40m QIL Cryo_Lab CTN SUS_Lab TCS_Lab OMC_Lab CRIME_Lab FEA ENG_Labs OptContFac Mariner WBEEShop
 40m Log, Page 51 of 344 Not logged in
ID Date Author Type Category Subject
4936   Mon Jul 4 14:27:35 2011 kiwamuSummaryGeneralWeekly report

Summary of the week ending July 3rd.  Number of elog entries = 44

# - SUS

* The output TO_COIL matrix were simplified
* Checked all the BO whitening switch => Only ITMY_UL didn't switch
* All the DOF filters were normalized.
=> All the DOF filters are now ("3:0.0", "Cheby", "BounceRoll")
=> The High pass should have 30Hz cut off ("30:0.0") ?
* All the resonant peaks has been fit

# - LSC

* MICH noise budget.
=> dominated by sensing noise.
* The sensing matrix in the PRMI configuration was measured.
=> The demodulation phase on AS55 seemed wrong. Need a doublecheck
* A new screen, called C1LSC_OVERVIEW.adl, was released.

* A channel name modification: "PRC" and "SRC" => "PRCL" and "SRCL" and etc.
* The response of the LSC whitening filters were checked.
=> CH26 showed different phase response.

# - MC work

* Power budget on the AP table was made (in a high power situation).
REFL11 = 7.4 mW
REFL55 = 22 mW
MCREFL = 114 mW
WFS1   = 1.24 mW
WFS2   = 2.7 mW
* Measurement and adjustment of RFQPD response
Resonance frequencies of WFS1 and WFS2 were adjusted. WFS1 and WFS2 were installed on the AP table
* Started working on MCL path.
=> needs some more CDS jobs to correctly assign ADC channels

# - CDS

* Joe modified the automated scripts for producing model webviews

# - ABSL

* The alignment of the injection beam was done.

# - Fiber experiment

* A fiber was laid down from the ETMY table to the PSL table

# - TT characterization

* The mechanical stage for the horizontal displacement measurements is set up.

# - Configuration and other topics

* Maglev stuff has gone to bridge lab.
* Chris.W told us that the EPICS mutex issue can be solved by upgrading the EPICS version
* All the PDs are stored in the east arm cabinet E4
* Safety interlocks were connected to the ETMY laser and ABSL laser
* Cshrc.40m was modified to make 32-bit machine happy
* NDS2 buffer size on Mafalada had been too small and was increased somewhat such that we can still work for the SUS peak fit job

4950   Wed Jul 6 23:53:38 2011 kiwamuSummaryGeneralminutes of 40m meeting
Attachment 1: meeting.pdf
4951   Thu Jul 7 02:23:59 2011 JenneSummaryLSCLSC Whitening Filters have been fit

I have fit all of the LSC whitening filters using vectfit4.m

All the data is in my folder ..../users/jenne/LSC_WhiteningTest_29June2011/

The zpk info is saved with each plot of the fit.  The pdfs are kind of huge to stitch together (or rather my computer doesn't want to do it), so I'll just post a representative one for now.

During the daytime either tomorrow or Friday I'll adjust the actual dewhitening filters to match the measured zpk values.

4955   Thu Jul 7 15:34:44 2011 JenneSummaryLSCLSC Whitening Filters have been fit

 Quote: During the daytime either tomorrow or Friday I'll adjust the actual dewhitening filters to match the measured zpk values.

I made a handy-dandy table showing the zpk values for each whitening filter in the wiki: New whitening filter page

Next on the whitening filter to-do list: actually put these values into the dewhitening filters in foton.

4956   Fri Jul 8 09:53:49 2011 Nicole SummarySUSSummer Progress Report 1

A copy of my summer progress report 1 has been uploaded to ligodcc 7/711 and I have just added a copy to the TTsuspension wiki

PDF copy of Summer Progress Report

4969   Thu Jul 14 20:24:32 2011 NicoleSummarySUSPhotosensor Head Lessons

Today I tested the photosensor head combination (2 Hamamatsu S5971 photodiodes and 1 Hamamatsu L9337 LED). I discovered that I had burnt out the LED and the photodiodes when I soldered them to the PCB board.

After looking up soldering information on Hamamatsu photodiodes, I learned that I need to solder at least 2 mm away from the head. I checked the pins of my burnt-out photodiodes and I had soldered 1.5 mm away from the head. To prevent this problem from happening again, Suresh suggested that I clip a lead onto photodiode/LED pin while I solder on connections to help dissipate some of the heat.

Today I was able to get a single photodiode (not attached to the PCB) to measure light emitted from an LED and I observed how voltage fluctuated as I moved the photodiode around the LED.

Suresh and Jamie also helped me to fix my photosensor head design (to make it more electrically-stable). Originally, I had planned to solder the LED and photodiodes onto a PCB and to mount that PCB to the front of a small metal Pomona Electronics box (with a whole cut out for the photodiodes and LED) using spacers, screws, and nuts.  However, the PCB I am using to solder on the LED and photodiodes has metal connections that may cause problems for the LED and photodiodes lying on the surface. Now, the plan is to have the LED and photodiodes mounted to the PCB with an insulatory PCB in between. Below is an explanatory picture.  I will determine the placement of the LED and photodiodes after making screws holes in the two PCBs to attach to the metal face of the box. I want to attach the screw holes first to make sure that the PCBs (and attached photosensor) are centered.

4970   Fri Jul 15 01:11:21 2011 KojiSummarySUSPhotosensor Head Lessons

Rotate the PDs and the LED so that you can put them as close as possible.
This is to increase the sensitivity of the sensor. Think why the closer the better.

4971   Fri Jul 15 08:48:36 2011 JamieSummarySUSPhotosensor Head Lessons

Nicole: I thought we had decided to use teflon as the insulator between the PCB (yellow) and the LED/PDs?  I don't think you should use another circuit board with copper on it.  The copper will short the LED/PD heads to the metal box, which might be problematic.

Otherwise the design looks pretty good.  I think the PDs have three leads each, yes?

4974   Fri Jul 15 14:23:30 2011 NicoleSummarySUSPhotosensor Head Lessons

Ah! I see! Thank you!

I should put the LEDs and photodiodes closer together so that more of the reflected light falls on the photodiodes and the photodiodes have a higher response.

Also the reflectivity of the mirror will be optimized if the incident light is normal to the mirror surface. We will be setting up the photosensor and mirror so that the LEDs

emit light normal to the mirror surfaceDuring displacement, this light may be slightly off-normal but still close to normal incidence. We want the photodiodes to be close to the LED since we want

them to detect light that is close to the path of normal incidence (small angles of reflection). [Thanks to Jenne for helping me figure this one out!]

Thank you for the suggestion ^___^

4975   Fri Jul 15 14:29:30 2011 NicoleSummarySUSPhotosensor Head Lessons

You are right Jamie! Thank you for the correction! I will now use the Teflon sheet instead of the PCB piece.

The photodiodes do have three legs, but I imagined the third one lying on a different plane, since it is spaced apart from the two I have drawn.

I should include this third leg in my drawing?

5000   Wed Jul 20 12:05:08 2011 NicoleSummarySUSWeekly Summary

Since last week Wednesday, I have since found a Pomona Electronics box (thanks to Jenne)

to use for my photosensor head circuit (to house the LED and 2 photodiodes). Suresh has

shown me how to use the 9-pin Dsub connector punch, and I have punched a hole in this box

to attach the Dsub connector.

Since this past entry regarding my mechanical design for the photosensor head (Photosensor Head Lessons),

I have modified the design to use a Teflon sheet instead of a copper PCB and I have moved the LED

and photodiodes closer together, upon the suggestions of Jamie and Koji.  The distance between

components is now 0.112" instead of the initial 0.28".  Last night, I cut the PCB board for the LED

and photodiodes and I drilled holes onto the PCB board and Teflon sheet so that the two may be

mounted to the metal plate face of the Pomona box.  I still need to cut the viewer hole for and

drill screws into the face plate.

I have also been attempting to debug my photosensor circuit (box and LED/photodiode combination).

Since this last entry (Painful Votlage Regulator and Circuit Lessons), Suresh has helped me to get the parts

that I need from the Downs Electronics lab (15 wire ribbon cable, two 9 pin D-sub connectors M,

one 15 pin D-sub connector M, one 16 pin IDC connector). Upon the suggestion of Jamie, I have

also made additional safety changes to the circuit by fixing some of the soldering connections

so that all connections are done with wires (I had a few immediate lines connected with solder).

I believe the the photosensor circuit box is finally ready for testing. I may just need some help

attaching the IDC connector to the ribbon cable. After this, I would like to resume SAFELY

testing my circuit.

I have also been exploring SimMechanics. Unfortunately, I haven't been able to run the

inverted pendulum model by Sekiguchi Takanori. Everytime I attempt to run it, it says

there is an error and it shuts down Matlab. In the meanwhile, I have been watching

SimMechanics demos and trying to understand how to build a model. I'm thinking that

maybe once I figure out how SimMechanics works, I can use the image of his model

(I can see the model but it will not run) to construct a similar one that will hopefully work.

I have also been attempting to figure out the circuitry for the pre-assembled

accelerometer (made with the LIS3106AL chip).  I have been trying to use a multi-meter

to figure out what the components are (beyond the accelerometer chip, which I have

printed out the datasheet for), but have been unsuccessful at that. I have figured out

that the small 5 pin chip says LAMR and is a voltage regulator. I am hoping that if I can

find the data sheet for this voltage regulator, I can figure out the circuitry. Unfortunately,

I cannot find any datasheets for a LAMR voltage regulator. There is one by LAMAR, but

the ones I have seen are all much larger. Does anyone know what the miniature voltage

regulator below is called and if "LAMR" is short for "LAMAR"?

5003   Wed Jul 20 18:44:54 2011 KojiSummarySUSWeekly Summary

5022   Sun Jul 24 20:36:03 2011 haixingSummaryElectronicsAA filter tolerance analysis

Koji and Haixing,

We did a tolerance analysis to specify the conner frequency for passive low-pass filtering in the AA filter of Cymac. The
link to the wiki page for the AA filter goes as follows (one can have a look at the simple schematics):
http://blue.ligo-wa.caltech.edu:8000/40m/Electronics/BNC_Whitening_AA

Basically, we want to add the following passive low-pass filter (boxed) before connecting to the instrumentation amplifier:

Suppose (i) we have 10% error in the capacitor value and (ii) we want to have common-mode rejection
error to be smaller than 0.1% at low frequencies (up to the sampling frequency 64kHz), what would be
conner frequency, or equivalently the values for the capacitor and resistor, for the low-pass filter?

Given the transfer function for this low-pass filter:

and the error propagation equation for its magnitude:

we found that the conner frequency needs to be around 640kHz in order to have
with

5023   Sun Jul 24 20:47:21 2011 ranaSummaryElectronicsAA filter tolerance analysis

This is sort of OK, except the capacitor connects across the (+) terminals of the two input opamps, and does not connect to ground.

Also, we don't care about the CMRR at 64 kHz. We care about it at up to 10 kHz, but not above. The sample frequency of the ADC is 64 kHz, but all of the models run at 16 kHz or less, so the Nyquist frequency is 8 kHz.

And doesn't the value depend on the resistors?

5024   Sun Jul 24 22:19:19 2011 haixingSummaryElectronicsAA filter tolerance analysis

>> This sort of OK, except the capacitor connects across the (+) terminals of the two input opamps, and does not connect to ground:

>> Also, we don't care about the CMRR at 64 kHz. We care about it at up to 10 kHz, but not above.

In this case, the conner frequency for the low-pass filter would be around 100kHz in order to satisfy the requirement.

>>And doesn't the value depend on the resistors?

Yes, it does. The error in the resistor (typically 0.1%)  is much smaller than that of the capacitor (10%). Since the resistor error propagates in the same as the capacitor,
we can ignore it.

Note that we only specify the conner frequency (=1/RC) instead of R and C specifically from the tolerance analysis, we still need to choose appropriate
values for R and C with the conner frequency fixed to be around 100kHz, for which we need to consider the output impedance of port 1 and port 2.

5026   Mon Jul 25 11:02:19 2011 kiwamuSummaryGeneralWeekly report

Summary of the week ending July 10th.  Number of elog entries = 21

# - SUS

+ The cutoff frequency of the high pass filters for the damping were set to 30Hz.
+ Turned off all the BounceRoll filters.
+ The BS oplev was checked and seemed healthy.

# - LSC

+ All the measred data of the LSC whitening filters were fit.
+ All the zpk parameters are recorded on the wiki.

# - ABSL

+ The setup completed.
+ The freqeucy-lock of the ABSL laser was achieved with UGF of ~ 40kHz.
+ The temperature of the ABSL laser was adjusted to be 47.25 deg

# - ALS

(Fiber experiment)
+ The I-P curve of the ETMY laser was measred.
+ The current set point is 1.8 [A], which used to be 1.5 [A], corresponding to the output of power of 197 [mW] and 390 [mW] respectively.

5027   Mon Jul 25 11:04:22 2011 kiwamuSummaryGeneralWeekly report

Summary of the week ending July 17th.  Number of elog entries = 20

- LSC
* BO switching logic for the WF was installed on c1lsc
* Channel mapping updated

- SUS
* Oplev health check. Spectrum of each quadrant on every suspension was inspected and looked healthy.

- OAF
* BNS interface board was attached to an AA board
* The AA board was installed on 1X7. The Electro-optic fanout chassis on 1X7 is now sitting on a jack, this should be fixed.

- Fiber experiment (ALS)
* Fibre from the ETMX and EMTY tables were routed to the PSL table

- Misc.
* Alberto came over to the 40m with Wagonga

5028   Mon Jul 25 11:06:38 2011 kiwamuSummaryGeneralWeekly report

Summary of the week ending July 24th.  Number of elog entries = 45

- LSC
* Check of LSC WF switching
-> some were switching, but the majority were not.

- SUS
* Ran activateDQ.py for seeting some DQ channels of Oplevs
* Turned ON all the offset buttons on the OL1, etc.
* Rebuilt and restarted c1msc, c1sus, c1scx and c1scy as an update.
* ETMY's shadow sensors look bad. Unknown noise below 3 Hz, which is higher than the usual floor by factor of 10.

- ABSL
* The frequency lock was down.
* The laser power into the RFPD had been too big, so it was reduced

- OAF
* Seismometers were connected to the AA-board on 1X6
* Most of the channels were acquired to the ADC, but some were not.

- Mode Cleaner
* Gain of quadrants were checked.
* Due to the SUS model update, the MC locking trigger hasn't worked correctly. This was fixed by changing ioo.db file

- Misc.
* Virtual box was installed on Rossa. Altium is now available on Rossa.

5038   Tue Jul 26 21:11:40 2011 haixingSummaryElectronicsAA filter tolerance analysis

Given this new setup, we realized that the previous tolerance analysis is incorrect. Because the uncertainty in the capacitance value
does not affect the common mode rejection, as two paths share the same capacitor. Now only the imbalance of two resistors is relevant.
The error propagation formula goes as follows:

We require that the common-mode rejection error at low frequency up to 8kHz, namely
with , one can easily find out that the corner frequency needs to be around 24kHz.

5044   Wed Jul 27 12:19:19 2011 NicoleSummarySUSWeekly Summary

Since last week, I've been working on building the photosensor head and have been making adjustments to my photosensor circuit box.

Changes to photosensor circuit (for box):

1) Last week, I was reading in the two signals from the two heads through a single input. Now there are two separate inputs for the two separate photosensors

2)During one of my many voltage regulator replacements, I apparently used a 7915 voltage regulator instead of a 7805 (thanks, Koji, for pointing that out! I never would have caught that mistake X___X)

3)I was powering my 5V voltage regulator with 10V...Now I'm using 15 V (now I only need 1 power supply and 3 voltage input plugs)

I have also began assembling my first photosensor head. Here is what I have so far:

Here is what needs to be done still for the photosensor head

I need to find four Teflon washers and nuts to rigidly attach the isolated PCB (PCB, Teflon sheet combination) to the box. I already have the plastic screws in (I want to use plastic and Teflon for electrical isolation purposes, so as to not short my circuit).

I need to attach the sheath of my signal cable to the box of the photosensor head for noise reduction (plan: drill screw into photosensor head box to wrap sheath wires around)

I need to attach the D-sub to the other end of my signal cable so that it can connect to the circuit box. So far, I only have the D-sub to connect the cable to my photosensor head

Yesterday, Suresh helped to walk me through the photosensor box circuit so that I now understand what voltages to expect for my circuit box trouble-shooting. After this lesson, we figured out that the problem with my photosensor box was that the two op-amps were saturated (so I fixed the feedback!). After replacing the resistor, I got the LED to light up! I still had problems reading the voltage signals from the photodiodes. I was reading 13.5V from the op amp output, but Koji explained to me that this meant that I was too close to saturation (the photodiodes were perhaps producing too much photocurrent, bringing the output close to saturation). I switched the 150 K resistor in the feedback loop to a 3.4K resistor and have thus successfully gotten displacement-dependent voltage outputs (i.e. the voltage output fluctuates as I move my hand closer and farther from the photosensor head).

Now that I have a successful circuit to power and read outputs from one photosensor, I can begin working on the other half of the circuit to power the other photosensor!

5045   Wed Jul 27 12:31:47 2011 Manuel, IshwitaSummaryPEMWeekly summary

We tested the seismometer last friday

Jan came and tested again the seismometer last monday

We wrote a simulation of the stacks transfer functions, and of the distance between the mirrors.

5046   Wed Jul 27 15:18:50 2011 kiwamuSummaryGeneralschedule

The vent will start from 1 st of August ! !

5048   Wed Jul 27 15:42:41 2011 kiwamuSummaryGeneralmitues of 40m meeting : Task list

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

++++ Task List for the vent preparation ++++

+ Preparation of beam dumps (Jamie / Steve)

+ Health check of shadow sensor and measurement of the cross-coupling  (Steve)

+ Measurement of the arm Lengths and estimation of the required precision (Kiwamu)

+ Alignment of the Y green beam (Suresh)

+ Alignment of the incident beam axis (Jenne)

+ Measurement of the MC spot positions  (Suresh)

+ Loss measurement of the arm cavities (Kiwamu / volunteers)

++++ Task List for the post-vent activity ++++

+ 3f RFPDs (Koji / Rana)

+ EOM resonant circuit (Kiwamu)

+ Sophistication of the LSC model (Yoichi)

+ DRMI commissioning (Keiko / Anamaria)

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.

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 !

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.

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

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

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
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.

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.

5120   Fri Aug 5 02:00:09 2011 kiwamuSummaryGeneralsummary of today's invac work

[Jamie, Jenne, Suresh, Steve, Koji, Kiwamu]

We got two green beams coming out from the chambers !

Summary of today's invac work :

- removed the access connector and the BS north door

- realigned the X and Y arm to the green beams.

- installed a HWP on the ETMY table to rotate the polarization of the green beam to P.

- repositioned the first periscope on the BS table.

- repositioned the second periscope on the IOO table.

- steered some green mirrors on the IOO and OMC chamber to let the Y green beam come out to the PSL table.

- installed a PBS in front of the first periscope to spatially overwrap two green beams.

- adjusted the incident angle of the PBS to maximize the power of the Y green beam, which is transmitted through it.

- steer two mirrors on the BS table to align the X green beam

- installed two beam dumps, one is near the PBS to eliminate a ghost in the X green beam, and the other is on the back side of IPPOS/ANG pick off window.

- closed the doors.

Some Notes:

When steering the final green mirror on the OMC table, accidentally we changed the alignment of the MC incident mirror.

So the alignment of the incident beam going into MC has changed, and we haven't re-aligned it yet.

During we were installing the PBS on the BS table, we found that the allowable incident angle for the Y beam is about ~ 55 deg, which maximizes the amount of the transmitted Y green.

Since the PBS had been considered to be 45 deg incident in our optical layout, this required several modifications in the green mirrors.

To have a clear X green beam path going into the PBS, we had to slide the PBS and periscope to the West.

The periscope is now sitting on the very edge of the BS table, and in fact ~ 20% of the bottom plate of the periscope is already sticking out.

Also since 30% of the area of the PBS's post is on a hole, which is somehow for the stack, we had to use three dog clamps instead of a folk clamps to make the contact tight.

5122   Fri Aug 5 08:08:42 2011 kiwamuSummaryGeneralplan today

Today's main mission is : adjustment of the arm length

+ Open the ETMX(Y) door, starting from 9:00 AM

+ Secure the ETMX(Y) test mass by tightening the earthquake stops.

+ Move the ETMX(Y) suspension closer to the door side

+ Inspect the OSEMs and take pictures before and after touching the OSEMs.

+ Level the table

+ Move the ETMX(Y) suspension to have designed X(Y)arm length

+ Level the table again

+ Align the ETMX(Y) such that the green beam resonate

5127   Fri Aug 5 20:37:34 2011 jamieSummaryGeneralSummary of today's in-vacuum work

[Jamie, Suresh, Jenne, Koji, Kiwamu]

After this morning's hiccup with the east end crane, we decided to go ahead with work on ETMX.

Took pictures of the OSEM assemblies, we laid down rails to mark expected new position of the suspension base.

Removed two steering mirrors and a windmill that were on the table but where not being used at all.

Clamped the test mass and moved the suspension to the edge of the table so that we could more easily work on repositioning the OSEMs.  Then leveled the table and released the TM.

Rotated each OSEM so that the parallel LED/PD holder plates were oriented in the vertical direction.  We did this in the hopes that this orientation would minimize SD -> POS coupling.

For each OSEM, we moved it through it's full range, as read out by the C1:SUS-ETMX_{UL,UR,LL,LR,SD}PDMon channels, and attempted to adjust the positions so that the read out was in the center of the range (the measured ranges, mid values, and ultimate positions will be noted in a follow-up post).  Once we were satisfied that all the OSEMs were in good positions, we photographed them all (pictures also to follow).

Re-clamped the TM and moved it into it's final position, using the rails as reference and a ruler to measure as precisely as possible :

ETMX position change: -0.2056 m = -20.56 cm = -8.09 in (away from vertex)

Rebalanced the table.

Repositioned the mirror for the ETMX face camera.

Released TM clamps.

Rechecked OSEM centering.

Unblocked the green beam, only to find that it was displaced horizontally on the test mass about half an inch to the west (-y).  Koji determined that this was because the green beam is incident on the TM at an angle due to the TM wedge.  This presents a problem, since the green beam can no longer be used as a reference for the arm cavity.  After some discussion we decided to go with the TM position as is, and to realign the green beam to the new position and relock the green beam to the new cavity.  We should be able to use the spot position of the green beam exiting the vacuum at the PSL table as the new reference.  If the green X beam exiting at the PSL table is severely displaced, we may decide to go back in and move ETMX to tweak the cavity alignment.

At this point we decided that we were done for the day.  Before closing up, we put a piece of foil with a hole in it in front of the the TM face, to use as an alignment aperture when Kiwamu does the green alignment.

Kiwamu will work on the green alignment over the weekend.  Assuming everything works out, we'll try the same procedure on ETMY on Monday.

5130   Sat Aug 6 03:10:05 2011 SureshSummaryGeneralSummary of today's in-vacuum work

The table below gives the OSEM positions as seen on the slow chanels C1:SUS-ETMX_{UL,UR,LL,LR,SD}PDMon

Note that the side OSEM has the fast channel (OUTPUT) available and we used that to locate it.

When we began work the OSEMs were photographed so that we have a record of their locations till now.  It was difficult to get accurate estimate of the magnet offset inside the OSEM we could not see the screen on the camera while clicking.  We then took some pictures after finishing the work. These are given below

The picture of the left is from before OSEMs were moved. It can be seen that OSEMs are rotated to make sure that the magnets avoid touching the teflon sheets which hold the shadow sensors.  The picture on the right shows the positions of the OSEMs after we adjusted their positions.  This time we kept the teflon sheets vertical as shown to minimise the coupling between the Side and Axial directions.

We needed to reposition them once again after we moved the tower to the center of the table.

Pictures with more detail will be posted to the wiki later.

5131   Sat Aug 6 13:38:02 2011 ranaSummaryGeneralSummary of today's in-vacuum work

This OSEM placement is just the OPPOSITE of what the proper placement is.

Usually, we want to put them in so that the LED beam is vertical. This makes the OSEM immune to the optic's vertical mode.

The orientation with the horizontal LED beam makes the immunity to the side mode better, but may spoil the vertical.

In reality, neither of these assumptions is quite right. The LED beam doesn't come out straight. That's why Osamu and I found that we have to put in some custom orientations.

Also, the magnet gluings relative to the OSEM bracket centers are not perfectly aligned. So...I am saying that the OSEMs have to be oriented empirically to reduce the couplings which we want to reduce.

5132   Sun Aug 7 11:10:54 2011 SureshSummaryGeneralOSEM positioning

 Quote: This OSEM placement is just the OPPOSITE of what the proper placement is. Usually, we want to put them in so that the LED beam is vertical. This makes the OSEM immune to the optic's vertical mode. The orientation with the horizontal LED beam makes the immunity to the side mode better, but may spoil the vertical. In reality, neither of these assumptions is quite right. The LED beam doesn't come out straight. That's why Osamu and I found that we have to put in some custom orientations. Also, the magnet gluings relative to the OSEM bracket centers are not perfectly aligned. So...I am saying that the OSEMs have to be oriented empirically to reduce the couplings which we want to reduce.

Kiwamu suggested that since the side resonance is at a lower frequency than the bounce (~17Hz)  we ought to worry about the side more than the bounce.  If this is okay we can reposition the OSEMs to minimise this coupling.

More over, in the current position, the OSEM s will not sense the side motion!!  So we definitely need to reposition them.  Sorry! I was being a spatz.

5145   Mon Aug 8 22:12:58 2011 NicoleSummarySUSDaily Summary

Today I balanced the mirror, finished putting together the second photosensor, and finished my photosensor circuit box!

Upon Jamie's suggestion, I have used a translation stage to obtain calibration data points (voltage outputs relative to displacement) for the new photosensor and for the first photosensor.

I will plot these tomorrow morning (too hungry now > < )

Here is a photo of the inside of my circuit box! It is finally done! It is now enclosed in a nice aluminum casing ^ ^

Attachment 1: frontview.jpg
5147   Tue Aug 9 02:03:16 2011 kiwamuSummarySUSsummary of today's work on ETMY

[Rana / Jenne / Kiwamu]

The ETMY suspension tower is currently sitting on the north side of the table for some inspections.

The adjustment of the OSEMs is ongoing.

(What we did)

+ Taken out two oplev mirrors, Jamie's windmill and a lemo patch panel.

+ Put some pieces of metal as makers for the original place

+ Put some makers on the distance of  dLY = -25.49 cm = -10.04 inch from the original place (see the 40m wiki).

The minus sign means it will move away from the vertex.

+ Brought the ETMY suspension tower to the north side to do some inspections

+ Did some inspections by taking the noise spectra (#5141)

+ Adjusted the OSEM range and brought the magnets on the center of the OSEM holders by rotating and translating the OSEMs

+ During the work we found the proper PIT and YAW gains were about -5, which are the opposite sign from what they used to be.

+ Trying to minimize the cross couplings

JD: There is still some funny business going on, like perhaps the LR magnet isn't quite in the OSEM beam.  We leave the optic free swinging, and will continue to investigate in the morning.

5151   Tue Aug 9 03:05:05 2011 kiwamuSummaryGeneralweekly report

Summary of the week ending Aug 8th.  Number of elog entries = 56

- VAC
+ The vent started Wednesday morning
+ Repositioning of the green periscopes and associated mirrors are done.
+ Got both of the green beams coming out from  the chambers
+ Moved the ETMX suspension tower by -8.09 inch (away from vertex)
+ Fixed the alignment of the ETMX CCD mirrors
+ Recovered the X green beam axis for the latest ETMX position

- SUS
+ oplev centered prior to the vent

- LSC
+ ETMY_TRANS_QPD didn't respond at all, needs to be fixed
+ Old MZ PD (InGaAs 2mm, @29.5MHz) has been modified for REFL33.
The 11MHz notch circuit is at the amp side instead of the diode side. This is ready for the installation
+ REFL165 PD has been made from the old 166MHz PD.

- IOO
+ IPPOS has been sick since 19th of July, 2011
+ IPANG is clipped on a pick-up mirror on the ETMY table. QPD itself is healthy.
+ The spot positions on the MC mirrors were measured prior to the vent.
The results are almost the same as before within a few percent difference expect for the MC2 yaw.
+ An attenuator, consisting of two HWPs and a PBS, has been installed on the PSL table for the MC low power state.
+ a 10% BS in front of the MCREFL_RFPD was replaced by a perfect reflector for the low power mode.
+ The incident power for MC was decreased to 20 mW
+ The beam axis going to MC was misalgned due to the attenutor.
Then the beam was aligned by touching two steering mirrors on the PSL table
+ MC is able to be locked in air. The reflection DC goes from 1.4 to 0.13 V when the MC is locked.

- ABSL
+ With the mass-kicking technique, the arm lengths were measured.
Xarm =  37.5918 m, Yarm = 37.5425 m.

- Green locking
+ Y green beam is aligned to the Y arm
+ Locking of the Y green is not robust, it needs to be revisited

- OAF
+ Wiener Filtering was applied on the data collected from the X-arm for a duration of 1500 seconds.

- Misc.
+ The hazardous waste people are moving chemicals around outside our door, and have roped off our regular front door.
+ The horizontal trolley drive of the east end crane stopped working. It will be fixed.

5154   Tue Aug 9 13:34:40 2011 NicoleSummarySUSNew Calibration Plots for Photosensors

Here are the new calibration plots for my photosensors. These calibrations were done using a translation stage.

The linear region for the first photosensor appears to be between 15.2mm and 30 mm

The linear region for the second photosensor appears to be between 12.7mm and 22.9mm

The slope for both is -0.32 V/mm  (more precisely, -0.3201 V/mm for PS 1 and -0.3195 V/mm for PS 2)

5160   Tue Aug 9 19:53:56 2011 NicoleSummarySUSWeekly Summary

This week, I have finished assembling everything I need to begin shaking. I built an intermediary mounting stage to mount the TT suspension base to the horizontal sliding platform, finished assembling the second photodiode, finished assembling the photosensor circuit box, and calibrated the two photosensors. Today I built a platform/stage to mount the photodiodes so that they are located close enough to the mirror/suspension that they can operate in the linear range.  Below is an image of the set-up.

The amplifer that Koji fixed is acting a bit strange again...It is sometimes shutting off (Apparently, it can only manage to do short runs ~ 1minute? That should be enough time?).

The set-up is ready to begin taking measurements.

5169   Wed Aug 10 12:32:09 2011 NicoleSummarySUSWeekly Summary Update

Last night, I attached a metal plate to the Vout faceplate of my photosensor circuit box because the BNC connection terminals were loose. This was Jamie's suggestion to establish a more secure connection (I had originally drilled holes for the BNCs that were much too large).

I have also fixed the mechancial set-up of my shaking experiment so that the horizontal sliding platform does not interfere with the photodiode mounting stage. Koji pointed out last night that in the full range of motion, the photodiode mounting stage interferes with the movement of the sliding platform when the platform is at its full range.

I have began shaking. I am getting a problem, as my voltage outputs are just appearing a high-frequency noise.

5170   Wed Aug 10 12:33:34 2011 Manuel, IshwitaSummaryPEMWeekly summary

We got the results of the wiener filtering simulations (Elog Entry)

We got the power spectra and coherence of the seismic noise measurements from GURALPs and STS seismometers (Elog Entry)

We tried to whiten the target and the input signal for the computation of the wiener filter for the real data, but the results are unsatisfactory. We should not care about high frequencies in wiener filter computation so we will just filter them off in the filter output with a low pass filter.

We just found the right gain for the system seismometer-AAboard-ADC (Elog Entry)

5178   Wed Aug 10 19:18:26 2011 NicoleSummarySUSFixed Reflective Photosensors; Recalibrated Photosensor 2

Thanks to Koji's help, the second photosensor, which was not working, has been fixed. I have re-calibrated the photosensor after fixing a problem with the circuit.  I have determined the new linear region to lie between 7.6 mm and 19.8mm. The slope defining the linear region is -0.26 V/mm (no longer the same as the first photosensor, which is -0.32 V/mm).

Here is the calibration plot.

5180   Wed Aug 10 22:47:22 2011 ranaSummaryVACVacuum Workstation (linux3) re-activated

For some reason the workstation at the vac rack was off and unplugged. Nicole and I plugged its power back in to the EX rack.

I turned it on and it booted up fine; its not dead. To get it on to the network I just made the conversion from 131.215 to 192.168 that Joe had done on all the other computers several months ago.

Now it is showing the Vacuum overview screen correctly again and so Steve no longer has to monopolize one of the Martian laptops over there.

5183   Thu Aug 11 06:45:14 2011 NicoleSummarySUSShaking Testing

Koji and I have finished shaking the table for the first round of measurements (horizontal shaking). We have cleaned up the lab space used.

The FFT Analyzer has been put back to its position at the back side of the rack (near the seismometers).

I will calibrate the photosensor for the suspension frame and piece together/analyze/produce graphs of the data today. If everything is fine (the measurements are fine) and if there is a chance, we hope to shake the TT suspension vertically.

5188   Thu Aug 11 12:31:39 2011 NicoleSummarySUSPhotosensor Head Calibration Curve for TT Frame

I have re-calibrated the photosensor I used to measure the displacements of the TT frame (what I call "Photosensor 2").

As before, the linear region is about 15.2mm to 25.4mm. It is characterized by the slope -0.0996 V/mm (-0.1 V/mm). Recall that photosensor 1 (used to measure mirror displacements) has a calibration slope of -3.2V/mm. The ratio of the two slopes (3.2/0.1 = 32). We should thus expect the DC coupling level to be 32? This is not what we have for the DC coupling levels in our data (2.5 for flexibly-supported, fully-assembled TT (with EDC, with bar), 4.2 for EDC without bar, 3.2 for rigid EDC without bar, 3.2 for no EDC, with bar, 3.2 for no EDC without bar) . I think I may need to do my calibration plot for the photosensor at the frame?

5191   Thu Aug 11 14:22:00 2011 NicoleSummarySUSPhotosensor Head Calibration Curve for TT Frame

 Quote: I have re-calibrated the photosensor I used to measure the displacements of the TT frame (what I call "Photosensor 2"). As before, the linear region is about 15.2mm to 25.4mm. It is characterized by the slope -0.0996 V/mm (-0.1 V/mm). Recall that photosensor 1 (used to measure mirror displacements) has a calibration slope of -3.2V/mm. The ratio of the two slopes (3.2/0.1 = 32). We should thus expect the DC coupling level to be 32? This is not what we have for the DC coupling levels in our data (2.5 for flexibly-supported, fully-assembled TT (with EDC, with bar), 4.2 for EDC without bar, 3.2 for rigid EDC without bar, 3.2 for no EDC, with bar, 3.2 for no EDC without bar) . I think I may need to do my calibration plot for the photosensor at the frame?

I have redone the voltage versus displacement measurements for calibrating "Photosensor 2" (the photosensor measuring the motions of the TT frame). This time, I calibrated the photosensor in the exact position it was in during the experimental excitation ( with respect to the frame ). I have determined the linear region to be 15.2mm to 22.9mm (in my earlier post today, when I calibrated the photosensor for another location on the frame, I determined the linear region to be 15.2mm to 25.4mm). This time, the slope was -0.92 V/mm (instead of -0.1 V/mm).

This means that the calibration ratio for photosensor 1 (measuring mirror displacements) and photoensor 2 (measuring frame displacements) is 34.86.

Since this "unity" value should be 34.86 for my transfer function magnitude plots (instead of the ~3 value I have), do I need to scale my data? It is strange that it differs by an order of magnitude...

5192   Thu Aug 11 14:32:12 2011 KojiSummarySUSPhotosensor Head Calibration Curve for TT Frame

The entry was quite confusing owing to many misleading wordings.

- The PS2 should be calibrated "as is". (i.e. should be calibrated with the frame)

- The previous calibrations with the highly reflective surface were 0.32V/mm and 0.26V/mm, respectively.
This time you have 0.10V/mm (with an undescribed surface). The ratio is not 32 but 3.2.

- The DC output of PS2 on the shaking setup was 2.5V. The DC output seen in the plot is 3.5V-ish.
This suggests the possibiliteies:
1) The surface has slightly higher reflectivity than the frame
2) The estimation of the distance between the frame and the PS2 during the TF measurement was not accurate.

- The word "DC coupling level" is misleading. I guess you mean the DC value of the vbration isolation transfer function
of the suspension.

 Quote: I have re-calibrated the photosensor I used to measure the displacements of the TT frame (what I call "Photosensor 2"). As before, the linear region is about 15.2mm to 25.4mm. It is characterized by the slope -0.0996 V/mm (-0.1 V/mm). Recall that photosensor 1 (used to measure mirror displacements) has a calibration slope of -3.2V/mm. The ratio of the two slopes (3.2/0.1 = 32). We should thus expect the DC coupling level to be 32? This is not what we have for the DC coupling levels in our data (2.5 for flexibly-supported, fully-assembled TT (with EDC, with bar), 4.2 for EDC without bar, 3.2 for rigid EDC without bar, 3.2 for no EDC, with bar, 3.2 for no EDC without bar) . I think I may need to do my calibration plot for the photosensor at the frame?

ELOG V3.1.3-