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ID Date Author Type Categoryup Subject Text Attachments
  407   Tue Aug 15 00:09:01 2017 ZachElectronicsModelingESD Improvements2017-08-14


I did my
best to increase the excitation in the higher
order modes. By making the ESD narrower (a
 10x 
  409   Tue Aug 15 16:43:58 2017 ZachElectronicsModelingUnchanged Mode Insight2017-08-15


It appears
to me that the major factor limiting the
improvement of the modes that either remain
 Double.pdfThin.pdfOriginal.pdf 
  411   Wed Aug 16 10:04:24 2017 ZachElectronicsModelingESD along edge2017-08-16


I placed
created a very narrow ESD placed along the
edge of the sample. The thought behind this
 edge.jpgoverlay15.jpgoverlay15.jpg 
  412   Wed Aug 16 11:36:13 2017 ZachElectronicsModelingMiddle ESD 2017-08-16


I created
a model with a drive offset in the middle.
It improved one of the modes by a factor
 middle.jpgoverlay23.jpgoverlay23.jpg 
  414   Wed Aug 16 16:05:09 2017 ZachElectronicsModelingTwo ESD First test2017-08-16


I created
a model with two ESD's, essentially a
combination of my previous two attempts with
 Double_Modes.jpgTwo.jpgTwoESD_geo.png 
  415   Thu Aug 17 14:19:04 2017 ZachElectronicsModelingTwo ESD Optimization2017-08-17


I ran a
sweep of the position of the middle ESD to
determine the optimal arrangement. From the
 17x 
  416   Thu Aug 17 23:34:51 2017 ZachElectronicsModelingOptimized ESD Drawing2017-08-17


I made a
drawing of the Optimal ESD design. The bottom
combs (right hand in the rotated image) are
 OptimizedESD.pdf 
  417   Fri Aug 18 10:50:53 2017 ZachElectronicsModelingESD's with positive voltage2017-08-18


With both
electrodes driven at a positive voltage,
the results are still an improvement over
 two_positive.jpg 
  419   Fri Aug 18 14:15:47 2017 ZachElectronicsModelingSame Voltage ESD Sweep2017-08-18


I ran a
sweep of the central position in the two
ESD setup with both set at the same voltage.
 two_positive_ratio_sweep.pdf-2mm_two_positive.jpg3mm_two_positive.jpg-2mm_two_positive.jpg 
  420   Fri Aug 18 15:10:23 2017 Zach, GabrieleElectronicsModelingESD prototype2017-08-18


We created
a prototype of PCB for the ESD design. Unfortunately
the orientation of the two combs was flipped,
 Crime_ESD_Zach_prototype.pdf 
  170   Wed Nov 9 15:32:11 2016 GabrieleGeneralNoise huntingNoise below 2 kHz is not due to the roughing pump, but to the clean air filtersThe two spectra below show basically no
difference (blue roughing pump on, red, roughing
pump off)
 Screenshot-1.pngScreenshot.png 
  176   Thu Nov 10 17:04:05 2016 GabrieleGeneralNoise huntingTemporary second QPDThis morning I installed temporarily a
second QPD to monitor the input beam. The
goal was to understand where the vibrations
 2016-11-10_10.56.06.jpgspectra.pngcoherence_x.png 
  181   Sun Nov 13 10:11:19 2016 GabrieleGeneralNoise huntingNoise due to airThe plot below compares the QPD signal
spectra in different configurations (roughing
pump on/off, air on/off).
 air_noise.pngair_zoom.png 
  209   Wed Nov 23 08:55:41 2016 GabrieleGeneralNoise hunting"Advanced" vibration isolationIn normal conditions the RMS of the QPD
signals is dominated by the 58 Hz line generated
by the roughing pump. Also, when the modes
 2016-11-22_15.22.13.jpgvibration_isolation.png 
  216   Tue Nov 29 17:02:06 2016 GabrieleFacilityNoise huntingSuspending the roughing pumpI suspended the roughing pump with four
springs. The reduction of the 58 Hz peak
is similar to what I got when the pump was
 2016-11-29_11.08.17.jpg2016-11-29_11.12.35.jpg2016-11-29_11.08.21.jpg 
  287   Wed Feb 1 15:23:42 2017 GabrieleOpticsNoise huntingWandering line is due to the laserThe wandering line I mentioned in my previous
elog, which is spoiling most of the sensitivity,
turns out to be power noise of the laser. 
 laser_noise_rin.pngUntitled.avi 
  326   Thu Mar 2 11:27:47 2017 GabrieleGeneralNoise huntingTurbo pump of CR0 pollutes CR1The turbo pump of the CR0 chamber runs
at 833 Hz. It causes vibrations that pollute
the measurements in the CR1-4 chamber. In
 Screenshot.png 
  128   Tue Sep 27 08:53:46 2016 GabrieleGeneralVacuumEtched disk installedInstalled the etched disk: using manually
the centering ring allowed me to get the
beam on the QPD. A couple of taps to the
  
  133   Mon Oct 17 10:50:50 2016 GabrieleGeneralVacuumNo sign of problems in the electrostatic driveI opened the chamber and took the etched
disk out. Inspection of the electrostatic
drive does not show any sign of burn or damage.
  
  142   Fri Oct 21 14:03:17 2016 GabrieleGeneralVacuumRoughing pump movedI moved the roughing pump out of the clean
room, adding an extension hose.

 
 compare_pump.pngimprovement_pump.png 
  165   Mon Nov 7 11:27:16 2016 GabrieleGeneralVacuumTurbo pump excites some resonance at 58 HzI looked into a couple of turbo pump switch
on periods, and in both cases when the pump
speed hits 58 Hz, a resonance is excited.
  
  186   Mon Nov 14 11:28:33 2016 GabrieleGeneralVacuumViton padsI added three 1"x1" viton pads
below the base plate, and realigned the entire
optical system to the horizontal reference
 2016-11-14_10.41.47.jpg2016-11-14_10.41.57.jpgviton.png 
  195   Thu Nov 17 12:06:39 2016 GabrieleGeneralVacuumSwitching on the IGM moves the diskHere's a trend of the QPD signals when
the IGM was turned on:

 igm_on.png 
  264   Thu Jan 19 07:32:33 2017 AlenaGeneralVacuumNew chamber first pimp downThe new chamber was build. The first attempt
to pump down was unsuccessful because of
dislocated lid. After the lit was placed
 unnamed.jpg 
  265   Thu Jan 19 12:49:17 2017 GabrieleFacilityVacuumSkyhook installedThe SkyHook has been put in place and bolted
down to the floor.

 IMG_4241.JPGIMG_4241.JPGIMG_4241.JPGIMG_4241.JPG 
  267   Thu Jan 19 14:27:02 2017 AlenaGeneralVacuumFirst vacuum test new chamberTurbo pump controller (new chamber) was
configured. Need to reduce the frequency
or setup a standby mode. First pump down:
 20170119.png 
  285   Tue Jan 31 16:50:55 2017 Gabriele, AlenaGeneralVacuumFirst pump-down with setupThis afternoon we started the pump-down
with all the system installed into the chamber.
Unfortunately the IGM vacuum gauge isn't
  
  498   Tue Mar 27 16:37:22 2018 GabrieleGeneralVacuumTurbo pump for test chamber CR0 set pointI changed the set point of the test chamber
turbo pump to 666 Hz. This was done
by setting the "standby rotation speed"
  
  517   Thu Apr 12 10:33:06 2018 GabrieleGeneralVacuumRead-out of vacuum gaugesI failed to interface in a reliable way
the datalogger with Linux. So i hooked up
the four analog outputs of the vacuum gauge
 gauges.pngpressures.png 
  703   Tue May 28 15:48:42 2019 AlenaGeneralVacuumLow pressure gauge exchangeAfter venting the vacum chamber (CR14)
a few times, checking for leaks and trying
to tune settings to the gauges controller,
  
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