40m QIL Cryo_Lab CTN SUS_Lab TCS_Lab OMC_Lab CRIME_Lab FEA ENG_Labs OptContFac Mariner WBEEShop
  40m Log, Page 314 of 341  Not logged in ELOG logo
ID Date Author Type Category Subjectup
  5103   Wed Aug 3 04:29:48 2011 kiwamuUpdateIOOpeparation for low power MC : HWP+PBS installed

[Suresh / Kiwamu]

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

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

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

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



Power after the EOM = 1.27 W

Power after the HWPs and PBS = 20.2 mW

Power on MCREFL = 20 mW (MC unlocked)

MCREFL_DC = 0.66 V (with MC locked)



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


  1113   Tue Nov 4 01:03:01 2008 ranaSummaryPEMperiodic thump noise in MC1_ACC
There seems to be a periodic thump seen by the MC1 Accelerometers as well as the surrounding optics.

The first 5 hour minute-trend plot shows the periodic thumping as well as the one large saturating event which ruins the
Wiener noise subtraction.

The second plot is a 30 minute second-trend zoom in.
  6299   Tue Feb 21 08:33:16 2012 steveUpdateGreen Lockingperiscope adapter plate

Two extender plates ready for cleaning. The existing optical table tops have 38" OD. Using two of these the OD will be 44"

  1053   Thu Oct 16 13:12:58 2008 peteConfigurationPSLphase between FSS reference outputs
I verified the phase between the FSS reference outputs (used for LO and RF) using matched BNC cables. I measured 0.95 degree (average of 12 scope measurements).
  5384   Sun Sep 11 15:19:39 2011 kiwamuUpdateLSCphase delay in RF signals

A comment :

Since the LSC RFPD have a long cable of more than 6 m, which rotates a 33 MHz signal by more than 360 deg, so the delay has always existed in everywhere.

The circuit you measured is a part of the delay existing in the LSC system, but of course it's not a problem as you said.

In principle a delay changes only the demodulation phase. That's how we treat them.

RA: Actually, the issue is not the delay, but instead the dispersion. Is there a problem if we have too much dispersion from the RF filter?


  10442   Tue Sep 2 22:54:27 2014 KojiSummaryLSCphase tracker UGF


Phase tracker UGF is  Q_AMP * G * 2 PI / 360 where Q_AMP is the amplitude of the Q_ERR output and G is the gain of the phase tracker.

For example: Q_AMP = 270, G = 4000\ => UGF = 1.9kHz

  6832   Mon Jun 18 23:54:31 2012 yutaUpdateGreen Lockingphase tracker for ALS

[Koji, Jenne, Yuta]

  We put phase tracker in FINE loop for ALS. We checked it works, and we scanned Y arm by sweeping the phase of the I-Q rotator.
  From the 8 FSR scan using FINE (30 m delay line), we derived that Y arm finesse is 421 +/- 6.

What we did:
  1. We made new phase rotator because current cdsWfsPhase in CDS_PARTS doesn't have phase input. We want to control phase. New phase rotator currently lives in /opt/rtcds/userapps/trunk/isc/c1/models/PHASEROT.mdl. I checked that this works by sweeping the phase input and monitoring the IQ outputs.

  2. We made a phase tracker (/opt/rtcds/userapps/trunk/isc/c1/models/IQLOCK.mdl) and included in c1gcv model. Unit delay is for making a feed back inside the digital system. Currently it is used only for BEATY_FINE (Simulink diagram below). We edited MEDM screens a little accordingly.

  3. Phase tracking loop has UGF ~ 1.2 kHz, phase margin ~50 deg. They are enough becuase ALS loop has UGF ~ 100 Hz. To control phase tracking loop, use filter module C1:ALS-BEATY_FINE_PHASE (with gain 100). Sometimes, phase tracking loop has large offset because of the integrator and freedom of 360*n in the loop. To relief this, use "CLEAR HISTORY."

  4. Locked Y arm using C1:ALS-BEATY_FINE_PHASE_OUT as an error signal. It worked perfectly and UGF was ~ 90 Hz with gain -8 in C1:ALS-YARM filter module.

  5. Swept phase input to the new phase rotator using excitation point in filter module C1:ALS-BEATY_FINE_OFFSET. Below is the result from this scan. As you can see, we are able to scan for more than the linear range of FINE_I_IN1 signal. We need this extra OFFSET module for scanning because BEATY_FINE_I_ERR stays 0 in the phase tracking loop, and also,  error signal for ALS, output of PHASE module, stays 0 in ALS loop.

  6. We analyzed the data from 8FSR scan by FINE with phase tracker using analyzemodescan.py (below). We got Y arm finesse to be 421 +/- 6 (error in 1 sigma). I think the error for the finesse measurement improved because we could done more linear sweep using phase tracker.

Next things to do:
  - Phase tracker works amazingly. Maybe we don't need COARSE any more.
  - Install it to X arm and do ALS for both arms.
  - From the series of mode scan we did, mode matching to the arm is OK. There must be something wrong in the PRC, not the input beam. Look into PRC mode matching using video capture and measuring beam size.

  8214   Sat Mar 2 20:09:12 2013 yutaUpdateRF Systemphase tracker: DAQ noise limited

[Koji, Yuta]

We found that our phase tracker noise is currently limited by the noise introduced in DAQ.
We confirmed that the frequency noise was improved from 2 Hz/rtHz to 0.4 Hz/rtHz by increasing the gain of the whitening filter.
The whitening filters should definitely be refined.

What we did:
  1. Put constant frequency RF input to the beatbox from Marconi and measured noise spectrum of the beatbox output(BEATX I) after the whitening filter with a spectrum analyzer. Noise floor level was ~0.2 Hz/rtHz at carrier frequency range of 15-100 MHz. Calibration factor of the beatbox output was ~380 mV/MHz.

  2. Measured noise spectrum of C1:ALS-BEATX_FINE_I_OUTPUT(figure below). The noise floor didn't change when there was RF input of 100 MHz from Marconi(blue) and DAQ input was terminated (green). Also, C1:ALS-BEATX_FINE_I_IN1(which is before unwhitening filter) showed a flat spectrum. These show our spectrum is limited by DAQ noise, which is introduced after the whitening filter.

  3. We increased the gain of whitening filter by x20 to show frequency noise performance can be improved by better whitening filter(red). But we can not use this setup as the other quadrature will be saturated by a too much gain at DC. Thus we need to carefully consider the signal level and the gain distribution of the whitening filters.

  - Better whitening filters. The current one consists of zero 1 Hz and pole 10 Hz with DC gain of 5 using SR560.
  - Better beatbox. We can increase the RF input power to the mixer and unify the preamplifier and the whitening filter in the box.

  8094   Sat Feb 16 18:32:01 2013 yutaSummaryRF Systemphase tracker: OLTF

I measured openloop transfer function of the phase tracking loop for the first characterization of phase tracker.

What is phase tracker:

  See elog #6832.
  For ALS, we use delay-line frequency discriminator, but it has trade-off between sensitivity and linear range. We solved this trade-off by tacking the phase of I/Q signals.
  Figure below is the current diagram of the frequency discriminator using phase tracker.

OLTF of phase tracking loop:
  Below. UGF at 1.2 kHz, phase margin 63 deg for both BEATX and BEATY. Phase delay can be clearly explained by 61 usec delay. This delay is 1 step in 16 KHz system.
  Note that UGF depends on the amplitude of the RF input. I think this should be fixed by calculating the amplitude from I/Q signals.
  BEAT(X|Y)_PHASE_GAIN were set to 300, and I put -3dBm 100 MHz RF signal to the beatbox during the measurement.

Other measurements needed:

 - Linear range: By sweeping the RF input frequency and see sensitivity dependence.
 - Bandwidth: By measuring transfer function from the modulation frequency of the RF input to phase tracker output.
 - Maximum sensitivity: Sensitivity dependence on delay-line length (see PSL_Lab #825).
 - Noise: Lock oscillator frequency with phase tracker and measure out-of-loop frequency noise with phase tracker.
 - Sensitivity to amplitude fluctuation: Modulate RF input amplitude and measure the sensitivity.

  8199   Thu Feb 28 05:54:54 2013 yutaUpdateRF Systemphase tracker: calibration

I swept the frequency of RF input to the beatbox to calibrate and check linearity range of phase tracker.
Calibration factors are;
  C1:ALS-BEATX_FINE_PHASE_OUT    52.1643 +/- 0.0003 deg/MHz
  C1:ALS-BEATY_FINE_PHASE_OUT    51.4788 +/- 0.0003 deg/MHz

There was systematic error to the linearity check, but at least, calibration factor changes less than 50 % in the frequency range of 10 MHz to more than 500 MHz.

What I did:
  Used network analyzer(Aligent 4395A) to sweep the frequency RF input to the beatbox and getdata of phase tracker signal. I swept from 10 Hz to 500 MHz with 501 points in 50 sec. This sweep is slow enough considering we could lock the 40m arms (typical speed of a mirror is 1 um/s, so bandwidth of the phase tracker should be more than 1 um/sec / 40 m * 3e14 Hz = 75 MHz/s).
  RF amplitude was set to be -3 dBm and splitted into BEATX and BEATY.

  Plots for BEATX and BEATY are below;

  - Considering delay line length is ~30m, expected calibration factor is;

    2*pi*l/v = 2*pi * 30 m / (2e8 m/s) = 0.94 rad/MHz = 54 deg/MHz

so, this calibration is reasonable.

  - Since frequency sweep of network analyzer is not continuous, phase tracker output is like steps with some ringdown. This makes some systematic error for checking linearity. I'm planning to do slower sweep or continuous sweep. Also, the phase tracker seems like he can exceed 500 MHz.

  8200   Thu Feb 28 06:51:17 2013 yutaUpdateRF Systemphase tracker: noise level

I measured noise level of the phase tracker by inputting constant frequency RF signal from marconi.
Measured frequency noise was ~2 Hz/rtHz @ 100 Hz. It's not so good.

What I did:
  1. Unplugged 11MHz marconi and put RF signal to the beatbox from this. Frequency and amplitude I put are 100 MHz and -3 dBm.
  2. Measured spectra of phase tracker outputs, C1:ALS-BEATX_FINE_PHASE_OUT, C1:ALS-BEATY_FINE_PHASE_OUT.
  3. Calibrated using the factor I measured (elog #8199).
  4. Put marconi back to orignal settings.


  - According to Schilt et al., this noise level is not so good.
  - By changing the delay-line cable length or optimizing whitening filter etc., we can improve this.

  1742   Tue Jul 14 00:57:11 2009 AlbertoUpdateLockingphotodiode alignment check

Since lately the alignment of the input beam to the interferometer has changed, I went checking the alignment of the beam on the photodiodea. They were all fine except for pd9, that is AS DD 199. Here the DC is totally null. The beam seems to go right on the diode but the scope on the PD's DC output shows no power. This is really strange and bad.

  1749   Wed Jul 15 12:14:08 2009 AlbertoUpdateLockingphotodiode alignment check


Since lately the alignment of the input beam to the interferometer has changed, I went checking the alignment of the beam on the photodiodea. They were all fine except for pd9, that is AS DD 199. Here the DC is totally null. The beam seems to go right on the diode but the scope on the PD's DC output shows no power. This is really strange and bad.

After inspecting PD9 with the viewer and the cards, the beam looks like it is aligned to the photodiode althought there is no signal at the DC output of the photodetector. So I checked the spectrum for PD9_i and Q (see attachments) and it seems that those channels are actually seeing the beam. I'm going to check the alignemtn again and see the efefct on the spectra to make sure that the beam is really hitting the PD.


  9186   Wed Oct 2 23:21:54 2013 ranaUpdateComputer Scripts / Programspianosa can't find Jamie PPA

Message on 'pianosa':

Failed to fetch http://ppa.launchpad.net/drgraefy/nds2-client/ubuntu/dists/lucid/main/binary-amd64/Packages.gz  404  Not Found

  9194   Thu Oct 3 08:57:00 2013 jamieUpdateComputer Scripts / Programspianosa can't find Jamie PPA


Message on 'pianosa':

Failed to fetch http://ppa.launchpad.net/drgraefy/nds2-client/ubuntu/dists/lucid/main/binary-amd64/Packages.gz  404  Not Found

Sorry, that was an experiment to see if I could set up a general-use repository for the NDS packages.  I've removed it, and did an update/upgrade.

  6783   Thu Jun 7 10:39:21 2012 JamieUpdateComputerspianosa dual monitor working

I decided to remove what I thought was the problematic extra nVidia video card, since there are already two DVI outputs build-in.  The card turned out to not even be nVidia, so I don't know what was going on there.

I futzed with the BIOS to configure the primary video card, which is some new Intel card.  The lucid (10.04) support for it is lacking, but it was easy enough to pull in new drivers from the appropriate Ubuntu PPA repository:

controls@pianosa:~ 0$ sudo apt-add-repository ppa:f-hackenberger/x220-intel-mesa
controls@pianosa:~ 0$ sudo apt-add-repository ppa:glasen/intel-driver
controls@pianosa:~ 0$ sudo apt-get update
controls@pianosa:~ 0$ sudo apt-get upgrade
Reading package lists... Done
Building dependency tree       
Reading state information... Done
The following packages will be upgraded:
  libdrm-intel1 libdrm-nouveau1 libdrm-radeon1 libdrm2 libgl1-mesa-dri libgl1-mesa-glx libglu1-mesa xserver-xorg-video-intel
8 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.
Need to get 3,212kB of archives.
After this operation, 25.2MB disk space will be freed.
Do you want to continue [Y/n]?
controls@pianosa:~ 0$

After a reboot, both monitors came up fine.


  14003   Fri Jun 22 00:59:43 2018 gautamUpdateCDSpianosa functional, but NO DTT

MEDM, EPICS and dataviewer seem to work, but diaggui still doesn't work (it doesn't work on Rossa either, same problem as reported here, does a fix exist?). So looks like only donatella can run diaggui for now. I had to disable the systemd firewall per the instructions page in order to get EPICS to work. Also, there is no MATLAB installed on this machine yet. sshd has been enabled.

  12262   Wed Jul 6 23:01:03 2016 gautamUpdateGeneralpianosa monitor dead

One of the pianosa monitors has ceased to function frown For now, it has been set up to operate with just the one monitor.

One of Donatella's monitors has a defective display as well. Maybe we should source some replacements. Koji has said we will talk to Larry Wallace about this..

  12267   Thu Jul 7 14:45:26 2016 KojiUpdateGeneralpianosa monitor dead

Johannes, Koji

We obtained two monitors of the same type from Larry.

  14000   Thu Jun 21 22:13:12 2018 gautamUpdateCDSpianosa upgrade

pianosa has been upgraded to SL7. I've made a controls user account, added it to sudoers, did the network config, and mounted /cvs/cds using /etc/fstab. Other capabilities are being slowly added, but it may be a while before this workstation has all the kinks ironed out. For now, I'm going to follow the instructions on this wiki to try and get the usual LSC stuff working.

  14253   Sun Oct 14 16:55:15 2018 not gautamUpdateCDSpianosa upgrade

DASWG is not what we want to use for config; we should use the K. Thorne LLO instructions, like I did for ROSSA.


pianosa has been upgraded to SL7. I've made a controls user account, added it to sudoers, did the network config, and mounted /cvs/cds using /etc/fstab. Other capabilities are being slowly added, but it may be a while before this workstation has all the kinks ironed out. For now, I'm going to follow the instructions on this wiki to try and get the usual LSC stuff working.

  7352   Thu Sep 6 17:11:40 2012 janosch, Manasa, SteveUpdate pick-off and baffle at ETMY

We have installed the pick-off mirror at the ETMY table for the small-angle scattering measurement on ITMY. As we had already done for the X arm pick-off, the pick-off mirror at ETMY was aligned shooting a green laser normally through the viewport on the pick-off and steering it onto ITMY.

A baffle was also installed at a distance of about 30cm from ETMY near the edge of the table.

  5329   Wed Aug 31 14:50:18 2011 kiwamuUpdatePhotospictures of OSEMs

The pictures that we took are now on the Picasa web site. Check it out.

Quote from #5280

Also, we took photos (to be posted on Picasa in a day or two) of all the main IFO magnet-in-OSEM centering, as best we could.  SRM, BS, PRM all caused trouble, due to their tight optical layouts.  We got what we could.

  3987   Fri Nov 26 16:37:29 2010 kiwamuUpdatePhotospictures on PIcasa

 I uploaded some pictures taken in the last and this week. They are on the Picasa web albums.

 in vac work [Nov. 18 2010]

 in vac work [Nov 23 2010]

 CDS work [Nov 24 2010]


  2118   Mon Oct 19 14:48:15 2009 rana, robSummaryElectronicspiezo jena measuring box
Attached is the schematic of the Piezo Jena driver measuring box made in a Pomona box:
                2.2 uF
In ----o-------- | | --------o-------- Out
       |                     |
       _                     |
       _  1uF                R  7.5 kOhms
       |                     |
       |                     |
      GND                   GND
The 1 uF cap is there to simulate the piezo and the 2.2 uF and 7.5k resistor ac couple the signal for the spectrum analyzer. They give a ~10 Hz corner frequency.
  13541   Fri Jan 12 18:08:55 2018 gautamUpdateGeneralpip installed on nodus

After much googling, I figured out how to install pip on SL7:

sudo easy_install pip

Next, I installed git:

sudo yum install git A

Turns out, actually, pip can be installed via yum using

sudo yum install python-pip
  3937   Wed Nov 17 02:53:41 2010 yutaUpdateIOOplaced new PRM to BS table

(Kiwamu, Yuta)

  Yesterday, we aligned the Faraday and the beam reached SM2 at BS table.
  Today, we placed a new PRM tower to BS table.

What we did:

  1. Moved IPPO, IPPOSSM1, IPPOSSM3, IPANGSM1, IPANGSM2 out from the BS chamber.

  2. Moved SRM tower(at PRM's place) to the ITMX chamber.

  3. Placed the new PRM tower at the BS chamber.

  4. Adjusted positions of the OSEMs for PRM and BS so that the sensor output can have roughly half of their maximum.

  5. Checked damping servo for PRM and BS. They were working and helped us when adjusting OSEM positions.

  6. Placed IPPO back and using SM2, made the beam hit PR2 at ITMX table.

  7. Aligned the PRM so that the reflected beam path overlaps the incident beam.
     We checked it by looking at MMT1.
     For the alignment, we used IFO align sliders(C1:SUS-PRM_PIT_COMM, YAW_COMM).
        To use them, we rebooted c1susaux.

  1. The new PRM tower is placed.

  2. OSEM sensor outputs for PRM and BS are;

max current value max current value
ULSEN 1.72 1.006 1.50 0.757
URSEN 1.66 0.918 1.57 0.821
LRSEN 1.92 1.304 1.57 0.821
LLSEN 2.06 1.031 1.38 0.704
SDSEN 9.21 4.366 1.57 0.821

    We changed PRM aligning slider values, and they changed OSEM sensor outputs. We set the slider values to 0 when adjusting OSEM positions.

  4372   Thu Mar 3 00:12:52 2011 kiwamuUpdateGreen Lockingplan
Tomorrow's tasks
  - Auto noise budget (Jamie)
  - Demodulation phase adjustment (Kate)
  - Auto alignment for green (Joe/Kiwamu)
  - ADC connection for the X end green REFL_DC ( )
  - remote local boost for the X end green ( )
  - TDS stuff (Joe)
  - check harmonic distortions on the RF distribution box (Larisa/Koji)
  - connect the X end mechanical shutter to c1auxex (Steve)
  7371   Mon Sep 10 19:04:32 2012 ranaUpdateGeneralplan

 On Friday, Koji and I adjusted the beam pointing into the DRMI using the PZT yaw and found that the beam inside the DRMI (as seen on the AS camera) looked OK (not distorted too much).

So it seems that the issue seen before, namely that the DRMI resonant mode is very strange, is no longer true.

The camera image at the AS port still looks elliptical. So Jenne and Mike have started to make this beam round by adjusting the lenses.

Our plan now is:

1) Fix AS camera optics to get a round beam (single bounce off of ITMY).

2) Flash DRMI to make sure the beam at AS is still round.

3) Using the moveable Watec camera and Sensoray, get images of the spot on all DRMI mirrors with DRMI flashing. Use targets and rulers whenever possible to get quantitative measurements of the beam positions. (i.e. just saying "Oh, its pretty much in the center" is the Mickey Mouse approach to science)

4) Align all pickoff beams in this situation. Make sure there is no in vac clipping. Align IP POS and ANG using this input beam pointing.

5) Pump down.


  4421   Tue Mar 22 00:01:25 2011 kiwamuSummaryGreen Lockingplan for daytime tasks

Some tasks for the daytime tomorrow.

  * Beam profile measurements of the Y end laser  (Suresh / Bryan)

  * Taking care of CDS and the simulated plant (Jamie / Joe)

  * Reconnect the X end mechanical shutter to 1X9 (Kiwamu)

  * LPF for the X end temperature feedback (Larisa)

  4159   Fri Jan 14 20:37:00 2011 kiwamuHowToGreen Lockingplan for this month

 I summarized how we proceed our green locking in this month on the wiki.

Since step1 and 2 shown on the wiki are mostly done apparently, so we will move on to step 3-D and 3-E.

A short term target in the coming couple of days is to phase lock the VCO to the beat note.


  4419   Mon Mar 21 16:49:11 2011 kiwamuSummaryGreen Lockingplan for this week

- Plan for this week

  * Intensity stabilization for the end green laser (Matt / Kiwamu)

  * Hand off the servo from Green to Red (Matt / Kiwamu)

  * Y end green locking (Suresh / Bryan) (rough schedule)

  * Reconnect the X end mechanical shutter to 1X9 (Kiwamu)

  * Connect the end DCPD signal to a DAC (done)

  * Make a LPF in a Pomona box for the temperature (Larisa)

  * Clean up and finalize the X end setup (Kiwamu)

  * Make a item lists for electronics. Order the electronics. (Aidan / Kiwamu)

  13825   Tue May 8 10:24:10 2018 KiraSummaryPEMplan for this week

Here are a few things I will be working on:

  • Design PCB boards for the heater circuit and temperature sensor circuits [by wednesday]
  • Order the front panel I've designed for the seismometer block [today]
  • [next week?] install the new Acromag when it comes
  4426   Wed Mar 23 00:51:47 2011 kiwamuUpdateGreen Lockingplan for tomorrow

  - Plan for tomorrow

    * Video cable session (I need ETMY_TRNAS) (team)

    * Characterization of the Y end laser  (Bryan / Suresh)

    * LPF for the X end laser temperature control (Larisa)

    * Frequency Divider  (Matt)

    * X end mechanical shutter (Kiwamu)

  13501   Wed Jan 3 18:00:46 2018 gautamUpdatePonderSqueezeplan of action

Notes of stuff we discussed @ today's meeting, and afterwards, towards measuring ponderomotive squeezing at the 40m.

  1. Displacement noise requirements
    • Kevin is going to see if we can measure any kind of squeezing on a short timescale by tuning various parameters.
    • Specifically, without requiring crazy ultra low current noise level for the coil driver noise.
  2. Investigate how much actuation range we need for lock acquisition and maintaining lock.
    • Specifically, for DARM.
    • We will measure this by having the arms controlled with ALS in the CARM/DARM basis.
    • Build up a noise budget for this, see how significant the laser noise contribution is.
  3. RC folding mirrors
    • In the present configuration, these are introducing ~2.5% RT loss in the RCs.
    • This affects PRG, and on the output side, measurable squeezing.
    • We want to see if we can relax the requirements on the RC folding mirrors such that we don't have to spend > 20 k$.
    • Specifically, consider spec'ing the folding mirror coatings to only have HR @1064 nm, and take what we get at 532 nm.
    • But still demand tolerances on RoC driven by mode-matching between the RCs and the arm cavities.
  4. ALS with Beat Mouth
    • Use the fiber coupled light from the ends to make the ALS signals.
    • Gautam will update diagram to show the signal chain from end-to-end (i.e. starting at AUX laser, ending at ADC input).
    • Make a noise budget for the same - preliminary analysis suggests a sensing noise floor of ~10 mHz/rtHz.


  • For the ALS-DARM budget the idea is that we can do lock acquisition better, so we don't need to care about the acquisition reqs. i.e. we just need to set the ETM coil driver current range based on the DARM in-lock values.
    • To get the coil driver noise to be low enough to detect squeezing we need to use a ~10-15 kOhm series resistor.
    • We assume that all DAC and coil driver input noises can be sufficiently filtered.
    • We are assuming that we don't change the magnet sizes or the number of coil windings in the OSEMs.
    • The noise in the ITMs doesn't matter because we don't use them for any locking activity, so we can easily set the coil driver series resistors to 15 kOhm.
    • We will do the bias for the ETMs and ITMs using some HV circuit (not the existing ones on the coil driver boards) and doing the summation after the main coil driver series resistor. This HV bias module needs to handle the ~ (2 V / 400 Ohm) = 5 mA which is now used. This would require (5 mA) x (15 kOhm) = 60+ V drivers.
  • IF we can get away with doing the ALS beat note with just red (still using GREEN light from the end laser to lock to the arms from the ends), we will not have any requirements for the 532 nm transmission of any optics in the DRMI area.
    • Get some quotes for the new PR/SR mirrors having tight RoC tolerance, high R for 1064, and no spec for 532.
    • Check that the 1-way fiber noise for 1064 nm is < 100 mHz/rHz in the 50-1000 Hz band. If its more, explore putting better acoustic foam around the fiber run.
    • Improve the mode-matching of the IR beam into the fibers at the ends. We want >80% to reduce the noise do to scattering; we don't really care about the amount of light available in the PSL - this is just to reduce the IR-ALS noise.
  8746   Tue Jun 25 19:18:07 2013 gautamConfigurationendtable upgradeplan of action for PZT installation

  This entry is meant to be a sort of inventory check and a tentative plan-of-action for the installation of the PZT mounted mirrors and associated electronics on the Y-endtable. 

Hardware details:

  •  PZT mounts are cleaned and ready to be put on the end-tables.
  • The PZTs being used are PI S-330.20L Piezo Tip/Tilt Platforms. Each endtable requires two of these. The input channels have male single-lemo connectors. There are 3 channels on each tip/tilt platform, for tilt, yaw and a bias voltage.
  • The driver boards being used are D980323 Rev C. Each board is capable of driving 2 piezo tip/tilt platforms. I am not too sure of this but I think that the SMA female connector on these boards is meant to be connected with the bias voltage from our Kepco high-voltage power supplies. The outputs on these boards are fitted with SMB female connectors, while the piezo tip/tilt platforms have male single-lemo connectors. We will have to source cables with the appropriate connectors to run between the end-table and rack 1Y4 (see below). The input to these boards from the DAC will have to be made with a custom ribbon connector as per the pin out configuration given in the circuit drawing.
  • High-voltage power supply: KEPCO BHK 300-130 MG. This will supply the required 100V DC bias voltage to the piezo tip/tilts via the driver board. Since each board is capable of driving two piezos, we will only need one unit per end-table. The question is where to put these (photo attached). It doesn't look like it can be accommodated in 1Y4 (again photo attached) and the power cable the unit came with is only about 8ft long. If we put these under the end-tables, then we will need an additional long (~10m) cable to run from these to the driver boards at 1Y4 carrying 100 V. 
  •  We will need long (~10m by my rough measurement at the X and Y ends) cables to run from rack 1Y4 to the endtable to drive the piezos. These will have to be high-voltage tolerant (at least to 100V DC) and should have SMB male connectors at one end and female single-lemo connectors at the other. I have emailed 3 firms (CD International Technologies Inc., Stonewall Cables, and Fairview Microwave) detailing our requirements and asking for a quote and estimated time for delivery. We will need 6 of these, plus another cable with an SMA connector on one end and the other end open to connect the 100V DC bias voltage from the high voltage power supply to the driver boards (the power supply comes with a custom jack to which we can solder open leads). We will also possibly need ~3m long lemo-to-?(I need to check what the input connector for the data acquisition channels) cables for the monitoring channels, I am not sure if these are available, I will check with Steve tomorrow.

Other details:

  • I have attached a wiring diagram with the interconnects between various devices at various places and the type of connectors required etc. The error signal will the the transmitted green light from the cavity, and there is already a DQ channel logging this information, so nothing additional wiring is required to this end.
  • Jamie had detailed channel availability in elog 8580. I had a look at rack 1Y4, and there were free DAC channels available, but I am not sure as to which of the ones listed in the elog it corresponds to. In any case, Jamie did mention that there are sufficient channels available at the end-stations for this purposes, but all of these are fast channels. What needs to be decided is if we are going ahead and using the fast channels, or if we need to find slow DAC channels. 
  • I spoke to Koji about gluing the mirrors to the PZTs, and he says we can use superglue, and also to be sure to clean both the mirror and the tip/tilt surfaces before gluing. In any case, all the other hardware issues need to be sorted out first before thinking about gluing the mirrors.

High-Voltage Power Supply



Situation at rack 1Y4



 Wiring diagram


  8800   Wed Jul 3 21:19:04 2013 gautamConfigurationendtable upgradeplan of action for PZT installation

 This is an update on the situation as far as PZT installation is concerned. I measured the required cable (PZT driver board to PZT) lengths for the X and Y ends as well as the PSL table once again, with the help of a 3m long BNC cable, just to make sure we had the lengths right. The quoted cable lengths include a meter tolerance. The PZTs themselves have cable lengths of 1.5m, though I have assumed that this will be used on the tables themselves. The inventory status is as follows.

  1. Stuff ordered:
    • RG316 LEMO 00 (female) to SMB (female) cables, 10 meters - 6pcs (for the Y-end)
    • RG316 LEMO 00 (female) to SMB (female) cables, 11 meters - 6pcs (for the X-end)
    • RG316 LEMO 00 (female) to SMB (female) cables, 15 meters - 8pcs (6 for the PSL, and two spares)
    • RG316 SMA (male) to open cables, 3 meters - 3pcs (1 each for the X end, Y end and PSL table, for connecting the driver boards to the 100V DC power supply)
    • 10 pin IDC connectors for connecting the DAC interface to the PZT driver boards 
  2. Stuff we have:
    • 40 pin IDC connectors which connect to the DAC interface
    • PZT driver boards
    • PZT mounts
    • Twisted ribbon wire, which will be used to make the custom ribbon to connect the 10 pin IDC to the 40 pin IDC connector

I also did a preliminary check on the driver boards, mainly to check for continuity. Some minor modifications have been made to this board from the schematic shown here (using jumper wires soldered on the top-side of the PCB). I will have to do a more comprehensive check to make sure the board as such is functioning as we expect it to. The plan for this is to first check the board without the high-voltage power supply (using an expansion card to hook it up to a eurocrate). Once it has been verified that the board is getting powered, I will connect the high-voltage supply and a test PZT to the board to do both a check of the board as well as a preliminary calibration of the PZTs.

To this end, I need something to track the spot position as I apply varying voltage to the PZT. QPDs are an option, the alternative being some PSDs I found. The problem with the latter is that the interfaces to the PSD (there are 3) all seem to be damaged (according to the labels on two of them). I tried connecting a PSD to the third interface (OT301 Precision Position Sensing Amplifier), and hooked it up to an oscilloscope. I then shone a laser pointer on the psd, and moved it around a little to see if the signals on the oscilloscope made sense. They didn't on this first try, though this may be because the sensing amplifier is not calibrated. I will try this again. If I can get one of the PSDs to work, mount it on a test optical table and calibrate it. The plan is then to use this PSD to track the position of the reflected beam off a mirror mounted on a PZT (temporarily, using double sided tape) that is driven by feeding small-amplitude signals to the driver board via a function generator. 



The LEMO connector on the PZTs have the part number LEMO.FFS.00, while the male SMB connectors on the board have the part number PE4177 (Pasternack)

Plan of Action:

  • The first task will be to verify that the board is working by the methods outlined above.
  • Once the board has been verified, the next task will be to calibrate a PZT using it. I have to first identify a suitable way of tracking the beam position (QPD or PSD?)
  • I have identified a position in the eurocrate at 1Y4 to install the board, and I have made sure that for this slot, the rear of the eurocrate is not hooked up to the cross-connects. I now need to figure out the exact pin configuration at the DAC interface: the bank is marked 'DAC Channels 9-16' (image attached) but there are 40 pins in the connector, so I need to map these pins to DAC channels, so that when making the custom ribbon, I get the pin-to-pin map right.



The wiring scheme has been modified a little, I am uploading an updated one here. In the earlier version, I had mistaken the monitor channels as points from which to log data, while they are really just for debugging. I have also revised the coaxial cable type used (RG316 as opposed to RG174) and the SMB connector (female rather than male).






  4387   Tue Mar 8 15:33:09 2011 kiwamuSummaryGreen Lockingplan on Mar.8th
Today's goal is to measure the contribution from the intensity noise to the beatnote.
Plans for today
  - check the ADC for the DCPD that Jenne installed yesterday
  - adjust RF power on the AOM
  - take spectrum of the differential noise and measure the coupling from the intensity noise
  - update the noise budget

Quote: from #4382
This week's goal is to investigate the source of the differential noise and to lower it.


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

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


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

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

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

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

   + Level the table

   + Adjust the OSEM positions

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

   + Level the table again

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

  3982   Tue Nov 23 23:13:40 2010 kiwamuSummaryCDSplan: we will install C1LSC

 [Joe, Suresh, Kiwamu]

 We will fully install and run the new C1LSC front end machine tomorrow.

And finally it is going to take care of the IOO PZT mirrors as well as LSC codes. 


 (background stroy)

 During the in-vac work today, we tried to energize and adjust the PZT mirrors to their midpoints.

However it turned out that C1ASC, which controls the voltage applying on the PZT mirrors, were not running.

We tried rebooting C1ASC by keying the crate but it didn't come back.

 The error message we got in telnet  was :

   memory init failure !!


 We discussed how to control the PZT mirrors from point of view of both short term and long term operation.

We decided to quit using C1ASC and use new C1LSC instead.

A good thing of this action is that, this work will bring the CDS closer to the final configuration. 


(things to do)

 - move C1LSC to the proper rack (1X4).

 - pull out the stuff associated with C1ASC from the 1Y3 rack.

 - install an IO chasis to the 1Y3 rack.

- string a fiber from C1LSC to the IO chasis.

- timing cable (?)

- configure C1LSC for Gentoo

- run a simple model to check the health

- build a model for controlling the PZT mirrors

  2568   Wed Feb 3 11:13:15 2010 steveConfigurationGeneralplaned power outage for Sat. Feb 20

The electrical shop has to connect the new power transformer at CES. This means we will have no AC power for ~8 hrs on Saturday, February 20

Is this date good for us to power down ALL equipment in the lab?

Rana:  Yes

  4382   Mon Mar 7 18:20:01 2011 kiwamuSummaryGreen Lockingplans
This week's goal is to investigate the source of the differential noise and to lower it.
Plans for tonight
 - realign GREEN_TRANS PD at the PSL table
 - update the noise budget
 - take spectrum of the differential noise
 - investigate a noise coupling to the differential noise especially from the intensity noise
 - update the noise budget again
Plans for this week :
 - Auto alignment scripts for green (Kiwamu)
 - connect the end REFL_DC  to an ADC (Kiwamu)
 - make an active phase rotation circuit for the end PDH (undergrads)
 - bounce-roll notches (Suresh)
 - optimization of the suspensions including the input matrices and the Q-values (Jenne)
 - optimization of MFSS (Koji/Rana/Larisa)
 - rewire the mechanical shutter on the 1X9 binary outputs (Steve)


  6353   Mon Mar 5 06:11:08 2012 kiwamuSummaryLSCplans


  •  DRMI (PRMI) + one arm test before the LVC meeting
  •  Study of the funny sensing matrix and the RAM offset effects before the LVC meeting
  •  Glitch hunting

Action items:

  • MC beam pointing 
    • to make the PZT1 pitch relax
  • OSA setup
    •    a long BNC cable for monitoring the signal in the control room
  • Power budget on the AP table
    • in order to ensure the laser power on each photo diode
  •  POP22/110 sideband monitor
    • installation of an RF amp
    • building a diplexer
    • connect the signals to the demod boards 
  •  Calibration of the demod boards
    • calibrate the conversion loss of the mixers to calibrate all the LSC signals to watts / meter
  •  (1+G) correction for the glitch time series data
  • Simulation study for the RAM offset
    • How much offset do we get due to the RAM ? and how do the offsets screw up the sensing matrix ?
  •  A complete set of the MICH characterization
    •   DC power
    •   Sensing matrix
    •   Noise budget
    •   OSA
    •   Estimation of the RAM offset 
    •  Summarize the results in the wiki
  •  A complete set of the PRMI/DRMI characterization
    •  The same stuff as the MICH characterization
  •  DRMI + one arm test
    •   Monitor the evolution of the sensing matrix during the arm is brought to the resonance


  1624   Mon May 25 21:31:47 2009 carynUpdatePEMplugged in Guralp channels

Guralp Vert1b and Guralp EW1b are plugged back in to PEM ADCU #10 and #12 respectively. Guralp NS1b remains plugged in. So,  PEM-SEIS_MC1_X,Y,Z should now corrsp to seismometer as before.

  1648   Wed Jun 3 12:31:13 2009 carynUpdatePEMplugged in guralp channels
  5063   Fri Jul 29 18:43:02 2011 Manuel, IshwitaUpdatePEMplugging seismometers to ADC

[Manuel, Ishwita, Jenne, Jamie]

We changed the C1PEM model and the names of the C1:PEM channels.

We reinstalled the blue breakout box, since the purple one still didn't work.

So, now the AA board channels are connected as follows...
















C17 = C1:PEM-ACC_MC1_X

C18 = C1:PEM-ACC_MC1_Y

C19 = C1:PEM-ACC_MC1_Z

C20 = C1:PEM-ACC_MC2_X

C21 = C1:PEM-ACC_MC2_Y

C22 = C1:PEM-ACC_MC2_Z

Although the channels for all 3 STS-2 seismometers are made but only one is installed. So only Channels C1 to C9 are now in operation...

We checked the data from the plugged channels with the Dataviewer. We could see the peak whenever someone jumped in the lab. Even Kiwamu jumped and saw his signal.

  4345   Wed Feb 23 16:34:42 2011 valeraConfiguration pmc lens staged

I put the PMC last mode matching lens (one between the steering mirrors) on a translation stage to facilitate the PMC mode matching.

Currently 4% of incident power is reflected by the PMC. But the reflected beam does not look "very professional" on the camera to Rana - meaning there is too much TEM20 (bulls eye) mode in the reflected beam.

I locked the  PMC  on bulls eye mode and measured  the ratio of the TEM20/TEM00 in transmission to be 1.3%. Thus the PMC mode matching is ~99% and the incident beam HOM content is ~3%.

While working on the PMC I found that the source of PMC "blinking" is not the frequency control signal from MC to the laser (the MC servo was turned off) but possibly some oscillation which could be affected even by a small change of the pump current 2.10 A to 2.08 A. I showed this behaviour to Kiwamu and we decided to leave the the current at 2.08 A for now where things look stable and investigate later.

  9961   Fri May 16 09:46:05 2014 SteveUpdatePSLpointing monitoring


 Tonight I noticed that the drop in PMC transmission was ~1V, more than the usual of ~0.5V from the daily drift.

While re-aligning on the table, I noticed that the misalignment was not from either of the steering mirrors; i.e. I has to walk them both to get the alignment back. This implies that the misalignment is generated far upstream. Maybe the the laser itself is moving. We need some updates from Steve's laser misalignment tracker.

I'd like to replace the paper target with IOO -QPD_POS so we can log it.

  11820   Sat Nov 28 11:46:40 2015 yutaroUpdateLSCpossible error source of loss map measurement

I found that TRY level degraded and the beam shape seen with CCD camera at AS port was splitted when the beam spot on ETMY was not close to the center. This was because dither started not working well. I suspect so because in such a case TRY level went up when I did iteration with TT1 and TT2 after freezing dither. Splitted beam shape indicates that incident light did not match well with the cavity mode.

TRY level for each point was this:

[[ 0.6573      0.8301      0.8983      0.8684      0.6773    ]
 [ 0.7555      0.8904      0.9394      0.8521      0.6779    ]
 [ 0.6844      0.8438      0.9318      0.8834      0.6593    ]
 [ 0.7429      0.8688      0.9254      0.8427      0.6474    ]
 [ 0.7034      0.8447      0.8834      0.8147      0.6966    ]]

 In the worst case, TRY level was 70 % of the maximum level. Assuming that this degrade was totally due to the mode mismatch, this corresponds to ~50 urad difference between the angle of incident light and resonant lighe in the arm (see elog 11819).

  8078   Wed Feb 13 19:09:32 2013 yutaSummaryGeneralpossible explanations to oval REFL beam

[Jenne, Manasa, Jamie, Yuta]

The shape of the REFL beam reflected from PRM is oval after the Faraday.
We tried to fix it by MC spot position centering and by tweaking input TT1/TT2/PRM. But REFL still looks bad (below).


What has changed since:
  REFL looks OK in mid-Dec 2012. Possibly related things changed are;

  1. New active input TTs with new mirrors installed
  2. Leveling of IMC stack changed a little (although leveling was done after installing TTs)

Possible explanations to oval REFL:
  A. Angled input beam:
    Input beam is angled compared with the Faraday apertures. So, beam coming back from PRM is angled, and clipped by the Faraday aperture at the rejection port.

  B. Mode mis-match to PRM:
    New input TTs have different curvatures compared with before. Input mode matching to PRM is not good and beam reflected from PRM is expanding. So, there's clipping at the Faraday.

  C. Not clipping, but astigmatism:
    New input TTs are not flat. Incident angle to TT2 is ~ 45 deg. So, it is natural to have different tangential/sagittal waist sizes at REFL.

How to check:
  A. Angled input beam:
    Look beam position at the Faraday apertures. If it doesn't look centered, the incident beam may be angled.
   (But MC centering didn't help much......)

  B. Mode mis-match to PRM:
    Calculate how much the beam size will be at the Faraday when the beam is reflected back from PRM. Put some real numbers to curvatures of input TTs for calculation.

  C. Not clipping, but astigmatism:
    Same calculation as B. Let's see if REFL is with in our expectation or not by calculating the ratio of tangential/sagittal waist sizes at REFL.

ELOG V3.1.3-