes with the movement of the sliding platform when the platform is at its full range.

I have began shaking. I am getting a problem, as my voltage outputs are just appearing a high-frequency noise.

We used a function generator, an oscilloscope and the Data Viewer to check the gain of the new AA board (used for the seismometers). Putting a sine wave of 0.3V (using a function generator) to the AA board, we could see about 500 counts in the Data Viewer. The calibration of the ADC is 2¹⁴ counts/volt, so the AA board gives to the ADC an output of 0.03V. This proves that the AA board has a gain of 0.1. Guralp1 and STS1 (Bacardi), both have a gain of 10 now, that balance the AAboard gain of 0.1. If we consider the gain of AA board in our calibrated power spectrum plot of seismic signals from Guralp1 and STS1 (Bacardi), we get the following plot:

[Kiwamu, Suresh]

We attempted to minimise the A2L coupling in the MC mirrors (centering the beam spot on the actuation node on each optic).  While it was easy to minimise the coupling in the pitch for all the three optics and yaw of MC2, the yaw alignment of MC1 and MC3 proved to be difficult.  For one the adjustment required was quite large, so much so that PSL alignment into the MC is often lost during this adujstment.  We had to align the PSL coupling several times in order to proceed.   And the MC settles into a new position when the MC-PSL servo loop was disturbed by random denizens in the lab.  Requiring us to start over again.

Kiwamu wrote a script to measure the MC(optic)(Pitch/yaw) -> Lockin(#1 to #6) matrix.  Inverting this matrix gave us the linear combination of the offsets to put on the MC# PIT/YAW  inorder to minimise a specific Lockin output.  However the cross couplings were not completely eliminated.  This made it very hard to predict what a given set of offsets were going to do to the Lockin outputs.

Net result:  the spots are centered in vertical direction (pitch) but not in the horizontal (yaw)

Day time tasks have started so I am quitting now.

I've finished using the network analyzer to characterize find a dither frequency for driving the PZT to use in my PDH locking. I found a region in which the amplitude response of the PZT is low: The dip is centered at 2.418 MHz. Changing the NPRO laser temperature by 100mK has no significant effect on the transfer function in that region. I will post plots tomorrow.

I'm finished with the network analyzer. It is unplugged, and the cart is still near the PSL table. (I'll roll it back tomorrow when it won't disturb interferometer locking).

I closed the shutter on the NPRO at the end of the night.

Tomorrow I plan to put together the fast locking setup. I'll drive the PZT at 2.418 MHz. More details to come tomorrow.

 02:27am, ran the new freeswinging-ifo.csh script.  It's just a copy of freeswinging-all.csh, but it doesn't include the MC mirrors, since Suresh and Kiwamu are still working.  

Now we have copies of the script for -all, -mc, -ifo to cover the various sections of the suspended interferometer.

[Rana Koji Jenne Jamie]

- The situation of the ETMY suspension is improved.
- The damping servos except for Pitch are now functional.
- We intentionally turned off the damping servos for the matrix measurements.

- Opened the light door of the ETMY chamber.

- We set up the CDS SUS lockin:

        Excite UL/UR/LL/LR equally [by setting the output matrix (1, 1, 1, 1, 0)] at 3.12Hz with 2000 cnts
        Put the OSEM PD outputs into lockin one by one. For the image rejection, 0.1Hz 4th order LPF has been used though we like to use a faster settling LPF.

- Found only UL was responding to the excitation. After fitzing with the cables and connectors, it was found that the DAC card was loose from the bus.
  By pushing the card the responses have been back. [Note we had the reboot of c1iscey almost at the same time.]

- Checked the response in the I channel of the lockin.
        UL -8ish / UR +7ish / LR +5ish / LL +2ish

- Tweaked LL sensor to get better response ==> in vain. Decided to move the lower OSEM plate for the better positioning of the LR/LL.
- Got reasonable (+5ish) response for LL.

- Confirmed that the POS/YAW/SIDE damping works with positive gains. PITCH did not work with the negative gain (but that could be a good sign.)

- Let the suspension freely swinging for a while (~30min). Checked the side/pos separation. They are not perfect but seemed diagonalizable.

- Closed the light door.

- Jenne will make a better kick/free-swing test later.

I updated the peakFit routines to make them a bit more user friendly:

• modified so that any subset of optics can be processed at a time, instead of just all
• broke out tweakable fit parameters into a separate parameters.m file
• added a README that describes use

These changes were committed to the 40m svn.

Suresh and I tweaked the OSEM angles in ETMX yesterday.  Last night the ETMs were left free swinging, and today I ran Rana's peakFit scripts on ETMX to check the input diagnolization:

It's well inverted, but the matrix elements are not great:

       pit       yaw       pos       side      butt
UL    0.3466    0.4685    1.6092    0.3107    1.0428
UR    0.2630   -1.5315    1.7894   -0.0706   -1.1859
LR   -1.7370   -1.5681    0.3908   -0.0964    0.9392
LL   -1.6534    0.4319    0.2106    0.2849   -0.8320
SD    1.0834   -2.6676   -0.9920    1.0000   -0.1101

The magnets are all pretty well centered in the OSEMS, and we worked at rotating the OSEMS such that the bounce mode was minimized.

Rana and Koji are working on ETMY now.  Maybe they'll come up with a better procedure.

This week, I have finished assembling everything I need to begin shaking. I built an intermediary mounting stage to mount the TT suspension base to the horizontal sliding platform, finished assembling the second photodiode, finished assembling the photosensor circuit box, and calibrated the two photosensors. Today I built a platform/stage to mount the photodiodes so that they are located close enough to the mirror/suspension that they can operate in the linear range.  Below is an image of the set-up.

The amplifer that Koji fixed is acting a bit strange again...It is sometimes shutting off (Apparently, it can only manage to do short runs ~ 1minute? That should be enough time?).

The set-up is ready to begin taking measurements.

Jenne found a big scratch on the north vac door of ITMY. Fortunately it does not reach the inner annulos 0 -ring seal.

This is precisely what we have to avoid to preserve our vacuum system!

I measured the particles coming off of new- unused clean room coat. Tyvek, Convertors, Allegiance #9393 measured  10 counts of 0.3 micron at 1 minute and 0 count at 7 minute.

The 0.5 micron size  measured 0 at both times. Jenne's used coat measured 20 counts of 0.3 micron  and 0 counts for 0.5 micron at 1 minute. ( counts / cf- min)

The HEPA tent background is consistently 0 when it's CP STAT 100 curtains are closed.

We did the simulation of the stacks by defining a transfer function for one stack (green plot) and another similar transfer function for the other stack.

We simulated the ground motion by filtering a white noise with a low pass filter with a cutoff frequency at 10Hz. (blue plot) (the ground motion for the 2 stacks are completely uncorrelated)

We simulated the electronic white noise for the seismic measurements. (black plot)

We filtered the ground motion (without the measurements electronic noise) with the stack's transfer function and subtracted them to find the mirror response (red plot), which is the target signal for the wiener filter.

We computed the static wiener filter with the target signal (distance between the mirrors) and the input data (seismic measurements = ground motion + electronic noise).

We filtered the input and plotted the output (light blue plot).

We subtracted the target and the output to find the residual (magenta plot).

We didn't figure out why the residual is above the electronic noise only under ~6hz. We tried to increase and decrease the electronic noise and the residual follows the noise still only under ~6Hz.

It also shows that the residues are above the target at frequencies over 20Hz. This means that we are injecting noise here.

We tried to whiten the target and the input (using an high pass filter) to make the wiener filter to care even of higher frequencies.

The residues are more omogeneously following the target.

We also plotted the Wiener filter transfer function without making whitening and with making whitening. It shows that if we do whitening we inject no noise at high frequency. But we loose efficency at low frequencies.

We shouldn't care about high frequency, because the seismometers response is not good over 50Hz. So, instead of whitening, we should simply apply a low pass filter to the filter output to do not inject noise and keep a good reduction at low frequencies.

The top plot shows a sweep from 10 kHz to 5 MHz of the ratio of the voltage output of the PD detecting power from the NPRO laser beam and the RF source voltage (the magnitude of the complex transfer function). The black trace was taken with the laser beam blocked. For runs 2 and 3 I changed the laser temperature set point by 10 mK and 100 mK respectively to see if there was a significant change in the AM response. The bottom plots shows runs 2 and 3 compared to run 1 plotted in dB (to be explicit, i'm plotting 10 times the base 10 log of the magnitude of the ratio of two complex transfer functions). Changing the temperature seems to have only a minor effect on the output except at around 450kHz, where the response has a large peak in run 1 and much smaller peaks in runs 2 and 3. 

The traces in the top plot consist of 16 averages taken with a 300Hz IF bandwidth, 15 dBm source power (attenuated with a 6 dB attenuator) and with 20dB attenuation of the input power from the PD.

Next I'm going to probe a narrow band region where the response is low (2.0MHz or 2.4MHz perhaps) and choose a bandwidth for the dither frequency for the PDH locking.

This morning Kiwamu and I have aligned the MC. Kiwamu aligned the last steering (on the OMC table) to recover the touch last week.
Then I have aligned the MC with MC1 and MC3 as the last steering did not help to get TEM00.

Before

C1:SUS-MC1_PIT_COMM = 2.6587
C1:SUS-MC1_YAW_COMM = 2.7471
C1:SUS-MC2_PIT_COMM = 3.486
C1:SUS-MC2_YAW_COMM = -1.1592
C1:SUS-MC3_PIT_COMM = -1.876
C1:SUS-MC3_YAW_COMM = 1.2829

After

C1:SUS-MC1_PIT_COMM = 2.7596
C1:SUS-MC1_YAW_COMM = 2.6627
C1:SUS-MC2_PIT_COMM = 3.486
C1:SUS-MC2_YAW_COMM = -1.1592
C1:SUS-MC3_PIT_COMM = -1.697
C1:SUS-MC3_YAW_COMM = 1.2901

Here are the new calibration plots for my photosensors. These calibrations were done using a translation stage.

The linear region for the first photosensor appears to be between 15.2mm and 30 mm

The linear region for the second photosensor appears to be between 12.7mm and 22.9mm

The slope for both is -0.32 V/mm  (more precisely, -0.3201 V/mm for PS 1 and -0.3195 V/mm for PS 2)

I believe that the 17 Hz broad structure on SIDE is just because of a bad rotational angle of the SIDE OSEM.

The same structure had been observed on the EMTY_UR, and the structure became narrower after we repositioned/rotated the OSEM yesterday.

My guess is that the SIDE OSEM is now in a place where the OSEM is quite sensitive to the bounce mode

and creating the broad structure due to a bi-linear coupling between the bounce mode and low frequency signals.

We will move on to the vertex region today.

The goal of the vertex region work is to get the pick-off beams out the chambers, including POX/Y and POP.

The work will be in parallel to the ETM woks.

The first step will be : lock and align MC with the IR beam.

Summary of the week ending Aug 8th.  Number of elog entries = 56

- VAC
 + The vent started Wednesday morning
 + Repositioning of the green periscopes and associated mirrors are done.
 + Got both of the green beams coming out from  the chambers
 + Moved the ETMX suspension tower by -8.09 inch (away from vertex)
 + Fixed the alignment of the ETMX CCD mirrors
 + Recovered the X green beam axis for the latest ETMX position

- SUS
 + oplev centered prior to the vent

- LSC
 + ETMY_TRANS_QPD didn't respond at all, needs to be fixed
 + Old MZ PD (InGaAs 2mm, @29.5MHz) has been modified for REFL33.
  The 11MHz notch circuit is at the amp side instead of the diode side. This is ready for the installation
 + REFL165 PD has been made from the old 166MHz PD.

- IOO
 + IPPOS has been sick since 19th of July, 2011
 + IPANG is clipped on a pick-up mirror on the ETMY table. QPD itself is healthy.
 + The spot positions on the MC mirrors were measured prior to the vent.
   The results are almost the same as before within a few percent difference expect for the MC2 yaw.
 + An attenuator, consisting of two HWPs and a PBS, has been installed on the PSL table for the MC low power state.
 + a 10% BS in front of the MCREFL_RFPD was replaced by a perfect reflector for the low power mode.
 + The incident power for MC was decreased to 20 mW
 + The beam axis going to MC was misalgned due to the attenutor.
    Then the beam was aligned by touching two steering mirrors on the PSL table
 + MC is able to be locked in air. The reflection DC goes from 1.4 to 0.13 V when the MC is locked.

- ABSL
 + With the mass-kicking technique, the arm lengths were measured.
   Xarm =  37.5918 m, Yarm = 37.5425 m.

- Green locking
 + Y green beam is aligned to the Y arm
 + Locking of the Y green is not robust, it needs to be revisited

- OAF
 + Wiener Filtering was applied on the data collected from the X-arm for a duration of 1500 seconds.

- Misc.
 + The hazardous waste people are moving chemicals around outside our door, and have roped off our regular front door.
 + The horizontal trolley drive of the east end crane stopped working. It will be fixed.

I switched off damping to the ETMX and used a reduced version of freeswing-all.csh script (called freeswing-ETMX.csh) to set it swinging.    After about an hour I used the saved template ETMX/2008.08.06.xml to obtain the following plot.

There is something defintely wrong with the side sensor.  It might be the electronics as it also has this problem with it slow channel readings (my previous elog today).

Using a PDA255 on the PSL table, I measured the amplitude response of the NPRO PZT, sweeping from 10kHz to 5 MHz.

I took a run with the laser beam blocked. I then took three runs with the beam unblocked, changing the temperature of the laser by 10 mK between the first two runs and by 100mK between the second and third runs.

At the end of the night I turned off the network analyzer and unplugged the inputs. I'm leaving it near the PSL table, because I'd like to take more measurements tomorrow, probing a narrow bandwidth where the amplitude response is low.

On the PSL table, I'm still monitoring the reflected light from the cavity and the transmitted light through the cavity on the oscilloscope. I'm no longer driving the NPRO temperature with the lock-in.

I closed the shutter on the NPRO laser at the end of the night.

I'll log more details on the data tomorrow morning.

We did offline wiener filtering on 3rd August (Elog entry) using only Guralps' channels X and Y.

Here we report the Power spectrum of the 3 seismometers (Guralp1, Guralp2, STS1) during that time.

and also the coherence between the data from different channels of the 3 seismometers.

We see that the STS is less correlated with the two Guralps. We think it is due to the wrong alignment of the STS with the interferometer's axes.

We are going to align the STS and move the seismometers closer to the stacks of the X arm.

[Rana / Jenne / Kiwamu]

The ETMY suspension tower is currently sitting on the north side of the table for some inspections.

The adjustment of the OSEMs is ongoing.

(What we did)

  + Taken out two oplev mirrors, Jamie's windmill and a lemo patch panel.

  + Put some pieces of metal as makers for the original place

  + Put some makers on the distance of  dLY = -25.49 cm = -10.04 inch from the original place (see the 40m wiki).

     The minus sign means it will move away from the vertex.

  + Brought the ETMY suspension tower to the north side to do some inspections

  + Did some inspections by taking the noise spectra (#5141)

  + Adjusted the OSEM range and brought the magnets on the center of the OSEM holders by rotating and translating the OSEMs

  + During the work we found the proper PIT and YAW gains were about -5, which are the opposite sign from what they used to be.

  + Trying to minimize the cross couplings

JD: There is still some funny business going on, like perhaps the LR magnet isn't quite in the OSEM beam.  We leave the optic free swinging, and will continue to investigate in the morning.

The slow signal from the side sensor on ETMX was last seen in action sometime in May 2010!  And then the frame builder has no data for a while on this channel.  After that the channel shows some bistability starting Sept 2010 but has not been working.  The fast channel of this sensor  (C1:SUS-ETMX_SDSEN_OUTPUT) does work so the sensor is working.  Probably is a loose contact... needs to be fixed.

Today I balanced the mirror, finished putting together the second photosensor, and finished my photosensor circuit box! 

Upon Jamie's suggestion, I have used a translation stage to obtain calibration data points (voltage outputs relative to displacement) for the new photosensor and for the first photosensor.

I will plot these tomorrow morning (too hungry now > < )

Here is a photo of the inside of my circuit box! It is finally done! It is now enclosed in a nice aluminum casing ^ ^

 I rolled the network analyzer over to the PSL table (on the south side). I'm borrowing the DC block from Kiwamu's green locking setup. I'm going to first measure the amplitude response of a low pass filter to made sure that the analyzer is outputting what I expect. Then I will measure the laser PZT amplitude response. I plan to finish the measurement and return the network analyzer to it's usual location tonight.

> Also the BS is missing its DAQ channels again (JAMIE !) so we can't diagnose it with the free swinging method.

I'm not sure why the BS channels were not being acquired.  I reran the activateDQ script, which seemed to fix everything.  The BS DQ channels are now there.

I also noticed that for some reason there were SUS-BS-ASC{PIT,YAW}_IN1_DQ channels, even though they had their acquire flags set to 0.  This means that they were showing up like test point channels, but not being written to frames by the frame builder.  This is pretty unusual, so I'm not sure why they were there.  I removed them.

The RGA region is beeing monitored during the vent. This will tell us how clean the RGA itself is.

Since ETMY have been showing some strange behaviors we deeply inspect the ETMY suspension.

Here is a brief review of the ETMY suspension and a brief status update of the inspection so far.

The inspection is still ongoing.

(Review : How wrong ?)

First of all, let us summarize what were the observed phenomena on the ETMY suspension :

   1. unknown low frequency noise covering frequency range from 0.1 to 3 Hz in all of four face sensors (#5025, #5029).

   2. LR sensor showed a very broad bounce peak at ~ 17 Hz (#5025).

   3. The sign of some of the sensors are flipped.

   4. The control gains had to be higher than those of ETMX by 10-100 (#5025).

(Status update : Noise spectra)

Currently the ETMY suspension is sitting on the north side of the table for the inspection.

We took dark noise of the OSEMs when the OSEMs were taken off from the tower and put on the table.

The plot below is an example of the LR sensor spectra. Note that the whitening filters have been always ON.

The black curve is the dark noise when the sensor was off from the tower.

The blue curve is the free swinging spectrum newly taken today.

The red curve is the free swinging spectrum (damped spectrum ?) on 25th of July, this was still in vacuum.

The dark noise is below the free swinging spectrum from 0.2 - 30 Hz, which looks reasonable

The most interesting thing is that the free swinging spectrum became better in low frequency (below 3 Hz)

from the one measured in vacuum.

It needs more investigation to answer the reason why it happened.

Note that before we moved the tower to the current position, we looked at the OSEM-magnets relations, and found nothing was touching.

 The east end particle count is 155K for 0.3 micron and 15K for 0.5 micron  counts/cf min.  In order to minimize diffusion of dirt into the IFO we set up the mobile HEPA with CP Stat 100 tent.

This set up gives us practically ZERO inside the tent

Konecrane Fred was early this morning. He diagnosed the ETMY crane horizontal drive gear box dead and left just before the film crew showed up.

New gear box should be here by the end of this week for installation.

The lab air quality is high ~20,000 counts of particles of 0.5 micron.  Keep an eye on this before you open the chamber.

A plot showing that the daily variation in the OLs is sometimes almost as much as the full scale readout (-1 to +1).

Besides the purpose of correctly tuning the suspensions, my hidden goal in the input matrix diagonalization has been to figure out what the 'true' sensing noise of the OSEMs is so that we can accurately predict the noise impact on the OAF.

The attached plot shows the DOFs of ITMX calibrated into microns or microrad as per Jamie's ethereal input matrix calculations.

The main result is in the ratio of POS to BUTTER. It tells us that even at nighttime (when this data was taken) we should be able to get some reduction in the arms at 1 Hz.

Whether we can get anything down to 0.1 Hz depends on how the arm control signal compares to the POS signal here. I leave it to Jenne to overlay those traces using a recent Arm lock.

I've finally completed the SUS/peakFit/ scripts which find the new input matrix for the SUS. MC1, MC2, MC3, and ITMX have been matrix'd.

I tried to do the BS, but it came out with very funny matrix elements. Also the BS is missing its DAQ channels again (JAMIE !) so we can't diagnose it with the free swinging method.

To continue, we have to get some good data and try this again. Right now there are some weird issues with a lot of the optics. I've also set the damping gains for the optics with the new matrices.

 Ex.

new_matrix = findMatrix('ITMX')

writeSUSinmat('ITMX', new_matrix)

writeSUSinmat.m

this script writes the values to the MEDM input SUS matrix. To do the writing, I used the low level 'caput' command instead of ezcawrite since the ezca libraries are getting deprecated.

caput doesn't really have good diagnostics, so I use matlab to check the return status and then display to the terminal. You can just rerun it if it gives you an error.

A coupled of normalization notes:

1) The POS/PIT/YAW rows are scaled so that the mean of abs(FACE elements) = 1. Previously, I had the max element = 1.

2) The SIDE row is scaled so that the SIDE element = +1.

3) I then normalized the ROWS according to the geometrical factors that Jamie has calculated and almost put into the elog.

All these scripts have been added to the SVN. I've removed the large binary data files from the directory though. You can just rsync them in to your laptop if you want to run this stuff remotely.

 You meant ETMX, right?  ETMY still hasn't been touched.

KI : sorry, I meant ETMX. I fixed the entry.

[Jenne, Kiwamu]

While Kiwamu was finalizing the X green alignment, I started to prepare to remove the ETMY door, and begin checking out its OSEMs, etc, so we could start moving it to it's new place, and figure out why it's been wonky for a while.  I ran the particle counter, and we have a factor of ~5 more particles than normal.  Kiwamu and I agreed not to open ETMY.  Since we had briefly opened the IOO and Output Optics chambers to check the X green's position on the PSL table, we immediately shut those doors.  They were probably open for ~15 minutes or so.  (Yes Steve, we should have checked before opening any doors, but at least we remembered to check at all, and the doors were only open for a few minutes rather than for a few hours.)

I attach a 24hrs trend of the particle counts, for reference.  It looks like it's been a little high for a while, but today it's really dirty in the air.

[Jenne / Kiwamu]

 The X green beam has been realigned to compensate the effect of the ETMX repositioning.

After the alignment we became able to lock the 00 mode with the X green beam.

For the alignment:

  spot position on the ETMX mirror = within ~ 1 cm. This number is strictly constrained by a homemade aluminum iris that Jamie put last Friday.

  spot position on the ITMX mirror = unknown, but looks pretty good on the CCD camera.

  spot position on the PSL table = ~ 1 mm downward from what it used to be. The horizontal alignment is perfect.

Conclusions :

  The X green beam again became a reference of the beam axis.

  The ETMX suspension tower is in a good place.

 Kiwamu suggested that since the side resonance is at a lower frequency than the bounce (~17Hz)  we ought to worry about the side more than the bounce.  If this is okay we can reposition the OSEMs to minimise this coupling. 

More over, in the current position, the OSEM s will not sense the side motion!!  So we definitely need to reposition them.  Sorry! I was being a spatz. 

This OSEM placement is just the OPPOSITE of what the proper placement is.

Usually, we want to put them in so that the LED beam is vertical. This makes the OSEM immune to the optic's vertical mode.

The orientation with the horizontal LED beam makes the immunity to the side mode better, but may spoil the vertical.

In reality, neither of these assumptions is quite right. The LED beam doesn't come out straight. That's why Osamu and I found that we have to put in some custom orientations.

Also, the magnet gluings relative to the OSEM bracket centers are not perfectly aligned. So...I am saying that the OSEMs have to be oriented empirically to reduce the couplings which we want to reduce.

The table below gives the OSEM positions as seen on the slow chanels C1:SUS-ETMX_{UL,UR,LL,LR,SD}PDMon

Note that the side OSEM has the fast channel (OUTPUT) available and we used that to locate it.

When we began work the OSEMs were photographed so that we have a record of their locations till now.  It was difficult to get accurate estimate of the magnet offset inside the OSEM we could not see the screen on the camera while clicking.  We then took some pictures after finishing the work. These are given below

The picture of the left is from before OSEMs were moved. It can be seen that OSEMs are rotated to make sure that the magnets avoid touching the teflon sheets which hold the shadow sensors.  The picture on the right shows the positions of the OSEMs after we adjusted their positions.  This time we kept the teflon sheets vertical as shown to minimise the coupling between the Side and Axial directions.

We needed to reposition them once again after we moved the tower to the center of the table.

Pictures with more detail will be posted to the wiki later.

Also, according to Steve, there will be some crane guys for fixing the Y end crane issue (#5124) Monday morning.

Just a reminder that a film crew will be here Monday morning, filming Christian Ott for some Discovery channel show.

They are slated to be here from 8am to 12:30pm or so.  They will take a couple of shots inside the lab, and the rest of the filming should be of Christian in the control room (which they will "clean up" and fit with "sexy lighting").  I will try to be here the whole time to oversee everything.