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ID Date Author Typedown Category Subject
  4599   Mon May 2 17:10:55 2011 steveUpdateSUSPRM oplev

The returning spot diameter on the qpd ~10 mm. In order to reduce the spot size I moved the f 1145 mm lens toward the PRM ~ 25 cm. The spot size was reduced to ~8 mm, 3200 counts.

I'll try to find an other lens tomorrow.

  4600   Mon May 2 18:16:24 2011 kiwamuUpdateLSCPRMI locking : status update

(done)

- AS55 RFPD

  With a help from Jamie the AS55 RFPD was installed.

- 55 MHz demodulation board

  The AS55 demod board was installed on 1Y2.

- 3-way combiner

  ZFSC-3-13 has been installed. All the RF cables from the source side were connected to the combiner.

 

(next things)

 - installation of the REFL11 RFPD

 - DAQ check for AS55 and REFL11

Quote from #4595

(to be done in the daytime)

 - setup AS55 RFPD

 - install a demod board for 55 MHz

 - install a 3-way RF combiner on EOM.

 - prepare 55 MHz RF source (Marconi or RF source box ?)

 

  4601   Mon May 2 21:14:55 2011 kiwamuUpdateElectronicstoo loose Heliax connectors on 1Y2 rack

I found that all the Heliax cables landing on the bottom of 1Y2 were too loose.

Due to this loose connection the RF power at 55 MHz varies from -34 dBm to 3 dBm, depending on the angle of the Heliax's head.

DSC_2982_ss.jpg

 

The looseness basically comes from the fact the black plate is too thick for the Heliax cable to go all the way. It permits the Heliax's heads to rotate freely.

What we should do is to make countersinks on the black plate like this:

DSC_2984_ss.jpg

 

  4602   Mon May 2 23:29:57 2011 SureshUpdateElectronicstoo loose Heliax connectors on 1Y2 rack

The countersink gives rise to another problem when we mount the N-type-to-SMA bulkhead adaptor.  As we are making a circular hole in the plastic strip (instead of a hole with two flat sections)  the adaptor is free to turn when we tighten it with a wrench.  We currently hold the smooth circular part on the other side with a gripping pliers and while tightening.  If that part disappears into the countersink (as seen in the pics) we will not be able to tighten the adaptor sufficiently and consequently we will also not be able to get the heliax connector to be tight.

A better solution would be to use the 1/4-inch plastic L-angle beam which Steve has used on the AS table.  In addition to solving this loose connector problem, the beam is also more rigid than the plastic strip.

 

  4604   Tue May 3 03:53:20 2011 kiwamuUpdateLSCPRMI locking : done

The PRMI has been successfully locked

PRMI_locking.png

Also changing the sign of the PRC control gave me the lock of the carrier resonant condition.

The screenshot above is the time series of the error signals when I was locking the PRMI in the sideband resonant condition (i.e. carrier is non-resonant).

Note that I used REFL11 for the PRC control and AS55 for the MICH control as planed.

Details will be posted in the morning.

Quote from #4595

Today we will try to lock the PRMI.

 

  4605   Tue May 3 04:09:53 2011 KojiUpdateLSCREFL55 PD update

[Rana, Koji]

REFL55 was modified. The noise level confirmed. The PD is now ready to be installed.

 


Kevin's measurement report told us that something was wrong with REFL55 PD. The transimpedance looked OK, but the noise level was terrible (equivalent to the shotnoise of 14mA DC current).

Rana and I looked at the circuit, and cleaned up the circuit, by removing unnecessary 11MHz notch, 1k shunt resister, and so on.

I made a quick characterization of the PD.

First page:

The transimpedance ws measured as a function of the frequency. The resonance was tuned at 55MHz. The notch was tuned at 110MHz in order to reject the second harmonics. The transimpedance was ~540V/A at 55MHz. (For the calibration, I believed the DC transimpedance of 50V/A and 10000V/A for the DC paths of this PD and #1611, respectively, as well as the RF impedance (700V/A0 of #1611.

Second page:

Output noise levels were measured with various amount of photocurrent using white light from a light bulb. The measurement was perforemed well above the noise level of the measurement instruments.

Third page:

The measured output noise levels were converted into the equivalent current noise on the PD. The dark noise level agrees with the shot noise level of 1.5mA (i.e. 22pA/rtHz). In deed, the noise level went up x~1.5 when the photocurrent is ~1.4mA.

Attachment 1: REFL55.pdf
REFL55.pdf REFL55.pdf REFL55.pdf
  4606   Tue May 3 05:32:04 2011 kiwamuUpdateLSCdaytime tasks

Daytime tasks :

 - PRM & BS oplev (Steve)

 - LSC binary outputs (Joe/Jamie)

 - installation of the REFL55 RFPD (Suresh/Jamie)

 - Adjustment of demodulation phases (Kiwamu)

 - Bounce-Roll filters on BS and PRM (Suresh/Joe)

 - Suspension diagnostic using the free-swinging spectra (Leo)

 - PMC alignment (Jenne/Koji)

  4607   Tue May 3 10:21:25 2011 KojiUpdateLSCdaytime tasks

I think the installation of the PD DC signals are quite important. What to do
1) Connect the DC signals to the right top whitening board (be aware that there may be the modification of the whitening circuit).
2) Reconfigure the LSC model such that the DC signal is passed to the right channels (modify the left top part of the model)

Quote:

Daytime tasks :

 - PRM & BS oplev (Steve)

 - LSC binary outputs (Joe/Jamie)

 - installation of the REFL55 RFPD (Suresh/Jamie)

 - Adjustment of demodulation phases (Kiwamu)

 - Bounce-Roll filters on BS and PRM (Suresh/Joe)

 - Suspension diagnostic using the free-swinging spectra (Leo)

 - PMC alignment (Jenne/Koji)

 

  4608   Tue May 3 10:41:35 2011 josephbUpdateCDSMorning maintenance

1) Filled in the C1SUS_BS_OLMATRIX properly so as to make the BS oplev work for Steve.

2) Turned on the ITMX damping.  Apparently it had tripped this morning, possibly due to work in the lab area.

3) The ETMX FE controller (c1scx) had ADC timed out and died sometime around 8:30 am.  The c1x01 (the IOP on the ETMX computer) was also indicating a FB status error (mismatch in DAQ channels).

The reported error in dmesg on c1iscex was:

[1628690.250002] c1spx: ADC TIMEOUT 0 3541 21 3605
[1628690.250002] c1scx: ADC TIMEOUT 0 3541 21 3605

Just to be safe, I rebuilt the c1x01 and c1scx models, ran ./activateDAQ.py, and used the scripts killc1spx, killc1scx, and killc1x01.

I finally restarted the process with startc1x01, startc1scx, and startc1spx.  Everything is currently alive and indicating all green.

  4609   Tue May 3 10:59:31 2011 josephbUpdateCDS1Y2 binary output adapter board now powered

I temporarily turned off the power to the 1Y2 rack this morning while wiring in the binary output adapter board power (+/- 15V) into the cross connects.

The board is now powered and we can proceed to testing if can actually control the LSC whitening filters.

  4610   Tue May 3 11:49:03 2011 KojiUpdateLSCdaytime tasks

Done. C1:PSL-PMC_PMCTRANSPD was improved from ~0.75 to 0.87.

Quote:

- PMC alignment (Jenne/Koji)

 

  4611   Tue May 3 13:22:13 2011 LeoUpdateSUSRe: DRMI prep : suspension diagnostic

Here are the free-swinging spectra for the BS, ETMX, ETMY, ITMX, ITMY, MC1, MC2, MC3, and PRM chambers.  Kiwamu left the suspensions free for 5 hours this weekend, starting at Sat Apr 30 00:15:26 2011.

This is GPS time 988 182 941.  Quick tip: you can do local to GPS time conversions using lalapps_tconvert, which is a lot like tconvert but with special powers.  It is installed on pianosa.

$ lalapps_tconvert Sat Apr 30 00:15:26 2011

988182941

I generated these figures with the attached Python script, measure.py.

Notice that the C1:SUS-ITMX_SENSOR_UL and C1:SUS-MC3_SENSOR_UL spectra fall as 1/f.  Jenne suggested that this might indicate that there is a loose electrical connection.

Also, notice that C1:SUS-ETMY_SENSOR_LR, C1:SUS-ITMY_SENSOR_LL, and C1:SUS-PRM_SENSOR_SIDE are a lot noisier above 10 Hz.

Attachment 1: BS.png
BS.png
Attachment 2: ETMX.png
ETMX.png
Attachment 3: ETMY.png
ETMY.png
Attachment 4: ITMX.png
ITMX.png
Attachment 5: ITMY.png
ITMY.png
Attachment 6: MC1.png
MC1.png
Attachment 7: MC2.png
MC2.png
Attachment 8: MC3.png
MC3.png
Attachment 9: PRM.png
PRM.png
Attachment 10: SRM.png
SRM.png
  4613   Tue May 3 15:04:20 2011 kiwamuUpdateSUSRe: DRMI prep : suspension diagnostic

Jenne went through all the suspension racks and pushed all the connectors.

After pushing them, we had a quick look at those spectra and found no funny noise spectrum except for C1:PRM-SENSOR_UL.

We then checked connection around the SCSI cables and eventually found the connection between ADC_card_0 and a SCSI was loose.

We put short standoffs on the ADC card so that the screws from the SCSI can nicely reach to the ADC card. Now everything looks fine.

SUS diagnostic is quite useful !

Quote from #4611

Notice that the C1:SUS-ITMX_SENSOR_UL and C1:SUS-MC3_SENSOR_UL spectra fall as 1/f.  Jenne suggested that this might indicate that there is a loose electrical connection.

  4614   Tue May 3 15:48:26 2011 Larisa ThorneUpdateElectronicslaser temperature control LPF, final version!

This is a continuation of this

 The low pass filter is finally acceptable, and its Bode graph is below (on a ~3Hz frequency span that shows the cutoff frequency is at 0.1Hz)

Attachment 1: LPF100k.2.jpg
LPF100k.2.jpg
  4616   Tue May 3 16:20:13 2011 steveUpdateSUSPRM & BS oplevs are ready

Quote:

The returning spot diameter on the qpd ~10 mm. In order to reduce the spot size I moved the f 1145 mm lens toward the PRM ~ 25 cm. The spot size was reduced to ~8 mm, 3200 counts.

I'll try to find an other lens tomorrow.

 Atm 1,  PRM oplev inward path with 2 lens solution: 14 cm gap between F 1145 and F 1545 mm lenses. 

Atm 2,   The PRM beam size 3 mm and the beam  quality is still bad. The BS path only needed alignment.

Attachment 1: P1070630.JPG
P1070630.JPG
Attachment 2: P1070632.JPG
P1070632.JPG
  4617   Tue May 3 16:47:55 2011 kiwamuUpdateLSCPRMI locking : details

Here are some details about the PRMI locking done last night.

 

(REFL11 installation)

 REFL11 has been installed on the AP table. The RF signal from the RFPD is sent by a heliax cable which has been called ASDD133.

Before the beam goes into the RFPD a HWP and PBS are installed such that we can adjust the amount of light entering to the photo diode.

One thing I didn't like was that I had to introduce a big amount of the light into the PD to get a reasonably big RF signal.

I was trying to look for an RF signal by looking at a spectrum analyzer, then I realized that the RF signal at 11 MHz was quite tiny when the DC_MON was less than 1.5 V.

After I increased the amount of the light up to 1.9 V in DC_MON, which sounds already too much, I then got able to see the 11 MHz signal on the analyzer.

Note that I decreased the amount of the light down to 0.5 V after I finished locking the PRMI.

We should make sure what is going on with the 11 MHz modulation.

APtable.png

 

(Locking)

First I started locking the MIchelson with AS55. The demodulation phase was already somewhat optimized to the I-signal port.

So I decided not to touch the demodulation phase matrix because it may take some times.

After I eliminated electrical offsets in the digital side, I was easily able to lock the Michelson. The control sign was plus.

Then I started playing with the PRC control too. The demodulation phase in REFL11 looked nearly 45 deg although I didn't carefully measure it.

I made a 45 deg rotational matrix to maximize the I-port signal and tried to lock the PRC. Then immediately I was able to lock PRC as well as MICH.

 GAIN_MICH = 100

 GAIN_PRC = 100

Also GAIN_PRC = -100 gave a carrier resonant lock.

The control filters are the same in MICH and PRC. I used my favorite filters as usual.

 FM1 = 1000 : 10

 FM6 = 0.1 : 1

 FM7 = 1 : 50

Somehow I frequently failed to engage the boost filters (i.e. FM6 and FM7) it looks offsets in the control path kicks either BS or PRM.

Quote from #4604

The PRMI has been successfully locked

Details will be posted in the morning. 

 

  4618   Tue May 3 17:19:25 2011 kiwamuUpdateElectronicsHeliax connectors on 1Y2 rack : tightened

My observation wasn't accurate enough.

The looseness came from the fact that the N-SMA bulk heads were slipping on the black plate.

This is actually what Suresh pointed out (see here). So the thickness of the black plate doesn't matter in this case.

Somehow I was able to tighten the bulk heads using two wrenches and I think they are now tight enough so that the heliax's heads don't move any more.

Quote from #4601

I found that all the Heliax cables landing on the bottom of 1Y2 were too loose.

The looseness basically comes from the fact the black plate is too thick for the Heliax cable to go all the way. It permits the Heliax's heads to rotate freely.

 

  4620   Tue May 3 18:46:06 2011 ranaUpdateIOOMC Locking not working

I found that the MC autolocker was OFF. Kiwamu says he turned it off because its slow. Suresh says that he has some feelings that maybe something is wrong. I'll let them describe what they know about the MC in an elog.

I checked the trend of the MC and PMC transmissions for the past 30 days:

Untitled.png

Looks like the alignment has been drifitng. PMC was corrected recently by Koji, but the alignment of the input beam to the MC or the MC itself has to be fixed. Has someone been twiddling the MC SUS alignment biases??

Attachment 1: Untitled.png
Untitled.png
  4621   Wed May 4 11:48:01 2011 SureshUpdateIOOMC Locking not working

[Valera, Suresh]

The first time I noticed that the MC was not locking was after I had finished switching the RF source installation.  Before this change the RF modulation frequency (for MC) was 29.485 MHz as read from the Marconi RF Source.  We replaced this with a Wenzel crystal source at 29.491 MHz.  This may have changed the loop gain. 

Today, I changed the MC alignment to optimise the MC lock.  Valera pointed out that this is not a desirable solution since it would shift the beam pointing for all components downstream.  However, since we are not sure what was the last stable configuration, we decided to stay with the current settings for now and see the trends of several parameters which would tell us if something is drifting and causing the autolocker to fail.

The MC Auto locker is now working okay.  However to obtain lock initially we reduced the loop gain by decreasing the VCO gain.  We then increased the gain after the autolocker had locked the MC.

 

 

 

  4622   Wed May 4 12:07:48 2011 SureshUpdateRF SystemREFL55 installed on the AP table

REFL55 has been installed on the AP table.  REFL11 has been moved to make space for a 50% beam splitter. The reflected beam from this splitter is about 30% of the transmitted beam power.  The reflected beam goes to REFL11 in the current configuration.  The DC levels are 1.2V on REFL 11 and 3.5V on the REFL55.

I redid some of the cabling on the table because the we need to choose the heliax cables such that they end up close to the demod board location.  As per the 1Y2 (LSC) rack layout given here, some of the PD signals have to arrive at the top and others at the bottom of the LSC rack.

Currently the PDs are connected as follows:

 

REFL11 PD --> Heliax (ASDD133) (arriving at the top of LSC rack) --> REFL11 Demod Board 

REFL55 PD --> Heliax (REFL166) (arriving at the top of LSC rack) --> AS55 Demod Board

AS55 PD --> Heliax (AS166) (arriving at the top of the LSC rack) --> not connected.

 

We are waiting for the Minicircuits parts to modify the rest of the demod boards.

 

The heliax cables arriving at the LSC rack are not yet fixed properly.  I hope to get this done with Steve's help today.

 

 

  4623   Wed May 4 13:45:56 2011 kiwamuUpdateLSClocking last night

Last night I was trying to calibrate the MICH error signal and the actuators on BS and ITMs.

However I gave up taking the data because the MC locking was unstable. MC3 drifted a lot.

  4626   Wed May 4 13:57:04 2011 kiwamuUpdateSUSmechanical resonances updated

[Leo  w/ a little help from Kiwamu]

Leo summarized the mechanical resonances of all the suspensions, based on the free-swinging spectra taken on Sat Apr 30.

Since Leo doesn't have the wiki account I helped him putting the information on the wiki.

Good work, Leo !

http://blue.ligo-wa.caltech.edu:8000/40m/Mechanical_Resonances

Quote from

Here are the free-swinging spectra for the BS, ETMX, ETMY, ITMX, ITMY, MC1, MC2, MC3, and PRM chambers.  Kiwamu left the suspensions free for 5 hours this weekend, starting at Sat Apr 30 00:15:26 2011.

 

  4627   Wed May 4 15:22:39 2011 kiwamuUpdate Re: Intermittent MC3 UL PD signal

I went push all the possible connectors for the MC3 shadow sensors including the SCSIs, flat cables and satellite box.

Also I put screws on them so that they won't become loose any more.

As a result UL_PDMON dropped from 0.6 V to 0.490 V and it becomes stable so far.

I didn't strain relief the cables but we must do it at some point before going into the full locking test.

Quote from #4625

The attached plot shows the 30 day trend of the MC3 UL PD signal. The signal dropped to zero at some point but now it is close to the level it was a few weeks ago. There still could be a problem with the cable.

The rest of the MC1,2,3 PD signals looked ok.

 

  4628   Wed May 4 15:39:32 2011 SureshUpdateRF SystemRF Source Harmonics


I have measured the RF source harmonics in dBm using the HP 8591E spectrum analyser. There is a small discrepancy (< 1 dBm) in the value of RF power shown by the power meter and the HP8591E. This is probably due to the loss of calibration over time.

Initial problem I faced was that when we try to measure the weak harmonics, many below -50dBm we have to choose a small band as advised by Rana. However due to the large amplitide of the fundamental typically around 15dBm or so, the preamp on the spectrum analyser becomes saturated and nonlinear. This gives rise spurious harmonics not present in the source but are rather an aritifact of measurement. The power in harmonics to avoid this I used filters to selectively attenuate the fundamental component (11 or 55 MHz) and then measure the weak harmonics.

However the filters proved difficult to use, because over their stop-band they do not have an input impedance of 50 Ohm. As a result they produce unreliable power measurements for those frequency components which are within the stop band.

To get around this problem I used a suitable attenuator so that even when the internal attenuation is decreased the preamp does not saturate

All the measurements are recorded in the attached document. Pages 4 and 5 give the reliable measurements with the attenuator.

Notes:
1) At times we can see the 29.5 MHz component reflected back from the triple resonant EOM driver.
2) In the 29.5 MHz source output there is a forest of peaks around 100 MHz, which disappear after passing through the AM stabiliser. This suggests that they are associated with AM modulation and have been removed by the stabilizer. But I did not check this further.










Quote:
You should be able tosd resolve the other harmonics by decreasing the IF BW or RBW on the analyzer. Even though
they're OK, its useful to have the final measurement of all of them in some kinds of physical units (like dBm, but
not dBm/Hz or dB or dBcubits).
Attachment 1: RF_Harmonics_Sheet1.pdf
RF_Harmonics_Sheet1.pdf RF_Harmonics_Sheet1.pdf RF_Harmonics_Sheet1.pdf RF_Harmonics_Sheet1.pdf RF_Harmonics_Sheet1.pdf RF_Harmonics_Sheet1.pdf
  4631   Thu May 5 00:08:59 2011 JenneUpdateLSC(Almost) New Screens for RFPDs

I modified C1LSC.mdl to use the CDSphase blocks, which automatically calculate the R and D phase rotation for us.  Now each of the RFPDs has 2 channels in place of the old IQ_MTRX channels:  C1:LSC-RFPD_PHASE_R and C1:LSC-RFPD_PHASE_D.

I have not yet compiled / rebooted / done CDS magic to actually make these installed.  So far the change is only in the simulink model.

I was going to wait until morning to compile/reboot/magic, so I can do it under Joe's supervision.

In the meantime, I also modified the RFPD screens.  They have white boxes for the _R and _D channels just now, but that's because the new model hasn't been put in.  They now look like phase rotators, instead of Koji's temporary matrix.

Still to do:  Find the EPICS database where the phase rotation calculation is done (you give it an angle, it gives you sin(angle) and cos(angle) ).  I want to put a "90-angle" in the database so that we can type in the measured relative phase between I and Q, and it will calculate how many more degrees it needs to get to 90deg. 

 

  4633   Thu May 5 10:19:22 2011 steveUpdatePSLPSL-FSS_RMTEMP is back

Valera and I installed the the temp sensor and the interface box that Rana fixed. This may help with diagnosing the PSL drift.

Attachment 1: P1070637.JPG
P1070637.JPG
  4635   Thu May 5 13:12:06 2011 JenneUpdatePSLTemperature drift, trying to shield PMC with foil

eeek.  I've been running around all day, so this is an incomplete elog.  I'll fill in more stuff in the next hour or so, but just to let people know what's going on:

[Valera, Jenne]

Valera noticed that lots of things in and around the PSL table are drifting with temperature.  This is why he and Steve installed a temp sensor on the table earlier today.

PSL_Temp_drift_5May2011.png

Since the alignment into the PMC, and also the alignment downstream of the PMC have been drifting in angle, we supposed that it might be the PMC itself which is changing somehow with temperature.  We don't have a good idea of how exactly it is sensitive to temperature, but we're working on figuring it out.

Round 1 of testing:  We put a foil hat over the PMC to shield it from the HEPA air blowing directly down on top of it.  I made sure that the foil is also covering the PZT and the metal ring at the end of the PMC, because this could potentially be the problem (metal is usually more temperature sensitive than glass, or the PZT itself could be changing, either of which could make the end mirror twist, and change the alignment of the PMC).  We'll see later if this did anything useful or not. 

I have photos of the aluminum foil setup, which I will post later when I get back to the lab after teaching. 

P5050092small.jpg

  4636   Thu May 5 13:13:32 2011 JenneUpdateLSCNew RFPD screens are in

Joe helped me compile the lsc simulink model, and now we have R&D phase rotation.

Right now, we have to do our own math, and figure out what relative phase to put in.  Soonly, I'll figure out how to do subtraction, and we can put in the measured value.

 

More details when I'm not running around like crazy...

--------------------------------------------------------------------------------------------

Okie dokie.  Last night I had modified the c1lsc.mdl to accommodate the R & D phase rotation.  I also made pretty new screens.  This morning however, the adventures began.....

Under Joe's supervision, I ran "make c1lsc".  The error that came up was something about things not being connected.  Joe assures me that this is a temporary problem, that Rolf is already working on.  The reason is that right now the LSC model is "flat", i.e. it doesn't have a bunch of sub-boxes and sub-screens in the simulink model.  Somehow this causes badness.  Joe stuck all the guts of the LSC model into a sub-model.  He then enabled "top_names", which makes the channels use the name of the sub-model, not the sub-model AND the main model (so since the sub-model is called LSC, our channels are just C1:LSC-OTHER_STUFF, rather than C1:LSC-LSC_OTHER_STUFF).  This fixed things so that the compiling worked (when we did "make c1lsc").  The one other thing that we changed was to delete all of the little "Outs" that were attached to EPICS readouts.  These are unneccessary and don't go anywhere, and when we made the sub-model, they made a bunch of empty outputs (unconnected outs on the main simulink model).  So, after doing that, we were able to compile, and do "make install-c1lsc", and all was good in the world.  Mostly.

Joe then noticed that I was using the CDS part "cdsPhase", which only takes one phase input.  I wanted "cdswfsPhase", which actually does the R&D phase rotation that we want.  Perhaps Alex/Rolf/whoever should change the name of that CDS part.  We switched all of the cdsPhase blocks to be cdswfsPhase, and recompiled.  All was still good in the world.  Mostly.

The last thing that was funny was that when I wanted to execute the medm screens, they would still look at the old _IQ_MTRX_1_1 and _IQ_MTRX_2_1 values, rather than the newly defined _PHASE_R and _PHASE_D channels, even though while editing the medm screen, it looked like it was pointing to the right place.  Anyhow, I opened the text file version of the C1LSC_PDX.adl, and changed the channel names to the _R and _D versions by hand.  I don't know if we edit the screens and run generate_screens.py again, if we'll have to re-edit the .adl text files.

After fixing this, all really was good in the world. 

Perhaps though, this making a subsystem business broke the filters somehow?  Foton is looking at the wrong text file now?  Something?  The filters are all still there, they just got moved down a level.  Joe said that he and Rolf are on it, and he should be able to put the LSC model back to being "flat" in the next few days.

  4637   Thu May 5 13:14:15 2011 kiwamuUpdateLSCchans file for LSC

Foton doesn't correctly display the LSC filter bank file : C1LSC.txt.

Foton tells a lie that they all are empty.

 

The file itself looks fine to me i.e. I can find correct filters in text format.

Looks like someone (maybe Joe and Jenne ?) updated the file. I am not sure if this is the reason or not.

allegra:chans>ls -al | grep LSC
-rw-r--r--  1 controls controls   20659 May  5 11:46 C1LSC.txt

 

NEEDS TO BE FIXED SOON

  4638   Thu May 5 13:55:08 2011 kiwamuUpdateLSCMI locking : calibration of BS and ITMs actuators

EDIT by KI on 15/5/2011:

The calibration of MICH error signal was wrong by a factor of 2.

 

The open loop transfer functions of the Michelson locking have been measured.

The purpose of this excise is to calibrate the coil-magnet actuators on BS and ITMs.

The estimated actuation coefficients are :

 BS = 3.69e-08 [m/counts]
 ITMX = 8.89e-09 [m/counts]
 ITMY = 9.22e-09 [m/counts] 

I guess the accuracy is something like 5 % because the calibration of the MI optical gain relies on a peak-to-peak measurement.

A next step is to calibrate the PRM actuator and the PRC optical gain.


 

(measurement)

The Michelson was locked with different actuators in every measurement. I locked the Michelson to the dark fringe with BS, ITMX and ITMY in each time.

The measured peak-to-peak value in the error signal was 20.2 counts, corresponding to a sensor gain of 5.96e+07 [counts/m]. Note that I used AS55_Q for the locking.

After locking the MI I took the open loop transfer function by injecting broadband noise from DTT.

Then the data were fitted coarsely.  In the fitting I used the resonant frequencies that Leo reported recently (http://blue.ligo-wa.caltech.edu:8000/40m/Mechanical_Resonances).

The Q-values are assumed to be 5 because of the local dampings. As a result the fitting gives us the actuator coefficients.

Here is a plot showing the measured open loop transfer functions. The solid lines represent the fittings.

MICH_OL.png

 

(by the way)

- The delay time including ADC/DAC and RFM looks quite big. According to the fitting the delay is something like 600 usec.

This is about two times larger than the one reported before (see this entry). I will re-measure it with empty filters.

  4639   Thu May 5 14:40:14 2011 KojiUpdateLSCMI locking : calibration of BS and ITMs actuators

I've got confused

1) Are these the DC responses of the coils? If that is true, we need to specify the resonant frequency of each suspension to get the AC response.

2) Are these the AC responses well above the resonant freqs? In that case, The responses should be x.xxx / f^2 [m/counts]

Quote:

The open loop transfer functions of the Michelson locking have been measured.

The purpose of this excise is to calibrate the coil-magnet actuators on BS and ITMs.

The estimated actuation coefficients are :

 BS = 3.69e-08 [m/counts]
 ITMX = 8.89e-09 [m/counts]
 ITMY = 9.22e-09 [m/counts]

  4640   Thu May 5 14:50:30 2011 JenneUpdateLSCchans file for LSC

Quote:

Foton doesn't correctly display the LSC filter bank file : C1LSC.txt.

Foton tells a lie that they all are empty.

 

The file itself looks fine to me i.e. I can find correct filters in text format.

Looks like someone (maybe Joe and Jenne ?) updated the file. I am not sure if this is the reason or not.

allegra:chans>ls -al | grep LSC
-rw-r--r--  1 controls controls   20659 May  5 11:46 C1LSC.txt

 

NEEDS TO BE FIXED SOON

 See my updated elog 4636 for what Joe and I did this morning, and what a possible problem is (making the LSC model into a sub-model).

  4641   Thu May 5 15:05:06 2011 steveUpdatePSLPSL-FSS_RMTEMP is not back

Quote:

Valera and I installed the the temp sensor and the interface box that Rana fixed. This may help with diagnosing the PSL drift.

 I was wrong. Rana did not fix the interface box. I removed the interface box and turned down the HEPA flow  from 100 to 20% on the Variac.

Attachment 1: rtnfxd.jpg
rtnfxd.jpg
  4643   Thu May 5 15:28:23 2011 kiwamuUpdateLSCRe: MI locking : calibration of BS and ITMs actuators

They are the DC responses.

I put the resonant frequencies that Leo reported in the wiki to obtain the DC response.

The resonant frequencies I used are :

  f_BS = 0.957 Hz

  f_ITMX = 0.966 Hz

  f_ITMY = 0.988 Hz

Also I assumed that all the Q-values are 5 due to the damping.

Quote:

I've got confused

1) Are these the DC responses of the coils? If that is true, we need to specify the resonant frequency of each suspension to get the AC response.

2) Are these the AC responses well above the resonant freqs? In that case, The responses should be x.xxx / f^2 [m/counts]

Quote:

 BS = 3.69e-08 [m/counts]
 ITMX = 8.89e-09 [m/counts]
 ITMY = 9.22e-09 [m/counts]

 

  4645   Thu May 5 16:11:22 2011 JamieUpdateLSCchans file for LSC

Quote:

Foton doesn't correctly display the LSC filter bank file : C1LSC.txt.

 This was because of a bug in the RCG for foton filter module naming when top names is being used.  Rebuilding the LSC front-end model with top_names (which was needed to get around another bug in the RCG) broke the filter file.  I manually fixed the file, so it should work now.

  4648   Thu May 5 20:47:41 2011 KojiUpdatePSLPMC aligned

The PMC exhibited the reduction of the transmission, so it was aligned.

The misalignment was not the angle of the beam but the translation of the beam in the vertical direction
as I had no improvement by moving the pitch of one mirror and had to move those two differentially.

This will give us the information what is moving by the temperature fluctuation or whatever.

  4650   Fri May 6 06:36:18 2011 SureshUpdateRF SystemPD DC signals at each port connected

We now have the DC signal from three PDs available in the ADC channels 14,15 and 16.  The signals are from  REFL55, AS55 and POY photodiodes respectively.  As the DC signals on all the other PDs of the same port (REFL, AS and PO)  have the same information we do not need to monitor more than one DC PD at each port.

The LSC PD Interface Card, D990543 - Rev B, can take 4 PDs and provides the DC signals of the PDs on the connector P2 (the lower of the two) on the back plane of the chassis. An adaptor card, D010005-00, plugs into the back plane from the rear of the Eurorack and provides the four DC signals on two-pin lemo sockets.

I have connected the three DC signals from the relevant RF PDs (above) to a DC whitening filter, D990694-B-1 which is associated with the channels 9 to 16 of the ADC card.

The cables are in a bit of a mess right now as some of the PD power supply lines are too short to reach up the the Interface card in the top Eurocart. Steve and I plan to redo some of the cabling later today

 

 


 

  4654   Fri May 6 15:59:40 2011 steveUpdateVACTP3 fore pump replaced

Dry fore pump of TP3 replaced by brand new Varian SH-110  at  1.1 Torr_75,208 hrs

The annuloses were closed off for 25 minutes. We are back to VACUUM NORMAL mode.

The TP3 fore line pressure dropped to 44 mTorr at 25 minutes in operation.......9.4mTorr at day 2 with full annulos load

  4655   Fri May 6 17:11:55 2011 steveUpdateSUSSRM-oplev cable

The SRM qpd cable was removed from the BS-table. It's path was changed from 1x4 to ITMY-table following the inner cable tray.

  4656   Sat May 7 02:52:53 2011 kiwamuUpdateLSCTRY photo diode installed

[Suresh / Kiwamu]

 We installed the TRY photo diode (Thorlabs one) and the ETMYT CCD camera in place on the ETMY table.

Now we can see a signal on the TRY digital channel.

It will be quite useful for the Y arm locking, for instance we can do a triggered locking and the maximization of the intracavity power.

Someone has to install the EMTY trans QPD at some point.

  4657   Sat May 7 10:59:11 2011 SureshUpdateRF SystemRF Source filters changed

 

The SLP-50 filters which were on the 55 MHz lines have been replaced with the SBP-60.  Their respective characteristics are given below:

 

at 55MHz Insertion loss (dB) Return Loss (dB)
SLP-50 4.65 1.5
SBP-60 1.36 23

 

SBP-60 has lower insertion loss and higher return loss.  

This may however change the phase of I and Q in the demod boards and they will therefore need to be readjusted.  Currently the output power level of 55 MHz demod is at 2dBm, whereas it ought to be at 6dBm.   I have not yet corrected that.  Once that is completed Kiwamu will adjust the phases.

 I shifted the temperature sensor to a new location.  See the photograph below.  I noticed that the higher temperature is reached on the side where there are two RF Amps.  So it would be better to check the temperature of that  area and make sure that it remains well below 65 deg.  The operating maxium is 65deg C

 

Here is a picture of the new RF source layout.

RF_Source_Schematic.png

And here is a photograph of it

RF_Source.jpg

 

  4659   Sat May 7 18:08:54 2011 valeraUpdateIOOMC beam spot centering script

I tried to run the scripts/senseMCdecentering to check the centering of the MC beam spots on the mirrors. The script (csh) produces a lot of error messages on the control room machines. They are machine dependent combination of "epicsThreadOnce0sd epicsMutexLock failed", "Segmentation fault", "FATAL: exception not rethrown". Most of ezcawrite commands fail but not all(?). After running the mcassUp script couple of times all the dither lines came on. The MCL responses to dither lines look qualitatively similar to what it was in February (plot attached). The overall MCL spectrum looks ~100 times lower, presumably due to the analog gain reallocation.

Before that I realigned the beam into the PMC, recentered the PSL QPDs, and the beam into the MC to bring the MC RFPD_DC from ~3 to ~1.5 VDC then tweaked MC2 to bring the MC RFPD_DC from ~1.5 to ~1 VDC.

The mcass dither lines are off now and the loops are disabled.

Attachment 1: mcditherlines2.pdf
mcditherlines2.pdf
  4660   Sun May 8 16:32:52 2011 valeraUpdateIOOMC beam spot centering

 Kiwamu told me that the CDS matrix notation has changed and the 40m front end code has changed since February. I changed the senseMCdecentering script to reflect that. The other problems were: the "-" sign in ezcastep on ubuntu is not recognized - I used the known workaround of using "+-" instead; the echo command in csh script on ubuntu does not make a new line - but the echo " " does. The script ran on ubuntu with one error message "FATAL: exception not rethrown" but it finished nevertheless. The data appeared ok.  On centos machine the script produced "Segmentation fault'. The matlab script sensemcass.m now calculates the position on the MC mirrors in mm. The attached table shows the MC spot positions in mm:

    feb 26 2011      may 08 2011
MC1 pit   1.6   1.9
MC2 pit   6.4   9.0
MC3 pit   1.4   2.0
MC1 yaw   -1.5   -1.7
MC2 yaw   1.0   0.2
MC3 yaw   -1.3   -1.9

I had to rephase the lockin digital phases by tens of degrees. I don't know why this should happen at ~10 Hz.

 

  4661   Sun May 8 17:29:01 2011 ranaUpdateIOOMC beam spot centering

It seems like the best option would be to make the MCASS just adjust the SUS biases and center the beams on the suspended optics. Is this not possible somehow?

  4662   Sun May 8 22:59:40 2011 ranaUpdatePSLPSL reference cavity temperature box modifications

I looked at the PSL temperature box. It started out as D980400-B-C. Then it was revised by Peter King as per the LHO mods E020247.

There are some more things to do to it to make it useful for us:

  1. R3, 4, 7, 8, 12, & 13 should be changed from 1k to 0 Ohms, I think. I cannot figure out their purpose.
  2. All resistors should be made metal-film. Right now, its kind of a mish-mash.
  3. The active filter U6B has a corner frequency of ~50 Hz. This seems not useful for keeping the 4116 DAC noise out of the temperature. We should lower this to ~30 mHz to take advantage of the stability of the LT1021 which was put in.

** Frank reminds me that we don't use the TIdal or VME external inputs anymore since we moved to the EPICS/Perl PID control. So all we have to do is make sure these inputs are hardware disabled/disconnected.

  4663   Mon May 9 09:37:51 2011 valeraUpdatePSLPSL and MC trends

The attached plot shows 7 day trends of the MC and PMC power levels, PSL QPDs, and temperature. The MC stayed locked for ~40 hours over the weekend. The temperature swings were somewhat smaller over the past couple of days but one should remember to turn the PSL HEPA down after working on the table. Steve turned the HEPA flow from 100% down to 20% on Thursday and posted the reminder signs on the PSL enclosure.

Attachment 1: pslmcdrift2.pdf
pslmcdrift2.pdf
  4664   Mon May 9 12:33:40 2011 kiwamuUpdateLSCC1:LSC-TRIG_MTRX : wrong matrix size

I found that C1:LSC-TRIG_MTRX has a wrong matrix size. It needs to be fixed.

It is designed to have a 11x8 matrix in the simlink model file, but it's been compiled as a 6x8 matrix.

I recompiled c1lsc but it didn't fix the issue. Here below is the matrix statement in the C file :c1lsc.c. Indeed it is 6x8 matrix ....

// MuxMatrix:  LSC_TRIG_MTRX
for(ii=0;ii<8;ii++)
{
  lsc_trig_mtrx[ii] =
          pLocalEpics->lsc.LSC_TRIG_MTRX[ii][0] * lsc_imux_trigger[0] +
          pLocalEpics->lsc.LSC_TRIG_MTRX[ii][1] * lsc_imux_trigger[1] +
          pLocalEpics->lsc.LSC_TRIG_MTRX[ii][2] * lsc_imux_trigger[2] +
          pLocalEpics->lsc.LSC_TRIG_MTRX[ii][3] * lsc_imux_trigger[3] +
          pLocalEpics->lsc.LSC_TRIG_MTRX[ii][4] * lsc_imux_trigger[4] +
          pLocalEpics->lsc.LSC_TRIG_MTRX[ii][5] * lsc_imux_trigger[5];
 }

  4665   Mon May 9 13:14:48 2011 josephbUpdateLSCC1:LSC-TRIG_MTRX : wrong matrix size

[Joe, Kiwamu]

There is a feature/bug of the RCG code that you can only have 1 receiving tag for every sending tag.  There were 5 tags which were being received by two tags each, for two different matrices.  Only the first tag was receiving, the second was apparently ignored.

This has been fixed temporarily by putting in direct lines in place of these 5 tags.

Quote:

I found that C1:LSC-TRIG_MTRX has a wrong matrix size. It needs to be fixed.

It is designed to have a 11x8 matrix in the simlink model file, but it's been compiled as a 6x8 matrix.

 

  4666   Mon May 9 15:21:36 2011 josephbUpdatePSLFixed channel names for PSL QPDs, fixed saturation, changed signs

[Valera, Joe]

Software Changes:

First we changed all the C1:IOO-QPD_*_* channels to C1:PSL-QPD_*_* channels in the /cvs/cds/caltech/target/c1iool0/c1ioo.db file, as well as the /opt/rtcds/caltech/c1/chans/daq/C0EDCU.ini file.  We then rebooted the frame builder via "telnet fb 8087" and then "shutdown".

This change breaks continuity for these channels prior to today.

The C1:PSL-QPD_POS_HOR and C1:PSL-QPD_POS_VERT channels were found to be backwards as well.  So we modified the /cvs/cds/caltech/target/c1iool0/c1ioo.db file to switch them.

Lastly, we changed the ASLO and AOFF values for the C1:PSL-QPD_POS_SUM and the C1:PSL-QPD_ANG_SUM so as to provide positive numbers.  This was done by flipping the sign for each entry.

ASLO went from 0.004883 to -0.004883, and AOFF when from -10 to 10 for both channels.

Hardware Changes:

The C1:PSL-QPD_ANG_SUM channel had been saturated at -10V.  Valera reduced the power on the QPD to drop it to about 4V by placing an ND attenuator in the ANG QPD path.

  4670   Mon May 9 17:23:25 2011 SureshUpdateRF SystemRF Cables near LSC Rack

[Steve, Suresh]

We started to clean up the RF cables (heliax and PD interface cables)  at the LSC rack.

We have pulled out all the RF cables from the small hole on the side-board close to floor.  Passing the cables through this hole makes some of the cables much too short for good strain relief.  So we removed the side panel on the vacuum tube side and are going to pass the cables into the rack from there at about waist height.  We now have plenty of cable lengths to tie them off to the rack at several points.

We have traced all the available Heliax cables and have attached blank tags to them.  We have allocated some cables to REFL11, REFL55 and AS55.  These are therefore back in working order.  We have also taken stock of the available PD interface cables.  They do not have consistent names on both ends of the cable and we will identify and label the ends tomorrow.

MC is locked.  The auto-locker works fine.

Handing over the system for night time interferometer work now.  Will continue with the cabling tomorrow.

 

ELOG V3.1.3-