40m QIL Cryo_Lab CTN SUS_Lab TCS_Lab OMC_Lab CRIME_Lab FEA ENG_Labs OptContFac Mariner WBEEShop
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ID Date Author Type Category Subject
5115   Thu Aug 4 01:49:08 2011 SureshUpdateIOOMC is locked

I measured the power transmitted from the PSL to the MC. It is 19mW.

The MC is now locked.  The MC Autolocker script cannot be used now since the tigger conditions are not met.  It has been disabled on the C1IOO-LOCK_MC screen.  The boost switch also is set to zero.  Increasing the boost results in MC unlocking.

The C1:IOO-MC_RFPC_DCMON was going from 1.4 (MC Unlocked) to 0.66 (MC_locked).  I thought we ought to have a factor of ten drop in this since under high power conditions we used to have a drop of about 5.6 to 0.6.   So I adjusted the zig-zag at the end of the PSL table to improve the alignment.  It now goes from 1.4 to 0.13 when the MC is locked.   The lock is also much more stable now.  It still does not tolerate any boost though.

I checked to make sure that the beam centering on MC_REFL PD is optimal since I touched the zig-zag.  The RFPD output is now 0.7V (MC unlocked).  This matches well with the fact that we used to have 3.5V on it with the MC unlocked.  And we have cut the down the power incident on this by a factor of 5.  Because 1W -> 20mW at the PSL table  and 10% BS -> 100% Y1-...

5114   Thu Aug 4 00:04:52 2011 JennyUpdatePSLNetwork analyzer and PD set up to measure amplitude response of PZT

Today I placed the PDA255 photodiode on the PSL table to catch the small amount of beam power reflected by the second polarizing beam splitter in my setup. I plugged the PD output to the oscilloscope to measure the voltage output and positioned the PD such that the voltage output was maximized. At best I was able to achieve a 300 mV DC output voltage from the PD, (which seems a bit low, as the PD is specified to go from 0 to 5 V and the specifications say that the response becomes nonlinear after 10 mW/cm^2 and my beam has an intensity of approximately 5 mw/cm^2. I would therefore expect to get more beam power but after over an hour of maneuvering, 300 mV was the highest voltage output I could get).

I am planning, tomorrow afternoon, to take a measurement of the amplitude response of the PZT driving the NPRO laser. I moved the 4395 spectrum/network analyzer to near the PSL table and connected the RF output to an RF splitter. I fed one output of that into the PZT and the other output into the R port on the network analyzer. I fed the PD output into the A port. I plan to measure A/R as a function of driving frequency, sweeping from 10 Hz to 30 mHz.

I also worked to improve the mode matching of the NPRO beam coming from the AP table to the reference cavity. I drove the temperature of the NPRO at 0.100 Hz with an amplitude of 0.300 V, which Koji told me corresponds to a 1GHz change in the laser frequency. The transmission from the cavity is being monitored by a camera connected to a TV monitor, and also by a PD connected to an oscilloscope. I then repositioned the second lens in my mode matching setup in an attempt to increase the transmission peaks from the zeroth order spacial mode and decrease the transmission peaks from higher order modes. I may have improved the mode matching slightly but I was unable to improve it significantly.

5113   Wed Aug 3 22:31:38 2011 KojiUpdateLSCREFL33 PD

REFL33 is ready for the installation

Characterization results of REFL33 is found in the PDF attachment.

Resonance at 33.18MHz
Q of 6.0, transimpedance 2.14kOhm
shotnoise intercept current = 0.52mA (i.e. current noise of 13pA/rtHz)

Notch at 10.97MHz
Q of 22.34, transimpedance 16.2 Ohm

Notch at 55.60MHz
Q of 42.45, transimpedance 33.5 Ohm

Attachment 1: REFL33_test_110801_KA.pdf
5112   Wed Aug 3 22:22:47 2011 KojiUpdateLSCREFL165 PD

This REFL165 was good in terms of RF, but I forgot to make the DC path functioning.

I will try some ideas to fix this tomorrow.

5111   Wed Aug 3 16:18:30 2011 steveUpdateVACvent is almost finished

P1 at 750 Torr,  Vent valve VV1 is left open to atm. It will reach equilibrium in an hour. The PSL power is not turned down yet. The beam path is blocked at two places inside the enclosure.

The low power 20 mW  input  MC can be locked tonight.

Next day's - Thursday notes:

We  reached 760 Torr of atm in 8 hrs at  1.7 Torr/ min with 5 cylinders of  instrument grade air.

Used 500 PSI of nitrogen to get to 20 Torr at first.  This flow  and the first cylinder of N2  has to be slower next time.

We did the following:

1, oplevs were centered on locked caveties 2 days ago

2, just before vent we rechecked arms  pointing, they wre still locking

3,eloged strain gages  and turned HVs off at PZT-steering   at 1Y3 rack and OMC-PZT ps at 1X2 aux rack. They were actually off.

4,,checked jam nuts 6 places x 3

5, turned oplev servos off

6, eloged SUS summery page

7, checked particle counts at ITMY: 1 micron 300,  0.5 micron 3K,  0.3 micron  30K particles / cft-min. All three cranes were wiped 2 days ago.

8, blocked laser into IFO: main 1064 in 1.25W were blocked by manual 2 blocks on PSL table. The PSL output shutter was left open to be triggered by interlock  at P1 3 mTorr. It did!

Aux NPRO-AP and green light  input at both ends were blocked.

Attachment 1: vent8h.jpg
5110   Wed Aug 3 14:40:32 2011 kiwamuSummaryGeneralminutes of 40m meeting : plan tomorrow

Tomorrow's main goal is : let the both X and Y green light come out from the chambers.

Plan of the in-vac work for tomorrow :

- Removal of the access connector and the BS north door, starting from 9:00 AM. (requires 6 people)

- If necessary, align ITMs and ETMs to get the green light nicely flashing / locked.

- Take pictures of the BS and IOO table before installing / repositioning some optics.

- Repositioning of the green periscope in the BS chamber to let the Y green light go through it.

- Steer some green mirrors on the IOO table to let the Y green light come out from the chamber.

- Steer some green mirrors on the BS table to let the X green light come out from the chamber.

- Put some beam traps on the BS table

- Leveling of the BS table. (Do we need to level the IOO table ? it will change the spot positions on the MC mirrors somewhat)

- Take pictures again.

- Extra jobs : if we still have some more times, lock MC and check the beam clearance at the Faraday. Also check some possible beam clippings for the IR beam.

- Close the chamber with the light doors.

- Softball game at 6:30 PM.

5109   Wed Aug 3 14:20:49 2011 steveUpdateSUSITMX and PRM damping restored

ITMX watchdog tripped around 5 Torr  and the PRM around 450 Torr of this vent. They were restored than.

We are at 580 Torr now.

5108   Wed Aug 3 12:37:57 2011 KojiSummarySUSWeekly Summary

I vote for making an adapter plate between the sliding plate and the bottom base.

 Quote: This morning, I realized that the current set-up of the horizontal shaker does not allow for the TT to be securely mounted. I was going to change the drill holes in the horizontal slider base (1 inch pitch). Jamie has suggested that it is better to make a pair of holes in the base larger. The circled holes are the ones that will be expanded to a 0.26" diameter so that I can mount the mirror securely to the horizontal slider base. There is a concern that a bit of the TT suspension base will hang over the edge of the horizontal sliding plate. We are not sure if this will cause problems with shaking the mirror evenly. Suggestions/advice are appreciated.

5107   Wed Aug 3 12:27:01 2011 NicoleSummarySUSWeekly Summary

This week I have determined the linear region for my photosensor. I have determined the linear region to be -14.32 V/cm in the region 0.4cm 0.75 cm.

In order to obtain this voltage plot, I used a 287K resistor to set the max voltage output for the photodiodes. This calibration was obtained using a small rectangular standing mirror (not the TT testing mirror that Steve has ordered for me).

I have also been working on the second half of the photosensor circuit (to power the LED and read out voltages for the second photosensor head). I have assembled the constant-current section of the circuit and need to do the voltage-output section of the circuit. I also need to finish assembling the second photosensor head and cables.

I submitted my Second Progress Report on Tuesday.

I have attached the mirror to the TT suspension. We are using 0.006 diameter tungsten wire to suspend the mirror. I am currently working on balancing the mirror.

This morning, I realized that the current set-up of the horizontal shaker does not allow for the TT to be securely mounted. I was going to change the drill holes in the horizontal slider base (1 inch pitch). Jamie has suggested that it is better to make a pair of holes in the base larger. The circled holes are the ones that will be expanded to a 0.26" diameter so that I can mount the mirror securely to the horizontal slider base. There is a concern that a bit of the TT suspension base will hang over the edge of the horizontal sliding plate. We are not sure if this will cause problems with shaking the mirror evenly. Suggestions/advice are appreciated.

Attachment 1: calibrationplot.jpg
Attachment 2: calibrationplot.jpg
5106   Wed Aug 3 12:24:08 2011 Manuel, IshwitaUpdateWienerFilteringWeekly summary

Last Friday (Jul 29) we reinstalled the blue breakout box, and changed the names of the C1:PEM channels. Elog Reference

We continued the work on the simulation ad applied wiener filter on the simulated ground motion, but the result is unsatisfactory, yet. We will post reasonable results soon.

We did wiener filtering for the first time on real data from the Xarm while it was locked. Elog Reference

5105   Wed Aug 3 11:34:59 2011 kiwamuUpdateVACRe: vent

An important rule during the in-vac work :

Do not change the incident axis of the X and Y green beams.

Because of the air flows and unusual pressure in the chambers, the DC alignment of the suspensions become less reliable in terms of the beam pointing reference.

The green beams will be considered as references during the vent.

 Quote: The vacuum system is coming up to atm. The vent was started with slow N2 flow.

5104   Wed Aug 3 09:40:13 2011 steveUpdateVACvent

The vacuum system is coming up to atm. The vent was started with slow N2 flow. The PSL output is blocked 2 places on the table.

Attachment 1: pzt2011Aug3.png
5103   Wed Aug 3 04:29:48 2011 kiwamuUpdateIOOpeparation for low power MC : HWP+PBS installed

[Suresh / Kiwamu]

The incident beam power going into MC was decreased down to 20 mW by rotating the HWP that we set yesterday.

A 10% beam splitter which was sitting before MCREFL_PD was replaced by a perfect reflector so that all the power goes into the PD.

And we confirmed that MC can be still locked by increasing C1IOO-MC_REFL_GAIN. Some modifications in the Autolocker script need to be done later.

Also we opened the aperture of the MC2F camera to clearly see the low power beam spot.

WE ARE READY FOR THE VENT !!

Power after the EOM = 1.27 W

Power after the HWPs and PBS = 20.2 mW

Power on MCREFL = 20 mW (MC unlocked)

MCREFL_DC = 0.66 V (with MC locked)

 Quote: After we finish the measurement we will go to the low power state.

5102   Wed Aug 3 02:28:08 2011 Manuel, IshwitaUpdateWienerFilteringWiener Filtering in X-arm

Wiener Filtering was applied on the data collected from the X-arm during the time: GPS time-996380715 (Aug 02, 2011. 21:25:00. PDT) to GPS time-996382215 (Aug 02, 2011. 21:50:00. PDT) for a duration of 1500 seconds. During this time the X-arm was locked, we checked it by acquiring data from channel C1:LSC-TRX_OUT_DQ .

The seismometers were near the beam splitter (guralp2) and near MC2 (guralp1).

Target data was obtained from channel C1:LSC-XARM_IN1_DQ.

Following graphs were obtained after applying the Wiener filter:

1.Seismic data acquired from Guralp1 (X and Y) and Guralp2 (X and Y)                              2.Seismic data acquired from Guralp2 X                                                              3.Seismic data acquired from Guralp2 Y

These graphs were obtained with srate = 2048 (sample rate) and N = 20000 (order of the filter).

Graph 1 is the best because the black (residual) line is below the red (target) line for low frequencies since we used seismic data from 4 channels. Graph 3 is the worst because we used seismic data from only one Y channel (Y axis of Guralp2) that is less related with the X-arm mirrors' motion since they are oriented orthogonally.

5101   Wed Aug 3 02:20:33 2011 KojiUpdateLSCREFL165 PD

REFL165 PD has been made from the old 166MHz PD.
As the required inductance was ~10nF level, the stray inductance of the circuit pattern was significant.
So, I am not so confident with the circuit functionality before the optical transfer function test.

I will test REFL33 and REFL165 with the Jenne laser to see how they work.

Attachment 1: REFL165_schematic_110802_KA.pdf
5100   Wed Aug 3 01:30:04 2011 JenneUpdateLSCAbsolute length of Xarm and Yarm measured

So far, this is just preliminary, because I haven't done full error analysis to determine the error on my measurements.  That will hopefully be done by tomorrow afternoon (so before we start taking off doors).

I find that the length of the Xarm is:  37.5918 meters.

I find that the length of the Yarm is:   37.5425 meters.

I used the mass-kicking technique, as summarized by Kiwamu, and fully described by Alberto.  More words / description to follow with the full error analysis.

5099   Tue Aug 2 23:14:21 2011 NicoleUpdateSUSCorrected Screw Alignment in TT Suspension Base

The TT suspension base was not able to be securely mounted to the optical table (i.e. mounted with 4 screws)

because the spacing between the screw holes in the base did not have the correct spacing for mounting on a table with a 1 inch pitch.

We have carefully removed the suspension from the problematic base. PLEASE BE VERY CAREFUL AROUND THE TABLE NEXT TO THE MC-2 CHAMBER! THE TT SUSPENSION IS RESTING THERE WITHOUT THE BASE! I will reattach it to the base tomorrow morning when I am less tired and more careful!

We measured the base to be about 4.882" x 3.774". The screw hole spacing is about 3.775" and 2.710" respectively. I have changed the diameter of the screw holes from 0.26" to 0.315" and have been able to successfully mount the suspension to the 1 inch pitch table next to the MC-2 chamber.

Now that the TT suspension can be mounted, I am going to be aligning a 670nm LED laser and balancing the mirror on the TT tomorrow morning. I will be using a beam blocker but please still be careful.

5098   Tue Aug 2 23:02:48 2011 NicoleUpdateSUSFixed Accelerometer

The EM shaker was broken (the input terminals (banana inputs) had snapped off. To fix this, I have mounted two banana input mounting posts to a metal mount that Steve attached to the shaker.

However, because bananas do not provide a secure connection (they easily fall out), I have made special wires to connect the banana inputs of the shaker to the mounted banana inputs of the amplifier I am using (along with the sine generating function of the HP 3563A signal analyzer). Upon Koji's suggestion, I have made C-shaped clips to attach to the banana post mounts. These clips are made from insulated ring terminals.

Today I tested the  shaker and it works! WOOT! I currently have the shaker attached to the horizontal sliding platform (without the TT suspension on it).

Using a 750mHz signal from the HP 3563A with an amplitude of 500 mV amplified to 0.75V, I have gotten the shaker to displace the platform (without the TT suspension on it) 1 mm.

5097   Tue Aug 2 19:05:13 2011 kiwamuUpdateIOOpeparation for low power MC : HWP+PBS installed

[Steve / Kiwamu]

An attenuator, consisting of two HWPs and a PBS, has been installed on the PSL table for the MC low power state.

Those items allow us to reduce the amount of the incident power going into the MC.

We haven't decreased the power yet because we still have to measure the arm lengths.

After we finish the measurement we will go to the low power state.

We have adjusted the polarization after the last HWP using another PBS. Now it is S-polarizing beam.

After the installation of the attenuator the beam axis has changed although we were immediately able to lock the MC with TEM00 mode.

I touched two steering mirrors on the PSL table to get the transmitted power of MC higher. At the moment the transmitted power in MC_TRANS is at about 30000 cnts.

The attached picture is the setup of the attenuator on the PSL table.

Attachment 1: attenuator.png
5096   Tue Aug 2 17:40:04 2011 JennyUpdatePSLReducing beam intensity incident on photodiode

I am using a PDA255 photodiode to measure the power outputted by the NPRO beam on the PSL table. (I'm going to then use a network analyzer to measure the amplitude response of the PZT to being driven at a range of frequencies. I'll detect the variation in in response to changing the driving frequency using this PDA255.)

The PDA255 has an active area of 0.8mm^2 and a maximum intensity for which the response is linear of 10mW/cm^2. This means that a beam I focus on the PD must have a power less than 0.08 mW (and even less if the spot size is smaller than the window size).

I used a power meter to measure the beam power and found it was 0.381 mW.

The second polarizing beam splitter in the setup transmits most of the beam power, but reflects 0.04 mW (according to the power meter). I'm going to place the photodiode there in the path of the reflected beam.

5095   Tue Aug 2 16:55:21 2011 ranaUpdateABSLArm length measurement : cavity kick technique

 Quote: I made some attempts to measure the current length of the arm cavities by using the mass-kicking technique.

Why not just scan the Green laser to measure the arm lengths instead? The FSR of the arm is ~3.75 MHz and so all you have to do is lock the arm green and then sweep the PZT until the resonance is found at 3.75 MHz.

5094   Tue Aug 2 16:43:23 2011 jamieUpdateCDSNDS2 server on mafalda restarted for access to new channels

In order to get access to new DQ channels from the NDS2 server, the NDS2 server needs to be told about the new channels and restarted.  The procedure is as follows:

ssh mafalda
cd /users/jzweizig/nds2-mafalda
./build_channel_history
./install_channel_list
pkill nds2
# wait a few seconds for the process to quit and release the server port
./start_nds2


This procedure needs to be run every time new _DQ channels are added.

We need to set this up as a proper service, so the restart procedure is more elegant.

An additional comment from John Z.:

The --end-gps parameter in ./build_channel_history seems to be causeing
some trouble. It should work without this parameter, but there is a
directory with a gps time of 1297900000 (evidently a test for GPS1G)
that might screw up the channel list generation. So, it appears that
the end time requires a time for which data already exists. this
wouldn't seem to be a big deal, but it means that it has to be modified
by hand before running. I haven't fixed this yet, but I think that I
can probably pick out the most recent frame and use that as an end-time
point. I'll see if I can make that work...

5093   Tue Aug 2 15:41:06 2011 kiwamuUpdateIOOMeasurement of MC spot positions : done

[Suresh / Kiwamu]

The measurement of the spot positions on the MC mirrors are DONE.

Surprisingly the spot positions are not so different from the ones measured on May.

 Feb 26 2011 May 08 2011 (New !) Aug 2 2011 MC1 pit [mm] 1.6 1.9 1.93 MC2 pit [mm] 6.4 9.0 9.03 MC3 pit [mm] 1.4 2.0 2.01 MC1 yaw [mm] -1.5 -1.7 -1.72 MC2 yaw [mm] 1.0 0.2 0.178 MC3 yaw [mm] -1.3 -1.9 -1.87

(some notes)
We used Valera's script senseMCdecenter to estimate the spot positions ( see his entry).

It returns so many EPICS error messages and sometime some measured values were missing. So we had to throw away some of the measurements.

Anyways we gave the resultant ASCII file to Valera's matlab file sensmcass.m to get the actual amount of off-centering in milli-meter.

The attached file is the resultant plot from his matlab code.

Attachment 1: MCdecenter.png
5092   Tue Aug 2 11:52:44 2011 kiwamuSummaryGeneralSchedule

I have updated the 40m public calender.

Main change :

+ The vent starts from 3rd of August

+ Keiko and Anamaria (LSU) come from 13th of August

5091   Tue Aug 2 11:02:52 2011 JenneUpdateSUSPRM Watchdog tripped

I found PRM watchdog tripped.  It's all better now.

5090   Tue Aug 2 10:53:03 2011 JenneOmnistructureSAFETYRegular door out of service. Use Control Room Door only!!

The hazardous waste people are moving chemicals around outside our door, and have roped off our regular front door.

Please go around, and use the control room door to enter and exit.  It is currently unlocked, although I'll lock up when I leave for LIGOX.

5089   Tue Aug 2 02:35:23 2011 kiwamuUpdateGeneralpreparation of the vent : status and plan

The vent will take place on Wednesday.

Plan for Tuesday :

(Morning) Preparation of necessary items for the low power MC (Steve / Jamie)

(Daytime) Measurement of the MC spot positions (Suresh)

(Daytime) Arm length measurement (Jenne)

(Nighttime) Locking of the low power MC (Kiwamu / Volunteers)

Plan for Wednesday :

(Early morning) Final checks on the beam axis, all alignments and green light (Steve / Kiwamu / Volunteers )

(Morning) Start the vent (Steve)

(daytime-nighttime) Taking care of the Air/Nitrogen cylinders (Everybody !!)

Status of the vent preparation :

(not yet) Low power MC

(ongoing) Measurement of the arm lengths

(ongoing) Measurement of the MC spot positions

(80% done) Estimation of the tolerance of the arm length (#5076)

(done) Alignment of the Y green beam (#5084)

(done) Preparation of beam dumps (#5047)

(done) Health check of shadow sensors and the OSEM damping gain adjustment (#5061)

(done) Alignment of the incident beam axis (#5073)

(done) Loss measurement of the arm cavities (#5077)

5088   Tue Aug 2 02:20:09 2011 kiwamuUpdateGreen LockingY arm green beam axis : done

I succeeded in locking the green light to the Y arm cavity, but it wasn't so robust. Something is unhealthy in the electronics.

I am leaving the Y green system as it is because I already can see a plenty of the green light flashing in the BS chamber.

So just a flashing of the green light is good enough for the in-vac-work.

DONE.

 Quote from #5084 The next step is to refine some electronics in the PDH loops to get the green light locked to the Y arm cavity.

5087   Mon Aug 1 23:29:24 2011 Manuel, IshwitaUpdateWienerFilteringGetting Data by matlab

We tried to acquire data from the seismometers and the mode cleaner using the Matlab function

datalist = NDS2_GetData({'C1:PEM-SEIS_GUR1_X_IN1_DQ'}, 996258376 , 10, CONFIG.nds.C)

and encountered the following error

Warning: daq_request_data failed

??? Error using ==> NDS2_GetData
Fatal Error getting channel data.

The same error was obtained with the following other channels

C1:PEM-SEIS_GUR2_X_IN1_DQ

C1:PEM-SEIS_STS_1_X_IN1_DQ

But we are able to get data from channel

C1:LSC-MC_OUT_DQ

for the same gps time.

We checked with Dataviewer that the data are saved (we viewed data of last 24h) for every channel.

5086   Mon Aug 1 23:26:32 2011 KojiUpdateLSCREFL33 PD

Old MZ PD (InGaAs 2mm, @29.5MHz) has been modified for REFL33.
There has been no choice for the 11MHz notch other than putting it on the RF preamp
as the notch in parellel to the diode eats the RF transimpedance at 33MHz.

I wait for judgement of Rana if the notch at the MAX4107 feedback is acceptable or not.

Attachment 1: REFL33_schematic_110801_KA.pdf
5085   Mon Aug 1 22:30:59 2011 kiwamuSummaryGeneralWeekly report

Summary of the week ending July 31st.  Number of elog entries = 53

- SUS
+ ETMY-LR sensor looked strange. Something wrong.
+ Responses from the DC alignment bias to the shadow sensors and the oplevs were checked.
--> ETMY shows the response with the opposite sign. Wired.
+ ETMY shadow sensors were examined in terms of the spectra.
--> WF, AA and ADC noise looks reasonably low and not high enough to explain the low frequency noise.
+ Adjusted all the OSEM gains

- LSC
+ MICH noise budget is ongoing. WF filter needs to be greater than 21 dB to have dark noise of the PD greater than ADC noise
+ The arms became lockable

- CDS
+ modified and re-ran activateDQ.py.
+ c1iscex crashed for unknown reasons and we physically rebooted it.

- ALS (Fiber experiments)
+ PMC trans is sampled for the fiber beat-note measurement on the PSL table.
+ The beat-note signal between PSL and X end laser were obtained.
+ Some optics in the ETMY table were rearragend to have the Y green light aligned.

- ACS / ASS
+ incident beam axis has changed a lot.
+ X arm and Y arm ASS were reactivated.
---> The sign of some of the control gains had been wrong.
+ The incident beam axis and X/Y arm were re-aligned

- IOO/MCWFS
+ Some medm screens fixed.
+ Adjustment of the demodulation phase on each quadrant on WFS1 and WFS2 are done.
+ The sensing matrix (from optics to WFS sensors) were measured.

- OAF
+ c1pem was modified
+ plugged a seismometers to ADC through an AA board.
--> channels are coming to the digital land

- Preparation for the invac work
+ 7 pieces of beam traps are available
+ Tolerance of the arm length is estimated to be +/- 2 cm.

- PSL/RefCav
+ ABSL is injected into the reference cavity. some flashing happened but no locking.
+ eddited the psl.db file to set EGUF and EGUL
+ turned RefCav heater and servo back on

5084   Mon Aug 1 20:21:05 2011 kiwamuUpdateGreen LockingY arm green beam axis : aligned

The beam axis of the Y green light has been aligned.

Now I can see TEM00 mode is flashing on the ETMY camera.

-- (What I will do tonight)

The next step is to refine some electronics in the PDH loops to get the green light locked to the Y arm cavity.

If the beam isn't locked, I guess the in-vac-work will be so difficult because of the low intensity of the green light.

According to a brief check on the circuits, a low pass filter after the demodulation mixer is in a sad situation.

It doesn't pass any signals and in fact it behaves more like an absorber.

On the other hand, the modulation system looks fine to me because I was able to see the 270 kHz sideband converted into AM due to the fringing.

 Quote from #5078 (not yet) Alignment of the Y green beam (#5066)

5083   Mon Aug 1 17:47:37 2011 steveUpdateASCwhat is not working

SUS-ETMY_QPD is not responding. It is reading zero in dataviewer and 4,400 counts on QPD MEDM screen.......must be wrong cable connected

IP-POS is sick. Last time alive 7-19-2011

IP-ANG beam is clipping on pick-up mirror at ETMY chamber. This will have to be fixed at the vent. The qpd itself is responding to light.

5082   Mon Aug 1 16:06:05 2011 steveUpdateSUSoplevs are centered

Kiwamu, Koji and Steve,

Arm aligned separatly and oplev qpds were centered  including BS. Than we realigned manually DRM and centered their qpds.

ALL SUS oplevs were centered to resonating cavities.

5081   Mon Aug 1 11:46:56 2011 ranaSummaryLSCTolerance 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.

5080   Mon Aug 1 08:52:37 2011 steveUpdateVACpreparation to vent

Both arms locked easely around 1V transmited.  We should recenter oplevs.

Attachment 1: pztsteering.png
Attachment 2: vac1Aug2011.png
Attachment 3: PEM200d.jpg
5079   Mon Aug 1 04:08:24 2011 kiwamuUpdateABSLArm length measurement : cavity kick technique

I made some attempts to measure the current length of the arm cavities by using the mass-kicking technique.

However unfortunately I am running out my energy to complete the measurement,

so I will finish the measurement at some time today.

I still have to set an appropriate kick amplitude. Right now I am injecting AWG into ETMY_LSC_EXC at 0.2 Hz with amplutde of 400 cnts.

I guess it needs a little bit more amplitude to get more psuedo-constant velocity.

Volunteers are always welcome !

(some notes)

The procedure was well-described in entry #555 by Dr.Stochino.

Here is just an example of the time series that I took today showing how the time series looks like.

5078   Sun Jul 31 22:48:35 2011 kiwamuSummaryGeneralpreparation of the vent : status update

Status update for the vent preparation:

The punchline is : We can not open the chamber on Monday !

##### Task List for the vent preparation #####

(not yet) Low power MC

(not yet) Measurement of the arm lengths

(not yet) Alignment of the Y green beam (#5066)

(not yet) Measurement of the MC spot positions

(80% done) Estimation of the tolerance of the arm length (#5076)

(done) Preparation of beam dumps (#5047)

(done) Health check of shadow sensors and the OSEM damping gain adjustment (#5061)

(done) Alignment of the incident beam axis (#5073)

(done) Loss measurement of the arm cavities (#5077)

Quote from #5048

 Quote: The vent will start from 1 st of August !

5077   Sun Jul 31 22:35:35 2011 kiwamuUpdateLSCarm loss measurement : done

I did the measurement of the arm loss on both X and Y arm by running the armLoss script.

The results will be posted later.

 Quote from #5074 I will measure the loss on the X and Y arm cavity tomorrow.

5076   Sun Jul 31 17:28:34 2011 kiwamuSummaryLSCTolerance 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)
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.

5075   Sun Jul 31 00:37:57 2011 kiwamuUpdatePSLRe : PSL table work

I think you made a simple mistake in your diagram -- the mixer must be replaced by a summer circuit. Otherwise you cannot do the PDH lock.

 Quote from #5069

5074   Sun Jul 31 00:05:52 2011 kiwamuUpdateLSCscript for loss measurement : modified

I modified the script armloss so that the channel names in the script are properly adopted to the new CDS.

Additionally I disabled the ETMX(Y)_tickle command in the script.

The tickle command puts some offsets on the LSC signal to let the arms pass through a fringe until it gets locked, but apparently we don't need it because the arms are loud enough.

A brief check showed that the script ran fine.

I will measure the loss on the X and Y arm cavity tomorrow.

 Quote from #5067 Next : Health-check for the X arm ASS, the loss measurements.

5073   Sat Jul 30 21:04:23 2011 kiwamuUpdateASCY arm ASS fixed

The X arm ASS was also fixed. So both X and Y arm ASS are now back to normal.

Now we can align the arms any time from the buttons on the C1IFO_CONFIGURE window.

(notes)

The reason why the servo didn't work was that the sign of some control gains had been flipped.

This was exactly the same situation as that in the Y arm ASS (#5067).

 Quote from #5067 The servos of C1ASS for the Y arm and the beam axis alignments were fixed.

5072   Sat Jul 30 20:41:50 2011 ranaUpdatePSLRefCav Stabilization back on

I turned the RefCav heater and servo back on a couple days ago. At first it was stabilizing again at a low setpoint, but in reality the right temperature (~40 C). After fixing the in-loop signal offsets, the setpoint now correctly reflects the actual temperature.

Jenny is going to calibrate the sensors using some kind of dunking cannister next week.

5071   Sat Jul 30 19:06:25 2011 ryan, ranaUpdatePSLReturn of the PSL temperature box

 Quote: The PSL temperature box has returned to service, with some circuit modifications. The 1k resistors on all the temp. sensor inputs (R3, R4, R7, R8, R12, R12) were changed to 0 Ohm. Also, the 10k resistors R26, R28, R29, and R30 were changed to 10.2k metal film. The DCC document will be updated shortly. There is now an offset in the MINCOMEAS channel compared to the others, which will be corrected in the morning after looking at the overnight trend.

Forgot to do this in May. Have just changed the values in the psl.db file now as well as updating them live via Probe.

To make the appropriate change, I took the measured offset (5.31 deg) and added 2x this to the EGUF and EGUL field for the MINCO_MEAS channel. (see instructions here)

Committed the .db file to the SVN.

attached plot shows 8 days of trend with 5.31 degC added to the black trace using the XMGRACE Data Set Transformations

Attachment 1: rctempbox.png
5070   Sat Jul 30 10:03:32 2011 JennyUpdateComputer Scripts / ProgramsMode matching

I ended up having to switch to a different mode-matching solution, because I was unable to find the f = 572.7 mm lens. See my next elog entry (5069).

5069   Sat Jul 30 10:01:35 2011 JennyUpdatePSLPSL table work

I've been working on the PSL table to put together a setup so that I can measure the reference cavity's response to a temperature step increase at the can surrounding it. My first step was to mode match the beam coming from the AP table to the cavity.

I implemented my mode matching solution. I ended up using a different one from the one I last elogged about. Here is the solution I used:

Two lenses: f = 1016.7.6 mm at -0.96 m and f = 687.5 mm at -0.658 m. (I set my origin at the polarizing beam splitter--the spot where I want my beam to match the beam coming from the PMC, so all waists are behind that point). Below is what it should look like.

What I did on the table:

• Before placing lenses I aligned the beam and added a 1/2-wave plate between the two polarizing beam splitters to change the polarization of the beam from S to P.
• I aligned the beam so that it reflected off of the cavity opening (monitoring the reflected power with a photodetector connected to an oscilloscope and tweaking the alignment to maximize the reflected signal).
• I then placed the lenses at -0.93 and -0.64 mm because the exact spots were blocked by optics being used in another setup.
• I reasoned that since the fitting for the initial waist is so uncertain, the lens position being off by a few cm will not produce the dominating source of error. I am now driving the laser frequency using a lock-in as a function generator to drive the laser temperature at ~1 Hz. I'm then monitoring the power transmitted by the reference cavity with a camera connected to a TV monitor. I will use this setup to improve my mode matching.

Here's a picture of the PSL table with the lenses and mirror I added. The beam is redirected by a mirror and then a polarizing beam splitter. Past the beam splitter is another lens (f=286.5 mm), which was already in place from the mode matching of the beam from the PMC to the reference cavity.

Here is a block diagram of my intended experimental setup:

I am going to try to lock the laser to the cavity given my preliminary mode matching and then go back and improve it later. My next step is to find a frequency range for dithering the voltage sent to the PZT. To do this I will:

• Measure the transfer function (amplitude response) of the PZT using a photodiode. The power outputted by the laser varies with driving frequency.
• Find a frequency region in which the amplitude response is low.
Attachment 3: LIGO_block_diagram.png
5068   Sat Jul 30 07:07:28 2011 kiwamuUpdateASCMCASS status

Since we will measure (and hopefully adjust) the spot positions on the MC suspensions prior to the vent, MCASS is necessary for it.

#######################

Here is the MCASS status so far:

+ Valera worked on MCASS on the last February, and basically no progress after he left.

+ The MCASS model had been completed in C1IOO.mdl.

+ He made some useful scripts, including mcassup, mcassOn/Off, senseMCdecenter, senseMCmirrro and senseMCdofs.

Summary of those scripts can be found in his entry #4355.

+ We haven't closed the MCASS loops.

+ The control filters are still blank.

+ We haven't put any elements on the input and output matrices.

+ Some parameters for the dithering oscillators and demodulation systems were properly set.

So we can get the demodulated signals by simply running mcassUp and mcassOn. (This essentially corresponds to the A2L measurement.)

+ The PIT motions are driven at 10, 11 and 12 Hz for MC1, 2 and 3 respectively. For YAW, the frequencies were chosen to be 11.5, 12.5 and 13.5 Hz.

+ Some medm windows were prepared but not as refined as that of ASS.

+ Valera performed a measurement of the spot positions by using MCASS. The results are summarized in #4660.

+ We made an estimation about the beam clearance on the Faraday based on the measured spot positions (#4674)

#########################

So, it seems we should be able to at least measure the spot positions soon by using his scripts.

5067   Sat Jul 30 06:24:06 2011 kiwamuUpdateASCY arm ASS fixed

The servos of C1ASS for the Y arm and the beam axis alignments were fixed.

Now we can correctly run the Y arm ASS from the C1IFO_CONFIGURE window as usual.

The sign of some control gains had been flipped for some reasons, so I changed them to the correct signs.

Next : Health-check for the X arm ASS, the loss measurements.

 Quote from #5062 I tried using C1ASS to align the incident beam and suspensions on the Y arm, but it didn't work.

5066   Sat Jul 30 05:11:45 2011 SureshUpdateGreen LockingY- end table clean-up

The optics on the Y-end table which required to be moved have been repositioned.  Please see the attached pic for details.

The green beam is not yet aligned to the cavity. That is my next task.

ELOG V3.1.3-