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  40m Log, Page 95 of 341  Not logged in ELOG logo
ID Date Authorup Type Category Subject
  3109   Wed Jun 23 18:05:00 2010 KojiConfigurationPSLFSS SLOWDC should be ~-4.0

FSS SLOWDC slider is at around 0.

Please someone relock this at ~-4.0 to exploit some last juice of the fruit.

See this entry for the details of the operating point.


Attachment 1: C1PSL_FSS.png
  3135   Tue Jun 29 14:16:35 2010 KojiConfigurationSAFETYBack in LASER HAZARD mode.

The insects and the laser trouble... Strange coincidences with LHO surprised me, but now I have been relieved.


[Steve, Kiwamu, Jenne]

The 40m is now back in Laser Hazard mode.  Safety glasses are required for entry into the LVEA / IFO room.


  3164   Wed Jul 7 10:42:29 2010 KojiSummaryPSLpower spectral density from RefCav transmitted beam

How do you calibrate this to Hz/rtHz?


I measured the RC transmitted light signals here at the 40m. I made all connections through the PSL patch panel. No optics/PD were touched.

I measured the spectral density of the signal of the transmitted beam behind RefCav in both time and frequency domain.

This will be compared with the result from PSL lab later, so I can see how stable the signal should be.

We re-aligned the beam into the cavity (the DC level increased from 2 V to 3.83V)

and the reflected beam to the center of the RFPD.



  3175   Wed Jul 7 23:11:08 2010 KojiUpdateIOOMC alignment values.

Hmm. I expect that you will put more details of the work tomorrow.
i.e. motivation, method, result (the previous entry is only this),
and some discussiona with how to do next.


Nancy and Koji:

This is what I and Koji measured after aligning the MC in the afternoon.

MC_Trans 4.595 (avg)

MC_Refl 0.203 (avg)

MC2_trans :

power = 1.34mW

13.5% width : x=6747.8 +- 20.7 um  , y = 6699.4+- 20.7 um



  3191   Mon Jul 12 02:21:01 2010 KojiConfigurationASCResurrection of MC WFS

I have resurrected the MC WFS on Friday night.
I have uncommented the WFS part of the MC autolocker.
The WFS total gain was empirically set to 0.1 such that the loops have no instability.

The loops somewhat worked through the weekend although they seemed to have the drift of the operating points
in accordance with the WFS spot.

  3201   Mon Jul 12 22:01:13 2010 KojiUpdateSUSOne TT suspended. Still need fine alignment

Jenne and Koji

We tweaked the alignment of the TT mirror.

First we put a G&H mirror, but the mirror was misaligned and touching the ECD as the magnet was too heavy. We tried to move the wires towards the magnet by 1mm.
It was not enough but once we moved the clamps towards the magnet, we got the range to adjust the pitching back and forth.
We tried to align it by the feaher touch to the clamp, we could not get close to the precision of 10mrad as the final tightening of the clamp screws did change the alignment.

We will try to adjust the fine alignment tomorrow again.

The damping in pitch, yaw and longitudinal looks quite good. We will also try to characterize the damping of the suspension using a simple oplev setup.

Attachment 1: IMG_2634.jpg
  3228   Thu Jul 15 15:57:10 2010 KojiConfigurationLSCPRC and SRC length adjustements

Tell me whether it is correct or not. Otherwise I won't be able to sleep tonight.


According to these results, these would be the proposed adjustements to the cavity lengths:
dl(PRC) = -0.0266 m; dl(SRC) = 0.612 m

  3264   Thu Jul 22 03:08:27 2010 KojiUpdateIOOVent and MC lock


- The vacuum chambers have been vented.

- The north heavy door of the BS chamber has been opened by Genie (not by the crane).
It was replaced by the light door. The door is currently closed.

- The MC has been locked with 20mW incident and aligned. MC REFL was left unchanged but lock was able to be achieved.

- The optics before MCT CCD and MCT QPD have been adjusted for the low power operation.


- The first HWP for the variable optical attanuator (HWP/PBS/HWP pair) was set to be 86deg from the maximum transmission at 126deg.
The incident power of 19mW has been measured.

- The PSL mechanical shutter has been manually opened. Two other beam blocks has been removed.

- I found the MC was totaly misaligned with no resonance.- I tried to align it based on the previous OSEM values but in vain.

How to align the MC mirrors from the scratch

- MC1 has been aligned so as to maximize REFL PD and DC signal of WFS QPDs.

- MC3 has been aligned by looking at the scattered light on the MC2 frames. The spot is centered on the MC2 approximately.

- MC2 has been aligned so that any resonance is seen in MC_F.

Modification of the MCT optics

- The ND filter before the MCT was removed.

- The Y1-45S mirror before the MCT CCD, which is also used to steer the beam to the MCT QPD path, was replaced to BS1-50-45P.
The reason I used 45P is to obtain higher reflectivity. Because S has higher reflectivity than P in the each layer, I expected to have higher reflectivity for S than 50%.

- The MC REFL path has not been untouched.

Modification of the servo

- The lock was attempted after alignment of the mirrors.  Here how to lock the MC is described below.

1. Run script/MC/mcloopson

2. Open the MC Servo screen in MEDM

3. Change the input gain from 6dB to 22dB.
Change offset from 0.78 to -0.464 (such that the length output has no offset).
Change VCO Gain from 3dB to 21dB

Change MC Length path Gain from 0.3 to 1.6

  3300   Tue Jul 27 16:33:50 2010 KojiSummaryGeneralHigh school students tour

Jenne made the 40m tour for the annual visit of 30-40 students.


Tour 2009 http://nodus.ligo.caltech.edu:8080/40m/1717

Tour 2008 http://nodus.ligo.caltech.edu:8080/40m/737


Attachment 1: IMG_2657.jpg
  3318   Thu Jul 29 12:31:09 2010 KojiSummaryGeneralLab Schedule

29 Thu BS chamber work: Move cable towers / green steering mirrors / (2 TTs with TT charactrization) / Put the heavy door by 5PM.
30 Fri Pumping down
31 Sat WFS work by Nancy

1 Sun - 5 Thu WFS work by Nancy
5 Thu PSL Table prep
6 Fri PSL Table prep / Likely to shut down the PSL

9 Mon PSL Table prep / shutting down of the PSL (optional)
10 Tue PSL box Frame lifting
12 Thu PSL table tapping

16 Mon - 17 Tue concrete pouring preparation
19 Thu - 23 Fri Tripod placement
24 Tue - 26 Thu concrete pouring

Attachment 1: PSL_work_schedule.pdf
  3329   Fri Jul 30 02:54:04 2010 KojiUpdate40m UpgradingMore optics installed on the BS table

July 29 Thu [Steve, Alberto, Kiwamu, Koji]

We placed some optics in the BS chamber.
The chambers are ready to be pumped down on Friday once the heavy door is placed.

- Clean room work

  • Engraved two Y2 mirrors and PBS@532nm
  • Engraved three DLC mounts
  • Each of the mounts needs a 3.5 inch post. We found there is no stock of the post in the lab! Also the clamps!
  • Took the posts from the temporarily removed optics although we need to return those optics into the table during the next vent.
  • We should count the # of the mounts and count the needed posts. Posts and clamps can be either a DLC thick post or New Focus pedestal.

- In the chamber

  • The terminal holder was moved as Alberto described
  • The green steering optics were placed as Alberto described
  • Note: the PBS is flipped in the mount (reflection side is back side)
  • The table leveling
  • Releasing EQ stops / Check OSEMs / Adjust OSEMs (BS OSEMs are untouched)

- After closing the chamber

  • The BS OSEM mumbo-jumbo


[Koji, Steve, Kiwamu, Alberto]

- This afternoon we installed a few new optics on the BS table: GR_PBS, GRY_SM2, GRY_SM1.

- We pulled up the cables so that we had more freedom to move one of the cable towers farther South.

- Then we re-leveled the table. PRM OSEMs were adjusted to be nominal insertions.

- Koji released the earthquake stops on BS but the readout of the OSEMs was apparently frozen on the MEDM screens.
Initially we thought it was a software problem. a nuclear reboot didn't solve it. We spent the following three hours investigating the cause.
Eventually it turned out that the earthquake stops on BS weren't actually fully released.

We opened the tank and accessed to BS. Releasing the earthquake stops in full solved the issue. The OSEMs readout went back to normal.


  3332   Fri Jul 30 12:46:38 2010 KojiConfiguration40m UpgradingBS chamber status
Attachment 1: BS_layout_Jul_29_2010.png
  3335   Fri Jul 30 17:52:12 2010 KojiConfigurationGeneralJacket

Jenne and I need our jackets. We removed them from the Rb clock.
Thanks for making them warm.
Probably a Scotland sweater would fit.

  3338   Fri Jul 30 22:07:42 2010 KojiHowToVACHow to stop and start slow pumpdown

Kiwamu and Koji

The rough pumping was stopped at 230mmTorr. We are going to resume the pumping tomorrow morning.

  • RV1 was closed with torque wheel.
  • V3 was closed from MEDM
  • RP3 wss stopped from MEDM
  • The quick coupling to RP3 was disconnected.


    How to stop: 1, close RV1 by torque wheel  2, close V3 from MEDM screen  3, turn off RP3 roughing from MEDM screen  4, disconnect metal hose to oily pump

after butterfly valve. This KF-45 O-ring seal should be kept clean 5, place/close  45 mm cover blanks at the end of the hose and and on the 5" nipple. 

    How to start: 1, remove blanks from  hose and nipple 2, reconnect roughing pump hose to RV1 nipple  3, turn on PR3  4, open V3  5, open RV1 by wrench to ~3/8

6, fine tune RV1 opening to 1 Torr/min

ESSENTIAL: one operator has to be present when oilly roughing pump is connected to the vac. envelope

  3343   Sat Jul 31 22:35:01 2010 KojiUpdateVACVac-P1 still 1.2mtorr

I resumed the pumping from 19:00.

Now the valve RV1 is full open. But the pumping is really slow as we are using only one RP.

After 3hrs of pumping, P1 reached 1.2mmtorr but still we need 2hrs of pumping...

I stopped pumping at 22:30.

  3344   Sun Aug 1 18:50:35 2010 KojiUpdateVACP1 = 0.48 torr

I resumed the pumping today. Now the pressure is 0.48 torr. The pump was stopped.


I resumed the pumping from 19:00.

Now the valve RV1 is full open. But the pumping is really slow as we are using only one RP.

After 3hrs of pumping, P1 reached 1.2mmtorr but still we need 2hrs of pumping...

I stopped pumping at 22:30.


  3348   Mon Aug 2 17:12:28 2010 KojiUpdateGeneralLab schedule for the week of Aug. 2


2 Mon - 5 Thu WFS work (Nancy)

2 Mon - 4 Wed

Jenne: Seismometer fix / Seismic measurements on the PSL table
TT characterization (with Koji)
Preparations ETM suspensions (optional: may be in later weeks)

Kiwamu: CDS test for SUS (may be involving Koji)

Alberto: RF system prep.

All: For 5th and 6th: PSL cabling works Koji

5 Thu PSL Table prep
6 Fri PSL Table prep / Likely to shut down the PSL

9 Mon PSL Table prep / shutting down of the PSL (optional)
10 Tue PSL box Frame lifting
12 Thu PSL table tapping

16 Mon - 17 Tue concrete pouring preparation
19 Thu - 23 Fri Tripod placement
24 Tue - 26 Thu concrete pouring

Attachment 1: PSL_work_schedule.pdf
  3350   Mon Aug 2 21:52:57 2010 KojiUpdateIOOMC is running at the full power

[Nancy and Koji]

We restored the full power operation of the MC.

Restoration of the suspensions

  1. Found the suspension watch dogs are left turned off.
  2. Found c1susvme1/2 were not running.
  3. Launched the realtime processes on c1susvme1/2 and c1iscey
  4. Restored the watch dogs. The suspensions looked fine.

Preparations for the high power

  1. Put an ND2.0 before the MCT CCD. Confirmed the ND reflection is damped.
    MCT QPD is not necessary to be touched.

The high power operation of the MC / post lock adjustment

  1. Locked the MC under the autolocker being disabled.
  2. Adjusted the aperture on the MC2 face camera
  3. Adjusted the spot positions on the WFS QPDs
  4. Reverted the scripts to the high power ones
    (mcup / mcdown / autolockMCmain40m)
  5. Logged in to op340m and restarted autolockMCmain40m

The autolocker seems working correctly.

  3355   Wed Aug 4 01:44:56 2010 KojiConfigurationPEMAccelerometer located on and below the PSL table

[Jenne and Koji] 

In order to characterize the seismic vibration of the PSL table, we put the accelerometers on and below the PSL table.

On the PSL: MC2 Accelerometers (X, Y, Z) - being connected to CH1-3 of the preamps
East side of the PSL table. X, Y, and Z is directed to North, East, and Up.

On the ground: MC1 Accelerometers (X, Y, Z) - being connected to CH4-6 of the preamps
Beneath the West side of the PSL table. X, Y, and Z is co-aligned to the MC2 ACC.

I found that the C1:PEM-ACC_MC1_Z has large noise in the low freq (~1Hz) region. I tracked down the noise source
and found the noise is still present in the down stream even when the CH17 (C1:PEM-ACC_MC1_Z) of the ADC IF BNC
(@1Y7) was terminated.

I consulted with Jenne and decided to connect this channel to CH14, which is vacant and has name
C1:PEM-AUDIO_MIC2 (16k).
(for the details of the channel configurations, see /cvs/cds/caltech/chans/daq/C1ADCU_PEM.ini)

I first tried magnetometer channels to steal, but they didn't seem reacting (and the connected to the wrong channels).
I am feeling that we should once entirely check the I/F box.

Note that there looks the difference of the gain by x10 between C1:PEM-ACC_MC* channels and C1:PEM-AUDIO_MIC2.

[From Jenne:  The gain difference is because the C1:PEM-ACC_MC* channels have gain=10 in the .ini file, while C1:PEM-AUDIO_MIC2 uses the default gain=1. ]

Attachment 1: IMG_2675.jpg
Attachment 2: IMG_2678.jpg
Attachment 3: IMG_2682.jpg
  3364   Thu Aug 5 00:17:41 2010 KojiUpdatePSLPSL preparation work

We start the work on the cables at around the PSL table.

Aug 5th 10am-4pm?: (Kiwamu, Alberto, Koji)
- Removal of the unused cables around the PSL table and the control room
- Removal of the cable ties on the PSL frame

- Removal of the big nuts at the side of the PSL table

Aug 6th 10am-4pm?: (Kiwamu, Alberto, Koji, Jenne (~noon) )
- Labeling of the cables
- Planning of the disconnection

Aug 9th  9am-5pm: (Steve, Jenne, Alberto, Koji)
- Shutting down of the PSL
- Disconnection of the cables
- Draining of the cooling water
- Removal of the accelerometers
- Removal of the PSL chamber
- Sealing of the table with the plastic sheets

  3367   Thu Aug 5 13:05:53 2010 KojiUpdateIOOMode Cleaner WFS

Upon Nancy's request, I checked the status of the suspensions.

I found that the power strip of the 1Y4 rack was turned off.
Since it has a over current breaker, I don't know whether it happened by someone or over current.

Anyway, I restarted the sus computers, and now the suspensions are damping as usual.
The MC has been aligned, the auto locker is also working.

Incidentally, I found that the WFS servos are not working. Actually since the last night
It repeated losing lock and unlock.

Probably some values of the matrix or the gain is wrong.
I left the WFS as it is because Nancy will put new values this afternoon.
I will ask her to confirm that the old values work at the end of her work.

  3369   Thu Aug 5 17:59:23 2010 KojiUpdatePSLCable removal from the control room

[Alberto, Kiwamu, and Koji]

We removed the BNC cables from the control room.
The work was as hard as the one I had when I swept a 300m tunnel with a vacuum...

If we could remove the video cables, that would be a real epoch.

We found that the cabling behind the AP table is still quite ugly....grurrrh

Attachment 1: IMG_2684.jpg
  3370   Thu Aug 5 22:36:11 2010 KojiUpdatePSLPSL preparation work

PSL preparation work

Aug 5th 10am-4pm?: (Kiwamu, Alberto, Koji)

  • Removing the unused cables around the PSL table and the control room

Aug 6th 10am-4pm?: (Kiwamu (ex. noon-2pm), Alberto, Koji, Jenne ('till noon) )

  • Labeling the cables to be disconnected / making the records ==> All
  • Removals
    • the big nuts at the side of the PSL table ==> Steve
    • the cable ties on the PSL frame ==> Easy
    • Innolight 2W ==> Kiwamu
    • the green pickoff optics at the edge, if necessary ==> Kiwamu talking with Steve
    • Optics on the shelf ==> Jenne / Koji
    • Oscilloscopes on the shelf ==> Jenne / Koji
    • CCD camera connections (optional, as far as not critical for the operation)
  • Put poles on the table (for the plastic sheet) ==> Alberto / Koji

Aug 9th  9am-5pm: (Steve, Jenne, Alberto, Koji)

  • Disconnecting the cables ==> All
  • Shutting down the PSL ==> Steve/Koji
    • Draining the cooling water  ==> Steve
  • Removals
    • The accelerometers ==> Jenne
    • the PSL chamber ==> Steve
    • Periscopes ==> Alberto
  • Sealing of the table with the plastic sheets


  • The chiller is planned to go to MIT


  3374   Fri Aug 6 12:33:10 2010 KojiUpdateIOOMode Cleaner WFS

 Yesterday , I put in the Output Matrix, and changed the gain sliders for the 4 WFS loops.

From how much to how much have you chnged the gain?

Next we stepped to putting in the gains for the MC2 oplev servo.

I like to put the credit to Aidan for teaching Nancy how to use FOTON.


This complete 6 * 6 model does work, and was able to keep the transmission held.

This should be in this size:

This complete 6 * 6 model does work,
and was able to keep the transmission held.


  3375   Fri Aug 6 12:44:29 2010 KojiUpdateIOOMC data taking over the weekend


Do you like to keep the WFS turned on?

This may change the transfer functions between the ground motion to the angle time by time,
and thus change the TF between the GND and the MCL.


Nancy has the Mode Cleaner for her work for the night, and is going to leave the MC happy, locked, autolocker on, WFS enabled, the works, and write down in the elog the time that she's finished. After that, I'm taking MC/seismic data all weekend long.  During the weekend, if at all possible, please don't go into the IFO room, especially near the Mode Cleaner.  If you do need to go into the IFO room, please elog the time you went in, and the time you left so I can correlate it with my dataThis is actually important, so please stick a quick elog entry in if you even think about opening the doors to the IFO room. It is much appreciated. 


  3381   Fri Aug 6 20:00:03 2010 KojiUpdatePSLPSL preparation work

PSL preparation work report

Aug 6th 10am-5pm: (Steve, Jenne, Alberto, Kiwamu, Koji)

- We labeled the cables to be disconnected

  • These will be disconnected in order to isolate the PSL table and the frame (housing) from the other part of the lab.
  • Upon the labeling we made the list and the map of the cables to be removed.
  • On Monday we disconnect those cables one by one accoding to the list.

- The following stuffs have been removed from the PSL table

  • The big nuts at the side of the PSL table
  • The cable ties on the PSL frame
  • Innolight 2W
  • The green pickoff optics at the edge
  • The optics on the shelf
  • The oscilloscopes on the shelf

- The OMC power supply cable was visited.

  • The connections to the power supply were removed. There are two HV outputs.

- We put thick and long optical poles

  • They are placed at the edge of the table so that we can put the plastic sheets on the table without touching the optics.

Plan on Monday

Aug 9th  9am-5pm: (Steve, Jenne, Alberto, Koji)

  • Disconnecting the cables ==> All
  • Shutting down the PSL ==> Steve/Koji
    • Draining the cooling water  ==> Steve
  • Removals
    • The accelerometers ==> Jenne
    • The reference cavity chamber ==> Steve
    • The small periscope ==> Alberto
  • Sealing of the table with the plastic sheets
  • The chiller is planned to go to MIT 


Attachment 1: PSL_cable_map.pdf
PSL_cable_map.pdf PSL_cable_map.pdf
  3382   Sat Aug 7 10:47:38 2010 KojiSummaryelogelog restarted / source of the trouble eliminated

Nancy notified me that the elog crashed. It was fixed.

I restarted elog, but it kept crashing. Some of the entries on Aug 6th caused the trouble.

I tried to refresh the pictures in entries 3376, 3377, 3378. Still it kept crashing.
I started to dig into the elog file itself. (/cvs/cds/caltech/elog/elog-2.7.5/logbooks/40m/100806a.log)

FInally I found that there was some invalid reply links in the entry 3379.

Date: Fri, 06 Aug 2010 19:29:59 -0700
Reply to: 3379
In reply to: 3379

The entry is refering this entry itself. That is weird. So I deleted the reply-to and in-reply-to lines.
Then elogd got happy.

In fact, 3379 was a dupulication of 3380, so I deleted this entry.

  3383   Sat Aug 7 11:07:44 2010 KojiConfigurationPSLMC kept locked / PMC control gain reduced to +13dB

Jenne asked us to keep th MC locked and let the seismometers happy through this weekend.
Note that the work at the control room and the desks are no problem as far as you are quiet.

Nancy told Jenne and me that she finished the work and reverted the WFS to the old state at 4:30AM.
She could not make the elog as it has been crashed.

MC and old MC WFS looks working as usual.

From 6:40AM to 9:40AM the oscillation of the PMC looks present.

At 10:30AM I reduced the gain of the PMC from +15dB to +13dB.

  3388   Mon Aug 9 15:54:43 2010 KojiUpdateIOOMode Cleaner ASC

The WFS and QPD servos were working. That was great.
Everything was fine except for the time series plots.

I could not get what story you are telling with the time series.
(e.g. your's are good or bad or anything)

  3391   Tue Aug 10 05:56:07 2010 KojiUpdatePSLPSL Table Lifting Preparation

Work on Aug 9th

Steve, Jenne, Koji, Alberto, Aidan, Jan, Sharmila, Katherine

From 9am to 6pm

  • Shutting down the PSL after the 90885 hours of service
  • Removals
    • The accelerometers
    • The reference cavity chamber
    • The periscopes were left so far
  • The cables between the PSL table and the outside have been disconnected
    • Listed items on Friday
    • Some unlisted items recorded and disconnected
    • Drained the cooling water from the chiller lines
    • Pulled out the chiller connections at the control room as well as the chiller control cables (temp sens & RS232C)
  • Sealed the PSL table with plastic sheets
    • Put antistatic films to the table (they are supported by the long optical poles)
    • Used capton tapes to fix the films on to the table
    • Put the white huge plastic sheet to cover the table at once
    • Some spaces at the edge of the tables are left flat such that the C-clamps can be attached
  • Sealed the AP and the ITMY tables by capton tapes

Some photos are attached in this entry. All of the photos found in the picasa album (click the slideshow)

Attachment 1: IMG_2686.jpg
Attachment 2: IMG_2691.jpg
Attachment 3: IMG_2692.jpg
Attachment 4: IMG_2711.jpg
  3395   Tue Aug 10 22:40:55 2010 KojiSummaryPEMAccelerometer located on and below the PSL table

Result of the accelerometer measurement


We wanted to characterize the PSL table before the work before its lifting up.
We put a set of three-axis Wilcoxon accelerometers on the ground and another set on the PSL table through the weekend.


- The data at 9th Aug 00:00(UTC) is used. This was Sunday 5PM in the local time.
- The freq resolution was 0.01Hz. The # of avg was 50.

- The accelerometer signals were calibrated by the value 1.2e-7 V/(m/s^2). We use this absolute value of the spectrum for the comparison purpose.

- The accelerometers were aligned to North(X), East(Y), and Up(Z). There was the coherence observed from 2~20Hz.
  The transfer functions are valid only this frequency region although we still can set the lower bound of them.

- The transfer functions in the horizontal directions show huge peaks at around 20Hz. The Q of the peaks are ~30 to ~100.
  The vertical transfer function shows somewhat lower peak at around 50Hz with Q of ~10.

Some thoughts

- The low resonant freq and the high Q of the horizontal mode comes from the heaviness of the table.

- We are going to raise the table. This will usually mean that we get the lower resonant freq. This is not nice.

- So, the decision to use 6 tripods rather than 4 was right.
- The steel tripods are expected to give both more rigidity and more damping than the chep-looking hollow Newport legs.
- Concrete grouting of the tripods will also lower the effective height and will benefit for us.


Attachment 1: PEM_100809.pdf
  3403   Wed Aug 11 16:56:00 2010 KojiSummaryEnvironmentCovering of the IFO

Katharine, Sharmila, Gopal, Kiwamu, Jenne, Aidan, Steve, and Koji

A guy from the carpenter shop has done the drilling work in the morning.

In the afternoon we wrapped the central part of the interferometer with plastic sheets in order to avoid the dusts from the tile ripping that will happen tomorrow.

Attachment 1: IMG_2732.jpg
  3412   Thu Aug 12 17:10:07 2010 KojiUpdatePhase CameraSideband power measurement (updated)

This sounds very relieving although this could be a lower bound of the number.
Why didn't you use the output on the PD which just give us the direct observation of your so-called SCR.

Ed: I meant time series of the PD output


So the SCR is calculated by the ratio of the FFT'd DC and the 5 Hz signal. Using the CCD, I obtained the SCR to be 0.075 ± 0.01. Previously, we expected our SCR to be 0.09 as in the previous e-log entry. 


  3487   Mon Aug 30 13:57:25 2010 KojiSummaryPSLPSL table vibrational performance after the upgrade

Jenne and Koji

Last week Jenne has put the accelerometers on and under the PSL table immediately after the plastic sheets were removed.

So I took the same measurement as I did on 9th Aug.

Here is the comparison of the vibrational performance of the table before and after the modification.

Basically the table is now stiffer and more damped than it was before.
We don't find any eminent structure below (at least) 70Hz.

This result is obtained despite elevating of the table.

1) Attachment 1

For the horizontal comparison (top),  it is clearly seen that the large resonant peak at 20Hz was eliminated.
At least the new resonances went up to 70-90Hz region. Y is basically equivalent to X.

For the vertical comparison (bottom), it is clearly seen that the resonant peaks at around 50 & 70Hz were eliminated. 
At least no new resonance is seen.

2) Attachment 2

All-in-one plot for the measurement --- spectra, coherences, transfer functions --- after the upgrade. I put the same plot for the one before the upgrade.

Attachment 1: PEM_100830_SPE.pdf
Attachment 2: PEM_100830.pdf
PEM_100830.pdf PEM_100830.pdf
  3502   Wed Sep 1 08:28:43 2010 KojiUpdatePSLPSL upgrade update

  1. We got the lenses from CVI for the mode matching, but not the metric screws for the laser mounting. I am tempted to tap holes in the laser base.

I am feeling that it is ok to carefully make new holes and threads as far as the holes do not penetrate the plate.
The thickness of the plate can be measured by the four holes at the corners.


  3503   Wed Sep 1 08:36:59 2010 KojiHowToPSL2W NPRO Mount designed with emachineshop.com software

1. I can not see whether the attaching surface is flat or not.
It should have ~1mm step to avoid "the legs" of the laser at the four corners.
Otherwise we will have ~0.5mm space between the block and the laser
and will squish this gap by the screws => cause the deformation of the block and the laser.

2. The countersinks for the M4 screws can be much deeper so that we can use the existing M4 screws.
In any case, the long M4 screws are not rigid and also not common.


To test out this website - emachineshop.com, Jenne and I are designing some of the mounts for the new beam height.


It took me a few hours to figure out how to do it, but the software is easy enough for simple stuff. This is a brass mount with M4 clearance holes which are countersunk and a lip so that it can be dogged down to the table.


  3522   Fri Sep 3 13:04:30 2010 KojiFrogsElectronicsCable cutting tools

Yeah, this looks nice.

And I also like to have something I have attached. This is "HOZAN P-90", but we should investigate American ones
so that we can cut the wires classified by AWG.


I found this very interesting German maker of cool cable cutting tools. It's called Jokari.

We should keep it as a reference for the future if we want to buy something like that, ie RF coax cable cutting knives.



Attachment 1: P90.jpg
  3527   Mon Sep 6 20:38:58 2010 KojiUpdateCDSSusension model reviewed

I have reviewed the suspension model of C1SUS and refined it.

It is comaptible to the current one but has minor additions.

Attachment 1: suspension_model.pdf
  3575   Wed Sep 15 03:08:26 2010 KojiUpdatePSLFSS locking

Brilliant! This is the VERY way how the things are to be conquered!


The RefCav is locked and aligned. I changed the fast gain sign by changing the jumper setting on the TTFSS board. The RefCav visibility is 70%. The FSS loop ugf is about 80 kHz (plot attached)  with FSS common gain max out at 30 dB. There is about 50 mW coming out of the laser and a few mW going to RefCav out of the back of the PMC. So the ugf can be made higher at full power. I have not made any changes to account for the PMC pole (the FSS is after the PMC now). The FSS fast gain was also maxed out at 30 dB to account for the factor of 5 smaller PZT actuation coefficient - it used to be 16 dB according to the (previous) snap shot. The RefCav TRANS PD and camera are aligned. I tuned up the phase of the error signal by putting cables in the LO and PD paths. The maximum response of the mixer output to the fast actuator sweep of the fringe was with about 2 feet of extra cable in the PD leg.

I am leaving the FSS unlocked for the night in case it will start oscillating as the phase margin is not good at this ugf.


  3581   Fri Sep 17 03:06:06 2010 KojiUpdateSUSSOS sent for baking

Two SOS suspensions for the ETMs were disassembled and packed for cleaning and baking by Bob.

These suspensions have been stored on the X end flow bench long years, and looked quite old.

They have some differences to the modern SOSs.

- The top suspension block is made of aluminum and had dog clamps to fix the wires.
- The side bars are not symmetric: the side OSEM can only be fixed at the right bar (left side in the picture).
- EQ stops were made of Viton.
- One of the tower bases seems to have finger prints (of Mike Zucker?).

I found that the OSEM plates had no play. We know that the arrangement of the OSEMs gets quite difficult
in this situation. Therefore the holes of the screws were drilled with the larger drill.

We decided to replace all of the screws to the new ones as all of the screws are Ag plated and got corroded
by silver sulfide (Ag2S). I checked our stock in the clean room. We have enough screws.

Important note: Use stainless screws in aluminum / Silver-plated screws in stainless
There exists some study about galling: LIGO-G020394-00-D

Attachment 1: IMG_3596.jpg
Attachment 2: IMG_3597.jpg
  3582   Fri Sep 17 03:32:11 2010 KojiUpdateSUSArrangement of the SUS towers

The day before yesterday, I was cleaning a flow bench in the clean room.

I found that one SOS was standing there. It is the SRM suspension.

I thought of the nice idea:

- The installed PRM is actually the SRM (SRMU04). It is 2nd best SRM but not so diiferent form the best one.
==> Use this as the final SRM

- The SRM tower at the clean room
==> Use this as the final PRM tower.
==> The mirror (SRMU03) will be stored in a cabinet.

- The two SOS towers will be baked soon
==> Use them for the ETMs

This reduces the unnecessary maneuver of the suspension towers.

  3595   Wed Sep 22 22:22:12 2010 KojiConfigurationComputersNetgear Network Switch fan broken.

Net switch mumbo-jumbo:

Although Rana is going to buy a replacement for the Netgear Switch for martian, I opened the lid of the Netgear as the fan already have stopped working.
Also the lid of the other network switch for GC (Black one) was opened as it has a broken fan and a noisy half-broken fan.

I have asked Steve to buy replacement fans. These would also be the replacement of the replacement.

During the work, it seemed that I accidentally toggled the power supply of linux1. It lead lengthy fsck of the storage.
This is why all of the machines which rely on linux1 got freezed. linux1 is back and the machines looked happy now.

If you find any machine disconnected from the network, please consult with me.


The Netgear Network Switch in the top shelf of Nodus' rack has a broken fan. It is the one interfaced to the Martian network.

The fan must have broken and it is has now started to produce a loud noise. It's like a truck was parked in the room with the engine running.

Also the other network switch, just below the Netgear, has one of its two fans broken. It is the one interfaced with the General Computer Side.

I tried to knock them to make the noise stop, but nothing happened.

We should consider trying to fix them. Although that would mean disconnecting all the computers.


  3597   Thu Sep 23 02:45:30 2010 KojiSummaryComputersnodus gracefully rebooted

Zach> Nodus seemed to be working fine again, and I was browsing the elog with no
Zach> problem. I tried making an entry, but when I started uploading a file it
Zach> became unresponsive. Tried SSHing, but I get no prompt after the welcome
Zach> blurb. ^C gives me some kind of tcsh prompt (">"), which only really
Zach> responds to ^D (logout). Don't know what else to do, but I assume someone
Zach> knows what's going on.

By gracefully rebooting nodus, the problem was solved.

It (">") actually was the tcsh prompt, but any commands with the shared or dynamic link libraries looked unfunctional.

I could use
    cd /.../...
    echo *
to browse the directory tree. The main mounted file systems like /, /usr, /var, /cvs/cds/caltech looked fine.
I was afraid that the important library files were damaged.

I tried
in order to flush the file systems.
These should run even without the libraries as mount must properly work even before /usr is mounted.

They indeed did something to the system. Once I re-launch a new login shell, the prompt was still ">"
but now I could use most of the commands.

I have rebooted by usual sudo-ing and now the services on nodus are back to the functional state again.

# nodus was working in the evening at around 9pm. I even made an e-log entry about that.
# So I like to assume this is not directly related to the linux1 incident. Something else could have happened.

  3599   Thu Sep 23 11:15:20 2010 KojiFrogsComputersnodus gracefully rebooted

svn is back after starting apache on nodus.



SVN down

mafalda down

I am guessing that the NFS file system hangup may have caused some machines to get into an awkward state. We may be best off doing a controlled power cycle of everything...


  3601   Thu Sep 23 13:16:57 2010 KojiFrogsComputersnodus gracefully rebooted

mafalda is up now.

I found that the cable for mafalda (the sole red cable) had a broken latch.
The cable was about falling off from the switch. As a first-aid, I used this technique to put a new latch, and put it into the switch.

Now I can logged in it. I did not rebooted it.


SVN down

mafalda down

I am guessing that the NFS file system hangup may have caused some machines to get into an awkward state. We may be best off doing a controlled power cycle of everything...


  3608   Sat Sep 25 19:01:13 2010 KojiUpdateElectronicstesting TTFSS

How much current do you need for each voltages?

GE-82 was the only PNP transister I could find in the lab. It's too old but we just like to confirm any other components are still functioning.

Similarly, we can confirm the functionality of the other components by skipping those current boost transisters,
if we don't need more than 30mA.


  3669   Thu Oct 7 15:05:46 2010 KojiUpdatePSLmeasured PMC's laser power-output relation

It was a bit difficult to comprehend the result.
Is it good? or bad? Have you seen the thermal effect? or not?

- Put linear lines to show the visibility of the cavity.

- Calibrate the incident power and make another plot to show the visibility (%) vs the incident power (W).


(Rana, Yuta)


 We wanted to see thermal effects on the PMC.

What I did yesterday:
 Changed the current of the NPRO from 2A to 0.8A and measured the power of the reflected/transmitted light from the PMC when locked.
 I also measured the power of the reflected light when PMC is not locked (It supposed to be proportional to the output power of the laser).

 Attached. Hmmmm......
 At several points of the laser current, I could'nt lock the PMC very well. The power of the reflected/transmitted light depend on the offset voltage of the PZT.
 When the laser power was weak(~<0.9A), the power of reflected/transmitted light changed periodically(~ several minutes).


  3671   Thu Oct 7 16:21:02 2010 KojiOmnistructureCDSBig 3

Both Rolf and Alex (at least his elbow) together visited the 40m to talk with Joe for the CDS.

40m is the true front line of the CDS development!!!

Attachment 1: IMG_3642.jpg
  3683   Sun Oct 10 16:44:59 2010 KojiOmnistructurePhotosKepco Tube HV supply
Attachment 1: IMG_3637.jpg
Attachment 2: IMG_3640.jpg
  3684   Sun Oct 10 16:59:20 2010 KojiOmnistructureCOCPRM phase map measurement at Downs SB 014

[Kiwamu, Yuta, Koji]

We went to the new metrology lab at Downs subbasement (Rm014) in order to measure the phase map of the delivered PRMs.

It's brand-new. So we had to measure the reference phase map, calibration as well as the phase map of our mirrors (3 PRMs and 1 spare SRM). It took a whole day...

Attachment 1: IMG_3646.jpg
Attachment 2: IMG_3647.jpg
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