2017-07-26

Sweeping the space between ESD and sample

2017-07-26

I ran a sweep of the gap between the ESD and the sample, first from .5 mm to 1 mm. That sweep suggested that there is a significant jump in force across almost all of the modes at 1 mm. To confirm this I double checked the geometry and it appears that COMSOL is building everything as expected when changing the spacing parameter. Then I ran a finer sweep in .02 mm increments for the spacing between .9 and 1.1 mm. Once again it appears there is a large jump as the gap approaches 1 mm, but the behavior does not seem to be symmetric about that point, the force appears to diminish linearly as the gap increases beyond 1 mm. I will run a sweep of the ESD arm spacing along with the vertical gap to confirm that the jump occurs when the gap between the ESD and the sample is equivalent to the spacings between the ESD arms.

Attachment 1: Gap_near_one.jpg

378

Tue Jul 25 13:38:30 2017

Parametric Sweep of ESD gap

2017-07-25

I completed a short sweep of the gap between the drive and the sample, between .5 and 1 mm in .1 mm increments. It appears that a 1 mm distance is the ideal distance by approximately a factor of two. I will next sweep larger distances and see how the force profile behaves at greater distances.

377

Tue Jul 25 11:22:37 2017

S1600548 S1600550 S1600538

2017-07-25

11:12am in chamber (non standard order is not a typo!!)
- S1600548 in CR1
- S1600550 in CR2
- S1600538 in CR3
11:13am roughing pump on
11:22am turbo pump on
Excitations:
- Quiet time before excitation: 1185056320
  Excitation broadband: 1185056355
  Quiet time after excitation: 1185056380
- Quiet time before excitation: 1185057610
  Excitation broadband: 1185057645
  Quiet time after excitation: 1185057670
- Quiet time before excitation: 1185058900
  Excitation broadband: 1185058935
  Quiet time after excitation: 1185058960
- Quiet time before excitation: 1185060190
  Excitation broadband: 1185060226
  Quiet time after excitation: 1185060251
- Quiet time before excitation: 1185061481
  Excitation broadband: 1185061516
  Quiet time after excitation: 1185061541
- Quiet time before excitation: 1185062771
  Excitation broadband: 1185062806
  Quiet time after excitation: 1185062831
- Quiet time before excitation: 1185064061
  Excitation broadband: 1185064096
  Quiet time after excitation: 1185064121
- Quiet time before excitation: 1185065351
  Excitation broadband: 1185065386
  Quiet time after excitation: 1185065411

2017-07-26

4:05pm valve closed, pumps stopped, venting

376

Mon Jul 24 16:06:11 2017

S1600530 S1600532 S1600537 S1600539

2017-07-24

3:55pm installed in chamber
- S1600530 in CR1
- S1600532 in CR2
- S1600537 in CR3
- S1600539 in CR4
3:58pm roughing pump on
4:06pm turbo pump on
Excitations:
- Quiet time before excitation: 1184986754
  Excitation broadband: 1184986789
  Quiet time after excitation: 1184986814
- Quiet time before excitation: 1184988044
  Excitation broadband: 1184988079
  Quiet time after excitation: 1184988104
- Quiet time before excitation: 1184989334
  Excitation broadband: 1184989369
  Quiet time after excitation: 1184989394
- Quiet time before excitation: 1184990625
  Excitation broadband: 1184990660
  Quiet time after excitation: 1184990685
- Quiet time before excitation: 1184991915
  Excitation broadband: 1184991950
  Quiet time after excitation: 1184991975
- Quiet time before excitation: 1184993205
  Excitation broadband: 1184993240
  Quiet time after excitation: 1184993265
- Quiet time before excitation: 1184994495
  Excitation broadband: 1184994530
  Quiet time after excitation: 1184994555
- Quiet time before excitation: 1184995785
  Excitation broadband: 1184995820
  Quiet time after excitation: 1184995845

2017-07-25

11:00am valve closed, pumps stopped, venting

375

Mon Jul 24 09:13:45 2017

2017-07-24

I wrote a MATLAB script that is capable of sweeping parameters, the code is attached. The next step is to create nested loops so that I can sweep multiple parameters in a single run. I also should add a function in the script to eliminate the modes that cannot be measured by the experimental setup.
My first sweep was for the gap between electrodes and swept from 1 to 2 mm. In the plot the gap grows from steps 1 to 6 and the only obvious effect in the plot is a decrease in force from the highest mode. Intuitively it makes sense that a wider gap would decrease the force because the electric field is diminished by spreading out the electrodes.
I would like to add a parameter for the overlap of the electrodes, but this would require substantial redesigning of the COMSOL model due to the multilevel dependency on parameters.

Attachment 2: forcesweep.m

fpro = zeros(6, 27);
no = 1;
for count = 1:.2:2
    gap = strcat(num2str(count), ' [mm]')
    model = fst2(gap);
    forces;
    fpro(no, :)= product(:);
    no = no + 1;
end

374

Sat Jul 22 13:05:46 2017

S1600533 S1600535 S1600536 S1600547

2017-07-22

12:55pm in chamber
- S1600533 in CR1
- S1600535 in CR2
- S1600536 in CR3
- S1600547 in CR4
Added neutral densities
12:57pm roughing pump on
1:05pm turbo pump on
Excitations
- Quiet time before excitation: 1184803575
  Excitation broadband: 1184803611
  Quiet time after excitation: 1184803636
- Quiet time before excitation: 1184804866
  Excitation broadband: 1184804901
  Quiet time after excitation: 1184804926
- Quiet time before excitation: 1184806156
  Excitation broadband: 1184806191
  Quiet time after excitation: 1184806216
- Quiet time before excitation: 1184807446
  Excitation broadband: 1184807481
  Quiet time after excitation: 1184807506
- Quiet time before excitation: 1184808736
  Excitation broadband: 1184808771
  Quiet time after excitation: 1184808796
- Quiet time before excitation: 1184810027
  Excitation broadband: 1184810062
  Quiet time after excitation: 1184810087
- Quiet time before excitation: 1184811317
  Excitation broadband: 1184811352
  Quiet time after excitation: 1184811377
- Quiet time before excitation: 1184812607
  Excitation broadband: 1184812642
  Quiet time after excitation: 1184812667
More excitations
- Quiet time before excitation: 1184878758
  Excitation broadband: 1184878794
  Quiet time after excitation: 1184878819
- Quiet time before excitation: 1184880049
  Excitation broadband: 1184880084
  Quiet time after excitation: 1184880109
- Quiet time before excitation: 1184881339
  Excitation broadband: 1184881374
  Quiet time after excitation: 1184881399
- Quiet time before excitation: 1184882629
  Excitation broadband: 1184882664
  Quiet time after excitation: 1184882689
- Quiet time before excitation: 1184883919
  Excitation broadband: 1184883954
  Quiet time after excitation: 1184883979
- Quiet time before excitation: 1184885210
  Excitation broadband: 1184885245
  Quiet time after excitation: 1184885270
- Quiet time before excitation: 1184886500
  Excitation broadband: 1184886536
  Quiet time after excitation: 1184886561
- Quiet time before excitation: 1184887791
  Excitation broadband: 1184887826
  Quiet time after excitation: 1184887851

2017-07-24

3:28pm valve closed, venting

373

Fri Jul 21 14:55:02 2017

Shear and bulk losses in annealed tantala

I repeated the analysis for bulk and shear losses described in an early elog entry, with the same coating, but after annealing at 500C for 9 hours.

The COMSOL model is the same as before, so the dilution factors are the same, except that this time I could measure a few more modes at high frequency:

As in the previous analysis, I fitted four different models:
1) one single loss angle for both bulk and shear, constant in frequency
2) one single loss angle for both bulk and shear, linear in frequency
3) separate bulk and shear loss angles, constant
4) separate bulk and shear loss angles, linear in frequency

The data strongly favor the last model: two loss angles for shear and bulk, linearly dependent on frequency (Bayes factor -22.7 for the second best model, which is the frequency dependent single loss angle).

The results are below.

Single constant loss angle

$\phi = (3.95 \pm 0.08) \times 10^{-4} \mbox{ rad}$

Single loss angle, linearly dependent on frequency

$\phi = (3.69 \pm 0.17) \times 10^{-4} + \frac{f-1 kHz}{1 kHz} (4.6 \pm 0.3)\times 10^{-6} \mbox{ rad}$

Bulk and shear loss angles, constant

$\begin{array}{l} \phi_{shear} = (3.4 \pm 0.5) \times 10^{-4} \mbox{ rad} \\ \phi_{bulk} = (7.3 \pm 3.3) \times 10^{-4} \mbox{ rad} \\ \end{array}$

Bulk and shear loss angles, linearly dependent on frequency

$\begin{array}{l} \phi_{shear} = (3.58 \pm 0.15) \times 10^{-4} + \frac{f - 1 kHz}{1 kHz} (6.1 \pm 2.4) \times 10^{-6} \mbox{ rad} \\ \phi_{bulk} = (4.5 \pm 1.2) \times 10^{-4} + \frac{f - 1 kHz}{1 kHz} (-7 \pm 16) \times 10^{-6} \mbox{ rad} \\ \end{array}$

Attachment 7: postannealing_linear_bulk_shear.png

372

Fri Jul 21 08:42:09 2017

2017-07-21

8:30am, in chamber (CR4)
8:32am, roughing pump on
8:41am, turbo pump on
Excitations
- Quiet time before excitation: 1184697303
  Excitation broadband: 1184697338
  Quiet time after excitation: 1184697363
- Quiet time before excitation: 1184698593
  Excitation broadband: 1184698628
  Quiet time after excitation: 1184698653
- Quiet time before excitation: 1184699883
  Excitation broadband: 1184699918
  Quiet time after excitation: 1184699943
- Quiet time before excitation: 1184701173
  Excitation broadband: 1184701208
  Quiet time after excitation: 1184701233
- Quiet time before excitation: 1184702463
  Excitation broadband: 1184702499
  Quiet time after excitation: 1184702524
- Quiet time before excitation: 1184703754
  Excitation broadband: 1184703789
  Quiet time after excitation: 1184703814
- Quiet time before excitation: 1184705044
  Excitation broadband: 1184705079
  Quiet time after excitation: 1184705104
- Quiet time before excitation: 1184706334
  Excitation broadband: 1184706369
  Quiet time after excitation: 1184706394

2017-07-22

12:13pm, valve closed, pumps off

371

Thu Jul 20 11:37:01 2017

2017-07-20

I believe my MATLAB script successfully calculates the force distribution into each of the modes specified by the parameters. My previous error was caused by my neglecting the proportionality factor of $\frac{1}{2}\chi_e\epsilon_0$ . Now the force order of magnitude is on the order of 10³. I am currently unclear how to think about the units of the mode shapes from the disk_frequencies script, but I will pick it apart more carefully and try to figure that out. Then it will be a matter of converting units so that it matches with the N/m^3 from the COMSOL script and then comparing with real lab results. It seems to me that the error in force distribution should be inversely proportional to the number of modes calculated, in which case it would be useful to determine an appropriate number of modes to calculate.

Attachment 1: forces.m

par.a = 75e-3/2;    % radius [m]
par.h = 1.004e-3;   % thickness [m]
par.E = 73.2e9;     % Young's modulus [Pa]
par.nu = 0.155;     % Poisson's ratio
par.rho = 2202;     % density [kg/m^3]

%Calculate fundamental modes of the disk
[freqs, modes, shapes, x, y] = disk_frequencies(par, 10000, 1, 'shapes', 0.5e-3);

%Now we extract the force profile from the COMSOL model

... 27 more lines ...

370

Wed Jul 19 21:19:14 2017

Shear and bulk losses in tantala

To quantify which of the fit below is the most significant, I did a Bayesian analysis (thanks Rory for the help!).

In brief, I compute the Bayes factors for each of the models considered below. As always in any Bayesian analysis, I had to assume some prior distribution for the fit parameters. I used uniform distributions, between 0 and 20e-4 for the loss angles, and between -100e-6 and 100e-6 for the slope. I checked that the intervals I choose for the priors have only a small influence on the results.

The model that has the highest probability is the one that considers different bulk and shear frequency depent loss angles. The others have the following relative probabilities

One loss angle constant: 1/13e+13
One loss angle linear in frequency: 1/5.5
Bulk/shear angles constant: 1/48784
Bulk/shear angles linear in frequency: 1/1

So the constant loss angle models are excluded with large significance. The single frequency dependent loss angle is less probable that the bulk/shear frequency dependent model, but only by a factor of 5.5. According to the literature, this is considered a substantial evidence in favor of frequency dependent bulk/shear loss angles.

Quote:

Results

One loss angle - constant

$\phi = (6.99 \pm 0.05) \times 10^{-4} \mbox{ rad}$

One loss angle - linear in frequency

$\phi = (6.91 \pm 0.07) \times 10^{-4} +\frac{f-1 \mbox{ kHz}}{1 \mbox{ kHz}} \cdot (3.3 \pm 2.2) \times 10^{-6} \mbox{ rad}$

Bulk and shear - constant

$\begin{matrix} \phi_{shear} = (6.79 \pm 0.12) \times 10^{-4} \mbox{ rad} \\ \phi_{bulk} = (8.54 \pm 0.98) \times 10^{-4} \mbox{ rad} \end{matrix}$

Bulk and shear - linear in frequency

$\begin{matrix} \phi_{shear} = (6.9 \pm 0.4) \times 10^{-4} +\frac{f-1 \mbox{ kHz}}{1 \mbox{ kHz}} \cdot (9.9 \pm 7.4) \times 10^{-6} \mbox{ rad} \\ \phi_{bulk} = (6.4 \pm 3.7) \times 10^{-4} +\frac{f-1 \mbox{ kHz}}{1 \mbox{ kHz}} \cdot (-14 \pm 39) \times 10^{-6} \mbox{ rad} \end{matrix}$

369

Tue Jul 18 09:13:08 2017

Shear and bulk losses in tantala

S1600525 has been coated in Fort Collins with 480nm of pure tantala. I used the emasured loss angles (after deposition, before annealing) to estimate the shear and bulk loss angles.

Model

First, my COMSOL simulation shows that even if I don’t include the drum-like modes, I still have a significant scatter of shear/bulk energy ratio. The top panel shows indeed the ratio shear/bulk for all the modes I can measure, and the variation is quite large. So, contrary to my expectation, there is some room for fitting here. The bottom panel just shows the usual dilution factors.

Then I tried to fit the total losses in my sample (the substrate is negligible) using four different models:

1) one single loss angle for both bulk and shear, constant in frequency

2) one single loss angle for both bulk and shear, linear in frequency

3) separate bulk and shear loss angles, constant

4) separate bulk and shear loss angels, linear in frequency

Instead of using Gregg harry's technique (taking pairs of losses together), I simply fit the whole datasets with the assumptions above. I derived the 95% confidence intervals for all parameters. I also weighed each data point with the experimental uncertainty. I’m not sure yet how to compare the performance of the various models and decide which is the best one, since clearly the more parameters I plug into the model, the better the fit gets.

If I use two different loss angles, but constant, I get numbers similar to what Gregg presented at the last Amaldi conference (G1701225), but inverted in bulk and shear. I cross checked that I didn’t do any mistake. Instead, if I allow linear dependency on frequency of bulk and shear, I get a trend similar to the one in Gregg's slides.

My plan is to have this sample annealed today or tomorrow and measure it again before the end of the week.

Results

One loss angle - constant

$\phi = (6.99 \pm 0.05) \times 10^{-4} \mbox{ rad}$

One loss angle - linear in frequency

$\phi = (6.91 \pm 0.07) \times 10^{-4} +\frac{f-1 \mbox{ kHz}}{1 \mbox{ kHz}} \cdot (3.3 \pm 2.2) \times 10^{-6} \mbox{ rad}$

Bulk and shear - constant

$\begin{matrix} \phi_{shear} = (6.79 \pm 0.12) \times 10^{-4} \mbox{ rad} \\ \phi_{bulk} = (8.54 \pm 0.98) \times 10^{-4} \mbox{ rad} \end{matrix}$

Bulk and shear - linear in frequency

368

Fri Jul 14 16:43:24 2017

Force profile matlab script

2017-07-14

I have completed a rough, but functioning script that calculates the modal force profiles. The force values are still coming out incorrect (on the order of 10^14) but the script can take in my model as a .m file and return an array with a force value per mode. I am attaching both the .m file and the matlab script
I have done very little work with the numerical integration itself, based on the 2D numerical integration code I received I just appended a z component and left it at that so when I return from Livingston I will fix that component

Attachment 1: forces.m

par.a = 75e-3/2;    % radius [m]
par.h = 1.004e-3;   % thickness [m]
par.E = 73.2e9;     % Young's modulus [Pa]
par.nu = 0.155;     % Poisson's ratio
par.rho = 2202;     % density [kg/m^3]

%Calculate fundamental modes of the disk
[freqs, modes, shapes, x, y] = disk_frequencies(par, 10000, 1, 'shapes', 0.5e-3);

%Now we extract the force profile from the COMSOL model

... 41 more lines ...

Attachment 2: faster.m

function out = model
%
% faster.m
%
% Model exported on Jul 14 2017, 14:47 by COMSOL 5.2.1.262.

import com.comsol.model.*
import com.comsol.model.util.*

model = ModelUtil.create('Model');

... 403 more lines ...

367

Wed Jul 12 15:08:59 2017

Model of actuator and sample

2017-07-12

I am attaching the first fully functioning model of the actuator and sample. I cleared both meshes and solutions to make the file a reasonable size, but they can quickly be built/solved again.

Attachment 1: Force_Model.mph

366

Thu Jul 6 12:48:54 2017

Resolving the factor of two

2017-07-06

I resolved the factor of two from Griffiths' discussion of dipoles in non-uniform electric fields. The force on a dipole in a non-uniform field is $\textbf{F}=\textbf{F}_+ + \textbf{F}_-=q(\Delta \textbf{E})$ where $\Delta \textbf{E}$ is the difference in the field between the plus end and the minus end. Component wise, $\Delta E_x = (\nabla E_x) \cdot \textbf{d}$ where d is a unit vector. This holds for y and z, the whole thing can also be written as $\Delta \textbf{E} = (\textbf{d} \cdot \nabla) \textbf{E}$ . Since p=qd, we can write $\textbf{F} = (\textbf{p} \cdot \nabla) \textbf{E}$ .

Jackson derives it differently by deriving the electrostatic energy of a dielectric from the energy of a collection of charges in free space. He then derives the change in energy of a dielectric placed in a fixed source electric field to derive that the energy density w is given by $w = -\frac{1}{2} \textbf{P} \cdot \textbf{E}_0$ . This explicity explains the factor of two and is an interesting alternative explanation.

365

Thu Jul 6 12:08:35 2017

Checking physical parameters

2017-07-06

I compared the electric field and the polarization to make sure that those calculations made sense. Since $P = \epsilon_0 \chi_e E$ due to the linear dielectric, I plotted the electric field and the polarization divided by the proportionality constant and they match exactly.
This confirms both the constant value and the polarization distribution but gets me no closer to resolving the factor of two

364

Wed Jul 5 16:40:51 2017

Force disparity-improvement

2017-07-05

In order to improve my data I shrunk the region of the finer meshing slightly and made the mesh even smaller and then recalculated the force profiles. This time I tried sampling regions inside the disc rather than immediately at the surface. The attached graphs were sampled at the center of the disc. These two techniques vastly improved the data, now the profiles appear the same, but the magnitudes differ by a factor of 2 again. Previously this was due to an error in my calculation of the force, now I do not believe this to be the case. I will leave my work here for the purposes of my first report, it is an interesting result. I also restricted my data set to the finely meshed box which resolved the earlier data display issue.

363

Wed Jul 5 12:01:51 2017

Force plots-Correct plots, force issue

2017-07-05

I sorted out my mathematical lapse in logic and computed the correct force profiles in the perpendicular direction in both disks. The issue is that now the force profiles don't match up. The fact that there is a measured force distribution for the E^2 case outside the disk is only an artifact of the numerics because it is being calculated only from the electric field data which is defined outside the sample. It can be easily removed for final plots once the force distributions are matched by either redefining the cut plane or putting a data filter specifically on the E^2 plot. The jumps in the E^2 plot suggest that the meshing is still too large, I will try to fix this first, hopefully it will help resolve the difference.

362

Wed Jul 5 10:01:29 2017

S1600547 S1600548 S1600549 S1600550

2017-07-05

NOTE: at 9:40am switched off turbo pump in CR0 to avoid vibrations
NOTE: boxes are labeled as S1600546/547/548/549 but must be relabeled as S1600547/548/549/550
9:53am, in chamber
- S1600547 in CR1
- S1600548 in CR2
- S1600549 in CR3
- S1600550 in CR4
9:54am roughing pump on
10:02am turbo pump on
Excitations:
- Quiet time before excitation: 1183323620
  Excitation broadband: 1183323655
  Quiet time after excitation: 1183323680
- Quiet time before excitation: 1183330910
  Excitation broadband: 1183330945
  Quiet time after excitation: 1183330970
- Quiet time before excitation: 1183338200
  Excitation broadband: 1183338235
  Quiet time after excitation: 1183338260
- Quiet time before excitation: 1183345490
  Excitation broadband: 1183345525
  Quiet time after excitation: 1183345550
- Quiet time before excitation: 1183352780
  Excitation broadband: 1183352815
  Quiet time after excitation: 1183352840
- Quiet time before excitation: 1183360070
  Excitation broadband: 1183360105
  Quiet time after excitation: 1183360130
- Quiet time before excitation: 1183367360
  Excitation broadband: 1183367395
  Quiet time after excitation: 1183367420
- Quiet time before excitation: 1183374650
  Excitation broadband: 1183374685
  Quiet time after excitation: 1183374710

2017-07-06

3:45pm, valve closed, vented, pumps stopped

361

Fri Jun 30 16:27:56 2017

Double Checking Model

2017-06-30

In order to confirm the accuracy of my model I checked some easily computable quantities between what real values and what COMSOL produced. My expected electric field magnitude between the electrodes is 10⁶ V/m and COMSOL reads out 1.015*10⁶which is less than a 2% error. When I went to compute the electric field gradient however, I discovered that I had been calculating my derivatives wrong, I was calculating full derivatives when I needed partial derivatives. Due to some subtleties of the numerics involving curl calculations are the order of the variables, in order to calculate a partial I belive that I have to map the results of the electric field to Lagrange elements.

360

Fri Jun 30 11:02:18 2017

2017-06-30

I adjusted the plot parameters slightly so that it only showed the actual force profile on the sample in the direction perpendicular to the sample surface. Additionally I compared the two methods of computing the force, as $\vec{F} = -(\vec{P}\cdot \nabla)\vec{E}$ and as $\vec{F} =- \chi_e \epsilon_0 \nabla \vec{E}^2$ . The profile of the force in both instances appear equal, but they differ in magnitude by exactly a factor of 2, I plotted the force computed with the explicit polarization doubled and the force magnitudes matched exactly. I'm still not entirely sure where this factor of two could be coming from.

359

Thu Jun 29 16:40:41 2017

Accurate model and force profile

2017-06-29

I created a much more accurate model of the current ESD setup from the technical drawings. My resulting ESD has dimensions of 21.3x24.3x.1mm with 1 mm spacings and 17.5 mm long electrode arms. The sample has a diameter of 75 mm and thickness of 1mm, the ESD is 1mm below the sample in the current model. I still have to compare the technical drawings to confirm that is the actual distance in the current lab setup.
I was able to calculate the force profile on the disk from the ESD. COMSOL struggled to resolve the data with a small mesh size over the whole domain, so I created a region of extremely fine mesh around the ESD and the disk and then made the rest of the mesh size normal sized. Over the domain near the ESD my mesh size ranges from 2.5*10^-3 to .25 mm and over the rest of the domain it's automatically setup at the normal size.
The force on a single dipole is given as $F = (P \cdot \nabla)E$ , since fused silica is isotropic it's polarization is proportional to E so $F = \chi_e \epsilon_0 \nabla (E^2)$ . The electric suscepitibility of fused silica is 1.09, I plotted the profile of the force perpendicular to the plane of the disk and exported data files of the full vector quantity of the force for use with Matlab.

358

Thu Jun 29 13:15:01 2017

Alastair, Gabriele

Laser polishing

We laser polished S1600546, 547, 548, 549, 550 and 551

357

Wed Jun 28 15:50:15 2017

2017-06-28

We plan to leave S1600541 in vacuum for a long period, and measure the Q's periodically.

3:48pm, S1600541 installed in CR0
3:50pm, roughing pump on
4:35pm turbo pump on

356

Tue Jun 27 14:17:47 2017

Further plots and improving models

2017-06-27

I built a new model of the ESD to determine whether or not the spikes in the electric field at the corners was affecting the results enough that it had to be accounted for in further models. To create the model, I created a 2D profile of the arm used in my original model and filleted the corners at a radius of .05 mm, since the electrode model is .1 mm thick, this made completely rounded edges. In creating this model I caught an earlier mistake in the original one, I only set one half of the surface of the electrodes to have a potential or to ground, the "bottom" was left with no charge. I fixed this mistake and then compared the two models at a potential of 1000 V. For speed of computation I ran both models with a finer mesh size and then calculated the electric field at approximately the middle of the ESD, 1mm above the fourth electrode arm. For the rounded electrodes the field had a value of 84024 V/m and for the rectangular electrodes the field had a value of 80728 V/m, which is less than a 4% difference in field magnitude. Furthermore, the field shapes appear nearly indistinguishable; I am confident from this test that I can proceed modelling the arms of the ESD as rectangles.

Attachment 1: E_field_corner.png

Attachment 2: E_field_round.png

355

Tue Jun 27 09:20:16 2017

Alena

Annealing run (546-551) on 3" wafers - Crime 06/27/2017

Annealing

Started annealing run https://dcc.ligo.org/T1700293

Will be ready by June 28th afternoon

354

Sat Jun 24 12:59:27 2017

S1600541 S1600542 post annealing

2017-06-24

12:47pm in chamber
- S1600541 in CR1
- S1600542 in CR3
12:50pm roughing pump on
12:59pm turbo pump on
Excitations
- Quiet time before excitation: 1182524202
  Excitation broadband: 1182524237
  Quiet time after excitation: 1182524262
- Quiet time before excitation: 1182535092
  Excitation broadband: 1182535127
  Quiet time after excitation: 1182535152
- Quiet time before excitation: 1182545982
  Excitation broadband: 1182546017
  Quiet time after excitation: 1182546042
- Quiet time before excitation: 1182556872
  Excitation broadband: 1182556907
  Quiet time after excitation: 1182556932
- Quiet time before excitation: 1182567762
  Excitation broadband: 1182567797
  Quiet time after excitation: 1182567822
- Quiet time before excitation: 1182578652
  Excitation broadband: 1182578687
  Quiet time after excitation: 1182578712
- Quiet time before excitation: 1182589542
  Excitation broadband: 1182589577
  Quiet time after excitation: 1182589602
- Quiet time before excitation: 1182600432
  Excitation broadband: 1182600467
  Quiet time after excitation: 1182600492

2017-06-28

3:36pm, valve closed, vented, pumps stopped

353

Fri Jun 23 12:02:12 2017

2017-06-23

I created plots of the E field and potential from my rough model of the ESD. This model has 1mm electrode arm widths and spacings, the length of each arm is 16 mm, and the resulting total size is 38mm x 20 mm x 0.1 mm. One comb has ten arms while the other has nine to match the actual ESD currently in use in the lab.
I set the ten arm comb to a potential of 100 V and the other to ground. I then used physics controlled mesh with an extremely fine element size to computer the simulations. With mesh sizes larger than extra fine, there was clearly non-physical error in the electric field and potential graphs that appeared as inexplicable field lines, spikes, and coarseness in the plots.
To create readable plots of the potential I created a Cut Plane in the center of the ESD perpendicular to both the arms and the plane of the device. The plots are attached with a milimeter length scale. I created a filled contour plot of the potential that is very clean, I tried a couple of different options for the electric field because it is harder to represent well. I created a contour plot for the norm of the electric field as well as superimposing a streamline plot of the field lines over that. Everything behaves generally as expected though I do suspect the spikes in electric field at the edges of each electrode are due to the fact that they are sharp corners and not smooth edges.

Attachment 1: Potential.png

Attachment 2: E_w_Lines.png

Attachment 3: Mesh.png

352

Thu Jun 22 15:37:20 2017

2017-06-22

Created the geometry of the ESD by creating blocks and joining them with Unions. I then created a block to serve as the domain and added air to that region
This plot is a combination of a Surface plot of the potential and a Streamline plot of the electric field
I created another model of the ESD with more accurate measurements to the real thing and added the silica disc to the model

351

Thu Jun 22 13:16:37 2017

Beginning with COMSOL

2017-06-21

4:30 pm- Installed COMSOL, began modeling current ESD by creating parameters and the first arm of the comb

350

Wed Jun 21 17:04:20 2017

Alena

Annealing run (541-542) on 3" wafers - Crime 06/25/2017

Annealing

Started an annealing run https://dcc.ligo.org/LIGO-T1700271

Will be ready by Friday morning

349

Tue Jun 20 16:01:27 2017

Gabriele, Zach, Alastair

S1600541 S1600542 (laser polished)

2017-06-20

The two substrates were laser polished (CO2 power ~ 23 W)
3:50pm installed in chamber
- S1600541 in CR1
- S1600542 in CR3
3:52pm roughing pump on
4:00pm turbo pump on
Excitations
- Quiet time before excitation: 1182045787
  Excitation broadband: 1182045822
  Quiet time after excitation: 1182045887
- Quiet time before excitation: 1182056717
  Excitation broadband: 1182056752
  Quiet time after excitation: 1182056817
- Quiet time before excitation: 1182067648
  Excitation broadband: 1182067683
  Quiet time after excitation: 1182067748
- Quiet time before excitation: 1182078578
  Excitation broadband: 1182078613
  Quiet time after excitation: 1182078678
- Quiet time before excitation: 1182089509
  Excitation broadband: 1182089544
  Quiet time after excitation: 1182089609

2017-06-21

1:56pm, valve closed, pumps off

348

Fri Jun 16 15:56:55 2017

2017-06-16

3:25pm in chamber
- S1600541 in CR1
- S1600542 in CR3
3:45pm, roughing pump on
3:55pm turbo pump on
Exitations:
- Quiet time before excitation: 1181706587
  Excitation broadband: 1181706622
  Quiet time after excitation: 1181706687
- Quiet time before excitation: 1181717517
  Excitation broadband: 1181717552
  Quiet time after excitation: 1181717617
- Quiet time before excitation: 1181728447
  Excitation broadband: 1181728482
  Quiet time after excitation: 1181728547
- Quiet time before excitation: 1181739377
  Excitation broadband: 1181739412
  Quiet time after excitation: 1181739477
- Quiet time before excitation: 1181750307
  Excitation broadband: 1181750343
  Quiet time after excitation: 1181750408
- Quiet time before excitation: 1181761238
  Excitation broadband: 1181761273
  Quiet time after excitation: 1181761338
- Quiet time before excitation: 1181772168
  Excitation broadband: 1181772203
  Quiet time after excitation: 1181772268
- Quiet time before excitation: 1181783098
  Excitation broadband: 1181783133
  Quiet time after excitation: 1181783198
The turbo pump switched off, so the pressure was about 3e-2 Torr, all measurements are bad..

2017-06-19

8:48am, turbo pump on again
Excitations:
- Quiet time before excitation: 1181929822
  Excitation broadband: 1181929857
  Quiet time after excitation: 1181929922
- Quiet time before excitation: 1181937152
  Excitation broadband: 118193718
  Quiet time after excitation: 1181937252
2:28pm, valve closed, pumps off

2017-06-20

1:45pm vented

347

Thu Jun 15 11:20:13 2017

2017-06-15

11:13am in chamber
- S1600539 in CR1
- S1600540 in CR3
11:14am roughing pump on
11:23am turbo pump on
Excitations
- Quiet time before excitation: 1181596817
  Excitation broadband: 1181596852
  Quiet time after excitation: 1181596917
- Quiet time before excitation: 1181607747
  Excitation broadband: 1181607782
  Quiet time after excitation: 1181607847
- Quiet time before excitation: 1181618677
  Excitation broadband: 1181618712
  Quiet time after excitation: 1181618777

2017-06-16

3:17pm venting

346

Wed Jun 14 16:53:54 2017

2017-06-14

4:44pm in chamber
- S1600546 in CR1
4:47pm roughing pump on
4:55pm turbo pump on
Excitations
- Quiet time before excitation: 1181533731
  Excitation broadband: 1181533766
  Quiet time after excitation: 1181533831
- Quiet time before excitation: 1181544661
  Excitation broadband: 1181544696
  Quiet time after excitation: 1181544761
- Quiet time before excitation: 1181555591
  Excitation broadband: 1181555626
  Quiet time after excitation: 1181555691

2017-06-15

11:09am venting

345

Fri Jun 2 16:04:12 2017

2017-06-02

3:55pm in chamber:
- S1600525 in CR1
- S1600526 in CR3
3:56pm roughing pump on
4:04pm turbo pump on
Excitations:
- Quiet time before excitation: 1180561453
  Excitation broadband: 1180561488
  Quiet time after excitation: 1180561553
- Quiet time before excitation: 1180572383
  Excitation broadband: 1180572418
  Quiet time after excitation: 1180572483
- Quiet time before excitation: 1180583313
  Excitation broadband: 1180583348
  Quiet time after excitation: 1180583413
- Quiet time before excitation: 1180594243
  Excitation broadband: 1180594278
  Quiet time after excitation: 1180594343
- Quiet time before excitation: 1180605173
  Excitation broadband: 1180605208
  Quiet time after excitation: 1180605273
- Quiet time before excitation: 1180616103
  Excitation broadband: 1180616138
  Quiet time after excitation: 1180616203
- Quiet time before excitation: 1180627033
  Excitation broadband: 1180627068
  Quiet time after excitation: 1180627133
- Quiet time before excitation: 1180637963
  Excitation broadband: 1180637998
  Quiet time after excitation: 1180638063

2017-06-06

8:10am, pumps stopped, valve closed, chamber vented

2017-06-08

3:50pm, in chamber
- S1600525 in CR1
- S1600526 in CR3
3:50pm roughing pump on
4:00pm turbo pump on
Excitations:
- Quiet time before excitation: 1181012200
  Excitation broadband: 1181012235
  Quiet time after excitation: 1181012300
- Quiet time before excitation: 1181023130
  Excitation broadband: 1181023165
  Quiet time after excitation: 1181023230
- Quiet time before excitation: 1181034060
  Excitation broadband: 1181034095
  Quiet time after excitation: 1181034160
- Quiet time before excitation: 1181044990
  Excitation broadband: 1181045025
  Quiet time after excitation: 1181045090
More excitations
- Quiet time before excitation: 1181488352
  Excitation broadband: 1181488388
  Quiet time after excitation: 1181488453
- Quiet time before excitation: 1181499283
  Excitation broadband: 1181499318
  Quiet time after excitation: 1181499384
- Quiet time before excitation: 1181510214
  Excitation broadband: 1181510249
  Quiet time after excitation: 1181510314

2017-06-14

4:40pm, pumps stopped, valve closed, vented

344

Tue May 16 13:44:01 2017

Effect of meshing on dilution factor simulation

I ran a series of COMSOL simulations to compute the dilution factors of a coated disk with the dimensions we are currently using (75mm diameter, 1mm thick, 1um of coating).

The mesh is generated as follows:

a free triangular mesh with defined maximum element size is generated on the coating top surface
the triangular mesh is swept across the coating, generating a defined number of layers
the same mesh is swept through the substrate, generating a defined number of layers

The plots below shows the effect on the dilution factor convergence of the three parameters above. It turns out that the size of the surface trinagular mesh is the most relevant parameter, followed by hte number of layers in the coating. Instead, the number of layers in the substrate is not particularly relevant.

343

Mon May 15 13:19:12 2017

Q measured again after four weeks in vacuum

I measured again two of the substrates that have been sitting in the pumped-down vacuum chamber for about four weeks. The pressure now is below 1e-7 Torr. There is no significant difference between the two sets of measured Q values.

342

Thu Apr 20 09:10:25 2017

S1600542 S1600543 S1600544 S1600545

2017-04-20

9:09am in chamber
- S1600542 in CR1
- S1600543 in CR2
- S1600544 in CR3
- S1600545 in CR4
10:50am, roughing pump on
11:00am turbo pump on
Excitations:
- Quiet time before excitation: 1176767876
  Excitation broadband: 1176767911
  Quiet time after excitation: 1176767976
- Quiet time before excitation: 1176773406
  Excitation broadband: 1176773441
  Quiet time after excitation: 1176773506
- Quiet time before excitation: 1176778936
  Excitation broadband: 1176778971
  Quiet time after excitation: 1176779036
- Quiet time before excitation: 1176784466
  Excitation broadband: 1176784501
  Quiet time after excitation: 1176784566
- Quiet time before excitation: 1176789996
  Excitation broadband: 1176790031
  Quiet time after excitation: 1176790096
- Quiet time before excitation: 1176795526
  Excitation broadband: 1176795561
  Quiet time after excitation: 1176795626
- Quiet time before excitation: 1176801056
  Excitation broadband: 1176801091
  Quiet time after excitation: 1176801156
- Quiet time before excitation: 1176806586
  Excitation broadband: 1176806621
  Quiet time after excitation: 1176806686

2017-05-13

Excitations:
- Quiet time before excitation: 1178680521
  Excitation broadband: 1178680556
  Quiet time after excitation: 1178680621
- Quiet time before excitation: 1178691451
  Excitation broadband: 1178691486
  Quiet time after excitation: 1178691551
- Quiet time before excitation: 1178702381
  Excitation broadband: 1178702416
  Quiet time after excitation: 1178702481
- Quiet time before excitation: 1178713311
  Excitation broadband: 1178713346
  Quiet time after excitation: 1178713411
- Quiet time before excitation: 1178724241
  Excitation broadband: 1178724276
  Quiet time after excitation: 1178724341
- Quiet time before excitation: 1178735171
  Excitation broadband: 1178735206
  Quiet time after excitation: 1178735271
- Quiet time before excitation: 1178746101
  Excitation broadband: 1178746136
  Quiet time after excitation: 1178746201
- Quiet time before excitation: 1178757031
  Excitation broadband: 1178757066
  Quiet time after excitation: 1178757131

341

Fri Apr 14 13:49:17 2017

S1600538 S1600539 S1600540 S1600541

2017-04-14

1:45pm in chamber
- S1600538 in CR1
- S1600539 in CR2
- S1600540 in CR3
- S1600541 in CR4
1:48pm roughing pump on
2:00pm turbo pump on
Excitations
- Quiet time before excitation: 1176267253
  Excitation broadband: 1176267289
  Quiet time after excitation: 1176267354
- Quiet time before excitation: 1176281784
  Excitation broadband: 1176281819
  Quiet time after excitation: 1176281884
- Quiet time before excitation: 1176296314
  Excitation broadband: 1176296349
  Quiet time after excitation: 1176296414
- Quiet time before excitation: 1176310844
  Excitation broadband: 1176310879
  Quiet time after excitation: 1176310944
- Quiet time before excitation: 1176325374
  Excitation broadband: 1176325409
  Quiet time after excitation: 1176325474
- Quiet time before excitation: 1176339904
  Excitation broadband: 1176339939
  Quiet time after excitation: 1176340004
- Quiet time before excitation: 1176354434
  Excitation broadband: 1176354469
  Quiet time after excitation: 1176354534
- Quiet time before excitation: 1176368964
  Excitation broadband: 1176368999
  Quiet time after excitation: 1176369064

2017-04-20

8:58am valve closed, venting, pumps stopped

340

Tue Apr 11 14:07:48 2017

S1600533 S1600535 S1600536 S1600537

2017-04-11

2:02pm, in chamber
- S1600533 in CR1
- S1600535 in CR2
- S1600536 is CR3
- S1600537 in CR4
2:05pm roughing pump on
2:15pm, turbo pump on
Excitations:
- Quiet time before excitation: 1175994832
  Excitation broadband: 1175994867
  Quiet time after excitation: 1175994932
- Quiet time before excitation: 1176000362
  Excitation broadband: 1176000397
  Quiet time after excitation: 1176000462
- Quiet time before excitation: 1176005892
  Excitation broadband: 1176005928
  Quiet time after excitation: 1176005992
- Quiet time before excitation: 1176011422
  Excitation broadband: 1176011457
  Quiet time after excitation: 1176011522
- Quiet time before excitation: 1176016953
  Excitation broadband: 1176016988
  Quiet time after excitation: 1176017053
- Quiet time before excitation: 1176022483
  Excitation broadband: 1176022518
  Quiet time after excitation: 1176022583
- Quiet time before excitation: 1176028013
  Excitation broadband: 1176028048
  Quiet time after excitation: 1176028113
- Quiet time before excitation: 1176033543
  Excitation broadband: 1176033578
  Quiet time after excitation: 1176033643

2017-04-14

12:58pm, valve closed, pumps off

339

Mon Apr 10 16:22:12 2017

S1600529 S1600530 S1600531 S1600532

2017-04-10

4:10pm, in chamber:
- S1600529 in CR1
- S1600530 in CR2
- S1600531 in CR3
- S1600532 in CR4
4:14pm, roughing pump on
4:24pm, turbo pump on
Excitations:
- Quiet time before excitation: 1175916121
  Excitation broadband: 1175916156
  Quiet time after excitation: 1175916221
- Quiet time before excitation: 1175921651
  Excitation broadband: 1175921686
  Quiet time after excitation: 1175921751
- Quiet time before excitation: 1175927181
  Excitation broadband: 1175927216
  Quiet time after excitation: 1175927281
- Quiet time before excitation: 1175932711
  Excitation broadband: 1175932746
  Quiet time after excitation: 1175932811
- Quiet time before excitation: 1175938241
  Excitation broadband: 1175938276
  Quiet time after excitation: 1175938341
- Quiet time before excitation: 1175943771
  Excitation broadband: 1175943806
  Quiet time after excitation: 1175943871
- Quiet time before excitation: 1175949301
  Excitation broadband: 1175949336
  Quiet time after excitation: 1175949401
- Quiet time before excitation: 1175954831
  Excitation broadband: 1175954866
  Quiet time after excitation: 1175954931

2017-04-11

11:09 valve closed, pumps stopped

338

Fri Apr 7 16:19:03 2017

New 1103P laser installed

Optics

Daily Progress

This afternoon I installed the new Lumentum (former JDSU) HeNe laser, model 1103P in CR0.

Realigned everything.

I installed a sample in the chamber to reflect a beam back inot the QPD. Checking the QPD signals over a hour and more did not show any sign of excess noise or instability.

337

Fri Apr 7 14:12:52 2017

Eric, Gabriele

S1600525 S1600526 S1600527 S1600528

2017-04-07

2:12pm in chamber, pumps on
- S1600525 in CR1
- S1600526 in CR2
- S1600527 in CR3
- S1500528 in CR4
Excitations
- Quiet time before excitation: 1175653360
  Excitation broadband: 1175653395
  Quiet time after excitation: 1175653460
- Quiet time before excitation: 1175660690
  Excitation broadband: 1175660725
  Quiet time after excitation: 1175660790
- Quiet time before excitation: 1175668021
  Excitation broadband: 1175668056
  Quiet time after excitation: 1175668121
- Quiet time before excitation: 1175675351
  Excitation broadband: 1175675386
  Quiet time after excitation: 1175675451
- Quiet time before excitation: 1175682681
  Excitation broadband: 1175682717
  Quiet time after excitation: 1175682782
- Quiet time before excitation: 1175690012
  Excitation broadband: 1175690047
  Quiet time after excitation: 1175690112
- Quiet time before excitation: 1175697342
  Excitation broadband: 1175697377
  Quiet time after excitation: 1175697442
- Quiet time before excitation: 1175704672
  Excitation broadband: 1175704707
  Quiet time after excitation: 1175704772

2017-04-10

11:19am, valve closed, pumps off

336

Thu Mar 30 15:23:44 2017

Optics

Swapped HeNe laser in CR0

The JDSU HeNe laser 1103P that I was using is dead. I swapped it with a JDSU 1125P borrowed from the 40m.

335

Thu Mar 30 13:33:13 2017

2017-03-30

1:23pm, in chamber CR2
1:25pm, roughing pump started, clamps on
1:34pm turbo pump on
Excitations:
- Quiet time before excitation: 1174958541
  Excitation broadband: 1174958576
  Quiet time after excitation: 1174958641
- Quiet time before excitation: 1174960471
  Excitation broadband: 1174960506
  Quiet time after excitation: 1174960571
- Quiet time before excitation: 1174962401
  Excitation broadband: 1174962436
  Quiet time after excitation: 1174962501
- Quiet time before excitation: 1174964331
  Excitation broadband: 1174964366
  Quiet time after excitation: 1174964431
- Quiet time before excitation: 1174966261
  Excitation broadband: 1174966296
  Quiet time after excitation: 1174966361
- Quiet time before excitation: 1174968191
  Excitation broadband: 1174968226
  Quiet time after excitation: 1174968291
- Quiet time before excitation: 1174970122
  Excitation broadband: 1174970157
  Quiet time after excitation: 1174970222
- Quiet time before excitation: 1174972053
  Excitation broadband: 1174972088
  Quiet time after excitation: 1174972153

334

Wed Mar 29 11:57:09 2017

2017-03-29

11:47am, in chamber CR0, balanced
11:48am roughing pump on
12:00pm, turbo pump on
Excitations:
- Quiet time before excitation: 1174976553
  Excitation broadband: 1174976585
  Quiet time after excitation: 1174976607
- Quiet time before excitation: 1174977837
  Excitation broadband: 1174977869
  Quiet time after excitation: 1174977891
- Quiet time before excitation: 1174979121
  Excitation broadband: 1174979153
  Quiet time after excitation: 1174979175
- Quiet time before excitation: 1174980405
  Excitation broadband: 1174980437
  Quiet time after excitation: 1174980459
- Quiet time before excitation: 1174981689
  Excitation broadband: 1174981721
  Quiet time after excitation: 1174981743
- Quiet time before excitation: 1174982973
  Excitation broadband: 1174983006
  Quiet time after excitation: 1174983028
- Quiet time before excitation: 1174984258
  Excitation broadband: 1174984291
  Quiet time after excitation: 1174984313
- Quiet time before excitation: 1174985543
  Excitation broadband: 1174985575
  Quiet time after excitation: 1174985597

333

Wed Mar 22 12:47:40 2017