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ID Date Authorup Type Category Subject
  10986   Sat Feb 7 13:34:11 2015 KojiSummaryPSLISS AOM driver check

I wanted to check the status of the ISS. The AOM driver response was measured on Friday night.
The beam path has not been disturbed yet.

- I found the AOM crystal was removed from the beam path. It was left so.

- The AOM crystal has +24V power supply in stead of specified +28V.
  I wanted to check the functionality of the AOM driver.

- I've inserted a 20dB directional coupler between the driver and the crystal.
  To do so, I first turned off the power supply by removing the corresponding fuse block at the side panel of the 1X1 Rack.
  Then ZFDC-20-5-S+ was inserted, the coupled output was connected to a 100MHz oscilloscope with 50Ohm termination.
  Then plugged in the fuse block again to energize the driver box.

  Note that the oscilloscope bandwidth caused reduction the amplitude by a factor of 0.78. In the result, this has already been compensated.

- First, I checked the applied offset from a signal generator (SG) and the actual voltage at the AOM input. The SG OUT
  and the AOM control input are supposed to have an impedance of 50Ohm. However, apparently the voltage seen at the
  AOM in was low. It behaved as if the input impedance of the AOM driver is 25Ohm.
  In any case, we want to use low output impedance source to drive the AOM driver, but we should keep this in mind.

- The first attachment shows the output RF amplitude as a function of the DC offset. The horizontal axis is the DC voltage AT THE AOM INPUT (not at the SG out).
  Above 0.5V offset some non linearity is seen. I wasn't sure if this is related to the lower supply voltage or not. I'd use the nominal DC of 0.5V@AOM.

  The output with the input of 1V does not reach the specified output of 2W (33dBm). I didn't touch the RF output adjustment yet. And again the suppy is not +28V but +24V.

- I decided to measure the frequency response at the offset of 0.53V@AOM, this corresponds to the DC offset of 0.8V. 0.3Vpp oscillation was given.
  i.e. The SG out seen by a high-Z scope is V_SG(t) = 1.59 + 0.3 Sin(2 pi f t) [V]. The AOM drive voltage V_AOM(t) = 0.53 + 0.099 Sin(2 pi f t).
  From the max and min amplitudes observed in the osciiloscope, the response was checked. (Attachment 2)
  The plot shows how much is the modulation depth (0~1) when the amplitude of 1Vpk is applied at the AOM input.
  The value is ~2 [1/V] at DC. This makes sense as the control amplitude is 0.5, the applied voltage swings from 0V-1V and yields 100% modulation.

  At 10MHz the first sign of reduction is seen, then the response starts dropping above 10MHz. The specification says the rise time of the driver is 12nsec.
  If the system has a single pole, there is a relationship between the rise time (t_rise) and the cut-off freq (fc) as fc*t_rise = 0.35 (cf Wikipedia "Rise Time").
  If we beieve this, the specification of fc is 30MHz. That sounds too high compared to the measurement (fc ~15MHz).
  In any case the response is pretty flat up to 3MHz.

  11000   Wed Feb 11 03:41:12 2015 KojiUpdateLSCPRC error signal RF spectra

As the measurements have been done under feedback control, the lower RF peak height does not necessary mean
the lower optical gain although it may be the case this time.

These non-33MHz signals are embarassingly high!
We also need to check how these non-primary RF signals may cause spourious contributions in the error signals,
including the other PDs.

  11005   Wed Feb 11 18:11:46 2015 KojiSummaryLSC3f modulation cancellation

33MHz sidebands can be elliminated by careful choice of the modulation depths and the relative phase between the modulation signals.
If this condition is realized, the REFL33 signals will have even more immunity to the arm cavity signals because the carrier signal will lose
its counterpart to produce the signal at 33MHz.

Formulation of double phase modulation

m1: modulation depth of the f1 modulation
m2: modulation depth of the f2 (=5xf1) modulation

The electric field of the beam after the EOM

E=E_0 \exp \left[ {\rm i} \Omega t + m_1 \cos \omega t +m_2 \cos 5 \omega t \right ]
\flushleft = {\it E}_0 e^{{\rm i} \Omega t} \\ \times \left[ J_0(m_1) + J_1(m_1) e^{{\rm i} \omega t}- J_1(m_1) e^{-{\rm i} \omega t} + J_2(m_1) e^{{\rm i} 2\omega t}+ J_2(m_1) e^{-{\rm i} 2\omega t} + J_3(m_1) e^{{\rm i} 3\omega t}- J_3(m_1) e^{-{\rm i} 3\omega t} + \cdots \right] \\ \times \left[ J_0(m_2) + J_1(m_2) e^{{\rm i} 5 \omega t}- J_1(m_2) e^{-{\rm i} 5 \omega t} + \cdots \right]
\flushleft = {\it E}_0 e^{{\rm i} \Omega t} \\ \times \left\{ \cdots + \left[ J_3(m_1) J_0(m_2) + J_2(m_1) J_1(m_2) \right] e^{{\rm i} 3 \omega t} - \left[ J_3(m_1) J_0(m_2) + J_2 (m_1) J_1(m_2) \right] e^{-{\rm i} 3 \omega t} + \cdots \right\}

Therefore what we want to realize is the following "extinction" condition
J_3(m_1) J_0(m_2) + J_2(m_1) J_1(m_2) = 0

We are in the small modulation regime. i.e. J0(m) = 1, J1(m) = m/2, J2(m) = m2/8, J3(m) = m3/48
Therefore we can simplify the above exitinction condition as

m_1 + 3 m_2 = 0

m2 < 0 means the start phase of the m2 modulation needs to be 180deg off from the phase of the m1 modulation.

E = E_0 \exp\left\{ {\rm i} [\Omega t + m_1 \cos \omega t + \frac{m_1}{3} \cos (5 \omega t + \pi)] \right \}

Field amplitude m1=0.3, m2=-0.1 m1=0.2, m2=0.2
Carrier 0.975 0.980
1st order sidebands 0.148 9.9e-2
2nd 1.1e-3 4.9e-3
3rd 3.5e-7 6.6e-4
4th 7.4e-3 9.9e-3
5th 4.9e-2 9.9e-2
6th 7.4e-3 9.9e-3
7th 5.6e-4 4.9e-4
8th 1.4e-5 4.1e-5
9th 1.9e-4 5.0e-4
10th 1.2e-3 4.9e-3
11th 1.9e-4 5.0e-4
12th 1.4e-5 2.5e-5
13th 4.7e-7 1.7e-6
14th 3.1e-6 1.7e-5
15th 2.0e-5 1.6e-4


  11012   Thu Feb 12 11:59:58 2015 KojiUpdateLSCNew Locking Paradigm - Loop-gebra

The goals are:

- When the REFL path is dead (e.g. S_REFL = 0), the system goes back to the ordinary ALS loop. => True (Good)

- When the REFL path is working, the system becomes insensityve to the ALS loop
(i.e. The ALS loop is inactivated without turning off the loop.) => True when (...) = 0

Are they correct?


Then I just repeat the same question as yesterday:

S is a constant, and Ps are cavity poles. So,  approximately to say, (...) = 0 is realized by making D = 1/G_REFL.
In fact, if we tap the D-path before the G_REFL, we remove this G_REFL from (...). (=simpler)
But then, this means that the method is rather cancellation between the error signals than
cancellation between the actuation. Is this intuitively reasonable? Or my goal above is wrong?

  11019   Thu Feb 12 23:47:45 2015 KojiUpdateLSC3f modulation cancellation

- I built another beat setup on the PSL table at the South East side of the table.
- The main beam is not touched, no RF signal is touched, but recognize that I was present at the PSL table.
- The beat note is found. The 3rd order sideband was not seen so far.
- A PLL will be built tomorrow. The amplifier box Manasa made will be inspected tomorrow.

- One of the two beams from the picked-off beam from the main beam line was introduced to the beat setup.
(The other beam is used of for the beam pointing monitors)
There is another laser at that corner and the output from this beam is introduced into the beat setup.
The combined beam is introduced to PDA10CF (~150MHz BW).

- The matching of the beam there is poor. But without much effort I found the beat note.
  The PSL laser had 31.33 deg Xtal temp. When the beat was found, the aux laser had the Xtal temp of 40.88.

- I could observe the sidebands easily, with a narrower BW of the RF analizer I could see the sidebands up to the 2nd order.
  The 3rd order was not seen at all.

- The beat note had the amplitude of about -30dBm. One possibility is to amplify the signal. I wanted to use a spare channel
of the ALS/FOLL amplifier box. But it gave me rather attenuation than any amplification.
I'll look at the box tomorrow.

- Also the matching of two beams are not great. The PD also has clipping I guess. These will also be improved tomorrow

- Then the beat note will be locked at a certain frequency using PLL so that we can reduce the measurement BW more.


  11027   Sat Feb 14 00:42:02 2015 KojiUpdateGeneralRF amplifier for ALS

The RF analyzer was returned to the control room. There are two beat notes from X/Y confirmed.

I locked the arms and aligned them with ASS.

When the end greens are locked at TEM00, X/Y beat amplitudes were ~33dBm and ~17dBm. respectively.
I don't judge if they are OK or not, as I don't recall the nominal values.

  11028   Sat Feb 14 00:48:13 2015 KojiUpdateLSC3f modulation cancellation

[SUCCESS] The 3f sideband cancellation seemed worked nicely.

- Beat effeciency improved: ~30% contrast (no need for amplification)

- PLL locked

- 3f modulation sideband was seen

- The attenuation of the 55MHz modulation and the delay time between the modulation source was adjusted to
have maximum reduction of the 3f sidebands as much as allowed in the setup. This adjustment has been done
at the frequency generation box at 1X2 rack.

- The measurement and receipe for the sideband cancellation come later.

- This means that I jiggled the modulation setup at 1X2 rack. Now the modulation setup was reverted to the original,
but just be careful to any change of the sensing behavior.

- The RF analyzer was returned to the control room.

- The HEPA speed was reduced from 100% (during the action on the table) to 40%.

  11029   Sat Feb 14 19:54:04 2015 KojiSummaryLSC3f modulation cancellation

Optical Setup

[Attachment 1]

Right before the PSL beam goes into the vacuum chamber, it goes through an AR-wedged plate.
This AR plate produces two beams. One of them is for the IO beam angle/position monitor.
And the other was usually dumped. I decided to use this beam.

A G&H mirror reflects the beam towards the edge of the table.
A 45deg HR mirror brings this beam to the beat set up at the south side of the table.
This beam is S-polarlized as it directly comes from the EOM.

[Attachment 2]

The beam from the PSL goes through a HWP and some matching lenses before the combining beam splitter (50% 45deg P).
The AUX laser beam is attenuated by a HWP and a PBS. The transmitted beam from the PBS is supposed
to have P-polarization. The beam alignment is usually done at the PSL beam side.

The combined beam is steered by a HR mirror and introduced to Thorlabs PDA10CF. As the PD has small diameter
of 0.5mm, the beam needed to be focused by a strong lens.

After careful adjustment of the beam mode matching, polarization, and alignment, the beatnote was ~1Vpp for 2.5Vdc.
In the end, I reduced the AUX laser power such that the beat amplitude went down to ~0.18Vpp (-11dBm at the PD,
-18dBm at the mixer, -27dBm at the spectrum analyzer) in order to minimize nonlinearity of the RF system and
in order that the spectrum analyzer didn't need input attenuation.

Electrical Setup

[Attachment 3]

The PD signal is mixed with a local oscillator signal at 95MHz, and then used to lock the PLL loop.
The PLL loop allows us to observe the peaks with more integration time, and thus with a better signal-to-noise ratio.

The signal from the PD output goes through a DC block, then 6dB attenuator. This attenuator is added to damp reflection
and distortion between the PD and the mixer. When the PLL is locked, the dominant signal is the one at 95MHz. Without this attenuator,
this strong 95MHz signal cause harmonic distortions like 190MHz. As a result, it causes series of spurious peaks at 190MHz +/- n* 11MHz.

10dB coupler is used to peep the PD signal without much disturbing the main line. Considering we have 6dB attanuator,
we can use this coupler output for the PLL and can use the main line for the RF monitor, next time.

The mixer takes the PD signal and the LO signal from Marconi. Marconi is set to have +7dBm output at 95MHz.
FOr the image rejection, SLP1.9 was used. The minicirsuit filters have high-Z at the stop band, we need a 50Ohm temrinator
between the mixer and the LPF.

The error signal from the LPF is fed to SR560 (G=+500, 1Hz 1st-order LPF). I still don't understand why I had to use a LPF
for the locking.
As the NPRO PZT is a frequency actuator, and the PLL is sensitive to the phase, we are supposed to use
a flat response for PLL locking. But it didn't work. Once we check the open loop TF of the system, it will become obvious (but I didn't).

The actuation signal is fed to the fast PZT input of the AUX NPRO laser.

  11031   Sat Feb 14 20:37:51 2015 KojiSummaryLSC3f modulation cancellation

Experimental results

- PD response [Attachment 1]

The AUX laser temperature was swept along with the note by Annalisa [http://nodus.ligo.caltech.edu:8080/40m/8369]
It is easier to observe the beat note by closing the PSL shutter as the MC locking yields more fluctuation of the PSL
laser freuqency at low frequency. Once I got the beat note and maximized it, I immediately noticed that the PD response
is not flat. For the next trial, we should use Newfocus 1611. For the measurement today, I decided to characterize the
response by sweeping the beat frequency and use the MAXHOLD function of the spectrum analyzer.

The measured and modelled response of the PD are shown in the attachment 1. It has non-intuitive shape.
Therefore the response is first modelled by two complex pole pair at 127.5MHz with Q of 1, and then the residual was
empirically fitted with 29th polynomial of f.

- Modulation profile of the nominal setting [Attachment 2]

Now the spectrum of the PD output was measured. This is a stiched data of the spectrum between 1~101MHz and 99~199MHz
that was almost simultaneously measured (i.e. Display 1 and Display 2). The IF bandwidth was 1kHz. The PD response correction
described above was applied.

It obviously had the peaks associated with our main modulations. In addition, there are more peaks seen.
The attachment 2 breaks down what is causing the peaks.

  • Carrier: The PLL LO frequency is 95MHz. Therefore the carrier is locked at 95MHz.
  • Modulation sidebands (11/55MHz series):
    Series of sidebands are seen at the both side of the carrier. Their frequency is 95MHz +/- n * fmod  (fmod = 11.066128MHz).
    Note that the sidebands for n>10 were above 200MHz, and n<-9 (indicated in gray) were folded at 0Hz.
    With this measurement BW, the following sidebands were buried in the noise floor.
    n = -8, -12, -13, and -14, n<= -16, and n>=+7
  • Modulation sidebands for IMC and PMC (29.5MHz and 35.5MHz):
    First order sidebands for the IMC and PMC modulations of sidebands are seen at the both side of the carrier.
    Their frequency is 95MHz +/- 29.5MHz or 33.5MHz. The PMC modulation sidebands are supposed to be blocked
    by the PMC. However, due to finite finesse of the PMC, small fraction of the PMC sidebands are transmitted.
    In deed, it is comparable to the modulation depth of the IMC one.
  • RF AM or RF EMI for the main modulation and the IMC modulationand:
    If there is residual RF AM in the PSL beam associated with the IMC and main modulations, it appears as the
    peaks at the modulation frequency and its harmonics. Also EM radiation couples into this measument RF system
    also appears at these frequencies. They are seen at n * fmod  (n=1,2,4,5) and 29.5MHz.
  • Reflection/distortion or leakage from mixer IF to RF:
    The IF port of the mixer naturally has 190MHz signal when the PLL is locked. If the isolation from the IF port to the RF port
    is not enough, this signal can appear in the RF monitor signal via an imperfection of the coupler or a reflection from the PD.
    Also, if the reflecrtion/distortion exist between the PD and the mixer RF input, it also cause the signal around 190MHz.
    It is seen at 190MHz +/- n* fmod. In the plot, the peak at n=0, -1 are visible. In fact these peak were secondarily dominant
    in the spectrum when there was no 6dB attenuation in the PD line. WIth the attenuator, they are well damped and don't disturb
    the main measurment.

From the measured peak height, we are able to estimate the modulation depths for 11MHz, 55MHz, IMC modulations, as well as
the relative phase of the 11MHz and 55MHz modulation. (It is not yet done).

- 3f modulation reduction [Attachment 3]

Now, the redcution of the 3f modulation was tried. The measured modulation levels for the 11MHz and 55MHz were almost the same.
The calculation predicts that the modulation for the 55MHz needs to be 1/3 of the 11MHz one. Therefore the attenuation of 9dB and 10dB
of the modulation attenuation knob at the frequency generation box were tried.

To give the variable delay time in the 55MHz line, EG&G ORTEC delay line unit was used. This allows us to change the delay time from
0ns to 63.5ns with the resolution of 0.5ns. The frequency of 55MHz yields a phase sensitivity of ~20deg/ns (360deg/18ns).
Therefore we can adjust the phase with the precision of 10deg over 1275deg.

The 3rd-order peak at 61.8MHz was observed with measurement span of 1kHz with very narrow BW like 30Hz(? not so sure). The delay
time was swept while measuring the peak height each time. For both the atteuation, the peak height clearly showed the repeatitive dependence
with the period of 18ns, and the 10dB case gave the better result. The difference between the best (1.24e-7 Vpk) and the worst (2.63e-6 Vpk)
was more than a factor of 20.
The 3rd-order peak in the above broadband spectrum measurement was 6.38e-6 Vpk. Considering the attenuation
of the 55MHz modulation by 10dB, we were at the exact unluck phase difference.
The improvement expected from the 3f reduction (in the 33MHz signal)
will be about 50, assuming there is no other coupling mechanism from CARM to REFL33.

I decided to declare the best setting is "10dB attenuation & 28ns delay".

- Resulting modulation profile [Attachment 4]

As a confirmation, the modulation profie was measured as done before the adjustment.
It is clear that the 3rd-order modulation was buried in the floor noise. 10dB attenuation of the 55MHz modulation yields corresponding reduction of the sidebands.
This will impact the signal quality for the 55MHz series error signals, particularly 165MHz ones. We should consider to install the Teledyne Cougar amplifier
next to the EOM so that we can increase the over all modulation depth.

  11032   Sat Feb 14 22:14:02 2015 KojiSummaryLSC[HOW TO] 3f modulation cancellation

When I finished my measurements, the modulation setup was reverted to the conventional one.
If someone wants to use the 3f cancellation setting, it can be done along with this HOW-TO.

The 3f cancellation can be realized by adding a carefully adjusted delay line and attenuation for the 55MHz modulation
on the frequency generation box at the 1X2 rack.  Here is the procedure:

1) Turn off the frequency generation box

There is a toggle switch at the rear of the unit. It's better to turn it off before any cable action.
The outputs of the frequency generation box are high in general. We don't want to operate
the amplifiers without proper impedance matching in any occasion.

2) Remove the small SMA cable between 55MHz out and 55MHz in (Left arrow in the attachment 1).

According to the photo by Alberto (svn: /docs/upgrade08/RFsystem/frequencyGenerationBox/photos/DSC_2410.JPG),
this 55MHz out is the output of the frequency multiplier. The 55MHz in is the input for the amplifier stages.
Therefore, the cable length between these two connectors changes the relative phase between the modulations at 11MHz and 55MHz.

3) Add a delay line box with cables (Attachment 2).

Connect the cables from the delay line box to the 55MHz in/out connectors. I used 1.5m BNC cables.
The delay line box was set to have 28ns delay.

4) Set the attenuation of the 55MHz EOM drive (Right arrow in the attachment 1) to be 10dB.

Rotate the attenuation for 55MHz EOM from 0dB nominal to 10dB.

5) Turn on the frequency modulation box

For reference, the 3rd attachment shows the characteristics of the delay line cable/box combo when the 3f modualtion reduction
was realized. It had 1.37dB attenuation and +124deg phase shift. This phase change corresponds to the time delay of 48ns.
Note that the response of a short cable used for the measurement has been calibrated out using the CAL function of the network analyzer.

  11033   Sun Feb 15 16:20:44 2015 KojiSummaryLSC[ELOG LIST] 3f modulation cancellation

Summary of the ELOGS

3f modulation cancellation theory http://nodus.ligo.caltech.edu:8080/40m/11005

3f modulation cancellation adjustment setup http://nodus.ligo.caltech.edu:8080/40m/11029

Experiment http://nodus.ligo.caltech.edu:8080/40m/11031

Receipe for the 3f modulation cancellation http://nodus.ligo.caltech.edu:8080/40m/11032

Modulation depth analysis http://nodus.ligo.caltech.edu:8080/40m/11036

  11035   Mon Feb 16 00:08:44 2015 KojiSummaryLSC[ELOG LIST] 3f modulation cancellation

This KTP crystal has the maximum allowed RF power of 10W (=32Vpk) and V_pi = 230V. This corresponds to the maximum allowed
modulation depth of 32*Pi/230 = 0.44. So we probably can achieve gamma_1 of ~0.4 and gamma_2 of ~0.13. That's not x3 but x2,
so sounds not too bad.

Then Kiwamu's triple resonant circuit LIGO-G1000297-v1 actually shows the modulation up to ~0.7. Therefore it is purely an issue
how to deliver sufficient modulation power. (In fact his measurement shows some nonlinearity above the modulation depth of ~0.4
so we should keep the maximum power consumption of 10W at the crystal)

This means that we need to review our RF system (again!)

- Review infamous crazy attn/amp combinations in the frequency generation box.
- Use Teledyne Cougar ampilfier (A2CP2596) right before the triple resonant box. This should be installed closely to the triple resonant box in order to
minimize the effects of the reflection due to imperferct impedance matching.
- Review and refine the triple resonant circuit - it's not built on a PCB but on a universal board. I think that we don't need triple
resonance, but double is OK as the 29.5MHz signal is small.

We want +28V supply at 1X1 for the Teledyne amp and the AOM driver. Do we have any unused Sorensen?

  11036   Mon Feb 16 01:45:12 2015 KojiSummaryLSCmodulation depth analysis

Based on the measured modulation profiles, the depth of each modulation was estimated.
Least square sum minimization of the relative error was used for the cost function.
-8th, -12th~-14th, n=>7th are not included in the estimation for the nominal case.
-7th~-9th, -11th~-15th, n=>7th are not included in the estimation for the 3f reduced case.

Nominal modulation

m_f1 = 0.194
m_f2 = 0.234
theta_f1f2 = 41.35deg
m_IMC = 0.00153

3f reduced modulation

m_f1 = 0.191
m_f2 = 0.0579
theta_f1f2 = 180deg
m_IMC = 0.00149

(Sorry! There is no error bars. The data have too few statistics...)

  11038   Mon Feb 16 03:10:42 2015 KojiUpdateLSCALS fool measured decoupling TF

Wonkey shape: Looks like a loop supression. Your http://nodus.ligo.caltech.edu:8080/40m/11016 also suggests it too, doesn't it?

  11044   Tue Feb 17 16:44:04 2015 KojiUpdateLSCDelay line installed again

For tonight's experiment, I re-installed the delay line cable and changed the attenuation to 10dB for the 55MHz modulation.

I quickly locked the PLL and checked that the modulation is the ratio of the field strength between the worst (19ns) and best
case (28ns) is 31dB, that is ~35 times reduction.

  11045   Tue Feb 17 19:49:51 2015 KojiUpdateLSCDelay line un-installed again

The modulation setting was reverted.
Demod phase for REFL11/33/55/165 and AS55 were reverted to the previous numbers too.

  11048   Wed Feb 18 19:06:40 2015 KojiUpdateLSCALS Fool impulse response

  11059   Mon Feb 23 21:57:13 2015 KojiUpdateLSCDelay line installed again (experiment, round 1)

Last Wednesday we tried PRMI 3f modulation cancellation. Under the 3f modulation cancellation, the PRMI could not be locked
with REFL signals, and the PRCL signal was just barely sufficient to lock PRCL with help of AS55Q MICH.

- The PRCL signal level in REFL33 was reduced by factor of 20 compared with the conventional modulation setting.
=> The 3f modulation cancellation does not chage the level of 11/22MHz sidebands, it is expected that REFL33 signal
has no significant change of the signal level. But it does.  If we change the relative phase between the modulations
at 11 and 55MHz, the signal level is recovered by factor of 5. Therefore something related to 55MHz modulation
(55MHz x 22MHz, or 44MHz x 11MHz) was contributing more than -11MHzx22MHz.

- Under the 3f demodulation cancellation, MICH signal in the REFL ports were extremely weak and there was
no hope to use it for any feedback control.

- WIth the PRMI locking by REFL33->PRCL and AS55Q->MICH, the sensing matrix was measured. All of the REFL
ports however, showed extremely degenerate sensing matrix between MICH and PRCL.

This was enough confusing to us, and we didn't draw any useful information from these. Here are some ideas to
investigate what is happening in out optical and electrical system.

- One approach is to use as simple optical setup as possible to inspect our sensing systems. For example,
we may want to try PRX/PRY/XARM/YARM cavities to check the functions of the REFL diodes and qualitatively characterize
the sensing chain (Optical gain [W/m], noise level, demodulation phase) so that we can compare these with
an interferometer seinsing model.

- Another approach is to change the mdulation setting more freely and empirically try to find the characteristic
of our optical/electrical systems. e.g. change the relative modulation phase and/or 55MHz attenuation, and try to understand
how 11-22, 11-44, 22-55, 0-33 pairs are contributing the signal.

  11066   Wed Feb 25 12:16:27 2015 KojiUpdateLSCDelay line re-installed, measurements round 2

WHAT? WHAT? WHAT? It's obviously opposite.

If the reflectivity of the front mirror is fixed (=PRM reflectivity), the finesse increases when the reflectivity of the end
mirror (=Compond mirror reflectivity) increases. i.e. 11MHz has higher finesse, 55MHz has lower finesse.

{\cal F} = \frac{\pi \sqrt{r_{\rm PRM} r_{\rm COM}}}{1-r_{\rm PRM} r_{\rm COM}}

If the reflectivity of the front mirror is fixed, the amplitude gain of the cavity is higher when the reflectivity of the end mirror increases. i.e. 11MHz has higher gain, 55MHz has lower gain

g_{\rm PRM} = \frac{t_{\rm PRM}}{1-r_{\rm PRM} r_{\rm COM}}


Our Schnupp asymmetry is small (3.9cm, IIRC), so the transmission of the 11MHz signal out the dark port is small.  This means that the finesse of the PRC for 11MHz isn't so huge.  On the other hand, since 55MHz is a higher frequency, the transmission out the dark port is larger and is a closer match to the PRM transmission, so the finesse of the PRC for 55MHz is higher. 


  11074   Thu Feb 26 01:53:35 2015 KojiUpdateLSCModelled effect of relative modulation phase

Ok... This is what I was afraid of, and it seems true.
i.e. the relation ship of the modulations for the 3f cancellation is making the PRCL signals cancel each other.

It agrees with Anamaria's analysis that 11x44 is the strongest component in aLIGO 27MHz signal.
In fact,

00x33 has the order of \frac{m_1^2 m_2}{16}+\frac{m_1^3}{48}

11x22 has the order of \frac{m_1^3}{16}

11x44 has the order of \frac{m_1^2 m_2}{8}

22x55 has the order of \frac{m_1^2 m_2}{16}

Therefore 11x44 is inherently the strongest contribution at 33MHz.
(And then, of couse, the signal amplitudes have additional dependences on the reflectivity
and the gain of the IFO at each freq)

If we believe this result, it may be difficult to exploit the benefit of the signals under the 3f cancellation.
We probably have to go back to the original idea of cancelling the 3f modulation by adding 3f modulation.
(i.e. Produce 33MHz signal by freq tripling, add this signal to Kiwamu's box to elliminate 3f.)

  11117   Sun Mar 8 00:05:37 2015 KojiConfigurationLSCCARM and DARM on RF signals!!!!!!!!!!!!!!!!!!!!

Exciting! How long was it?

  11129   Tue Mar 10 19:59:13 2015 KojiFrogsCamerasMessage from the IFO

  11134   Wed Mar 11 19:15:03 2015 KojiSummaryLSCROUGH calibration of the darm spectrum during the full PRFPMI lock

I made very rough calibration of the DARM spectra before and after the transition for the second lock on Mar 8.

The cavity pole (expected to be 4.3kHz) was not compensated. Also the servo bump was not compensated.

[Error calibration]

While the DARM/CARM were controlled with ALS, the calibration of them are provided by the ALS phase tracker calibration.
i.e 1 degree = 19.23kHz

This means that the calibration factor is

DARM [deg] * 19.23e3 [Hz/deg] / c [m Hz] * lambda [m] * L_arm [m]
= DARM* 19.23e3/299792458*1064e-9*38.5 = 2.6e-9 *DARM [m]

[Feedback calibration]

Then, the feedback signal was calibrated by the suspension response (f=1Hz, Q=5)
so that the error and feedback signals can match at 100Hz.

This gave me the DC factor of 5e-8.

The spectra at 1109832200 (ALS only, even not on the resonance) and 1109832500 (after DARM/CARM transitions) were taken.
Jenne said that the whitening filters for AS55Q was not on.

  11135   Wed Mar 11 19:48:25 2015 KojiUpdateGeneralFOL troubleshooting

There is a frequency counter code written by the summer student.
The code needed some cleaning up.
It's still there in /opt/rtcds/caltech/c1/scripts/FOL as armFC.c

This code did not provide unified way to send commands to the FCs.
Therefore I made a code to change the frequency range of the FCs
by removing unused variables and instructions, adding more comments,
adding reasonable help messages and trouble shooting feedbacks.

Obviously these codes only run on domenica (raphsberry Pi host)


change_frange : change the freq range of the frequency counter UFC-6000

Usage: ./change_frange DEVICE VALUE
    DEVICE: '/dev/hidraw0' for Xarm, '/dev/hidraw1' for Yarm
0 - automatic
1 -    1MHz to   40MHz
2 -   40MHz to  190MHz
3 -  190MHz to 1400MHz
4 - 1400MHz to 6000MHz

  11137   Thu Mar 12 11:57:38 2015 KojiUpdateGeneralFOL troubleshooting

BTW, during this trouble shoot, we looked at the IR beatnote spectrum between the Xend and the PSL.
It showed a set of sidebands at ~200kHz, which is the modulation frequency.
There was another eminent component present at ~30kHz.
I'm afraid that there is some feature like large servo bump, a mechanical resonance, or something else, at 30kHz.

We should check it. Probably it is my job.

  11151   Fri Mar 20 13:29:33 2015 KojiUpdateIOOWaking up the IFO

If the optics moved such amount, could you check the PD alignment once the optics are aligned?

  11171   Wed Mar 25 18:27:34 2015 KojiSummaryGeneralSome maintainance

- I found that the cable for the AS55 LO signal had the shielding 90% broken. It was fixed.

- The Mon5 monitor in the control room was not functional for months. I found a small CRT down the east arm.
It is now set as MON5 showing the picture from cameras. Steve, do we need any safety measure for this CRT?

  11173   Wed Mar 25 18:48:11 2015 KojiSummaryLSC55MHz demodulators inspection

[Koji Den EricG]

We inspected the {REFL, AS, POP}55 demodulators.

Short in short, we did the following changes:

- The REFL55 PD RF signal is connected to the POP55 demodulator now.
Thus, the POP55 signals should be used at the input matrix of the LSC screens for PRMI tests.

- The POP55 PD RF signal is connected to the REFL55 demodulator now.

- We jiggled the whitening gains and the whitening triggers. Whitening gains for the AS, REFL, POP PDs are set to be 9, 21, 30dB as before.
However, the signal gain may be changed. The optimal gains should be checked through the locking with the interferometer.

- Test 1

Inject 55.3MHz signal to the demodulators. Check the amplitude in the demodulated signal with DTT.
The peak height in the spectrum was calibrated to counts (i.e. it is not counts/rtHz)
We check the amplitude at the input of the input filters (e.g. C1:LSC-REFL55_I_IN1). The whitening gains are set to 0dB.
And the whitening filters were turned off.

f_inj = 55.32961MHz -10dBm
REFL55I @999Hz  22.14 [cnt]
REFL55Q @999Hz  26.21 [cnt]

f_inj = 55.33051MHz -10dBm
REFL55I @ 99Hz  20.26 [cnt]  ~200mVpk at the analog I monitor
REFL55Q @ 99Hz  24.03 [cnt]

f_inj = 55.33060MHz -10dBm
REFL55I @8.5Hz  22.14 [cnt]
REFL55Q @8.5Hz  26.21 [cnt]

f_inj = 55.33051MHz -10dBm
AS55I   @ 99Hz 585.4 [cnt]
AS55Q   @ 99Hz 590.5 [cnt]   ~600mVpk at the analog Q monitor

f_inj = 55.33051MHz -10dBm
POP55I  @ 99Hz 613.9 [cnt]   ~600mVpk at the analog I monitor
POP55Q  @ 99Hz 602.2 [cnt]

We wondered why the REFL55 has such a small response. The other demodulators seems to have some daughter board. (Sigg amp?)
This maybe causing this difference.


- Test 2

We injected 1kHz 1Vpk AF signal into whitening board. The peak height at 1kHz was measured.
The whitening filters/gains were set to be the same condition above.

f_inj = 1kHz 1Vpk
REFL55I 2403 cnt
2374 cnt
AS55I   2374 cnt
AS55Q   2396 cnt
POP55I  2365 cnt
  2350 cnt

So, they look identical. => The difference between REFL55 and others are in the demodulator.

  11174   Wed Mar 25 21:44:20 2015 KojiUpdateLSCIFO recovery / PRFPMI locking activity

[Koji, Den]

- Aligned the arms with ASS. It had alot of offset accumulated. We offloaded it to the suspension.

- We could lock the PRMIsb with the new setup.
PRCL: REFL165I (-14deg, analog +9dB)) -0.1, Locking FM4/5, Triggered FM 2
MICH: REFL165Q (-14deg, analog +9dB) -1.5, Locking FM4/5, Triggered FM2/6/9

- Demod phases at REFL were adjusted such that PRCL in Q signals were minimized :
REFL165 -80deg => -14deg
POP55 -63deg
REFL11 +164 => +7
REFL33 +136 => +133

Note: analog gains: REFL11: +18dB,  REFL33: +30dB, POP55: +12dB, REFL165: +9dB

- Try some transition between REFL signals to check the signal quality.
Measure TFs between the REFL signals

PRCL gain
REFL11I/REFL165I = +58
REFL33I/REFL165I = +8.5
POP55I /REFL165I = -246

MICH gain
REFL11Q/REFL165Q = +11
REFL33Q/REFL165Q = -1.5
POP55Q /REFL165Q = +280

- This resulted us to figure out the relationships of the numbers in the input matrix 

REFL55I/Q -4e-3/4e-3
REFL165I/Q 1.0/1.0 (reference)
REFL11I/Q  0.02/0.1
REFL33I/Q +0.12/-0.7

Full locking trial

Arm locked -> ALS -> Arm offset locked
PRMI locking
REFL165 phase tuned -110deg
PRCL gain -0.1 / MICH gain -2

We needed script editing.
Previous script saved in: /opt/rtcds/caltech/c1/scripts/PRFPMI/carm_cm_up_BACKUP.sh

- PRMI gain setting (input matrix & servo gain)
- CARM/DARM transition setting (see below)

The current CARM/DARM transition procedure:

- CM REFL1 gain is set to be -32
- CARM_B is engaged and the gain is ramped from 0 to +2.5
- Turn on FM7 (integrator)
- MC IN2 (AO path) engaged
- MC IN2 gain increased from -32 to -21

- DARM_B is engaged and the gain is ramped from 0 to +0.1
- Turn on FM7 (integrator)

- CM REFL1 Gain is increased from -32 to -18
- Ramp down CARM A gain to 0

- DARM_B gain is incrased to 0.37. At the same time DARM_A gain is reduced to 0

We succeeded to make the transition several times in the new setting.

- But later the transition got hard. We started to see big jump of the arm trans (TRX/Y 50->100) at the CARM transition.

- We tested the PRCL transition from 165MHz to 55MHz. 55MHz (i.e. POP55 which is REFL55PD) looks alot better now.

- ~1:30 The PMC was realigned. This  increased PMC_TRANS about 10%. This let the Y arm trans recover ~1.00 for the single arm locking

- Decided to end around 3:00AM

  11179   Fri Mar 27 14:47:57 2015 KojiUpdateLSCals->pdh transition, prcl on 1f, alignment

Jenne and I interviewd Den this afternoon to make the things clear

- His "duty cycle" is not about the lengths of the lock stretch. He saids, the transition success probability is improved.

- For this improvement, the CARM transition procedure was modified to include turning on 1:20 (Z1P20) filter in CARM_A (i.e. ALS) once CARM_B (i.e. RF) dominates the loop in all frequency.

- I think this transition can be summarized like the attachment. At STEP4, the integration of the ALS is reduced. This actually does not change the stability of the servo as the servo stability is determined by the stability of the CARM_B loop. But this does further allow CARM_B to supress the noise. Or in other word, we can remove the noise coming from the CARM_A loop.

- The POP22 issue: Jenne has the trigger signal that is immune to this issue by adding some amount of POPDC for the trigger.
We can avoid the trigger issue by this technique. But if the issue is due to the true optical gain fluctuation, this may mean that the 11MHz optical gain is changing too much. This might be helped by PRC angular feedforward or RF 22MHz QPD at POP.

  11180   Fri Mar 27 20:32:17 2015 KojiSummaryLSCLocking activity

- Adjutsed the IMC WFS operating point. The IMC refl is 0.42-0.43.

- The arms are aligned with ASS

- The X arm green was aligned with ASX. PZT offsets slides were adjusted to offload the servo outputs.

- I tried the locking once and the transition was successfull. I even tried the 3f-1f transition but the lock was lost. I wasn't sure what was the real cause.

I need to go now. I leave the IFO at the state that it is waiting for the arms locked with IR for the full locking trial.

  11183   Tue Mar 31 03:02:44 2015 KojiUpdateLSCSome locks

Assuming the carrier mode in PRC is stable and the SB is the one moving, can we just use the POP DC QPD to control PRM?

Can we plot the arm power trend for multiple locks to see if it is associated with any thermal phenomenan in the IFO?
They should be able to fit with an exp + DC.

  11245   Fri Apr 24 21:31:20 2015 KojiSummaryCDSautomatic mxstream resetting

We were too much annoyed by frequent stall of mxstream. We'll update the RCG when time comes (not too much future).

But for now, we need an automatic mxstream resetting.

I found there is such a script already.


So this script was registered to crontab on megatron.
It is invoked every 5 minutes.

# Auto MXstream reset when it fails
0,5,10,15,20,25,30,35,40,45,50,55 * * * * /opt/rtcds/caltech/c1/scripts/cds/autoMX >> /opt/rtcds/caltech/c1/scripts/cds/autoMX.log

  11248   Sat Apr 25 03:32:45 2015 KojiUpdateASCBroken Xass?

I spent a day to fix the XARM ASS, but no real result. If the input of the 6th DOF servo is turned off, the other error signals are happy
to be squished to around their zeros. So this gives us some sort of alignment control. But obviously a particular combination of the
misalignment is left uncontrolled.

This 6th DOF uses BS to minimize the dither in ITMX yaw. I tired to use the other actuators but failed to have linear coupling between
the actuator and the sensor.

During the investigation, I compared TRX/TRY power spectra. TRX had a bump at 30Hz. Further investigation revealed that the POX/POY
had a big bump in the error signals. The POX/POY error signals between 10-100Hz were coherent. This means that this is coming from
the frequency noise stabilized with the MC. (Is this frequency noise level reasonable?)

The mysterious discovery was that the bump in the transmission exist only in TRX. How did the residual frequency noise cause
the intensity noise of the transmission? One way is the PDH offset.

Anyway, Rana pointed out that IMC WFS QPDs had large spot offsets. Rana went to the AS table and fixed the WFS spot centering.
This actually removed the bump in TRX although we still don't know the mechanism of this coupling.

The bump at 30Hz was removed. However, the ASS issue still remains.

  11312   Tue May 19 17:03:34 2015 KojiUpdateCDSMXstream restart script working (beta)

AutoMX is resetting mx_stream every 5 minutes. Basically everytime AutoMX is called,
it resets mx_stream. Is the mx_stream stalling such often? Or the script is detecting false alerms?

> tail -200 /opt/rtcds/caltech/c1/scripts/cds/autoMX.log

Tue May 19 16:43:01 PDT 2015
LSC - FB bad. Runnning restart:
 * Stopping mx_stream ...                                                 [ ok ]
 * Starting mx_stream ...                                                 [ ok ]
Connection to c1sus closed.
 * Stopping mx_stream ...                                                 [ ok ]
 * Starting mx_stream ...                                                 [ ok ]
Connection to c1lsc closed.
 * Stopping mx_stream ...                                                 [ ok ]
 * Starting mx_stream ...                                                 [ ok ]
Connection to c1ioo closed.
 * Stopping mx_stream ...                                                 [ ok ]
 * Starting mx_stream ...                                                 [ ok ]
Connection to c1iscex closed.
 * Stopping mx_stream ...                                                 [ ok ]
 * Starting mx_stream ...                                                 [ ok ]
Connection to c1iscey closed.
Tue May 19 16:48:02 PDT 2015
LSC - FB bad. Runnning restart:
 * Stopping mx_stream ...                                                 [ ok ]
 * Starting mx_stream ...                                                 [ ok ]
Connection to c1sus closed.
 * Stopping mx_stream ...                                                 [ ok ]
 * Starting mx_stream ...                                                 [ ok ]
Connection to c1lsc closed.
ssh_exchange_identification: read: Connection reset by peer
 * Stopping mx_stream ...                                                 [ ok ]
 * Starting mx_stream ...                                                 [ ok ]
Connection to c1iscex closed.
 * Stopping mx_stream ...                                                 [ ok ]
 * Starting mx_stream ...                                                 [ ok ]
Connection to c1iscey closed.
Tue May 19 16:53:01 PDT 2015
LSC - FB bad. Runnning restart:
 * Stopping mx_stream ...                                                 [ ok ]
 * Starting mx_stream ...                                                 [ ok ]
Connection to c1sus closed.
 * Stopping mx_stream ...                                                 [ ok ]
 * Starting mx_stream ...                                                 [ ok ]
Connection to c1lsc closed.
 * Stopping mx_stream ...                                                 [ ok ]
 * Starting mx_stream ...                                                 [ ok ]
Connection to c1ioo closed.
 * Stopping mx_stream ...                                                 [ ok ]
 * Starting mx_stream ...                                                 [ ok ]
Connection to c1iscex closed.
 * Stopping mx_stream ...                                                 [ ok ]
 * Starting mx_stream ...                                                 [ ok ]
Connection to c1iscey closed.

  11323   Sun May 24 14:45:02 2015 KojiHowToGeneralHow to launch StripTools at specified locations

LLO Operator Tips:

koji.arai@cr9:/opt/rtcds/userapps/trunk/asc/l1/scripts/initial_alignment$ cat autostart_strips.sh 


# Baffle window setup 1500x480

StripTool -xrm 'StripTool.StripGraph.geometry:1500x470+0+24' /opt/rtcds/userapps/trunk/asc/l1/scripts/initial_alignment/baffle_pd.stp &
sleep 1

# DC signals setup

StripTool -xrm 'StripTool.StripGraph.geometry:1500x470+0+470' /opt/rtcds/userapps/trunk/asc/l1/scripts/initial_alignment/dc_signals.stp &
sleep 1

# WFS prx mich sry setup

StripTool -xrm 'StripTool.StripGraph.geometry:1500x470+0-24' /opt/rtcds/userapps/trunk/asc/l1/scripts/initial_alignment/wfs_prx_mich_sry.stp &
sleep 1


  11332   Thu May 28 17:00:04 2015 KojiUpdateIOOFSS SLOW not engaged: is this intentional?

I found that FSS SLOW servo is not engaged. Is this intentional test to keep the NPRO temp constant?
This is making the FSS Fast unhappy (~ -7.5V right now).

  11334   Thu May 28 21:10:46 2015 KojiUpdateGreen LockingALS-X noise hunting

I have been looking at the X-end ALS setup.
I was playing with the control bandwidth to see the effect to the phase tracker output (i.e. ALS err).
For this test the arm was locked with the IR and the green beat note was used as the monitor.

From the shape of the error signal, the UGF of the green PDH was ~10kHz. When I increased the gain
to make the servo peaky, actually the floor level of the ALS err became WORSE. I did not see any improvement
anywhere. So, high residual error RMS cause some broadband noise in the ALS??? This should be checked.
Then when the UGF was lowered to 3kHz, I could see some bump at 3kHz showed up in the ALS error.
I didn't see the change of the PSD below 1kHz. So, more supression of the green PDH does not help
to improve the ALS error?

Then, I started to play with the phase tracker. It seems that someone already added the LF booster
to the phase tracker servo. I checked the phase tracker error  and confirmed it is well supressed.
Further integrator does not help to reduce the phase tracker error.

For the next thing I started to change the offset of the phase tracker. This actually changes
the ALS error level!
The attached plot shows the dependence of the ALS error PSD on the phase tracker
output. At the time of this measurement, the offset of -10 exhibited the best noise level.
This was, indeed, factor of 3~5 improvement compared to the zero offset case below 100Hz.

I'm afraid that this offset changes the beat frequency as I had the best noise level at the offset of -5
with a different lock streatch. We should look at this more carefully. If the beat freq changes the offset,
this give us another reason to fix the beat frequency (i.e. we need the frequency control loop.

= Today's ALSX error would have not been the usual low noise state.
We should recover the nominal state of the ALS and make the same test =

  11337   Fri May 29 12:49:53 2015 KojiUpdateComputer Scripts / ProgramsChiara Backup Hiccup

In fact, the file access is supposed to be WAY faster now than in the RAID case.

As noted in ELOG 9511, it was SCSI-2(or 3?) that had ~6MB/s thruput. Previously the backup took ~2hours.
This was improved to 30min by SATA HDD on llinux1.

I am looking at /opt/rtcds/caltech/c1/scripts/backup/rsync.backup.cumlog

In fact, this "30-min backup" was true until the end of March. After that the backup is taking 1h~1.5h.

This could be related to the recent NFS issue?

  11338   Fri May 29 15:12:39 2015 KojiUpdateComputer Scripts / ProgramsChiara Backup Hiccup

Actual data

  11353   Thu Jun 11 19:40:59 2015 KojiUpdateVACVacuum comp. rebooted

The serial connections to the vacuum gauges were recovered by rebooting c1vac1 and c1vac2.

Steve claimed that the vacuum screen had showed "NO COMM" at the vacuum pressure values.
The epics connection to c1vac was fine. We could logged in to c1vac1 with telnet too although c1vac2 had no response.

After some inspection, we decided to reboot the slow machines. Steve manually XXXed YYY valves (to be described)
to prepare for any possible unwanted switching. Initially Koji thought only c1vac2 can be rebooted. But it was wrong.
If the reset button is pushed, all of the modules on the same crate is reset. So everything was reset. After ~3min we still
don't have the connection to c1vac1 restored. We decided to another reboot. This time I pushed c1vac1 reset button.
After waiting about two minutes, the ADCs started to show green lights and the switch box started scanning.
We recovered the telnet connection to c1vac1 and epics functions. c1vac2 is still note responding to telnet, and
the values associated with c1vac2 are still blank.

Steve restored the valves and everything was back to normal.

  11386   Wed Jul 1 09:33:31 2015 KojiUpdateGeneralShutters closed, watch dogs disabled for the RCG upgrade

I closed the PSL/GREEN shutters and shut off the LSC feedback/SUS watch dogs at 9AM PDT, to allow Jamie to start his disruptive work.

  11394   Tue Jul 7 23:26:19 2015 KojiUpdateCDSAttempt to list CDS issues

As Jamie succeded to realize somewhat workable condition of the 40m CDS, I tried to list the obvious CDS issues so that we can attack them one by one.

  1. c1cal is constantly time-outing now (t>60usec). c1sus is close to it (t=56~57us)
  2. We should check the trends of the CPU meters ("C1:FEC-**_CPU_METER"). In fact this should be listed in the summary pages in a new CDS tab.
  3. Probably this is related to 1): c1lsc is constantly showing IPC error (bit0 = shmem). C1LSC_IPC_STATUS.adl is telling that this is coming from the IPC error between c1lsc and c1cal. ("C1:CAL-LSC_SENSMAT_OSC_****"). This information is found by opning C1LSC_GDS_TP.adl screen and click RT NET STAT button next to the IPC error status.
  4. We wonder how the RFM access is accelerated or decelerated by this upgrade.
  5. We need tests to see if the time delays of the models/IPCs are still reasonable.
  6. LSC Overviw screen has a small digest of the CDS status. Now there are many white boxes that correspond to the channels "C1:FEC-**_DIAG1".
  7. All realtime systems have default (0 or 1) epics channel values (i.e. gains, FM switches, matrices, etc). Need burtrestores.
  8. I tried to burtrestore the models but burtgooey indicated there are some errors.
  9. Detailed check of the snapshot files comparing snapshot files in /opt/rtcds/caltech/c1/burt/autoburt/snapshots/2015/Jul/7/19:07 and /opt/rtcds/caltech/c1/burt/autoburt/snapshots/2015/Jun/1/19:07 :
    • c1alsepics shows bunch of volatile channels to be snapshot. It seems that all of the static epics channels are missing in the snapshot file. Is this related to the current omission of the slow data acquisition? => No actually this must be the modification of the ALS model to accommodate the ALS in the LSC model for the new ALS setup.
    • c1lscepics was checked indeed slow channels were properly snapshot. So what was the problem in burting???
    • I made a simple csh script to restore the snapshots one by one while collecting the error messages.
      This script is located as /users/koji/150707/burtrevert.sh
    • #!/bin/csh
      echo 'This script restores all of the snapshot files found in' $argv[1] '.'
      echo 'Are you sure? y/n'

      set ans = $<

      set ANS = `echo $ans | tr "[:upper:]" "[:lower:]" `
      if ($ANS == y) then
          foreach fname ($argv[1]/*epics.snap)
          echo ''
          echo '#################################'
          echo $fname
          echo '#################################'

              burtwb -f $fname
          echo "exiting..."
    •  Now I ran the command
      ./burtrevert.sh /opt/rtcds/caltech/c1/burt/autoburt/snapshots/2015/Jun/1/19:07 &>burt.log
      This lists up the missing channels. The zipped log is attached to this entry.
    • Burting old snapshot always crashes the RT process "c1sus" (not the c1sus host). If I use the newly generated snapshot today,
      the process does not crash. The process halts at the cycle time of 74us (>60us). I left the process crashed so that we can take a new snapshot with the matrix numbers filled. Once we have the correct snapshot, we don't need to worry about this crash. Let's see.
    • c1sus still crashes with the new burt file. Theremust be a trigeer that makes the model frozen. We need to split the burtfile into pieces
      to figure out which line causes the halt.
  11399   Thu Jul 9 16:39:03 2015 KojiConfigurationGeneralHow to set up your own summary page environment on the LDG cluster

Here is the summary of my investigation how to set up my own "summary page" environment on the LDG (LIGO Data Grid) cluster.

Here all albert.einstein must be replaced with your own LIGO.ORG user name.

1. Obtain LDAS cluster account

Run the following from any of the terminal and use your LIGO.ORG credential
ssh albert.einstein@ssh.ligo.org
You will be suggested to visit a particular web site. Fill the form on the web site and wait for the approval e-mails.

2. Use LDG SSH login portal

Once you received the approval of the account, you should be able to log in to the system. Type the following command again from your local terminal
ssh albert.einstein@ssh.ligo.org
You are asked to select the site and machines. Select 2- CIT and b. ldas-pcdev1, c. ldas-pcdev2, or d. ldas-pcdev3.

3. Setup bash environment

Setting up the python library path is very important for the proper processing.

Here is my setup for .bash_profile

# .bash_profile
# Get the aliases and functions
if [ -f ~/.bashrc ]; then
    . ~/.bashrc

if [ -f ~/.profile ]; then
        . ~/.profile

# User specific environment and startup programs
export PATH

# So that ssh will work, take care with X logins - see .xsession
[[ -z $SSH_AGENT_PID && -z $DISPLAY ]] &&
  exec -l ssh-agent $SHELL -c "bash --login"

and .bashrc

# .bashrc

# Source global definitions
if [ -f /etc/bashrc ]; then
    . /etc/bashrc

# Set Python environment (based on gpwy-env script)

# clean path environment variable of duplicate entries
cleanpath() {
    if [[ -z "$1" ]]; then
    # map to local variable
    local badpath=$(eval echo \$$1)
    # remove duplicates
    badpath="$(echo "${badpath}" | awk -v RS=':' -v ORS=":" '!a[$1]++')"
    # remove trailing colon
    # reset variable and export
    eval $1=${badpath}
    eval export $1

# set PATH
cleanpath PATH
cleanpath PYTHONPATH


The order of cleanpath and PYTHONPATH= is important as we want to use the local library installation before anything kicks in.

4. Install required Python libraries

Run the following lines with this order so that they are installed in your "~/local"

# PIP installation
wget https://bootstrap.pypa.io/get-pip.py
python get-pip.py --user
# numpy, scipy, distribute, matplotlib, astropy, importlib installation
pip install numpy --upgrade --user
pip install scipy --upgrade --user
pip install distribute --upgrade --user
pip install matplotlib --user --upgrade
pip install astropy --upgrade --user
pip install importlib --user --upgrade

# We need to use dev branch of gwpy to run gwsumm propery
cp -r /home/detchar/opt/gwpysoft/lib/python2.6/site-packages/gwpy* ~/.local/lib/python2.6/site-packages/

# gwsumm installation
pip install --user git+https://github.com/gwpy/gwsumm

5. Setup summary pages for the 40m

Copy summary page setting from Max's directory.

cp -r ~max.isi/summary ~/

And make temporary directory for the summary pages.

mkdir /usr1/albert.einstein/summary

6. Modify typos in gw_summary_custon

Use your own editor to fix typos

emacs ~/summary/bin/gw_daily_summary_custom

replace max.isi to albert.einstein
change summary40m -> summary

Now the installation is done. From here, the description is for the routine procedure.

7. Run your summary page code

Run Kerberos authentication
kinit albert.einstein@LIGO.ORG

Run a summary page code for a specific date (e.g. for Jul 1st, 2015)
bash ${HOME}/summary/bin/gw_daily_summary_custom --day 20150701

The result can be checked under


Rerun a code for a specific page. This requires the page structure already exists.
The red texts should be modified depending on what ini file you want to run for what day.

/home/albert.einstein/.local/bin/gw_summary day --on-segdb-error warn --verbose  --output-dir . --multi-process 20 --no-html  --ifo C1 --archive C1EVE 20150630  --config-file /mnt/qfs2/albert.einstein/public_html/summary/etc/defaults.ini,/mnt/qfs2/albert.einstein/public_html/summary/etc/c1eve.ini

This command can actually be found in

8. Some useful command

To check which python library is used
python -c 'import gwpy; print gwpy.__file__'

To list installed python libraries and versions
pip list

This should return the list like the following.

astropy (1.0.3)
gwpy (0.1b1.dev121)
gwsumm (0.0.0.dev854)
matplotlib (1.4.3)
numpy (1.9.2)
scipy (0.15.1)



  11461   Wed Jul 29 21:40:39 2015 KojiSummaryCDSStatus of the frame data syncing

The trend data hasn't been synced with LDAS since Jul 27 5AM local.


controls@nodus|minute > pwd
controls@nodus|minute > ls -l 11222 | tail
total 590432
-rw-r--r-- 1 controls controls 35758781 Jul 29 11:59 C-M-1122228000-3600.gwf
-rw-r--r-- 1 controls controls 35501472 Jul 29 12:59 C-M-1122231600-3600.gwf
-rw-r--r-- 1 controls controls 35296271 Jul 29 13:59 C-M-1122235200-3600.gwf
-rw-r--r-- 1 controls controls 35459901 Jul 29 14:59 C-M-1122238800-3600.gwf
-rw-r--r-- 1 controls controls 35550346 Jul 29 15:59 C-M-1122242400-3600.gwf
-rw-r--r-- 1 controls controls 35699944 Jul 29 16:59 C-M-1122246000-3600.gwf
-rw-r--r-- 1 controls controls 35549480 Jul 29 17:59 C-M-1122249600-3600.gwf
-rw-r--r-- 1 controls controls 35481070 Jul 29 18:59 C-M-1122253200-3600.gwf
-rw-r--r-- 1 controls controls 35518238 Jul 29 19:59 C-M-1122256800-3600.gwf
-rw-r--r-- 1 controls controls 35514930 Jul 29 20:59 C-M-1122260400-3600.gwf


LDAS Minute trend:

[koji.arai@ldas-pcdev3 C-M-11]$ pwd
[koji.arai@ldas-pcdev3 C-M-11]$ ls -l | tail
-rw-r--r-- 1 1001 1001 35488497 Jul 26 19:59 C-M-1121997600-3600.gwf
-rw-r--r-- 1 1001 1001 35477333 Jul 26 21:00 C-M-1122001200-3600.gwf
-rw-r--r-- 1 1001 1001 35498259 Jul 26 21:59 C-M-1122004800-3600.gwf
-rw-r--r-- 1 1001 1001 35509729 Jul 26 22:59 C-M-1122008400-3600.gwf
-rw-r--r-- 1 1001 1001 35472432 Jul 26 23:59 C-M-1122012000-3600.gwf
-rw-r--r-- 1 1001 1001 35472230 Jul 27 00:59 C-M-1122015600-3600.gwf
-rw-r--r-- 1 1001 1001 35468199 Jul 27 01:59 C-M-1122019200-3600.gwf
-rw-r--r-- 1 1001 1001 35461729 Jul 27 02:59 C-M-1122022800-3600.gwf
-rw-r--r-- 1 1001 1001 35486755 Jul 27 03:59 C-M-1122026400-3600.gwf
-rw-r--r-- 1 1001 1001 35467084 Jul 27 04:59 C-M-1122030000-3600.gwf


  11465   Thu Jul 30 11:47:54 2015 KojiSummaryCDSStatus of the frame data syncing

Today it was synced at 5AM but that was all.


controls@nodus|minute > pwd
controls@nodus|minute > ls -l 11222|tail
-rw-r--r-- 1 controls controls 35521183 Jul 29 21:59 C-M-1122264000-3600.gwf
-rw-r--r-- 1 controls controls 35509281 Jul 29 22:59 C-M-1122267600-3600.gwf
-rw-r--r-- 1 controls controls 35511705 Jul 29 23:59 C-M-1122271200-3600.gwf
-rw-r--r-- 1 controls controls 35809690 Jul 30 00:59 C-M-1122274800-3600.gwf
-rw-r--r-- 1 controls controls 35752082 Jul 30 01:59 C-M-1122278400-3600.gwf
-rw-r--r-- 1 controls controls 35927246 Jul 30 02:59 C-M-1122282000-3600.gwf
-rw-r--r-- 1 controls controls 35775843 Jul 30 03:59 C-M-1122285600-3600.gwf
-rw-r--r-- 1 controls controls 35648583 Jul 30 04:59 C-M-1122289200-3600.gwf
-rw-r--r-- 1 controls controls 35643898 Jul 30 05:59 C-M-1122292800-3600.gwf
-rw-r--r-- 1 controls controls 35704049 Jul 30 06:59 C-M-1122296400-3600.gwf
controls@nodus|minute > ls -l 11223|tail
total 139616
-rw-r--r-- 1 controls controls 35696854 Jul 30 08:02 C-M-1122300000-3600.gwf
-rw-r--r-- 1 controls controls 35675136 Jul 30 08:59 C-M-1122303600-3600.gwf
-rw-r--r-- 1 controls controls 35701754 Jul 30 09:59 C-M-1122307200-3600.gwf
-rw-r--r-- 1 controls controls 35718038 Jul 30 10:59 C-M-1122310800-3600.gwf

LDAS Minute trend:

[koji.arai@ldas-pcdev3 C-M-11]$ pwd
[koji.arai@ldas-pcdev3 C-M-11]$ ls -l |tail
-rw-r--r-- 1 1001 1001 35518238 Jul 29 19:59 C-M-1122256800-3600.gwf
-rw-r--r-- 1 1001 1001 35514930 Jul 29 20:59 C-M-1122260400-3600.gwf
-rw-r--r-- 1 1001 1001 35521183 Jul 29 21:59 C-M-1122264000-3600.gwf
-rw-r--r-- 1 1001 1001 35509281 Jul 29 22:59 C-M-1122267600-3600.gwf
-rw-r--r-- 1 1001 1001 35511705 Jul 29 23:59 C-M-1122271200-3600.gwf
-rw-r--r-- 1 1001 1001 35809690 Jul 30 00:59 C-M-1122274800-3600.gwf
-rw-r--r-- 1 1001 1001 35752082 Jul 30 01:59 C-M-1122278400-3600.gwf
-rw-r--r-- 1 1001 1001 35927246 Jul 30 02:59 C-M-1122282000-3600.gwf
-rw-r--r-- 1 1001 1001 35775843 Jul 30 03:59 C-M-1122285600-3600.gwf
-rw-r--r-- 1 1001 1001 35648583 Jul 30 04:59 C-M-1122289200-3600.gwf

  11466   Thu Jul 30 13:34:52 2015 KojiUpdatePEMY sesimostation is back on

Please check the spectra. If something is wrong, please swap the cables between X and Y in order to see if the cable is still the issue. I believe the cable was nicely made as I carefully checked the connection twice or more during and after the soldering work.

  11475   Sat Aug 1 20:46:29 2015 KojiUpdatePEMX seismo station short cable removed


  11506   Fri Aug 14 12:10:08 2015 KojiUpdatePEMGur interface box is wonky

Let's dismantle the I/F unit from the rack and connect the cable with the lid open.
We need to trace the signal.

  11509   Fri Aug 14 23:49:34 2015 KojiSummaryGeneralB&K Shaker fixed

I fixed a shaker that was claimed to be broken. I had to cut the rubber membrane to open the head.

Once it was opened, the cause of the trouble was obvious. The soldering joint could not put up with the motion of the head.

It is interesting to see that the spring has the damping layer between the metal sheets.

After the repair the DC resistance was measured. It was 1.9Ohm. The side of the shaker chassis said "3.5Ohm, Max 15VA". So it can take more than 4A (wow).

I gave 2A DC from the bench top supply and turn the current on and off. I could confirm the head was moving.

I'll claim the use of this shaker for the seismometer development.

ELOG V3.1.3-