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ID Date Author Type Category Subject Text   26   Wed Jun 29 16:44:17 2016 Gabriele General Configuration First disk eigenfrequency The following table shows the lowest eigenfrequency (Hz) for different sizes of disks      37   Mon Jul 11 15:21:12 2016 Gabriele General Daily Progress One disk installed into the chamber [Alena, Gabriele] We attached one of the silicon lenses to a 1" optical post using some      44   Fri Jul 15 17:56:50 2016 Gabriele General Daily Progress QPD connected to digital system I connected the QPD to the ADC interface with a temporary cable running on the floor. I could get signals. I still have      48   Mon Jul 18 14:29:07 2016 Gabriele General Daily Progress Status of the test setup I checked that the QPD electronics works as expected, and that I can acquire the signals using the ADCs. A new model (x3cr1) is up      49   Mon Jul 18 17:46:04 2016 Gabriele General Daily Progress First look at QPD signals Here's the first spectrum of the QPD X and Y signals, acquired with the digital system. Roughing and turbo pumps are still      53   Tue Jul 19 17:21:48 2016 Gabriele General Daily Progress First modes excited! We can't generate any arbitary signal with the real time model, since awg is not working properly yet. For the moment being      56   Thu Jul 21 12:10:14 2016 Gabriele General Daily Progress Glitch hunting Yesterday I could clearly see the glitches as jumps in the time domain plot of X and Y signals, and trace them to somewhat harder      68   Thu Jul 28 14:01:27 2016 Alena General Daily Progress Clean room Ordered the clean room (hardware+hepa filters) and vacuum gauges      70   Fri Jul 29 14:08:31 2016 Gabriele General Daily Progress Peak tracking code for real time model Summary I wrote a C function to reconstruct the amlplitude and frequency of a line. It can be added as a block into      74   Mon Aug 8 10:42:46 2016 Gabriele General General Dependency of eigenmode frequencies on thickness and diameter I ran a set of COMSOL simulations to determine the dependency of the frequency of each eigenmode on the disk thickness and diameter, within  26x    77   Thu Aug 11 08:45:19 2016 Gabriele General General QPD signals with dielectric filter I installed a dielectric laser line filter (Thorlabs FLH05633-5, center wavelength 633 nm, FWHM 5 nm) in front of the QPD. In this      82   Sat Aug 13 14:05:02 2016 Gabriele General Daily Progress First work on the measurement user interface Today I started programming part of the user interface that will be used to perform the measurements. Not much implemented so      85   Sun Aug 14 18:26:19 2016 Gabriele General General Plans for the automatic mode search Here's how I imagine the mode search to proceed: the user select the list      92   Sat Aug 20 17:01:10 2016 Gabriele General Daily Progress First ring down measurements Everything is working pretty well. This morning the pressure was about 1.2e-6 Torr. I connected the high voltage amplifier and      93   Sat Aug 20 22:18:26 2016 Gabriele General Daily Progress First measured Qs Using the first ring down of the day (GPS 1155754513 + 3600 seconds), I computed the amplitude of each of the modes already identified,  22x    94   Sun Aug 21 08:51:22 2016 Gabriele General Daily Progress New disk installed 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      96   Sun Aug 21 15:36:16 2016 Gabriele General Daily Progress New test 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      97   Sun Aug 21 17:16:03 2016 Gabriele General Daily Progress Ring down measurement with new disk After fixing the setup, the measurement with the new disk looks great. After more than one hour the first two modes are still  22x    98   Sun Aug 21 17:41:34 2016 Gabriele General Daily Progress New test 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      99   Mon Aug 22 08:29:24 2016 Gabriele General Daily Progress New test Restarted roughing and turbo pump at about 8:10am.      100   Mon Aug 22 12:01:52 2016 Gabriele General General Tests of the day Disk excited at 12:01pm. Exited the room at 12:03pm. Opened the chamber at about 2:30pm,      102   Tue Aug 23 08:46:04 2016 Gabriele General Daily Progress Daily tests MO03 - edge polished: Turbo off, QPD centered, before excitation (60 seconds)      103   Tue Aug 23 09:21:25 2016 Gabriele General General Status of Mark Optics disks We initially received 20 disks (75 mm diameter, 1 mm thickness) from Mark Optics. Here's their status as of today      104   Tue Aug 23 09:44:11 2016 Gabriele General General Measurements on MO-02 Two good ring-downs measurements were performed on MO-02. The first one was already reported in a previous elog  7x    106   Sun Sep 11 10:05:33 2016 Gabriele General Daily Progress New substrate in the chamber I installed one of the new substrates (with flats) into the chamber, and started the pumpdown at about 9:45am LT.      107   Mon Sep 12 16:00:06 2016 Gabriele General Daily Progress First fully automated measurements of ring down I finished the first version of the automation software to measure the ring down of the disk modes. I tested it with the new substrate      108   Tue Sep 13 10:33:35 2016 Gabriele General General Disk excited Disk excited with white uniform noise, amplitude 5 V, for some tens of seconds. Excitation off at      109   Wed Sep 14 13:08:05 2016 Gabriele General General Ringdown with roughing pump off At 1:05pm LT I stopped the roughing pump and started a ring-down measurement. Pump restarted at 2:18pm LT.      110   Wed Sep 14 20:17:33 2016 Gabriele General General Band-limited excitation Excitation started at 20:15:30LT, 20 seconds long. The excitation is band-limited (10 Hz) centered around each of the predicted      111   Thu Sep 15 08:13:20 2016 Gabriele General General Pump had no effect on ring down measurements The plot below shows three measurements of the Q of the same disk: during the first two the roughing pump was on, while during      112   Thu Sep 15 08:27:57 2016 Gabriele General General New band-limited excitation Same as in elog #110, but now the amplitude is proportional to frequency squared:      114   Thu Sep 15 15:15:10 2016 Gabriele General General Edge effect on losses I made a COMSOL model that can compute the distribution of elastic energy for each mode, dividing it into:      115   Fri Sep 16 14:06:43 2016 Gabriele General General Pump had no effect on ring down measurements Same plot as below, but this time with estimated 95% confidence intervals for the Q values, as obtained from the fit only.      117   Tue Sep 20 16:12:09 2016 Gabriele General General Pump down As a test, I installed MO1 (the disk with the burn mark, used for the first edge laser polishing test) and started pumping down.      118   Tue Sep 20 16:43:58 2016 Gabriele General General Excitation and ring down The pressure is at abour 3e-6 Torr. I centered the QPD and started an excitation. The HV amplifier manual states that the driver can      119   Wed Sep 21 08:12:13 2016 Gabriele General General Excitation and ring down New excitation (2000V) at about 8:06am. Had to recenter the QPD again after the excitation. Engaged the 500Hz high pass filter      120   Wed Sep 21 14:42:47 2016 Gabriele General General Serialized (etched) disk installed Just for fun, I installed the disk thas has been etched in the center with "1234". I figured out that the ESD PCB was probably      121   Thu Sep 22 09:49:21 2016 Gabriele General General Ring-down of etched disk QPD centerd, quiet data, light off, one minute from PDT: 2016-09-22 09:46:29.393609      128   Tue Sep 27 08:53:46 2016 Gabriele General Vacuum Etched disk installed Installed the etched disk: using manually the centering ring allowed me to get the beam on the QPD. A couple of taps to the      130   Tue Sep 27 15:10:59 2016 Gabriele General Measurements Ring-down of etched disk Quiet (roughing pump off, lights off): 60 seconds from PDT: 2016-09-27 15:05:30.805667 PDT      131   Wed Sep 28 10:26:58 2016 rana General General references on ideal glasses Some easy to read reviews on thin films and ideal glass for people getting started in this Q measuring game.      133   Mon Oct 17 10:50:50 2016 Gabriele General Vacuum No sign of problems in the electrostatic drive I opened the chamber and took the etched disk out. Inspection of the electrostatic drive does not show any sign of burn or damage.      134   Tue Oct 18 16:29:37 2016 Gabriele General Measurements S1600433 S1600433, annealing run 10/10/2016 Installation  Installed in the measurement system, chamber closed pump down started at 4:27pm LT turbo  17x    135   Tue Oct 18 16:52:16 2016 Gabriele General Measurements Sample inspections from annealing run 10/10/2016 LIGO-T1600466 S1600432 shows some residual on face, close to the edge, probably from      136   Wed Oct 19 13:35:23 2016 Gabriele General Measurements S1600438 S1600438, not annealed, as received from Mark Optics Installation Turbo pump switched off at 11:42am (2016-10-19) Turbo      137   Wed Oct 19 16:40:24 2016 sults: General Measurements S1600349 S1600439, not annealed, as received from Mark Optics Installation installed and balanced, pump down started at 4:38pm  10x    138   Wed Oct 19 17:08:47 2016 Gabriele General Measurements S1600433 vs S1600438 S1600433 has been annealed, was contaminated by the iron oxide, and it was cleaned using first contact. No residual      139   Thu Oct 20 11:04:03 2016 Gabriele General Measurements Sample 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  7x    141   Fri Oct 21 13:45:21 2016 Gabriele General Measurements S1600447 Sample S1600447, as received from Mark Optics, second batch Measurements Installed into the chamber, pumping down started at  13x    142   Fri Oct 21 14:03:17 2016 Gabriele General Vacuum Roughing pump moved I moved the roughing pump out of the clean room, adding an extension hose.

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