2017-06-30

MIT sample 1 (bare disk)

2016-11-28

3:00pm: removed the retaining ring and the alignment pins
3:05pm, 100mm/0.5mm disk installed, balanced
3:06pm, roughing pump on
3:19pm, turbo pump on
Excitations:
- quiet time before 1164414276
  band pass 100-3000 Hz, amplitude 3 x 2 kV, 60 seconds
  quiet time after 1164414439
- Quiet time before excitation: 1164426582
  Excitation (broad band) at 1164426615 (60 s)
  Quiet time after excitation: 1164426677
- Quiet time before excitation: 1164437507
  Excitation (broad band) at 1164437539 (60 s)
  Quiet time after excitation: 1164437601
- Quiet time before excitation: 1164448433
  Excitation (broad band) at 1164448465 (60 s)
  Quiet time after excitation: 1164448527

2016-11-29

10:02am, pumps off

Results

2016-11-28 A

% Freq        Q1                Q2
315.9         2.8096e+06        2.8096e+06
726.7         1.8635e+06        1.8635e+06
1265.9        1.4194e+06        1.4029e+06
1930.4        1.1427e+06        1.1427e+06
1945.3        3.8068e+06        3.8068e+06
2717.9        9.7820e+05        9.6825e+05
2937.1        2.9339e+06        2.8810e+06
3626.4        8.4222e+05        8.4139e+05
4082.7        2.4345e+06        2.3090e+06
4638.8        5.2362e+06        5.1759e+06
4654.2        7.4042e+05        7.4042e+05
5374.9        1.9928e+06        1.9928e+06
5800.3        6.7081e+05        6.6269e+05
6164.3        4.0627e+06        3.8329e+06
6808.9        1.8131e+06        1.7073e+06
7063.0        6.2208e+05        6.2066e+05
7849.1        3.0518e+06        3.0518e+06
8381.5        1.6107e+06        1.6105e+06
10089.4        1.3860e+06        1.3793e+06
10476.0        4.6551e+06        4.6551e+06
12692.5        3.7473e+06        3.7473e+06

2016-11-28 B

% Freq        Q1                Q2
316.2         2.9559e+06        2.9559e+06
726.7         1.9471e+06        1.9471e+06
1265.9        1.4767e+06        1.4596e+06
1324.0        1.7317e+06        1.7317e+06
1930.3        1.1866e+06        1.1826e+06
1945.2        3.8606e+06        3.8606e+06
2247.0        1.2821e+06        1.2442e+06
2717.8        1.0111e+06        9.8894e+05
2936.9        2.9926e+06        2.9494e+06
3626.2        8.6881e+05        8.6809e+05
4082.4        2.4804e+06        2.3513e+06
4638.7        5.2732e+06        5.1865e+06
4654.1        7.6228e+05        7.6228e+05
5374.6        2.0240e+06        2.0240e+06
5800.0        6.8894e+05        6.7200e+05
6164.1        3.9378e+06        3.9270e+06
6808.7        1.8616e+06        1.7343e+06
7062.7        6.2617e+05        6.2617e+05
7849.0        3.1323e+06        3.1323e+06
8381.2        1.6487e+06        1.5110e+06
8419.4        6.2761e+06        6.0088e+06
9687.4        2.6263e+06        2.6263e+06
10088.7        1.4209e+06        1.4209e+06
10475.5        4.5819e+06        3.9452e+06
11929.4        2.0706e+06        8.4521e+05
13900.0        1.1087e+06        1.1087e+06

2016-11-29 C

% Freq        Q1                Q2
316.1         3.0133e+06        3.0133e+06
726.7         1.9621e+06        1.9621e+06
1265.8        1.4754e+06        1.4754e+06
1324.0        1.5486e+06        1.5486e+06
1930.3        1.1968e+06        1.1968e+06
1945.2        3.8326e+06        3.8326e+06
2717.8        1.0236e+06        9.9498e+05
2937.0        3.0102e+06        2.9815e+06
3626.2        8.7624e+05        8.7624e+05
4082.3        2.4965e+06        2.3709e+06
4638.6        5.2551e+06        5.2551e+06
4654.0        7.6848e+05        7.6176e+05
5374.4        2.0713e+06        2.0713e+06
6164.0        4.6657e+06        4.6657e+06
6808.7        1.8860e+06        1.7018e+06
8381.1        1.6553e+06        1.6553e+06
8419.0        6.3696e+06        6.3696e+06

214

Tue Nov 29 11:26:46 2016

MIT sample 2 (disk with 4 1"/0.1mm glued blanks)

2016-11-19

11:24am, in chamber, balanced. Installed with the four glued blanks facing down
11:25am, roughing pump on
11:35am, turbo pump on
Excitations
- Quiet time before excitation: 1164492579
  Excitation (broad band) at 1164492611 (60 s) NOTE:stopped short of planned end time
  Quiet time after excitation: 1164492673
~2:40pm, Roughing pump off
- Quiet time before excitation: 1164494418
  Excitation (broad band) at 1164494450 (60 s)
  Quiet time after excitation: 1164494512
Reduced excitation amplitude by a factor 2
- Quiet time before excitation: 1164496302
  Excitation (broad band) at 1164496334 (60 s)
  Quiet time after excitation: 1164496396
Increased excitation back to original value
- Quiet time before excitation: 1164497423
  Excitation (broad band) at 1164497455 (60 s)
  Quiet time after excitation: 1164497517
- Quiet time before excitation: 1164498267
  Excitation (broad band) at 1164498300 (60 s)
  Quiet time after excitation: 1164498362
- Quiet time before excitation: 1164499112
  Excitation (broad band) at 1164499144 (60 s)
  Quiet time after excitation: 1164499206
4:01pm, turbo pump off

Results

2016-11-28 B

% Freq       Q1                Q2
329.0        8.4824e+04        8.4824e+04
335.7        1.4025e+05        1.4025e+05
440.4        9.8646e+03        9.8646e+03
497.0        9.0449e+03        9.0449e+03
776.2        9.3536e+04        9.3536e+04
1112.1        7.1969e+03        7.1969e+03
1350.2        8.7756e+04        8.7756e+04
1358.5        7.4121e+04        7.4121e+04
1552.4        1.8858e+04        1.8858e+04
1609.0        3.3215e+04        3.3215e+04
1784.0        1.1629e+04        1.1629e+04
1798.6        2.0767e+04        2.0767e+04
1888.4        1.7837e+04        1.7837e+04
1945.0        3.3859e+04        3.3859e+04
2030.0        1.0957e+04        1.0957e+04
2050.5        7.5373e+04        7.5373e+04
2080.0        8.8890e+04        8.8890e+04
2134.5        1.1641e+04        1.1641e+04
2416.0        2.1993e+04        2.1993e+04
2470.5        2.7733e+04        2.7733e+04
2520.0        2.2354e+04        2.2354e+04
2527.0        4.5688e+04        4.5688e+04
2856.0        2.0405e+04        2.0405e+04
2874.4        5.1657e+04        5.1657e+04
3192.0        4.0038e+04        4.0038e+04
3438.0        2.4531e+04        2.4531e+04
3528.0        4.3625e+04        4.3625e+04
3810.3        8.4299e+04        8.4299e+04
3812.7        8.4331e+04        8.4331e+04
4214.0        4.5810e+04        4.5810e+04
4379.8        1.2693e+05        1.2693e+05
4550.5        4.2404e+04        4.2404e+04
4867.4        8.2873e+04        8.2873e+04
4870.5        7.8134e+04        7.8134e+04

2016-11-28 D

% Freq        Q1                Q2
335.6         1.4056e+05        1.4056e+05
672.0         1.5677e+05        1.5677e+05
777.6         9.2059e+04        9.2059e+04
1112.7        1.0553e+05        1.0553e+05
1203.1        5.5487e+04        5.5487e+04
1350.1        8.4536e+04        8.4536e+04
1358.4        7.1777e+04        7.1777e+04
1714.6        7.2616e+04        7.2616e+04
2050.5        7.6493e+04        7.6493e+04
2080.0        8.7699e+04        8.7699e+04
2098.0        9.7959e+04        9.7959e+04
2416.0        1.0540e+05        1.0540e+05
2874.4        5.6525e+04        5.6525e+04
3128.9        2.3520e+04        2.3520e+04
3134.3        2.0219e+04        2.0219e+04
3810.5        8.7060e+04        8.7060e+04
3812.5        8.7089e+04        8.7089e+04
4323.4        5.2924e+04        5.2924e+04
4379.8        1.2308e+05        1.2308e+05
4867.1        8.1170e+04        8.1170e+04
4870.4        8.9835e+04        8.9835e+04
5704.3        6.9120e+04        6.9120e+04
5728.4        6.6924e+04        6.6924e+04
6033.9        7.5637e+04        7.5637e+04
6036.0        8.0112e+04        8.0112e+04
7204.0        1.0233e+05        1.0233e+05
8625.9        1.4731e+05        1.4731e+05

215

Tue Nov 29 16:42:51 2016

MIT sample 3 (disk with 4 0.5"/0.125" glued blanks)

2016-11-29

4:40pm, in chamber, blanks facing down
4:41pm, roughing pump on
4:53pm, turbo pump on
Injections:
- Quiet time before excitation: 1164516798
  Excitation (broad band) at 1164516830 (60 s)
  Quiet time after excitation: 1164516892
- Quiet time before excitation: 1164518722
  Excitation (broad band) at 1164518754 (60 s)
  Quiet time after excitation: 1164518816
- Quiet time before excitation: 1164520646
  Excitation (broad band) at 1164520678 (60 s)
  Quiet time after excitation: 1164520740
- Quiet time before excitation: 1164522570
  Excitation (broad band) at 1164522602 (60 s)
  Quiet time after excitation: 1164522664
- Quiet time before excitation: 1164524494
  Excitation (broad band) at 1164524526 (60 s)
  Quiet time after excitation: 1164524588
- Quiet time before excitation: 1164526419
  Excitation (broad band) at 1164526451 (60 s)
  Quiet time after excitation: 1164526513

2016-11-30

9:05am, pumps off

Results

2016-11-29 A

% Freq       Q1                Q2
251.9        2.8630e+04        2.8630e+04
270.6        4.3984e+04        4.3984e+04
329.0        5.2792e+04        5.2792e+04
387.4        6.4408e+04        6.4408e+04
692.9        2.1202e+04        2.1202e+04
705.5        2.7294e+04        2.7294e+04
1121.5        1.9490e+04        1.9490e+04
1127.2        2.3102e+04        2.3102e+04
1242.2        1.6168e+04        1.6168e+04
1318.1        2.5395e+04        2.5395e+04
1800.6        2.3235e+04        2.3235e+04
2124.1        1.8960e+04        1.8960e+04
2797.5        9.8183e+03        9.8183e+03
2841.8        1.1002e+04        1.1002e+04
2921.3        1.2820e+04        1.2820e+04
2959.7        7.8878e+03        7.8878e+03
3701.0        8.0007e+03        8.0007e+03
3839.4        1.3538e+04        1.3538e+04
4692.3        3.4420e+04        3.4420e+04

2016-11-29 B

% Freq        Q1                Q2
251.9         2.6513e+04        2.6513e+04
329.0         5.4964e+04        5.4964e+04
387.0         5.9983e+04        5.9983e+04
692.9         2.4150e+04        2.4150e+04
705.4         2.7301e+04        2.7301e+04
1127.3        1.8674e+04        1.8674e+04
1242.1        1.2792e+04        1.2792e+04
1318.1        2.4187e+04        2.4187e+04
1800.7        2.2498e+04        2.2498e+04
2124.2        1.8534e+04        1.8534e+04
2797.5        9.8734e+03        9.8734e+03
2841.6        1.2921e+04        1.2921e+04
2959.8        1.0940e+04        1.0940e+04
3400.4        1.5128e+04        1.5128e+04
3700.7        1.0732e+04        1.0732e+04
4692.2        4.3243e+04        4.3243e+04

2016-11-29 C

% Freq        Q1                Q2
251.6         2.8079e+04        2.8079e+04
271.0         4.1437e+04        4.1437e+04
329.0         5.4328e+04        5.4328e+04
387.4         5.8614e+04        5.8614e+04
692.8         2.2689e+04        2.2689e+04
705.5         2.8442e+04        2.8442e+04
1127.2        1.8216e+04        1.8216e+04
1242.0        1.8455e+04        1.8455e+04
1317.8        2.3628e+04        2.3628e+04
1800.6        2.2896e+04        2.2896e+04
2124.2        1.8450e+04        1.8450e+04
2797.7        1.0904e+04        1.0904e+04
2841.8        1.4721e+04        1.4721e+04
2921.4        1.0612e+04        1.0612e+04
2959.8        1.0875e+04        1.0875e+04
3700.7        1.1009e+04        1.1009e+04
3705.3        1.0344e+04        1.0344e+04
3839.3        1.3205e+04        1.3205e+04
4110.4        1.3077e+04        1.3077e+04
4692.3        4.8605e+04        4.8605e+04

234

Wed Dec 7 09:59:59 2016

MIT sample 3 (disk with 4 0.5"/0.125" glued blanks) second round

2016-12-07

Removed retaining ring and pins, aligned optical setup to horizontal reference
9:59am, in chamber, balanced
10:00am, roughing pump on
10:12am, turbo pump on

As visible in th second picture, the distance between the disk and the ESD is about 1.5 mm

Excitations:
- Quiet time before excitation: 1165178719
  Excitation (broad band) at 1165178751 (60 s)
  Quiet time after excitation: 1165178813
- Quiet time before excitation: 1165180007
  Excitation (broad band) at 1165180039 (60 s)
  Quiet time after excitation: 1165180101
- Quiet time before excitation: 1165181331
  Excitation (broad band) at 1165181363 (60 s)
  Quiet time after excitation: 1165181425
2:39pm, pumps off

Results

2016-12-07 A

% Freq        Q               Q (C.I. 95%)        Q (C.I. 95%)
251.8        2.9528e+04        2.9325e+04        2.9732e+04
323.4        6.9039e+04        6.5071e+04        7.3509e+04
328.7        5.5337e+04        5.5222e+04        5.5453e+04
692.8        2.4543e+04        2.4515e+04        2.4571e+04
705.5        2.7474e+04        2.7356e+04        2.7592e+04
1128.5        2.1332e+04        2.1268e+04        2.1395e+04
1242.4        1.2258e+04        1.2079e+04        1.2442e+04
1318.0        2.4548e+04        2.4419e+04        2.4678e+04
1800.7        2.6692e+04        2.6451e+04        2.6937e+04
1933.3        9.2002e+03        8.9167e+03        9.5022e+03
1937.7        8.5766e+03        8.5339e+03        8.6198e+03
2124.0        2.4927e+04        2.4872e+04        2.4982e+04
2799.2        8.1222e+03        7.9880e+03        8.2609e+03
2924.5        8.1070e+03        8.0349e+03        8.1804e+03
2964.4        8.2661e+03        8.1772e+03        8.3570e+03
4692.7        4.5716e+04        4.4885e+04        4.6578e+04

2016-12-07 B

% Freq        Q                Q (C.I. 95%)        Q (C.I. 95%)
251.7        2.8324e+04        2.8084e+04        2.8567e+04
329.0        5.4343e+04        5.4182e+04        5.4504e+04
692.7        2.4556e+04        2.4524e+04        2.4588e+04
705.5        2.7344e+04        2.7229e+04        2.7461e+04
1128.3        2.0844e+04        2.0548e+04        2.1148e+04
1242.1        1.2091e+04        1.1999e+04        1.2185e+04
1317.8        2.4709e+04        2.4659e+04        2.4760e+04
1322.0        2.8932e+04        2.6985e+04        3.1179e+04
1800.6        2.6879e+04        2.6691e+04        2.7069e+04
2123.6        2.4719e+04        2.4619e+04        2.4820e+04
2798.1        9.5908e+03        9.2072e+03        1.0008e+04
2841.0        1.1254e+04        1.0614e+04        1.1976e+04
2924.0        1.1666e+04        1.0395e+04        1.3291e+04
2963.1        9.7910e+03        9.3703e+03        1.0251e+04
3427.6        8.7265e+03        8.2911e+03        9.2102e+03
3700.2        1.4646e+04        1.3418e+04        1.6120e+04
4691.8        5.0056e+04        4.7715e+04        5.2638e+04

2016-12-07 C

% Freq        Q               Q (C.I. 95%)        Q (C.I. 95%)
251.8        2.8868e+04        2.8741e+04        2.8997e+04
313.8        4.8299e+04        4.4161e+04        5.3275e+04
658.0        4.5409e+04        4.4859e+04        4.5971e+04
692.6        2.4089e+04        2.3929e+04        2.4251e+04
705.4        2.7821e+04        2.7639e+04        2.8006e+04
1128.2        2.1583e+04        2.1087e+04        2.2103e+04
1242.1        1.2540e+04        1.2303e+04        1.2786e+04
1317.9        2.4663e+04        2.4626e+04        2.4700e+04
1571.0        1.4941e+04        1.4265e+04        1.5685e+04
1800.4        2.8559e+04        2.8113e+04        2.9019e+04
2123.4        2.7042e+04        2.6498e+04        2.7608e+04
2452.3        2.9667e+04        2.8231e+04        3.1256e+04
2797.4        8.7540e+03        8.0589e+03        9.5802e+03
2840.2        1.3484e+04        1.2967e+04        1.4043e+04
3706.5        1.0864e+04        1.0328e+04        1.1457e+04
4107.6        1.5757e+04        1.5573e+04        1.5946e+04
4690.7        4.8903e+04        4.7899e+04        4.9949e+04

2016-12-07 D

% Freq        Q               Q (C.I. 95%)        Q (C.I. 95%)
251.8        2.9311e+04        2.9189e+04        2.9434e+04
323.2        2.7246e+04        2.4352e+04        3.0908e+04
692.6        2.4309e+04        2.4226e+04        2.4392e+04
698.0        1.7009e+04        1.5425e+04        1.8954e+04
702.0        2.7209e+04        2.6645e+04        2.7796e+04
705.5        3.0025e+04        2.9300e+04        3.0785e+04
1127.6        2.0285e+04        1.9811e+04        2.0781e+04
1317.3        2.5325e+04        2.5209e+04        2.5442e+04
1800.3        3.2511e+04        3.1223e+04        3.3909e+04
1935.2        6.5014e+03        4.9517e+03        9.4607e+03
2122.5        2.8808e+04        2.7758e+04        2.9940e+04
2795.4        1.0237e+04        8.7193e+03        1.2393e+04
4688.8        4.9909e+04        4.1120e+04        6.3475e+04
6847.5        7.9848e+03        7.7352e+03        8.2510e+03

218

Wed Nov 30 10:02:20 2016

MIT sample 4 (disk with 3 1"/0.1mm glued blanks)

2016-11-30

9:57am, in chamber, balanced, glued balnks facing down
9:59am, roughing pump on
10:09am, turbo pump on
Excitations
- Quiet time before excitation: 1164570059
  Excitation (broad band) at 1164570091 (60 s)
  Quiet time after excitation: 1164570153
- Quiet time before excitation: 1164571983
  Excitation (broad band) at 1164572015 (60 s)
  Quiet time after excitation: 1164572077
- Quiet time before excitation: 1164573907
  Excitation (broad band) at 1164573939 (60 s)
  Quiet time after excitation: 1164574001
- Quiet time before excitation: 1164575831
  Excitation (broad band) at 1164575863 (60 s)
  Quiet time after excitation: 1164575925
3:34pm, pumps off

Results

2016-11-30 A

% Freq        Q1                Q2
329.0         8.3663e+04        8.3663e+04
764.8         6.6913e+04        6.6913e+04
1093.6        7.4978e+04        7.4978e+04
1173.2        4.7789e+04        4.7789e+04
1333.5        5.8904e+04        5.8904e+04
1529.0        6.9659e+04        6.9659e+04
1597.4        1.0552e+05        1.0552e+05
1748.0        4.8237e+04        4.8237e+04
2007.8        3.8014e+04        3.8014e+04
2017.3        6.4686e+04        6.4686e+04
2066.8        4.6047e+04        4.6047e+04
2077.3        5.7698e+04        5.7698e+04
2832.1        4.1680e+04        4.1680e+04
2850.9        6.3764e+04        6.3764e+04
3101.5        2.6027e+04        2.6027e+04
3468.7        1.9827e+04        1.9827e+04
3784.7        3.5492e+04        3.5492e+04
4301.1        3.6826e+04        3.6826e+04
4822.6        6.6123e+04        6.6123e+04
4834.9        4.6789e+04        4.6789e+04
6014.6        6.6507e+04        6.6507e+04

2016-11-30 B

% Freq        Q
328.8         8.5064e+04
764.6         6.7065e+04
1093.6        6.4289e+04
1173.2        4.7921e+04
1333.5        5.8311e+04
1529.0        6.4720e+04
1597.4        1.5015e+05
1748.4        4.2924e+04
2007.7        4.1694e+04
2017.4        6.3609e+04
2067.0        4.6240e+04
2077.2        5.8395e+04
2406.0        4.5908e+04
2832.1        4.5323e+04
2851.0        6.4089e+04
3101.5        2.9677e+04
3468.7        1.6697e+04
3784.5        2.1703e+04
4299.7        3.7688e+04
4835.1        4.6841e+04
5659.7        3.4913e+04

2016-11-30 C

% Freq        Q
329.1         8.3839e+04
658.0         8.6457e+04
764.6         6.6619e+04
1093.7        7.3246e+04
1163.3        2.7214e+04
1172.5        4.1708e+04
1333.7        5.9429e+04
1597.4        1.4036e+05
1748.0        2.8271e+04
2007.8        4.7532e+04
2017.4        6.5563e+04
2067.0        4.5528e+04
2077.2        5.8753e+04
2346.0        3.4762e+04
2832.1        3.9431e+04
2851.1        6.4498e+04
3101.5        3.0334e+04
3469.0        1.6427e+04
3784.7        5.0161e+04
4299.8        4.0081e+04
4835.2        5.3962e+04
4860.0        5.4326e+04
5659.8        3.5224e+04
6015.4        4.6382e+04
8739.5        4.7841e+04

255

Fri Jan 6 11:23:10 2017

This is one of the samples we got from the first batch, no flats, edge not polished

2017-01-06

11:10am, in chamber, balanced
11:11am, roughing pump on
11:23am, turbo pump on
Excitations:
- Quiet time after excitation 1167770663
- Quiet time before excitation: 1167781499
  Excitation (broad band) at 1167781532 (60 s)
  Quiet time after excitation: 1167781594
- Quiet time before excitation: 1167792424
  Excitation (broad band) at 1167792457 (60 s)
  Quiet time after excitation: 1167792519
- Quiet time before excitation: 1167803349
  Excitation (broad band) at 1167803381 (60 s)
  Quiet time after excitation: 1167803443
- Quiet time before excitation: 1167814274
  Excitation (broad band) at 1167814306 (60 s)
  Quiet time after excitation: 1167814368

2017-01-10

10:15am pumps stopped

Results

2017-01-06A

2017-01_06B

2017-01-06C

2017-01-06D

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.

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.

104

Tue Aug 23 09:44:11 2016

Measurements on MO-02

Two good ring-downs measurements were performed on MO-02. The first one was already reported in a previous elog entry. I performed another measurement, and refined the mode identification. I think I had misidentified some modes in my previous analysis. The following plot shows the difference between the modes as predicted by COMSOL and as measured. A clean quadratic trend is visible and fitted:

Here's the spectrum with all the modes:

And the updated Q measurement plot:

A second ring down was measured on Monday morning . Here are the relevant plots:

This is the same disk as before, but almost all Q values are systematically higher. Here's a direct comparison:

I'm not sure what changed between the two measurements, except for a re-alignment of the QPD. The disk might have moved a bit...

210

Wed Nov 23 14:16:59 2016

Alena

Microscope inspection

Microscope inspection of samples:

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

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

204

Mon Nov 21 11:46:57 2016

Microscope 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.

201

Fri Nov 18 15:48:09 2016

Microscope inspection of CO2 polished samples

S1600470

For reference, this sample has not been CO2 polished, but it has been annealed and measured. It has quite low Q values. Here are some images of the edges. The first two are taken with light from above. In the second one there some clear red residual, which is also visible as a coloration with the naked eye. The microroughness and some larger defect are well visible.

The following images instead are taken with light from below. The red residual is even more evident, and some traces probably due to the machining are clearly visible.

S1600479

This sample has been laser polished with a double pass (first at 0.5 mm/s, second at 0.25 mm/s). The first two images are taken with light from above: they are not very clear because of the specular reflection of the lamps. This already indicates that the surface is much smoother. Some defects (bubbles?) are visible close to the main surfaces.

The surface quality is more apparent in the following pictures, taken with light from below. The second one is taken where there is a chip in the main surface, and indeed one can see the shading due to the light distortion iduced by the chip. Also a cluster of "bubbles" is clearly visible there.

S1600462

This was our first polishing test. It is interesting because the laser tripped during the procedure, so we have a neat transition from the original surface to the polished one. First image taken with light from above, second with light from below

412

Wed Aug 16 11:36:13 2017

2017-08-16

I created a model with a drive offset in the middle. It improved one of the modes by a factor of 14 or so, but overall, it diminished the vast majority of the modes by as much as a factor of 100.

403

Thu Aug 10 11:32:09 2017

Mode peak amplitudes with reference ESD

The uncoated, annealed and CO2 polished substrate S1600541 is installed in chamber CR0. This morning I performed a quick excitation: 1.6kV peak, broadband noise (500Hz - 32768 Hz), duration 20s. I measured the peak amplitude right after the excitation. The first plot below shows the SNR for all the detected 19 modes, as a function of frequency. The second plot shows the peak amplitude in physical units (radians/rHz of disk surface tilt) for all modes. The calibration of the surface motion should be reasonably good, better than a factor 2 of uncertaint. The attached TXT file contains the numerical data.

367

Wed Jul 12 15:08:59 2017

Zach

Electronics

Modeling

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.

Mon Jul 25 12:24:06 2016

Electronics

Configuration

2017-02-28

2:19pm, installed in CR0, balanced, with 1/2" inserts facing down
- It looks dusty and there is a fingerprint on the edge. I didn't clean it
2:21pm, roughing pump on
2:35pm, turbo pump on
Excitations:
- Quiet time before excitation: 1172377933
  Excitation broadband: 1172377965
  Quiet time after excitation: 1172378027
- Quiet time before excitation: 1172381657
  Excitation broadband: 1172381689
  Quiet time after excitation: 1172381751
- Quiet time before excitation: 1172385381
  Excitation broadband: 1172385414
  Quiet time after excitation: 1172385476
- Quiet time before excitation: 1172389106
  Excitation broadband: 1172389138
  Quiet time after excitation: 1172389200
- Quiet time before excitation: 1172392830
  Excitation broadband: 1172392863
  Quiet time after excitation: 1172392925
- Quiet time before excitation: 1172396555
  Excitation broadband: 1172396587
  Quiet time after excitation: 1172396649

2017-03-01

9:36am, pumps stopped

2017-03-02

9:00am. The laser beam was probably hitting one of the glued inserts. Checked that te disk is not touching, moved the ESD a bit lower
9:04am, roughing pump on
9:17am, turbo pump on
1:50pm, pumps off

328

Fri Mar 3 13:01:59 2017

2017-03-03

1:00pm, in chamber, realigned optical lever to get as close as possible to the edge of the disk
1:02pm, roughing pump on
1:14pm, turbo pump on
Excite
- Quiet time before excitation: 1172633160
  Excitation broadband: 1172633192
  Quiet time after excitation: 1172633224
- Quiet time before excitation: 1172634454
  Excitation broadband: 1172634486
  Quiet time after excitation: 1172634518
- Quiet time before excitation: 1172635748
  Excitation broadband: 1172635781
  Quiet time after excitation: 1172635813
- Quiet time before excitation: 1172637043
  Excitation broadband: 1172637075
  Quiet time after excitation: 1172637107
- Quiet time before excitation: 1172638337
  Excitation broadband: 1172638369
  Quiet time after excitation: 1172638401
- Quiet time before excitation: 1172639631
  Excitation broadband: 1172639663
  Quiet time after excitation: 1172639695

2017-03-06

10:18am, pumps off

330

Tue Mar 7 11:09:33 2017

2017-03-07

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

2017-03-08

8:00am pumps restarted
Excitations
- Quiet time before excitation: 1173048953
  Excitation broadband: 1173048986
  Quiet time after excitation: 1173049018
- Quiet time before excitation: 1173050248
  Excitation broadband: 1173050280
  Quiet time after excitation: 1173050312
- Quiet time before excitation: 1173051542
  Excitation broadband: 1173051574
  Quiet time after excitation: 1173051606
- Quiet time before excitation: 1173052836
  Excitation broadband: 1173052868
  Quiet time after excitation: 1173052900
- Quiet time before excitation: 1173054130
  Excitation broadband: 1173054163
  Quiet time after excitation: 1173054195
- Quiet time before excitation: 1173055425
  Excitation broadband: 1173055457
  Quiet time after excitation: 1173055489

2017-03-09

10:10am, pumps off

112

Thu Sep 15 08:27:57 2016

New band-limited excitation

Same as in elog #110, but now the amplitude is proportional to frequency squared:

ampl = (x/x[0])**2
xx = multi_band_noise(bands, ampl, T=20, fs=65536)
n = AWGNoiseStream(4e-4*xx, channel='X3:CR1-ESD_EXC', rate=65536)
n.start()

Noise stopped at 8:27:40am LT.

Turbo pump off and spinning down at 9:37am LT. Pumo completely stopped at 11:15am LT

Openend the chamber and removed the sample at ~11:20am LT

264

Thu Jan 19 07:32:33 2017

Alena

New chamber first pimp down

Vacuum

The new chamber was build. The first attempt to pump down was unsuccessful because of dislocated lid. After the lit was placed properly, the chamber was pumped down to 0.1 torr within 8 min. In future a sky hook will be used to help placing the lid properly. The clamps should not be placed on the lid before the roughing pump turned on.

The turbo pump controller failed. Error code 698 – call the vendor.

266

Thu Jan 19 14:16:53 2017

Mechanics

New concept for retaining ring motion

Since my experiment with coil and magnets didn't work out very well, here's a new concept for the motion of the four retaining rings (all together) using a translation stage and a picomotor. This follows the same idea put forward by Steve Penn. The translation stage is a Newport 9066-COM-V and the picomotor (which we already have) is a Newport 8301-V. Both stage and picomotor are vacuum compatible (rated at 1e-6 Torr) and tested down to 1e-8 Torr by Steve.

Here's the jig integrated in the full system:

Sun Aug 21 08:51:22 2016

Vented the chamber. Installed a new disk (MO 03). The one I measured yesterday is now named MO 02 and it is the one with the "burnt mark" from the previous experiment (due to the electrostatic drive).

Startep roughing pump at 8:50am. Started turbo pump at 9.00am.

Excited the disk at 9:50:30am with white noise, amplitude 10 V. Pumps are still running, pressure is about 2e-6 Torr

At 11:10am I stopped the roughing pump, pressure is 1.4e-6 Torr. Exciting again the disk at 11:10:45am. At 12:25am I checked again the situation, since both measurements look quite weird, especially for the first couple of modes.

I think the reflection from the balck glass is interfering with the reflection from the disk. Probably I wasn't careful enough when I aligned the disk. At about 12:35 I stopped the turbo pump. I'm going to open the chamber and realign everything again.

554

Thu Jul 26 15:33:00 2018

Alena

New 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.

106

Sun Sep 11 10:05:33 2016

New substrate in the chamber

Daily Progress

I installed one of the new substrates (with flats) into the chamber, and started the pumpdown at about 9:45am LT.

Before that, I removed the retaining ring: tomorrow I'm going to glue the magnet to it.

Sun Aug 21 15:36:16 2016

Roughing pump stopped at about 3:30:30pm. HV amplifier on at 3:33:30pm, excitation at 3:35:30pm. Recentered QPD at 3:36pm

Sun Aug 21 17:41:34 2016

I checked the status at about 5:20pm, the turbo pump was in error and spinning down, since the roughing pump has been off for about 1.5 hours.

I let the pump switch off.

Quote:

Roughing pump stopped at about 3:30:30pm. HV amplifier on at 3:33:30pm, excitation at 3:35:30pm. Recentered QPD at 3:36pm

Mon Aug 22 08:29:24 2016

Restarted roughing and turbo pump at about 8:10am.

Quote:

I checked the status at about 5:20pm, the turbo pump was in error and spinning down, since the roughing pump has been off for about 1.5 hours.

I let the pump switch off.

Quote:

Roughing pump stopped at about 3:30:30pm. HV amplifier on at 3:33:30pm, excitation at 3:35:30pm. Recentered QPD at 3:36pm

133

Mon Oct 17 10:50:50 2016

No sign of problems in the electrostatic drive

Vacuum

I opened the chamber and took the etched disk out. Inspection of the electrostatic drive does not show any sign of burn or damage.

So it seems that the problem we had previously was due to contamination of the chamber (in the first case) or of the ESD (in the second case)

170

Wed Nov 9 15:32:11 2016

Noise below 2 kHz is not due to the roughing pump, but to the clean air filters

Noise hunting

The two spectra below show basically no difference (blue roughing pump on, red, roughing pump off)

Instead, below is another comparison: blue same as before, standard condition, red with one of the two clean air filters momentarily off. There is some clear improvement. The second filter is too hard to switch off!

181

Sun Nov 13 10:11:19 2016

The plot below compares the QPD signal spectra in different configurations (roughing pump on/off, air on/off).

The noise below ~<2kHz is making very hard to measure the Q of the first mode at 1100 Hz

The main source of noise are the clean air filters. I switched them to minimum for the moment being.

394

Mon Aug 7 13:19:48 2017

2017-08-07

I included the modal mass factors in the code and renormalized my data. The normalization has a noticeable impact, but does not change the general trends of the data
In fact the impact is not even significant enough to warrant a change in the ideal parameters I picked for the rectangular ESD in my interim report

383

Thu Jul 27 16:56:03 2017

2017-07-27

I ran a low resolution sweep of the offset in the arms of the ESD, the space between the end of the arm and base of the opposite combs. The trends are much more subtle and are not coherent across as many of the modes. The lower frequency modes decrease slightly, while the force in the higher frequency modes increase more drastically. This is an interesting parameter, I will definitely run another sweep once I have written code that accounts for the mode pairs. Assuming the apparent trends are physically accurate, this could be a useful parameter because a greater offset gives a greater relative increase to the higher order modes while still leaving a substantial force on the lower order modes that are excited more easily anyway.

Mon Jul 11 15:21:12 2016

One disk installed into the chamber

Daily Progress

[Alena, Gabriele]

We attached one of the silicon lenses to a 1" optical post using some kapton tape, and installed it into the vacuum chamber. We built a simple periscope using standard optical component, and managed to send the optical level beam into the disk and back out.

To set a reference for the horizontal position of the disk we used the LMA method: we put a small container with water in place of the disk, and mark on a reference where the reflected beam hits out of the chamber:

We then put back the disk, and aligned it to have the beam hitting the same position. During pumdown we couldn't see any shift of the disk, judging from the position of the optical lever beam.

Thu May 19 11:33:44 2016

Electronics

Optical lever electronics design

The circuit design sent out for fabrication is available in the DCC: D1600196

280

Fri Jan 27 14:56:55 2017

Optical lever setup completed

Optics

Daily Progress

The four optical levers are completely installed and aligned to a horizontal reference.

Fri May 20 15:18:58 2016

Optics

Optical levers layout

Attached a first layout of the optical lever systems. The beam spot radius on the QPD is about 0.8 mm, and the lever arm length is of the orer of 1.4-1.5 m for all four beams.

Sun May 22 23:40:45 2016

Optics