Noise below 10 Hz became larger again compared with the data before (see here #4352)

Note that the Y-axis is in MHz.

Ansell AccuTech 91-300 clean room gloves  ONLY in the 40m lab.

Cleaning and preparation must be carried out in these gloves also.

The screens for the simplified c1spx model have been updated.  I re-introduced the suspension point information into the sensor output matrix so we can take into account the fact that as the entire supporting structure moves, the osems moves relative to the optic.

Master screens for the noise filters (i.e. 60 Hz, suspension point motion, and optic noise) have been created.

I have currently set the matrix values of the c1spx model to handle just longitudinal motion.  I.e. Coils drive only in the POS degree of freedom and sensor read outs are also only in the POS degree of freedom.  I've turned off all the noise inputs.

I added a simple double pole at 1 Hz in the C1:SUP_ETMX_PL_F2P_0_0 filter bank.

Here is a diagram for our intensity noise coupling measurement.

The below is a plot for the intensity noise on the DCPD. (I forgot to take a spectra of the PD dark noise)

For some reason, the RIN spectrum becomes sometimes noisier and sometimes quieter. Note that after 10 pm it's been in the quiet state for most of the time.

An interesting thing is that the structure below 3 Hz looks like excited by motion of the MC when it's in the louder state.

[Koji, Steve, Suresh, Kiwamu]

The following video cables have been newly laid down :

  - MC1F/MC3F (65 ft.)

  - PMCR (100 ft.)

  - PSL spare (100 ft.)

  - PSL1  (100 ft.)

  - PSL2  (100 ft.)

We have one single O-ring on the 40m vacuum envelope. It is on the OOC west side, facing the AP table. This O-ring has to be protected from the force of this

door. There should be 3 shims  ~120 degrees apart to carry the full load, so it is not the O-ring that is getting squashed.

This morning I found only one of these shims in place.

Here is a new plot for the differential noise measurement. I plot a noise contribution from the intensity noise (brown curve).

If we believe this data, the differential noise is NOT dominated by the intensity noise of the PSL.

(intensity noise coupling measurement)

 Here is a plot for the transfer functions (TFs) from the intensity noise DCPD to the beat signal.

   In principle these TFs tell us how much intensity noise are contributed into the differential noise.

When I measured the spectra shown above, the frequency offset of the beatnote was at about 8 MHz from the zero cross point.

Keeping the same lock, I measured the transfer function (red curve) by using the swept sine technique on DTT. The setup for this measurement is depicted on the last entry (#4389).

Then I made the spectra above by multiplying the intensity spectrum by this TF.

  Later I measured another transfer function when the beatnote was at about 2 MHz from the zero cross point.

According to this measurement, our MFD gets insensitive to the intensity noise as the beat offset goes close to the zero cross point. This is consistent with what we expected.

For some reason the c1ioo machine suddenly died just 30 miteus before.

It died after we added a DAQ channel for c1gcv and rebooted the frame builder.

It didn't respond to a ping command. Therefore I rebooted the machine by clicking the physical reset button.

Now it seems fine.

Today was a banner day for Simulated Plants.

Joe and Jamie have been working to get it all happening and this afternoon we started stuffing filters into the plant to make it act like the:

We put in the following features so far:

1. Anti-Imaging filters (these are hacked to be approximate since the real ones are 7570 Hz LP filters and the SimAI only can have filters up to 8192 Hz).
2. Dewhitening filters (copied from the SimDW in the SUS-ETMY screens)
3. Coil Driver transimpedance (1 / 200 Ohms)
4. Magnet-coil force constant (0.016 N/A)
5. Conversion from Coil to DOF Basis
6. All DOFs of the mechanical model are represented as simple harmonic oscillators with Q~100 and f ~ measured free swinging peaks.
7. Signals/Noise can be injected either as force noise on the test mass or as displacement noise at the suspension point.
8. Conversion from DOF to Shadow Sensor basis.
9. Optical Levers (with whitening)
10. Shadow Sensors have 2V/mm readout gain and whitening filters before being digitized by the SimADC.

We have also changed the switching logic for the SUS and SimETMs for the shadow sensor whitening. It used to be that either the hardware OR the software whitening was on. Now we have made it like all of the other whitening/antiwhitening in LIGO and the whitening/antiwhitening come on together. Joe and Jamie are going to propagate this to the other SUS. The hardware filter is a 30,100:3 (poles:zeros) whitening filter. The digital filter used to also be 30,100:3 with a DC gain = 1. I've changed the FM1 filter in the XXSEN filter banks into a 3:30 for the ETMY so that it now comes on and just compensates the hardware filter. This change should be propagated to all other SUS and the MEDM screens updated to show the new situation.

After this change, we decided to calibrate the {UL,UR,LL,LR,SD}SEN channels into units of microns. To do this we have made an FM6 filter called 'cts2um' that accounts for the OSEM gain and the ADC conversion factors. These channels are now in units of microns without applying any calibration in the DTT or Dataviewer. The plot below shows the OSEM shadow sensor time series with all damping loops ON and a very rough version of seismic noise being injected in all 6 DOFs (note that the y-axis is microns and the x-axis is seconds).

Next, Jamie is adding the angular calibrations (so that SUSPIT and SUSYAW are in rads) and Chris is making vectift quality seismic noise injectors.

We also need to add coating thermal noise, suspension thermal noise, substrate thermal noise, ADC/DAC noise and a lot of MEDM screen indicators of what state we're in. I myself can't tell from the OSEM time series if its real or Sim.

I measured the transfer function, shot noise, and dark spectrum of AS55.

From the shot noise measurement, the RF transimpedance is (556.3 +- 0.8) Ohms and the dark current is (2.39 +- 0.01) mA. The dark noise agrees with the approximate value calculated from the circuit components.

There are no anomalous oscillations when there is no light on the photodiode. I am working on fitting the transfer function in LISO but the other plots are on the wiki at http://blue.ligo-wa.caltech.edu:8000/40m/Electronics/AS55

To simulate digitization noise, the easiest way I found was to use the MathFunction block, found in the CDS_PARTS model, under simLinkParts. 

The MathFunction block supports square of input value, square root of input value, reciprocal of input value, and modulo of two input values.

The last is useful because it casts the input values as integers before taking the modulo.By placing this block after the saturation block (set to +/- 32768), adding 32768.5, choosing the 2nd input to be larger than 2 * 32768 (100,000 in this case), and then subtracting 32768, we wind up with a rounding function. 

The above method has been applied to the c1spy model in the CI and SO out sub-blocks.

We are limited by the intensity noise of the X arm transmitted green light.

Since the intensity noise from the PSL wasn't big enough to explain the differential noise (#4392), so this time I measured the noise contribution from the X arm transmitted light.

(coupling measurement)

  I performed the same intensity noise coupling measurement, but this time between the DC signal of the beatnote RFPD and the beatnote signal.

 While measuring it, I excited the intensity of the PSL laser by using the same AOM like I did yesterday. This AM cause the observable intensity noise on the beatnote RFPD.

With the excited AM, we can pretend to have an excited AM on the green transmitted light from the X arm, of course assuming the intensity noise coupling from the PSL is less.

The next steps we should do are :

We can modify the freq divider circuit to make it a comparator.

There are 3 standard techniques to reduce this effect:

1) Stabilize the end laser by sensing the green light coming into the PSL before recombination and feeding back with SR560 (this is the only one that you should try at first).

2) Moving to the center of the MFD fringe via ETM steps.

3) Auto-alignment of the beam to the arm.

Aidan: Joe and I have added a channel that takes the DC output from the vertex beatnote PD and sends it, via RFM, to a DAC at the ETMX end. Immediately before the output is a filter C1GCX_AMP_CTRL. The output of the DAC is connected to the CURRENT LASER DIODE modulation input on the back of the Innolight driver. This will modulate the current by 0.1A/V input.

We should be able to modulate the green laser on the end now and stabilize the intensity of the amplitude on the beatnote PD at the vertex. (In this configuration, the ampltiude noise of the PSL laser will be injected onto the end laser - we may want to revisit that).

Joe's comments on model change:

I added a RFM connection at the output of the C1:GCV-XARM_BEAT_DC filter in the c1gcv model.  The RFM connection is called: C1:GCV-SCX_ETMX_AMP_CTRL.

This RFM connection goes to the c1scx model and into Kiwamu's GCX box, which uses top_names.  There's a filter inside called AMP_CTRL, so the full filter name is C1:GCX-AMP_CTRL.  The output then goes to the 7th DAC output.

Photos:

1. NPRO CURRENT CTRL plugged into DAC channel 7
2. You can actually see it's channel 7 in this image
3. The other end plugged into the back of the Innolight driver
4. Schematic of the setup
5. Updated C1ALS_OVERVIEW MEDM screen (I don't know why the field in the background turned orange - maybe it's coming into a long dry summer?)

The reason that I chose this PD is that, apparently, the green light coming from the cavity is clipped when it is picked off for its DC PD.

[Kiwamu, Larisa] 

We want to increase gain in the lower frequencies, so a circuit must be designed (a passive low pass filter). 

First, measurements were taken at the X arm for impedance and capacitance, which were 104.5kOhms and 84.7pF respectively. Kiwamu decided to make the circuit resemble a voltage divider for ease of calculation, such that Vout/Vin would be a ratio of some values of the equivalent circuit reactance values. After a few algebra mistakes, this Vout/Vin value was simplified in terms of the R, C measured and the R', C' that would be needed to complete the circuit. 

Since the measured C was very small and the measure R was fairly high, the simplified form allowed us to pick values of R' and C' that would make the critical frequency occur at 0.1Hz: set the R' resistance to 1MOhm and C' capacitance to 10uF, which would yield a gain ~1.

With these values a circuit we can start actually making the circuit.

Ridiculous and hacky. Digital stabilization removed as well as the old "leave a pile of equipment on a stool" strategy.

We used a a BNC cable to send a pickoff of the beam before the recombination to the end via an SR560.

While fixing up some medm screens and getting spectra of the simulated plant, I realized that the naming convention for the Matrices of Filter banks was backwards when compared to that of the normal matrices (and the rest of the world).  The naming was incorrectly column, row.

This has several ramifications:

1) I had to change the suspensions screens for the TO_COIL  output filters.

2) I had to change the filters for the suspension with regards to the TO_COIL output filters so they go in the correct filter banks.

3) Burt restores to times previous March 11th around noon, will put your TO_COIL output filters in a funny state that will need to be fixed.

4) The simplant RESPONSE filters had to be moved to the correct filter banks.

5) If you have some model I'm not aware of that uses the FiltMuxMatrix piece, it is going to correctly build now, but you're going to have to move filters you may have created with foton.

New Focus Servo Controller has just arrived. We have 25 days to evaluate this product.

It will have to be shipped back to the vendor on April 4, 2011 the latest in order to get full refund.

The FM1 filter module change for XXSEN was propagated to the ETMX suspension.  This was a change from a 30,100:3 with a DC gain of 1 to a 3:30 which just compensates the hardware filter.

The good gains for the Sim damping were found to be:  100 for ETMX_SUSPOS, 0.1 ETMX_SUSPIT, and 0.1 ETMX_SUSYAW, ETMX_SUSSIDE is -70.  Gains much higher tended to saturate the simulated coils (i.e. hitting 10V limit) and then had to have the histories cleared for the RESPONSE matrix.

These seem to work to damp the real ETMX as well.

 John has changed the NDS2 code and restarted it on Mafalda. The issue is that it goes off the rails everytime the DAQD is restarted on FB because of filename convention war between GDS and CDS.

Until this is resolved, please make sure to restart the NDS2 process on Mafalda everytime you restart DAQD by doing this:

pkill -KILL nds2

/users/jzweizig/nds2-mafalda/start_nds2

I did some work on the ETMY real and Sim.

1. Set SUS coil gains to have the same quadropole arrangement as the magnets do (-1, 1, 1, -1) so that POS = POS instead of pringle.
2. Set the Sim Magnet polarities to match this. These are the ETMY_CI filter banks.
3. Found that the Xycom cable from the ETMY slow controls was unplugged at the Xycom side. This was preventing enabling the ETMY coil driver and so there was no real damping of the suspension going on. I plugged it in and checked that the mirror could now be moved.
4. The C1SUS_ETMY master screen's BLUE output filter area is now mis-labeled. If you trust the screen you would set it up to drive the suspension incorrectly. This MUST be fixed along with all of the other misleading features of the screen.
5. ETMY SUSSIDE filter bank had a 2048 Hz sample rate and was making the damping not work correctly. Fixed to 16384 Hz.
6. 12 Hz, 4th order Cheby low pass added and turned on for the local damping filtering. This is not optimum, but its just there to give us some filtering without introducing some instability via phase lag around 3 Hz.
7. ETMY OL beam re-aligned on ISCT-EX.
8. TM Offset buttons not working on the main overview screen.

It seems like there is still a problem with the input whitening filters. I believe the Xycom logic is set such that the analog whitening of the OSEM signals is turned ON only when the FM1 is turned OFF. Joe has got to fix this (and elog it) so that we can damp the suspension correctly. For now, the damping of the ETMY and the SETMY require different servo gains and signs, probably because of this.

4. The blue Output Filters  section has been changed to agree with the new filter of matrices row, column labeling.  My fault for not testing it and realizing it was broken.  The change was made in /opt/rtcds/caltech/c1/medm/master/C1SUS_DEFAULTNAME.adl and then ,/generate_master_screens.py was run, updating all the screens.

5.  I have swapped the logic for the sensor filter banks (ULSEN, URSEN, etc).  It now sends a "1" to the Binary Output board controlling the OSEM analog whitening when the FM1 filter is ON.  This has been done for all the suspensions (BS, ITMX,ITMY, SRM, PRM, MC1, MC2,MC3, ITMX, ITMY).

I am also updating the first sensor filter banks for the BS, ITMX, ITMY, SRM, PRM,MC1,MC2,MC3, called "3:30", to match the Y and X ends.

8.  I can't find any documentation on how to get a momentary button press to toggle states.  I could stick a filter bank in and use the on/off feature of that part, but that feels like a silly hack.  I've decided for the moment to split the TM offset button into 2, one for ON, one for OFF.  I'll put in on the list of things to have added to the RCG code (either a method, or documentation if it already exists). 

EDIT:  TM offset still doesn't work.  Will worry about it next week.

9.  Fixed a connection in SPY/SPX models where  the side senor path that was missing a constant to a modulo block.

[Joe, Alex]

Steve pointed out to me today he couldn't get trends for his PEM slow channels like C1:PEM-count_full. 

I experimented a bit and found for long time requests (over 20 days), it would produce minute trends up to the current time, but only if they started far enough back.  So the data was being written, but something was causing a problem for dataviewer/NDS to find it.

On further investigation it looks to be some incorrect time stamps at several points in the last few months are causing the problems.  Basically when Alex and I made mistakes in the GPS time stamp settings for the frame builder (daqd) code, the wrong time got written for hours to the raw minute trend data files.

So Alex is going to be running a script to go through the roughly 180 gigabytes of affected trend data to write new files with the correct time stamps.  Once it done, we'll move the files over.  We'll probably lose a few hours worth of recent trend data, depending on how quickly the scripts run, but after which minute trends should work as they are supposed to.

 Prior to the works on the Y end setup I propose to perform the temperature scan business like Koji and Suresh did before (see this entry).

This business will allow us to easily find a beatnote at 532nm after the installation on the Y end.

 I guess the right persons for this work are Bryan and Suresh.

Bryan will have a safety guidance from Steve in this after noon. So after that they can start working on it.

/* - - - coarse plan - - - */

* remove Alberto's laser from the AS table

* setup Alberto's laser on the PSL table

* put some stuff such as lenses, mirrors and etc. (Use the IR beam picked off after the doubling crystal for the main laser source)

* mode matching

* measurement

Which laser are we going to use,  Alberto's laser or MOPA laser ?

Just for a record. We got 4 new laser pointers (2 greens, 1 blue, and 1 green and red combination). Don't lose them.

They reside in a bucket on the SP table, where IR viewers and sensor cards also reside.

We use Alberto's laser for the Y end Green Locking.

The reason for using Alberto's laser is that some amount of work has already gone into characterising its phase noise.  Ref elog entry 2788

I updated our lockin simulink pieces to use the newer, more streamlined lockin piece that is currently in CDS_PARTS (with new documentation block!).  It means we are no longer passing clock signals through three levels of boxes.

In order to use the piece, you need to right click on it after copying from CDS_PARTS and go to Link Options->Disable Link.  This forces the .mdl to save all the relevant information about the block rather than just a pointer to the library.  I talked with Rolf and Alex today and we discussed setting up another model file, non-library format for putting generically useful user blocks into, rather than using the CDS_PARTS library .mdl.

The BS, ITMX, ITMY, PRM, SRM, ETMX, ETMY now have working lockins, with the input matrix to them having the 2nd input coming from LSC_IN, the 3rd from the oplev pitch, and the 4th from oplev yaw.

This necessitated a few name changes in the medm screens.  I also changed the lockin clock on/off switch to a direct amplitude entry, which turns green when a non-zero value is entered.

Currently, the Mode cleaner optic suspension screens have white lockins on them.  I started modifying a new set of screens just for them, and will modify the generate_master_screens.  Unfortunately, this requires modifying two sets of suspension screens going forward - the main interferometer optics and the MC optics.

A rough time-table and the various tasks are given below:

Note:  700mW NPRO sitting on AP table (Model No: 126-1064-700, Sl No. 415)  = Alberto's laser

PMC TRANS/REFL on MEDM showed red values for long time.
TRANS (a.k.a C1:PSL-PSL_TRANSPD) was the issue of the EPICS db.

REFL (a.k.a. C1:PSL-PMC_RFPDDC) was not physically connected.
There was an unknown BNC connected to the PMC DC output instead of dedicated SMA cable.
So they were swapped.

Now I run the following commands to change the EPICS thresholds:

ezcawrite C1:PSL-PMC_PMCTRANSPD.LOLO 0.8
ezcawrite C1:PSL-PMC_PMCTRANSPD.LOW 0.85
ezcawrite C1:PSL-PMC_PMCTRANSPD.HIGH 0.95
ezcawrite C1:PSL-PMC_PMCTRANSPD.HIHI 1

ezcawrite C1:PSL-PMC_RFPDDC.HIHI 0.05
ezcawrite C1:PSL-PMC_RFPDDC.HIGH 0.03
ezcawrite C1:PSL-PMC_RFPDDC.LOW 0.0
ezcawrite C1:PSL-PMC_RFPDDC.LOLO 0.0

As these commands only give us the tempolary fix, /cvs/cds/caltech/target/c1psl/psl.db was accordingly modified for the permanent one.

grecord(ai,"C1:PSL-PMC_RFPDDC")
{
        field(DESC,"RFPDDC- RFPD DC output")
        field(DISV,"1")
        field(SCAN,".1 second")
        field(DTYP,"VMIVME-3113")
        field(INP,"#C0 S32 @")
        field(EGUF,"10")
        field(EGUL,"-10")
        field(EGU,"Volts")
        field(PREC,"3")
        field(LOPR,"-10")
        field(HOPR,"10")
        field(AOFF,"0")
        field(LINR,"LINEAR")
        field(LOW,"0.0")
        field(LSV,"MINOR")
        field(LOLO,"0.0")
        field(LLSV,"MAJOR")
        field(HIGH,"0.03")
        field(HSV,"MINOR")
        field(HIHI,"0.05")
        field(HSV,"MAJOR")
}

grecord(ai,"C1:PSL-PMC_PMCTRANSPD")
{
        field(DESC,"PMCTRANSPD- pre-modecleaner transmitted light")
        field(DISV,"1")
        field(SCAN,".1 second")
        field(DTYP,"VMIVME-3123")
        field(INP,"#C0 S10 @")
        field(EGUF,"10")
        field(EGUL,"-10")
        field(EGU,"volts")
        field(PREC,"3")
        field(LINR,"LINEAR")
        field(HOPR,"10")
        field(LOPR,"-10")
        field(AOFF,"0")
        field(LOW,"0.8")
        field(LSV,"MINOR")
        field(LOLO,"0.85")
        field(LLSV,"MAJOR")
        field(HIGH,"0.95")
        field(HSV,"MINOR")
        field(HIHI,"1.00")
        field(HSV,"MAJOR")
}

Bryan Barr is visiting us from Glasgow for a month. He received 40m specific safety training on Friday.

- Plan for this week

  * Intensity stabilization for the end green laser (Matt / Kiwamu)

  * Hand off the servo from Green to Red (Matt / Kiwamu)

  * Y end green locking (Suresh / Bryan) (rough schedule)

  * Reconnect the X end mechanical shutter to 1X9 (Kiwamu)

  * Connect the end DCPD signal to a DAC (done)

  * Make a LPF in a Pomona box for the temperature (Larisa)

  * Clean up and finalize the X end setup (Kiwamu)

  * Make a item lists for electronics. Order the electronics. (Aidan / Kiwamu)

I added a new ADC channel for a DC signal from the X end green PD.

It is called C1:GCX-REFL_DC and connected to adc_0_1, which is the second channel of ADC_0.

By the way, when I tried connecting it to an ADC I found that most of the channels on the AA board on 1X9 were not working.

Since the outputs form the board are too small the circuits may have benn broken. See the picture below.

In addition to that  I realized that the signal from the PDH box for the temperature actuation is limited by +/- 2V due to the range of this AA board.

In fact the signal is frequently saturated due to this small voltage range.

We have to enlarge the range of this AA board like Valera did before for the suspensions (see this entry).

Some tasks for the daytime tomorrow.

  * Beam profile measurements of the Y end laser  (Suresh / Bryan)

  * Taking care of CDS and the simulated plant (Jamie / Joe)

  * Reconnect the X end mechanical shutter to 1X9 (Kiwamu)

  * LPF for the X end temperature feedback (Larisa)

 OK. Today we did the same type of measurement for the Y arm laser as was done for the X arm laser here: http://nodus.ligo.caltech.edu:8080/40m/3759 

And attached here is a preliminary plot of the outcome - oddities with adding on the fitted equations, but they go as follows

(Red)    T_yarm = 1.4435*T_PSL - 14.6222

(Blue)    T_yarm = 1.4223*T_PSL - 10.9818

(Green) T_yarm = 1.3719*T_PSL - 6.3917

It's a bit of a messy plot - should tidy it up later...

 I'm going to take the easy question - What are the pink data points??

 A comparator has been installed before the MFDs (mixer-based frequency discriminator) to eliminate the effect from the amplitude fluctuation (i.e. intensity noise).

As a result we reached an rms displacement of 580 Hz or 80 pm.

(differential noise measurement)

  Here is the resultant plot of the usual differential noise measurement.

The measurement has been done when the both green and red lasers were locked to the X arm.

In the blue curve I used only MFD. In the black curve I used the combination of the comparator and the MFD.

Noise below 3 Hz become lower by a factor of about 4, resulting in a better rms integrated from 40 Hz.

Note that the blue and the black curve were taken while I kept the same lock.

A calibration was done by injecting a peak at 311 Hz with an amplitude of 200 cnt on the ETMX_SUS_POS path.

(installation)

  Yesterday Koji modified his comparator circuit such that we can take a signal after it goes thorough the comparator.

The function of this comparator is to convert a sinusoidal signal to a square wave signal so that the amplitude fluctuation doesn't affect the frequency detection in the MFD.

I installed it and put the beat-note signal to it. Then the output signal from the comparator box is connected to the MFDs.

The input power for the comparator circuit has been reduced to -5 dBm so that it doesn't exceeds the maximum power rate.

And I'm going to answer the easy question - they're additional beat frequency temperature pair positions which seem to correspond to additional lines of beat frequencies other than the three highlighted, but that we didn't feel we had enough data points to make it worthwhile fitting a curve.

It's still not entirely clear where the multiple lines come from though - we think they're due to the lasers starting to run multi-mode, but still need a bit of thought on that one to be sure...

  - Plan for tomorrow

    * Video cable session (I need ETMY_TRNAS) (team)

    * Characterization of the Y end laser  (Bryan / Suresh)

    * LPF for the X end laser temperature control (Larisa)

    * Frequency Divider  (Matt)

    * X end mechanical shutter (Kiwamu)

Succeeded in handing off the servo from the green to the red.

(noise performance)

 This time we found that the fluctuation in the IR signals became lesser as the gain of the ALS servo increased.

Therefore I increased the UGF from 40 Hz to 180 Hz to have less noise in the IR PDH signal.

Here is a preliminary plot for today's noise spectra.

The blue curve is the ALS in-loop spectrum, that corresponds to the beat fluctuation.

The red curve is an out-of-loop spectrum taken by measuring the IR PDH signal.

Since the UGF is at about 180 Hz the rms is integrated from 200 Hz.

The residual displacement noise in the IR PDH signal is now 1.2 kHz in rms.

I am going to analyze this residual noise by comparing with the differential noise that I took yesterday (see the last entry ).

Nicely done!

Solid door, numbered 4 at south west corner of PSL enclosure was replaced by laser protective window.

The carpenter shop's Mark is making 4 more identical ones for the east side.

The Lightwave NPRO126 of 700mW was moved from the AP-table into the PSL-enclosure temporarily.

It's emergency shutdown switch can be seen at the center bottom picture

The 40m lab was visited by  ~ 30 LSC members  the end of last week.

[Joe, Alex]

Yesterday during the day, Alex ran a script to fix the time stamps in the trends files we had messed up back during the daqd change overs around Feb 17th and 23rd.  See this elog for more information on the trend problem.

Due to how the script runs, basically taking all the data and making a new copy with the correct time stamps, the data collected while the script was running didn't get converted over.  So when he did the final copy of the corrected data, it created a several hour gap in the data from yesterday during the day time.

The original files still exist on the fb machine in /frames/trend/minute_raw_22mar2011 directory.

The following is a message from the LIGO 40m Chief Recycling Officer:

Please get up off your (Alignment Stabilization Servo)es and recycle your bottles and cans!  There is a recycling bin in the control room.  Recent weeks have seen an increase in number of bottles/cans thrown away in the regular garbage.  This is not cool. 

Thank you,

---L4mCRO

This is the grand plan we talked about in the beginning of the meeting.

• (Kiwamu) X-end Green cleaning up / Prep for DRMI
• (Bryan) Y-end Green
• (Suresh) Help Bryan / RF (w. Kevin)
• (Jenne) MC WFS / Y-arm IR alignment / MC adaptive feedforward (incl. CDS)
• (Koji) LSC
• (Joe) CDS cleaning up
• (Jamie) Help Joe / Noise Budget
• (Larisa) PMC scan / PSL photo&diagram
• (Barbarela) ASS

 [Steve, Suresh, Larisa]

The following cables were laid today: ETMYT, ETMY, IFOPO, MC1, OMCR, AS Spare, and MC2T.

Though the paper suggested 135' for the MC2T, we used a 110'. This is too short: need at least another 15' for the MC2T.

The RCR cable wasn't crossed off on the list, but a cable exists at the RCR cable which is black and is labeled (old label, 75 ohms)

There was no indication of which length was needed for MC1, so a 95' cable was used.