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1. Y-arm alignment for IR

Basically we gradually have to move onto the Y-arm locking at some point.

Prior to it we need to align the Y arm for IR. Probably we have to touch PZT1 and PZT2.

It would be very nice if the X-arm alignment also gets improved together with this work.

2. Temperature feedback with a digital control for X end PDH lock

Need a temperature feedback not with an analog way but with a digital way because we want to put an offset and the feedback signal at the same time (#4198).

Right now the temperature control input of the laser is connected to a slow DAC (#3850).

Probably we should plug the feedback signal from the PDH box to the fast ADC (i.e. c1iscex), and then connect a fast DAC to the laser temperature.

This entry maybe helpful.

3. Calibration of optical gain for IR arm locking

In order to evaluate the performance of the green locking, one of the key points is the IR PDH signal.

Because it tells us how much the motion of the X arm is suppressed at IR when the green lock is engaged.

To get this information in m/sqrtHz, we need to know the optical gain.

4. MC servo characterization and PSL frequency noise measurement

SInce the green beat note tells us the frequency difference between the MC and the arm in the current configuration, we should know how the MC servo is.

Along with this work, I need someone to measure the PSL frequency noise, when it is locked to the MC over the frequency range from 0.01Hz to 1kHz.

5. PLL characterization

Solve this issue (#4195) and make it reliable.

9667

Mon Feb 24 23:43:10 2014

1) Fixup REFL165: remove ND filters, get box for PD, dump diode reflections, put less light on diode, change DC transimpedance (?), max power dissipation on BBPD < 0.5 W w/ 25 V bias. Perhaps replace OP27 with TLE2027.

2) Make plan for fixing fiber layout up and down the arms. Need tubing for the whole run. Don't make it cheesy. Two fibers per arm.

3) Fix LSC model to allow user switching of whitening. Get back to working on AutoLock scripts (not Guardian).

4) Manasa, Q, Jenne, tune Oplev servos Tuesday morning/afternoon.

5) Reconnect the other seismometers (Steve, Jenne). For real.

6) Balance PRMI coils at high frequency.

Thu Nov 1 19:53:02 2007

Attachment 1: DSC_0053.JPG

4282

Mon Feb 14 01:19:18 2011

This is just a listing of CDS problems I still notice today:

MC2-MCL button was left ON due to BURT failure. This, of course, screws up our Green locking investigations because of the unintended feedback. Please fix the BURT/button issue.
The GCV - FB0 status is RED. I guess this means there's something wrong? Its really a bad idea to have a bunch of whited out or falsely red indicators. No one will ever use these or trust these in the future.
MC1/2/3 Lockins are all white. Also, the MODE switches for the dewhitening are all white.
Is the MC SIDE coil dewhitening filter synced with anything? It doesn't seem to switch anything. Maybe the dewhite indicators at the top right of the SUS screens can be made to show the state of the binary output instead of just the digital filter
MC WFS is all still broken. We need a volunteer to take this on - align beams, replace diodes, fix code/screens.

4285

Mon Feb 14 07:58:43 2011

I am concentrating on the RF system just now and will be attending to the RF PDs one by one. Also plan to work on some of the simpler CDS problems when I overlap with Joe. Will be available for helping out with the beam alignment.

4309

Wed Feb 16 23:54:34 2011

ETMX cannot load his filter coefficients. Even if I change the file, the load button doesn't work. I tried changing the lockin filters but they won't load.
The ETMX filter modules appear to have 2048 for some of the modules and 16384 for some of the others. How come the make script doesn't make them all 16384?
There are a bunch of kill/start scripts in the scripts/ directory instead of in the scripts/FE/ directory. Did this get reverted after a new code exchange?
I tried restarting the code using c1startscx, but that doesn't work correctly. It cannot find the burtrb and burtwb files even though they are in the normal path.
Kiwamu was using a bunch of cockamamie filters I found.
I can't get any minute trend data. I tried on rossa, rosalba, and op440m.

MC damp

dataviewer

diaggui

AWG

c1lsc

c1ioo

c1sus

c1iscex

c1iscey

RFM

The Dolphins

Sim.Plant

Frame builder

TDS

Cabling

5214

Fri Aug 12 17:27:49 2011

Yoichi

Summary

CDS

Toggle button for RCG

Bottom line: I made an RCG block to realize a toggle button easily.

Read on if you need such a button, or if you want to know how to
write a new RCG block with C.

-----------------
When I was making MEDM screens for FFC, I wanted to have a toggle
button to enable/disable the FFC path.
I wanted to have something like the ON/OFF buttons of the filter bank
screens, the one changes its state every time I click on it.
However, I could not find an easy way to realize that.

From MEDM, I can send a value to an EPICS channel using a "Message Button".
This value is always the same, say 1.
In the RCG model, I used a cdsEpicsMomentary block so that whenever the channel
gets 1, it stays to be 1 for a while and turns back to 0 in a second or so.
This generates a pulse of 1 when I click on a message button on a MEDM screen.
Then I needed a block to keep its internal state (0 or 1), and flips its state
whenever it receives a pulse of 1.
Since I couldn't find such a block in the current RCG library, I implemented one
using the cdsFunctionCall block. It allows you to implement a block with C code.

There is a good explanation of how to use this block in the CDS_PARTS library.
Here is basically what I did.

(1) Drag and drop thee cdsFunctionCall block to my model.

(2) In the "Block Properties", I put the following line in the Description field.

inline cdsToggle /opt/rtcds/caltech/c1/userapps/release/cds/common/src/cdsToggle.c

This means to call a function cdsToggle(), whose code is in the file indicated above.

(3) The contents of the source code is very simple.

void cdsToggle(double *in, int inSize, double *out, int outSize){
  static double x = 0;
  static double y = 0;

  if (*in != y){
    y = *in;
    if (y == 1){
      x = (x == 1) ? 0 : 1;
      *out = x;
    }
  }
}

The function prototype is always the same. *in and *out are the pointers to the arrays of doubles
for input and output signals of the block. In simuLink, the signals have to be
multiplexed so that the RCG can know how many signals are handed to or returned from the function.
In order to keep the internal state of my custom block, I used "static" keyword in the
declaration of the variables. The rest of the code should be obvious.

(4) Just compile the model as usual. The RCG will automatically include the source code and put
a call to the function in the proper place.

I made the block a library so that people can use it.
/opt/rtcds/caltech/c1/userapps/trunk/cds/common/models/cdsToggle.mdl
is the one.
For the usage of it, please have a look at
/opt/rtcds/caltech/c1/userapps/trunk/isc/c1/models/c1lsc

16485

Wed Nov 24 17:13:31 2021

The toilet tank in the big bathroom stopped refilling. I contacted PPService@caltech.edu and put up an "Out of Order sign".

16487

Tue Nov 30 11:03:44 2021

a plumber came in yesterday and fixed the issue.

Quote:

The toilet tank in the big bathroom stopped refilling. I contacted PPService@caltech.edu and put up an "Out of Order sign".

483

Fri May 16 17:27:55 2008

Andrey

Omnistructure

General

Toilets are broken, do not use them !!!

Both toilets in 40-meter were constantly flushing, the leaking water was on the floor inside of the restrooms, so

BOTH RESTROOMS ARE CLOSED TILL MONDAY

I have heard the constant loud sound of flushing water, opened the door, and was unpleasantly surprised because all the floor was under the layer of water and the toilets were constantly flushing. I called security at X5000, a plumber came in and told that a team of plumbers needs to repair the flushing system after the weekend. The plumber today just shut off the flushing water, wiped off the floor and told not to use the restrooms in the weekend. We should expect a team of plumbers on Monday.

Sinks are working, so you can wash your hands.

5076

Sun Jul 31 17:28:34 2011

kiwamu

Summary

LSC

Tolerance of Arm length = 2 cm

Required arm length = 37.7974 +/- 0.02 [m]

This is a preliminary result of the estimation of the Arm length tolerance.

This number was obtained from a simulation based on Optickle.

Note that the simulation was done by considering misplacements in only the arm lengths while keeping PRCL, SRCL and MICH at the ideal lengths.

Therefore the tolerance will be somewhat tighter if misplacements in the central part are taken into account.

Next : check 3f signals, and include misplacements in PRCL, SRCL and MICH.

(Background)
We will re-position the ETMY/Y suspensions to adjust the arm lenghts during the coming vent.
To get a reasonable sensing matrix for LSC, the arm length must be adjisted within a certain precision.
So we need to know the tolerance of the arm lengths.

(How to estimate)
Optickle, a frequency domiain interferomtere simulator, is used to model the response of the 40m interferometer.
I buit a 40m model in Optickle, and in this model every optical distance is adjusted to the perfect length.
Then some offsets are added on the macroscopic position of ETMs to see what will happen in the LSC sensing matrix.
When putting the offsets, the amount of offsets are randomly assigned with a Gaussian distribution (see Figure.1).
Therefore the calculation is a Monte-Calro style, but this doesn't have to be a Monte-Calro

because the parameter space is only 2-dimensions (i.e. X-arm and Y-arm length) and it can be done by simply scanning the 2-dimentional parameter space.
The reason why the Monte-Calro style was chosen is because I wanted to expand this simulation

to a more general simulation which can handle PRCL, SRCL and MICH misplacements as well.

This time I ran the Monte-Calro 1000 times.

Figure.1 History of random walk in X-Y arm lengths parameter space.

The position of ETMY and ETMX are randomly chosen with a Gaussian distribution function in every simulation.

This example was generated when \sigma_x = \sigma_y = 2 cm, where \sigma is the standard deviation of

the Gaussian function. The number of simulation is 1000 times.

(Criteria)
I made two criteria for the acceptable sensing matrix as follows :

(1) The decrease in the optical gain of the important signals (diagonal signals) must be within a factor of 3 (factor of ~ 0.5 in log scale).

(2) MICH and SRCL signals are separated within a range of 60 - 120 deg in their demodulation phases on POP55.

(Results1 : sensing matrix)

Figure.2 shows the resultant sensing matrix with histograms when \sigma_x = \sigma_y = 2,

where \sigma_x, \sigma_y are the given standard deviation in the position of ETMX and ETMY.

The diagonal signals (in red-rectangular window) shows variation in their optical gain within a factor of 0.5 in log scale (factor of 3 in linear scale).

This satisfies my requirement (1) mentioned in the last section.

Figure.2 A sensing matrix of the 40-m DRFPMI while changing the position of ETMX/Y by \sigma = 2 cm.

For convenience, only REFL11, AS55, POP11 and POP55 are shown. They are the designed signal ports that

mentioned in the aLIGO LSC document (T1000298). In all the histograms, x-axis represents the optical gain in log scale in units of [W/m].

The y-axis is the number of events. The diagonal ports are surrounded by red rectangular window.

(Results2 : demodulation phase of MICH and SRCL on POP55)

Now a special attention should be payed on the MICH and SRCL signals on POP55.

Since MICH and SRCL are designed to be taken from POP55, they must be nicely separated in their demodulation phases.

Therefore the demodulation phase of MICH and SRCL has to be carefully examined.

The plot in Figure.3 is the resultant phase difference between MICH and SRCL on POP55 when \sigma_x = \sigma_y = 2 cm.

As shown in the plot the phase are always within a range of 60 - 120 deg, which satisfies my requirement (2) mentioned in the last section.

Figure.3 Difference in the demodulation phase of MICH and SRCL on POP55.

x-axis is the difference in the demodulation phase of MICH and SRCL, and y-axis the number of events.

(Notes on the Optickle model)
Optickle that I used is the one downloaded from the MIT CVS server and I believe this is the latest version.
In my current simulation I omitted some foldng mirrors including PR3, SR2 and SR3.
If those mirrors are added on the model, loss from those mirrors will affect the build up powers in all the cavities and hence changes the sensinag matrix somewhat.
I assumed that each optic has loss of 50 ppm in its HR surface.
Input power, after the MC, of 1 W is assumed.
The modulation depth are all 0.1 rad for 11MHz and 55MHz.
The model files were uploaded on the MIT CVS server and files reside under /export/cvs/iscmodeling/40m/fullIFO_Optickle.
More information about the CVS server can be found on aLIGO wiki.

5081

Mon Aug 1 11:46:56 2011

rana

Summary

LSC

Tolerance of Arm length = 2 cm

wow. This Monte-Carlo matrix is one of the most advanced optical modeling things I have ever seen. We never had this for any of the interferometers before.

5273

Sat Aug 20 00:42:22 2011

Keiko

Update

LSC

Tolerance of PRC, SRC, MICH length = 2 mm ?

Keiko, Kiwamu

I have run Kiwamu's length tolerance code (in CVS iscmodeling, ArmTolerance.m & analyseArmTorelance.m ) for the vertex ifo.

In his previous post, he monte-carlo-ed the arm lengths and saw the histogram of the sensing matrix and the demodulation phase between POP55 MICH and POP55 SRCL. From these plots, he roughly estimated that the tolerance is about 1 cm (sigma of the rondom gaussian) and in that case POP55 MICH and SRCL is separated by the demodulation phase 60-150 degrees.

This time I put the length displacements of random gaussian on PRC, SRC, MICH lengths at the same time (Fig.1).

Fig. 1. History of random walk in PRC, SRC, MICH lengths parameter space. Same as Kiwamu's previous post, The position of the three degrees are randomly chosen with a Gaussian distribution function in every simulaton. This example was generated when \sigma = 1 cm for all the three lengths, where \sigma is the standard deviation of the Gaussian function. The number of simulation is 1000 times.

When the sigma is 1 cm, we found that the sensing matrix is quite bad if you look at Fig. 2. In Fig.2 row POP55, although the desired degrees of freedoms are MICH and SRCL, they have quite a bit of variety. Their separation in the demodulation phase is plotted in Fig.3. The separation in the demodulation phase varies from 40 degrees to 140 degrees, and around 270 degrees. It is not good as ideally we want it to be 90.

Fig. 2 Histgram of the sensing signal power in the matrix when 1 cm sigma rondom gaussian is applied on PRC, SRC, MICH lengths. x axis it the signal power in log10.

Fig.3 POP55 MICH and POP55 SRCL separation with the displacement sigma 1 cm.

Kiwamu suspected that PRC length as more strict tolerance than other two (SRC, MICH) for POP55, as 55MHz is fast and can be sensitive to the arm length change. So I ran the same monte-carlo with SRC, MICH displacements but no PRC displacements when sigma is the same, 1cm. The results were almost same as above, nothing obvious difference.

With 2mm sigma, the signal power matrix and the POP55 MICH and POP55 SRCL separation in the demodulation phase look good (Fig. 4 and Fig. 5).

Fig.4 Signal power matrix when PRC, SRC, MICH lengths fractuate with random gaussian distribution with 2mm sigma. The signal powers are shown in log10 in x axis, and they do not vary very much in this case.

Fig.5 POP55 MICH and POP55 SRCL separation with the displacement sigma 2 mm. The separation of the two signal is 60-90 degrees, much better than when sigma is 1 cm. We may need to check 60 degree separation is really ok or not.

PRC SRC MICH lengths tolerances of 2 mm in the real world will be very difficult !

Next I will check what happens on 3f signals.