40m QIL Cryo_Lab CTN SUS_Lab TCS_Lab OMC_Lab CRIME_Lab FEA ENG_Labs OptContFac Mariner WBEEShop
 40m Log, Page 264 of 346 Not logged in
ID Date Author Type Category Subject
4802   Thu Jun 9 20:10:38 2011 kiwamuUpdateSUSETMY whitening filter : all off

I checked the state of the whitening filters for the ETMY shadow sensors.

Result : They've been OFF  (i.e. flat response).

(measurement and setup)

I measured the transfer functions of the whitening board (D000210) by looking at the signal before and after the whitening stage.

The whitening board handles five signals; UL, UR, LR, LL and SD, and there are five single-pin lemo outputs for each signal on the front panel.

A good thing on those lemo monitors is that their signals are monitored before the whitening stages.

Rana suggested me to use these signals for the denominator of the transfer functions and consider the sensor signals as excitation signals.

So I plugged those signals into extra ADC channels via an AA-board and measured the transfer functions.

In the measurement the coherence above 4 Hz was quite small while the suspension was freely swinging.

Therefore I had to excite the ETMY suspension by putting random noise in a frequency band from 5 Hz to 35 Hz to obtain better coherence.

(results)

The response is flat over frequency range from ~ 0.2 Hz to ~40 Hz, see the plot below.

According to the spectrum of each signal the measurements above 10 Hz are just disturbed by the ADC noise.

If the whitening filters are ON, a pole and zero are expected to appear at 30 Hz and 3 Hz respectively according to the schematic, but no such features.

4806   Fri Jun 10 18:49:40 2011 kiwamuUpdateIOOIntensity Noise after the MC

Last night the relative intensity noise (RIN) of the beam after MC was measured.

It looks like the RIN is dominated by the motion of the MC mirrors, possibly the angular motions because we don't have any angular stabilization servos.

Suresh will estimate the contribution from the MC mirrors' angular motion to the RIN in order to see if this plot makes sense.

(RIN)

The spectrum below 30 Hz seems to be dominated by the motion of the MC suspensions because it very resembles the spectra of those.

Above 30 Hz the spectrum becomes somehow flat, which I don't know why at the moment.

A rough estimation of the shot noise gave me a level of 10^{-9} RIN/sqrtHz, which is way below the measured spectrum.

(Setup)

All of the suspended mirrors were intentionally misaligned except for the MC mirrors and PRM to avoid interference from the other optics.

In this setup it allows us to measure the intensity noise of the laser which is transmitted from MC.

The beam transmitted from MC is reflected by PRM and finally enters into the REFL11 RFPD.

The DC signal from the RFPD was acquired at C1:LSC-REFL_DC_DQ as the laser intensity.

As well as the RIN measurement I took a spectrum when the beam is blocked by a mechanical shutter on the PSL table.

This data contains the dark noise from REFL11 and circuit noise from the whitening, AA board and ADC. It is drawn in black in the plot.

The cut off at 15 Hz is possibly due to the digital unwhitening (two poles at 15 Hz and two zeros at 150 Hz) filter to correct the analog whitening filter.

4824   Wed Jun 15 15:18:01 2011 kiwamuUpdateGeneralWednesday cleaning

[Jenne / Kiwamu]

We spent approximately an hour for the weekly Wednesday cleaning.

This time we moved onto an area where a desk and optics shelf reside along the Y arm.

We will continue cleaning up there in the next time too.

4832   Fri Jun 17 16:05:07 2011 kiwamuUpdateABSLLightWave out of MOPA box

[Suresh / Kiwamu]

We did the following things :

- Took the LightWave NPRO out from the MOPA box

- Temporarily took out the laser controller which has been connected to the Y end laser.

- Put the LightWave on AP table and plugged the laser controller and confirmed that it still emits a beam

[Things to be done]

- measure the beam profiles and power

- get a laser controller, which will be dedicated for this laser, from Peter King

[Background and Motivation]

The PRC and SRC length have to be precisely measured before the vent.

In order to measure those absolute length we are going to use the Stochino technique, which requires another laser to scan the cavity profiles.

The LightWave NPRO laser in the MOPA box was chosen for the Stochino laser because it has a large PZT range of 5 MHz/V and hence allows us to measure a wider frequency range.

The laser in the MOPA box had been connected to home-made circuits, which are not handy to play with. So we decided to use the laser with the usual laser controller.

Peter King said he has a LightWave laser controller and he can hand it to us.

Until we get the controller from him we do some preparations with temporary use of the Y end laser controller.

4835   Mon Jun 20 00:59:02 2011 kiwamuSummaryGeneralWeekly report
This is a summary for the week ending June 19th. Feel free to edit this entry.
(Number of elog entries = 27)

* Refinement of LSC screen
-> Kissel buttons and some indicators were newly installed
-> A script to autonatically generate kissel buttons was made

* New BIO installed on ETMY

* LightWave for ABSL
-> taken out from the MOPA box and put on the AP table with temporary use of the Y end laser controller

* Shipping 2 RFPDs to LLO

* LEDs on the BIO for the vertex suspensions were blown
-> fixed and re-installed. A test script will be prepared

* PEM AA board was fixed

* A plot of the MICH noise was produced for the first time

* Schnupp asymmetry measurement : Las = 3.64+/-0.32cm

* The photo diode on WFS2 has been replaced by YAG-444-4A

* SUS binary IO crates were taken out

* Fiber died
->C1LSC was unable to communicate to C1SUS. Installing a new copper Dolphine fixed the issue.

* SURF students came
4840   Mon Jun 20 11:38:49 2011 kiwamuUpdateABSLI-P curve of LightWave M126-1064-700

The I-P curve of the LightWave NPRO (M126-1064-700), which was taken out from the MOPA box, was measured. It looks healthy.

The output power can go up to about 1 W, but I guess we don't want it to run at a high power to avoid any further degradation since the laser is old.

X-axis is the current read from the display of the controller. Y-axis is the output power, directly measured by Coherent PM10.

The measurement was done by changing the current from the controller.

 Quote from #4832 [Things to be done]    - measure the beam profiles and power    - get a laser controller, which will be dedicated for this laser, from Peter King

4850   Tue Jun 21 20:35:50 2011 kiwamuUpdateLSCa script to measure sensing matrix

Last night I was making a script which will measure the sensing matrix using the realtime LOCKIN module.

The script is a kind of expansion of Jamie's one, which measure the asymmetry, to more generic purpose.

It will shake a suspended optic of interest and measure the response of each sensor by observing the demodulated I and Q signals from the LOCKIN module.

I will continue working on this.

(current status)

- made a function that drives the LOCKIN oscillator and get the data from the I and Q outputs.

- checked the function with the MICH configuration.

ITMX, ITMY and BS were shaken at 100 Hz and at different time.

Then the response of AS55_Q showed agreement with what I got before for the actuator calibration (see this entry).

It means the function is working fine.

4851   Tue Jun 21 23:29:41 2011 kiwamuUpdateLSCsensing matrix measurement

I am now measuring the sensing matrix in the DRMI configuration.

A goal of tonight is to measure the sensing matrix as a test of the script.

The result will be updated later.

4855   Wed Jun 22 15:24:10 2011 kiwamuUpdateABSLgot a laser controller for LightWave

Peter King came over to the 40m with a laser controller and gave it to us.

We will test it out with the LightWave NPRO, which was used for MOPA.

4857   Wed Jun 22 17:42:03 2011 kiwamuUpdateLSCsensing matrix measurement

The sensing matrix was measured in the DRMI configuration for the first time.

The measurement was done by an automatic script and the realtime LOCKIN module built in the c1lsc model.

The resultant matrix is still too primitive, so I will do some further analysis.

(Measurement of sensing matrix)

The quantities we want to measure are the transfer functions (TFs) from displacement (or change in optical phase) of each DOF to sensors in unit of [counts/m].

So essentially the measurement I did is the same as the usual TF measurement. The difference is that this measurement only takes TFs at a certain frequency, in this case 283 Hz.

The measurement goes in the following order :

(1) Lock DRMI

(2) Shake an optic of interest longitudinally with an amplitude of 1000 counts at 283.103 Hz, where no prominent noise structures are present in any spectra of the sensor signals.

(3) Put a notch filter at the same frequency of 283.103 Hz in each DOF (MICH, PRC and SRC) to avoid unwanted suppression due to the control loops.

(This technique is essentially the same as this one, but this time the control loops are shut off only at a specific frequency )

The notch filter I put has a depth of 60 dB and Q of 20. The filter eats the phase of ~10 deg at 200 Hz, which still allow servos to run with a high UGF up to 200Hz.

(4) Take the output signal from a signal port of interest (i.e. REFL11_I, etc.,) and then put it into the realtime LOCKIN module.

(5) Measure the resultant I and Q signals coming out from the LOCKIN module.

(6) Repeat the procedure from (2) through (5) for each optic and sensor.

(Results)

Again, the resultant sensing matrix is still primitive, for example the optic-basis should be converted into the DOF basis.

The values listed in the matrix below is the absolute values obtained by operation of sqrt( I^2 + Q^2) plus the polarity according to the output from I and Q of LOCKIN.

Therefore they still contain the actuator response, which is not desired. i will calibrate them into [counts/m] later by using the calibration factor of the actuator responses.

All the raw data showed the relative phase between I and Q either ~ 127 deg or ~ -53 deg.

In my definition, the one has 127 deg is plus polarity and the one has -53 deg is minus polarity.

Technically speaking the polarity depends on the polarity of the actuator and also the direction of the actuator against the DOFs.

Without any excitation the absolute values fluctuated at about 10-4 - 10-5, so the excitation amplitude was big enough to observe the sensing matrix.

Though, I still need to estimate the statistical errors to make sure the SNR is reasonably big.

Fig.1 Measured sensing matrix from optic to sensors.

(Things to be done)

- convert the optic-basis (i.e. BS, ITMs, PRM and SRM) to the DOF-basis (i.e. MICH, PRC and SRC) so that the matrix is understandable from point of view of the interferometer control.

- estimate the optimum demodulation phase for each DOF at each sensor port.

- add some statistical flavors (e.g. error estimations and so on.)

- edit the script such that it will keep watching the ADC overflows and the coherence to make sure the measurement goes well.

- add some more signal ports (e.g. REFL55, POY55 and etc.)

- compare with an Optickle model

 Quote from #4851 The result will be updated later.

4863   Thu Jun 23 05:22:51 2011 kiwamuUpdateLSCPRMI locking : not stable enough

I was trying to measure the sensing matrix in the PRMI configuration, but basically gave up.

It is mainly because the lock of PRMI wasn't so stable and it didn't stay locked for more than a minute.

It looked like an angular motion fluctuated a lot around 1- 3 Hz. The beam spot on the AS camera moved a lot during the lock.

I have to figure out who is the bad suspension and why.

4867   Thu Jun 23 21:34:21 2011 kiwamuUpdateCDSno foton on the CentOS machines

For some reasons foton's deafault sample rate is NOT correct when it runs on the CentOS machines.

It tries to setup the sample rate to be 2048 Hz instead of 16384 Hz until you specify the frequency.

To avoid an accidental change of the sample rate,

running foton on CentOS is forbidden until any further notifications.

Run foton only on Pianosa.

Additionally I added an alias sentence in cshrc.40m such that people can not run foron on CentOS (csh and tcsh, technically speaking).

Below is an example of raw output when I typed foron on a CentOs machine.

    rossa:caltech>foton     DO NOT use foton on CentOS 

4871   Thu Jun 23 22:53:02 2011 kiwamuUpdateCDSran activateDQ.py

I found some DQ channels (e.g. SENSOE_UL and etc.) for C1SUS haven't been activated, so I ran activateDQ.py.

Then I restarted daqd on fb as usual. So far the DQ channels look working fine.

4872   Thu Jun 23 22:59:45 2011 kiwamuUpdateABSLI-P curve of LWE

The I-P curve was measured again, but this time in a lower current range of 1.0-1.9 [A].

The plot below is the latest I-P curve.

(Decision)

Based on the measurement and some thoughts, I decided to run this laser at about 1.8 [A] which gives us a middle power of ~ 360 [mW].

In the 40m history, the laser had been driven at 2.4 [A] in years of approximately 2006-2009, so it's possible to run it at such a high power,

but on the other hand Steve suggested to run it with a smaller power such that the laser power doesn't degrade so fast.

(notes)

The laser controller handed from PK (#4855) was used in this measurement.

The nominal current was tuned to be 1.8 [A] by tuning a potentiometer on the laser head (see page.18 on the manual of LWE).

There was a huge bump around 1.4 [A] and sudden power drop at 1.48 [A] although I don't know the reason.

 Quote from #4842 The old days the NPRO ( inside the MOPA ) was running ~1.7A  500 mW

4874   Fri Jun 24 00:13:24 2011 kiwamuUpdateABSLbeam profile measurement of LWE

The beam profile of the LWE (LightWave Electronics) NPRO was measured.

Mode matching telescopes will be designed and setup soon based on the result of the measurements.

Here is a plot of the measured beam profile.

(some notes)

The measurement was done by using Kevin's power attenuation technique (#3030).

An window was put just after the NPRO and the reflected beam was sampled for the measurement to avoid the beam scan saturated.

4884   Sat Jun 25 06:09:38 2011 kiwamuUpdateLSCFriday locking

I was able to measure the sensing matrix in the PRMI configuration.

The results will be posted later.

4885   Sun Jun 26 16:02:12 2011 kiwamuUpdateIOOFriday MC activity

[Rana / Kiwamu]

Last Friday we did several things for MC :

- aligned the incident beam to MC

- increased the locking gain by 6 dB and modified the auto-locker script accordingly

- improved the alignment of the beam on the MC_REFLPD photo diode

(Motivation)

In the beginning of the work, we wanted to know what RF frequency components are prominent in the reflection from MC.

Since the WFS circuits are capable for two RF notches, we wanted to determine which frequencies are appropriate for those notches.

So for the purpose we tried searching for unwanted RF components in the reflection.

However during the work, we found several things that needed to be fixed, so we spent most of the time for improving the MC locking.

(Some notes)

- Alignments of the incident beam

At the beginning, the reflection from MC was about 2.2 in C1:IOO-REFLDC and the lock of MC had been frequently unlocked.

This situation of high reflection seemed to be related to a work done by Suresh (#4880).

Rana went to the PSL table and tweaked two input steering mirrors in the zig-zag path, and finally the reflection went down to ~ 0.8 in C1:IOO-REFLDC.

This work made the lock more robust.

- Change of the locking gain

After the alignment of the incident beam, we started looking at the time series of the MC_REFLPD signal with an oscilloscope as a start point.

What we found was a significant amount of 30 kHz components. This 30 kHz oscillation was thought be a loop oscillation, and indeed it was so.

We increased the loop gain by 6 dB and then the 30 kHz components disappeared successfully.

So the nominal locking gain of MC is now 11 dB in C1:IOO-MC_REFL_GAIN. The auto locker script was also modified accordingly.

- RF components in the MCREFL signal

After those improvements mentioned above, we started looking at the spectrum of the MCREFL PD using the spectrum analyzer HP8590.

The 29.5 MHz component was the biggest components in the spectrum. Ideally this 29.5 MHz signal should be zero when MC is locked.

One possible reason for this big 29.5 MHz signal was because the lock point was off from the resonant point.

We tweaked the offset in the MC lock path using a digital offset, C1:IOO-MC-REFL_OFFSET.

We found an offset point where the 29.5MHz signal went to the minimum, but didn't go to zero.

(works to be done)

So it needs some more works to investigate the cause of nonzero 29.5 MHz signal as well as investigation of what RF components should be notched out.

A good start point would be writing a GPIB interface script such that we can get the spectra from HP8590 without any pains.

4890   Mon Jun 27 10:04:29 2011 kiwamuSummaryGeneralWeekly report

Summary for the week ending June 26th.  (Number of elog entries = 53)

- SUS
A BIO installed on 1X2.
A peak finding script was prepared for diagonalization of the OSEM input matrices
The suspension readout coefficients were changed to have unit of [um] and [urad] in each signal.

- ABSL
LWE NPRO controller was brought by Peter King.
The I-P cuvre and beam profile was measured. Nominal current was chosen to 1.8 [A].
The access tube between PSL and AS table was back in place.

-RFPD
The REFL55 characterization was analyzed (impedance gain = 615 Ohm, shot noise intercept current = 1.59 mA )

- MC
WFS1 check, the 29MHz resonance need to be adjusted.
The MC locking gain was increased by 6 dB to avoid an oscillation at 30 kHz.

- LSC
The sensing matrices were measured in DRMI configuration and PRMI configuration

- Fiber experiment
QPDY_PD was repositioned to accommodate the fiber stuff on the ETMY table.
Succeeded in introducing the IR beam into the fiber coupler.

- TT characterization
Th optic bench next to MC2 was cleaned up and leveled

- Vent list wiki page
A wiki page was made for the vent detailed plan.

- CDS
A foton's malfunction was found. It can run correctly only on Pianosa.
Some Dell machines were gone to Rod Luna

- 40m specfic safety training for the SURFs
4898   Tue Jun 28 14:21:41 2011 kiwamuUpdateIOOsomething wrong ? : Power incident on REFL11 and REFL55

The measured change in the REFL DC power with and without PRM aligned seems unacceptably small.  Something wrong ?

The difference in the power with and without PRM aligned should be more than a factor of 300.

[difference in power] = [single bounce from PRM] / [two times of transmission through PRM ]

= (1-T) / T^2 ~ 310,

where T is the transmissivity of PRM and T = 5.5% is assumed in the calculation.

Also the reflectivity of MICH is assumed to be 1 for simplicity.

 Quote from #4894 We now have (with the PRM misaligned): REFL11:  Power incident = 7.60 mW ;  DC out = 0.330 V  => efficiency = 0.87 A/W REFL55:  Power incident = 23 mW ;  DC out = 0.850 V  => efficiency = 0.74 A/W and with the PRM aligned:: REFL11:  DC out = 0.35 V  => 8 mW is incident REFL55: DC out = 0.975 V  => 26 mW is incident

4899   Tue Jun 28 15:20:08 2011 kiwamuUpdateLSCsensing matrix measurement in PRMI configuration

Here is the result of the measurement of the sensing matrix in the PRMI configuration.

If we believe the resultant matrix, it is somewhat different from what we expected from a finesse simulation (summary of simulated sensing matrix).

(Motivation)

As a part of the DRMI test plan, we wanted to check the sensing matrices and consequently diagonalize the LSC input matrix.

The matrix of the DRMI configuration has been measured (#4857), but it was a bit too complicated as a start point.

So first in order to make sure we are doing a right measurement, we moved onto a simpler configuration, that is PRMI.

(measurement)

The technique I used was the same as before (#4857) except for the fact that SRM wasn't included this time.

- PRC was locked to the carrier resonant point. The UGF of MICH and PRC were ~ 110 Hz and 200 Hz respectively.

- Longitudinally shook BS, ITMs and PRM at 283.103 Hz with an amplitude of 1000 counts using the LOCKIN oscillator in C1LSC.

- Took the I and Q phase signals from the LOCKIN outputs.

The table below is the raw data obtained from this measurement :

(Conversion of matrix)

With the matrix shown above, we should be able to obtain the sensing matrix which gives the relation between displacements in each DOF to each signal port.

The measured matrix connects two vectors, that is,

 (signal port vector) = [Measured raw matrix] (SUS actuation vector),   -- eq.(1)

where

(signal port vector) = (AS55_I, AS55_Q, REFL11_I, REFL11_Q)T   in unit of [counts],

    (SUS actuation vector) = (BS, ITMX, ITMY, PRM)T   in units of [counts].

Now we break the SUS actuation vector into two components,

  (SUS actuation vector [counts])  = (actuator response matrix [m/counts])-1 * (MICH, PRM [m] )^T   -- eq.(2)

where

(actuator response matrix) =  2.05x10-13 * ( [1   ,  0.217, -0.216,   0  ],

                                                 [ 0.5,  0.109 -0.108, 0.862]  )  in unit of [m/counts]

These values are coming from the actuator calibration measurement.

In the bracket all the values are normalized such that BS has a response of 1 for MICH actuation.

Combining eq.(1) and (2) gives,

    (signal port vector) = (measured raw matrix) * (actuator response matrix)-1 * (MICH, PRM)T

And now we define the sensing matrix by

(sensing matrix) = (measured raw matrix) * (actuator response matrix)-1

The sensing matrix must be 4x2 matrix.

For convenience I then converted the I and Q signals of each port into the absolute value and phase.

       ABS = sqrt((AAA_I)2 +(AAA_Q)2 ),

       PHASE = atan (AAA_Q / AAA_I),

where AAA is either AS55 or REFL11.

(Resultant matrix)

The table below is the resultant sensing matrix.

ABS represents the strength of the signals in unit of [cnts/m], and PHASE represents the demodulation phases in [deg].

There are several things which I noticed :

- The demodulation phase of MICH=>AS55 and PRC=>REFL11 are close to 0 or 180 deg as we expected.

This is a good sign that the measurement is not something crazy.

- AS55 contains a big contribution from PRC with a separation angle of 152 deg in the demodulation phase.

In AS55 the signal levels of MICH and PRC were the same order of magnitude but PRC is bigger by a factor of ~4.

However the finesse simulation (see wiki page) shows a different separation angle of 57 deg and MICH is bigger by factor of ~6.

- REFL11 is dominated by PRC. The PRC signal is bigger than MICH by a factor of ~100, which agrees with the finesse simulation.

However the separation angle between PRC and MICH are different. The measurement said only 19 deg, but the simulation said ~ 90 deg.

- Woops, I forgot to calibrate the outputs from the LOCKIN module.

The whole values must be off by a certain factor due to the lack of the calibration , but fortunately it doesn't change the demodulation phases.

 Quote from #4884 I was able to measure the sensing matrix in the PRMI configuration. The results will be posted later.

4910   Wed Jun 29 12:20:53 2011 kiwamuUpdateLSCsensing matrix measurement in PRMI configuration

Of course I made a mistake in my calculation of the sensing matrix. I will figure out which point I mistook.

The MICH signal must have the demodulation phase of around 90 deg in AS55

because we had adjusted the demodulation phase such that the MICH signal mostly appears on AS55_Q.

 Quote: Here is the result of the measurement of the sensing matrix in the PRMI configuration.

4911   Wed Jun 29 13:56:42 2011 kiwamuUpdateGeneralminutes of 40m meeting
4917   Thu Jun 30 03:26:40 2011 kiwamuUpdateABSLstatus update

Status update of the absolute length (ABSL) measurement:

- To accommodate the ABSL stuff, the AS path was relocated on the AP table.

(In this evening Jenne was able to lock MICH with AS55, so it's working fine.)

- On the AP table all of the necessary items, including the NPRO, a Faraday, some mirrors and etc., were in place

- The mode matching was coarsely done. The Rayleigh range looked reasonably long.

- Fine alignments will be done tomorrow

- Also a picture of the setup will be uploaded in the morning.

4923   Thu Jun 30 14:11:55 2011 kiwamuUpdateABSLa photo of ABSL setup on the AP table

Here is a picture of the latest ABSL setup at the east part of the AP table.

(Some notes )

- The ABSL laser is injected from the AP port.

- A 90 % reflection BS was installed just after the NPRO, this is for sampling a 10% of the laser to the PSL table.

However, I've just realized that this is not a nice way because the 10 % beam doesn't  go through the Faraday. Whoops.

- A polarzser cell at the input side of the Faraday doesn't let any beam go through it for some reasons (broken ?).

Therefore instead of having such a bad cell, a cube PBS was installed.

-  A room was left on the table for the AS165 RFPD (green-dashed rectangular in the picture).

 Quote from #4917 - Also a picture of the setup will be uploaded in the morning.

4925   Thu Jun 30 21:00:20 2011 kiwamuUpdateABSLfine alignment done

(Just a quick report)

The fine alignment of the ABSL laser injection was successfully done.

I was able to see the DRMI fringings at the AS camera. The ABSL beam is injected from the AS port, therefore what I saw on the camera was the reflection back from the interferometer.

(Things to be done)

-  A beat-note setup on the PSL table.

- Refinement of the mode matching. The beam spot on the AS camera is a bit bigger, so I should more tightly focus the injected beam.

 Quote from #4917 - Fine alignments will be done tomorrow

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

4939   Tue Jul 5 16:09:54 2011 kiwamuUpdateABSLsome photos for ABSL setup

Here I show two photos of the latest ABSL (ABSolute Length measurement) setup.

Figure.1 : A picture of the ABSL setup on the AP table.

The setup has been a little bit modified from the before (#4923).

As I said on the entry #4923, the way of sampling the ABSL laser wasn't so good because the beam, which didn't go through the faraday, was sampled.

In this latest configuration the laser is sampled after the faraday with a 90% beam splitter.

The transmitted light from the 90% BS (written in pink) is sent to the PSL table through the access tube which connects the AP and PSL table .

FIgure.2: A picture of the ABSL setup on the PSL table.

The 10% sampled beam ( pink beam in the picture) eventually comes to the PSL table via the access tube (the hole on the left hand side of the picture).

Then the ABSL beam goes through a mode matching telescope, which consists of a combination of a concave and a convex lens.

The PSL laser (red line in the picture) is sampled from a point after the doubling crystal.

The beam is combined at a 50 % BS, which has been setup for several purposes( see for example #3759 and #4339 ) .

A fast response PD (~1 GHz) is used for the beat-note detection.

4940   Tue Jul 5 17:38:46 2011 kiwamuUpdateABSLABSL laser frequency-locked

In this past weekend the ABSL laser was successfully frequency-locked to the PSL laser with a frequency offset of about 100 MHz.

In the current setup a mixer-based frequency discriminator is used for detection of the beat-note frequency.

Setup for frequency locking

The diagram below shows the setup for the frequency locking.

(UGF)
According to a brief check of the loop oscillation it implies that the UGF is around 40 kHz.
Of course I will measure the open-loop over a wide frequency range at some point.
The lock was quite robust and it was able to stay locked for more than an hour as far as I observed.

(Beat-note detection and its amplification)
The fast RFPD, which is standing on the PSL table to detect the beat-note (see the picture on #4939), showed the signal level of -16 dBm.
Then the signal goes through the RF amplifier stage to have an appropriate power level at the mixer in the frequency detection stage.
Before the signal goes into the amp. stage I put a power splitter so that I can see a signal on a spectrum analyzer.

(Frequency detection)
In the mixer-based frequency discriminator, the length difference between two coax. cable was chosen to be 1 m.
This length difference gives us a zero cross point (operation point) of ~100 MHz and linear range of ~ +/-100MHz, which can sufficiently cover the FSR of PRC: 22MHz.

(Control filter)
After the signal goes through the freq. discriminator, a low noise amplifier, ITHACO 1201 was installed as a control filter.
The reason I chose ITHACO 1201 was that it has a larger output range than that of SR560.
ITHACO 1201 can go to +/- 15V, which means the ABSL laser should be able to track the frequency by about +/- 65 MHz without a thermal actuation.
Right now a single pole was put at 1 Hz for an easy lock.
The output from 1201 goes directly to the laser PZT, whose input is on the front panel of the laser controller.

Temperature setpoints

During the work I found three temperature points, where we can observe the beat-note signal within a bandwidth of 1 GHz.
Here is a summary of the temperature set points :
PSL temperature = 31.71 deg
ABSL temperature = 44.19 deg (not good),
47.25 deg (chosen to be nominal set point),
50. 23 deg
The first one (44.19 deg) wasn't good because changing the temperature of the ABSL laser also changes the amplitude of the beat-note significantly.
In a worst case the signal completely disappeared when the ABSL laser was at a certain temperature close to 44.19 deg.
The other two temperature points seemed good. I eventually chose the second one (47.25 deg) for the nominal set point.
Note that the current readout has been 1.81 A on the laser controller.
4943   Wed Jul 6 02:12:36 2011 kiwamuUpdateSUSRe : More normalization of all sus controllers

[Jenne / Rana/ Kiwamu]

We found the 30 Hz high pass filters had lower gain than what they used to be at low frequcnies.

So we increased the gain of the high pass filters called '30:0.0'  by a factor of 10 to have the same gain as before.

Now all the suspension shows some kind of damping. Needs more optimizations, for example Q-adjustments for all the suspensions...

 Quote from #4942 This is getting closer, but with the whitening left OFF and the cts2um filter also OFF, none of the suspensions are working correctly.

4948   Wed Jul 6 18:15:26 2011 kiwamuUpdateSUSRe: BS oplev spectra

[Steve / Kiwamu]

Motivation:

Since the oplevs were the ones we haven't carefully tested, so the oplevs need to be checked.

This checking is also a part of the suspension optimizations (see the minutes of the last 40m meeting).

In this work Steve will check two things for all the oplevs :

1. Noise level including the dark noise, electrical noise and ADC noise to just make sure that the noise are blow the signal levels below ~ 30Hz.

2. The spectra of the signals to make sure there are no funny oscillations and unexpected structures

Measurement :

To check the things listed above, we take two kinds of oplves' spectra :

1. "dark noise" when the He-Ne beam is blocked.

2. "signals" when the optics are damped by only OSEMs

We did these checks on the BS oplev today (see the last entry).

All of them are fine, for example the dark noise (including electrical noise and ADC noise) are below the signal levels.

And no oscillation peak was found. Steve will go through all of the oplevs in this way.

 Quote from #4947 Healthy BS oplev

4949   Wed Jul 6 23:03:57 2011 kiwamuUpdateLSCmodified locking scripts

[Jenne / Kiwamu]

Last night we modified the locking scripts, that were called from C1IFO_CONFIGURE.adl, to adapt them to the new "PRCL" and "SRCL" convention.

So far they work fine and quitted dumping some error messages about inexistence of these channel names.

P.S. The locking scripts have been summarized on the 40m wiki

 Quote from #4912 - Now the power and signal recycling cavity lengths are named "PRCL" and "SRCL" in stead of three letter names without "L". We should change the locking script to accomodate these changes.

4950   Wed Jul 6 23:53:38 2011 kiwamuSummaryGeneralminutes of 40m meeting
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.

5030   Mon Jul 25 13:01:24 2011 kiwamuUpdateCDSc1ioo Make problem

[Suresh / Kiwamu]

# HELP US Jamieeeeeeee !! We are unable to compile c1ioo.

It looks like something wrong with Makefile.

We ran make c1ioo -- this was successful every time. However make install-c1ioo doesn't run.

The below is the error messages we got.

make install-target-c1ioo
make[1]: Entering directory `/opt/rtcds/caltech/c1/core/branches/branch-2.1'

Then we looked at Makefile and tried to find what was wrong. Then found the sentence (in 36th line from the top) saying

if test $(site)no = no; then echo Please make$\$system first; exit 1; fi;\

We thought the lack of the site-name specification caused the error.

So then we tried the compile it again with the site name specified by typing

export site=c1

in the terminal window.

It went ahead a little bit further, but it still doesn't run all through the Make commands.

5040   Wed Jul 27 01:58:23 2011 kiwamuUpdateLSClocking status

Through some locking exercise I found that several things are degrading.

Remember the interferometer is like a cat, so we have to feed and take care of her everyday. (Otherwise the cat will be dead !)

Beam axis:

I guess that the beam axis has changed a lot to the horizontal direction.
The beam spots on the REFL and AS camera looked off-centered by a size of the spot.
The beam axis has to be well-aligned before the vent.

Locking of the Arms :

didn't lock at all. It could be a problem of the demodulation phase on AS55.
Also the TRY camera looked pretty much off-centered. The spot is already getting out from the field of view.
We have to fix this issue, otherwise we cannot align the beam axis.

Locking of PRM :

Sort of okay, I was able to lock both MICH and PRCL although I had to flip the sign of the MICH control gain due to the demod-phase change.
The suspensions don't look healthy. The beam spots on the REFL and AS camera move a lot even without any length feedback.
It means some of the suspensions are shaky.
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)

5053   Thu Jul 28 16:00:28 2011 kiwamuUpdateComputer Scripts / Programsanother offset script : offset2

A new offset-zeroing script has been developed and it is ready to run.

The motivation is to replace the old zeroing script called offset by a better one because this old script somehow failed to revert the gain settings on a given filter bank.

The new script, named offset2, does the same job, but uses tdsavg instead of using ezcaservo. So it doesn't screw up the gain settings.

Additionally the structure of the script is much simpler than the old offset script, and fewer ezca-functions.

I will modify some scripts which use the old offset script so that all the offset-zeroing is done by offset2.

P.S.

Useful scripts are listed on the 40m wiki

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

5054   Thu Jul 28 16:10:34 2011 kiwamuUpdateLSCBoth arm locked

[Nicole / Jamie / Rana / Kiwamu]

The X arm and Y arm have been locked.

The settings for the locking were stored on the usual IFO_CONFIGURE scripts, so anybody can lock the arms.

In addition to that Nicole, Jamie and Rana re-centered the beam spot on the ETMY_TRANS camera and the TRY PD.

The next step is to activate the C1ASS servo and align the both arms and beam axis.

Xarm locking notes:

* Changed TRX gain from -1 to -0.02. Without this 50x reduction the arm power was not normalized.

* Had to fix trigger matrix to use TRX for XARM and TRY for YARM. Before it was crazy and senseless.

* Lots of PZT alignment. It was off by lots.

* Yarm trans beam was clipping on the steering mirrors. Re-aligned. Needs to be iterated again. Be careful when bumping around the ETMY table.

* YARM gain was set to -2 instead of -0.2. Because the gain was too high the alignment didn't work right.

ALWAYS HAVE an OPEN DATAVIEWER with the standard ARM channels going when doing ANY INTERFEROMETER WORK.

THIS IS THE LAW.

5062   Fri Jul 29 16:25:06 2011 kiwamuUpdateASCbeam axis and Y arm aligned

Last night I aligned the incident beam axis and the Yarm by touching the PZT mirrors and the suspensions.

I didn't estimate how good they were aligned, but I guess the Y arm is now ready for the Y green light.

Next : Y green alignment and the MC spots measurement / alignment.

++ Motivation ++

Prior to the coming vent we want to have the Y arm, incident beam axis and Y green light aligned so that we can align some necessary optics in the chamber.

Also alignment of the incident beam will allow us to re-position the incident beam alignment monitor (i.e. IPPOS and IPANG).

Our plan was to first align the Y arm using the ASS system and then align the Y green light to the Y arm.

++ what I failed ++

First I was trying to measure the spot positions on the MC mirrors to make me sure the beam axis has/hasn't changed.

Also I was going to align the MC suspensions to have nice spot position on each suspension using the MCASS system

because this will help us checking the beam clearance in the Faraday and perhaps re-positioning of the Faraday during the coming vent.

But essentially I failed and eventually gave up because MCASS didn't work. It seems that MCASS needs some modifications in the scripts.

Then, to make me feel better I moved on to the Y arm and beam axis alignment.

++ what I did ++

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

However the drive signals from ASS and its demodulated signals looked fine. Only the feedback did not work correctly.

Every time I enabled the feedback paths, the arm just lost the lock. Something is wrong in the feedback paths.

Then I started to align the cavity by my hands while looking at the demodulated signal from each LOCKIN module.

I aligned the things until each demodulated signal fluctuates around zero.

At the end the beam spots on the ETMY and ITMY camera looked well-aligned and the transmitted light became larger by a factor of 2ish.

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.

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.

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.

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.

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

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.

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.

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 !

ELOG V3.1.3-