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New entries since:Wed Dec 31 16:00:00 1969
ID Date Author Type Category Subjectdown Text Attachments
  62   Tue Jul 26 11:45:03 2016 GabrieleElectronicsCharacterizationHigh frequency noise budgetJust to confirm that my noise estimates
make sense, here's a plot of the not-normalized
QPD signal that gives the X motion (sum and
  57   Thu Jul 21 14:58:26 2016 GabrieleElectronicsGeneralGlitches are of digital originSo here's the final proof that the
glitches I see are digital:

There is a positive jump
  54   Tue Jul 19 20:19:38 2016 GabrieleElectronicsConfigurationGlitches are a digital artifactThe glitches I saw in the data happens
roughly every second, even though not
exactly on the second. They are suddend jumps
  56   Thu Jul 21 12:10:14 2016 GabrieleGeneralDaily ProgressGlitch huntingYesterday I could clearly see the glitches
as jumps in the time domain plot of X and
Y signals, and trace them to somewhat harder
  402   Thu Aug 10 10:47:54 2017 ZachElectronicsModelingGeometry Ratios2017-08-10

The attached
plots compare the new and old geometries
with .5 mm and 1 mm sample gaps. They are
  873   Tue Jun 9 11:04:28 2020 GabrieleGeneralMeasurementsGaAs S16008052020-06-09

11:00 am
in chamber

GaAs in CR1
in CR2

11:04 am
  476   Mon Mar 5 11:03:18 2018 Gabriele, AnthonyGeneralMeasurementsFused silica substrated for metallic glass tests2018-03-05

in chamber:

AK_01 in CR1
in CR2
AK_03 in CR3
  356   Tue Jun 27 14:17:47 2017 ZachElectronicsModelingFurther plots and improving models2017-06-27

I built
a new model of the ESD to determine whether
or not the spikes in the electric field at
  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
  278   Thu Jan 26 17:06:59 2017 GabrieleGeneralDaily ProgressFour fold measurement system installationToday I installed the four GeNS systems
into the chamber, connected the ESD to the
HV feedthrough and put the periscopes in
  368   Fri Jul 14 16:43:24 2017 ZachElectronicsModelingForce profile matlab script2017-07-14

I have completed
a rough, but functioning script that calculates
the modal force profiles. The force values
  363   Wed Jul 5 12:01:51 2017 ZachElectronicsModelingForce plots-Correct plots, force issue2017-07-05

I sorted
out my mathematical lapse in logic and computed
the correct force profiles in the perpendicular
  364   Wed Jul 5 16:40:51 2017 ZachElectronicsModelingForce disparity-improvement2017-07-05

In order
to improve my data I shrunk the region of
the finer meshing slightly and made the mesh
  87   Tue Aug 16 11:57:03 2016 GabrieleElectronicsConfigurationFixed cymac3 network and time issueThe cymac3 internal clock was off by about
10 seconds. When I tried to start the NTP
service, I found out that the cymac3 couldn't
  82   Sat Aug 13 14:05:02 2016 GabrieleGeneralDaily ProgressFirst work on the measurement user interfaceToday I started programming part of the
user interface that will be used to perform
the measurements. Not much implemented so
  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:
  292   Mon Feb 6 14:09:07 2017 GabrieleGeneralMeasurementsFirst set of parallel measurements completedThe new laser is still acting up a bit,
with a wandering line moving sometimes inside
the band. Nevertheless, I could perform the
  92   Sat Aug 20 17:01:10 2016 GabrieleGeneralDaily ProgressFirst ring down measurementsEverything is working pretty well. This
morning the pressure was about 1.2e-6 Torr.
I connected the high voltage amplifier and
  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
  53   Tue Jul 19 17:21:48 2016 GabrieleGeneralDaily ProgressFirst modes excited!We can't generate any arbitary signal
with the real time model, since awg is not
working properly yet. For the moment being
  93   Sat Aug 20 22:18:26 2016 GabrieleGeneralDaily ProgressFirst measured QsUsing the first ring down of the day (GPS 1155754513
+ 3600 seconds), I computed the amplitude
of each of the modes already identified,
  49   Mon Jul 18 17:46:04 2016 GabrieleGeneralDaily ProgressFirst look at QPD signalsHere's the first spectrum of the QPD
X and Y signals, acquired with the digital
system. Roughing and turbo pumps are still
  107   Mon Sep 12 16:00:06 2016 GabrieleGeneralDaily ProgressFirst fully automated measurements of ring downI finished the first version of the automation
software to measure the ring down of the
disk modes. I tested it with the new substrate
  26   Wed Jun 29 16:44:17 2016 GabrieleGeneralConfigurationFirst disk eigenfrequencyThe following table shows the lowest eigenfrequency
(Hz) for different sizes of disks

  213   Mon Nov 28 16:02:16 2016 GabrieleGeneralGeneralExpected frequencies for the MIT samples

  105   Thu Sep 1 02:13:33 2016 GabrieleOpticsCharacterizationExpected frequencies for the 75 mm disks with flatsHere are the nominal parameters of the
disk with flats

  422   Thu Aug 24 07:40:33 2017 GabrieleGeneralMeasurementsExcitations with new ESD2017-08-23


time before excitation: 1187577794
Excitation broadband: 1187577826
  424   Fri Aug 25 07:25:32 2017 GabrieleGeneralMeasurementsExcitations with new ESDThe results show very low Q values, so
we suspected some issues. Yesterday we openend
the chamber and moved the ESD up, as high
  425   Fri Aug 25 19:29:07 2017 GabrieleGeneralMeasurementsExcitations with new ESDNew set of excitations after raising the

Quiet time before excitation:
  289   Wed Feb 1 16:58:10 2017 GabrieleGeneralCharacterizationExcitation testsThe excitation is working fine. However,
there is a large cross coupling in the excitation
between channels: so if I switch on only
  118   Tue Sep 20 16:43:58 2016 GabrieleGeneralGeneralExcitation and ring downThe pressure is at abour 3e-6 Torr. I centered
the QPD and started an excitation. The HV
amplifier manual states that the driver can
  119   Wed Sep 21 08:12:13 2016 GabrieleGeneralGeneralExcitation and ring downNew excitation (2000V) at about 8:06am.
Had to recenter the QPD again after the excitation.

Engaged the 500Hz high pass filter
  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
  123   Thu Sep 22 15:00:49 2016 GabrieleElectronicsConfigurationEpics values now saved to framesI was looking at some past trend data and
discovered that EPICS values were not written
to the frames. I added the following two
  125   Fri Sep 23 08:33:39 2016 GabrieleElectronicsConfigurationEpics values now saved to framesNow EPICS values are saved to frames, but
they are all zero! I noticed that we always
had the same problems with the cymac2 too.
  129   Tue Sep 27 14:54:53 2016 GabrieleElectronicsConfigurationEpics values now saved to framesApparently, there was a mismatch in the
configuration, and DAQD was adding a wonderful
16 Hz comb all over the spectrum.
  43   Fri Jul 15 16:05:07 2016 GabrieleElectronicsDaily ProgressElectrostatic actuator installedUsing the already installed high voltage
feedthrough, I cabled one of the electrostatic
actuators (1mm gap between electrodes) and
  344   Tue May 16 13:44:01 2017 GabrieleGeneralGeneralEffect of meshing on dilution factor simulationI ran a series of COMSOL simulations to
compute the dilution factors of a coated
disk with the dimensions we are currently
  243   Thu Dec 15 11:58:55 2016 GabrieleGeneralGeneralEffect of clip fingerprints on dilution factorThe disks coated at Montreal are hold with
three small clips. Therefore there are three
small regions close to the edge that are
  395   Tue Aug 8 09:58:34 2017 GabrieleGeneralMeasurementsEffect of assist beam on tantala coatings - no post deposition annealing ntroduction

A set of substrates
have been coated by the Colorado State University
Fort Collins group, with ~500 nm tantala
  396   Tue Aug 8 10:18:30 2017 GabrieleGeneralMeasurementsEffect of assist beam on tantala coatings - after post deposition annealing Introduction

The same set of
samples described in the previous
entry have been annealed at 500C for
  145   Mon Oct 24 14:33:46 2016 GabrieleGeneralMeasurementsEffect of annealing: Q increasesS1600439 has been measured as received
(before annealing, elog
137) and after annealing (elog
  114   Thu Sep 15 15:15:10 2016 GabrieleGeneralGeneralEdge effect on lossesI made a COMSOL model that can compute
the distribution of elastic energy for each
mode, dividing it into:
  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
  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,
  405   Thu Aug 10 13:36:08 2017 Gabriele, ZachMechanicsConfigurationESD moved closer to disk in CR0We first measured the distance of the ESD
from the disk in the test chamber (CR0).
We had to remove the retaining ring to have
  406   Fri Aug 11 09:22:21 2017 GabrieleMechanicsConfigurationESD moved closer to disk in CR0The plots below compare the SNR and peak
amplitude of all excited modes, in the new
and old configuration. The new confgiuration
  18   Thu May 26 02:51:27 2016 GabrieleElectronicsDesignESD designA preliminary design of the ESD board is
available on the DCC: D1600214
  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
  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
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