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 Coating Ring-down Measurement Lab elog, Page 5 of 18 Not logged in
ID Date Author Type Category Subject
160   Fri Nov 4 16:16:23 2016 AlenaGeneralGeneralAnnealing run

# Annealing run (460-465) on 3" wafers - Crime 11/04/2016 https://dcc.ligo.org/T1600513-x0

174   Thu Nov 10 16:07:13 2016 Alena, CalumGeneralGeneralAnnealing run

# Annealing run (466-471) on 3" wafers - Crime 11/10/2016

https://dcc.ligo.org/LIGO-T1600524

184   Mon Nov 14 08:54:49 2016 Alena, CalumGeneralGeneralAnnealing run

# Annealing run (472-477) on 3" wafers - Crime 11/11/2016 https://dcc.ligo.org/T1600527

196   Thu Nov 17 12:08:28 2016 GabrieleGeneralGeneralRemote control of air filters and roughing pump

I installed a network controlled power strip. The two air filters and the roughing pump are connected to this power strip and can be controlled remotely.

I added new buttons to the main MEDM screen to control them remotely.

198   Thu Nov 17 17:59:44 2016 Gabriele, AlastairGeneralGeneralCO2 laser polishing tests

We improved the control software of the laser polishing system: now the rotation speed is large when the laser is missing the disk because of the flats.

We used S1600479 as a test. This substrate was marked as damaged and had a clear chip. It went thoruhg two different polishing runs

• CO2 power ~19.5 W, speed 0.5 mm/s
• CO2 power ~18.5 W, speed 0.25 mm/s

The second run was probably too slow, and we can see some kind of traces left on the main surface close to the edges

We then laser polished a good subtrate (S1600439) which was already measured before (137) and after annealing (144), with good Q values. This is a substrate from the first batch we received from Mark Optics. The polishing was done at ~ 18W and 0.5 mm/s.

Some pictures below:

204   Mon Nov 21 11:46:57 2016 GabrieleGeneralGeneralMicroscope inspection of 439 and 487

## S1600439

This is the sample that was CO2 polished (198) and measured after polishing (197, 199). Unfortunately it got damaged during annealing:

I looked at the edge under the microscope. The first image is taken with light from above, and it shows a bit of residual defects in the center of the edge:

The images below are taken with light from below (which seems always the best choice) and they show some residual defects on the edge. Also, there is some "stuff" on the borders, like some fibers of some contamination. The first image is taken in correspondence of the damage, which is barely visible on the left edge. No clean problem is visible here.

## S1600487

This is a sample as received from Mark Optics. I will measure its Q values, laser polish it, measure again and then anneal it. Here are some images of the edges for future reference. The last one in particular shows the transition from the round part to the flats. The surface quality is clearly different.

205   Mon Nov 21 16:21:12 2016 Gabriele, AlastairGeneralGeneralLaser polishing of S1600487

The sample has been laser polished this afternoon, 0.5mm/s, average power 23 W.

We moved the lens that focuses the beam about one inch toward the sample, to make the beam slightly larger.

210   Wed Nov 23 14:16:59 2016 AlenaGeneralGeneralMicroscope inspection

Microscope inspection of samples:

S1600487  https://dcc.ligo.org/S1600487-v7

S1600438 https://dcc.ligo.org/S1600438

213   Mon Nov 28 16:02:16 2016 GabrieleGeneralGeneralExpected frequencies for the MIT samples
 Disk 3 x 1"/0.1mm 4 x 1"/0.1mm 4 x 1"/0.125" 306 319 322 243 306 319 324 319 464 480 487 447 703 739 751 679 703 743 751 679 1082 1140 1163 1101 1082 1140 1163 1101 1225 1288 1306 1211 1225 1288 1314 1283 1869 1941 1985 1750 1869 1941 1985 1904 1883 2003 2011 1904 1883 2003 2032 2017 2034 2155 2203 2065 2633 2731 2783 2759 2633 2745 2783 2784 2843 2986 3029 2877 2843 3006 3029 2877 3176 3325 3394 3307 3176 3325 3394 3307 3515 3645 3694 3629 3515 3645 3694 3630 3953 4152 4197 3673 3953 4152 4216 4001 4491 4655 4695 4560 4491 4655 4717 4673 4514 4697 4719 4739 4514 4697 4828 5132 4660 4814 4896 5301 5205 5463 5538 5302 5205 5463 5538 5350 5628 5793 5854 5849 5628 5795 5854 5849 5970 6208 6290 6088
220   Thu Dec 1 11:59:21 2016 Gabriele, AlastairGeneralGeneralLaser polishing

Today we laser polished S1600484, S1600485 and S1600486.

223   Fri Dec 2 14:05:47 2016 GabrieleGeneralGeneralMIT bare disk losses reproduced with edge and surface losses

The measured losses of the MIT bare disk show a remarkable split into families. The plot belo shows the measured total loss angles (error bars comes from dispersion of multiple measurements)

Using a COMSOL model, and tuning some parameters (E = 73.2 GPa, nu = 0.164, rho = 2202 kg/m^3, thickness = 0.511 mm) I can roughly reproduce the measured mode frequencies, within some tens of Hz:

There is still some splitting into families, so my guess is that the Poisson ratio is not quite right. But this is good enough for now. From this simulation, I can extract the various energies (bulk and shear) in different domains. In particular I'm focusing on the edge and surface energies. The following plot shows the ratio of shear/bulk edge energies over the total energy, as an example.

Now I used the edge shear energy ratio and the surface bulk energy ratio, and that's enough to reproduce the distribution of the measured loss angles:

The measured losses are well described by the following equation:

loss = 4.8e-6 * E_surface_bulk / E_tot + 1.2e-3 * E_edge_shear

The energy ratios here are not dimensionless, since they are the result of a surface integral over a volume integral. So to extract the real loss angles of the surface/edge defects we have to estimate the thickness of the surface/edge lossy area.

Attachment 4: losses_fit.png
226   Mon Dec 5 16:35:05 2016 GabrieleElectronicsGeneralHigh voltage relais

We want to be able to drive any combination of the four samples in the new setup, by using only one HV amplifier.

So I designed and built a remotely controlled relay box: one HV input and four HV outputs, controlled by four relais. The relais can be switched using a logic signal coming from DAC channels.

The system is finished, tested and working. Details in D1600456

242   Tue Dec 13 11:42:52 2016 GabrieleGeneralGeneralSteve Penn's model of loss angle

The plot below shows the best loss angle we expect foer our samples, based on Steve Penn's model of surface and volume losses (Phys. Lett. A 352, 3). That paper contains data only for Suprasil 2 and Suprasil 312, so it might be a bit wrong for our Corning 7980. The two experimental data sets are for samples that have been laser polished.

243   Thu Dec 15 11:58:55 2016 GabrieleGeneralGeneralEffect of clip fingerprints on dilution factor

The disks coated at Montreal are hold with three small clips. Therefore there are three small regions close to the edge that are not coated. See the picture below to see one of the samples with the clips.

To check the effect of the clip fingerprints on the dilution factor, I set up a COMSOL simulation. For simplicity, I started with only two small clips as shown below:

The result is that they have a very small effect. The first plot below compares the dilution factor (energy in the coating over total energy) with and without the fingerprints:

Another way to look at it is given below: the plot shows the percentage difference in the computed dilution factor. It's always smaller than 1%, so completely neglegible. In conclusion: we don't need to model the clips.

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

336   Thu Mar 30 15:23:44 2017 GabrieleOpticsGeneralSwapped 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.

337   Fri Apr 7 14:12:52 2017 Eric, GabrieleGeneralGeneralS1600525 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
Quiet time after excitation: 1175653460

• Quiet time before excitation: 1175660690
Quiet time after excitation: 1175660790

• Quiet time before excitation: 1175668021
Quiet time after excitation: 1175668121

• Quiet time before excitation: 1175675351
Quiet time after excitation: 1175675451

• Quiet time before excitation: 1175682681
Quiet time after excitation: 1175682782

• Quiet time before excitation: 1175690012
Quiet time after excitation: 1175690112

• Quiet time before excitation: 1175697342
Quiet time after excitation: 1175697442

## 2017-04-10

• 11:19am, valve closed, pumps off
344   Tue May 16 13:44:01 2017 GabrieleGeneralGeneralEffect 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:

1. a free triangular mesh with defined maximum element size is generated on the coating top surface
2. the triangular mesh is swept across the coating, generating a defined number of layers
3. 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.

358   Thu Jun 29 13:15:01 2017 Alastair, GabrieleGeneralGeneralLaser polishing

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

467   Tue Feb 27 14:39:21 2018 GabrieleGeneralGeneralCO2 polishing

Polished S1600619 S1600620 S1600621 S1600622

471   Thu Mar 1 13:20:33 2018 GabrieleGeneralGeneralCO2 polishing

CO2 polishing:

• S1600584
• S1600587
• S1600588: laser tripped near the end, restarted for a second round
• S1600591
• S1600592
472   Thu Mar 1 16:25:13 2018 GabrieleGeneralGeneralAging tests

Here's a ongoing summary of the substrate aging tests.

### S1600619

Mark Optics with polished edges and CO2 polished, stored in the CR0 vacuum chamber.

2018/03/01 470 LIGO-S1600619-v5
2018/03/03   LIGO-S1600619-v6
2018/03/09   LIGO-S1600619-v7
2018/03/15   LIGO-S1600619-v8
2018/03/24   LIGO-S1600619-v9

### S1600623

Mark Optics with polished edges, stored in standard wafer container in the dessicator cabinet

2018/03/01 469 LIGO-S1600623-v4
2018/03/08 480 LIGO-S1600623-v5
2018/03/16 488 LIGO-S1600623-v6

### S1600624

Mark Optics with polished edges, stored in standard wafer container in vacuum sealed envelope with dessicant

2018/03/01 469 LIGO-S1600624-v4
2018/03/08 480 LIGO-S1600624-v5
2018/03/16 488 LIGO-S1600624-v6

### S1600620

Mark Optics with polished edges and CO2 polished, stored in standard wafer container in the dessicator cabinet

2018/03/03 473

LIGO-S1600620-v5

2018/03/08 480 LIGO-S1600620-v6
2018/03/16 488 LIGO-S1600620-v7

### S1600621

Mark Optics with polished edges, stored in standard wafer container in vacuum sealed envelope with dessicant

2018/03/03 473 LIGO-S1600621-v5
2018/03/08 480 LIGO-S1600621-v6
2018/03/16 488 LIGO-S1600621-v7

Attachment 1: S1600619_history.png
Attachment 2: S1600623_history.png
Attachment 3: S1600624_history.png
Attachment 4: S1600620_history.png
Attachment 5: S1600621_history.png
Attachment 6: S1600619_history.png
Attachment 7: S1600623_history.png
Attachment 8: S1600624_history.png
Attachment 9: S1600620_history.png
Attachment 10: S1600621_history.png
Attachment 11: S1600619_history.png
Attachment 12: evolution.png
489   Sat Mar 24 17:03:57 2018 GabrieleGeneralGeneralAnnealing run

Started annealing of S1600577 S1600580 S1600582 S1600585 at 5pm

ramp up to 600C at 100C/h

hold at 600C for 10 h

ramp down at 100C/h

491   Sun Mar 25 17:10:04 2018 GabrieleGeneralGeneralAnnealing run

Started annealing of S1600579 S1600581 S1600583 S1600586 at 5:00pm

• ramp up to 300 C at 100 C/hour
• hold at 300 C for 5 hours
• ramp down at 100 C/hour
494   Mon Mar 26 16:10:03 2018 GabrieleGeneralGeneralAnnealing run

Started annealing of S1600579 S1600581 S1600583 S1600586 at 5:00pm

• ramp up to 400 C at 100 C/hour
• hold at 400 C for 5 hours
• ramp down at 100 C/hour
496   Tue Mar 27 11:41:06 2018 GabrieleGeneralGeneralAnnealing run

At 11:35am, started annealing of ten fused silica wafers (50.8mm / 0.1 mm) [S1800611 S1800612 S1800613 S1800614 S1800615 S1800616 S1800617 S1800618 S1800619 S1800620]

• ramp up to 900 C at 100 C/h
• hold for 9 h
• ramp down at 100 C/h

Attachment 1: IMG_4259.PNG
499   Wed Mar 28 15:32:07 2018 GabrieleGeneralGeneralAnnealing run

Started annealing of S1600579 S1600581 S1600583 S1600586 at 3:25pm

• ramp up to 500 C at 100 C/hour
• hold at 500 C for 10 hours
• ramp down at 100 C/hour
502   Thu Mar 29 16:15:08 2018 GabrieleGeneralGeneralAnnealing run

Samples S1600519 S1600522 S1600565 S1600566 S1600567 S1600568 S1600569

• ramp up to 500C at 100C/h
• hold at 500C for 10h
• ramp down at 100C/h
506   Sat Mar 31 09:58:56 2018 GabrieleGeneralGeneralAnnealing run

Started annealing of S1600579 S1600581 S1600583 S1600586 at 7:00pm 03/30

• ramp up to 600 C at 100 C/hour
• hold at 600 C for 10 hours
• ramp down at 100 C/hour
508   Sun Apr 1 10:11:22 2018 GabrieleGeneralGeneralAnnealing on blanks

Started annealing of blank disks: S1600541 S1600542 S1600545 S1600546 S1600551 S1600552 S1600554 S1600555

900C for 9 hours, starting at 10:30am

542   Fri Jun 22 10:53:06 2018 AlenaGeneralGeneralLaser failure

One of the HeNe lasers died (the one for measuring slots CR2 and CR4). It had no outgoing light when I came in this morning. I connected the laser to another identical power supply. The laser started going on and of and the power supply was making some sparkling noise. I swapped the laser with the test chamber (CR0). No re alignment was required for measurement slots CR1 and CR3. A very slight alignment was done for measuring slots CR2 and CR4 after the laser from the test chamber was installed. So temporary we do not have a setup to measure 2" samples easily. Attaching pictures of the broken lasers label

Attachment 1: 20180622_112134.jpg
Attachment 2: 20180622_112138.jpg
551   Wed Jul 25 11:23:44 2018 AlenaGeneralGeneralCR14 re-alignement

Aligned CR14 chamber back to 3" disks.

Attachment 1: 20180725_111415.jpg
554   Thu Jul 26 15:33:00 2018 AlenaGeneralGeneralNew laser instaled for the old chanber cr0

Installed a new HeNe laser for the old chamber cr0. No major alignement was required. The laser mount restored the alinement. Will run a test measurement now.

Attachment 1: 20180726_152508.jpg
Attachment 2: 20180726_152521.jpg
Attachment 3: 20180726_152530.jpg
Attachment 4: 20180726_154138.jpg
605   Fri Dec 21 11:21:03 2018 GabrieleGeneralGeneralS1600661 S1600662 S1600663 S1600664

## 2018-12-21

• in chamber
• S1600661 in CR1
• S1600662 in CR2
• S1600663 in CR3
• S1600664 in CR4
• 11:20am roughing pump on
• 11:30pm turbo pump on
689   Mon May 13 18:37:47 2019 aaronCleanGeneralClean room gear

Mon May 13 18:37:37 2019

Entered CRIME lab to borrow 4x hair nets and face masks. Can you please advise on what I should order for clean lab equipment? There are more options on techmart than I anticipated. We're in the process of increasing the cleanliness of the SiQ experiment.

696   Mon May 20 10:35:45 2019 aaronCleanGeneralClean room gear

Aaron,

There is a buy list of approved clean room supplies posted here https://dcc.ligo.org/LIGO-E1300399. This list is used by designated people to keep clean rooms supplies stock at each site including LIGO labs in Downs, 40m and the CRIME lab. Not sure what lab you are working in and what regulations you have there. Typically we study the list of the approved supplies, figure out what budget can be used for supplies for a particular experiment. Depending on what your project is, you may be able to just take what you need from the existing LIGO stock (I believe there is one for Downs and one for Bridge and 40m) or work with Liz, Bob or Chub on ordering it for your via approved channels.

 Quote: Mon May 13 18:37:37 2019 Entered CRIME lab to borrow 4x hair nets and face masks. Can you please advise on what I should order for clean lab equipment? There are more options on techmart than I anticipated. We're in the process of increasing the cleanliness of the SiQ experiment.

130   Tue Sep 27 15:10:59 2016 GabrieleGeneralMeasurementsRing-down of etched disk

Quiet (roughing pump off, lights off): 60 seconds from
PDT: 2016-09-27 15:05:30.805667 PDT
UTC: 2016-09-27 22:05:30.805667 UTC
GPS: 1159049147.805667
Follows excitation and ring-down with QPD autocentering (10 seconds interval). Centering is good starting 215 seconds after the time above.

There is a drift in X, corrected by the picomotor.

The spectrum of both QPD normalized signals looks quite bad. Maybe there's some scattered light issue.

134   Tue Oct 18 16:29:37 2016 GabrieleGeneralMeasurementsS1600433

# S1600433, annealing run 10/10/2016

## Installation

• Installed in the measurement system, chamber closed
• pump down started at 4:27pm LT
• turbo pump started at 4:38pm
• manually recentered the QPD at 4:39pm
• HV amplifer turned on at 4:41pm.

NOTE: initally I opened the roughing pump valve just a bit, to avoid shaking the disk too much. The reflected beam was moving quite a lot, but after the pressure went below roughly 1/3 atm there was no visible motion anymore and I opened up the valve completely.

Attached a trend of the QPD signals during the pump down. The time of incresed noise was at the beginning of the pump down.

## Measurements

2016-10-18

At 8:10pm, used the autocenter.py script to fine center the QPD. Cleaned the script log and started it again after the excitation.

Used the GUI to excite (amplitude 2000 V, duration 20s) and measure the ring downs at about 8:18pm. Results saved in ~/Measurements/S16004123/2016_10_18/ringdown_8pm_*

Clean reference time: 1160882205 + 30 s
Start of ringdown: 1160882395

The automated procedure did not identify many modes, I'll look at the result offline tomorrow.

Ringdown analyzed offline using the attached MATLAB script (ringdown_rawdata_2016_10_18.m). Some plots with the results:

The following plot shows the Q values, all quite low:

% Freq        Q
1111.8        3.4136e+06
2223.5        3.4789e+06
2550.2        1.9117e+06
2592.8        5.2546e+05
4442.2        1.3452e+06
6778.0        1.1197e+06
6789.2        5.4743e+06
6858.5        7.3921e+05
9548.2        7.9478e+05
10233.4       3.3426e+06
14209.2       3.6032e+06
16132.8       3.1556e+06
21414.5       4.9099e+06
27209.0       3.0791e+06
29136.6       5.4256e+06​

2016-10-19

• Stopped autocentering at 7:45am
• Excitation at 7:50am, ampltiude 1500 V, duration 30 s
• Autocentering on right after the excitation
• Measurement running, results saved in ~/Measurements/S16004123/2016_10_19/ringdown_8am_*

Ringdown analyzed offline using the attached MATLAB script (ringdown_rawdata_2016_10_19.m). Some plots with the results:

The following plot shows the Q values, all quite low:

% Freq        Q
1111.8        3.4159e+06
2550.2        1.9062e+06
2592.9        5.7773e+05
4442.3        1.3729e+06
6778.1        1.1435e+06
6789.5        5.8159e+06
6858.7        7.5672e+05
9548.4        8.9519e+05
10233.6       1.4926e+06
12744.3       7.9721e+05
14209.5       3.7492e+06
16123.8       1.0493e+06
16133.1       3.7737e+06
18686.6       1.7828e+06
21414.9       4.6938e+06
27209.6       3.5298e+06
29137.3       5.5508e+06
32020.0       1.8031e+06

2016-10-19

• Excitation at 11:04am, ampltiude 2000 V, duration 30 s
• Autocentering on during and after the excitation
• Measurement running, results saved in ~/Measurements/S16004123/2016_10_19b/ringdown_11am_*
• At 11:42am stopped the turbo pump

Ringdown analyzed offline using the attached MATLAB script (ringdown_rawdata_2016_10_19b.m). Some plots with the results:

The following plot shows the Q values, all quite low. Error bars are 95% confidence level from the fit.

% Freq        Q                 Qlow (C.I. 95%)   Qhi (C.I. 95%)
1111.7        3.4733e+06        3.4663e+06        3.4804e+06
2550.2        1.9189e+06        1.9141e+06        1.9238e+06
4442.2        1.3786e+06        1.3780e+06        1.3791e+06
4513.2        2.1947e+05        2.1809e+05        2.2087e+05
6778.1        1.1472e+06        1.1464e+06        1.1480e+06
6789.4        5.4143e+06        5.4015e+06        5.4272e+06
6858.7        7.9172e+05        7.8822e+05        7.9525e+05
9548.6        8.9155e+05        8.9070e+05        8.9240e+05
10233.8       1.4482e+06        1.4315e+06        1.4653e+06
12744.6       7.9081e+05        7.8886e+05        7.9276e+05
14209.6       3.7604e+06        3.7566e+06        3.7643e+06
16124.0       1.0353e+06        1.0331e+06        1.0374e+06
16133.3       3.8920e+06        3.8822e+06        3.9019e+06
16369.5       6.7332e+05        6.4937e+05        6.9910e+05
18687.0       2.0033e+06        1.9663e+06        2.0417e+06
20301.5       3.5757e+05        3.4389e+05        3.7239e+05
20366.0       5.7647e+05        5.6413e+05        5.8936e+05
23792.6       2.8356e+05        2.7808e+05        2.8927e+05
24798.0       4.9861e+05        4.9135e+05        5.0610e+05
27209.9       3.5452e+06        3.5176e+06        3.5732e+06
28945.0       1.3041e+06        1.2593e+06        1.3522e+06
29053.6       9.7020e+05        9.4791e+05        9.9356e+05
29137.7       5.4244e+06        5.3788e+06        5.4708e+06
31134.5       5.7329e+05        5.5971e+05        5.8754e+05
32019.6       1.9805e+06        1.9167e+06        2.0487e+06
Attachment 15: ringdown_rawdata_2016_10_18.m
%% Parameters
prefix = '2016_10_18';  % name of the folder where result will be saved
gps0 = 1160882205;      % GPS time of clean data before excitation
gps1 = 1160882395;      % GPS time right after excitation
dt = 30;                % how much data to be used to search peaks

minsnr = 6;             % minimum peak SNR
minfr = 1000;           % minimum peak frequency
Dt = 3600;              % total amount of time for the ringdown measurement


... 273 more lines ...
Attachment 16: ringdown_rawdata_2016_10_19.m
%% Parameters
prefix = '2016_10_19';  % name of the folder where result will be saved
gps0 = 1160923727;      % GPS time of clean data before excitation
gps1 = 1160923832;      % GPS time right after excitation
dt = 30;                % how much data to be used to search peaks

minsnr = 2;             % minimum peak SNR
minfr = 1000;           % minimum peak frequency
Dt = 3600;              % total amount of time for the ringdown measurement


... 275 more lines ...
Attachment 17: ringdown_rawdata_2016_10_19b.m
%% Parameters
prefix = '2016_10_19b';  % name of the folder where result will be saved
gps0 = 1160935440;      % GPS time of clean data before excitation
gps1 = 1160935526;      % GPS time right after excitation
dt = 30;                % how much data to be used to search peaks

minsnr = 5;             % minimum peak SNR
minfr = 1000;           % minimum peak frequency
Dt = 3600;              % total amount of time for the ringdown measurement


... 276 more lines ...
135   Tue Oct 18 16:52:16 2016 GabrieleGeneralMeasurementsSample inspections from annealing run 10/10/2016

LIGO-T1600466

• S1600432 shows some residual on face, close to the edge, probably from first contact
• S1600433 looks ok
• S1600434 shows a small residual on the face, the edge, probably from first contact, and a back spot, probably a residual of the contamination
• S1600435 shows a large halo on the face, like what you get when solvents dry on the surface leaving some traces
• S1600436 has some red residual on the edge, likely first contact
• S1600437 the surface looks ok but the edge has a clear reddish color
136   Wed Oct 19 13:35:23 2016 GabrieleGeneralMeasurementsS1600438

# S1600438, not annealed, as received from Mark Optics

## Installation

• Turbo pump switched off at 11:42am (2016-10-19)
• Turbo pumpo stopped (finally) at 1:11pm
• Chamber vented and opened at 1:13pm
• Sample installed and balanced at 1:18pm
• Chamber closed, roughing pump on at 1:20pm, turbo pump on at 1:35pm
• At 2:40pm pressure is about 2e-6 Torr
• Excited at 2:54pm, results are being saved in ~/Measurements/S1600438/2016_10_19/ringdown_3pm_*
• Roughing pump off at 3:57pm, turbo pump switched off
• at 4:27pm the pump spins at 120 Hz, opening the venting valve slowly, the turbo pump went down to 0 Hz in a couple of minutes
• at 4:35pm the sample was removed
Clean data: 1160949234 + 30s
Right after excitation: 1160949284 + 30s

Data have been analyzed with the attached MATLAB script ringdown_rawdata_2016_10_19.m

Results are shown below:

% Freq        Q                 Qlow (C.I. 95%)   Qhi (C.I. 95%)
1114.5        8.6842e+06        8.6163e+06        8.7530e+06
2600.0        1.5373e+06        1.5354e+06        1.5392e+06
4454.9        4.4458e+06        4.4439e+06        4.4476e+06
4526.4        3.1306e+05        3.1197e+05        3.1416e+05
6797.6        3.5778e+06        3.5758e+06        3.5799e+06
6809.8        9.1530e+06        9.1447e+06        9.1614e+06
6878.6        1.3829e+06        1.3784e+06        1.3873e+06
9576.6        3.0186e+06        3.0135e+06        3.0237e+06
10264.5       8.1674e+06        8.1534e+06        8.1815e+06
12782.6       2.5469e+06        2.5399e+06        2.5539e+06
14251.6       7.8253e+06        7.7982e+06        7.8525e+06
16171.7       3.3591e+06        3.3541e+06        3.3641e+06
16181.9       7.9905e+06        7.9842e+06        7.9969e+06
18743.0       5.4436e+06        5.3455e+06        5.5453e+06
20427.0       1.6445e+06        1.6275e+06        1.6618e+06
21479.0       3.0290e+06        2.9492e+06        3.1132e+06
21778.0       3.2835e+06        3.1820e+06        3.3918e+06
23700.5       3.6209e+06        3.5827e+06        3.6598e+06
27289.6       7.7802e+06        7.7398e+06        7.8211e+06
29031.4       4.5482e+06        4.5277e+06        4.5688e+06
29140.5       3.2060e+06        3.1774e+06        3.2352e+06
29225.4       8.4552e+06        8.3776e+06        8.5342e+06
29736.5       1.3035e+06        1.2968e+06        1.3103e+06
29786.7       1.7871e+06        1.7611e+06        1.8139e+06
31031.2       2.1918e+06        2.1512e+06        2.2338e+06
31920.7       6.5775e+06        6.5404e+06        6.6151e+06

Attachment 5: ringdown_rawdata_2016_10_19.m
%% Parameters
prefix = '2016_10_19';  % name of the folder where result will be saved
gps0 = 1160949234;      % GPS time of clean data before excitation
gps1 = 1160949284;      % GPS time right after excitation
dt = 30;                % how much data to be used to search peaks

minsnr = 6;             % minimum peak SNR
minfr = 1000;           % minimum peak frequency
Dt = 3600;              % total amount of time for the ringdown measurement


... 274 more lines ...
137   Wed Oct 19 16:40:24 2016 sults:GeneralMeasurementsS1600349

# S1600439, not annealed, as received from Mark Optics

## Installation

• installed and balanced, pump down started at 4:38pm (roughing pump), turbo started at 4:51pm
• removed from the chamber on 10/20 at about 11:00am

## Measurements

### 2016_10_19

• QPD centered at 9:25pm, excited (2000 V, 10 s) at 9:27pm, measurement ongoing.

The spectrum was noise than usual due to the roughing pump. I already found out in the past that I can reduce the noise by tweaking the position of the pump. This time however I wasn't successful.

Here are the results:

% Freq        Q                 Qlow (C.I. 95%)   Qhi (C.I. 95%)
1111.5        6.0958e+06        6.0641e+06        6.1279e+06
2549.6        3.6416e+06        3.6305e+06        3.6528e+06
4441.7        2.6916e+06        2.6879e+06        2.6953e+06
4512.9        2.1090e+05        2.0993e+05        2.1188e+05
6777.5        1.1797e+06        1.1790e+06        1.1803e+06
6790.9        3.8621e+06        3.8540e+06        3.8701e+06
6858.4        1.2434e+06        1.2295e+06        1.2577e+06
9548.0        1.2177e+05        1.1878e+05        1.2491e+05
10234.6       3.9934e+05        3.9351e+05        4.0535e+05
10399.0       2.8135e+05        2.7455e+05        2.8849e+05
12744.2       1.3145e+06        1.3115e+06        1.3174e+06
14211.3       3.8414e+06        3.8136e+06        3.8696e+06
16123.3       2.0276e+06        2.0181e+06        2.0372e+06
16135.8       5.2811e+06        5.2770e+06        5.2852e+06
16370.0       1.4976e+06        1.4922e+06        1.5031e+06
18689.3       4.2954e+06        4.2738e+06        4.3172e+06
23632.0       2.2796e+06        2.2528e+06        2.3070e+06
24797.4       8.7545e+05        8.5819e+05        8.9341e+05
27214.5       1.2566e+06        1.2374e+06        1.2764e+06
28947.5       1.7367e+06        1.7130e+06        1.7611e+06
29144.0       3.2148e+06        3.1213e+06        3.3142e+06

### 2016_10_20

• Roughing pump was creating too much noise, switched it off at 8:30am
• Excitation at 8:35am (2000 V, 30 s)

Here are the results:

And the measured Q values:

% Freq        Q                 Qlow (C.I. 95%)   Qhi (C.I. 95%)
1111.4        6.2206e+06        6.2061e+06        6.2351e+06
2549.6        4.1538e+06        4.1498e+06        4.1579e+06
2592.9        1.0952e+06        1.0887e+06        1.1017e+06
4441.7        2.8521e+06        2.8513e+06        2.8529e+06
4513.0        2.0592e+05        2.0455e+05        2.0730e+05
6777.5        1.1013e+06        1.1006e+06        1.1020e+06
6790.9        3.9913e+06        3.9879e+06        3.9947e+06
6858.2        1.3100e+06        1.3078e+06        1.3122e+06
9547.8        1.2492e+06        1.2469e+06        1.2514e+06
10234.7       3.4336e+06        3.4209e+06        3.4463e+06
10398.7       4.3217e+05        3.2860e+05        6.3104e+05
12744.2       4.5274e+05        4.5177e+05        4.5371e+05
14211.3       2.0254e+06        2.0081e+06        2.0430e+06
16123.0       2.1225e+06        2.1173e+06        2.1276e+06
16135.8       4.6547e+06        4.6529e+06        4.6564e+06
16370.3       1.4781e+06        1.4762e+06        1.4800e+06
18689.2       4.5978e+06        4.5891e+06        4.6064e+06
20299.5       4.1859e+05        4.1375e+05        4.2353e+05
20364.6       1.1099e+06        1.0630e+06        1.1612e+06
21418.2       4.5814e+06        4.5718e+06        4.5911e+06
23631.9       2.8907e+06        2.8700e+06        2.9116e+06
24797.4       1.1241e+06        1.1121e+06        1.1363e+06
27214.5       2.1015e+06        2.0752e+06        2.1285e+06
28947.3       2.1285e+06        2.1162e+06        2.1410e+06
29054.7       1.4873e+06        1.4631e+06        1.5124e+06
29143.8       4.1250e+06        4.1050e+06        4.1453e+06
29647.5       4.5456e+05        4.4215e+05        4.6768e+05
31135.4       7.5136e+05        7.3331e+05        7.7033e+05
32013.4       1.1846e+06        1.1565e+06        1.2140e+06
Attachment 9: ringdown_rawdata_2016_10_19.m
%% Parameters
prefix = '2016_10_19';  % name of the folder where result will be saved
gps0 = 1160972805;      % GPS time of clean data before excitation
gps1 = 1160972852;      % GPS time right after excitation
dt = 30;                % how much data to be used to search peaks

minsnr = 6;             % minimum peak SNR
minfr = 1000;           % minimum peak frequency
Dt = 3600;              % total amount of time for the ringdown measurement


... 274 more lines ...
Attachment 10: ringdown_rawdata_2016_10_20.m
%% Parameters
prefix = '2016_10_20';  % name of the folder where result will be saved
gps0 = 1161012900;      % GPS time of clean data before excitation
gps1 = 1161012972;      % GPS time right after excitation
dt = 30;                % how much data to be used to search peaks

minsnr = 6;             % minimum peak SNR
minfr = 1000;           % minimum peak frequency
Dt = 3600;              % total amount of time for the ringdown measurement


... 274 more lines ...
138   Wed Oct 19 17:08:47 2016 GabrieleGeneralMeasurementsS1600433 vs S1600438
• S1600433 has been annealed, was contaminated by the iron oxide, and it was cleaned using first contact. No residual were visible on the surface during a simple eye inspection (no flash light)
• S1600438 is as received from Mark Optics. Some particules are visible on the surfaces with a flash light

The plot below compares the Q values measured today for the two disks. The disk that was annealed and cleaned clearly shows lower Q's for almost all modes.

139   Thu Oct 20 11:04:03 2016 GabrieleGeneralMeasurementsSample with flame polished edges

# Sample with edges flame polished in Glasgow

## Installation

• into the chamber and balanced at 11am. Pump down started at 11:00am.
• it looks like the turbo pump shaked the sample too much and moved it significantly. At 11:44am I had to tweak a bit the input steering periscope to avoid the outgoing beam to be clipped on the pickoff mirror
• roughing pump off at 2:27pm
• excitation at 2:36pm (2000 V, 30 s)

## Results

% Freq        First Q of pair   Second Q of pair
1117.4        2.3392e+07        2.3392e+07
2555.9        1.8650e+07        1.8650e+07
4441.1        1.3003e+07        1.3003e+07
6759.2        1.6003e+07        1.5656e+07
6781.8        1.4795e+07        1.4795e+07
9499.2        5.6765e+06        5.6765e+06
10219.5       1.3148e+07        2.7060e+06
10222.3       1.3909e+07        4.2609e+04
11444.0       2.0756e+06        6.5364e+05
12649.4       1.0264e+07        8.7228e+06
12650.7       8.6808e+06        8.6808e+06
14176.3       1.0290e+07        1.0290e+07
14177.5       1.0185e+07        1.0185e+07
16113.7       1.0856e+07        9.7535e+06
16202.5       8.6733e+06        5.0176e+06
18619.0       1.3113e+07        1.3113e+07
18622.1       1.4864e+07        1.4864e+07
20149.0       1.4047e+06        1.4047e+06
21348.8       6.9944e+06        6.9944e+06
21353.3       8.0679e+06        3.1734e+05
23529.5       1.3076e+07        1.3076e+07
24482.3       9.6841e+06        9.6841e+06
24669.1       4.8629e+06        4.8629e+06
24670.5       6.3609e+06        6.3609e+06
25499.2       5.2216e+06        5.2216e+06
25828.0       3.3780e+06        3.3780e+06
27101.0       1.4934e+07        1.4934e+07
27103.5       1.4956e+07        1.4956e+07
28883.5       1.2076e+07        1.2076e+07
29068.6       1.1494e+07        1.1494e+07
29072.0       9.7555e+06        9.7555e+06
29190.0       5.9610e+06        5.9610e+06
29193.2       7.9280e+06        7.9280e+06
29502.2       7.8254e+06        7.8254e+06
30867.0       6.3681e+06        6.3681e+06
31267.0       1.6836e+06        1.4541e+05
32194.4       5.3275e+06        5.3275e+06
32200.0       5.9215e+06        2.6587e+06

The following plot compares the Q measured on this sample yesterday here at Caltech with the GeNS system, with the measurement perfomed by Raymond Robie in Glasgow.

- blue dots: measurements on the flame polished sample here at Caltech
- orange crosses and yellow triangles: Raymond’s measurements on the flame polished sample at in Glasgow (after annealing)
- purple crosses: typical Q values measured on disk samples (not annealed nor flame polished) here at Caltech

Flame polishing of the edges did not change significantly the Q we measure with the GeNS system. However, the GeNS system rovide systematically higher Q values for basically all measurable modes.

Attachment 7: ringdown_raw_data_2016_10_20.m
%% Parameters
prefix = '2016_10_20';  % name of the folder where result will be saved
gps0 = 1161034552;      % GPS time of clean data before excitation
gps1 = 1161034619;      % GPS time right after excitation
dt = 30;                % how much data to be used to search peaks

minsnr = 6;             % minimum peak SNR
minfr = 1000;           % minimum peak frequency
Dt = 3600;              % total amount of time for the ringdown measurement


... 303 more lines ...
141   Fri Oct 21 13:45:21 2016 GabrieleGeneralMeasurementsS1600447

# Sample S1600447, as received from Mark Optics, second batch

## Measurements

• Installed into the chamber, pumping down started at ~1:10pm

### 2016-10-21

• Excited at 3:38pm, amplitude 2kV, duration 30 s
• Excited at 5:01:30pm, amplitude 3kV, duration 30 s
• Excited at 9:11:30pm, amplitude 3kV, duration 30 s

### 2016-10-23

• Excited at 9:34:38am, amplitude 3kV duration 30 s

## Results

All measured Q values are very low. Details below, here's a summary of all four measurements:

### 2016-10-21 9:11pm

144   Mon Oct 24 10:26:30 2016 GabrieleGeneralMeasurementsS1600439

# S1600439, post annealing

Measurements before annealing reported in elog 137. Details on the annealing run here: T1600476

## Installation

• at 10:15am turbo pump switched off
• installed at 11:15am, pumping down
• pumps stopped at 2:49pm
• sample out of the chamber at 4:25pm

## Measurements

• excited at 1:05:40pm, amplitude 3kV, duration 30 s

All Q values are increased with respect to pre-annealing

145   Mon Oct 24 14:33:46 2016 GabrieleGeneralMeasurementsEffect of annealing: Q increases

S1600439 has been measured as received (before annealing, elog 137) and after annealing (elog 144).

Q values are significantly increased for almost all modes, see the plot below for a comparison. Only modes with low Q are not improved.

146   Mon Oct 24 16:32:01 2016 GabrieleGeneralMeasurementsS1600448

# Sample S1600447, as received from Mark Optics, second batch

• in chamber, pumping down at 4:30pm (2016-10-24)
• pumps stopped at 9:18am (2016-10-25)
• vented, sample of the chamber at 10:00aa

## Summary

Measured Q values are low.

## 2016-10-24

• excited at 8:38:48pm, amplitude 3 kV, duration 30s

## 2016-10-25

• excited at 8:05:20am, amplitude 3kV, duration 30s

147   Tue Oct 25 09:12:31 2016 GabrieleGeneralMeasurementsComparison of first and second batch

The plot below compares a sample from the first batch and two samples from the second batch. All samples are as received from Mark Optics, no annealing or any other treatment.

Both samples in the second batch show consistently and significantly lower Q values.

GariLynn and I inspected the two samples under the microscope. Surprisingly, the edges and the flats look much better than the samples from the first batch. See elog 148 for an image of a sample from the first batch

Attachment 2: IMG_3155.JPG
Attachment 3: IMG_3158.JPG
Attachment 4: IMG_3157.JPG
Attachment 5: IMG_3156.JPG
Attachment 6: IMG_3155.JPG
148   Tue Oct 25 11:10:37 2016 GabrieleGeneralMeasurementsImage of S1600433

This is an image of the sample S1600433 under the microscope, courtesy of GariLynn:

The scale in the image is 20 microns per divison, 2 mm full scale

Attachment 1: IMG_3150.JPG
150   Fri Oct 28 21:20:48 2016 GabrieleGeneralMeasurementsS1600447 post annealing

## Installation

I had some problems in installing the wafer. I balanced it and started the pump down a couple of times, and the wafer moved so that the beam coming out of the chamber was clipping.

I decided to re-align the optical setup again. As before, I used a small container with water to have the horizontal reference, and aligned the output optics to center on the QPD. I also added a iris before the mirror with the picomotors, as additional reference.

During pump down I noticed a few sudden jumps of the QPD signals. The output beam moved a lot again, so my realignment didn't help. I even tried to slow down the pump, but this didn't help either. To recover the beam on the pick-off mirror, I had to move a bit the upper periscope mirror. So my horizontal reference is no more good.

It's not clear what's going on, but I'll keep pumping down.

• installed on 10/28 at 9:00pm, pumping down. Turbo started at 9:09pm, The beam is slowly drifting but nothing to be worried about. Pressure is 5.9e-6 Tor at 9:20pm.
• autocentering script on at 9:18pm
• started a set of measurements at 9:20pm. Three excitations (3 kV, 30s). The first one will start in 2h, then the others will follow with an interval of three hours between them. A python script (auto_excite.py) is running on the workstation
• stopped pumps at 9:30 am 10/29

I noticed another strange thing: when I switchec the IGM vacuum gauge on, the QPD signal changed, as if the beam moved. See figure below.

## Measurements

Excitation at 1161757257 (30 s)
Excitation at 1161757309 (30 s)
Excitation at 1161757361 (30 s)

Something went wrog with the script (some python issue I still don't understand) so the three excitations were executed in sequence. In summary, only one ring-down measurement.

## Results

Here are the plots from the ringdown measurement:

And the fitted Q factors:

% Freq        Q                 Q (C.I. 95%)      Q (C.I. 95%)
1115.3        1.2185e+07        1.2167e+07        1.2202e+07
2558.9        4.1466e+06        4.1430e+06        4.1501e+06
4456.9        2.5958e+06        2.5927e+06        2.5989e+06
4523.6        9.6000e+04        9.5990e+04        9.6011e+04
6798.5        1.9687e+06        1.9596e+06        1.9777e+06
6813.2        7.7644e+06        7.7608e+06        7.7680e+06
6876.3        1.0955e+06        1.0947e+06        1.0963e+06
9575.1        2.5100e+06        2.5061e+06        2.5139e+06
10270.5       8.1293e+06        8.0671e+06        8.1925e+06
12904.0       2.8481e+05        2.8480e+05        2.8482e+05
14259.5       4.9009e+06        4.8836e+06        4.9184e+06
16176.3       1.6116e+06        1.6097e+06        1.6135e+06
16187.8       5.7721e+06        5.7689e+06        5.7753e+06
16406.5       1.8723e+06        1.8676e+06        1.8769e+06
18751.4       1.0901e+06        1.0900e+06        1.0901e+06
20410.0       5.4342e+05        5.4341e+05        5.4343e+05
21485.0       7.3955e+06        7.3284e+06        7.4639e+06
23709.9       5.1619e+06        5.1426e+06        5.1813e+06
24845.0       1.3831e+06        1.3787e+06        1.3876e+06
29140.4       2.1742e+06        2.1742e+06        2.1742e+06
29231.0       6.8560e+06        6.8559e+06        6.8562e+06`

Attachment 5: Qs.png
ELOG V3.1.3-