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  Coating Ring-down Measurement Lab elog, Page 12 of 18  Not logged in ELOG logo
ID Date Author Type Category Subject
  331   Fri Mar 10 16:44:13 2017 GabrieleOpticsDaily ProgressUpdated in vacuum periscope of CR0

This afternoon I removed the old periscope from CR0 and installed a new one with finely adjustable mount, like those in the new chamber. I realigned the optical lever to the horizontal refererence.

  330   Tue Mar 7 11:09:33 2017 GabrieleGeneralMeasurementsNew MIT sample #3

2017-03-07

  • 11:08am, in chamber CR0
  • 11:09am, roughing pump on
  • 11:23am turbo pump on
  • 3:37pm, pumps stopped, the turbo is saturating CR1

2017-03-08

  • 8:00am pumps restarted
  • Excitations
    • Quiet time before excitation: 1173048953
      Excitation broadband: 1173048986
      Quiet time after excitation: 1173049018

    • Quiet time before excitation: 1173050248
      Excitation broadband: 1173050280
      Quiet time after excitation: 1173050312

    • Quiet time before excitation: 1173051542
      Excitation broadband: 1173051574
      Quiet time after excitation: 1173051606

    • Quiet time before excitation: 1173052836
      Excitation broadband: 1173052868
      Quiet time after excitation: 1173052900

    • Quiet time before excitation: 1173054130
      Excitation broadband: 1173054163
      Quiet time after excitation: 1173054195

    • Quiet time before excitation: 1173055425
      Excitation broadband: 1173055457
      Quiet time after excitation: 1173055489

2017-03-09

  • 10:10am, pumps off
  329   Tue Mar 7 11:01:58 2017 GabrieleGeneralMeasurementsS1600469 S1600471 S1600481 S1600483

2017-03-07

  • 10:57am, in chamber
    • S1600469 in CR1
    • S1600471 in CR2
    • S1600481 in CR3
    • S1600483 in CR4
  • 11:02am, roughing pump on
  • 11:11am, turbo pump on
  • Excitations
    • Quiet time before excitation: 1172968827
      Excitation broadband: 1172968862
      Quiet time after excitation: 1172968927

    • Quiet time before excitation: 1172970757
      Excitation broadband: 1172970792
      Quiet time after excitation: 1172970857

    • Quiet time before excitation: 1172972687
      Excitation broadband: 1172972723
      Quiet time after excitation: 1172972788

    • Quiet time before excitation: 1172974618
      Excitation broadband: 1172974653
      Quiet time after excitation: 1172974718

    • Quiet time before excitation: 1172976548
      Excitation broadband: 1172976583
      Quiet time after excitation: 1172976648

    • Quiet time before excitation: 1172978478
      Excitation broadband: 1172978513
      Quiet time after excitation: 1172978578

    • Quiet time before excitation: 1172980408
      Excitation broadband: 1172980443
      Quiet time after excitation: 1172980508

    • Quiet time before excitation: 1172982338
      Excitation broadband: 1172982373
      Quiet time after excitation: 1172982438

2017-03-08

  • 8:00am pumps off, gate valve closed
  328   Fri Mar 3 13:01:59 2017 GabrieleGeneralMeasurementsNew MIT sample #2

2017-03-03

  • 1:00pm, in chamber, realigned optical lever to get as close as possible to the edge of the disk
  • 1:02pm, roughing pump on
  • 1:14pm, turbo pump on
  • Excite
    • Quiet time before excitation: 1172633160
      Excitation broadband: 1172633192
      Quiet time after excitation: 1172633224

    • Quiet time before excitation: 1172634454
      Excitation broadband: 1172634486
      Quiet time after excitation: 1172634518

    • Quiet time before excitation: 1172635748
      Excitation broadband: 1172635781
      Quiet time after excitation: 1172635813

    • Quiet time before excitation: 1172637043
      Excitation broadband: 1172637075
      Quiet time after excitation: 1172637107

    • Quiet time before excitation: 1172638337
      Excitation broadband: 1172638369
      Quiet time after excitation: 1172638401

    • Quiet time before excitation: 1172639631
      Excitation broadband: 1172639663
      Quiet time after excitation: 1172639695

2017-03-06

  • 10:18am, pumps off

 

  327   Fri Mar 3 13:00:50 2017 GabrieleGeneralMeasurementsS1600453 S1600490

2017-03-03

  • 12:45pm, in chamber
    • S1600453 in CR3
    • S1600490 in CR4
  • 12:45pm roughing pump on
  • 12:56pm, turbo pump on
  • Excitation
    • Quiet time before excitation: 1172620986
      Excitation broadband: 1172621021
      Quiet time after excitation: 1172621086

    • Quiet time before excitation: 1172622916
      Excitation broadband: 1172622951
      Quiet time after excitation: 1172623016

    • Quiet time before excitation: 1172624846
      Excitation broadband: 1172624881
      Quiet time after excitation: 1172624946

    • Quiet time before excitation: 1172626776
      Excitation broadband: 1172626811
      Quiet time after excitation: 1172626876

    • Quiet time before excitation: 1172628706
      Excitation broadband: 1172628742
      Quiet time after excitation: 1172628807

    • Quiet time before excitation: 1172630638
      Excitation broadband: 1172630673
      Quiet time after excitation: 1172630738

    • Quiet time before excitation: 1172632568
      Excitation broadband: 1172632603
      Quiet time after excitation: 1172632668

    • Quiet time before excitation: 1172634498
      Excitation broadband: 1172634534
      Quiet time after excitation: 1172634599

2017-03-06

  • 10:19am, gate valve closed, pumps off
  326   Thu Mar 2 11:27:47 2017 GabrieleGeneralNoise huntingTurbo pump of CR0 pollutes CR1

The turbo pump of the CR0 chamber runs at 833 Hz. It causes vibrations that pollute the measurements in the CR1-4 chamber. In particular CR1 is extremely sensitive and the line is highly up-converted. It's not clean why CR1 is more sensitive than CR2-3-4.

  325   Thu Mar 2 09:45:58 2017 GabrieleGeneralMeasurementsS1600456 S1600458 S1600461 S1600491

2017-03-02

  • 9:31am, in chamber, removed ND from path 2-4
    • S1600456 in CR1
    • S1600458 in CR2
    • S1600461 in CR3
    • S1600491 in CR4
  • 9:45am roughing pump on
  • 9:55am turbo pump on
  • Excitations
    • Quiet time before excitation: 1172530103
      Excitation broadband: 1172530139
      Quiet time after excitation: 1172530204

    • Quiet time before excitation: 1172532034
      Excitation broadband: 1172532069
      Quiet time after excitation: 1172532134

    • Quiet time before excitation: 1172533964
      Excitation broadband: 1172533999
      Quiet time after excitation: 1172534064

    • Quiet time before excitation: 1172535894
      Excitation broadband: 1172535929
      Quiet time after excitation: 1172535994

    • Quiet time before excitation: 1172537824
      Excitation broadband: 1172537859
      Quiet time after excitation: 1172537924

    • Quiet time before excitation: 1172539754
      Excitation broadband: 1172539789
      Quiet time after excitation: 1172539854

    • Quiet time before excitation: 1172541684
      Excitation broadband: 1172541719
      Quiet time after excitation: 1172541784

    • Quiet time before excitation: 1172543614
      Excitation broadband: 1172543649
      Quiet time after excitation: 1172543714

2017-03-03

  • 9:30am, gate valve closed, pumps stopped, venting
  324   Wed Mar 1 10:10:47 2017 GabrieleGeneralMeasurementsS1600469 S1600471 S1600481 S1600483

2017-03-01

  • 10:10am, in chamber, added neutral densities
    • S1600469 in CR1
    • S1600471 in CR2
    • S1600481 in CR3
    • S1600483 in CR4
  • 10:12am, roughing pump on, clamps on
  • 10:22am, turbo pump on
  • Excitations:
    • Quiet time before excitation: 1172438462
      Excitation broadband: 1172438497
      Quiet time after excitation: 1172438562

    • Quiet time before excitation: 1172440392
      Excitation broadband: 1172440427
      Quiet time after excitation: 1172440492

    • Quiet time before excitation: 1172442322
      Excitation broadband: 1172442357
      Quiet time after excitation: 1172442422

    • Quiet time before excitation: 1172444252
      Excitation broadband: 1172444287
      Quiet time after excitation: 1172444352

    • Quiet time before excitation: 1172446182
      Excitation broadband: 1172446217
      Quiet time after excitation: 1172446282

    • Quiet time before excitation: 1172448112
      Excitation broadband: 1172448148
      Quiet time after excitation: 1172448213

    • Quiet time before excitation: 1172450044
      Excitation broadband: 1172450079
      Quiet time after excitation: 1172450144

    • Quiet time before excitation: 1172451974
      Excitation broadband: 1172452009
      Quiet time after excitation: 1172452074

2017-03-02

  • 9:00am, vented, samples removed
  323   Tue Feb 28 14:20:50 2017 GabrieleGeneralMeasurementsNew MIT sample #1

2017-02-28

  • 2:19pm, installed in CR0, balanced, with 1/2" inserts facing down
    • It looks dusty and there is a fingerprint on the edge. I didn't clean it
  • 2:21pm, roughing pump on
  • 2:35pm, turbo pump on
  • Excitations:
    • Quiet time before excitation: 1172377933
      Excitation broadband: 1172377965
      Quiet time after excitation: 1172378027

    • Quiet time before excitation: 1172381657
      Excitation broadband: 1172381689
      Quiet time after excitation: 1172381751

    • Quiet time before excitation: 1172385381
      Excitation broadband: 1172385414
      Quiet time after excitation: 1172385476

    • Quiet time before excitation: 1172389106
      Excitation broadband: 1172389138
      Quiet time after excitation: 1172389200

    • Quiet time before excitation: 1172392830
      Excitation broadband: 1172392863
      Quiet time after excitation: 1172392925

    • Quiet time before excitation: 1172396555
      Excitation broadband: 1172396587
      Quiet time after excitation: 1172396649

 

2017-03-01

  • 9:36am, pumps stopped

2017-03-02

  • 9:00am. The laser beam was probably hitting one of the glued inserts. Checked that te disk is not touching, moved the ESD a bit lower
  • 9:04am, roughing pump on
  • 9:17am, turbo pump on
  • 1:50pm, pumps off
  322   Tue Feb 28 11:22:35 2017 GabrieleGeneralMeasurementsS1600463 S1600466 S1600475 S1600476

2017-02-28

  • 11:20am, in chamber
    • S1600463 in CR1
    • S1600466 in CR2
    • S1600475 in CR3
    • S1600476 in CR4
  • 2:10pm, roughing pump on
  • 2:20pm, turbo pump on
  • Excitations
    • Quiet time before excitation: 1172366632
      Excitation broadband: 1172366667
      Quiet time after excitation: 1172366732

    • Quiet time before excitation: 1172373962
      Excitation broadband: 1172373997
      Quiet time after excitation: 1172374062

    • Quiet time before excitation: 1172381292
      Excitation broadband: 1172381327
      Quiet time after excitation: 1172381392

    • Quiet time before excitation: 1172388622
      Excitation broadband: 1172388657
      Quiet time after excitation: 1172388722

2017-03-01

  • 9:31am, venting
  321   Mon Feb 27 13:13:05 2017 GabrieleGeneralMeasurementsS1600490

2017-02-27

  • 12:59pm, installed in chamber CR0, balanced
  • 1:00pm, roughing pump on
  • 1:13pm, turbo pump on
  • 3:04pm, stopped pumps
  320   Mon Feb 27 08:42:05 2017 GabrieleGeneralMeasurementsS1600453 S1600490

2017-02-27

  • 8:40am, in chamber, balanced
    • S1600453 in CR1
    • S1600491 in CR2 (i meant to install 490, but got confused)
  • 10:23am, roughing pump on, clamps on
  • 10:32am, turbo pump on
  • 3:01pm, something is wrong with CR1 (the 666 Hz line due to the turbo pump is very large and saturates the QPD signals). Venting
  • 4:11pm in chamber
    • S1600453 in CR1
    • S1600490 in CR2
  • 4:12pm roughing pump on, clamps on
  • 4:20pm turbo pump on
  • Excitations
    • Quiet time before excitation: 1172290836
      Excitation broadband: 1172290871
      Quiet time after excitation: 1172290936

    • Quiet time before excitation: 1172292766
      Excitation broadband: 1172292801
      Quiet time after excitation: 1172292866

    • Quiet time before excitation: 1172294696
      Excitation broadband: 1172294731
      Quiet time after excitation: 1172294796

    • Quiet time before excitation: 1172296626
      Excitation broadband: 1172296661
      Quiet time after excitation: 1172296726

    • Quiet time before excitation: 1172298556
      Excitation broadband: 1172298591
      Quiet time after excitation: 1172298656

    • Quiet time before excitation: 1172300486
      Excitation broadband: 1172300522
      Quiet time after excitation: 1172300587

    • Quiet time before excitation: 1172302417
      Excitation broadband: 1172302452
      Quiet time after excitation: 1172302518

    • Quiet time before excitation: 1172304348
      Excitation broadband: 1172304383
      Quiet time after excitation: 1172304448

2017-02-28

  • 11:08am, vented
  319   Fri Feb 24 14:44:22 2017 GabrieleGeneralGeneralDisk model

It's possible to build an analytical model of the resonant frequencies of a simple thin disk. For example, see J. Sound and Vibrations 188, 685 (1995), section 2

The solutions are given in term of Bessel functions:

W_{mn}(r, \theta)=\left[ J_m(\lambda_{mn} r/a) + C_{mn} I_m(\lambda_{mn} r/a)\right] \cos m \theta

where J is a Bessel function of the first kind, and I a modified Bessel function of the first kind, a is the disk radius.

The coefficient Cmn and the eigenvalue can be found as solution of the following two equations

Then the eigenfrequencies are given by

f_{mn} = \frac{\lambda_{mn}^2}{2\pi a^2}\sqrt{\frac{D}{\rho h}}

where rho is the material density, h the disk thickness and D the flexural rigidity

D =\frac{E h^3}{12(1-\nu^2)}

where E is the material Young's modulus and nu the Poisson's ratio.

From all those results we can conclude that the frequency scaling with respect to disk radius and thickness are very simple:

  • the frequencies scale linearly with the thickness
  • the frequencies scale inversely proportionally to the square of the radius

Also, the frequencies scales as sqrt(E/rho)

f_{nm} \propto \sqrt{\frac{E}{\rho}} \frac{h}{a^2}

The dependency on the Poisson's ratio is more complex since nu is involved in the eigenfrequency equation shown above.

Unfortunately the thin disk model does not exactly match the COMSOL results: deviations of few tens of Hz are present, probaly due to the thin disk approximation. The COMSOL model is more accurate to match the experimental frequencies.

However, I checked that the eigenfrequencies predicted by COMSOL also scales as predicted with thickness and radius.

Using the measurements on the six samplex we got from Mark Optics, after annealing, I was able to tune the COMSOL model to fit all measured frequencies within 6 Hz. I chose to change the disk thickness (since diameter and Young'r modulus are degenerate) and the Poisson's ratio. 

Here is an example of the difference between the measured and modeled frequencies:

The table below summarizes the best fit for each of the disks

SN Thickness [mm] Poisson's ratio
S1600519 1.0194 0.1669
S1600520 1.0186 0.1663
S1600521 1.0217 0.1669
S1600522 1.0223 0.1635
S1600523 1.0227 0.1655
S1600524 1.0209 0.1654

Since the material is the same, I would expect the Poisson's ratio to be constant. So for future modeling I'm using the average of the values above: 0.166

  318   Fri Feb 24 13:21:03 2017 GabrieleGeneralMeasurementsQ of substrates with polished edges

Below the measured Q values of the six Suprasil 313 substrates, with polished edges, after annealing at 900 degrees C for 9 hours.

They are all consistently at a level of 100e6 at 1 KHz and showing a similar frequency dependency going down to a about 30e6 at 20-30 kHz. The only exception is S1600522 which has clearly lower Q values at all frequencies.

Below a comparison of the substrate loss angles compared wiht Steve Penn's model:

  317   Fri Feb 24 11:05:58 2017 GabrieleGeneralMeasurementsS1600456 S1600458 S1600461 S1600491

2017-02-24

  • 10:50am, in chamber, balanced, added neutral density to laser on the 1/3 path
    • S1600456 in CR1
    • S1600458 in CR2
    • S1600461 in CR3
    • S1600491 in CR4
  • 10:56am, roughing pump on, clamps on
  • 11:05am, turbo pump on
  • Excitations
    • Quiet time before excitation: 1172009197
      Excitation broadband: 1172009232
      Quiet time after excitation: 1172009297

    • Quiet time before excitation: 1172011127
      Excitation broadband: 1172011162
      Quiet time after excitation: 1172011227

    • Quiet time before excitation: 1172013057
      Excitation broadband: 1172013092
      Quiet time after excitation: 1172013157

    • Quiet time before excitation: 1172014987
      Excitation broadband: 1172015022
      Quiet time after excitation: 1172015087

    • Quiet time before excitation: 1172016917
      Excitation broadband: 1172016952
      Quiet time after excitation: 1172017017

    • Quiet time before excitation: 1172018847
      Excitation broadband: 1172018882
      Quiet time after excitation: 1172018947

    • Quiet time before excitation: 1172020777
      Excitation broadband: 1172020812
      Quiet time after excitation: 1172020877

    • Quiet time before excitation: 1172022707
      Excitation broadband: 1172022742
      Quiet time after excitation: 1172022807

2017-02-27

  • 8:32am venting
  316   Thu Feb 23 10:54:41 2017 GabrieleGeneralMeasurementsS1600523 S1600524

2017-02-23

  • 10:35am in chamber, balanced
    • S1600523 in bay 1
    • S1600524 in bay 2
  • 10:45am, roughing pump on, clamps on
  • 10:55am, turbo pump on
  • Excitations:
    • Quiet time before excitation: 1171925035
      Excitation broadband: 1171925070
      Quiet time after excitation: 1171925085

    • Quiet time before excitation: 1171935915
      Excitation broadband: 1171935950
      Quiet time after excitation: 1171935965

    • Quiet time before excitation: 1171946795
      Excitation broadband: 1171946830
      Quiet time after excitation: 1171946845

    • Quiet time before excitation: 1171957675
      Excitation broadband: 1171957710
      Quiet time after excitation: 1171957725

2017-02-24

  • 8:40am, gate valve close, pumps off, venting
  315   Wed Feb 22 15:11:59 2017 GabrieleGeneralMeasurementsS1600519 S1600520 S1600521 S1600522

2017-02-22

  • 2:59pm, in chamber, balanced, removed all neutral densities
  • 3:02pm, roughing pump on, clamps on
  • 3:11pm, turbo pump on
  • Excitations
    • Quiet time before excitation: 1171847838
      Excitation broadband: 1171847873
      Quiet time after excitation: 1171847888

    • Quiet time before excitation: 1171858718
      Excitation broadband: 1171858754
      Quiet time after excitation: 1171858769

    • Quiet time before excitation: 1171869599
      Excitation broadband: 1171869634
      Quiet time after excitation: 1171869649

    • Quiet time before excitation: 1171880479
      Excitation broadband: 1171880514
      Quiet time after excitation: 1171880530

 

2017-02-23

  • 10:22am, gate valve closed, pumps off, venting

 

  314   Wed Feb 22 13:56:15 2017 GabrieleElectronicsConfigurationSoftware improvements
  1. created a single interface to move the picomotors in front of QPD1 ... QPD4
    • the command qpdcenter will open an interactive python shell to control the picomotors
  2. two scripts for automatic excitations are saved in /opt/rtcds/userapps/CyMAC/src/auto_excite*.py
    • they must run on the cymac. But they can be started from the control station using the commands autoexcite0 and autoexcite14
    • before starting the commands, set the parameters in the file. The two commands edit_autoexcite0 and edit_autoexcite14 will open the correct files
    • a log file of the excitation times will be saved
    • the scripts will check if there is an excitation going
  3. the two commands noise0 and noise14 can be used to start awggui to inject the correct noise
  4. updated the autocentering scripts, so that only one instance can run at a time.
    • launch them with the commands autocenter0 and autocenter14
  313   Sun Feb 19 11:46:26 2017 GabrieleGeneralMeasurementsS1600458 S1600474 S1600491

2017-02-19

  • 11:28am an chamber:
    • S1600458 in CR1
    • S1600474 in CR2
    • S1600491 in CR3
    • empty CR4
  • 11:46am roughing pump on, clamps on
  • 11:57am turbo pump on
  • Excitations:
    • Quiet time before excitation: 1171579753
      Excitation (broad band) at 1171579788 (60 s)
      Quiet time after excitation: 1171579854

    • Quiet time before excitation: 1171581684
      Excitation (broad band) at 1171581719 (60 s)
      Quiet time after excitation: 1171581784

    • Quiet time before excitation: 1171583614
      Excitation (broad band) at 1171583649 (60 s)
      Quiet time after excitation: 1171583714

    • Quiet time before excitation: 1171585545
      Excitation (broad band) at 1171585580 (60 s)
      Quiet time after excitation: 1171585645

    • Quiet time before excitation: 1171587475
      Excitation (broad band) at 1171587510 (60 s)
      Quiet time after excitation: 1171587575

    • Quiet time before excitation: 1171589405
      Excitation (broad band) at 1171589440 (60 s)
      Quiet time after excitation: 1171589505

    • Quiet time before excitation: 1171591335
      Excitation (broad band) at 1171591370 (60 s)
      Quiet time after excitation: 1171591435

    • Quiet time before excitation: 1171593265
      Excitation (broad band) at 1171593300 (60 s)
      Quiet time after excitation: 1171593365

2017-02-21

  • 10:30am, gate valve closed, pumps stopped, venting
  312   Sat Feb 18 15:04:00 2017 GabrieleGeneralMeasurementsS1600481 S1600483 S1600469 S1600471

2017-02-18

  • 9:54am in chamber, balanced
    • S1600469 in CR1
    • S1600471 in CR2
    • S1600481 in CR3
    • S1600483 in CR4
  • 10:00am, roughing pump on, clamps on
  • 10:13am, turbo pump on
  • Excitations
    • Quiet time before excitation: 1171492847
      Excitation (broad band) at 1171492882 (60 s)
      Quiet time after excitation: 1171492947

    • Quiet time before excitation: 1171494777
      Excitation (broad band) at 1171494813 (60 s)
      Quiet time after excitation: 1171494878

    • Quiet time before excitation: 1171496708
      Excitation (broad band) at 1171496743 (60 s)
      Quiet time after excitation: 1171496808

    • Quiet time before excitation: 1171498638
      Excitation (broad band) at 1171498673 (60 s)
      Quiet time after excitation: 1171498738

    • Quiet time before excitation: 1171500568
      Excitation (broad band) at 1171500603 (60 s)
      Quiet time after excitation: 1171500668

    • Quiet time before excitation: 1171502498
      Excitation (broad band) at 1171502533 (60 s)
      Quiet time after excitation: 1171502598

    • Quiet time before excitation: 1171504428
      Excitation (broad band) at 1171504463 (60 s)
      Quiet time after excitation: 1171504528

    • Quiet time before excitation: 1171506358
      Excitation (broad band) at 1171506393 (60 s)
      Quiet time after excitation: 1171506458

  • More excitations:

    • Quiet time before excitation: 1171509354
      Excitation (broad band) at 1171509389 (60 s)
      Quiet time after excitation: 1171509454

    • Quiet time before excitation: 1171511284
      Excitation (broad band) at 1171511319 (60 s)
      Quiet time after excitation: 1171511384

    • Quiet time before excitation: 1171513214
      Excitation (broad band) at 1171513249 (60 s)
      Quiet time after excitation: 1171513314

    • Quiet time before excitation: 1171515144
      Excitation (broad band) at 1171515179 (60 s)
      Quiet time after excitation: 1171515244

    • Quiet time before excitation: 1171517074
      Excitation (broad band) at 1171517109 (60 s)
      Quiet time after excitation: 1171517174

    • Quiet time before excitation: 1171519004
      Excitation (broad band) at 1171519039 (60 s)
      Quiet time after excitation: 1171519104

    • Quiet time before excitation: 1171520934
      Excitation (broad band) at 1171520969 (60 s)
      Quiet time after excitation: 1171521034

    • Quiet time before excitation: 1171522864
      Excitation (broad band) at 1171522899 (60 s)
      Quiet time after excitation: 1171522964

2017-02-19

  • 11:11am, gate valve closed, pumps stopped, venting
     

 

  311   Fri Feb 17 13:44:47 2017 GabrieleOpticsDaily ProgressSwapped picomotor and re-alignment

Since I had recurrent problems with the picomotors used for QPD3, I swapped them with another Newport motorized mirror that was previously used in the Crackle1 experiment. This is the same model used for the other three QPD centering. Everything looks to be working fine now.

I also realigned all optical levers and swapped out an iris with a smaller one, to avoid beam clipping. All beam paths look clear now.

  310   Thu Feb 16 10:19:33 2017 GabrieleGeneralMeasurementsS1600453 S1600456 S1600461 S1600490

2017-02-16

  • 10:17am in chamber
    • S1600453 in CR1
    • S1600456 in CR2
    • S1600461 in CR3
    • S1600490 in CR4
  • Notes:
    • added ND03 on path to CR1 and CR3, since QPD were saturating
    • there is something wrong with CR1, the spectrum is very noisy. I checked that there is no clipping of the beam. I also tried to move the spot on the disk, without change. Maybe the disk is touching?
  • 10:18am, roughing pump on, clamps on
  • 10:21am, turbo pump on
  • Excitations: (NOTE: bay 1 noise spectrum is very bad. The autocetering of bay 3 failed, so the QPD was not centered for most of the time)
    • Quiet time before excitation: 1171326574
      Excitation (broad band) at 1171326609 (60 s)
      Quiet time after excitation: 1171326674

    • Quiet time before excitation: 1171328504
      Excitation (broad band) at 1171328539 (60 s)
      Quiet time after excitation: 1171328604

    • Quiet time before excitation: 1171330434
      Excitation (broad band) at 1171330469 (60 s)
      Quiet time after excitation: 1171330534

    • Quiet time before excitation: 1171332364
      Excitation (broad band) at 1171332399 (60 s)
      Quiet time after excitation: 1171332465

    • Quiet time before excitation: 1171334295
      Excitation (broad band) at 1171334330 (60 s)
      Quiet time after excitation: 1171334395

    • Quiet time before excitation: 1171336225
      Excitation (broad band) at 1171336260 (60 s)
      Quiet time after excitation: 1171336325

    • Quiet time before excitation: 1171338155
      Excitation (broad band) at 1171338191 (60 s)
      Quiet time after excitation: 1171338256

    • Quiet time before excitation: 1171340086
      Excitation (broad band) at 1171340121 (60 s)
      Quiet time after excitation: 1171340186

2017-02-17

  • 8:43am gate valve closed, pump stopped, venting slowly
  • the measurements carried out last night didn't look very good, mostly because it seems that the picomotor of QPD3 got crazy and was shaking too much the bench
  • 12:19pm, balanced again, roughing pump on. Added ND03 and ND04 to lasers to avoid QPD saturations
  • 12:49pm, turbo pump on
  • Excitations:
    • Quiet time before excitation: 1171425425
      Excitation (broad band) at 1171425460 (60 s)
      Quiet time after excitation: 1171425525

    • Quiet time before excitation: 1171427355
      Excitation (broad band) at 1171427390 (60 s)
      Quiet time after excitation: 1171427455

    • Quiet time before excitation: 1171429285
      Excitation (broad band) at 1171429320 (60 s)
      Quiet time after excitation: 1171429385

    • Quiet time before excitation: 1171431215
      Excitation (broad band) at 1171431250 (60 s)
      Quiet time after excitation: 1171431315

    • Quiet time before excitation: 1171433145
      Excitation (broad band) at 1171433180 (60 s)
      Quiet time after excitation: 1171433245

    • Quiet time before excitation: 1171435075
      Excitation (broad band) at 1171435110 (60 s)
      Quiet time after excitation: 1171435176

    • Quiet time before excitation: 1171437006
      Excitation (broad band) at 1171437041 (60 s)
      Quiet time after excitation: 1171437106

    • Quiet time before excitation: 1171438936
      Excitation (broad band) at 1171438971 (60 s)
      Quiet time after excitation: 1171439036

2017-02-18

  • 9:34am, gate valve closed, pumps stopped, venting
  309   Thu Feb 16 10:07:59 2017 GabrieleGeneralMeasurementsS1600491

2017-02-16

  • 10:06am, in chamber CR0, balanced
  • 10:07am, roughing pump on
  • 10:31am, turbo pump on
  • Excitations
    • Quiet time before excitation: 1171326606
      Excitation (broad band) at 1171326638 (60 s)
      Quiet time after excitation: 1171326700

    • Quiet time before excitation: 1171328530
      Excitation (broad band) at 1171328562 (60 s)
      Quiet time after excitation: 1171328624

    • Quiet time before excitation: 1171330454
      Excitation (broad band) at 1171330487 (60 s)
      Quiet time after excitation: 1171330549

    • Quiet time before excitation: 1171332379
      Excitation (broad band) at 1171332411 (60 s)
      Quiet time after excitation: 1171332473

    • Quiet time before excitation: 1171334303
      Excitation (broad band) at 1171334335 (60 s)
      Quiet time after excitation: 1171334397

    • Quiet time before excitation: 1171336227
      Excitation (broad band) at 1171336259 (60 s)
      Quiet time after excitation: 1171336321

    • Quiet time before excitation: 1171338151
      Excitation (broad band) at 1171338184 (60 s)
      Quiet time after excitation: 1171338246

    • Quiet time before excitation: 1171340076
      Excitation (broad band) at 1171340108 (60 s)
      Quiet time after excitation: 1171340170

2017-02-17

  • 8:36am pump stopped
  308   Thu Feb 16 09:47:29 2017 GabrieleGeneralMeasurementsSummary of coating runs carried out at Montreal
Substrate temperature Serial numbers
room temperature 457 458 490 492
150 C 489 491
250 C 447 456
400 C 459 461
480 C 448 453

 

  307   Tue Feb 14 15:50:23 2017 GabrieleGeneralMeasurementsS1600519 S1600520 S1600521 S1600522

New substrates from Mark Optics, round, with polished edges

2017-02-14

  • 3:35pm in new chamber
    • S1600519 in bay 1
    • S1600520 in bay 2
    • S1600521 in bay 3
    • S1600522 in bay 4
  • 3:38pm, roughing pump on, clamps on
  • 3:48pm, turbo pump on
  • Excitations:
    • Quiet time before excitation: 1171158544
      Excitation (broad band) at 1171158579 (60 s)
      Quiet time after excitation: 1171158644

    • Quiet time before excitation: 1171173074
      Excitation (broad band) at 1171173109 (60 s)
      Quiet time after excitation: 1171173174

    • Quiet time before excitation: 1171187604
      Excitation (broad band) at 1171187639 (60 s)
      Quiet time after excitation: 1171187704

  • NOTE: bay 4 was not excited

2017-02-15

  • 3:16pm, gate valve closed, pump stopped, venting
  306   Tue Feb 14 14:47:00 2017 GabrieleGeneralMeasurementsS1600495

2017-02-14

  • 2:32pm, in chamber (CR0), balanced
  • 2:33pm roughing pump on
  • 2:45pm, turbo pump on
  • Excitations:
    • Quiet time before excitation: 1171161389
      Excitation (broad band) at 1171161421 (60 s)
      Quiet time after excitation: 1171161483

    • Quiet time before excitation: 1171172313
      Excitation (broad band) at 1171172345 (60 s)
      Quiet time after excitation: 1171172407

    • Quiet time before excitation: 1171183237
      Excitation (broad band) at 1171183269 (60 s)
      Quiet time after excitation: 1171183331

    • Quiet time before excitation: 1171194161
      Excitation (broad band) at 1171194193 (60 s)
      Quiet time after excitation: 1171194255

    • Quiet time before excitation: 1171205085
      Excitation (broad band) at 1171205117 (60 s)
      Quiet time after excitation: 1171205179

2017-02-15

  • 3:19pm, pumps stopped, venting
  305   Tue Feb 14 10:55:13 2017 GabrieleGeneralDaily ProgressSomething fishy with bay 4 of the new setup

I did two set of measurements with the new coated samples from Montreal. I reshuffled the position in the two measurements. In both cases, the measurement being performed in bay 4 was bad, in the sense that it was very hard to see excited modes. Since the two measurements were carried out with two different disks, it's clear it is a problem with that setup.

SOLVED: there was a connection problem for the DAC output signal controlling the switch

REALLY SOLVED: it was not a cabling issue. The power supply for the switching box had the current limiter on: when all four switches are closed, the box drain about 270mA, which is more than the limit of 250mA. Therefore the power supply voltage dropped and only three switches were actually closed. I switched the power supply to 500mA range and maxed the current limit. Now all four switches are working properly

  304   Sat Feb 11 16:22:26 2017 GabrieleMechanicsDaily ProgressTranslation stage to move retaining rings

The ring motion up and down was not very smooth, again due to friction on the centering pins.

So, after centering the rings using the pins and securing the rings to the translation stage, I removed all pins.

Now the motion up and down is very smooth.

I still have to fine tune the amount of steps that are needed to go up and down.

However, initial tests don't show a good repeatability of the positioning. My main suspect is that the vibration caused by the picomotor cause the disks to slip on the silicon lens. Indeed, when the disks are sitting on the rings, one can clearly hear them "rattle".

Quote:

This afternoon I installed the picomotor and the translation stage that will be used to move the retaining rings up and down. No partciular problem: I only had to add some small aluminum foil shims between the ear of some rings and the square plate, to make the rings as horizontal as possible.

I tested the motion: with 300000 steps it's possible to move the rings all the way from the parked (down) position, to the up position. I also checked that when the rings are up, I can place four substarates and they fall properly into the alignment groove. Since the maximum speed of the picomotor is 2000 steps/s, it takes 150 seconds to move up and down the ring. 

Finally, positive steps means that the rings are moving up, negative that they're moving down.

I raeligned the optical levers to the position I obtained by centering the samples with the rings. I haven't tested the repeatability yet.

 

  303   Fri Feb 10 17:16:28 2017 GabrieleMechanicsDaily ProgressTranslation stage to move retaining rings

This afternoon I installed the picomotor and the translation stage that will be used to move the retaining rings up and down. No partciular problem: I only had to add some small aluminum foil shims between the ear of some rings and the square plate, to make the rings as horizontal as possible.

I tested the motion: with 300000 steps it's possible to move the rings all the way from the parked (down) position, to the up position. I also checked that when the rings are up, I can place four substarates and they fall properly into the alignment groove. Since the maximum speed of the picomotor is 2000 steps/s, it takes 150 seconds to move up and down the ring. 

Finally, positive steps means that the rings are moving up, negative that they're moving down.

I raeligned the optical levers to the position I obtained by centering the samples with the rings. I haven't tested the repeatability yet.

 

  302   Thu Feb 9 14:49:51 2017 GabrieleGeneralMeasurementsS1600489 S1600490 S1600491 S1600492

2017-02-09

  • 2:30pm, samples installed in the chamber:
    • S1600489 in bay 1
    • S1600490 in bay 2
    • S1600491 in bay 3
    • S1600492 in bay 4
  • 2:35pm, roughing pump on
  • 2:45pm, pressure is <1 Torr, turbo pump on
  • 4:19pm, pressure is 7.2e-6:
    • but I forgot to clamp the lid!
    • added four clamps at 4:22pm
    • pressure seems to be going down again
  • Excitations
    • Quiet time before excitation: 1170737383
      Excitation (broad band) at 1170737418 (60 s)
      Quiet time after excitation: 1170737483

    • Quiet time before excitation: 1170739313
      Excitation (broad band) at 1170739349 (60 s)
      Quiet time after excitation: 1170739414

    • Quiet time before excitation: 1170741244
      Excitation (broad band) at 1170741279 (60 s)
      Quiet time after excitation: 1170741344

    • Quiet time before excitation: 1170743174
      Excitation (broad band) at 1170743210 (60 s)
      Quiet time after excitation: 1170743275

    • Quiet time before excitation: 1170745105
      Excitation (broad band) at 1170745140 (60 s)
      Quiet time after excitation: 1170745205

    • Quiet time before excitation: 1170747035
      Excitation (broad band) at 1170747070 (60 s)
      Quiet time after excitation: 1170747135

    • Quiet time before excitation: 1170748965
      Excitation (broad band) at 1170749000 (60 s)
      Quiet time after excitation: 1170749065

    • Quiet time before excitation: 1170750896
      Excitation (broad band) at 1170750931 (60 s)
      Quiet time after excitation: 1170750996

2017-02-10

  • 11:37am, gate valve closed, pumps off, venting

2017-10-13

  • 8:30am, in chamber, balanced
    • S1600492 in bay 1
    • S1600491 in bay 2
    • S1600490 in bay 3
    • S1600489 in bay 4
  • 8:34am roughing pump on, clamps on lid
  • 8:46am turbo pump on
  • Excitations
    • Quiet time before excitation: 1171048567
      Excitation (broad band) at 1171048602 (60 s)
      Quiet time after excitation: 1171048667

    • Quiet time before excitation: 1171049897
      Excitation (broad band) at 1171049933 (60 s)
      Quiet time after excitation: 1171049997

    • Quiet time before excitation: 1171051227
      Excitation (broad band) at 1171051262 (60 s)
      Quiet time after excitation: 1171051327

    • Quiet time before excitation: 1171052557
      Excitation (broad band) at 1171052592 (60 s)
      Quiet time after excitation: 1171052657

    • Quiet time before excitation: 1171053887
      Excitation (broad band) at 1171053922 (60 s)
      Quiet time after excitation: 1171053987

    • Quiet time before excitation: 1171055217
      Excitation (broad band) at 1171055252 (60 s)
      Quiet time after excitation: 1171055317

    • Quiet time before excitation: 1171056547
      Excitation (broad band) at 1171056582 (60 s)
      Quiet time after excitation: 1171056647

    • Quiet time before excitation: 1171057877
      Excitation (broad band) at 1171057912 (60 s)
      Quiet time after excitation: 1171057977

  • Chamber opened at about 2:30pm, samples out
  301   Thu Feb 9 11:35:27 2017 GabrieleOpticsConfigurationQPD calibration

This morning I measured the beam profiles at the QPD positions. As expected, the beams are not gaussian there, since we are seeing the interference of the reflections from the two faces of the disks. Nevertheless, the measured sizes are

  Beam radius [microns]
QPD1 302
QPD2 338
QPD3 270
QPD4 401

Here are the images of the beams:

The arm lever lengths (distance from the disk surface to the QPD) can be estimated from the optical drawing:

  Distance disk to QPD [mm]
QPD1 1540
QPD2 1813
QPD3 1587
QPD4 1652

The optical gain (normalized QPD signal over disk surface angle) is given by

g = \frac{4 L}{w} \sqrt{\frac{2}{\pi}}

  Gain 1/rad
QPD1 16300
QPD2 17100
QPD3 18800
QPD4 13150

The uncertaint in those numbers is quite large, both from the beam size and from the arm lever. Anyhow, I'm using the average to have a rough calibration of the QPD signals in terms of disk surface angular motion. The value I plugged in into the X_NORM filter banks is 16300 /rad. Therefore now the signals *NORM_OUT_DQ are calibrated in radians (deflection of the disk surface).

Finally, I also measured the profiles of the beams going into the chamber, somewhere before the 2" folding mirror. They have nice gaussian shapes

  300   Thu Feb 9 09:30:52 2017 GabrieleOpticsDaily ProgressTwo laser installed, setup aligned

The lasers are behaving well, there is no high noise or wandering lines. The spectrum below is taken in air: that explains the excess of noise in the few kHz region.

Quote:

Today I swapped out the 8mW laser and installed two 2.5 mW lasers. I rebuilt the input part of the optical levers and re-aligned everything. See below for a picture of the new setup: red beams are input, yellow beams are output. I also installed a protective screen all around the table, to abvoid any suprios beam to get out.

 

  299   Thu Feb 9 09:10:17 2017 Gabriele, LarryElectronicsConfigurationPrivate network

I reconfigured the powerstrip and the two Newport controllers to use static IP address in the new 10.10.10.X network, using the workstation as gateway. All scripts updated and working

Quote:

This morning Larry set up a network switch to create a local network for the power strip and the two Newport picomotor controllers. The laboratory workstation serves as gateway between the networks.

I still have to configure the power strip and the picomotor controllers to use the new static IP address.

 

  298   Thu Feb 9 08:35:24 2017 GabrieleElectronicsConfigurationRemoved ESD bias path to model CR0

Removed, since iit was not useful to improve the actuation authority.

Quote:

I added to the model CR0 an additional bias path for the ESD driver:

 

  297   Wed Feb 8 17:06:11 2017 Gabriele, LarryElectronicsConfigurationPrivate network

This morning Larry set up a network switch to create a local network for the power strip and the two Newport picomotor controllers. The laboratory workstation serves as gateway between the networks.

I still have to configure the power strip and the picomotor controllers to use the new static IP address.

  296   Wed Feb 8 17:01:01 2017 GabrieleOpticsDaily ProgressTwo laser installed, setup aligned

Today I swapped out the 8mW laser and installed two 2.5 mW lasers. I rebuilt the input part of the optical levers and re-aligned everything. See below for a picture of the new setup: red beams are input, yellow beams are output. I also installed a protective screen all around the table, to abvoid any suprios beam to get out.

  295   Tue Feb 7 16:16:37 2017 GabrieleOpticsDaily ProgressLasers

The high power lasers I tested so far (the Thorlabs 21mW and the JDSU 1125P) are noisy: they both have wandering lines that from time to time are alised down into the base band, destroing the measurement. 

I have three JDSU 1103P units: two of them dlived about 2.5 mW, the third one delivers about 1.4 mW. One of the 2.5mW was installed in the test setup. I swapped it out with the 1.4 mW, so now I have two good 2.5 mW laser. My plan is to modify the new setup to use those two lasers in parallel, splitting each one in two, for a total of four beams of about 1.2 mW each.

The new optical layout is atttached.

  294   Tue Feb 7 10:03:35 2017 GabrieleGeneralMeasurementsS1600496

2017-02-07

  • 10:02am in chamber, balanced
  • 10:03am roughing pump on
  • 10:30am turbo pump on
  • Excitations (they didn't work, I forgot to switch on the noise!!)
    • Quiet time before excitation: 1170548335
      Excitation (broad band) at 1170548367 (60 s)
      Quiet time after excitation: 1170548429

    • Quiet time before excitation: 1170559259
      Excitation (broad band) at 1170559291 (60 s)
      Quiet time after excitation: 1170559353

    • Quiet time before excitation: 1170570183
      Excitation (broad band) at 1170570216 (60 s)
      Quiet time after excitation: 1170570278

    • Quiet time before excitation: 1170581108
      Excitation (broad band) at 1170581140 (60 s)
      Quiet time after excitation: 1170581202

    • Quiet time before excitation: 1170592032
      Excitation (broad band) at 1170592064 (60 s)
      Quiet time after excitation: 1170592126

    • Quiet time before excitation: 1170602956
      Excitation (broad band) at 1170602989 (60 s)
      Quiet time after excitation: 1170603051

  • Excitations:

    • Quiet time before excitation: 1170638328
      Excitation (broad band) at 1170638360 (60 s)
      Quiet time after excitation: 1170638422

    • Quiet time before excitation: 1170649252
      Excitation (broad band) at 1170649285 (60 s)
      Quiet time after excitation: 1170649347

    • Quiet time before excitation: 1170660177
      Excitation (broad band) at 1170660209 (60 s)
      Quiet time after excitation: 1170660271

    • Quiet time before excitation: 1170671101
      Excitation (broad band) at 1170671133 (60 s)
      Quiet time after excitation: 1170671195

    • Quiet time before excitation: 1170682025
      Excitation (broad band) at 1170682057 (60 s)
      Quiet time after excitation: 1170682119

 

2017-02-09

  • 4:11pm, pumps off

 

  293   Mon Feb 6 16:22:47 2017 GabrieleGeneralMeasurementsS1600472 S1600478 S1600473 S1600480
  • In the new chamber
  • Excitations:
    • Quiet time before excitation: 1170443490
      Excitation (broad band) at 1170443523 (60 s)
      Quiet time after excitation: 1170443586

    • Quiet time before excitation: 1170454416
      Excitation (broad band) at 1170454449 (60 s)
      Quiet time after excitation: 1170454512

    • Quiet time before excitation: 1170465342
      Excitation (broad band) at 1170465375 (60 s)
      Quiet time after excitation: 1170465438

 

2017-02-07

  • 9:36am gate valve closed, pumps off

 

 

 

  292   Mon Feb 6 14:09:07 2017 GabrieleGeneralMeasurementsFirst set of parallel measurements completed

The new laser is still acting up a bit, with a wandering line moving sometimes inside the band. Nevertheless, I could perform the first complete measurement of four samples in parallel.

Everything went as expected, there is no visible cross coupling between modes of different disks. The MATLAB code for the analysis is ready and working.

Here are the results:

  291   Mon Feb 6 11:19:13 2017 GabrieleOpticsDaily ProgressLaser swap

The Thorlabs laser has been misbehaving for the whole weekend. Even after many days being continuosly on, the wandering line is still moving all over the frequencies.

So this morning I swapped in a JDSU 1125P borrowed from the 40m lab, which provides about 6.8 mW of power. I tested it over the weekend on a separate test table, and after one day or so of operation the power looks reasonably stable. Now it's been on for a few hours: there is still a line moving around, but it's slowing down and hopefully setting down in a good place.

I started a series of test measurements on the samples that were already installed.

  • Quiet time before excitation: 1170443490
    Excitation (broad band) at 1170443523 (60 s)
    Quiet time after excitation: 1170443586

 

  290   Mon Feb 6 08:37:54 2017 GabrieleGeneralMeasurementsS1600495

2017-02-06

  • 8:35am in chamber, balanced
  • 8:36am roughing pump on
  • 8:50am tubo pump on
  • Excitations: (they didn't work, I forgot to switch on the noise!!)
    • Quiet time before excitation: 1170460053
      Excitation (broad band) at 1170460085 (60 s)
      Quiet time after excitation: 1170460147

    • Quiet time before excitation: 1170470977
      Excitation (broad band) at 1170471010 (60 s)
      Quiet time after excitation: 1170471072

    • Quiet time before excitation: 1170481902
      Excitation (broad band) at 1170481935 (60 s)
      Quiet time after excitation: 1170481997

    • Quiet time before excitation: 1170492827
      Excitation (broad band) at 1170492860 (60 s)
      Quiet time after excitation: 1170492922

    • Quiet time before excitation: 1170503752
      Excitation (broad band) at 1170503785 (60 s)
      Quiet time after excitation: 1170503847

    • Quiet time before excitation: 1170514677
      Excitation (broad band) at 1170514710 (60 s)
      Quiet time after excitation: 1170514772

2017-02-07

  • 09:36am pumps off

 

 

  289   Wed Feb 1 16:58:10 2017 GabrieleGeneralCharacterizationExcitation tests

The excitation is working fine. However, there is a large cross coupling in the excitation between channels: so if I switch on only one of the ESD paths, I actually excite all other disks too.  It might be due to the common ground or to the fact that the cables run close to each other. This needs some investigation, but it's not a big issue for the moment being.

On the other hand, the optical levers are very well decoupled: each one sees a different set of modes. So there is no measurable cross coupling between the disks or the readout.

There seems to be something fishy with the Y picomotor of QPD3: it doesn't always move in the same direction for the same set of steps. Some investigations needed here too. Autocentering might fail, but it's still possible to center it manually.

Excitation at 4:56pm (quiet time before excitation 1170032165, quiet time after excitation 1170032234).

Another excitation at 8:30am (2017-02-02) (quiet time before excitation 1170088185, quiet time after excitation 1170088373)

  288   Wed Feb 1 15:35:30 2017 GabrieleGeneralDaily Progressexcitation not working - FIXED

My bad, a cable was disconnected.

Quote:

 

Finally, I tried to excite the disks, but I couldn't get any motion of the optical lever beams. To be investigated, there might simply be some cables disconnected.

  287   Wed Feb 1 15:23:42 2017 GabrieleOpticsNoise huntingWandering line is due to the laser

The wandering line I mentioned in my previous elog, which is spoiling most of the sensitivity, turns out to be power noise of the laser. 

I used a Thorlabs PDA100 and a SR785 to measure the power noise out of the laser directly, and saw a huge forest of peaks above 20kHz. Among them, a couple of peaks are moving up and down in frequency very fast. The plot below compares two different times of the Thorlabs HNL210L laser (the new one, 21 mW) with the old JTSU laser we are using for the test setup:

The noise of the new laser is cleary much larger (even after the laser has been on for some time) and non stationary. This is a big issue for us. I will contact Thorlabs to inquire if this behavior is normal.

The attached video file shows the peaks dancing around on the SR785 screen.

  286   Tue Jan 31 16:55:17 2017 GabrieleGeneralDaily ProgressImproved autocenter, excitation not working, wandering line

The autocenter script wasn't working in a very robust way (sometimes the socket connection to the controller failed, some times no motion was obtained after issuing a command). So I rewrote the interface to the Newport controller using the http server interface. The code is in picomotor8742_http.py. This version seems much more robust.

There is a large wandering line that spans all frequencies. Not sure what the origin is, but it will need some noise hunting. Here are spectrograms of all four QPD X signals. The line is visible in all of them, at the same frequency. So it's definitely something external coupling into the light or the QPD electronics. It's not visible in the sum of the QPD quadrants, but maybe just because it's buried in noise.

Finally, I tried to excite the disks, but I couldn't get any motion of the optical lever beams. To be investigated, there might simply be some cables disconnected.

 

  285   Tue Jan 31 16:50:55 2017 Gabriele, AlenaGeneralVacuumFirst pump-down with setup

This afternoon we started the pump-down with all the system installed into the chamber. Unfortunately the IGM vacuum gauge isn't working, so we can't be sure what the pressure is. To be fixed

  284   Tue Jan 31 11:21:44 2017 GabrieleMechanicsDaily ProgressRetaining ring mechanics

All parts for the motion of the retaining rings have been received and are ok. We're going to clean and bake them. 

  283   Tue Jan 31 09:03:12 2017 GabrieleElectronicsConfigurationAuto centering script for the new setup

I wrote an autocenter script for the four QPD in the new setup (autocenter14.py) and renamed the script for the old chamber (autocenter0.py).

Tested and working properly, with network connection to the picomotor controllers. Be aware that if the picomotor controllers are switched off, their IP address might change.

  282   Mon Jan 30 15:16:54 2017 GabrieleGeneralDaily ProgressFour samples in chamber
  • checked that the high voltage paths are working:
    • the DAC signal is properly received and amplified by the Trek 2220 HV amplifier
    • the HV switch box is working as expected: I can switch on and off each path individiually using the DAC signals
  • installed four samples (refer to the optical drawing for the numbering)
    • S1600472 in bay 1
    • S1600478 in bay 2
    • S1600473 in bay 3
    • S1600480 in bay 4

  • balanced all samples and centered all optical levers. There is a problem with the fifth connector in the ADC interface board (or maybe with one ADC channel). So one of the quadrants of QPD4 was not working. I moved the connector to number 6 and updated the model. Everything looks fine now.
  • the power in the four QPD is quite diverse: this is not unexpected, since it depends on the interference of the reflection from the two surfaces of the disk

  • installed the picomotor controllers on the bench, connected them to the net using the switch on the top of the clean room. For the moment being they are using DHCP.
  • connected all picomotors to the controllers.
    • Bottom controller, from left to right: QPD1x, QPD1y, QPD2x, QPD2y
    • Top controller, from left to right: QPD3x, QPD3y, QPD4x, QPD4y
  • tested the remote control and motion of all picomotors

ELOG V3.1.3-